5161 5165.output

* GB785568 (A)
Description: GB785568 (A) ? 1957-10-30
Improvements in or relating to frequency divider circuits
Description of GB785568 (A)
A high quality text as facsimile in your desired language may be available
amongst the following family members:
DE1034217 (B)
DE1034217 (B) less
Translate this text into Tooltip
[79][(1)__Select language]
Translate this text into
The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PATENT SPECIFICATION
785,568 Date of Application and filing Complete Specification Sept 16,
1955.
No 26561/55.
Application made in United States of America on Sept 17, 1954.
Complete Specification Published Oct 30, 1957.
Index at Acceptance:-Class 40 ( 6), G( 1 G: 2 A), P( 1 F: 1 M 3: 1 U:
2 A: 2 D: 4 R).
International Classification: -H 03 k.
COMPLETE SPECIFICATION
Improvements in or relating to Frequency Divider Circuits We, WESTERN
ELECTRIC COMPANY, INCORPORATED, of 195, Broadway, New York City, New
York State, United States of America, a corporation of the 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 electrical circuits
for effecting frequency division.
In electronic computers and similar electrical information systems, a
source of base or clock frequency is often provided This clock
frequency serves to define the time intervals of the information
digits and to synchronize the various operations of the system
Additionally, however, it is necessary to provide a number of control
signals In serial digital computers repetitive operations are often
performed at a submultiple of the basic clock signal or frequency The
initiation and synchronization of various computer operations
accordingly depends on the availability of these single pulses
occurring cyclically at predetermined intervals These intervals may be
of the order of once every ten, hundred, thousand, or even millions of
cycles of the clock frequency The generation of cyclically occurring
pulses at a frequency which is a submultiple of the clock frequency
has been termed frequency division.
It is a general object of this invention to provide improved circuits
for frequency division.
According to the invention there is provided a frequency divider
circuit comprising means for transmitting a single pulse at intervals
of N digits of a clock frequency, an adder circuit, means for applying
the single pulses to the adder circuit, means connecting the output of
said adder circuit to the input thereof, said connecting means having
a delay of n/k digits, where k is any positive number, and gate means
for transmitting an output pulse only on occurrence of a pulse from
said transmitting means and from said adder circuit on lPrice 3 s 6 d
l accumulation of a predetermined number of pulses in said connecting
means.
In one specific embodiment of this invention, a large frequency
division is attainable by employing two stages of frequency division.
The first stage comprises a delay line register in which a single
pulse is stored and circulated, apearing at the output once every a
digits or cycles of the clock frequency The frequency division of the
first stage is l/n of the clock frequency The second stage comprises a
binary half adder with a delay line having an accumulation of N digits
'of the clock frequency and a gating circuit The single digit
transmitted by the first stage circuit is counted by the second stage
circuit until the half-adder delay line is full, at which time the
gating circuit is enabled and a single pulse applied to the output
lead The frequency division of the second stage is 1/2 N of the clock
frequency and thus the overall frequency division is 1/(n) ( 2 a) of
the clock frequency.
Generally in such computers N digits would define the word or
information message.

Accordingly, we can consider that the first stage of frequency
division divides the clock frequency to the word frequency and the
second stage of frequency division affords an output control pulse at
some submultiple of the word frequency.
The first stage division may be attained advantageously by a number of
delay line register circuits, the various delay lines providing
different delays The number of digits delay of the various lines
should be relative primes or products thereof with respect to each
other The outputs of the various single circuits are applied to an AND
logic gate so that a pulse is transmitted to the second stage of
frequency division only on the occurrence of outputs at all the angle
circuits in the first stage.
If it is desired to trigger the first stage of frequency division by a
train of pulses at the clock frequency, rather than by a single
initiating pulse, the first stage division may be attained
advantageously by a number of delay 785,568 lines connected between
the output and one input of an inhibitor circuit, the train of clock
pulses being applied to the other input of the inhibitor circuit.
Additionally, the second stage of frequency division may include
circuitry for repeating the single output pulse for exactly one half
the cycle between output pulses, when it is desired to obtain a
sinusoidal or other cyclical wave of the lower frequency.
The frequency divider may also have preset therein a number so that
the frequency division attained by the second stage circuit is 1/l 2
u-(preset number)l of the zword frequency As the preset number may be
any number from 0 to 27 the second stage of frequency division can
attain any desired division of the word frequency As the input pulses
to the second stage of frequency division need not in all cases define
word frequency or word repetition rate, we can state that by
presetting a number in a frequency divider circuit in accordance with
this invention, any frequency division of the input pulses may be
obtained provided that the frequency of the input pulses is smaller
than the clock frequency which defines the digit intervals of the
circuit.
A complete understanding of this invention may be gained from
consideration of the following detailed description and the
accompanying drawings, in which:Fig 1 is a simplified block diagram of
one specific illustrative embodiment of a two stage frequency divider
in accordance with this invention; Fig 2 is a more detailed block
diagram of the embodiment of Fig 1; Fig 3 is a pulse-time chart
depicting the occurrence of pulses at various points in the emobdiment
of Fig 2; Fig 4 a is a block diagram of the embodiment of Fig 2
modified to include the amplifiers and inherent delays therein; Fig 4
b is a schematic diagram of the embodiment of Fig 4 a; Fig 5 is a

block diagram of another specific illustrative embodiment of a first
stage frequency divider in accordance with this invention; Fig 6 is a
block diagram of another specific illustrative embodiment of this
invention wherein the second stage of frequency division is preset;
Fig 7 is a block digram of another specific ilustrative embodiment of
this invention wherein the output is not a single pulse but a train of
pulses occurring for one half the period of the output frequency of
the second stage circuit; Fig 8 is a pulse-time chart depicting the
occurrence of pulses at various points in the embodiment of Fig 7; and
Fig 9 is a block diagram of another specific embodiment of a first
stage frequeaczy divider in accordance with this invention.
Turning now to the drawing, the illustrative embodiment of the
invention depicted in Fig 1 accords a frequency division oi
substantially 1/(n) ( 2 '1), where it is any digit A single pulse is
applied, from a single pulse generator 70 10, to a delay line register
frequency divider 11, which provides a recurrent output pulse once
every n E digit This output 's arpl-td to a second stage of frequency
division including an adder circuit 12, which may be either a 75 full
or half-adder circuit The adder output is connected through an N digit
delay line 13 back to the input of the adder circuit When the N digit
delay line 13 is filled, i e, when sufficient digits have been added
so that the 80 ouput of the adder is a succession of N pulses, a gate
14 is enabled and a single output pulse appears on an output lead 16
The adder circuit is also reset to begin the next cycle of frequency
division on receipt of a pulse from 85 the first stage frequency
divider 11.
Accordingly, in the general combination of the specific embodiment of
the invention there is a first stage of frequency division, attained
by the employment of a delay line register 90 circuit, and a second
stage of frequency division, attained by the employment of circuitry
for the accumulation of pulses from the first stage Fig 2 depicts one
specific embodiment, in block diagram form, of the embodiment of 95
the invention of Fig 1; an understanding of this embodiment can be
gained from a consideration of its operation together with the
pulse-time chart of Fig 3 In this embodiment it is assumed that n= 4
and that the desired 100 frequency division is 1/( 4) ( 21) or 1/64 of
the clock frequency which may be of the order of 3 megacycles.
In Fig 3 are depicted the pulses occurring at different points in the
circuit of Fig 2 dur 105 ing the operation of that circuit; the points
are labelled It, b, c, d, e, f, g, h, k, and i and will be further
identified in the description of the circuit The base or clock
frequency is also shown on Fig 3, although it does not appear 110
explicitly in Fig 2 However, it is to be understood that clock signals
are applied to various components, such as amplifiers, within the

