Apparatus for Developing Photographic Prints

* GB784898 (A)
Description: GB784898 (A) ? 1957-10-16
Apparatus for developing and/or fixing photographic printing material
Description of GB784898 (A)
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BE543185 (A) CH338703 (A) DE1043808 (B) US3000287 (A)
BE543185 (A) CH338703 (A) DE1043808 (B) US3000287 (A) less
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and information originating from other authorities than the EPO; in
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up-to-date or fit for specific purposes.
PATENT SPECIFICATION
4 'l L Date of Applic No 34194155.
Application m( Complete Spec Index at Acceptance: -Class 98 (Z), D 20
G 2.
International Classification: -1 G 03 d.
784 f 898 ation and filing Complete Specification Nov 29, 1955.
ide in Netherlands on Nov 30, 1954.
:ification Published Oct 16, 1957.
COMPLETE SPECIFICATION
Apparatus for Developing and/or Fixing Photographic Printing Material
We, CHEMISCHE FABRIEK L VAN DER GRINTEN N V, a Dutch limited liability
company organized and existing under the laws of the Netherlands,
having a place of business at Venlo, the Netherlands, do hereby
declare the invention, for which we pray that a patent may be granted
to us, and the method by which it is to be performed, to be
particularly described in and by the following statement: -

The invention relates to an apparatus for developing and/or fixing
photographic printing material, particularly diazotype copies, in
which the material is wetted on both sides with a thin layer of
liquid, provided with two rotatable liquid-applying rollers,
contacting each other along generating lines and having surfaces
impervious to liquid, their length being at least 30 times their
diameter and their diameter at least 15 mm Apparatus of this kind is
known.
Generally the wetting of sheet material on one side leads to strong
curling of the material, especially in the production of diazotype
prints by the semi-wet process In this technique therefore
simultaneous wetting of both sides is preferred Thus non-curling, flat
copies are obtained Naturally this is also achieved when
simultaneously developing double-sided copies.
German Utility Model No 1,439,963 describes an apparatus for
developing prints, comprising two applying rollers contacting each
other, as well as means for supplying one of the applying rollers with
the developing liquid and the other with water In this apparatus the
liquid-applying rollers, between which the prints are transuorted, are
mounted in horizontal position one on top of the other Preferably one
of these rollers is covered with soft rubber Apparatus in which one
liquid-applying roller is supported by more than one roller is found
in British Patent Specifications Nos.
656,674, 698,080 and 701,559 Specification
No 656,674 relates to apparatus for developing prints according to the
semi-wet process, in which a liquid-applying roller, which is provided
at its surface with capillary grooves extending transversely to its
axis is supplied lPr with liquid by means of a liquid-transmitting
roller, while the transmitting roller co'-operates with a doctor
device for limiting the quantity 50 of liquid transmitted Apparatus
according to the said specification is especially suited for keeping
the quantity of liquid per surface unit applied to the prints almost
constant in spite of variation of the speed at which the prints 55 are
transported through the apparatus in the said specification an
apparatus (Fig 5) is described for the wetting of prints on both
sides.
In this apparatus two liquid-applying rollers, situated side by side,
co-operate with two 60 liquid-transmitting rollers, while these in
turn co-operate with two doctor rollers According to the said
specification all these rollers may be hard or soft at choice Rubber
is mentioned, as a useful material In British Patent Speci 65
fications Nos 698,080 and 701,559, sinilar apparatus is described to
that in Specification
No 656,674 However, no use is made of liquid-applying rollers the

surfaces of which are provided with grooves extending trans 70 versely
to their axes, but in order to enable the necessary passage of liquid
in the contact zones between the liquid-transmitting rollers and the
liquid-applying rollers the liquid-trans mitting rollers or all the
rollers are provided 75 with annular enlargements at their ends, so,
that the rollers contact one another only at their ends The practice
of photo-printing employs rollers of a diameter which is practically
always more than 15 mm and the length 80 of which is 30 and more times
their diameter.
With such dimensions of the rollers in the usual apparatus the
difficulty is encountered that dry spots may appear on the material
transported between the applying rollers This 85 is attributed to the
fact that the rollers have no uniform mutual contact along their full
length, that is to say that gaps are formed between them, owing to
which the contact of the transported material with, for example, one
90 of the rollers is locally lost, so that locally no liquid is
applied Gaps of a width of an order of magnitude of only 0 1 mm are
sufficient to bring this about.
JA}-dw 784,898 When sheet material is transported between two
liquid-applying rollers between which a gap exists, said material
being narrower than the length of the gap and thinner than its width,
difficulties sometimes arise, such as slipping, especially when, as is
usually the case, the apparatus is not provided with special transport
means.
Naturally the phenomena in question are less troublesome if the
rollers have a soft covering of sufficient thickness, but such soft
coverings have other drawbacks Such rollers run heavily and thin
sheets of relatively large dimensions tend to crease while running
through the apparatus In fact, in consequence of the unequal local
contact-pressure between the rollers, the pressure between the rollers
and the material transported between hem is locally different
Moreover, owing to the varying degrees of compression of the sott
cover, differences arise in the active radius of the roller, which
lead to differences in tangential speed.
The present invention overcomes these dilfficulties.
According to the invention at least one of the rollers is at least
partially supported by the other roller and is lengthwise so flexible
that, if lying in a horizontal position and supported at the ends
only, it sags by its own weight substantially along a continuous or
broken curve, the sag ot its lowest generating line being at least t
i' o, of the lengmth of the roller.
Thus, for example, a roller O 80 cm long may have a minimum degree of
sagging of G 6 mm.
and it is to be rated that this as a nigh value in relation to the

average paper tiickness, which amounts to approximately 0 1 mnn.
In the apparatus according to the invention one of the liquid-applying
rollers thus has a flexibility which permits this roller to adapt
itself completely or at least considerably to tue other roller or
rollers with which it co-operates.
Owing to this the appearance of dry spots during the wetting of sheet
material on both sides is avoided Gaps become smaller or are fully
eliminated so that the transport of sheet material, especially narrow,
thin sheet material, is considerably improved The contactpressure
between the liquid-applying rollers becomes more uniform, so that even
when the flexible roller is made of soft material, the contact between
the rollers and the material transported between them is practically
the same in the circumferential direction along the full length of the
liquid-applying zone, and no differences in tangential speed occur.
The invention will be more fully described with reference to the
drawings.
Figs 1-3 are diagrammatic cross-sections, perpendicularly to the axes
of the cooperating applying rollers of apparatus according to the
invention in different embodiments.
Fig 4 illustrates diagrammatically the distribution of forces in
apparatus according to Fig 2.
Figs 5-10 show various embodiments of flexible liquid-applying rollers
for apparatus according to the invention, in diagrammatic
cross-sections.
In the Figures 1, 2, and 3, 1 and 2 are the 70 liquid-applying rollers
which deliver in the applying zone 27 a thin layer of liquid 35, e g.
a diazotype developer, on to both sides of the material to be wetted
40, e g diazotype paper of weight 80 g/m 2 The rollers in the appara
75 tus according to the Figures 1, 2, and 3 rotate in the directions
indicated by arrows.
In Fig 1, liquid-applying roller 1 is rotatably mounted in trough 33,
which is partly filled with liquid 35 The trunnions of roller 80 1 are
supported in bearings forming part of the frame 30 Liquid-appiymng
roller 2 is a flexible tube filled with liquic, e g a rubber hose,
provided at its ends with trunnions 7 It rests on roller 1 and is held
in position by 85 trunnions 7 located in slots 32 in the frame Both
rollers have a length of 120 cm.
Roller 1 has a diameter of 30 mm, roller 2 of 27 mm Roller 1 is an
"ordinary" roller, e g.
a solid, metal roller, which, in spite of its rigi 90 dity but in
consequence of its own weight and the weight of roller 2, sags
somewhat for example, Dy about O 2 mm in the middle.
Because the tubular roller 2 can sag at least 0.1 per cent of its
length, this roller can 95 wholly follow the sagging of roller 1 The

surface of roller 1 may be smooth or profiled.
Roller 2 has a surface provided with capillaries, which receive a
quantity of liquid from trough 33 via roller 1 when the apparatus is
100 in operation without any materials being transported between the
two rollers This quantity of liquid is delivered during the transport
of sheet material Apparatus according to Fig 1 is suitable for the
wetting of sheets on both 105 sides, the top roller being permitted to
fill its capillaries at intervals between the wetting of the sheets.
In the apparatus according to Fig 2 two troughs 33 and 34 are located
at a short dis 110 tance from each other Both are partly filled with
liquid 35 Liquid-applying roller 1 is rotatably mounted in trough 33
and liquidtransmitting roller 3 is rotatably mounted in trough 34 Both
rollers are provided with 115 trunnions, 6 and 8 respectively, which
are supported in stationary bearings Liquidapplying roller 2, which is
a flexible roller according to the invention, rests on the rollers 1
and 3 It may be supported by means 120 of trunnions, or may be freely
supported The sheet material 40 is transported between the troughs 33
and 34 and the rollers 1 and 2.
A thin layer of liquid is applied on both sides in zone 27 In this
apparatus the rollers 1 and 125 2 are continuously supplied with
liquid, so that the sheet material 40 may be a long web.
In the apparatus according to Fig 3 the troughs 33 and 34 are situated
at a greater distance from each other than in the apparatus 130
784,898 according to Fig 2 In both troughs liquidtransmitting rollers,
4 and 3 respectively, are rotatably mounted They are provided with
trunnions, 9 and 8 respectively, which are supported in stationary
bearings The liquidapplying rollers 1 and 2 rest on the
liquidtransmitting rollers 3 and 4, and at the same time rest against
each other One of the liquidapplying rollers must be flexible but the
other may be an " ordinary " rigid roller Alternatively both rollers 1
and 2 may be flexible rollers, but in that case at least one of them
must be supported in bearings at its ends and must be rigid enough to
hold itself and at the same time the other liquid-applying roller in
their position of co-operation with the liquidtransmitting rollers 3
and 4 Thus e g the trunnions 6 of roller 1 may be supported in
stationary bearings Roller 2 may be freely supported; it may, however,
also be provided with trunnions 7 which are supported in bearings
Liquid-applying rollers 1 and 2 are continuously supplied with liquid
by liquid-transmitting rollers 4 and 3 The surfaces of the
liquid-applying rollers 1 and 2 of apparatus according to Figs 2 and 3
may be smooth or profiled (e g grooved) Also the surfaces of the
liquid-transmitting rollers 3 and 4 may be smooth or profiled For
satisfactory functioning of the apparatus it is, however, necessary
that a sufficient quantity of liquid is let through in the contact

