4271 4275.output

* GB784678 (A)
Description: GB784678 (A) ? 1957-10-16
Improvements in or relating to telephone systems
Description of GB784678 (A)
PATENT SPECIFICATION
Inventors: GERALD CURTIS and PETER RUSSELL ROBINSON 7845678A Date of
Application and filing Complete Specification May 18, 1956 '
No 15505/56.
Complete Specification Published Oct 16,1957.
Index at Acceptance: -Class 40 ( 4), KID, K 1 H(l B: 1 X: 3 A: 4: 18),
K 1 (J 3 B: J 6: L 9: T 5).
International Classification: -H 04 m.
COMPLETE SPECIFICATION
Improvements in or relating to Telephone Systems We, AUTOMATIC
TELEPHONE & ELECTRIC COMPANY LIMITED, Of Strowger Works, Liverpool, 7,
a British 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 1 rf and by the following
staternent: The present invention relates to telephone systems and is
more particularly concerned with private automatic branch exchanges
(p.a b x) serving large numbers of subscribers.
When it is required to provide a p a b x to serve a large number of
subscribers who may be dispersed in a number of geographically compact
groups, it is obviously uneconomic to bring every subscriber's line to
the site of the p.a b x, due to the cost of the line equipment.
However, if the Farent p a b x is located in one of the larger groups
and the remainder of the groups provided with satellite automatic
exchanges, each of which is provided with tielines to the parent p a b
x and other satellite exchanges, then a considerable economy in cost
and line equipment is afforded.
In such an arrangement of exchanges, all the incoming calls to the
parent p a b x from the national network exchange are answered by the
operator at the parent p a b x who then sets-up the connection to the
desired subscriber The operator may supervise the progress of a call

by listening to the audible tone signals, and withdraw from the
connection when the desired subscriber answers On the other hand in
periods of heavy traffic the operator having set-up the conditions to
obtain connection to the desired subscriber, may withdraw from the
connection before its completion in order to deal with other traffic,
the completion of the call then being accomplished by automatic means
In this event the operator supervises the call by means of an
indication given on a supervisory lamp associated with the particular
equipment employed by the operator in setting up the call The
arrangements for operating the supervisory lPrice 3 Ss,6 ddf S'd S
lamp are controlled by signals applied to a conductor other than a
speaking conductor It will be obvious that supervision within the p.a
b x presents no difficulties, but if an incoming main exchange call
requires connection to a subscriber on a satellite exchange, as the
tie-line is of the two-wire type, the supervisory indications which
are applied to a conductor other than a speaking conductor in the
satellite exchange must be suitably converted for transmission over
the tie-line to the p a b x.
where they must be re-converted to a suitable signal on the
supervisory control conductor in the p a b x.
The object of the present invention is to provide means whereby an
operator in a parent p.a b x can be provided with visual supervisory
indications of the progress of a call over a two-wire tie-line to a
subscriber on a satellite exchange when both the p a b x and, the
satellite exchange employ a conductor other than a speaking conductor
for supervisory control purposes.
According to the present invention a telephone exchange network is
provided comprising a parent private automatic branch exchange having
one or more satellite automatic exchanges wherein the present exchange
alone is provided with a manual board for setting-up calls incoming
from the national network or the like to subscribers served by the
parent and satellite exchanges, characterised in that the parent
exchange is connected to each satellite exchange by one or more
twowire tie-lines terminated at each end by relay sets, a relay set at
a satellite exchange being adapted, when involved in a connection from
the manual board to a satellite exchange subscriber, to be responsive
alternatively to signals indicative of the idle or busy condition of
the called line, said signal being received over a conductor other
than a speaking conductor and producing a distinctive signal at the
tieline, the latter signal comprising at least one reversal of the
potentials at the tie-line conductors.
s O According to a feature of the invention a relay set terminating a
tie-line at the parent exchange and involved in a connection from the
manual board to a satellite exchange subscriber is adapted to be

responsive alternatively io the beforementioned distinctive signals
applied to the tie-line and to transmit a suitably significant signal
over another conductor to the manual board to control a visual
supervisory indicator.
According to another feature of the invention the relay set at the
satellite exchange pro= duces a single reversal of potentials at the
tieline conductors when the called subscriber's line circuit is
encountered busy whereas it produces a reversal of prescribed duration
followed by another reversal of prescribed minimum duration when the
called subscriber's line circuit is encountered idle.
According to yet another feature of the invention when the called
subscriber answers a reversal of potentials is applied by the
satellite exchange switching equipment to the speaking conductors of
the satellite exchange relay set and thence to the conductors of the
tie-line, means within the relay set determining that the reversal at
the latter conductors shall not take place before the signalling cycle
appropriate to the idle line condition has been completed.
The details of the invention will be understood from the following
description of one method of carrying it into effect and should be
read in conjunction with the accompanying drawings comprising Figs 1-3
Of the drawings: Fig 1 is a trunking diagram of a portion of a large
parent p a b x having a number of satellite automatic exchanges, the
diagram being similar to Fig 1 of Specification No 771,485, the claims
of which are directed to the enquiry call feature.
The various types of call which the parent p.a b x caters for will now
be described with reference to the trunking diagram of Fig 1.
Firstly a call between subscribers within the p.a b x will be
outlined, say subscriber SB calls subscriber SA Upon subscriber SB
initiating a call, his line circuit LCB applies a marking to an idle
one of a plurality of line finders and selector hunt control circuits
such as FHC This marking first causes the selector hunter S
appropriate to said control circuit to take into use an idle group
selector, such as GS When the group selector has been seized the
control circuit causes the line finder LF of the control circuit FH-C
to connect with the calling line The group selector, which is of the
ten-level two-motion type, responds to the first dialled digit in
known manner and establishes a connection to an idle final selector,
such as FS, which is also of the two-motion type The final selectors
are of the 100-line type and obviously if levels 1 to 5 of the group
selectors give access, as shown, to final selectors the p a b x will
serve 5100 subscribers Connection to the required subscriber SA is
effected by the selected final selector responding to the dialled
second and third digits.
It is to be noted that the levels 6 to 8 of the 70 group selector GS

are utilised to give access to outgoing auto-to-auto relay sets, such
as OGAA It will be obvious to those skilled in the art that the
allocation of the group selector levels to tie-line TL traffic
restricts 75 the number of subscribers the p a b x can serve However
if a second stage of selection were incorporated between the existing
group and final selectors, both the subscriber and the tie-line
capacities of the p a b x would be 80 substantially increased.
Two classes of subscriber are catered for by the p a b x, namely those
who are permitted to dial directly to the main exchange and those who
must obtain assistance of the manual 85 board operator for the purpose
of setting-up main exchange connections, discrimination being effected
in accordance with a class of service signal derived from the
subscriber's line circuit In the case of an exchange call 90 from the
first type of subscriber say SB, upon initiation of the call the
subscriber is connected over the line finder LF, the finder/ hunter
control MHC and the selector hunter SH to a group selector GS The
privileged 95 subscriber thereupon dials the outgoing digit i O " in
the present case) which connects him to an idle exchange line circuit,
and subsequent digits are repeated by the latter to the main exchange
Direct access to the exchange 100 line circuit is barred to the second
class of subscribers who must dial digit " 9 " to gain access to the
manual board over a group selector In this case an assistance circuit
AC is taken into use over group selector level 9, 105 and this marks
the appropriate position on the exchange line finder multiple and
causes an individual calling lamp AL to light on the manual board The
operator completes a conversational path to the subscriber by way of a
11 C connecting circuit CC, ascertains his requirements and his own p
a b x number, and then requests him to clear Thereupon the operator
operates a connect key relevant to an idle connect circuit CC and a
call key which 115 enables the operator to obtain access to an idle
exchange line circuit by way of an exchange line finder ELF The
operator is then connected over the exchange line circuit to the main
exchange and proceeds to set up 12 ( the connection to the required
subscriber.
When that subscriber has answered the operator applies a holding
condition -to the exchange line and thein sets up a connection over a
normal path NP as though the call were 12; an incoming call, and
ultimately clears from the connection.
It is to be noted that the manual board is provided with an individual
line circuit LCO which like the subscribers' line circuits termin 13 C
784,678 784,678 ates upon the line finder LF multiple, for use in
local calls from the operator to p a b x.
subscribers.
The parent p a b x may be served by say 50 bothway lines MEL to the

main exchange, and each of these terminates upon a separate exchange
line circuit ELC When a main exchange call is made to the parent p a b
x.
the application of ringing current to an exchange line circuit causes
the latter to flash the exchange calling lamp CL on the manual board
MB Thereupon the manual board operator operates a connect key (not
shown) associated with an idle connect circuit such as CC, together
with an exchange answer key (not shown) The latter key enables the
exchange line circuit to be marked on the bank of the exchange line
finder ELF, while the former key causes the exchange line finder, for
example a 50-point non-homing uniselector individual to the chosen
connect circuit, to hunt for the marked exchange line circuit.
When the manual board is connected by the exchange line finder to the
exchange line circuit, the supervisory lamp SL associated with the
operated connect key is lit, and the ringing from the main exchange is
tripped by the loop applied from the manual board circuit.
The operator may now ascertain the number of the subscriber required
by the main exchange call, and set up a connection to that number.
At this point it should be noted that each of the exchange line
circuits is accessible over two paths from a uniselector finder
multiple, the uniselector finders such as ATF and BTF in the multiple
each being associated with separate control circuits such as ATFC and
BT 1 FC The two paths which are derived from successive positions on
each finder bank, and are designated EP and NP, will be referred to as
the enquiry path and the normal path respectively.
In the present case the operator applies a condition to the exchange
line circuit whereby an artificial holding loop is applied to the
exchange line which is also isolated Furthermore, a marking is
connected to the associated path NP and a starting condition is
applied to an idle trunk finder control, the latter causing the finder
to connect with the exchange line circuit over the marked normal path
Each trunk finder control circuit is permanently associated with a
trunk group selector TGS, and the operator is therefore enabled to
dial the p.a b x number, the call being set up over a trunk group
selector and final selector in known manner It will be observed that
levels appropriate to p a b x numbers on the group selectors GS and
the trunk group selectors TGS are multipled Also it will be seen that
the levels appropriate to outgoing tie-lines are multipled between the
group selectors and the trunk group selectors, although access to the
tie-lines TL may depend on the class of service provided for a
particular p a b x subscriber.
The enquiry facility provided by the p a b x.
will now be outlined with reference to an incoming call set up to a p
a b x subscriber As already mentioned, the call from the main 70