circuit, as more clearly seen in the circuit schematic of Fig 4 The
pulses occur dur 115 ing the positive cycles of the clock frequency
and in synchronism therewith; the clock frequency thus defines the
digit intervals of the circuit.
The initiating pulse from the single pulse 120 generator 10 is applied
to the first stage frequency divider 11; the initiating pulse occurs
at point a and the output of the first stage frequency divider 11,
which occurs at point b, is a train of pulses, one pulse appearing for
each 125 four cycles of the clock frequency as we have assumed, in
this embodiment, that n= 4 The train of pulses b is applied through an
OR circuit 18 to a half-adder circuit 19 A half adder is a circuit,
known in the art, which has 130 785,568 an output on a first lead if
one of two but not both, inputs is present and an output on a second
lead if both inputs are present The first of these outputs, usually
referred to as the sum output, appears at point c and the second,
usually referred to as the carry output, at point e The sum output at
c are trains of pulses representing successive binary digits from 1 to
2 ", which in this embodiment is from 1 to 16.
To facilitate an understanding of the time chart of Fig 3 the decimal
equivalent of each binary number is indicated on the drawing.
The pulses appear in the four digit time slots or intervals defined by
the clock frequency.
For larger values of N there would of course be more time slots
defined between successive pulses at point b and the outputs at point
c would include binary nlumbers 'cf a larger number of digts.
The pulses appearing at point c are passed through a delay line 21,
which advantageously has N digits of delay, and then applied as the
second input, at point d, to the halfadder circuit 19 The input at
point d is thus the output at point c delayed by four digits of the
clock frequency In the overall system four digits would probably
represent one word or information message unit When a pulse at b and a
pulse at d coincide, the output of the half-adder 19 is a pulse at
point e, instead of at point c; this pulse at point e is a carry pulse
and is passed through one digit of delay, by a delay line 22, to the
OR circuit 18 The delayed pulse from point e applied to the OR circuit
18 appears at point f.
We can thus now state the conditions for operation of the half-adder
circuit 19; these are: an output appears at c if there is an input at
d or an input at b or f, or b and f but not if there is an input at a
and b or f; and an output appears at e if there is an input at d and
an input at b or f.
When the output at c is a train of pulses corresponding to the
capacity of the delay line 21, a pulse is to be gated to the output
lead 16 This gating is attained by a pair of AND circuits 24 and 25

and a one digit delay line 26 The output at point c is applied as one
input to the AND circuit 24; the other input, at point g, is from an
OR circuit 28, one input of which is from point b and the other input
of which is from point k The output of the AND circuit, at point h, is
delayed one digit by the delay line 26 and applied, at point k, as one
input of the AND circuit 25, the other input of which is from point b.
The gate circuit 14, referred to in the description of the block
diagram of Fig 1, can be seen in the diagram of Fig 2 to include the
OR circuit 28, AND circuits 24 and 25, and the one digit delay line 26
This circuit is a memory circuit which is triggered during the first
digit interval, by a pulse from point b through OR circuit 28, if
there is an output at c and which circulates a pulse as long as there
is an output at c for each digit interval If this occurs, the pulse is
gated to the output lead 16, during the first digit interval of the
next number, by a pulse from b applied to AND circuit 25 This circuit
thus requires that 70 each digit interval be filled before a pulse can
be gated to the output lead As this only occurs, for the case of n= 4,
when the binary half-adder has counted up to 2 ', i e, 16, an output
pulse is gated only once every sixteen 75 words or once for every
sixteen input pulses which in turn are applied once each word or once
each four digits of the clock frequency.
In the block diagram of Fig 2, to facilitate the explanation of the
logical components of 80 this embodiment of the invention, ideal
circuit elements have been assumed in which no amplification of pulses
is required and all delay incurred in the circuit occurs in the delay
lines, the other circuit elements not introducing any 85 delay In
fact, however, amplification is required and the other elements do
introduce delay so that the delay lines depicted in Fig 2 must be
modified and compensatory delay lines added to take account of this
introduced delay 90 and keep the circuit components in synchronism Fig
4 a is a revised block diagram in which the amplifiers and
compensatory delay lines have been added and the delay of the
previously mentioned delay lines modified to 95 take account of the
delay inherent in the amplifiers The delay introduced by the
amplifiers is, at the clock frequency employed in this embodiment,
substantially one quarter digit, and amplifiers 30 are positioned in
the first 100 stage frequency divider 11, the half-adder circuit 19,
between delay line 21 and the halfadder 19, between delay line 26 and
AND circuit 25 and in the output lead 16 Accordingly, the delay of
lines 22 and 26 is reduced by one 105 quarter digit and of delay line
21 by three quarters digit; the delay loop of delay line 21 includes
two amplifiers 30 and the compensatory delay line 38 referred to
below, so that the total delay of the loop is 4 digits Half 110 digit
compensating delay lines 32 are included in the paths from the first

stage frequency divider 11 to the OR circuit 28 and the AND circuit
25; delay lines 32 delay pulses from circuit 11 the equivalent of the
delay of the 115 pulses to the other input leads of these circuits,
which delay is introduced by the two amplifiers through which these
other pulses pass.
The binary half-adder may advantageously 120 comprise an OR circuit
35, and AND circuit 36, and an inhibitor 37, together with a pair of
amplifiers 30 and a one-quarter digit compensatory delay line 38.
The first stage frequency divider may com 125 prise a delay line
register As seen in Fie 4 a, the circuit comprises an OR circuit 40,
an amplifier 30, a delay line 41, and a compensatory delay line 42
Delay line 41 serves to introduce N digits of delay to pulses from the
-130 OR circuit output back to the OR circuit input In this specific
embodiment the delay line 41 has one and three-quarter digits of
physical delay but is terminated in a short circuit so that pulses of
opposite polarity are reflected back to the input; accordingly, a
positive pulse is applied to the delay line 42 three and onehalf
digits later The total delay between the output and input of the OR
circuit 40 is thus four digits, comprising the one-quarter digit
introduced by the amplifier 30, the three and one-half digits
introduced by the delay line 41 and the one-quarter by the delay line
42.
Advantageously, the negative pulse from the amplifier 30 which is
reflected by the delay line 41, as a positive pulse, is not applied to
delay line 42 due to the interposition therebetween of a diode 43,
seen in Fig 4 b.
The amplifier circuits may advantageously be of the transistor
regenerative type A suitable circuit which is depicted in the
amplifier for the divider 11 in Fig 4 b, includes an output
transformer having its primary winding connected to the collector of
the transistor and at least a pair of secondary windings, one of which
is a feedback winding and the other of which an output winding for
positive output pulses If a negative output pulse is desired, as in
the amplifier 30 of the divider 11 and the amplifier 30 connected to
the inhibitor 37 in the half-adder 19, a third output winding is
provided and wound in the opposite direction to produce a negative
pulse.
The clock frequency is advantageously applied to the emitter of the
transistor, as shown in Fig 4 b In this specific embodiment a four
phase clock is employed, the phases being identified on the drawing as
A, B, C, and D, and being one-quarter digit or 90 degrees of the clock
frequency apart The clock frequency in this embodiment is three
megacycles and the delays of the various delay lines in Fig 4 b are
noted in microseconds in the drawing.