zones between liquid-transmitting and liquid-applying rollers.
It is desirable to provide ample opportunity for passage of the liquid
in the contact zones between liquid-transmitting rollers
and'liquidapplying rollers, but to limit the quantity of liquid let
through This may be done by means of a doctor device for doctoring off
the excess of liquid from the surface of the transmitting rollers Such
a doctor device is, for example, the doctor roller 5 indicated in
dotted lines in Fig 3 By means of such doctor devices an almost
unvarying liquid application may be obtained at varying transport
velocities of the sheet material.
Fig 4 diagrammatically illustrates how, in an apparatus according to
Fig 2, roller 2 exerts pressure on both the lower rollers 1 and 3.
The vectors 22, 23, and 24 illustrate respectively what forces act on
the rollers 2, 1, and 3 owing to their own weights The weight of
roller 2 may be resolved into the vectors 22 a and 22 b, which
represent the forces with which the lower rollers are loaded by the
weight of roller 2 The total forces acting on the rollers 1 and 3 are
ultimately determined in magnitude and direction by the vectors 25 and
26 Under the influence of these forces the lower rollers will sag
somewhat in the direction of the vector 25 and 26 As the rollers 1 and
3 are supported at their ends, the sagging will be greatest in the
middle of the rollers and will decrease towards the ends Generally
this sagging will be different for the various rollers, but at least
different for the rollers 1 and 3 on the one hand and the roller 2 on
the other hand Thus, gaps appear in the liquidapplying zone 27 and in
the contact zone 28.
In an apparatus according, to Fig 2, liquid 70 applying roller 2 may
be so compressible that its roller profile is not perfectly circular
when it rests on the rollers 1 and 3 Preferably, however, the flexible
roller in the apparatus according to the invention is elastically
deformable, 75 though with sufficient rigidity substantially to
preserve its circular section.
Fig 5 is an illustration of a longitudinal section of a roller
consisting of a tube 11 with circular section The tube may be made,
for 80 example, of relatively soft rubber (e g 50-70 Shore) and may
have a wall thickness of a few millimetres Such a tube is very
flexible lengthwise, whereas its cross-section is rather rigid.
In an apparatus according to Fig 2 roller 2 85 works very well when it
is made according to Fig 5 Alternatively tubes made of softer
materials or rubber tubes with a very thin wall may be used Thus, for
example, it is possible to construct flexible, elastically deformable
96 tubular rollers, with sufficient rigidity substantially to preserve
the circular roller profile, by means of a cover of flexible material,
e g.

waterproof tissue with an inner coating of a continuous row of rings,
the outer diameter of 95 which is equal to the inner diameter of the
cover When using a rubber tube with a wall thickness of 1 mm or less
it is possible to obtain sufficient rigidity to preserve the circular
roller profile by closing the tube at its 10 '0 ends and charging it
with air under pressure.
Fig 6 illustrates a diagrammatical longitudinal section of a tubular
roller the elastically deformable tube wall of which consists of a
cover 11 and a spiral spring 12 Small plates 105 13 close the tube at
the ends Instead of spiral spring 12, separate rings may also be used
for internally supporting the cover 11.
In apparatus for wetting sheet material on both sides the
liquid-applying rollers also often 110 have to provide for the
transport of the material against a certain resistance Often broad and
long sheet-shaped material has to be transported through the
apparatus, for example, as a somewhat tensioned web In 115 order to
obtain a sufficient pull for this, the liquid-applying rollers either
have to be pressed against each other with the necessary force, or
have to be heavy enough when they rest on or against each other by
their own weight 120 In the apparatus according to the invention a
sufficient pull between the liquid-applying rollers may easily be
obtained by providing a tubular flexible liquid-applying roller with a
filling of a fluid substance or of solid bodies 125 of substantially
length and arranged axially adjacent each other and which are movable
in relation to one another, at least in a direction transverse to the
tube The fluid substance may be a liquid, e g water, aqueous solutions
13 Q or mercury or a powder or granular material, such as sand or
gunshot.
Fig 7 illustrates in diagrammatic longitudinal section a tubular
roller with elastically deformable cover 11, which is filled with
pieces of solid material 15 a and 15 b which are movable in relation
to each other The material is, for example, iron Instead of using
fairly large pieces of such material, such as 15 a and 15 b, the tube
may be filled with smaller pieces such as the discs 16.
The pieces 15 a and 15 b are ball-and-socket jointed so that they can
hinge in relation to each other, but cannot relatively move in a
direction transverse to the axis of the tube.
The rollers according to Figs 5, 6, and 7 not being provided with
trunnions, they are only suited for use in apparatus in which they are
supported by at least two other rollers, such as the apparatus
according to Figs 2 or 3 In apparatus according to Fig 1 it is
necessary to give the flexible roller some bearing, in order to
prevent its rolling off the lower liquidapplying roller The
flexibility of the roller in this apparatus must however be limited In

the apparatus according to Figs 2 and 3, it is also desirable to give
the flexible rollers some bearing, in order to prevent their being
displaced, e g owing to impact Flexible rollers suited for being
supported in bearings consist of a tube provided with a continuous
rigid core, with sufficient freedom of transverse movement in relation
to the tube wall and the tube filling respectively for preserving the
desired degree of deformability of the tube wall These flexible
rollers are easier to handle than those without a core They can easily
be taken out of the apparatus and stored with the ends of the core
resting on supports.
In the flexible roller according to Fig 8 the elastically deformable
tube 11 is closed at its ends by plates 14 Core 10 with trunnions 7
has been passed through these plates and is fastened to them The space
between core 10 and the inner wall of tube 11 is partly filled with
rings 17 These rings are provided with holes of a greater diameter
than that of core The outer diameter of the rings is smaller than the
inner diameter of the tube 11 Thus the roller according to Fig 8 has
good transverse deformability along its full length.
It has been proposed, for the improvement of the paper transport
through apparatus for single-sided development of photographic papers,
to place on top of the liquid-applying roller, rotating in a liquid
trough, a roller consisting of a rigid shaft over which is slipped a
continuous row of discs which are covered with rubber on their
circumference, the holes in the discs having a greater diameter than
the shaft The discs press the paper uniformly against the
liquid-applying roller The apparatus is not suited for simultaneously
wetting sheet material on both sides Such a discroller would involve
serious drawbacks when used as a liquid-applying roller On the seams
betwen the discs more or less liquid would be applied on to the paper
than on the running surfaces of the discs The liquid would penetrate
between the discs, and between them and 70 the shaft, and cause
fouling and corrosion of the roller.
Fig 9 illustrates a roller of a similar construction to that according
to Fig 8 The filling consists of granular bodies 18 and 19 75 Granules
18 have a smaller size than granules 19 with equal specific gravity,
or have higher specific gravity with equal size This flexible roller
will thus apply a higher pressure against the other roller or rollers
in the middle than 80 at its ends.
In the flexible roller according to Fig 10 the space between core 10
and the inner wall of tube 11 is partly filled with liquid 20 When
tube 11 is very flexible, its circular roller pro 85 file may be
preserved by means of small discs 21, which are secured to core 10 at
regular intervals These small discs may be provided with holes so that
the compartments into which they divide the tube are interconnected 90

In the flexible rollers according to the Figs.
9 and 10 the spaces between core 10 and the inner wall of tube 11 may
be completely filled with the fluid substances 18, 19, and 20
respectively 95 In order to obtain an even distribution of a thin
layer of liquid on both sides of the sheet material, the surfaces of
the liquid-applying rollers preferably are provided with capillary
recesses Suitable recesses are, for example, 100 pits, while grooves
extending transversely to the axes of the rollers along their
circumference are also very suitable Grooves of a depth of, for
example, 1 mm and a width of 0 15 mm at distances of 0 45 mm are very
suitable 105 When in the apparatus according to the invention the
flexibility of the flexible rollers, and accordingly the uniformity of
the applying pressure in the liquid-applying zone between the
liquid-applying rollers is increased, it is 110 possible to decrease
the applying pressure per unit at length of the rollers and yet retain
sufficient pull for the transport of broad and long sheet material as
well as sufficient uniformity of liquid-application Low applying 115
pressure is advantageous when working with vulnerable materials e g
materials the surface of which is coated with a soft film layer.
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* GB784899 (A)
Description: GB784899 (A) ? 1957-10-16
Improvements in pectifier cell mountings
BE543951 (A) CH347900 (A) DE1010186 (B) FR1143327 (A)

NL100659 (C) US2756374 (A)
BE543951 (A) CH347900 (A) DE1010186 (B) FR1143327 (A)
NL100659 (C) US2756374 (A) less
PATENT SPE Ci Fi CATION
784,899 Date of Application and filing Complete Specification Dec 22,
1955.
& 1 I No36801/55.
Application made in United States of America on Dec 27, 1954.
Complete Specification Published Oct 16, 1957.
Index at Acceptance:f-Casses 37, EC( 1 AA: 2 A 2: 2: 5: 6 D); 82 ( 1),
Ag(E: F: J: M: R: V), A( 15 B:
X); and 33 ( 4), 54.
International Classification: l C 22 o T-101 o COMPLETE SPECIFICATION
l.>r 6 Dnrer- et En ectrie Rf lell 2 ea-Mnueamgs We, GENERAL ELECTRIC
COMPANY, a Corporation of the State of New York, United States of
America, having its office at Schenectady, 5, State of New York,
United States of America, do hereby declare the invention, for which
we pray that a patent may be granted to us, and the method by which it
is to be performed, to be particularly described in and by the
following statement:-
This invention relates to mountings for metallic rectifier cells and
particularly to that type of mounting in which the rectifier cell is
enclosed in order to protect it from deleterious agents found in the
atmosphere or in surrounding media.
Metallic rectifiers having thin barrier layers and operating at
relatively high voltage are adversely affected by the presence of
moisture and certain other materials to which they may be subjected in
storage or in use The ever present moisture in the atmosphere is a
controlling factor although the presence of other surrounding media
such as dust, corrosive fumes, fungus, and organic materials such as
may be used as cooling fluids or solvents for potting compounds for
the cell may assume equal importance in their effect on the cell.
When rectifier cells are used or stored in the presence of high
humidities, they may be protected by certain moisture resisting paints