exchange is completed over an exchange line circuit and a normal path
NP When the p.a b x subscriber wishes to make an internal enquiry
call, he momentarily actuates a pushkey or other means associated with
his instru 75 ment and this passes a signal back to the exchange line
circuit which introduces an artificial hold loop into the exchange
line and isolates said line The exchange line circuit also applies a
marking potential to the enquiry 80 outlets of the trunk line finder
multiple which are related to the normal path NP employed on the
present call Moreover the operation of said key causes a start
condition to be applied to an idle trunk finder control circuit such
as 85 BTFC which is thereupon connected to the enquiry path over the
associated trunk finder BTF Since said control circuit terminates upon
a trunk group selector, the p a b x subscriber may dial the wanted
party, the 90 exchange line circuit functioning as an impulse repeater
for setting-up the connection over said trunk group selector and a
final selector It should be noted that the call between the two p.a b
x parties involves two selector trains 95 each with a trunk finder and
control circuit together with an exchange line circuit.
Two possibilities now arise namely: the original p a b x subscriber
may wish to revert to the main exchange connection or he may 100 wish
to transfer the call to the p a b x subscriber he has called In the
first case the original subscriber again actuates his push key and
this results in the breaking down of the connection involving the
enquiry path, and also 105 in the re-establishment of the original
connection to the main exchange On the other hand if transfer of the
call is to be effected the original p a b x subscriber replaces his
receiver This causes the exchange line cir 110 cuit to bring about the
release of the trunk finder control circuit, the trunk group selector
and the final selector providing connection to the original p a b x
subscriber The exchange line circuit now extends a condition over the
115 enquiry path to cause the relevant finder to advance its wipers
one position so that they connect with the normal path NP, and it is
this path which completes the conversational connection between the
main exchange party and 120 the second p a b x subscriber The latter
subscriber may, if need be effect further transfer of the call in
precisely the manner described.
In the event of a call originated by any class of p a b x subscriber
to the main exchange the 125 setting up of an enquiry call and
possible transfer of the main exchange subscriber to a second p.a b x
subscriber may be effected along the lines described above.
A feature of this p a b x is that it is provided 130 with a number of
satellite automatic exchanges the outlets of certain levels of the
group selector GS in the p a b x giving access by way of outgoing
auto-to-auto relay sets, such as OGAA, to two-wire tie-lines extending

to the satellite automatic exchanges It is to be noted that all
national network calls incoming to the parent p.a b x and the
satellite exchanges are controlled by the operator at tile parent p a
b x A call from the national net Lwork exchange to a subscriber such
as SSA on a satellite exchange will now be outlined The procedure by
the operator is as previously described up to the point where the
operator dials into the trunk group selector The latter is now dialled
up to the level giving access to the desired satellite exchange, a
free outlet on that level being selected in well known manner When the
trunk group selector extends the loop, the outgoing auto-to-auto relay
set is seized and results in a further loop being extended over the
tieline through the incoming auto-to-auto relay set ICAA, to the
incoming group selector ICGS, which is seized The p a b x operator now
dials the satellite exchange number of subscriber SSA and the group
selector ICGS and final selector SFS respond accordingly When the
final selector has been set by the last two digits of subscriber's
number, the idle or busy condition of the subscriber's line circuit
SLCA must be returned to the p a b x.
operator.
At this juncture it is convenient to outline the operating procedure
of the p a b x operator.
On a p a b x an operator may be required to deal with heavy incoming
and outgoing traffic, and consequently will not be able to aftord the
time personally to supervise the progress of a particular call by
means of the audible tone signals For this reason each of the connect
circuits is provided with an individual supervisory lamp and by means
of various rates of flashing or a permanent glow, the progress and
condition of a call can be visually ascertained This enables the
operator to deal with further calls during the time a particular call
is being answered On particularly busy p.a b x's a further reduction
in the setting up time of a call can be effected by the use of a key
sender (not shown) which enables the operator to operate in turn
puslh-type keys appropriate to the digits of the subscriber's number
When the last digit has been keyed the operation of a further
push-type key enables the key sender cicuit to transmit automatically
the number of impulses appropriate to the various digits keyed Hence
the operator is free to deal with other calls while the particular
call is being set up, its progress and condition being indicated on
the relevant connect circuit supervisory lamp.
In order to effect the visual supervision, a conductor other than a
speech conductor is employed to enable the connect circuit to give the
relevant supervisory lamp indication if a stage should be encountered
busy or the required subscriber is idle or busy.
On a call within the p a b x supervision presents no difficulty but

when a call is made to a satellite exchange over a tie-line which is
70 of the two-wire type, the conditions applied to the supervisory
conductor in the satellite exchange must be converted by the incoming
auto-to-auto relay set for transmission over the two-wire tie-line The
outgoing auto-to-auto 75 relay set at the p a b x re-converts the
signal applied to the tie-line by the incoming' auto-to-auto relay set
into an indication on the additional conductor in the p a b x
resulting in the displaying of the appropriate indica 80 tion on the
supervisory lamp associated with the connect circuit In order to give
the parent p.a b x operator a lamp indication of the progress of a
call to subscriber on a satellite exchange, three conditions must be
catered for, 85 namely, subscriber idle and being rung, subscriber
answers, and subscriber busy.
A call by subscriber on the parent p a b x to a subscriber on the
satellite exchange will now be outlined, say p a b x subscriber SB
calls 90 satellite exchange subscriber SSA Upon subscriber SB
initiating the call, his line circuit LCB applies a marking to an idle
line finder and selected hunt control circuit, such as FHC.
This causes the selector hunter SH to take into 95 use an idle group
selector, such as GS When the group selector has been seized the
control circuit causes the line finder LF of the control circuit FHC
to connect with the calling line Subscriber SB now dials the digit
appro 100 priate to the group selector level giving access to
tie-lines extending to the particular satellite exchange in which
subscriber SSA is located Upon the location of an idle tie-line in
that level, an outgoing auto-to-auto relay set 105 is seized, such as
OGAA, which in turn causes the seizure of the incoming group selector
ICGS by way of the incoming auto-to-auto relay set ICAA Further
dialled digits from the parent p a b x subscriber cause the group 110
selector SGS and final selector SFS to respond accordingly When the
final selector SFS has been set by the last two digits of the
satellite exchange subscriber's number, the idle or busy condition of
his line circuit SLCA is indicated 115 to the p a b x subscriber by an
appropriate audible tone returned by the final selector SFS.
A call incoming from the national network exchange to the parent p a b
x and requiring 12 C connection to a subscriber on a satellite
exchange will now be described in more detail reference being made to
Figs 2 and 3 of the accompanying drawings The p a b x operator having
ascertained the number of the subscriber 125 required by the incoming
call, proceeds in the manner already described to set-up the
connection to the satellite exchange subscriber The first digit
dialled by the operator positions the trunk group selector TGS on the
level giving 13 C 784,678 effective in the incoming relay set, and
thus its operation is not detrimental No further change takes place in

the outgoing auto-to-auto relay set until the commencement of the
impulses requiring repetition over the tie-line 70 to set up the
required selectors in the satellite exchange.
Reference will now be made to the satellite exchange and the operation
of the incoming relay set in response to the seizing of its asso 75
ciated group selector ICGS by the loop applied to the tie-line
conductors and + The path of the tie-line conductor and + extends '
through the low resistance upper and lower windings of relay ATA,
which are differentially 80 connected, to the and + leads of the
incoming group selector ICGS, resulting in the preparation of the
latter to receive the impulses of the next digit to be dialled by the
p a b x.
operator Before the incoming group selector 85 applies an earth to its
P lead (ICGS), the previously mentioned unbalancing of the tie-line
conductors by the outgoing relay set, enables the differentially
connected relay ATA to operate, and thus when the incoming group 90
selector applies earth to the P lead (ICGS) it is effective in
operating relay ATB over its upper winding, by way of contacts ATA 1,
AE 52 and HF 4 Relay ATB operating, at contacts ATB 2 operates the
slow-to-operate 95 relay HF through contacts AOP 6 and AE 53, at
contacts ATB 3 completes a holding circuit for its lower winding to
the P lead (ICGS), and at contacts ATB 4 connects the serially
connected windings of relays AES and ABS 100 to the D lead (ICGS)
Relay HF operating, at contacts HF 1 and HF 3 short-circuits the upper
and lower windings of relay ATA, which releases without effect Thus
there is now a direct circuit between the tie-line con 105 ductors and
+ and the leads and + of the incoming group selector ICGS Contacts HF
2 operate relay X, but it is not effective at this time, and contacts
HF 4 break a point in the original operating path of relay ATB 110
While the incoming group selector ICGS and the final selector SFS are
responding to the digits appropriate to the desired subscriber's
number, no further change takes place in the incoming auto-to-auto
relay set 115 until the final selector SFS is positioned so as to test
the line circuit of the required subscriber for the idle or busy
condition There is one exception to this however, and that is if the
group selector encounters all final selectors 120 on the desired level
busy In this case the' group selector applies a resistance earth to
the lead D (ICGS) to cause the incoming relay set to respond and
enable the busy indication to be given to the p a b x operator The 125
response of the incoming auto-to-auto relay set ICAA to this condition
will be described later as it is identical with the indication
required if the desired subscriber is busy.
Referring again to the outgoing auto-to-auto 130 access to tie-lines
connected to the desired satellite exchange Each of the tie-lines TL