Each of the OR and AND logic circuits advantageously comprises a pair
of diode elements, such as varistors, biassed to enable passage
therethrough of only positive pulses in the forward direction as is
known in the art Each of the delay lines may comprise inductive
members and capacitances, as is also known in the art One particular
type of delay line that may be employed comprises coils wound on an
insulating rod with button condensers connected between a turn of each
coil and ground; such a delay line is shown at page 214 of the book "
Components Handbook ", J F.
Blackburn, Ed (M I T Radiation Laboratory Series, Volume 17, 1949).
In the above discussion it has been assumed that the delay in the
first divider stage is n digits and that the accumulation in the
second divider stage is also N digits; this accumulation in the second
stage is the delay between the sum output of the half-adder circuit
and the input thereto and is indicated by element 13 in Fig 1 It
represents the storage or accumulation capacity of the second stage of
frequency division However, it can be seen that these two periods of
delay need not be the same but may be related to each other by a
constant k, which may be any positive integer The frequency division
attainable for the possible combination is then:Delay of Delay of
Resultant divider 11 line 13 Frequency Division n N 1/(n) ( 2 ") kn N
1/(kn) ( 2 a) If N is a large number it may be difficult and unwieldy
to employ a single short-circuited delay line in the delay line
register of the first 80 stage of frequency division Two such
circuits, as depicted in Fig 5, may be employed together with an AND
gate 45, the upper circuit including a short-circuited delay line 4 ly
having a physical delay of y/2 digits and thus 85 introducing a delay
of y digits into the circuit and the lower circuit including a
short-circuited delay line 41 x having a physical delay of x/2 digits
and thus introduced a delay of x digits into the circuit; the
amplifiers 30 are 9 o here asumed to introduce no delay If x and y are
relative primes, then the resultant frequency division is 1/(x)(y) of
the base frequency However, whether they are relatively prime or not,
the resultant frequency division 95 is equal to the least common
multiple of the individual delays In this manner very large frequency
divisions are attainable in the first stage; in one embodiment six
such circuits having individual fre 100 quency divisions of 1/19;
1/17; 1/15; 1/14; 1/13; and 1/11 were employed and the resultant
frequency division was 1/( 19) ( 17) ( 15) ( 14) ( 13) ( 11) or
1/9,699,690 of the clock frequency This is a frequency 105 division of
the order of 107 to 1; in one specific embodiment wherein the clock
frequency was thre megacycles, an output pulse was provided once every
3 23 seconds It should be noted that the six circuits employed include
110 the numbers containing all the primes less than 20, since 14 and

15 factor as 2 x 7 and 3 x 5.
Fig 6 is a block diagram presentation, again assuming ideal circuit
elements, of another specific illustrative embodiment of this inven
115 tion In the embodiment of this invention depicted in block diagram
form in Fig 2 very large frequency divisions are possible, but not all
desired frequency divisions are attainable.
This is because the frequency division is 1/(n) 120 ( 2 n) the clock
frequency: In the embo iment depicted in Fig 6 all possible frequency
divisions of the word frequency or of the input to the second state
circuit may be attained by presetting a number A into the second stage
125 frequency divider so that the frequency division attainable is
1/(n) ( 2 "-A) the clock frequency.
785,568 785,568 In the embodiment of Fig 6 the initiating pulse from
the single pulse generator 10 is applied to the first stage frequency
divided 11 and also, through an OR circuit 50 to a number or word
generator 51 As will be recalled from Fig 3, the first pulse output
from the frequency divider 11 is delayed by one word interval after
the application of the initial pulse During that first word interval
the word or number placed in the word generator is preset into the
second stage frequency divider.
The word generator may be of any known configuration, but depicted in
the drawing comprising (n-1) one digit delay lines 53 each connected
through a diode 54 and an manually operable switch 55 to a common lead
56 The initial pulse is passed through the delay lines in succession
and appears on the common lead 56 in those digit slots for which the
switches 55 are closed.
This number is then present into the halfadder 19 of the second stage
frequency divider through an OR circuit 186, similar to the OR circuit
18 of the prior embodiment, during the word interval before the
application of the first pulse from the first stage frequency divider
11.
The second stage frequency divider then accumulates pulses in the
delay line 21 as described before, but the accumulation will be
finished A pulses earlier due to the number A having been preset into
the circuit The output pulse appearing on the output lead 16 is fed
back through the OR circuit 50 to the number generator 51 to preset
the number A into the second stage frequency divider at the beginning
of the second cycle of operation and is also applied to an inhibitor
circuit 58 to inhibit the pulse from the first stage frequency divider
11 while the number A is being preset into the second stage circuit A
may be any number from 0 to 2 "-1.
As mentioned above the block diagram of Fig 6 only depicts the logic
elements and assumes them to be perfectly lossless and delayless
Actually each delay line 53 would have associated therewith a

transistor amplifier and, if the clock frequency is three megacycles
be of only 3/4 digit delay to compensate for the one-quarter digit
delay of the transistor amplifier.
For some applications it is desired not to have a single output pulse
from the frequency divider but a train of pulses occurring for onehalf
the cycle of the output frequency of the circuit This is particularly
the case if it is desirede Fto pass the pulses through a low pass
filter to'reconstruct a low frequency sine wave.
Anothe P illustrative embodiment of this invention is depicted in Fig
7 wherein the output is a train of pulses occurring once every digit
for the first half of the cycle of the low frequency output of the
second stage frequency divider.
These pulses provide essentially a square wave which, when passed
through a low pass filter, can give the desired sine wave.
An understanding of the operation of this embodiment can be gained
from a consideration of the time-phase chart of Fig 8 The circuit
depicted in Fig 7 includes the elements of the embodiment of Fig 2 and
a portion of 70 the time chart of Fig 3, applicable to both
embodiments, is repeated in the time chart of Fig 8 It should be
noted, however, that the first line of the time chart of Fig 8 is the
pulse output at point 1 This pulse is applied 75 directly to one input
of a memory cell comnprising an OR circuit 60, a one digit delay line
61, and an inhibiting circuit 62 The pulse immediately appears at the
output point q of the memory 80 cell and circulates in the memory
cell, reappearing at q at each digit time or cycle of the clock
frequency The memory cell thus serves initially as a continuous pulse
source.
To stop this pulse train by turning off the 85 memory cell after
theone-halfcyclehaspassed, an inhibiting pulse is applied to the
inhibitor 62 at precisely the middle of the cycle.
This inhibiting pulse is derived from a gate circuit comprising the
one digit delay line 26, 90 an inhibitor 64, a one digit delay Ine 65,
and an AND circuit 66 The one digit delay line 26 and the inhibitor 64
serve as a selector circuit letting only the last pulse of a train,
appearing at point h, appear at point m, delayed 95 by one digit The
pulse at point m is passed through the one digit delay line 65 and
applied, at point o, to one input of the AND circuit 66 As will be
recalled, a pulse train appears at point h only if a pulse occurs at c
100 in synchronism with a pulse at b Thus only those pulse trains
corresponding to numbers having a pulse in the first digit interval
enter this gating circuit Additionally the other input of the AND
circuit 66 is also the pulse 105 from point b Therefore the output of
the AND circuit 66, at point p, is a pulse at the start of a word or
number interval when the prior number, at point c, had a pulse at the

first digit space and sufficient digits so that the 110 last digit,
delayed by two digit intervals, occurs at the first digit interval of
the next number.
The time chart of Fig 8 shows that this occurs only after the number "
7 " has been counted by the half-adder 19, so that a pulse only 115
appears at p at the start of the eighth number interval This however,
is precisely the halfcycle point of the output of the frequency
divider in this embodiment The pulse at p is applied to the inhibiting
lead of the inhibi 120 tor 62 to turn off the memory cell and stop the
train of digit pulses appearing at point q.
In the above-described embodiments it has been assumed that the first
stage of frequency division is triggered on application thereto of 125
a single initiating stage of frequency division to which is applied,
from a clock frequency source 70, a train of clock pulses These pulses
are applied to an inhibitor circuit 71 on one input lead 72 thereof;
the first pulse applied 130 785,568 appears also on the output lead 73
and is applied to the second stage of frequency division as described
above.
The output pulse, however, is also applied to the inputs of N parallel
delay lines 75 having delays of from 1 digit time of the clock
frequency to (n-1) digit times, inclusive The outputs of the delay
lines 75 are all applied to the other input lead 76 of the inhibitor
circuit 71 and prevent the appearance on the output lead 73 of a pulse
for the next (n-1) digit times in accordance with the known manner of
operation of inhibitor circuits Accordingly a pulse appears at the
output lead 73 of the first stage of frequency division only once
every N cycles of the clock frequency, and the circuit accordingly
attains a frequency division of n/i.
The delay lines 75 connected in parallel are, in effect, a pulse train
generator Other types of pulse train generators may be connected
between the output lead 73 of the inhibitor circuit 71 and the input
lead 76 thereof.
In Fig 9 idealized circuit elements havagain been assumed It is to be
understood, however, that amplifiers, having certain inherent delays,
would be utilized If these amplifiers are clocked, as disclosed in the
prior figures, at the clock frequency of the circuit, then the
initiating signal applied from source at each cycle of the clock
frequency need not comprise a train of pulses but may actually be a
direct current voltage.
* Sitemap
* Accessibility
* Legal notice
* Terms of use