and varnishes which are satisfactory for certain applications For
other applications the cells must be protected by immersing them in a
suitable liquid, by encapsulating or enclosing them in a suitable
compound, or by providing them with hermetically sealed enclosures.
The cell mounting should also provide for the dissipation of the heat
losses in the cell A cell having a high current capadity for its
physical size will have such a small thermal mass that its heat loss
must be dissipated as fast as it is generated or the cell will
overheat and be destroyed Consequently the cell mounting must have a
suitable structure for conducting this heat loss to suitable storage
or dissipating mnembers associated with the lPrice 3 j, Lol cell
Furthermore the cell mounting must have a structure which will permit
fabrication thereof without applying destructive temperatures to the
cell.
The problems above considered are especially acute in monocrystal
semiconductors of the P-N junction type as exemplified by germanium
and silicon cells Thus a germanium cell about '/1, inch in diameter
and about 20 mils thick will provide half wave rectification at 65
volts and 75 amperes with a heat loss of about 60 watts This heat loss
must be dissipated as fast as it is generated or the cell will
overheat and be destroyed The cell may also be destroyed if heated
above a critical temperature during the fabrication of its mounting
Furthermore the very thin barrier layer in such a cell operating at
high voltage is adversely affected by high humidities and by the
presence of other deleterious agents to which it may be subjected
Unless surface contamination of the cell at the P-N junction barrier
region is prevented, the cell may fail electrically and be destroyed.
The present invention provides a cell mounting which completely
encloses the cell, may be hermetically sealed, and has a physical
structure which may be separately fabricated to accommodate terminal
connections which serve as current conductors while dissipating the
heat generated in the cell by current flow therethrough.
A mounting for a unilaterally conductive cell having oppositely
disposed contact surfaces, according to the invention comprises a
metallic plate having an area in electrically conductive engagement
with one contact surface of the cell to extend laterally thereof, a
metallic cup having a closed end in electrically conductive engagement
with the other contact surface of the cell and a radially enlarged
open end portion, an apertured cell-enclosing body of electrically
insulating material provided with spaced flanges, one of which extends
radially inwardly of the body to define a socket for disposition of
the radially-enlarged cup portion in bonded engagement therein, the
other flange 784,899 extending radially outwardly in bonded engagement
with the metallic plate Preferably, the cell-enclosing body is of

impervious ceramic material having metallized end surfaces and the
spaced flanges comprise a metallic rim plate and a metallic closure
plate respectively bonded and sealed to the metallized end surfaces,
the rim plate extending radially inwardly to define a cylinder for
complemental reception of the radially-enlarged cup portion.
The rectifier cell mounting thus conveniently comprises a rectifier
cell sandwiched between a metallic plate and the closed end of a
metallic cup One contact surface of the cell is in conductive
engagement with a central area of the metallic plate which is large
enough to provide a border area surrounding this central area and
extending laterally of the cell.
The closed end area of the metallic cup has a surface area which is
the same or smaller than the other contact surface of the cell so that
the edge area of the cell is ex posed This assembly is enclosed by a
hollow body of electrically insulating material having at one end
thereof an outwardly extending rim portion joined to the border area
of the metallic plate engaging one contact surface of the cell and has
at its other end an inwardly extending portion with a central opening
therein formed by an axial outwardly extending flange of the same
predetermined configuration as the open end side wall structure of the
cup with which it makes an overlapping telescopic engagement and to
which it is joined This enclosure may be formed of a hollow impervious
ceramic cylinder the opposite ends of which have been metallized and
bonded to metallic rings respectively extending inwardly and outwardly
from the walls of the cylinder to provide the rim portion and the
inwardly extending portion of the hollow body above referred to.
When the metallic plate and metallic cup referred to above are of
circular contour the plate becomes a disc and the open end of the cup
becomes a cylinder each having outer edges which respectively match
and are coextensive with the outer and inner edges of the rings
attached to opposite ends of the ceramic cylinder These edges may be
joined by a fusion welding operation which can be made without
damaging the cell due to heat flow through the parts to the cell The
resulting structure provides a hermetically sealed enclosure for the
cell as well as terminal connections through the disc and closed end
of the cup for conductors having terminals of a cross sectional area
respectively substantially equal to and greater than the areas of the
contact surfaces of the cell sandwiched therebetween.
The construction and advantages of the enclosed mounting for a
rectifier cell will become apparent from the following detailed
description of the embodiment shown in the accompanying drawing, in
which Fig 1 is a sectional view of a rectifier cell mounting embodying
the invention and Figs 2 and 3 are respectively a sectional view of
the rectifier cell subassembly and a sectional view of the cell

enclosure subassembly which are joined to one another to form the cell
mounting.
The rectifier cell subassembly comprises a unilaterally conductive
cell 1 having planiform contact surfaces which is sandwiched between a
metallic disc 2 and a metallic cup 3 having cylindrical side walls One
contact surface of the cell is in electrically conductive engagement
with a central area of disc 2 which consequently has a border area
surrounding this central area and extending laterally of the cell The
outer closed end of cup 3 is in electrically conductive engagement
with the other contact surface of the cell The side wall structure of
the cup has been stepped so that its outer end may be of a
predetermined standard size while its inner end is of a size which
will leave the edge of cell 1 exposed.
The disc and cup constitute electrodes for cell 1 and may be attached
thereto in any suitable manner depending on the nature of the cell.
The cell may be formed of a wafer of germanium about 9/,, inch in
diameter and about mils in thickness The closed end of the cup has
been attached to one contact surface thereof by an indium solder and
its other contact surface has been joined to the central area of disc
2 by means of an arsenic-tin solder.
Any suitable metal may be used for the disc and cup shaped electrodes
but in the embodiment under consideration these have been made of an
alloy of 58 ' iron and 42 nickel and have a thickness of about 12 mils
The alloying operation is performed in a furnace in the presence of a
hydrogen atmosphere at a temperature of the order of 4500 to 6500 C.
Preferably a germanium cell wafer having N characteristics is employed
During the alloying operation the indium dissolves some of the
germanium and upon cooling a "-M junction is formed in the wafer
adjacent the surface layer of indium which acts as a solder to bond
the closed end of Cu D 3 to one -ontact surface of the germanium wafer
The side wall of cue 3 is stepped so that the a-es of its closed end
is less than that of the contact surface of the cell which it engages
This leaves the edges of the cell exposed and makes it possible to
clean the edges of the cell after soldering to eliminate surface
contamination and short circuiting of the P-N junction barrier region
of the cell A chemical or electro chemical etch may be employed for
this operation For example electrolytic etching in a sodium or
potassium hydroxide solution or an immersion in concentrated nitric
acid may be used Disc 2 is soldered to the germanium wafer by an
arsenic-tin solder which has been selected so as not to impart P
characteristics to this contact surface of the germanium wafer.
The cell enclosure subassembly shown in Fig 3 comprises a hollow
cylinder of ceramic 784,899 material 4 having opposite ends thereof
metallized with silver and bonded to metallic rings and 6 respectively

extending outwardly and inwardly from the walls of the cylinder The
outwardly extending ring 5 has an outer diameter equal to the diameter
of disc 2 of the cell subassembly so that when these two subassemblies
are placed together these outer edges will be co-extensive with one
another.
The inwardly extending ring 6 has about the opening therein an axially
extending cylindrical flange 7 having an inside diameter equal to the
outside diameter of the side wall of cup 3 at its open end The
thickness of the ceramic member 4 and of the ring 5 and 6 together
with the extension of rim 7 of ring 6 is such that when ring 5 is
placed on disc 2 the outer edge of rim 7 and the outer edge of the
wall structure of cup 3 are coextensive with one another.
The hollow ceramic cylinder 4 may be formed of fused alumina which is
impervious to gases and liquids and the rings 5 and 6 may have a
thickness of about 15 mils and be formed of an alloy containing 54 %
iron, 29 % nickel and 17 % cobalt The assembly of these parts into an
integral unit is obtained by brazing in an oven at about 9000 C using
silver as the bonding metal between rings 5 and 6 and the silver
coated end surfaces of cylinder 4.
The sub-assemblies shown in Figs 2 and 3 are assembled as shown in Fig
1 and the coextensive outer edges of ring 5 and flange 7 of the
sub-assembly of Fig 3 are joined to the outer edges of disc 2 and cup
3 of the subassembly of Fig 2 The joints between these edges may be
made in ally suitable manner but it is preferred to secure a sealed
union at these joints by means of fusion welds 8 and 9.
These welds are preferably made by the socalled inert arc welding
process in which an arc is established between the seam parts and a
tungsten electrode while shielding the arc and molten portions of the
weld metal with an inert atmosphere such as argon, helium, or a
mixture of these gases It is preferred to use argon as a shielding gas
in order to obtain a low current arc the energy of which is sufficient
to produce by localised heating the beads of weld metal 8 and 9
without having a heat carry over through the parts to cell 1 which is
sufficient to destroy it Once a germanium cell has been formed as
above described, it cannot be heated to or above 1560 C without risk
of destroying the cell by reason of melting the indium solder used
therein.
By using the inert arc welding process it is not necessary to use a
flux at the joint being welded and consequently there is no
possibility of contaminating the interior of the cell mounting as
might result if a flux were used.
Furthermore some of the inert argon gas is introduced into the
enclosed interior of the cell mounting and consequently reduces the
oxygen content of the gas mixture in contact with the cell Furthermore