terminates in the parent p a b x on an outgoing auto-to-auto relay set
such as OGAA, and in the satellite exchange the tie-line TL terminates
on an incoming auto-to-auto relay set such as ICAA During the rotary
movement of the trunk group selector over the desired level, the first
idle outgoing auto-to-auto relay set encountered causes the rotary
movement of the group selector to cease and the seizing of the relay
set The idle condition of the outgoing relay set is indicated by the
presence of battery, through resistor R 1, on the P lead of the group
selector multiple GSM.
When the outgoing auto-to-auto relay set is seized, the loop from the
operator's circuit is extended by the trunk group selector to the
leads and + of the group selector multiple GSM, resulting in the
operation of high-speed type impulsing relay A At the same time a path
orginating in the connect circuit employed on the call is extended by
the trunk group selector to the lead D (GSM) In the connect circuit
this path includes relays which control the operation of the
associated supervisory lamp, and at the time of seizing the outgoing
auto-to-auto relay set, a resistance battery is presented to the lead
D With the operation of relay A to the loop provided by the p a b x.
operator, its contacts Al complete a further loop by way of the
forward conducting rectifier MR 1 over the conductors and + of the
tie-lin TL to seize, at the satellite exchange, the incoming group
selelector ICGS through the incoming auto-to-auto relay set ICAA
Contacts A 2, first remove a short-circuit from relay B, and then
provide the earth to operate it in series with resistor R 2 Relay B
operating, at contacts Bl applies earth to the timing circuit
involving capacitor C 11 and resistor R 3 in conjunction with relay
TB, which operates after a delay The use of the timing circuit will
become apparent during the release of the outgoing auto-to-auto relay
set later in the description Contacts B 3 first remove the battery
through resistor R 1 from the P lead and then replace it by an earth
to guard the outgoing auto-to-auto relay set against intrusion by
other selectors hunting over that level of the group selector multiple
GSM Finally contacts B 4 complete the circuit to operate relay TA over
its upper winding to the resistance battery on the lead D Relay TA
operating, at its first-to-operate contacts TA 4 completes a holding
circuit over its lower winding to the earth at contacts B 2, at
contacts TA 3 first disconnects the original operating path for relay
TA, and then completes the circuit to connect the earth of contacts TB
1 to the tieline conductors and + thereby unbalancing them When relay
TB eventually operates, contacts TB 1 remove the unbalancing earth off
the tie-line conductors and +, but meantime the unbalance condition
will have been 784,678 784,678 relay set, which at the present time is
conditioned to repeat the digits corresponding to the desired

subscriber's number over the tie-line to the selectors in the
satellite exchange, upon the " break " portion of the first impulse of
a digit relay A releases, at contacts Al breaks the loop applied to
the tie-line conductors and + Contacts A 2 releasing, first remove the
short-circuit from the upper winding of relay CD, and then complete a
short-circuit for relay B Relay CD operates by way of battery,
resistor R 2, contacts OP 3, A 2, B 5 to earth over its upper winding
Contacts CD 1 prepare a non-resistive impulsing loop for the tie-line
conductors and + When relay A re-operates to the "make" portion of the
first impulse, contacts Al now complete thenon-resistive loop to the
tie-line conductors by way of contacts CD 1 and A 56, and at contacts
A 2 first removes the short-circuit from relay B and then
short-circuit the upper winding of relay CD This sequence is repeated
for each impulse of a digit, relay B holding during the " break "
period of the impulses, and relay CD holding during the "make" period
of the impulses, due to their respective slow-to-release
characteristics because of the short-circuit applied to their windings
However when all the impulses of the digit have been transmitted,
relay A remains operated, and thus the short-circuit on the upper
winding of relay CD is sustained resulting in its release.
When all the digits of the required subscriber's number have been
transmitted over the tie-line to the satellite exchange, the last
digit of the number positions the final selector SFS so that it is
able to test the required subscriber's line circuit for the idle or
busy condition The result of this testing operation by the final
selector SFS is indicated on a path originating in, and extending from
the incoming auto-to-auto relay set ICAA, namely the D lead, the idle
condition of the desired subscriber's line circuit being denoted by a
full earth, while the busy condition is denoted by a high resistance
earth.
Taking the case where the subscriber's line circuit is found to be
busy, the value of the high resistance earth connected to the D lead
(ICGS) is so arranged that only the slow-tooperate relay ABS can
operate although it is in series with the lower winding of relay AES.
Relay ABS operating, at contacts AB 52 and AB 53 reverses the
potential of the tie-line conductors.
The reversal of the tie-line conductors in the incoming auto-to-auto
relay set is indicated in the outgoing relay set by the operation of
relay D in series with rectifier MR 2 Relay D operating, at contacts D
1 completes the circuit to operate the slow-to-release relay DD Relay
DD operating, at contacts DD 4 completes the circuit to operate the
slow-tooperate relay BS over its lower winding by way of earth,
contacts B 2, OP 6, PF 1, DD 4, TA 5 and E 52 The operation of relay
BS, at contacts B 52 connec Cs earth by way of resistor R 8 to the D

lead of the group selector multiple GSM As has been men 70 tioned
previously the D lead (GSM) originates in the particular connect
circuit being used on the call, and consequently this high resistance
earth enables the connect circuit to respond accordingly resulting in
the super 75 visory lamp being caused to flash on and off at the rate
that indicates a busy line.
As has been mentioned previously, the busy indication may be
originated by two conditions, namely, subscriber busy, or failure to
80 complete the routing of the call due to all equipments in a
particular stage being encountered busy The p a b x operator, on the
receipt of a busy indication will attenpt to trunk offer as the lamp
indication for both 85 conditions are identical Trunk offering will
obviously only be succenssful if the routing of the operator's cell
has been completed correctly to the desired subscriber's line, when
the operator will be able to interrupt the exist 90 ing conversation
and request the unwanted party to clear If the busy indication had
originated from a busy stage, then even though the trunk cifet had
been mad-, the busy indication would persist and the operator 95 would
act accordingly.
To trunk offer it is necessary for the operator to dial a further
digit, for example digit 0 Relay A, in the outgoing relay set responds
thereto, at contacts A 2 enabling relay CD to 100 operate, and at
contacts Al repeating the impulses to the tie-line Relay CD operating,
at contacts CD 1 completes a low resistance loop for the tie-line
while impulsing takes place, and also short-circuits relay D which 105
releases, and at contacts CD 2 completes the circuit to charge
capacitor C 5 through resistor R 9 to the earth at contacts B 53
Contacts CD 4 complete a circuit to hold relay DD operated by way of
earth, contacts A 54 and 110 DD 1, when relay D releases Upon the
completion of the trunk offer digit relay CD releases, at contacts CD
2 completing the discharge path for capacitor CS through the winding
of relay PFE The value of resistor 115 R 9 is so chosen that the digit
dialled ensures that relay CD must remain operated for a period
sufficiently long enough to give capacitor CS a charge that will
operate relay PF In this way, it is possible to ensure that 120 relay
PF will only operate to a digit having a number of impulses
approaching that of digit 0 Contacts CD 4 releasing break the holding
circuit for the slow-to-release relay DD, which thus releases after a
delay Relay PF operat 125 ing, at its first to operate contacts PF 4
provides a self-holding circuit to the earth at contacts B 53, at
contacts PF 1 breaks the circuit to the lower winding of relay BS,
thus causing it to release, and at contacts 130 SFS) to ensure it
remains held while it is disconnected from the tie-line conductors The
operation of relay LABS, at contacts AB 52 and AB 53 reverses the

potentials on the tieline conductors 70 After its slow-to-release
delay, relay X eventually releases, at contacts XI breaking the
holding circuit of the slow-to-release relay Z, which commences to
release, and at contacts X 2 and X 3 restores the potential of the 75
tie-line conductors to normal Relay Z releasing at the end of its
slow-to-release delay, at contacts Z 1 restores the series holding
circuit for relays ABS and AES to the D lead ICGS, and at contacts Z 2
and Z 4 first disconnects the 80 resistor R 4 and R 5 from the and +
tie-line conductors, respectively and then completes once again the
path from the tie-line conductors to the and + leads ICGS which now
extend to the final selector (SFS) Con 85 tacts Z 3 disconnect the
circuit for resistor R 6 across the and + leads ICGS, thereby making
the holding of the final selector (SFS) dependent on the loop applied
at the end of the tie-line by the outgoing auto-to-auto relay 90 set
It will thus be seen that a signal has been transmitted over the
tie-line conductors to signify that the desired subscriber's line
circuit has been encountered idle by the final selector SFS 95
Reverting again to the outgoing auto-to-auto relay set, before the
reversal of the potentials of the tie-line conductors takes place
relays A, B, TA and TB, are operated Upon the reversal of the
potentials of the tie-line con 100 ductors, relay D operates in series
with rectifier MR 2, and operates relays DD and BS as before described
When the tie-line potentials are restored to normal by the release of
relay X in the incoming auto-t G-auto relay set, relay 105 D in the
outgoing relay set also releases.
Contacts D 1 release the slow-to-release relay DD which at contacts DD
4 completes the circuit to operate the slow-to-operate relay ES over
its upper winding in series with the 110 upper winding of relay BS,
which thus remains held Relay ES operating, at contacts ESI completes
a self-holding path to its upper winding and also short-circuits the
upper winding of relay BS which releases with 115 out effect Contacts
E 52 first disconnect the original operate path of relay BS and then
prepare a path to operate the slow-to Hoperate relay AS in series with
the lower winding of relay ES Contacts E 53 complete the circuit 120
to connect earth to the D lead (GSM) thereby enabling the connect
circuit to respond and cause its associated supervisory lamp to glow
permanently, indicating to the p a b x operator that the final
selector in the satellite exchange 125 has encountered the desired
subscriber's line circuit in the idle condition.
It is to be noted that the combined slow release times of relays X and
Z ensure that even if the desired subscriber should answer 130 PF 3
first disconnects the operating circuit of relay PF and then completes
a path to make the release of relay PF dependent on relay DD at
contacts DD 3 Relay BS releasing, at contacts B 52 disconnects the