* Last updated: 08.04.2015
* Worldwide Database
* 5.8.23.4; 93p
* GB785569 (A)
Description: GB785569 (A) ? 1957-10-30
Improvements in rotary feeders for positive pressure pneumatic conveyor
systems
COMPLETE SPECIFICATION.
Improvements in Rotary Feeders for Positive Pressure Pneumatic
Conveyor Systems.
We, HENRY SIMON LIMITED, a British
Company, of Bird Hall Lane, Cheadle
Heath, Stockport, Cheshire, 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 rotary feeders as used in positive pressure
pneumatic conveying equipment for the transference of pulverulent
material from hoppers, separators or processing machines to ducts
along which the material is to be conveyed pneumatically and is
particularly directed to the sealing means whereby pressure loss at
rotor shaft seal housings is prevented.
In rotary feeders, rotor shaft housing pressure retaining seals of
various types suitable for internal pressure retention during the
feeding of most types of pulverulent materials are well known but
there is a group of such materials, for instance sugar or portland
cement, which when in contact with the sliding surfaces of relatively
moving elements cause considerable increase in the friction generated
at such surfaces, giving rise in the case of rotary feeders, where
operational pressure tends to force the material into the sealing
means, to rapid deterioration, seizure and destruction of said known
types of pressure retaining seals and consequent pressure loss and
material leakage from the system.

The object of the present invention is to provide in positive pressure
pneumatic conveying equipment for the conveyance of sugar, portland
cement and like materials, rotary feeders having at each rotor shaft
seal housing an improved form of sealing means which will avoid the
above disadvantages.
The invention consists in a rotary feeder pneumatic pressure conveying
equipment in which the ends of the rotor shaft pass through sealing
means in the end walls of the rotor casing, each end wall having
therein beyond the - aperture through which the shaft passes a recess
or cavity into which material which may pass through said aperture can
accumulate, the wall of the recess or cavity opposite to the apertured
wall comprising a resilient washer having a part thereof which
surrounds and extends axially along the shaft into the recess or
cavity, so that such material will press upon said part and ensure its
intimate sealing contact with the shaft. There may be beyond each
resilient washer, a sealing washer to prevent the ingress from
exterior sources of oil, water or other liquid or solid material which
could adversely affect the sealing function of the resilient washer,
the said sealing washer being protected from the material in the
cavity by the action of the resilient washer.
The invention further consists in a rotary feeder as aforesaid in
which the resilient washer which forms a wall, of each recess or
cavity around the shaft comprises a part of cylindrical shape which
extends coaxially along and in sealing contact with the shaft and a
part of radial disc like form which is clamped to the end wall by an
assembly comprising a gland plate, a metal ring, a sealing washer
which makes intimate contact with the shaft, and a further metal ring,
the assembly being secured in place by bolts and nuts.
Referring to the accompanying explanatory drawings:-
Figure 1 is a longitudinal sectional elevation on the line A B of
Figure 2 and Figure
2 a cross-sectional view on the line C D of
Figure I showing a rotary feeder with retaining seals for the rotor
shaft constructed in one convenient form in accordance with this
invention
Figure 3 is a detail sectional view drawn to a larger scale than
Figure 1 showing one of the retaining seals for the rotor Shaft.
The rotor comprises a shaft a having strips b secured in longitudinal
slots in the shaft and flexible blades c secured to the strips b. The
rotor revolves in a casing d which has an inlet branch at e for the
material to be delivered by the rotor. There are pockets f between the
blades c and such pockets carry the material from the inlet branch at
e to the lower portion of the casing d, when the pockets in succession
come into alignment with inlet and outlet branches g and h

respectively, the branch g introducing compressed air to the pockets
in succession which blows the contents of the pockets into the branch
h which is connected to the conveying system.
The aperture dl in the casirig is for releasing the air pressure in
each pocket before it arrives at the filling position beneath the feed
branch e.
The rotor shaft ends i pass through coaxial holes j in the walls of
the casing, these holes leaving a generous clearance around the shaft
The walls are relatively thin and tapered at the said holes Z and the
holes lead to coaxial recesses or cavities k in the walls around the
shaft. The wall of each recess or cavity k opposite to that containing
the hole j is provided by a resilient washer m made of leather or like
material having a tubular part which extends coaxially around the
shaft and a part which extends radially around the shaft. The tubular
part makes intimate contact with the shaft and the complete washer is
held in place by an assembly, comprising a gland plate n, a metal ring
a a resilient compressed washer p which may be made of felt and which
makes intimate contact with the surface of the shaft end t, and a
further metal ring q. The assembly is secured in place by bolts and
nuts in the usual manner.
In operation, a small quantity of the material passes from the pockets
between the blades c through the holes j around the shaft ends i into
the recesses or cavities k, which results in the production in each
recess or cavity of a ring of the material which presses upon the part
of the washer m which surrounds and makes intimate contact with the
shaft and ensures that such part of the washer makes sealing contact
with the shaft and effectively prevents infiltration of such material
into the felt or like washer p and the cylindrical surface of such
washer p around the shaft.
The material in each cavity k in addition to holding the part of the
washer nt which is coaxially around the shaft in intimate contact with
the latter also provides for the washer m a protective barrier due to
the fact that the material in contact with the stationary walls of the
cavity adheres firmly thereto and the material in contact with the
rotating shaft i adheres to the surface thereof and rotates with it,
inducing within the rest of the material in the cavity a confused
particle motion and providing a resistance to the ingress of
additional material to the cavity, thus protecting the washer nt from
the effects of undue pressure. Such material remains confined in the
recess or cavity and does not change.
What we claim is : -
1. A rotary feeder for pneumatic pressure conveying equipment in which
the ends of the rotor shaft pass through sealing means in the end
walls of the rotor casing, each end wall having therein beyond the

aperture through which the shaft passes, a recess or cavity into which
material which may pass through said aperture can accumulate, the wall
of the recess or cavity opposite to the apertured wall comprising a
resilient washer having a part thereof which surrounds and extends
axially along the shaft into the recess or cavity, so that such
material will press upon said part and ensures its intimate sealing
contact with the shaft.
2. In a rotary feeder as claimed in Claim 1, the provision beyond each
resilient washer of a sealing washer which makes intimate contact with
the shaft and is protected from the material by the action of said
resilient washer.
3. A rotary feeder as claimed in Claim 1 or 2, in which the resilient
washer which forms a wall of each recess or cavity around the shaft
comprises a part of cylindrical shape which extends coaxially along
and in sealing contact with the shaft and a part of radial disc like
form which is clamped to the end wall by an assembly, comprising a
gland plate, a metal ring, a sealing washer which makes intimate
contact with the shaft and a further metal ring, the assembly being
secured in place by bolts and nuts.
4. The improved rotary feeder for pneumatic pressure conveying
equipment substantially as described and as illustrated.
* GB785570 (A)
Description: GB785570 (A) ? 1957-10-30
Functional fluids