during inert arc welding there is no formation of water vapour and any
small amount of water vapour in the air mixture sealed within the cell
mounting 70 is insufficient to cause any damage to the cell.
The completed cell mounting 10 shown in Fig 1 may be used in various
ways one of which has been illustrated in Fig 4 As there shown, disc 2
thereof is soldered to the body 75 portion 11 of a terminal lug 12 and
the inner surface of the closed end of cup 3 is soldered to the end of
a cylindrical terminal 13 formed at one end of a flexible braided
conductor 14 having at its other end a terminal 15 which is 80
soldered to a terminal lug 16 These terminal lugs 12 and 16 are part
of a terminal block formed by mounting the flanged edge of terminal
lug 16 on the body portion 11 of terminal lug 12 by means of
insulating bolts 17 85 Strips of insulating material 18 are interposed
between the overlapping portions of the terminal lugs which are held
in parallel spaced relationship with one another to form a mechanical
shield for the rectifier cell mounting 10 90 The body portion 11 of
terminal lug 12 is provided, on its side opposite from the side on
which cell 10 is mounted, with a plurality of heat radiating fins 19
which are held in place relative to one another and the body portion
95 of terminal lug 12 by means of screws 20 The body portion 11 of
terminal lug 12 on the side opposite from this lug is provided with a
stiff portion 21 which extends in the same direction as the fins 19
and serves as a guard and 100 buffer for these fins which may be made
of relatively thin sheet metal It will be noted that terminal lug 16
is offset from extension 21 of base 11 of terminal lug 12 Consequently
lug 12 of another terminal block may be bolted 105 to lug 16 without
short circuiting the lugs of any one block.
The attachment of the cup and disc of the cell mounting to the body
portion 11 of terminal lug 12 and to the end portion of ter 110 minal
13 may be made by solder having a melting point of about 1030 C formed
of 53 9 % bismuth, 29 6 % tin and 24 5 % cadmium The surfaces to be
joined are pretinned with this solder and joined in an oven at about
130 C 115 using an acid flux to facilitate joinder of the parts by
reason of the solder on the parts flowing together.
The component parts may thus be separately fabricated at temperatures
which would be 120 destructive to the rectifier cell and thereafter
assembled under conditions which, by reason of the structure of these
parts, may be joined by welding without transmitting sufficient heat
to the cell to cause its destruction Further 125 more the arrangement
provides for hermetically sealing the cell and thus excluding
therefrom all deleterious agents in the atmosphere or in any media to
which it may be exposed.
The invention is not limited to mounting 130 784,899 mcnocrystal
semiconductor cells as above described but may be used for mounting

other types of rectifier cells such as copper oxide or selenium cells
Furthermore for certain application the assembly of parts need not be
secured in fhe specific manner above disclosed.
Thus instead of making the closure joints by arc welding, other fusion
welding methods may be used provided the heating is so localized as
not to damage the cell Furthermore resistance welding procedures may
be used; projection welding being used to attach disc 2 to ring 5 and
a suitable line welding procedure being used to join the open end of
cup 3 to flange 7 of ring 6 To facilitate this latter operation the
overlap of members 3 and 6 may be made greater than that shown in the
drawing Also instead of welding the subassemblies to one another, the
union of these parts may be secured in other ways as by using solders
or plastic cements Furthermore the material from which the parts of
the subassembly are made need not be the specific alloys above
described Under certain circumstances the metallic parts of the cell
mounting may be formed of any suitable metal or alloy, copper and its
alloys being particularly useful in this respect by reason of their
electrical and heat conducting characteristics The outwardly and
inwardly extending portions described above as being formed of metal
and bonded to the ends of the hollow cylindrical insulating member may
alternately be made integral with this hollow insulating member and of
the same material of which it is formed.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB784900 (A)
Description: GB784900 (A) ? 1957-10-16
Improvements in or relating to methods of and apparatus for entraining
granular or powdery material in an upwardly flowing gas stream

COMPLETE SPBCIFI CATION
Improvements in or relating to methods of and Apparatus for
Entraining Granular or Powdery Material in an Upwardly
Flowing Gas' Stream
We, N. V. DE ATAAFSCHE PETROLEUM MAATscHAPPIJ, a company organised
under the laws of The Netherlands, of 30 Carel van
Bylandtlaan, The Hague The Netherlands, do hereby declare the
invention, for which we pray that a patent may be granted to us, and
the method by which it is to be performed, to be particularly
described in and by the following statement:
The invention relates to methods of and apparatus for entraining
granular or powdery material in an upwardly flowing gas stream.
The need to entrain such material in an upwardly flowing gas stream
frequently arises for example in chemical plant and allied 1equipment
in which it is required to transport the material from one part of
the plant or equipment to another. The material may for example be
catalytic material for a reaction which is carried out in the presence
of a fluidised catalyst bed, or granular material which is circulated
in the fluidized state and acts as a heat transmission medium. In the
,latter case 'the granular material is, for example thirst heated in a
hot gas stream, and afterwards gives off heat to nests of tubes over
which it floves in a fluidized state and through which a medium to be
heated circulatex
It is an object of the invention to provide apparatus for entraining
granular or powdery material in an upwardly Bowing gas stream such
that the material is uniformly mixed with the gas stream, as a result
tof wich erosion is avoided as much as possible in the riser into
which the gas/material stream flows.
Apparatus according to the present invention for entraining powdery or
granular material in an upwardly flowing gas stream comprises an
upwardly directed supply line for
the gas stream leading to an upwardly directed riser one or more slots
being formed between
the ends of rhe supply line and the riser providing one or more
annular passages directed in the direction of gas flow in operation,
or at a small angle to it, for the passage of the material into the
riser from a feed' chamber which surrounds the slot or slots. and is
provided with means for use in maintaining any granular or powdery
material within it in a fluidised state, said means including gas
supply nozzles, located both above and below the slot or slots.
The upper end of the supply line may pro ject into the lower end of
the riser, a slol being formed by the space between the supply line
and the riser. In another case, the upper end of the supply line and

the lower end of the riser are spaced apart, one or more rings being
mounted between them, and the slots being formed between the ends of
the ring ol rings and the upper end,' of the supply line and the lower
end of the riser. The lower end of the riser may be wider than the
upper end d the supply line, a plurality of rings being provided which
are of gradually increasing width forming a gradually widening passage
joining the ends of the supply line and the riser.
A number of embodiments of apparatus according to the invention and
their method ,of operation will now be described with reference to the
accompanying drawing, in which:
Figures' 1, 2, 4 and 7 are diagrams showing longitudinal sections of
various embodiments of apparatus according to the invention.,
Figures 3 and 5 show details of the Figures 2 and 4 respectively, and
Figure j6 is a cross section of Figure 5.
In the apparatus shown in Figure 1, the inlet of a riser 1 up which it
is required to transport a supply of granular or powdered (referenoe
will be henceforward only to granular material) material is positioned
around the end lof: a supply line 2 for the transport gas which flows
in the direction of the arrow 3,,
The riser 1 is wider than the line 2 and overlaps it by a short
distance so that an annular slot 4 is formed providing communication
between the interior of the riser 1 and the feed chamber 5 from which
the granular material is drawn, the lower end of the riser 1 being
secured to the wails of the chamber 5 by supports 1-6 The chamber 5 is
provided with a gas distributing means 6 to which an auxiliary gas is
supplied through the line 7 in order to keep the granular material 8
present in the chamber 5 in a fluidised state. An additional gas
supply line 17 is provided also for supplying gas to an additional gas
distributing means 18. This serves to maintain the granular material
above the slot 4 in a fluidised state and is required as the greater
part of the gas supplied through the distributing means 6 escapes
through the slot 4. Without the additional distributing means 18 to
maintain the granular material fluidized above the slot 4, operation
tends to become irregular. The amount of granular material 8 present
in the feed chamber 5 is regulated in operation in such a way that the
static pressure set up at the slot 4 is greater than the pressure of
the transport gas at the outlet of the line 2. As a result the
material 8 flows through the annular slot 4 to the interior of the
riser 1 forming initially a thin screen 9 surrounding the stream of
transport gas. An intense mixing of the granular material with the
transport gas then occurs, with the result that the material is
entrained in rhe gas stream and transported up the riser 1 to a higher
level.
The shape and position of the slot 4 of the apparatus shown in Fig. 1

are such that the screen 9 first extends along the inner wail of the
riser 1.. In the apparatus shown in Fig.
2, on the other hand, the ends of the riser 1 and the line 2 are
shaped and arranged so ,that there is a constriction at the slot 14
which results in the material being sprayed into the riser 1 along the
surface of a cone having an acute apex angle. A detail showing the
slot 10 is given in Fig. 3. The operation of the apparatus shown in
Figs. 2 and 3 is much the same as that of the apparatus shown in Fig.
1.
The apparatus shown in Fig. 4 has a number of slots 11 situated one
above the other, a series of overlapping rings 12 being arranged in
between the end of the supply line 2 for the transport gas and the
inlet and of the riser 1..
The rings 12 which increase in diameter in an upward direction, rest
on each other and are centred "with respect to each other by three
supports 13 attached to each Fig. 5 shows the slots 11 on an enlarged
scale.
Good results are also obtained if the slots 11 are interrupted at
reguIar intervals by prosections 14 formed on the rings 12 as shown in
Fig. 16 which shows a section at the line VI VI in Fig. 5 in a case
where such dams are provided. In this embodiment, the separate
supports 13 may be dispensed with. In yet another embodiment shown in
Fig. 7, strips 15, bent round to form frusto-conical rings are
provided between the ends of the riser 1 and the supply line 2 and are
positioned in a suitable manner at the given distance with respect to
each other. As it is desirable not to iload either the rings 12 '(Fig.
4) or the rings 15, (Fig.. 7) the riser 1 does not rest on them but is
secured, for example by the supports 16, to the feed chamber 5 as
shown in Figure 1, 2, 4 and 7.
As shown in Fig. 4, the bottom 19 of the feed chamber 5 is detachable.
The rings 12 can then be removed through the opening formed by
removing the bottom 17 of the feed chamber 5.
In order to minimize the erosion in the riser 1, the velocity of the
gas/granular material mixture in it should be as low as possible.
This, however, increases the chance of granular material falling back
and such material as does fall back may cause clogging of the supply
line 2 for the transport gas. This can be prevented by designing the
outlet of the supply line 2 so that it is smaller than the inlet of
the riser. It is true that the higher gas velocity occurring in the
extremity of the supply line does not prevent the granular material
from falling back into the riser, but prevents this material from
penetrating into the supply line for the transport gas.
As already observed', the granular material should be supplied in a
mainly axial direction to -the outermost zone of the stream of

transport gas as in this zone the velocity of the gas is lowest, with
the result that the loss of impact energy between the material
supplied and the gas stream will be as small as possible.
If it is required to transport relatively large quantities of granular
material, it will be advantageous for the same reason to supply this
material through more than one slot to the outermost zone of the
stream of transport gas.
What we claim is: -
1. 'Apparatus for entraining granular or powdery material in an
upwardly flowing gas stream, comprising an upwardly directed supply
line for the gas stream leading to an upwardly directed riser, one or
more slots being formed, between the ends of the supply line and the
riser providing one or more annular passages directed in the direction
of gas flow in operation, or at a small angle to it, for the passage
of the material into the riser from a feed chamber which surrounds the
slot or slots and is provided with means for use in maintaining any
granular or powdery material wi-thin it in a fluidised state, said
means including gas supply nozzles located both above and below ,the
slot or slots.
2. Apparatus according to claim 1 in which the upper end of the supply
line projects into the lower end of the riser a slot being formed by
the space between the sllnnlV line and the riser.
* GB784901 (A)
Description: GB784901 (A) ? 1957-10-16
Improvements in or relating to electrical selecting systems
BE546114 (A) DE947893 (C) FR1096738 (A) US2931013 (A)
BE546114 (A) DE947893 (C) FR1096738 (A) US2931013 (A) less