resistor R 8 from the lead D (GSM), thereby enabling the connect
circuit to respond resulting in the cancellation of busy supervisory
indication.
Contacts B 53 remove the earth from resistor R 9 and also disconnect a
possible holding circuit of relay PF making its holding dependent on
contacts DD 3 The relay DD now releases after its delay, and at
contacts DD 3 releases relay PF The operator may now converse with the
wanted subscriber, and no further change takes place until the
subscriber idle signal is returned over the tie-line by the incoming
auto-to-auto relay set at the satellite exchange.
In the satellite exchange the dialling of the trunk offer digit
enables the final selector to respond, and complete a circuit to
enable the p.a b x operator to speak to the wanted subscriber In
responding the final selector also causes the high resistance earth
applied to the D lead (ICGS) to be removed, thus releasing relay ABS
in the incoming relay set Relay ABS releasing, at contacts AB 52 and
AB 53 restores the potentials applied to the tie-line to normal When
the wanted subscriber clears the final selector responds and switches
to the now idle line circuit The operation is now the same as for an
idle line.
Referring now to the case where the final selector SFS encounters the
desired subscriber's line circuit idle, a full earth is returned on
the D lead to the incoming autoto-auto relay set, resulting in the
operation of relay AES and the slow-to-operate relay ABS over their
series connected windings At this time relays HF, ATB and X are
operated Relay AES operating, at contacts AE 51 completes a holding
circuit for itself over its upper winding, at contacts AE 52 prepares
the path to operate relay AOP, and at contacts AE 53 breaks a point in
the holding path of relay HF, but this is restored by the contacts AB
51 when relay ABS operates.
Contacts A E 54 first break the circuit to the slow-to-release relay
X, which commences to release, and then complete the circuit to
operate the slow-to-release relay Z by way of contacts XI Relay Z
operating, at contacts Z 1 first disconnects the series operating path
of relay ABS and AES and then applies holding earth for them, at
contacts Z 2 and Z 4 first disconnects the path of the tie-line
conductors from the and + leads ICGS extending to the final selector
SFS, and then connects the tie-line conductors and + to resistors R 4
and R 5 respectively, resistor RA being connected to battery and
resistor R 5 being connected to earth Contacts Z 3 provide a loop,
through resistor R 6, across the and + leads ICGS extending to the
final selector 784,678 784,678 almost immediately upon hearing the
ringing of his instrument bell, the subscriber idle signal namely the
reversed and the following normal period of the tie-line conductor

potentials are guaranteed by relays X and Z respectively Although the
final selector itself has reversed the potentials on leads and +
(ICGS), and removed the battery condition from lead D (ICGS), relay
ABS remains held in series with relay AES by contacts Z 1 until the
relay Z completes its release With the release of relay Z, the
reversed potentials of leads and + (ICGS) are connected to the
tie-line conductors.
When the subscriber finally answers, the final selector (SFS) responds
accordingly, resulting in the reversal of potentials of the leads and
+ (ICGS) and as there is a direct path through the incoming
auto-to-auto tray set to the tie-line conductors and + it is obvious
that their potentials are also reversed.
The final selector also removes the earth from the lead D (ICGS) and
replaces it by a battery through a winding of one of its relays.
Due to the removal of the earth from the lead D (ICGS), relay ABS is
caused to release, relay AES remaining held over its upper winding to
the earth at contacts ATB 1 Relay ABS releasing, at contact ABSI
breaks the circuit to relay HF which releases Contacts AB 52 and AB 53
releasing at this time do not affect the polarity of the tie-line
conductors as relay X is already released Relay HF releasing, at
contacts HFI and HF 3 removes a short-circuit from the windings of
relay ATA so that once again each of the windings is in series with
the path to the tie-line conductors and +.
With the second reversal of the potential of the tie-line conductors,
this time by the final selector in the satellite exchange, relay D is
the outgoing auto-to-auto relay set responds accordingly, and at
contacts D 1 operates relay DD Relay DD operating, at contacts DD 2
prepares a path to the lower winding of relay CD, and at contacts DD 4
completes the circuit by way of contacts TA 5 and E 52 to operate the
slow-to-operate relay AS over its lower winding in series with the
lower winding of relay ES Relay AS operating, at contacts ASI
completes a self-holding circuit for its upper winding by way of
contacts T Al, OP 6 and B 2 to earth, and at contacts A 52 first
removes the earth from the D lead (GSM) and then connects to it the
lower winding of relay CD.
Contacts A 53 and ASS reverse the potentials of the leads and + of the
group selector multiple GSM, and contacts A 56 prepare a point in the
path to connect earth to the conductor of the tie-line conductors.
Upon the removal of the earth from the D lead (GSM) the connect
circuit is enabled to respond, resulting in the extinguishing of its
associated supervisory lamp, thereby indicating to the p a b x
operator that the subscriber has answered.
If the p a b x operator has remained in control of the call, the
procedure for withdrawing from the connection may be commenced result

70 ing in the release of the connect circuit and the connecting of the
exchange line circuit into the call once again On the other hand if,
in order to deal with other calls, the p a b x operator had decided to
withdraw from the connection 75 earlier, and to depend on the usual
signals from the relevant connect circuit supervisory lamp, the
connect circuit is also enabled to bring about its release from the
connection automatically upon the extinguishing of the super 80 visory
lamp This also results in the connection of the exchange line circuit
into the call once again In responding, the connect circuit removes
the battery condition from the D lead (GSM) and replaces it with an
earth condition 85 which is effective in the outgoing auto-to-auto
relay set in causing the operation of relay CD Relay CD operating, at
contacts CD 1 completes the circuit to connect earth to the conductor
of the tie-line conductors thereby 90 unbalancing them.
The effect in the incoming auto-to-auto relay set of the unbalancing
of the tie-line conductors by the outgoing relay set, results in the
operation of relay ATA once again, which at con 95 tacts AT Al
completes the circuit to operate relay AOP over its upper winding
Relay AOP operating, at contacts AOP 4 completes a selfholding path
for its lower winding from the earth at contacts ATBI, and releases
relay 100 AES Contacts AOPL disconnect the direct path of the +
conductor of the tie-line conductors, while contacts AOP 5 first
disconnect the direct path of the conductors of the tieline
conductors, and then completes a point 105 in the path to the loop
provided by the seriesconnected left-hand windings of transformer TR 2
Further, contacts AOP 2 and AOP 3 first disconnect the path of the and
+ leads (ICGS) from the direct path to the tie-line con 110 ductors
and then completes the path to connect them to battery and earth
respectively, by way of the right-hand windings of transformer TR 2,
the windings of relays DF and AA, and the barretter BR 2 Contacts AOP
6 115 breaks a point in the operate path of relay HF to prevent its
operation when relay AES releases.
It will be recalled that when the subscriber answered the potentials
of the leads and + 120 (ICGS) were reversed in, and by the final
selector and hence relay AA is enabled to operate to this condition It
should be noted that relay DF does not operate at this time as its
windings are differentially connected Relay 125 AA operating, at
contacts AA 1 completes the loop on the tie-line conductors through
the series connected left-hand windings of transformer TR 2, and at
contacts AA 2 first removes a short-circuit from relay AB and then pro
130 784,678 vides the earth to enable it to operate in series with
resistor R 7 The operation of relay AB at contacts ABI first breaks
the path to the i series-connected windings of relays AES and 1 ABS,
and then connects earth to the D lead (ICGS) Contacts AB 2 prepare a

point in the path to operate relay ACD in series resistor R 7, but at
present it remains unoperated due to the short circuit earth applied
by contacts AA 2.
When the earth is applied to the D lead (ICGS) by contacts AB 1, it
enables the final selector to respond and results in the operation of
a relay therein, which first removes the speaking battery feeding
transmission bridge in the final selector from the connection and then
completes a direct path from the subscriber's line circuit over the
selector wipers to the speaking battery feeding transmission bridge
provided by the incoming auto-to-auto relay set This transmission
bridge is formed by transformer TR 2, capacitor C 4, the speaking
battery feed for the subscriber now being provided by way of the
barretter BR 2 and the windings of relays AA and DF With conversation
ready to take place the following relays are operated, namely relays
AA, AB, ATB and AOP.
Consequent upon the removal of the battery and earth potentials from
the tie-line conductors by the operation of relay AOP in the incoming
auto-to-auto relay set, relay D in the outgoing auto-to-auto relay set
is caused to release, and at contacts D 1 releases relay DD Relay DD
releasing, at contacts DD 2 first releases relay CD and then operates
relay OP Relay OP operating, at contacts O Pl completes a self-holding
path to the D lead (GSM) and at contacts OP 2, OP 5, OP 4 and OP 7
first ensures the removal of the battery feeding transmission bridge
formed by transformer TR 1, capacitors C 2 and C 3, the barretter BR
1, and the windings of relay A, from the leads and + GSM, resulting in
relay A releasing and then they complete the path for connecting the
tieline conductors directly to the leads and + (GSM) Contacts 01 P 6
remove the holding earth from relays ES and AS, which release, and
contacts OP 3 ensure that relay B remains held when relay A releases
Relays CD, ES, AS, release without effect The outgoing relay set is
now ready for conversation to take place, and at this time relays TA,
TB, OP and B are operated.
It will be recalled that when the subscriber answered the connect
circuit replaced the battery condition on the D lead (GSM) by an earth
condition, and also released and re-introduced the exchange line
circuit into the call.
When the re-introduction of the exchange line circuit has been
completed, a battery feeding transmission bridge is connected to the
leads extending to the tie-line conductors At the same time, the
exchange line circuit applies an earth to the lead extending to the D
lead GSM) to ensure that relay OP remains operated when the connect
circuit releases Thus i can be seen that on termination of the call he
release of the outgoing auto-to-auto relay et is dependent on the
exchange line circuit 70 Upon the termination of the call the