785,570 i) Date of Application and filing Complete Specification Sept
22, 1955.
No 27068/55.
Application made in United States of America on Sept 23, 1954.
Index at Acceptance: -Class 69 ( 2), P 12.
International Classification: -FO 3 c.
Functional Fluids We, MONSANTO CHEMICAL COMPANY, a corporation
organised under the laws of the State of Delaware, United States of
America, of 1700, South Second Street, City of St.
Louis, State of Missouri, 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 functional fluid compositions and more
specifically to hydraulic mineral oil compositions having particularly
useful viscosity-temperature relationships These compositions are
especially suited for use in aircraft hydraulic systems, and similar
uses where hydraulic fluids are required to have outstanding low
temperature viscosity properties.
According to the present invention there is provided a functional
fluid comprising (a) a mineral base oil having a pour point not higher
than -70 F, a flash point not lower than 1800 F, and a viscosity not
greater than 12 centipoises at 1000 F and (b) a copolymer of (i) at
least one alkyl acrylate having 8 to 10 carbon atoms in the alkyl
group and (ii) methyl and/or ethyl acrylate, the copolymer having an
average of from 5 5 to 7 carbon atoms in the alkyl groups and a
molecular weight such that the specific viscosity at 770 F of a 2 % by
weight solution thereof in toluene is from 0 4 to 1 2, the copolymer
being present in an amount sufficient to give a composition having a
viscosity of at least 8 centipoises at 1300 F but not greater than 700
centipoises at -40 F.
The mineral base oil utilized in the functional fluids of this
invention are light mineral oils well known to be useful as functional
fluid, and particularly hydraulic oil, bases However, in order to
respond effectively to the viscosity index improving additives used in
accordance with the present invention the base oil used must be one
having a pour point not higher than -70 F, and preferably lower than
-75 F, a flash point not lower than 1800 F, and preferably higher than
2000 F, lPrice 3 s 6 J l and a viscosity not greater than 12
centipoises, and preferably less than 10 centipoises, at 50 1000 F.
The alkyl acrylate interpolymers must meet three requirements in order

to be satisfactory viscosity index improvers for use in the
compositions of this invention: ( 1) they must be 55 derived from at
least two different acrylate monomers, each of which is selected with
respect to the number of carbon atoms in the alkyl group; ( 2) the
relative proportions of the acrylate monomers used in producing the 60
copolymers employed must be such that the average number of carbon
atoms in the alkyl groups in the resulting copolymer falls within
narrow limits; and ( 3) the molecular weight must be relatively low
and within a specified 65 range.
( 1) ACRYLATE MONOMERS The alkyl acrylate copolymers used in
accordance with the prpesent invention must be derived from at least
one monomeric alkyl 70 acrylate which contains 8, 9 or 10 carbon atoms
in the alkyl group and from methyl and/or ethyl acrylate The monomers
containing 8, 9 or 10 carbon atoms in the alkyl group may be either
n-alikyl acrylates or 75 branched-chain alkyl acrylates or a mixture
thereof Examples of suitable acrylates are n-oetyl acrylate, n-nonyi
acrylate, n-decyl acrylate, 2-ethylhexyl acrylate,
1,1,3,3-tetramethylbutyl acrylate, 1,3,5-trimethylhexyl 80 acrylate,
2,2,4,4-tetramethylpentyl acrylate and 2,4,6-trimethylheptyl acrylate.
( 2) MONOMER PROPORTIONS The relative proportions of the monomers to
be copolymerised should be such that the average number of carbon
atoms in the alkyl grouhs in the copolymer will be between 5 5 and 7
0, and preferably between 60 and 6 8.
It is contemplated that a mixture of monomers within each group may be
used instead of a single individual In such a case, the mixture is
considered as a single monomer having a number of carbon atoms in the
alkyl group equal to the molar average of the various components of
the mixture Thus, if a mixture of acrylic esters made from a mixture
of C 8 and C 1, alcohols is to be used, and the mixture contains the C
8 and CID esters in a mol ratio of 2: 1, the mixture would be
considered as an acrylic monomer containing 8 67 carbon atoms in the
alkyl groups.
Examples of suitable acrylic monomer mixtures for polymerization to
form copolymers for use in the compositions of this invention are as
follows: 85 % by weight of 2-ethylhexyl acrylate and 15 % by weight of
ethyl acrylate; % by -weight of ii-cctyl acrylate and 10 ' by weight
of methyl acrylate; 80 % by weight of 2-ethylhexyl acrylate and 20 %
by weight of ethyl acrylate; 80 % by weight of an acrylic ester of an
" oxo " alcohol derived from an isobutylene dimer and 20 % by weight
of ethyl acrylate; 85 % by -w eig'ht of itr-decyl acrylate and 15 % by
weight of methyl acrylate; 40 % by weight of r-octyl acrylaue, 40 % by
weight of wz-decyl acrylae and 20 % by weight of ethyl acrylate.
( 3) MOLECULAR WEIGHT It is extremely difficult to determine the true
molecular weight of a polymer, however, the viscosity of a standard

quantity of any polymer in a solvent is a function of the molecular
weight of the polymer Consequently, for the purposes of the present
invention, the molecular weights of the copolymers used herein will be
specified in terms of the specific viscosity at 770 F of toluene
solutions containing 2 % by weight of the polymer The molecular
weights of the alkyl acrylate copolymers utilized in the compositions
of the present invention should be such that the specific viscosity of
the aforementioned solutions is from 0 4 to 1 2 and preferably between
0 6 and O 95.
The copolymers of the aforesaid alkyl acrylates are usually utilized
in the compositions of the invention in concentrations between 3 and
%, by weight, and preferably between 5 and % by weight, the exact
concentration depending to some extent upon the particular base oil
with which the copolymers are to be incorporated -The concentration of
the copolymer should be sufficient to give the resulting functional
fluid a viscosity of at -least 8 centipoises, and preferably at least
10 centipoises, at 1300 F; however, the concentration should be no
higher than that required to give the functional fluid composition a
viscosity of 700 centipoises, and preferably 600 centipoises, at -40
F.
The following examples illustrate the nature of the present invention
and the manner in which it may be carried into effect.
EXAMPLE 1
A mixture of 85 grams of 2-ethylhexyl acrylate, 15 3 grams of ethyl
acrylate and 1 grams of a refined mineral hydraulic oil base having a
viscosity of 3 68 centipoises at 1003 F and 1 35 centipoises at 210 '
F, a pour point below -75 F and a flash point above 2000 F was placed
in a glass flask equipped with a stirrer Air was removed from the
flask by flushing out with nitrogen and polymerization was nitiated by
the addition o 005 grams of benzoyl peroxide After 2.5 hours, a
further 0 2 grams of benzoyl peroxide was added The reaction was
allowed to proceed for an additional 3 5 hours when a yield of 982 %
of copolymer was obtained.
The reaction temperature was maintained at 1940 F throughout the
reaction by controlled water cooling The molecular weight of the
resulting polymer was such that a 2 % by weight solution thereof in
toluene had a spccific viscosity of 0 92.
18.7 grams of the foregoing reaction product (including the mineral
oil solvent) was mixed with an additional 81 3 grams of the same
mineral oil to give a functional fluid composition containing 7 5 % by
weight of poiymer in the oil The composition had a viscosity or 99
centipoises at 130 W F and 525 centipoises at -40 F The viscosity
index thereof was 229 as compared with an index o O 98.8 for the base
oil witnout the acrylate -copolymer viscosity index improver.