Inventor: LIONEL ROY FRANK HARRIS 784,901 Date of filing Complete
Specification (under Section 3 ( 3) of the Patents
Act, 1949) Jan 18, 1954.
Application Date Jan20, 1953 No 1684/53.
Application Date April 14, 1953 No 10220/53.
Index at acceptance: -Class 40 ( 4), K 1 U 3.
International Classification: -H 04 m.
COMPLETE SPECIFICATION
Improvements in or relatirng to Electrical Selecting Systems I, HER
MAJESTY'S POSTMASTER GENERAL, of the General Post Office, London, E C
1, do hereby declare the invention, for which I pray that a patent may
be granted to me, and the minethod by which it is to be performed, to
be particularly described in and by the following statement: -
This invention relates to electronic selecting systems and has
particular but not exclusive reference to selecting systems for
automatic telephone exchanges in which a selection has to be made
automatically of a circuit, switch or the like from among a number of
circuits, switches or the like all equally suited to some desired
operation or function of the system.
There are many instances in automatic telephony in which the selection
of one of a number of equally suitable choices is required.
In its most general form, selection in automatic telephone exchanges
involves the selection and rindication of one of a number of marked
circuits in a group of circuits In this specification, time spaced
pulse trains are referred to and it is convenient to describe what is
meant by the terms pulse and pulse trains in this specification A
pulse is a sudden change of current or voltage which lasts for a brief
time period A succession of pulses on one lead equally spaced in time
constitutes a pulse train A group of pulse trains is said to be
equally time spaced if the pulse repetition frequency is the same in
all trains in the group and if the pulses of all the trains in the
group occur at equal time intervals.
Two pulse trains are said to be coincidenst i all the pulses of the
two pulse trains coincide.
Combinations of a plurality of pulse trains all appearing on one lead

such that the time intervals between consecutive pulses aprearing on
the lead are not equal are not to be included in the definition of a
pulse train, but will be referred to herein as combinations of pulse
trains.
The present invention provides an improved system which may be used to
select one circuit out of a number of marked circuits in a group of
circuits.
lPrice 3 s 6 d l According to the present invention a system for the
selection of one of a number of pulse trains from a group of pulse
trains comprises 50 a set of registers, the number of registers in the
set being such that the total number of combinations of registers is
at least equal to the number of pulse trains in the group of pulse
trains each of which is characterisedby 55 a different one of said
combinations of registers, each register being characteristic of a
different combination of pulse trains and being operated by the
application to the register of a pulse of any one of the pulse trains
in the 60 combination of pulse trains, the combinations of pulse
trains being such that for each combination of registers
characterising a pulse train there is only one pulse train which is
unique to that combination of registers, and ' means for applying the
pulse trains from which a selection is to be made to means responsive
to a pulse of one of the pulse trains to operate in the set of
registers that combination thereof characterising the said one 70
pulse train.
The combinations of registers may be taken a fixed number at a time
and such that the number of combinations of registers in the set taken
a fixed number not less than two at 75 a time is equal to the number
of circuits in the group of circuits.
Examples of the systems according to the invention will now be
described in greater detail with reference to the drawings accom 51
panying the specification of Application No.
1684/53, and of which:Fig 1 is a block schematic diagram of one
example;
Fig 2 is a circuit diagram showing part of 85 Fig 1 in logical
symbols; Fig 3 is a circuit diagram of part of Fig 2; Fig 4 shows one
method of deriving pulse trains from which selection is to be made; 90
and with reference to the drawings accompanying the specification of
Application No.
10220/53 of which:Fig 1 shows the waveform of combinations of pulse
trains appearing on the pulse leads of the circuit shown in Figs 2, 3,
4; Fig 2 is a block schematic diagram of another example; Fig 3 is a
circuit diagram of one form ot pulse gate for use in Fig 2; Fig 4 is a
block schematic diagram illustrating one method of deriving a pulse
indication of a selected circuit; Fig 5 is a block schematic circuit

diagram illustrating in more detail the circuit shown schemnatically
in Fig 4; Fig 6 shows in more detail a circuit for obtaining a pulse
indication, and Fig 7 shows in block schematic form a method of
obtaining individual D C indication of selected circuits on individual
leads.
An arrangement for selecting one of a number of circuits markred out
of a group of circuits is shown in Fig 1 of the drawings filed with
Application No 1684/53 This shows a marking lead CT 1 whiich is
provided for one circuit in a group of circuits and which is connected
via a D C suppression gate circuit DSG 1 to a multiplex pulse
generator MX 1 The D C potential of the marlking lead CTI indicates
whether the circuit for which it is provided is among those from which
a selection is to be made Coiresponding leads provided for other
circuits in tie group are also connected to multiplex pulse generator
ivi X 1 which generates on its output lead PLI the pulse trains
ciiatacterising the marked circuits Lead PLI is connected Ars pulse
suppression gate circuit PSG 1 and lead PFLI to selecting means SE Ll
which includes a set of registers One pulse of one pulse train applied
to SE Ll operates a comoinauidon of registers in the set of registers
and this selects one of the marked circuits The selected circuit may
be indica Led by the presence of its pulse train on pulse indicating
lead PIL 1 cr it may be indicated by D C signals on a combination oi D
C indicating leads DAIL of which there is one for each register in the
set.
If a circuit is marked on its indicating lead CT 1 but is nevertheless
not required to be among those from vwhich a seledn is to be made, its
pulse train may be prevented from reaching SE Ll by the applicat'on of
a coincident suppression pulse train on lead PSLI connected to gate
cir:cuit PSG 1, or by the application of a suitable suppressing
potential over a lead such as DSL 1 connected to suppression gate DSG
1 to which lead CT 1 is connected When suitable action has taken place
as a result of such a selection, the operated selecting means may be
released by the application of a releasing signal ove a lead SL 1
which may, for example, be derived using a pulse trigger circuit
operated a fined time after the operation of the registers, or
alternatively which may appear upon the disappearance of the pulse of
the train associated 65,-ith the selected circuit from the pulses on
the common marking lead connected to SE Ll and which occurs after
selection or alternatively the releasing signal may appear upon the
receipt of some suitable releasing signal from some other source 70
The disappearance after selection of a pulse train from the lead PFL 1
may be effected in a manner similar to that described in the
specification of copending Application No 898/53 (Serial No 781,916)
75 Referring now to Fig 2 of the drawings filed with Application No

1684/53, the marking pulse trains of the free marlred circuits are
applied on lead PFL 1 to the blocking device BD 1 which produces a
constant amplitude 80 output for an input greater than a certain
minimum level and also possesses a blocking feature such that after
producing a single pulse of a marking pulse train it is inoperative
for a time This device might be, for example, the o 5 well known
blocking oscillator Its function is to ensure that a single marking
nlse of sufficiently large amplitude is appl ed to the selecting means
to avoid partial operation of the selecting means and hzrea fter to
suppress 90 all pulses that appear on lead PF Ll for a period
sufficiently long to ensure the proper operation of the
selecting-means If for some reason the selecting means are not
operated by the first single marking pulse of a making 95 pulse train
from the blocking device BD 1 then after a given time the blocking
device BDI generates a further single marking pulse, and so on until
registers are orerated.
The output of the blocking device BD 1 is 100 connected by a common
lead CL 1 to a group of coincidence gate circuits such as PCG 1 anrd
PCG 2 asszociated with registers such as REG 1 and REG 2 respectively
The nrumber of r- srers in thne grour is such that the nurberi of 105
combinations of-registers taken not less than two at a time shall be
not less than the number of circuits in the group of circuits.
The coincidence gate circuits are sr' 1 with a combination cf pulse
-rins in a manrner 110 such as that desc-ibed i-;n t s Fpecii Caticn
c' co-pending Patent Application No 598/53 (Serial No 781,916) and:-sh
coincidence gate circuit is associated wiith a register and a second
coincidene gate circuit - vhich -s s 115 plied with the same
combination of pulse trains as the first coincidence gate circuit The
outputs from the second set of coincidence gate circuits are connected
to a further coincidence gate circuit, cemmon to the set and 120 this
further coincidence gbt cri-ut ?od-ces an output wrhen any -o O ' t in
ts are stimulated, w-hich output is coincident -ith the selected
marking pulse train.
In order to make the operation of the select 125 ing means cl-re:, the
selection of one of a group of marlring pulse trains will now be
described in more detail with reference to Fig.
2 For the purposes of this description the pulse train di:-_'iution
will be considered to 130 784,901 784,901 be as coincident pulse
trains on pairs of leads and therefore the registers in the selecting
means will be arranged in one set the number of combinations of
registers in the set taken two at a time being at least equal to the
number of circuits in the group of circuits.
For each selection two of the registers in the set of registers must
be operated.