satellite exchange subscriber replaces his receiver, resulting in the
disconnection of the loop to which relay AA in the incoming relay set
was holding Relay AA releasing, at contacts AA 1 75 disconnects the
loop, provided by the seriesconnected left-hand windings of
transformer TR 2, across the tie-line conductors Contacts AA 2
short-circuit relay AB which releases after a delay, the contacts AA 2
releas 80 ing also enable relay ACD to operate for the slow-to-release
time of relay AB, but however its operation is of no consequence at
this time.
Relay AB releasing, at contacts AB 1 removes the earth fom the lead D
(ICGS) which extends 85 to the final selector As a result of the
removal of this earth the final selector is enabled to release, and in
turn enables the group selector ICGS to release The latter results in
the removal of the earth from the P lead (ICGS), 90 thereby releasing
relay ATB and AOP in the incoming relay set With the release of these
relays, the incoming auto-to-auto relay set is returned to the idle
condition, and is available for use when the outgoing relay set also
returns 95 to the idle condition.
When the incoming relay set removes the loop across the tie-line
conductors, the exchange line circuit is enabled to release and this
results in the removal of the earth 100 from the D lead GSM, thereby
releasing relay OP Relay OP releasing, at contacts O Pl breaks its
self-holding path to thr D lead (GSM), and at contacts O P 3, OP 7, OP
2 and OP 5 first disconnect the direct path of leads 105 and + GSM to
the tie-line conductors, and then reintroduce the battery feeding
transmission bridge involving transformer TR 1, once again Contacts OP
3 releasing, complete the short-circuit for relay B which also 110
releases after a delay At this time a path is also completed by way of
contacts B 5, A 2 and OP 3 to operate relay CD over its upper winding
in series with resistor R 2, but its operation, during the
slow-to-release time of relay B is of 115 no effect Relay B releasing,
at contacts BE removes an earth from the timing circuit involving
capacitor Cl, resistor R 3 and relay TB, at contacts B 2 removes the
holding earth from the lower winding of relay TA, which 120 releases,
and at contacts B 3 first disconnects the earth from the P lead (GSM)
and then prepares a point in the path to resistor R 1.
Contacts B 5 break the holding circuit for the upper winding of relay
CD, thereby enabling 125 it to release Relay TA releasing, at contacts
TA 2 removes the earth from the timing circuit, thereby enabling relay
TB to release after a delay, which is determined by the capacitor Cl
and resistor R 3 The delay is so arranged 13 Q 784,678 as to cover the
release of all the equipment employed on the call in the satellite
exchange.
When relay TB finally releases its contacts TB 2 complete the path to

connect battery by way of resistor R 1 to the P lead (GS Mi), thereby
indicating that the tie-line is now available for use on a further
call.
It may be mentioned that on a call from the main exchange, through the
parent p a b x.
to a satellite exchange subscriber, the latter is provided with means
to initiate an enquiry call and if required transfer the main exchange
call to another subscriber within the network of private exchanges To
initiate an enquiry call the satellite exchange subscriber presses a
push-button associated with the telephone instrument This push-button
applies an earth to the speaking conductors, thereby unbalancing them,
and as relay DF in the incoming auto-to-auto relay set has its
windings differentially connected, the unbalancing of the speaking
conductor enables it to operate Relay DF operating, at contacts D Fl
applies an earth to the + tie-line conductor and accordingly
unbalances the tie-line The exchange line circuit responds to this
unbalance and causes a holding loop to be applied to the main exchange
line, and also establishes connection over the enquiry outlet of the
exchange line circuit, and then by way of a further trunk line finder
to another trunk group selector The satellite subscriber may now dial
the digits appropriate to the enquiry subscriber, relay AA in the
incoming auto-to-auto relay set responding, and at contacts AA 1
repeating the impulses over the tie-line to the exchange line circuit
in the p.a b x Upon establishing connection to the enquiry subscriber,
the satellite exchange subscriber may transfer the call to the enquiry
subscriber by clearing from the connection causing : the exchange line
circuit to respond and co mplete the connection from the main exchange
line to the enquiry subscriber On the other hand if only an enquiry
call is made, then when the enquiry subscriber clears, the exchange
line circuit responds and causes the re-establishment of the original
connection to the main exchange.
A call from a p a b x subscriber to a satellite exchange subscriber
will now be given in more detail The p a b x subscriber having dialled
the group selector to the level giving access to tie-lines extending
to the satellite exchange in which the required subscriber is located,
seizes the first idle outgoing auto-toauto relay set on that level The
idle condition of the outgoing relay set is indicated by battery
through resistor R 1 being connected to the P lead (GSM) The group
selector extends a loop to the leads and + (GSM) thereby operating
relay A Relay A operating, at contacts Al completes the loop on the
tieline conductor, causing the seizure of the group selector (SGS) by
way of the incoming auto-toauto relay set in the satellite exchange
Contacts A 2 operate relay B in series with resistor R 2 Relay B
operating, at contacts Bl completes the circuit to operate relay TB,

at contacts B 3 connects earth to the P lead (GSM) to guard the
outgoing relay set against intru 70 dion, and at contacts B 5 prepare
the path to operate relay CD over its upper winding when the next
digit is dialled The operation of relay TB at this time is of no
effect The impulses of the next digit enable relay A to respond, con
75 tact Al repeating them over the tie-line, and contacts A 2 enabling
relay CD to operate, which at contact CD 1 provides a low resistance
impulsing loop by short-circuiting rectifier MR 1 80 In the satellite
exchange, upon seizure of the group selector, an earth is applied to
the Pl ead (ICGS), thereby operating relay HF in the incoming
auto-to-auto relay set Relay HF operating, at contacts H Fl and HF 3
short 85 circuit the upper and lower winding respectively of relay
ATA, thereby completing a direct path from the tie-line conductors to
the and + lead ICGS For the rest of the call no change takes place in
the incoming relay set 90 until the call is cleared down The satellite
exchange group and final selectors respond to rne impulses received
over the tie-line, the final selector giving the appropriate tone
indication depending on whether the desired time is idle 95 or busy.
Assuming the satellite exchange subscriber is idle, upon answering,
the final selector (SFS) causes the reversal of the potentials applied
to the tie-line Relay D in the outgoing relay set 10 ( operates to his
condition in series with rectifier MR 2 The operation of relay D, at
contacts Dl operates relay DD, which in turn at contacts DD 4 operates
relay AS over its lower winding by way of contacts TA 5 Relay AS 10 '
operating, although reversing the potentials of the and + leads
(GSMNI) performs no useful function as supervision is not required on
an automatic call between a p a b x subscriber and a satellite
exchange subscriber The 11 ( call is now established and conversation
may proceed.
When the call is terminated, and the p a b x.
subscriber clears, relay A releases and at contacts Al breaks the loop
on the tie-line con 11 ' ductors releasing relay D and also enabling
the final selector in the satellite exchange to release Contact A 2
releasing, short-circuits relay B which releases after a delay Relay D
releasing, at contacts D 1, releases relay DD, 12 ( which at contacts
DD 4 releases relay AS.
With the release of relay D, DD, AS, B and TB the outgoing relay set
is idle once again.
In the satellite exchange the release of the final selector causes the
removal of the earth 12 ' from the P lead ICGS thereby releasing relay
HF which thus restores the incoming relay set to the idle condition
once again.
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* 5.8.23.4; 93p
* GB784679 (A)
Description: GB784679 (A) ? 1957-10-16
Pound board
Date of Application and filing Complete Specification: July 13, 1956.
784,679 No 21709156.
Application made in Switzerland on July 14, 1955.
Complete Specification Published: Oct 16, 1957.
Index at acceptance:-Classes 20 ( 4), V( 10:13); 108 ( 1), B 3; and
113, C 9 g International Classification:-B 62 do B 63 b, E 04 b,
Pound Board W Ae, IMPERIAL CHEMICAI INDUSTRIES LIMITED, a British
Company, of Imperial Chemical House, Millbank, London, S W 1, 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 pound boards.
It has previouslyv been proposed to use pound boards, with
corrugations of substantially trapezoidal shape, as partitions for the
fish-rooms of fishing vessels One fish-room having these pound boards
comprises a number of vertical stanchions disposed at the corners of
squares with about 3-ft sides, each stanchion having vertical channels
for receiving the edged portions of the pound boards The pound boards
when in position serve as vertical partitions and divide the fish-room
into a number of small compartments of square section Each partition
may be formed by several pound boards which are placed one on top of
the other To avoid compressing the lower layers of fish stored in the

small compartments it is desirable to sub-divide the height of the
compartments by using, horizontal panels Hitherto, with the
subdivision it has only been possible to utilise a horizontal panel
between adjacent edges of two pound boards forming part of a
partition, and thus the height can only be sub-divided at a limited
number of positions.
It is an object of this invention to provide a pound board which
enables the height of the small compartments to be sub-divided at more
frequent intervals than hitherto.
According to the invention, we provide a pound board having parallel
longitudinal channels in at least one of its two major surfaces, the
upper edge portion of one wall of each longitudinal channel having a
lT rib directed inwardly of the channel.
The upper edge portion of the other wall of each longitudinal channel
is preferably stepped near its edge, and forms an abutment surface
directed inwardly of the 50 channel If desired the part of the stepped
portion adjacent the edge of the channel may be parallel to the wall
of the channel or inclined at an obtuse angle thereto 55 In a further
embodiment of the invention, a second rib is provided below each of
the ribs referred to in the preceding paragraph but one This second
rib is longer than the first-mentioned rib, is directed 60 inwardly of
the channel and has a shoulder directed away from the base of the
channel This shoulder may be parallel to or inclined away from the
wall of the channel from which the second rib projects 65 If a pound
board has longitudinal channels on only one of its major surfaces it
may be provided with small longitudinal grooves on its other major
surface, each groove having a longitudinal rib on its 70 upper edge
which is directed inwardly of the groove These small grooves are
preferably adjacent the sides of the channels provided with the
inwardly directed ribs.
Figs 1, 2 and 3 of the accompanying 75 drawings show in section three
pound boards in accordance with the embodiments of the invention.
Referring to Fig 1, the pound board 1 has parallel longitudinal
channels 2 on its 80 two major surfaces, the channels on one major
surface alternating with those on the other major surface The upper
edge portion of one wall of each channel is provided with a
longitudinal rib 3 which is 85 directed inwardly of the channel The
edge portion of the other wall of the channel is stepped in the
vicinity of its edge as shown at 4 and 5 Channels formed in this
manner, with ribs and steps enable one or 90 784,679 more brackets 6,
having projecting noses 7 on their upper edge, to be supported by the
pound board since the nose 7 abuts against the rib 3, while the foot S
of the bracket lies on the stepped portion 4 and abuts against the
stepped portion 5 The projecting flange 9 of the bracket 6 can be used