EXAMPLE 2
A mixture ot 157 7 grams of 2-ethylhexyl acrylate, 18 2 grams of ethyl
acrylate and 263 grams of a mineral oil having the same pro 95 perties
as that used in Example 1 was prepared, and 183 1 grams of the mixture
was placed in a glass reaction flask equipped with a stirrer Air was
removed from the flask with a current of nitrogen and the
polymerization 100 initiated by the addition of 0 037 grams of benzoyl
peroxide, an additional 0 051 grams of benzoyl peroxide was dissolved
in 1 ml of benzene and mixed with the remainder of the monomer-oil
mixture After 30 minutes, 105 gradual addition of the remaining
monomeroil-catalyst mixture was begun at the rate of 2.6 mil per
minute and continued until all of the mixture had been added to the
reaction flask After 5 hours an additional O 044 grams 110 of benzoyl
peroxide was added to the reaction mass After an additional 1 75
hours, the polymerization had been completed and a substantially 100 %
yield of acrylate copolymer obtained The reaction temperature had been
115 maintained at 1760 F throughout the entire reaction by controlled
water cooling The molecular weight of the resulting acrylate copolymer
was such that a 2 %Do by weight solution thereof in toluene had a
specific viscosity 120 of 0 91.
7.5 grams of the foregoing reaction product (including the mineral oil
solvent) was mixed with an additional 42 5 grams of the same mineral
oil to give a functional fluid composi 125 tion containing 6 %o by
weight of polymer in the base oil The composition had a viscosity
785,570 785,570 of 8 25 centipoises at 1300 F and 360 centipoises at
-40 F The viscosity index thereof was 245 2 as compared with an index
of 98 8 for the bae oil without the acrylate copolymer viscosity index
improver.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB785571 (A)
Description: GB785571 (A) ? 1957-10-30

Improvements in or relating to pit props
Date of Application and filing Complete Specification: Oct 4, 1955.
&g I No 28209155.
Application made in Germany on Oct 18, 1954.
Complete Specification Published: Oct 30, 1957.
Index at acceptance:-Class 20 ( 2), E 2 D 3 C.
International Classification -E 2 lld.
Improvements in or relating to Pit Props We, 'GUTEHOFFNUNGSHUTTE
STERIKRADE ARTIENGESELLSCHAFT, of Lipperfeld 1, Oberhausen, Rhld,
Germany, a German Company, 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 a pit prop of the type comprising an outer
prop member, an inner prop member of trough section slidably received
in said outer prop member, and a clamp comprising a clamp frame
affixed to the outer prop member, a clamping cam member extending into
said trough section and being carried by said clamp frame for pivotal
movement in the longitudinal direction' of the prop, and a jaw for
transmitting clamping force from said clamping cam member to said
inner prop member, the clamping cam member being adapted to be carried
along by a downward movement of said inner prop member relative to
said outer prop member in such a manner that the clamping force of
said clamping cam member is increased, In yieldable pit props it has
proved suitable to construct the clamp so that the clamping force
exercised by the clamp does not remain constant during the lowering of
the upper prop member but increases to Ma predetermined limiting value
This can be achieved by means of a clamping cam member which is
carried in the clamp for pivotal movement in the longitudinal
directioni of the prop and which is carried along by the subsiding
inner prop member to increase the clamping force, which is transmitted
by a clamping jaw.
To limit the increase 'of the clamping force a stop is provided which
will retain said clamping cam member when the predetermined limiting
value has been reached.
In props having a laterally 'open, hollow section member, e g a trough
section, which is superior to an entirely closed section because it

has a larger number of friction faces available, the clamping cam
member extends M Price 3 s 6 d J laterally into the prop member
Previously a special bracket or support was provided in the lower prop
member as a stop for the 50 clampiing cam member.
It is an object of the invention to improve these prior props so that
the clamping cam member will be supported at the end of its downward
movement even without a special 55 stop, bracket or the like in the
lower prop member so that the clamping force of the clamp cannot
increase beyond the predetermined limiting value as the upper prop
member subsides 60 This object is achieved according to the invention
thereby that the clamping cam member consists of a two-aimed lever,
which is supported on a bottom portion of the clamp frame Ai line with
the wall of the outer prop 65 mflember and which has an outer lever
arm extending into the clamp and adapted to engage the clamp frame.
In its abutting position the clamping cam member is supported on the
clamp frame 70 above and below As a result a clamping wedge, pivotally
supporting the clamping cam, is relieved of forces acting in the
longitudinal direction of the prop The ratio of the two lever arms of
the clamping cam member may 75 be selected so that the abutment forces
to be absorbed by the outer lever arm are as small as possible.
The accompanying drawings show some illustrative embodiments and
explain further 80 details of the invention.
Fig 1 is a longitudinal sectional view of a prop according to the
invention.
Fig 2 is a transverse sectional view taken on line I Il-I of Fig 1 85
Fig 3 shows the clamping cam member in its initial position, Fig 4 is
a modified form of the clamping cam member, and Fig 5 is a transverse
cross section of an 90 other construction thereof.
According to Figs 1-3 the inner prop member 1 'and the outer prop
member 2 are channel sections open on the side facing the 5,571
2,785,571 clamp The clamp frame 3 surrounds the outer prop member 2
and is affixed to the same, e.g 'by welding A clamping wedge 4 is
inserted in the clamp frame and bears on the outside on an abutment 5
whereas it engages a clamping cam member 6 on the inside The clamping
wedge 4 is cylindrically rounded on both longitudinal sides the
abutment 5 and the engaging surface of the clamping cam member 6 in
engagement with the wedge 4 being shaped accordingly, so that the
clamping wedge 4 and clamping cam member 6 can be inclined and adjust
themselves relative to each other.
The clamping cam member represents a two-armed lever, whose inner
lever arm has a rounded head 6 a engaging the bearing socket of a
clamping jaw 7 The latter is fitted between the flanges of the inner
prop member 1 and clamps the latter against the outer prop member 2
The outer lever arm 6 b of the clamping cam member extends into the

clamp frame 3 The clamping cam member has a base portion 6 c, which is
supported on the bottom of the lock frame 3 in line with the outer
prop wall 2 so that the supporting force of the clamping cam member is
effective as far as possible only as a compressive force in the wall
of the outer prop member 2, not as a bending moment in the lock frame
3.
Before the inner prop member 1 begins to subside under the rock load
to be carried, the clamping cam member 6 has approximately the
position shown in Fig 3 In that position the outer lever arm 16 b of
the clamping cam member is spaced from the upper wall of the clamping
frame 3 As the inner prop member subsides it carries the clamping or
friction jaw 7 along to swing the clamping cam member in the
anticlockwise sense.
During that shifting of the clam-ping cam member the clamping or
friction jaw 7 is pressed with increasing force against the inner prop
member 1 Finally the clamping cam member reaches the position shown in
Fig 1 during the subsiding of the inner prop member In that position
the outer lever arm 6 b of the clamping cam member bears on the clamp
frame 3 to prevent a further downward swing of its inner lever arm and
a further downward movement of the clamping or friction jaw 7.
In this end position the clamping cam member 6 bears on the clamp
frame with its inner lever arm 6 b as well as with its base part 6 c,
against the load acting vertically downwards on the head 6 a of its
inner lever arm.
It is important in practice that this final position of the clamping
cam member 6 shown in Fig -1 is determined as exactly as possible in
dependence on the maximum value admissible for the clamping force of
the clamp in each case.
To adjust this limiting value the final position of the clamping cam
member may be varied if desired, by shims disposed under the base part
6 c and/or over the outer lever arm 6 b.
A spring 8, which is inserted in a recess 9 of the clamping jaw 7 and
bears on the one 70 hand on the clamping jaws 7 and, on the other hand
on a disc 10 is provided to lift the clamping jaw 7 and to return the
clamping cam member into its initial position automatically after the
wdge 4 has been loosened The disc 75 is affixed, if desired in an
adjustable manner, by means of a bolt 11 to a supporting arm 12, which
limits the upward stroke of the clamping jaw 7 so as to fix its upper
end position The stroke of the jaw 7 could 80 -be varied by adjusting
the bolt 12 The return spring 8 may be omitted, if desired, Hand a
returning force may be exercised by giving the clamping cam member an
overweight on the lever arm opposite to the clamping wedge 85
According to -Fig 4 a sliding jaw 6 c may Abe provided as a support
for the base part of the clamping cam member 6 That sliding jaw can