The marking pulse trains of the free marked circuits are applied on
lead PFL 1 to the blocking device BD 1 which allows transmission of a
single pulse of one of the marking pulse trains on lead CL 1 and
thereafter blocks the transmission of pulses for a period sufficiently
long for the registers to be operated Lead CL 1 is connected to all
the coincidence gate circuits such as PCG 1 and PCG 2 Combinations of
pulse trains which include the marking pulse trains of all the
circuits in the group are applied to pulse leads of which two PL 2 and
PL 3 are shown in the figure For the purposes of explanation the
combinations of pulse trains on lead PL 2 and PL 3 will be -assumed to
include the selected pulse train, one of whose pulses has been
transmitted through blocking device BD 1 The combinations of pulse
trains on leads PL 2 and PL 3 are connected to the coincidence gate
circuits PCG 1 and PCG 2 through delay devices TD 1 and TD 2 which
compensate for delay in the cables and in blocking device BD 1.
Each pulse of one of the marking pulse trains on lead CL 1 coincides
with pulses of the combinations of pulse trains on leads connected to
coincidence gate circuits PCG 1 and PCG 2 which therefore produce an
output to operate registers REG 1 and REG 2 The registers REG 1 and
REG 2 then d c indicate the selected circuit on leads DCIL 1 and DCIL
2 and also operate the gate circuits PG 1 and PG 2 which are connected
to the combinations of pulse trains on lead PL 2 and PL 3.
These combinations of pulse trains include' that of the selected
circuit'so that by connecting the outputs of gate circuits PG 1 and PG
2 to a further coincidence gfate circuit PCG 3 the marking train of
the selected circuit is produced on the lead connected to the input of
amplifier AMP 1, the output of which pulse indicates ithe selected
circuit It is arranged that an inhibiting signal derived, for example,
from the change in potential of the d c indioating leads is applied to
the blocking device BD 1 on lead SL 2, to prevent any further marking
pulses being applied to the registers once the registers have been
operated by a marking pulse Operated registers are restored by means
of an inhibiting signal applied on lead S Li and which may be derived
in the manner described above with reference to.
Fig 1.
The selecting means described in the-present application might for
example take the form shown in Fig 3 of the drawings filed with
Application No 1684/53 For the registers cold cathode gas discharge
tubes V 1, V 2 and V 3 are used The operation of the circuit will be
described considering only the circuits of V 1 and V 2 as being
typical registers in a group of registers 70 Referring now to Fig 2
the input blocking device BD 1 and the coincidence gate circuits PCG 1
and PCG 2 might talke any known form and the operation of the
selecting means will be described from the points where the out 75

puts of coincidence gate circuits PCG 1 and PCG 2 are connected to
registers REGI 1 and REG 2 It will be appreciated that the outputs
from the coincidence gate circuits must be sufficient to operate the
registers when 80 required.
Referring again to Fig 3, V 1 and V 2 will be considered to be the
registers R EG 1 and REG 2 respectively in the selecting means
associated with the selected marking pulse 85 trains When the
selecting means is unoperated, the potential on lead L 3 -connected to
the anodes of the cold cathode tubes is less than that required to
maintain a discharge in the latter Under those conditions a current
flows 90 through resistor R 4, rectifier MR 3 common lead CL 2 and
resistor R 3 towards the source of negative potential -V 1 to which
one end of resistor R 3 is connected This causes the control grid of
valve V 4 to be at a negative 95 potential with respect to earth so
that valve V 4 is non-conducting The rectifiers MR 2, MR 1 and MR 5
are non-conducting so that the combinations of 'negative-going pulse
trains Pl and P 2 applied to capacitors C 1 and C 2, do 100 not appear
on common lead CL 2 The potential of leads DCIL 1 and DCIL 2 is
approximately -V 2.
When a selection is to be made the potential on anode supply lead L 3
is maintained at 105 more than that required to maintain a discharge
in the cold cathode tubes, but less than that required to strike the
said tubes If the cold cathode tubes are then struck by applying a
suitable potential to their strikers, as happens 110 when a pulse
generated by device BD 1 has -' been applied to gates such as PCG 1
and PCG 2, an equal current flows in each of the cold cathode tubes
thus raising the potential of their cathodes and of leads DCIL 1 and
115 DCIL 2 The current through tube V 1 flowing through resistor R 2
and rectifier MR 1 is just sufficient when flowing through resistor R
3 to raise the potential of common lead CL 2 to earth potential thus
causing valve V 4 to 120 conduct The equal current from tube V 2
causes rectifier MR 2 to conduct and carry this current It will be
seen that the initial pulses due to the striking of V 1 and V 2 have
brought V 4 to a state of readiness 125 A negative going pulse of the
combination of pulse trains Pl applied to capacfitor C 1, occurring at
a time when no pulses of the combinations of pulse trains P 2 is
present on C 2, will bias rectifier MR 1 to its non-conduct 130 784,90
ing state for the duration of the pulse, so preventing the passage of
current from tube V 1.
The current flowing in rectifier MIR 2 will also cease for the
duration of the pulse but the potential of lead CL 2 remains unchanged
at earth potential, the current in resistor R 3 being maintained by
that flowing through tube V 2 If a pulse of a combination of pulse
trains P 2 applied to capacitor C 2, occurs at a time when no pulse

from a combination of pulse trains Pl is present on C 1 a similar
rearrangement of currents flowing, takles place and the potential of
lead CL 2 remains at earth potential However when pulses from
combinations of pulse trains Pl and P 2 coincide the currents flowing
in rectifier MR 2 and resistor R 2 are no longer maintained and the
potential of common lead CL 2 falls towards -V 1 cutting off the anode
current of valve V 4 for the duration of the coincident pulses In this
manner coincident pulses of the combinations of pulse trains Pl and P
2 are caused to appear on common lead CL 2 and to be amplified by the
two stage amplifier composed of valves V 4 and V 5 coupled together by
transformer TR 1 The output is taken from the secondary of-transformer
TR 2 The potential on lead L 3 is lowered to extinguish the cold
cathode tubes The extinguishment of tubes V 1 and V 2 has no effect
since the time constants of the circuit are such that the potential of
lead CL 2 returns very slowly from earth potential to its initial
negative potential.
Thus, if means already described are caused to strike two of the cold
cathode tubes in the group of cold cathode tubes, then the marking
pulse train of the selected circuit is generated and the selected
circuit is indicated by means of d c potentials on combinations of
leads such as DCIL 1 and DCIL 2.
A means for generating the marking pulse trains i e the means
indicated at Ml X 1 in Fig.
1, might, for example, take the form shown in Fig 4 of the drawings
filed with Application No 1684/53 Leads A, B, C, D and E carry
combinations of pulse trains arranged as described in the
specification of co-pending
Patent Application No 898/53 (Serial No.
781,916), so that any of the pulses may be made effective by
connecting a suitable combination of pulse leads to a coincidence gate
circuit.
The pulse trains on the group of pulse leads A, B, C, D and E are
arranged so that if the leads are required to be connected to
coincidence gates two at a time any of the pulses may be made
effective in any of the gate circuits.
It is convenient, instead of using individual coincidence gates for
each circuit, to use two stages of modulation to produce the
respective pulse trains which are coincident in the various pairs of
leads In the first stage of modulation, operating leads are each
connected to a coincidence gate circuit each of which has connected to
it one of the pulse leads in the group of pulse leads These first
stage coincidence gate circuits are arranged in groups such that no
pulse lead is connected to more than one coincidence gate circuit in
each group The outputs from all the gates in each group are 70 then

commoned and each common lead is connected to a coincidence gate
circuit in the second stage of modulation Each second stage gate
circuit has connected to it one of the pulse leads in the group of
pulse leads, 75 this pulse lead being one not already in use in the
associated group of first stage gate circuits.
If the outputs of a number of such second stage groups of coincidence
gates are combined onto a common lead then by a suitable 80
arrangement of pulse leads any of the marking pulse trains may be
produced on that common lead by stimulating the appropriate operate
lead or leads, In Fig 4 coincidence gate circuits PCG 4 85 and PCG 5
form a first stage group, and are connected to a second stage
coincidence gate circuit PCG 9 First stage coincidence gate circuits
PCG 4 and PCG 5 are connected to pulse leads B and E respectively and
the second stage 90 coincidence gate circuits PCG 9 is connected to
pulse lead A Thus second stage -coincidence gate circuit PCG 9 will
provide for the combination of pulse leads A and B, and A and E, when
operating leads L 4 ahd L 5 are 95 respectively stimulated The first
stage group could include two more coincidence gate circuits having
pulse lead C connected to one and pulse lead D connected to the other
so that the second stage gate circuit PCG 9 could pro 100 vide all the
combinations of the other pulse leads taken one at a time with pulse
lead A.
First stage coincidence gate circuits PCG 6, PCG 7 and PCG 8 are
connected to poulse leads, C, D and E respectively and to second 105
stage gate circuit PCG 10 to which is connected pulse lead B and these
coincidence gate circuits can provide on the output of s'cond stage
gate circuit PCG 10 all the combinations of the pulse leads C, D and E
feeding the 110 first stage group, taken one at a time with pulse lead
B The outputs of the two second stage gates PCG 9 and PCG 10 together
with those of further second stage gate circuits each fed with a
different pulse lead in the -c-'r of 115 pulse leads, are commoned
onto u lead CL 3, which is connected to amplifier AMP 2 Ar ro' the
marking pulse trains may be produced from the output lead PL 4 of
amplifier AMP 2 by stimulating the appropriate operate lead For 120
example, stimulating operate lead L 4 produces on lead PL 4 the
marking pulse train that appears on both pulse leads B and A or
stimulating L 6 produces the marking pulse train that appears on both
pulse leads B and 125 E and so on for the other marking pulse trains.
In Fig 2 of the drawings there is shown a method of obtaining a pulse
indication of a marked circuit This is achieved bv means including
coincidence gates such as PCG 1 and 130 : 1:784,901 5 PCG 2 of that
figure which are operated by an output pulse from the blocking
oscillator BD 1 and coincidence pulses on the pulse leads PL 2 and PL
3 Instead of the marking pulse trains being generated coincidentally

on a combination of a fixed number of pulse leads the combinations of
pulse trains may take another of the forms described in the
specification of copending Application No 898/53 (Serial No.
781,916) In that form each pulse train in a set of pulse trains is
generated on one pulse lead or coincidentally on a combination of
pulse leads individual to it The combinations of pulse leads are not
restricted to a fixed number of pulse leads.
Thus using "n" registers with their associated coincidence gates and
pulse leads 2 n-1 different combinations may be used and each may be
associated with a different circuit in the group Fig 1 of the drawings
filed with Application No 10220/53 shows an arrangement of 7 pulse
trains P 1-P 7 on combinations of 3 pulse leads P Lll, PL 13, PL 14
which may correspond to the pulse leads shown in Fig 7 of the drawings
accompanying the specification of co-pending patent Application No.
898/53 (Serial No 781,916) Fig 2 of the drawings shows an arrangement
whereby these three pulse leads may be used in an embodiment of the
present invention to select one circuit out of a number of marlred
circuits in a group of 7 circuits.
Fig 1 of the dr awings filed with Application No 10220/53 shows how
the 7 pulse trains P 1, P 2 P 7 may be arranged on pulse leads PL Il,
PL 12 and PL 13 so that each appears on a single lead or on a
combination of pulse leads individual to it Thus P 1, P 2 and P 3
appear on one lead each, P 4, P 5 and P 6 appear on different
combinations of the pulse leads taken two at a time and P 7 appears on
all three pulse leads Clearly there are many similar ways of arranging
the 7 pulse trains on the three pulse leads such that each appears on
a combination individual to it In fact there are /7 ways of so
arranging them.
Fig 2 of the drawings filed with Application No 10220/53 shows seven D
C marking leads CT 1, CT 2 CT 7, one for each circuit of a group of
circuits from which a selection may be made These seven marking leads
are connected to D C suppression gate DSG 1, DSG 2 DSG 7 to which D C
suppressing leads DSL 1, DSL 2 DSL 7 are connected whereby the D C
marking signals on some or all of the circuits may be removed.
The outputs of DSG 1, DSG 2 DSG 7 are connected to pulse gates PG 1,
PG 2 PG 7 to each of which pulse leads P Lll, PL 12 and PL 13 are
connected Each gate is arranged so that on 6 or more of the pulse
leads act as operating leads the pulses on these leads acting as
operating stimuli and the remainder as inhibiting leads the pulses on
these leads acting as inhibiting stimuli and such that the operatLing
lead or the combination of operating leads applied to each gate is
individual to it Thus the operating lead connected to PG 1 is PL Il
only; to PG 2 is PL 12 only; to PG 3 is PL 13 only; PL 12 and PL 13
are operating leads for' 70 PG 4; P Lll and PL 13 for PG 5; P Lll and