for supporting shelving.
Referring to Fig 2, the pound board 11 o 10 is generally similar to
that shown in Fig.
1, and has longitudinal channels 12, ribs 13 and stepped portions 14 A
second rib lies below each of the ribs 13 and prevents a bracket 16
from tipping The part of the stepped portion 14 adjacent the edge is
inclined at an obtuse angle to the wall of the channel so that the
foot 17 of the bracket cannot slip from its seating.
The height of the bracket-web must, of course, be such that its foot
can be passed over the highest point of the inclined part of the
stepped portion 14.
Referring to Fig 3, a pound board 21 has channels 22 on one only of
its major surfaces Each channel 22 has a rib 23 directed inwardly of
the channel at the upper edge of one of the walls of the channel Under
a rib 23 is a further rib 24 which is longer than the rib 23 and has a
shoulder 25 directed away from the base of the channel A bracket 26
can be mounted between the two ribs 23 and 24.
In order that this type of pound board may support brackets on its
other major surface, recesses are provided in the form of longitudinal
grooves 27, provided with ribs 28 These grooves 27 are preferably
adjacent the walls having the ribs 23 and 24.
A pound board in accordance with the invention has the advantage that
the brackets can be mounted at positions intermediate the ends of the
pound board and it is not necessary to separate the several bhoards
which together form a partition.
When the pound boards form a partition, say in a fish-room, the
brackets on one side of the partition may be positioned at different
heights from the brackets on the other side of the partition.
Since the ribs are at one side only of a channel, care mlust be taken
during the construction of a partition to see that the boards are
correctly mounted, otherwise a bracket might not be supported within
the channel When shelving is required between the ends of a pound
board, it is desirable for the ribs on one pound board to be at the
same height as those of an adjacent pound board so that the brackets
which support a horizontal panel are at the same level However, this
requirement is not critical since'otherwise the shelves will only
acquire a small tilt which corresponds to a half-corrugation This
problem, of course, does not arise with pound boards of the type
described with reference to Fig 3 since the grooves on one major
surface are at the same height as those on the other major surface 70
Pound boards in accordance with the invention may he used i the
construction of walls or partitions which are to support adjustable
shelves, intermediate floors or the like, by means of brackets, and
wlhich 75 are either fixed or movable, such as for example, in fishing

vessels, storerooms, or delivery vans.
When boards of equal length or used for the walls and for the
intermediate shelves, 80 it may often be advantageous to use the
boards in accordance with the invention for the shelves Only a single
type of board is then necessary, which avoids confusion between the
wall-b)oards and special 85 shelving-boards.
The brackets on which the shelvingboards are laid may be extruded
sections, or they may be of sufficient width so as to form the shelves
themselves Various go lengths of bracket are possible, for example,
short brackets or those of length approximately equal to the boards.
Pound boards in accordance with the invention may be conveniently
produced by 95 the extrusion of a light metal, e g, aluminium alloy.
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* GB784680 (A)
Description: GB784680 (A) ? 1957-10-16
New disinfectants and preservatives
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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.
784,680 Date of Application and filing Complete Specification: Aug 7,

1953.
No 21932/53.
Application made in Germany on Aug 7, 1952, Complete Specification
Published: Oct 16, 1957, index at acceptance:-Classes 2 ( 3), C 2 (AI:
A 5: R 15); 49, A 2 (G 2: L), D 1 (G 2: L); and 81 ( 1), E 1 A 3 B( 1:
3).
International Classification:-A Oln A 611 C 07 c.
New Disinfectants and Preservatives We, FARBWERKE HOECHST A Ki
TIENGESELLSCHAFT, vormals Meister Lucius & Br Uining, a body corporate
recognised under German law, of Frankfurt(M)-Hdchst, Germany, 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 new disinfectants and preservatives.
It is known from Specification No 441,120 that amines or ammonium
compounds which contain at least one aliphatically bound hydrocarbon
radical with at least 9 carbon atoms as substituent on the nitrogen
atom, are capable of killing staphylococci, gonococci, and coli and
typhoid bacteria The compounds specified which are preferably used in
the form of their salts have, therefore, proved suitable for
disinfecting and preserving purposes They may, for instance, be
employed for the disinfection of all kinds of table utensils and
storage utensils They are further advantageously used for disinfecting
purposes in medical practice, fur instance for disinfecting medical
instrumnents and the like Laundry, floors, and walls may likewise be
disinfected by means of the compounds specified above Also
foodlstuffs, such as fruits, vegetables, meat, etc may be preserved by
means of the said compounds.
They are further suitable for the preservation of animal material,
such as skins, glands and other organs, etc.
The present invention provides preserving and disinfecting media
comprising a sulphamic acid salt of a fatty amine of the structural
formula R-NH,-O-SO-NIH 2 in which R stands for an aliphatic
hydrocarbon radical with 9-18 C-atoms of which one terminal C-atom is
linked with the Natom elf the NH,-group, said salt being in aqueous
solution The disinfecting and preserving properties of these media are
excellent.
The following fatty amines in the form of lPrice 3 s 6 d l their
sulphamic acid salts may be mentioned by way of example as being
suitable as preserving and disinfecting media: laurylamine,
tridecylamine, myristylamine, pentadecylamine, palmitylamine,
heptadecylamine, stearylamine and oleylamine Advantageously the
sulphamic acid salts may be used of mixtures of amines derived from

fatty acid mixtures such as are obtained by the saponification of the
natural initial material from which these acids are produced, such as
fats or resins, for instance palm oil or coconut oil.
The sulphamic acid salts which are employed according to the present
invention may, :for instance, be prepared as follows: The fatty amine
is dissolved in, alcohol and the equivalent quantity of sulphamic acid
is added, while heating on the steam bath When the dissolution is
complete, the solution is cooled and the sulphamic acid salt of the
amine crystallizes out.
Compared with the compounds of which the disinfectant properties are
already known, the sulpharnmic acid salts according to the present
invention are distinguished, in addition to their excellent general
action, by their capacity for completely kfilling the tubercle
bacilli.
This property could not be foreseen, since neither the sulphamic acid
itself nor other salts of the amines show this effect On account of
this property the compounds specified are advantageously used for
disinfecting purposes, especially for disinfecting medical and dental
instruments As regards their activity towards staphylococci,
gonococci, and coli and typhoid bacteria, the sulphamic acid salts of
amines substantially correspond to the compounds specified in
Specification No 441,120.
In the course of tests made so as to ascertain the activity of the new
disinfecting media towards bacteria, gram positive and gramn negative
bacteria, such as virulent tubercle bacteria, have been subjected in
the usual manner, with variation of the duration of treatment, to the
action of different aqueous concentrations of the disinfecting media
After the termination of this action, the bacteria have been
inoculated on nutrient media under optimum growth promoting conditions
or the sediment obtained by repeated washing in the centrifuge has
been transferred to optimum nutrient media or test animals, (for
instance guinea pigs when tubercle bacilli are concerned) As test
strains may be mentioned:
Staphylococcus aureus SG 511 and some other strains of staphylococci
of the same character, para-typhoid bacteria Breslau and Schottmiller,
typhoid viri, and some strains of coli bacteria As tubercle bacteria
the virulent strain of Tb humanum H 37 Rv, which grows on liquid
Dubos-medium with addition of Staphylococcus SG 511 I Sulphamic acid
salt of the amine of palm seed oil II sulphamic acid salt of the amine
of coconut oil 1: 5,000 and 1:10,000 1: 8,000 and 1:16,000 "Tween 80 "
(Registered Trade Mark), was predominantly employed; in determining
the efficacy, the disinfecting medium was added in a proportion by
volume of 1:4 to the well distributed bacteria contained in a
particular quantity of the Dubos-medium Thus, for instance, 4 cc of

disinfecting medium of a particular concentration were added to 1 cc
of Dubos-medium (incubated for 10 days) and the mixture was intimately
shaken.
The following Table represents the most important results and also
indicates the concentrations in physiological saline cf the
disinfecting media used which killed the bacteria in the techniques
described above.
Bact.
Coli 11 1:10,000 and 1:30,000 1:16,000 and 1:16,000 Bact.
typhi-Vi 1:40,000 1:16,000 and 1:16,000 Tb humanum H 37 Rv 1:1,000
after 15 min.
1:3,000 to 1:5,000 after 45 min.
III sulphamic acid salt of stearylamine IV sulphamic acid salt of the
amrine of mutton tallow V sulphamic acid salt of oleylamine 1: 5,000
and 1: 5,000 1:40,000 and 1:40,000 1:8,000 and 1:16,000 1: 1,000 and
1: 1,000 and 1: 1,000 1: 2,500 1:10,000 and 1:10,000 1:16,000 and
1:16,000 1:1,000 to 1:3,000 after 45 min.
1:10,000 and 1:3,000 to 1:10,000 1:10,000 after 45 min.
1:16,000 to 32,000 and 1:32,000 Apart from the germs indicated above,
the action of the disinfecting media on other microorganisms, such as
protozoons, fungi, yeasts, and viri was tested, which tests in part
likewise showed good results.
Even hard water does not affect the activity of these disinfectants.
We are aware of the Public Health (Preservatives etc in Food)
Regulations, 1925-53, and in so far as our invention relates to the
manufacture for sale in the United Kingdom and/or sale in the United
Kingdom of foodstuffs preserved by the process herein described, we
make no claim to use the invention in contravention of the law.
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* GB784681 (A)
Description: GB784681 (A) ? 1957-10-16