slide on the bottom of the clamp frame 3 during the movements of the
clamp 90 ing cam member The upper side of the sliding jaw is formed as
a bearing socket so that the clamping cam member can adjust itself on
the sliding jaw with the least constraint.
A second sliding jaw 6 b corresponding to the 95 base sliding jaw, may
be provided as an abutment for the outer lever arm of the clamping cam
member The upper sliding jaw may be arranged to provide an overweight
for the clamping cam member in such a manner that 100 the clamping cam
member wvill; re-erect itself automatically when the clamping wedge 4
is loosened Since the base part 6 c is more heavily loaded than the
engaging end of the lever arm 6 b the upper sliding jaw is less
essential 105 than the lower one.
The constructions illustrated and described are only exemplary
embodiments of the invention, which is not restricted to these
specific constructions Numerous modifications are pos 110 sible within
the scope of the invention For instance, the outer prop member 2 could
be a closed tube section It is only essential for the invention that
the inner prop member is an open hollow section A trough section in
115 the sense of the invention, is any section open on one side, e g a
channel section, I-section or V-section.
An I-section may be considered as composed of two channels For this
reason the 120 Invention can also be applied to it, as is showan in
Fig 5 The clamping cam member 6 engages on one side the section web,
which bears on the other side against an abutment 13 incorporated in
the clamp frame 3 Such a 125 special abutment would not be necessary,
e g, for a channel section.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p
* GB785572 (A)
Description: GB785572 (A) ? 1957-10-30
A method and apparatus for continuously applying a protective coating to

metal coated strip
A high quality text as facsimile in your desired language may be available
amongst the following family members:
BE542953 (A) FR1147439 (A)
BE542953 (A) FR1147439 (A) less
785,572 Date of Application and filing Complete Specification Oct 18,
1955.
No 29673/55.
Application made in United States of America on March 23, 1955.
Index at Acceptance:-Classes 2 ( 5), R 1 C( 6: 7: 8: 12: 16); 2 ( 6),
P 1 A, P 1 C( 5: 6 B: 8 B: 8 C: 13 A:
14 A: 14 B: 20 B: 20 C), PID(IB: 5); 39 ( 3), H( 2 D 1 B: 3 C); and
140, K 3 D.
International Classification: -B 05 CO 8 f, g H 05 b.
A method and Apparatus for Continuously Applying a Protective Coating
to Metal Coated Strip We, WHEELING STEEL CORPORATION, a Corporation
organised under the laws of the State of Delaware, United States of
America, of Wheeling, West Virginia, 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 continuously applying a protective coating
to metal-coated strip It relates to an improvement in the continuous
application of a protective coating to metal-coated strip whereby the
efficiency of the operation is greatly improved and a superior and
more uniform product is produced.
While our invention is applicable to the continuous application of a

protective coating to metal strip coated with various metals such as
spelter (galvanized), terne, tin, aluminium, etc, our invention has
perhaps found its most common use in the continuous application of a
protective coating to galvanized steel strip, and for purposes of
explanation and illustration the invention will be described in
connection with the continuous application of a protective coating to
galvanized steel strip.
It is known to those skilled in the art that galvanized steel is
subject to a non-uniform discoloration sometimes called " wet storage
stain " which occurs when galvanized steel is stored in wet or damp
condition or in humid atmosphere To obviate wet storage stain it has
heretofore been proposed to apply to galvanised steel a protective
coating which is applied in liquid form and subsequently dried.
Th, protective coating may be a plastic or non-plastic material or a
mixture thereof which is applied in a very thin coating or film It may
be dried simply by evaporation of solvent or by polymerization, or
both if the protective coating material contains both polymerizable
and non-polymerizable materials Examples of materials which may be
used for the formation of a protective coating on metal-coated strip
are: THERMOPLASTIC.
Per cent.
Formula No 1 by weight Polyvinyl butyral 4 65 Polymerized rosin 4 65
Isobutyl alcohol 4 78 Acetone 5 69 Isopropanol ( 99 %) 79 44 Water 32
Phosphoric acid ( 85 %); 32 Chromium trioxide 15 00 Formula No 2
Polyvinyl butyral 8 84 Isobutyl alcohol 3 99 Acetone 9 82 Ethyl
alcohol 75 86 Water 61 Phosphoric acid ( 85 %) 61 Chromium trioxide 27
00 Formula No 3 Polymerized rosin 5 00 Ethyl alcohol 82 93 Polyvinyl
butyral 4 42 Isobutyl alcohol 2 00 Acetone 4 90 Water 30 Phosphoric
acid ( 85 %) 30 Chromium trioxide 15 00 THERMOPLASTIC AND
THERMOSETTING (PREDOMINANTLY THERMOSETTING).
Formula No 4 Polyvinyl butyral 3 75 Phenolic resin 2125 Isopropanol (
99 %) 7125 Isobutyl alcohol 3 75 00 THERMOPLASTIC AND THERMOSETTING
(PREDOMINANTLY THERMOPLASTIC).
Formula No 5 Phenolic resin 2 5 Isopropanol ( 99 %) 5 6 Butyl alcohol
4 Isobutyl alcohol 4 O Toluol 1 4 Polyvinyl butyral 8 O Acetone 8 8
Ethyl alcohol 68 1 Water 5 Phosphoric acid ( 85 %,o) 5 Chromium
trioxide 2 100 0 THERMOSETTING.
Formula No 6 Phenolic resin 25 O Isopropanol ( 99 %) 56 25 Butyl
alcohol 3 75 Toluol 15 00 10000 Difficulty has heretofore been
experienced in the continuous application of a protective coating to
metal-coated strip due to the necessity of rendering the protective
coating material substantially dry before it is contacted by any
portion of the apparatus following the protective coating material
applying means If the protective coating material is contacted by any

portion of the apparatus while it is wet the uniformity of the
protective coating is interfered with and inferior product is produced
It is desirable to effect the application of the protective coating
material in a high speed continuous operation and in order to dry the
protective coating material before it is contacted by any portion of
the apparatus following the protective coating material applying means
it is necessary either to pass the strip through a great distance
while it is being dried and before it is contacted by any portion of
the apparatus following the protective coating material applying
means, which is highly undesirable, or to apply a great amount of
heat.
But a continuous protective coating applying line, like any other
continuous line, is subject to slowdowns and stoppages, and when
slowdowns and stoppages occur there is danger that the heat applied to
dry the protective coating material may burn the protective coating
material or indeed even melt the metal coating on the strip.
We have devised a method and apparatus overcoming the disadvantages of
prior methods and apparatus for continuously applying a protective
coating to metal-coated strip We have found that superior results are
obtained by drying the protective coating material by electric
induction heating Not only is electric induction heating highly
efficient but it is subject to instant and close control which adapts
it particularly for use in a continuous line for applying a protective
coating to metalcoated strip The magnitude of electric induc 65 tion
heating can be altered instantly so that when the strip slows down or
stops the heat applied to the strip may be simultaneously
proportionately reduced or shut off entirely That may be accomplished
by a suitable rheostat in 70 the electric induction heating circuit
The rheostat may be manually or automatically operated The operation
of the rheostat may be controlled in relation either to the
temperature of the protective coating material being dried 75 or to
the speed of advance of the strip since the speed and temperature bear
direct relation to each other We find it desirable to couple the
rheostat to a variable speed line drive motor for advancing the strip
so that the magnitude 80 of the electric induction heating is
maintained proportional to the speed of the motor and hence to the
speed of advance of the strip.
Alternatively the rheostat may be operated from a thermocouple or
other heat sensitive 85 device reflecting the temperature of the
protective coating material being dried Thus we maintain at all times
the proper magnitude of drying heat so that when the strip slows down
or stops the protective coating is not burned 90 and the metal coating
on the strip is not melted It is not possible to maintain such a
control using any other method of applying heat to dry the protective