PL 12 for PG 6 while P Lll, PL 12 and PL 13 are operating leads for PG
7 In each case the remaining pulse leads, if any, are connected to the
gate as inhibiting leads The opera 75 tion of each is such that when
the marking signal is applied to the gate the pulse train appearing on
the operating lead or coincidentally on all the operating leads but on
none of the inhibiting leads applied to that gate 80 then is
transmitted to the output lead PL 1 common to all seven gates With the
arrangement of pulse trains and pulse leads shown in Figs 1 and 2
pulse trains P 1, P 2 P 7 are controlled by leads CT 1, CT 2 85 CT 7
respectively It will be appreciated that the pulse leads PL 11-13 and
pulse gates PG 1-7 replace the multiplex MX 1 shown in Fig 1 of the
drawings accompanying Application No 1684/53 The gate circuits may
corn 90 prise for example rectifier gate circuits of the type shown in
Fig 3 of the drawings filed with Application No 10220/53 in which case
each pulse train combination is generated for example using a phase
reversing pulse trans 95 former, on two leads one for each polarity of
the pulses.
Fig 3 of the drawings filed with Application No 10220/53 shows a
possible circuit for the gate PG 1 It comprises a resistor R 1 connec
100 ted between point X which is near earth poten tial and a negative
supply voltage such that a current I flows through R 1 The point X is
connected via rectifier W 1 to earth so that if the current flowing
into point X exceeds I the 105 potential of X is clamped just above
earth, by the low resistance of rectifier W 1 The potential of point X
can only fall below earth when there is insufficient current flowing
into point X to keep rectifier WI 110 conducting in its forward
direction The marking lead CT 1 is connected via rectifier W 2 to
point X and when the circuit for which the gate is provided is
unmarked a current greater than I flows through rectifier W 2 keeping
point 115 X substantially at earth When the circuit is marked, the
potential of lead CT 1 falls and rectifier W 2 is backed off Lead DSL
1 is connected via rectifier W 3 to point X and if the associated
circuit is unsuitable for selection 120 the positive potential of lead
DSL 1 may cause a current greater than I to flow through rectifier W 3
thus again keeping rectifier W 1 conducting If the circuii is suitable
for selection the negative potential of lead DSL 1 keeps rec 125
tifier W 3 backed off The inhibiting pulse leads, in this case leads
PL 12 and PL 13, upon which positive versions of the pulse trains
appear are connected via rectifiers W 4 and W 5 so that if a pulse
appears on lead PL 12 or 130 l 784,901 PL 13 a current greater than I
flows through rectifier W 4 or W 5 keeping point X at earth.
Each of the operating pulse leads, in this case P Lll, only is
connected via a capacitor Cl to the junction of a resistor R 2
connected to a positive potential supply and a rectifier W 6 connected

to point X such that a current greater than I normally flows through
resistor R 2 and rectifier W 6 to point X-keeping rectifier W 1
conducting The negative going pulses applied on lead P Lii back off
rectifier W 6, point X is also connected -via rectifier W 7 and
resistor R 3 in series connection to earth Only when rectifiers W 2, W
3, W 4, W 5 and W 6 are all backed off does rectifier W 1 become
backed off and the potential of point X falls below earth causing a
pulse of amplitude approximately I R 3 to appear across resistor R 3 _
which may be common-to a number_ of gates The_ circuit comprising
resistor R 2, capacitor C 1 and rectifier-W 6 may be repeated for
other circuits associated withcombinations of two or more operating
pulse leads Referring again to Fig 2 of the drawings fied with
Application No 10220/53 the pulse trains of all the marked circuits
suitable for selection appear-on-lead PL 1 connected to PSG 1, -in
which the circuits unsuitable for selection may be pulse deleted by
the application of coincident pulse trains of PSL 1 The output of PSG
1 is connected to blocking device BD 1, which, when a selection-is to
be-made responds to -one applied pulse and generates on its-output a
pulse which is applied to the coincidence gates PC Gl, PCG 2-and PCG 3
to which versions of -PL 11, PL 1 Z and PL 13 are applied respectively
on leads P Ll', PL 12 ' and PL 131 PL 1 l PL 12 and PL 13 are
connected via delay networks DJ, D 2 and D 3 respectively to leads P
Lli', PL 12 and PL 131 respectively in order to compensate for the
delays in transmission through and may be-in the operation of BD 1
which may be the well known blocking oscillator If a pulse of- Pl is
generated -by BD 1 the pulse coincides in PCG 1 with-a pulse on P Lll
and is transmitted to operate REG 1 using techniques, for example, as
described in Specification No 722,179 Similarly the operation of BDI
by pulses of other trains will cause other combinations of registers
to become operated and the operated registers may D C.
indicate the selected circuits on the -output leads DCIL, DCIL 2 and
DCIL 3 some cornmbination of which-will indicate the operated
condition when a selection has been made The fact that a register has
been -operated is also indicated on suppression-lead SL 2 applied-to
BD 1 preventing it from-generating any further pulses on its output
After appropriate action has-taken place a signal -on suppression lead
SL 1 may be used to 'restore the registers to normal This signal may
be derived in the manner: -described above.
The selected pulse trains may be caused to disappear from lead PFL 1
in a manner similar to that described above.
Fig 4 of the drawings filed with Application No 10220153 indicates in
a general manner only the technique of obtaining a pulse indi 70
cation of the selected circuit The D C indicating leads DCILI, DCILZ
and DCIL 3 are connected to a unit GUI to which the associated pulse

leads P Lll, PL 12 and PL 13 are also connected Unit GU 1 transmits
only those 75 pulses appearing on all the pulse inputs which are
associated with operated registers Thus if REG 1 is the only register
to be operated P 1, P 5, P 6 and P 7 all appear on the output of PC
Gll whereas if REG 2 and REG 3 are both 80 operated, P 4 and P 7
appear on the output of GU 1 which is connected to the input of
suppression gate PS Gll DCIL 1, DCIL 2, DCIL 3 are also connected to
suppression gates SG 1, SG 2 and SG 3 respectively to which P Lll, 85
PL 12 and PL 13 are respectively connected and whose outputs are all
connected to suppression lead SL 1 L on which appears the pulse trains
of circuits associated with registers not -operated by the output from
BD 1 Thus if 90 REGI is the only operated register, all the pulse
trains on PL 12 _and PLI 3 appear upon SL Il Similarly if DCIL 2 and
DCIL 3 are in their operated state all the pulse trains on P Ll appear
upon S Lll and this lead is con 95 nected to PS Gll and pulses on the
output of PCG 11 are suppressed in PS Gll by coincident pulses on S
Lll Thus on PI Ll appears only the pulse train of the circuit
associated with the operated combination of registers that 100 being
the only pulse train appearing on all the pulse leads associated with
operated registers and none of the others, and it is the pulse train
characterising the selected circuit Fig 5 of the drawings filed with
Application 105 No 10220/53 shows a-more exact representation of the
techniques illustrated in Fig 4 of these drawings Fig 5 shows one of
the D C.
indicating leads DCIL connected to two suppression gates SG 21 and SG
22 to both of 110 which the associated pulse trains are applied over
lead PL In SG 21 the pulse trains inter-.
rupt the stimulus applied to DCIL where its associated register is
operated and a stimulus therefore appears upon its output provided the
115 associated register is operated and except during the pulses of
the associated pulse trains.
The outputs of this and other similar gates -provided for other
registers are connected by a common lead to a suppression gate SG 23
to 120 which a D C source is connected and which is interrupted by the
stimuli from SG 21 and like gates On the output of SG 23 appear only
those pulse trains appearing on all the pulse leads associated with
operated registers These 125 are applied to a pulse suppression
gate-PSG 11 -as in Fig 8 in which the pulses associated with
unoperated registers are deleted by pulses on SL 11 connected to the
outputs of SG 22 and like suppression gates -in which the applied 130
: 6 tors R 14 and R 15 in the intervals between the pulses and is
discharged during the pulses via rectifiers W 12 and W 15 Since no
registers are operated rectifier W 14 will be conducting and, valve V
2 cut off at the control grid 70 and the small amplitude pulses

transmitted to point Y via capacitor C 13 will have not caused valve V
2 to conduct.
When a combination of registers is operated current flows through the
operated cold 75 cathode tmyratrons and, assurmung valve V 1 is anmong
tiose operated a current greater than I flows Trough resistor k 12
which causes rectifier W 11 to conduct except during the negative
going pulses applied via capacitor 80 C 12 The current flowing into
point I trom the operated registers will cause capacitor C 13 to
cnarge up via rectifier 5 Wi such that the point Y is normally at
earth causing rectifier W 13 to conduct Only when coincident pulses
are 85 applied to all the operated registers will point Y tend to go
negative due to the current I flowing ini resistor R 17 and then only
if no positive pulse is applied to point Y, via capacitor C 13 For the
operated registers the dis 90 charge current will back off the
rectifiers such as W 12 such that the positive pulses appearing at
point Q are only those associated with inoperated registers A pulse
appearing at point Q coinciding with coincident pulses of 95 the
operated registers will cause a current I flowing through resistor R
17 to charge capacitor C 13 which will keep point Y at earth potential
'This is discharged during the intervals between pulses by some oi the
current 100 flowing into point Y from the operated registers When a
negative pulse is appiied coincidendy via capacitor C 12 for all
operated registers which does not coincide with any of the positive
pulses supplied to unoperated 105 registers the point Y will move
negatively taking point Q with it thus causing a negative pulse to be
applied to the control grid of valve V 2 causing an output pulse to
appear on the output lead PI Ll of the transformer coupled 110
amplifier of which valve V 2 is the first stage.
Thus only those pulses associated with all the operated registers and
with none of the unoperated registers will appear on lead PILI and
these will constitute the pulse train charac 115 terising the selected
circuit The condition for the satisfactory operation of the circuit
shown in Fig 6 is that the current taken by the operated registers
should be at least twice the current I and that the current taken
through 120 resistor R 14 when valve V 1 is unoperated should be at
least half I with the pulses shown in Fig 1 of the drawings filed with
Application No 10220/53.
When any register becomes operated the 125 point Z will become more
negative and this may be used to prevent the further operation of the
blocking device BD 1 over lead SL 3 or alternatively the D C
indicating leads DCIL or DCIL' may be commoned via suitable 130 pulse
trains on PL are suppressed when theassociated register is operated.
Fig 6 of the drawings filed with Application No 1022/53 shows one
register comprisiug a cold cathode tube Vi winch may be operated by