Improvements in and relating to the production of aromatic oxygen-containing
compounds
Improvements in and relating to the Production of Aromatic
Oxygen-Containing Compound
We, We, IMPERIAL CHEMICAL INDUSTRIES LIMITE, a British. Company of
Imperial
Chemical House, Millbank, London, S. W. 1, 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 the production of para-di-acetyl bienzene.
According to the present invention there is provided a process for the
production of para-di-acetyl benzene in which feedstock comprising
para-di-isopropyl benzene is subjected under substantially anhydrous
conditions to oxidation with a gas comprising free oxygen at elevated
temperatures and in which the oxidation is: either conducted directly
in the substantial absence of meta-di-isopropyl benzene to give a
product comprising a substantial amount of para-di-acetyl benzene,
using a catalyst comprising a saltor oxide of a metal selected from
the group consisting of lead, manganese, iron, nickel, cobalt and
copper, at a temperature above 100 C; or the feedstock contains at
least 5% by volume of meta-di-isopropyl benzene and the oxidation is
carried out to give para-di-iso-propyl benzene dihydroperoxide and is
conducted in the presence of two alkaline stabilizing agents, one of
which is a carbonate of an alkali metal or of an alkaline earch metal
or magnesium and the second of which is an alkali metal or an alkaline
earch metal or magnesium salt of a weak organic acid, as hereinafter
defined, at a temperature of up to 125 C., the resulting
paradi-isopropyl benzene dihydroperoxide being separated off and
heated so that it decomposes to give para-di-acetyl benzene as a major

product.
In one mode of carrying out the process of the present invention
para-di-isopropyl benzene is subjected in the liquid phase to the
action of a gas containing free oxygen at a temperature of at least
100 C in the presence of a catalyst comprising a salt or oxide of a
metal selected from the group consisting of lead, manganese, iron,
nickel, cobalt and copper, in order to produce aromatic di-ketones and
other oxygen-containing compounds. In general, the product obtained by
the oxidation of para-di-isopropyl benzene in this way comprises
?,?,?1,?1, tetramethyl para-xylene diol, ?,?, dimethyl para-acetyl
benzyl alcohol, para- di-acetyl benzene, para-acetyl benzoic acid, and
terephthalic acid.
The product may also contain small amounts of compounds in which one
of the isopropyl radicals is unchanged, for example, para-isopropyl
?,?,-dimethyl benzyl alcohol.
The product may also comprise minor quantities of para-di-isopropyl
benzene monohydroperoxide and dihydroperoxide.
The temperature at which the oxidation should be carried out when it
is'desired to produce para-di-aoetyl benzene in appreciable yield
should be 100 to 200 C. Catalysts which it is preferred to use in this
mode of operation are the organic acid salts of the metals disclosed
above, which are soluble in the rection mixture. For example,
toluates, acetates and steatates may be used. It is also possible-to
use the oxides of the metals mentioned. The amount of catalyst may
be varied over a wide range ; for example an amount of 0. 01 toi 51%
of catalyst, based on the weights of metal in combination in the
catalyst and para-di-isopropyl benzene employed, is satisfactory. In
particular, an amount of catalyst of 0.1 to 1% by weight is suitable.
The composition of the final product depends upon the conditions of
operation, and upon the catalyst employed. For example, when operating
at higher temperatures, there will be a greater tendency for acetyl
and carboxylic acid groups to be present in the final product than
when relatively low temperatures are employed. Again, when using
manganous para-toluate as the catalyst, substantially more alcohol is
formed than ketone, whereas when using cupric acetate under comparable
conditions similar quantities of alcohol and ketone are formed.
Finally, a long reaction time favours the formation of acetyl and
carboxylic acid groups, whereas a relatively short reaction time
favours are formation of alcohol groups.
When carrying out the process of the present invention under
conditions such that the final product comprises compounds containing
acetyl, alcohol and carboxylic acid groupings it is advantageous to
operate in the presence of an inert solvent. We have found that
ortho-dichloro-benzene and tetra-chloroethane are particularly

suitable solvents. The presence of a solvent helps to prevent the
occurrence cf side rections, which tend te. result in the production
of a tarry product from which the separation of desired products is
difficult The side reactions also lower the yields of desired
products.
According to another feature cf the present invention, operation is
carried out using a mixture comprising mLta-di-isopropyl benzene and
para-di-isopropyl benzene, these com ;- pounds being converted
initially to their dihydroperoxides. Suitable starting materials for
use in this process are those containing at least 5% by volume of
meta-di-isepropyl benzene; for example the starting material may be a
mixture of 85% by volume paradi-isopropyi benzene and 15% by volume
meta-di-isopropyl benzene.
The oxidation of this mixture of diisopropyi benzenes tc ths
corresponding dihydropercxides is preferably carried out by contacting
: the hydrocarbon with a gas containing free oxygen in the presence
of a peroxide oxidation initiator capabl^ cf initiating a free radical
oxidation chain. A suitable initiator is, for example, a di-isopropyl
benzene di-hydroperoxide which may be fed to the reaction zone from a
previous oxidation rection.
The production of dihydroperoxides from starting materials containing
at least 5% by volume of meta-di-isopropylbenzene, by the process of
the present invention, is preferably carried out at a temperature of
70 to 125 G. Also, this process is carried out in the presence of two
alkaline stabilising agents, one of which is a carbonate of an alkali
metal or an alkaline earth metal or magnesium, and the second of which
is an alkali metal or alkaline earch metal or magnesium salt of a weak
organic acid, as hereinafter defined. For example, the stabilising
agents employed may be sodium carbonate and sodium stearate. In
general, quantities of 0.1 to 2% by weight of stabilising agents,
based on the weight of aromatic hydrocarbon employed, are suitable. In
particular, it is preferable to use of the order of 0.5% by weight of
a salt of a weak organic acid as hereinafter defined, and 1% by weight
of carbonate.
By the term"weak organic acid"is meant an acid which is weaker than
acetic acid, and the alkali m : tal and alkaline earth metal and
magnesium salts of which are at least partially soluble in the initial
reaction mixture employed in the present invention.
The production of dihydroperoxides from starting materials containing
at least 5% by volume of meta-di-isopropylbenzene is facilitated by th
incorporation in the hydrocarbon of 0. 1 to 400 parts per million by
weight of copper or silver, the copper or silver being present
initially as an organic acid salt which is soluble in the rection
mixture. In particular, it is preferable ta use copper stearate,

copper naphthenate or cooper benzoate and for the copper content of
the reaction mixture to be from 1 to 20 parts per million.
It is an essential feature of the present invention that when ! the
first stage of the process is. directed to the production of dihydro-
peroxides, the feedstock comprising meta-di- isopropyl benzene and
para-di-isopropyl benzene, para-di-isopropyl benzene dihydroperoxide
separates. from the rection mixture, and is removed by, for example,
filtration.
The para-di-isopropyl benzene dihydroperoxide is converted to a
product comprising a major amount of para-di-acetyl benzene by
heating, either alone or with an added metal compound. For example,
the conversion may be carried out b. y heating the di-hydroperoxide
with ferrous sulphate. The conversion may also be carried out
thermally by heating the di-hydroperoxide to a temperature above 100
C. A convenient method for converting para-di-isopropyl benzene
dihydroperoxide to a product comprising para-diacetyl benzene is to
heat the di-hydroperoxide with a salt or an oxide of a metal selected
from the group consisting of lead, manganese, iron, nickel, cobalt and
cooper. When the conversion is carried out using a salt, the salt
employed should be one which is incap- able of giving rise under the
rection conditions to a rection mixture having a pH of less than ; 1.
This reaction is preferably carried out at a temperature of up to 200
C.
By using the mode of operation which employs a starting material
comprising a substantial amount of meta-di-isopropyl benzene, economic
advantages may be otained since it is unnecessary to produce a
starting material which is substantially free from meta-di-isopropyl
benzene from, a mixture of di-isopropyl benzenes.
By operating according to the present invention a product containing
para-di-acetyl benzene is obtained. This product is particularly
suitable for further oxidation to tere- plhthalia acid.
When using a mixture of meta and paradi-isopropyl benzenes as the
starting material, the economics of the process can be improved by
recovering meta-di-isopropyul benzene dihydroperoxide from the liquid
remaining after the separation of the para-dihydroperoxide. The
meta-di-isoporpyl benzene dihydroperoxide may be extracted from the
liquid by means of aqueous caustic soda (for example, a solution
containing 10% by weight
NaOH), springing the extract, for example with carbon dioxide, and
filtering. The liquid from which the meta-di-isopropyl benzene
dihydroperoxide has bewen extracted may be returned to the oxidation
stage or may alternatively be purged to thje recovery system.
The meta-di-isopropyl benzene dihydroperoxide can then be converted to
useful products; thus it may be decomposed catalytically, for example

with aqueous sulphuric acid, to resorcinol and acetone.
EXAMPLE 1.
A mixture of 2. 5 litres of para-di-isopropyl benzene and 7. 5 grams
of lead acetate was oxidised for 70 hours at 150 C with air at a gas
rate of 30 litres per hour. The mixture was stirred throughout the
reaction. The crude product was distilled whereby 890 grams of a
distillate boiling below 118 C at a pressure of 1 mm. Hg were
obtained, from which 470 grams of para-di-acetyl benzene separated out
on colling. The yield of paradi-acetyl benzene was 22%.
EXAMPLE 2.
Mixtures of parardi-isopropyi benzene and 0. 075% by weight of
catalyst (based on the weight of cation) were treated with air at a
rate of 30 litres per hour for 315 minutes, the reaction mixtures
being maintained at a temperature of 120 C. The catalysts'present in
the various reaction mixtures were oupric and plumbic acetates and
manganous, ferric and cobaltous para-toluates.
The individual oxidation products were not isolated from the product ;
the contents of alcoholic and ketonic groups were determined by
infra-red methods. The results are given in the Table below.
TABLE
Groups per 100
molecules
Catalyst
Alcoholic Ketonic
Cupric acetate 38 35
Plumbic acetate 58 44
Manganous p-toluate 37 8
Ferric p-toluate 4 25
Cobaltous p-toluate 56 24
EXAMPLE 3.
855 grams of para-di-isopropyl benzene containing 31.5 grams of
anhydrous manganese acetate were heated at a temperature of 150 C in a
reaction vessel through which oxygen was passed at a rate of 100
litres per hour. The reaction mixture was rapidly stirred throughout
the rection. After six thons, 330 litres of oxygen had been reacted
and 890 grams of Hquid and solid products were obtaine.d The liquid
product consisting of 858 grams on analysis was found to contain 64
ketonic groups and 36 alcoholic groups per 100 molecules, indicating
the presence of substantial quantities of para diacetyl benzene.
In addition, the liquid product was extracted with caustic soda
whereby a mixture of sodium salts was obtaine dfrom which 8.3 grams of
terephthalic acid and 167 grams of crude para-acetyl benzoic acid were
isolated.
EXAMPLE 4.