coating material.
We produce a superior and unprecedentedly 95 uniform product in a
highly efficient and economical manner.
We provide a method of continuously applying a protective coating to
metal-coated strip comprising advancing thb strip, during such 100
advance applying to the strip a protective coating material which is
in liquid form as applied and thereafter and while the strip continues
to advance heat treating the protective coating material by electric
induction heating and 105 thereby rendering the protective coating
material substantially dry before it is contacted by any portion of
the apparatus following the protective coating material applying
means.
We control the magnitude of the electric induc 110 tion heating in
accordance with the speed of advance of the strip to insure rendering
the protective coating material substantially dry before it is
contacted by any portion of the apparatus following the protective
coating 115 material applying means without deleterious overheating.
We prefer to continuously treat strip by continuously advancing the
strip through a metal coating station and a; that station applying 120
metal coating material to the strip, as the strip continues its
advance applying to the metalcoated strip a protective coating
material which is in liquid form as applied, thereafter and while the
strip continues to advance heat treat 125 ing the protective coating
material by electric induction heating and thereby rendering the -2
785,572 785,572 protective coating material substantially dry before
it is contacted by any portion of the apparatus following the
protective coating material applying means and controlling the
magnitude of the electric induction heating in accordance with the
speed of advance of the strip to insure rendering the protective
coating material substantially dry before it is contacted by any
portion of the apparatus following the protective coating material
applying means without deleterious overheating, although we may apply
the protective coating material to strip which has previously been
galvanized or coated with other metal and coiled Continuous lines for
applying metal coatings to strip, notably steel strip galvanizing
lines, have recently attained unprecedentedly high speeds The only
practicable way of applying to strip in a single continuous line a
metal coating and a protective coating over the metal coating without
intermediate coiling of the strip is by the use of electric induction
heating for drying the protective coating material It is preferable
that the control of the magnitude of the electric induction heating be
effected automatically as explained above but it is possible to effect
the control manually if desired.
The protective coating material is preferably applied by rollers The

applying rollers may receive liquid coating material from other
rollers partly immersed in liquid coating material similarly to the
application of ink to the form in a printing press We have found that
the protective coating material can be applied more evenly and its
thickness more closely controlled when applying rollers are used than
when the protective coating material is otherwise applied The
protective coating material is applied in an extremely thin coating or
film and the requisite uniformity of such a thin coating, particularly
in a high speed line, can be most effectively maintained through
application of the protective coating material to the strip by
rollers.
Other details, objects and advantages of the invention will become
apparent as the following description of a present preferred
embodiment thereof and a present preferred method of practicing the
same proceeds.
In the accompanying drawing we have shown a present preferred
embodiment of the invention and have illustrated a present preferred
method of practicing the same in which the single figure is a diagram
illustrating one form of apparatus for carrying out our invention and
one method of practicing the invention which may be employed.
The strip being pcoated is designated by reference numeral 2 The
drawing illustrates a continuous metal-coating and protective coating
line which will be deemed to be a continuous steel strip galvanizing
and protective coating line All of the elements of the apparatus are
shown purely diagrammatically as their detailed construction will be
understood by those skilled in the art.
The strip passes downwardly about a roll 3 immersed in molten spelter
4 in a galvanizing pot 5 The strip moves horizontally in the gal 70
vanizing pot and then about a roll 6 and up out of the molten spelter
4 between exit rolls 7 The galvanized strip in its upward movement
passes through a cooling duct 8 It thereafter passes about a roll 9
and thence hori 75 zontally through another cooling duct 10 to another
roll 11 The galvanized strip at the proper temperature for application
of the liquid protective coating material passes downwardly from the
roll 11 between protective go coating material applying rollers 12
which receive liquid protective coating material from rollers 13
partly immersed in baths 14 of liquid protective coating material at
opposite sides of the strip It should be explained that although 85
the liquid protective coating material is shown as being applied to
the strip as the strip moves vertically downwardly such material may
be applied to the strip while the strip is moving upwardly or
horizontally or in any other direc 90 tion We prefer to apply the
liquid protective coating material to the strip while the strip moves
downwardly because application in that manner facilitates control of

the thickness of the coatings applied to the opposite sides of 95 the
strip When the strip is moving horizontally the control of the
thickness of the coatings applied to the top and bottom surfaces
thereof so that such coatings will be of equal thickness is much more
difficult 100 The coating material applying rollers 12 are preferably
driven at a peripheral speed which is at all times equal to the speed
of advance of the strip This results in the proper thickness of
protective coating material being 105 applied to each face of the
strip at all times during the operation even though the strip may slow
down or stop from time to time.
From the liquid coating material applying means the strip moves
straight downwardly 110 as shown and is dried before the protective
coating material is contacted by any portion of the apparatus
following the rollers 12 The strip with the liquid protective coating
material thereon passes through an electric induction 115 heating coil
15 which applies to the strip through induction as known to those
skilled in the art heat which in our process is effective for drying
the protective coating material and for polymerizing any portion of
the protective 120 coating material which may be polymerizable.
From the electric induction heating coil 15 the strip passes
downwardly and is sprayed by water sprays 16 and passes about a roll
17 partly immersed in a bath of water 18 in a 125 water tank 19 The
strip thence passes between squeegee rolls 20 and through a drier 21
and about driving rolls 22 which supply the motive power for advancing
the strip through (the apparatus The strip thence passes to a shear
130 785,572 to be sheared into sheets or to a reel for coiling The
rolls 22 are driven by the previously mentioned variable speed line
drive motor (not shown).
The speed of the variable speed line drive motor which drives the
rolls 22 is at all times proportional to the speed of advance of the
strip The circuit for the electric induction heating coil 15 includes
a high frequency generator 23 which may be driven by any suitable
source of power and whose field winding is designated diagrammatically
at 24 The field winding 24 of the high frequency generator 23 is in
series with a suitable power source designated generally by reference
numeral 25 and a rheostat designated generally by reference numeral 26
which has a resistance element 26 a and a movable contactor 26 b The
movable contactor 26 b of the rheostat 26 may be moved along the
resistance element 26 a by means controlled by the speed of turning of
the variable speed line drive motor which drives the rolls 22 The
operative connection between the variable speed line drive motor and
the movable contactor of the rheostat is designated generally by
reference numeral 27 and may comprise mechanism well known to those
skilled in the art so that it is unnecessary to illustrate and

describe in detail such mechanism.
The rheostat controls the magnitude of current in the induction coils
in proportion to the speed of the strip The same result may be
accomplished by controlling the rheostat by the temperature of the
strip between the induction coils The rheostat may be operated
manually instead of automatically.
Thus when the strip slows down or stops the current to the induction
coils is reduced or shut off, the effect on the strip being
instantaneous, which is not true with any other type of heating In a
heating chamber even though the source of heat may be shut off the
strip is still subject to the established temperature in the chamber
until the chamber has time to cool Our method is foolproof; the
protective coating is not burned and the metal coating is not melted A
product of high quality and unprecedented uniformity is produced.
* Sitemap
* Accessibility
* Legal notice
* Terms of use
* 5.8.23.4; 93p

5161 5165.output

Recommended

Recommended

More Related Content

What's hot

What's hot (14)

Viewers also liked

Viewers also liked (19)

Similar to 5161 5165.output

Similar to 5161 5165.output (20)

More from j1075017

More from j1075017 (20)

Recently uploaded

Recently uploaded (20)

5161 5165.output