applying a suitable potential to the striker The catoiode is connected
to a negative supply voltage via resistor R 11 and via a seconc
resistor R 12 and a rectifier Wi 1 to a point V which is near earth
potential and wnich is common to all the registers in the set When
valve V 1 is unoperated the rectifier W 11 is backed olf and the
cathode D C indicating lead DCIL is near the negative supply voltage
The point Y is connected via rectifier W 13 to earth and via resistor
R 17 to a negative, supply sufficiently negative for a substantially
constant current I to flow through it throughout the operation of the
circuit If so the current flowing to the point Y exceeds I the excess
current causes rectifier W 13 to conduct in its low resistance
direction and point Y is substantially at earth Point F is also
connected via rectifier W 14 to the grid of a triode V 2 whose cathode
is earthed and via a resistor R 18 connected to a voltage supply just
below earth With no other current flowing into the point Y, the
current I is drawn through rectifier W 14 in its low resistance
direction and through resistor R 18 such that the grid of valve V 2 is
just beyond cut off.
With a current greater than I flowing into point Y and with rectifier
W 13 conducting, rectifier W 14 is backed off and valve V 2 is
conducting.
The anode of valve V 1 is connected to the anode D C indicating lead
DGIL 1 and via a resistor R 13 to a second resistor R 14 and thence to
a point Z common to all the registers.
Point Z is connected to a control lead L 1 via a resistor R 15 which
except during tic nc malising of the registers is at a positive
potential Tle junction point of resistors R 14 and R 13 is connected
via rectifier W 12 to a point Q common to all registers and Q is
connected via rectifier W 15 to a second positive potential which is
say, 50 volts below that of lead SL 3.
The points Q and Y are connected together via capacitor C 13 which
performs the functions of SL 1 l in Fig 4 and Fig 5 of the drawings
filed with Application No 10220/53 Positive and negative versions of
the pulse trains associated with V 1 are connected via capacitors Cli
and C 12 respectively to the junction of resistors R 13 and R 14 and
to the junction of resistor R 12 and rectifier WII respectively.
Before a selection is made none of the registers is operated and for
each register the positive pulse trains applied via C 11 cause
rectifiers W 12 and W 15 to conduct at the peaks of the applied pulses
such that during the intervals between the pulses of the register
rectifier W 12 is backed off and during the intervals between all the
pulses applied to all the registers rectifier W 1 S is also backed
off.
The capacitor C 11 will charge through resis784,901 784,901 decoupling

means onto lead SL 2 used for this purpose The registers may be
released by applying a negative pulse of appropriate length to the
lead SL 3 derived for example in a manner similar to that of the
releasing signal described above with reference to Fig 2 of the
drawings filed with Application No 10220/53.
Fig 7 of the drawings filed with Application No 10220/53 shows in
logical f -rm how individual D C indications may be derived so that
the selected circuit may be D C indicated on a lead individual to it
It showvs 7 gates DCG 1 DCG 7 to which all the D C.
indicating leads are connected either as operating or inhibiting leads
as already described for the mardking pulse multiplex and in which it
may be convenient to use both the phases shown in Fig 7 as DCIL and
DCIL 1 one for the operating stimulus and one for the inhibiting Onr
one of the output indicating leads DCIL 11 DCIL 17 will appear the
indication of the selected circuit The circuits used for these gates
may take any of many well known forms.
It will be clear that only one method of carrying the invention into
effect has been described and that there are many alternative ways of
using it For example all the combinations of registers would not be
use if some of the pulses on the pulse distribution leads were
omnitted Also the invention finds application in any system involving
selection processes and although it has been here described in
relation to the selection of circuits, the selector described may be
used for the selection of anything provided that a pulse train may be
generated for each thing when it is suitable for selection.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB784902 (A)
Description: GB784902 (A) ? 1957-10-16
Improvements in or relating to alkaline electric accumulators

BE520658 (A) CH318586 (A) DE1055629 (B) FR1078148 (A)
BE520658 (A) CH318586 (A) DE1055629 (B) FR1078148 (A) less
784,902 112 ' Date of Application and filing Complete Specification
June 18, 1953.
-z -; No 16926/53.
Application made in Germany on June 23, 1952.
Index at Acceptance:-Class 53, B 51 (A 16: Bl X: D 3: E 1 B: E 1 C: E
2), B 53 A 1.
International Classification:-Holn L COMPLETE SPECIFICATION in or
Relating to Alkaline Electric Accumulators We, ACCUMULATOREN-FABRIK
AKTIENGESELLSCHAFT, a German Company, of Dieckstrasse 42, Hagen,
Westfalen, Germnany, do hereby declare the invention, for which we
pray that a patent may be granted to us, and the method by which it is
to performed, to be particularly described in and by the following
statement: -
This invention relates to alkaline electric accumulators.
The capacity of an accumulator increases as the electrode surface is
increased assuming that the active material content remains constant
Such an increase in the surface area of the electrodes is necessarily
accompanied by a reduction in the thickness of the electrodes It is,
however, difficult to manufacture the usual alkaline accumulators with
pocket-type electrodes, in which the electrodes have a large surface
area and are consequently very thin, because it is difficult to
introduce very thin layers of active material into the pockets in a
manner such that none of the active material drops out of the
perforated pockets and is lost in the course of the assembly and
during operation of the accumulator.

On the other hand, very thin electrodes using highly porous sintered
bodies as the carriers for the active material have been used in
alkaline accumulators and have proved particularly advantageous The
positive or negative active material, introduced by way of
impregnation into the sintered body, remains securely lodged within
this body and cannot drop out and so be lost, because the pores are
very much finer than the orifices of a pocket-type electrode With a
thin electrode, a certain quantity of active material is accessible to
the electrolyte over a large area, and therefore some of the
characteristics which tend to lower the electromotive force, such as
internal resistance and polarization, are considerably reduced and
a-greater proportion of the active material is lPrice 3 s 6 d l
utilised, that is to say the potential utilisation of the active
material, and specific load A/sq dm are considerably improved in
comparison with the usual pocket, tube and folded-band constructions,
and in com 50 parison with sintered constructions of the hitherto used
accumulators having thicker electrodes.
However, thin sintered bodies have very low mechanicial strength and
are, therefore, 55 ill-suited for use without a metal stiffener or
support If such thin electrodes are made in the usual manner, there is
no connection or only an indifferent connection between the supporting
and the sintered body, so that the 60 electrode is not durable in that
it is stisceptible to damage and the sintered body may become detached
from the support.
If it is desired to make a useful, extremely thin electrode of which
the carrier for the 65 active material is a sintered body having a
thickness of not greater than 1 mm, a firm contact between the
sintered body and the support must be provided To achieve this, it has
been proposed to produce on the metal 70 sheet serving as the support
for the sintered body a sintered layer of metal on one or both sides
at an elevated temperature and only then to deposit thereon the porous
sintered body proper which is to carry the active 75 material This
method has the disadvantage that the intermediate sintered layer
preliminarily produced on the metal sheet is of low porosity so that a
considerable portion of the sintered body is left incapable of accom
80 modating active material.
It has been further proposed to produce a rough or porous metal layer
on the metal support by applying to it, advantageously by spraying, a
suspension of a metal powder in 85 a varnish or other liquid so that,
during a subsequent annealing operation carried out in a reducing
atmosphere at a very high temperature, the metal powder is sintered
with the metal support However, even in this 90 "W 2 f i, crw
improvements manner a metal layer of low porosity is obtained which
suffers from the same disadvantage as mentioned in connection with the

above method Moreover, this process is rendered more expensive by the
necessity of using bonding agents and solvents.
Nor can the recently proposed sintering of a base metal power on the
metal support and subsequent galvanization produce the desired effect,
since galvanization levels out and smooths the previously roughened
surface, so that firm cohesion between the porous sintered body and
the metal support is not obtained.
British patent specification No 695,854 describes and claims an
electrode for alkaline secondary batteries with a porous sintered body
serving as a materials carrier sintered on to a support, in which the
support, in whatever form, is superficially roughened without being
subsequently electro-plated, whereby a surface layer is produced to
which the porous sintered body of the electrode firmly unites in the
usual sintering process.
The present invention provides a process for the manufacture of an
electrode for an alkaline accumulator which comprises forming on the
surface of a metallic support a porous layer of conducting material
which adheres to the said support and of which the free surface is
rough, and sintering to the said porous conductive layer a porous
metallic sintered body which, together with the said' layer, serves as
the carrier for the active material of the electrode, the thickness of
the carrier being not greater than one millimetre.
Several methods of producing an electrode in accordance with the
invention will now be described in greater detail by way of example.
In one method, a support is first dusted with a metal powder so that a
layer is produced of which the thickness is approximately' equal to
the diameter of one particle and which is such that the particles do
not form a continuous layer When this combination is subjected to a
sintering process under the usual conditions in a reducing atmosphere,
it is transformed into a roughened layer which adheres to the support
and forms a rough surface In this method, the desired roughness of the
surface of the support is produced by the firmly adherent metal powder
between which some sections of the initially smooth surface of the
support are still noticeable as depressions.
Metal powder is then distributed over this roughened metal surface and
sintered to form, together with the roughened layer already adhering
to the metal support, a highly porous sintered body, which is capable
of carrying the active materials throughout its thickness.
In a similar manner there may be produced a rough surface on the metal
support by means of a sprayed-on metal mist which is sprayed on to the
surface of the support to form a highly porous extremely thin layer,
70 a metallic contact being achieved at the same time.
Alternatively, the roughening of the carrier surface and the
production of the highly porous, thin sintered body to carry the

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