1, 000 grams of starking material comprising 65% by volume para, 32%
by volume meta and 3% by volume ortho di-isopropyi benzene were
mixed with 10 grams of sodium carbonate and 10 grams of sodium
stearate and treated at 80 Cwith40litrespsr hour of oxygen. The
reaction mixture was rapidly strirred throuthout the duration of the
reaction. After 50 horus, the product contained
110 peroxide groups per 100 molecules of product. The reaction mixture
was centrifug and the filter cake washed with fresh starting material
on the centrifuge !. The crude di-hydroperoxide was separated from the
sodium carbonate and sodium stearate by extraction with acetone. After
the removal of the acetone, 280 grams of para-di-isopropyl benzene
dihydroperoxide were obtained.
A solution of one gram of para-di-isopropyl benzene di-hydroperoxide
and 9 grams of para-di-isoporpyl benzene was heated with 1% by weight
of lead acetate, this catalyst concentration being expressed as the
weight of lead per 100 grams of para - di - isopropyl benzene
dihydroperoxide. The reaction was carried out for 3 hours at a
temperature of 150 to 185 C. The product was pale straw in colour and
contained 28% by weight of para-di-acetyl benzene and 45% by weight of
?,?,?1,?1, tetramethyl para-xylene diol.
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* GB784682 (A)
Description: GB784682 (A) ? 1957-10-16
Improvements in or relating to stirrer devices for mixing vessels
A high quality text as facsimile in your desired language may be available
amongst the following family members:

FR1098383 (A)
FR1098383 (A) less
Improvements in or relating to Stirrer Devices for Mixing Vessels
I, ERNST ALFRED REIFFEN, a German
National, of 6, Kirchstrasse, Kassel-Wilhelmshoehe, Germany, do hereby
declare the invention, for which I pray that a patent may be granted
to me, and the method by which it is to be performed, to be
particularly described in and by the following statement:
The present invention concerns stirrers which are used in stationary
mixing vessels and employ as the means for mixing, toothed wheels
whose teeth, when in rotation, pass through the slots of stationary
comb-like bodies disposed free-standing at a distance from each other.
One embodiment of such a mixing device is described, for instance, in
the Specification of British Patent No.
680,309,
According to the present invention a stirring device comprises a
vertically disposed shaft and driving means therefor, a rotary
stirring wheel, having peripheral teeth or blades, mounted on said
shaft, a plurality of radially disposed fixed elements free standing
at a distance from one another, and presenting slots to the stirring
wheel, through which slots the teeth or blades of the stirring wheel
can pass so as to provide a grinding and shearing action, and a
perforate discharge element disposed close to the wheel whereby, in
use, the teeth or blades of the wheel cause a continuous flow of
material being treated in an axial or radial direction through said
discharge element.
The arrangement may be modified and disposed in various manners. There
may be, for example a funnel-shaped container whose lower end is
attached to a lower chamber in which the stirring wheel is disposed.
Either in the bottom or in the upstanding side wall of the lower
chamber, discharge apertures may be provided whose cross-sectional
area is adjustable by means of a shutter. With this controlling
shutter the residence time of the material to be treated within the

chamber can be adjusted as required for the process in hand. The
material to be treated entering the funnel-shaped container on top
must, in its feed motion directed from the top to the bottom, pass the
stirrer- device definitely and at the required rate.
The teeth of the toothed wheel stirrer may be shaped to act
simultaneously as feeding members which feed the material to be
treated in a defined direction whereby the material is continuously
conducted towards and through the stirrer device.
For this purpose, the said teeth can be shaped in one modification
like the blades of a turbine wheel, disposed at an appropriate angle
of incidence. In another modification, the toothed wheel embodies a
double sided impeller whose blades are extended laterally of the wheel
as elongations which pass through the slots of the fixed elements.
The invention will be described further, by way of example, with
reference to the accompanying drawings, in which:
Fig. 1 is a vertical section of a stirrer inserted in a funnel-shaped
container with a chamber at the bottom;
Fig. 2 is a horizontal section on the line II II of Fig. 1;
Fig. 3 is a horizontal section on the line IIIIII of Fig. 1;
Fig. 4 is a vertical fragmentary section of a modified embodiment of
the bottom chamber of the container;
Fig. 4A is a fragmentary perspective view of the toothed wheel;
Fig, 5 is a vertical section showing the disposition of the stirrer
with the object of feeding the material to be treated vertically
within a draught tube;
Fig. 6 is a horizontal section on the line VI-VI of Fig. 5;
Fig. 7 is a vertical section of a modification of the disposition of
the stirrer; and
Fig. 8 is a horizontal section on the line VIIIvm of Fig. 7.
Figs. 1, 2 and 3 show an arrangement wherein a stirrer is disposed in
a funnelshaped container with bottom chamber. A motor 1 drives a
stirrer shaft 3 through a coupling 2. The wheel shaft 3 rotates with
in a tubular casing 4, and at the lower end of this shaft there is
mounted a stirrer wheel 5 with teeth 5'. At the lower end of the
tubular casing 4 are arranged complementary fixed elements 6 which
present slots to the stirrer wheel 5, the teeth 5' of the wheel
passing through these slots. A funnel- shaped container 7 is affixed
to the tubular casing 4 by means of webs 8, and the stirring device
comprising the toothed wheel 5 and the fixed elements 6 is seated in a
chamber 9 attached to container 7, closed with a lid 7'. The chamber 9
ends in a perforated bottom plate 10 which constitutes a perforate
discharge element whose apertures 17 can be more or less closed by
means of a rotary shutter 11. Baffle plates 12 are disposed betveen
the lower part of the tubular casing 4 and the lower part of

funnel-shaped container 7, and the shaft 3 is suspended and guided in
bearings ht 13 and 14, and is sealed with a sealing element 15.
Material to be treated is admitted to the stirrer in the direction of
the arrow 16, through an inlet tube 16'.
In an alternative arrangement of the lower chamber 9, shown in Fig. 4,
the bottom plate 10 has no apertures, and lateral apertures 18 which
can be closed as required by means of an annular shutter 19 are
provided instead in the upstanding side wall of chamber , the side
wall constituting the perforate discharge element in this instance.
Fig. 4A shows a perspective, fragmentary view of the toothed wheel 5
with teeth 5', whose front faces are backed-off or inclined at a
preselected angle to a vertical plane passing through the axis of the
wheel.
The further embodiment of stirrer shown in Figs. 5 and 6 enables the
material to be treated to be fed vertically within a draught tube.
A wheel shaft 20 rotates within a tubular casing 21 and carries at its
lower end, a toothed wheel 22 which includes blade-like teeth 23 the
front faces of which are disposed at a certain angle of incidence to
the vertical. 'The upper and lower edges 24 of the teeth 23 formed
similarly to turbine blades are flattened in the horizontal plane.
The milling faces 24 thus provided, produce within the fixed elements
25, a milling and shearing effect, and a plate 26 disposed close to
the stirrer wheel 22, which plate 26 may be slotted or perforated
constitutes a perforate discharge element of this embodiment
The device is mounted within a draught tube 27 which is suspended in
mixing vessel q5, and when toothed wheel 22 rotates, the material to
be treated is circulated in direction of the arrows from '9 to 30. The
rotary and fixed stirrer elements are sufficiently near each other to
have a milling effect on the material being stirred.
Fig. 7 shows a vertical section through yet another embodiment of the
stirrer, with means whereby a vertical suction of the material to be
treated by the toothed wheel, with a horizontal discharge. is
obtained.
A horizontal section on the line VIII
VIII of Fig. 7 is given in Fig. S.
A wheel shaft 31 rotates within a tubular casing 32 and at its lower
end carries a toothed wheel 33 embodying a double-sided impeller whose
blades 34 are extended laterally of the wheel. and also beyond the
periphery of the wheel as elongations 35 which pass through the slots
of fixed elements 36 disposed around the periphery.
Suction funnels 38 and 3S' are mounted on the tubular casino 32 by
means of collars carried by a number of webs 37. The fixed elements 36
are fixed to a hub 39 which is attached to the tubular casing 32. The
impeller enables the material to be treated to be drawn in

symmetrically on both sides in the direction of the arrows 40-41, and
to be discharged horizontally in the direction of the arrow 42.
Outside the circle of rotation described by the tips of teeth 35,
cylindric- ally bent, either slotted or perforated metal sheets 43 of
channelX e section are arranged between the fixed elements 36. These
sheets constitute a perforate discharge element of the device. The
material to he treated must pass through the apertures of metal sheets
43 when discharged horizontally from the wheel.
In Figs. 7 and 8 there is shown an arranged ment having an open
impeller. In place of such an open impeller, other types of impeller
can, of course, be employed. whose blades likewise extend beyond the
periphery of the impeller disc to form the teeth.
What I claim is:
1. A stirring device for a mixing vessel comprising a vertically
disposed shaft and driving means therefor, a rotary stirring wheel,
having peripheral teeth or blades, mounted on said shaft, a plurality
of radially disposed fixed elements free standing at a distance from
one another and presenting slots to the stirring wheel, through which
slots the teeth or blades of the stirring wheel can pass so as to
provide a grinding and shearing action, and a perforate discharge
element disposed close to the wheel whereby, in use, the teeth or
blades of the wheel cause a continuous flow of material being treated
in an axial or radial direction through said discharge element.
2. A stirring device according to Claim l, wherein a surrounding wall
or casing extends unwardlv from the said fixed elements and die
material to be mixed is fed down

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