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Патент USA US2121760

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June 21, 1938.
E..F. LOWRY ET AL
2,121,760
ELECTRIC DISCHARGE DEVICE
Filed Aug. 29, 1936
F.m/ 2.
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Time
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Ibo
‘INVENTQRS
and
d.
2,121,760
Patented June 21, 1938
UNITED STATES PATENT OFFICE
2,121,760
ELECTRIC DISCHARGE DEVICE
Erwin F. Lowry, Batavia, Ill., and Hymen Dia
mond, Pittsburgh, Pa., assignors to Westing
house Electric & Manufacturing Company, East
Pittsburgh, Pa., a corporation of Pennsylvania
Application August 2-9, 1936, Serial No. 98,470
- 17 Claims.
Our invention relates to electric discharge ap
paratus and it has particular relation to appa
ratus for delaying the initiation and interruption
of current supply to a load.
It is an object of our invention to provide an
accurate time delay relay which shall be simple
and inexpensive.
Another object of our invention is to provide
a time delay relay that shall open and close with
10 a predetermined time delay which may be varied
at will.
'
More speci?cally stated, it is an object of our
invention to provide a system for introducing a
time delay in the application of power to a load
' and the interruption of the supply of power to
the load, the time delay in the former instance
being, at the will of the operator, the same as or
diiferent than the time delay in the second in
stance.
In the practice of our invention, we utilize the
20
time delay involved in the operation of the dis
charge device shown and described in a copen-d»
ing application, Serial No. 43,347, ?led October 3,
1935, Patent No. 2,100,195, dated November 23,
1937, to Erwin F. Lowry, and assigned to the
Westinghouse Electric & Manufacturing Com
pany.
The discharge device in question com
prises an anode and a cathode and a shield en
closing the cathode. The shield operates to de
0 lay the transmission of current between the anode
and the cathode until the cathode is heated to a
predetermined temperature. Accordingly, if an
ode potential and cathode energizing potential
are simultaneously applied to the discharge de
vice, the discharge device is energized a prede
termined interval of time after the application
of potential. At this point, the load to be ener
gized is supplied with current.
When the supply of current is to be inter
rupted, the anode circuit and the heating circuit
for the cathode of the discharge device are simul
taneously interrupted. 1The supply of current
through the discharge device is interrupted and
In accordance with
our invention, we provide a second discharge de
vice connected in parallel with the ?rst discharge
_ ‘the cathode begins to cool.
50
device, which, when the anode circuit of the ?rst
discharge device is opened, becomes energized
and continues the supply of current to the load.
' The control circuit of the second discharge device
is connected to the shield circuit of the ?rst
discharge device, and as the cathode of the ?rst
discharge device cools, a control potential is sup
55. plied to the second discharge device, which, after
(Cl. 250—2’7)
a predetermined interval of time, causes the sec
ond discharge device to become deenergized.
To avoid super?uous verbiage in the claims, we '
shall here de?ne the discharge device which is
disclosed in the above~mentioned Lowry applica
CI
tion as a shield-cathode discharge device or a dis
charge device of the shield-cathode type. Ac
cordingly, a shield-cathode discharge device for
the purpose of this application is a discharge de
vice having at least one emissive cathode, an elec
trode cooperating therewith as a charge-collect
ing electrode, and a shield enclosing the cathode,
which, when heated, emits electrons to the oath
ode. In practice, a suitable circuit is connected
between the shield and the cathode of a shield 15
cathode discharge device which provides for the
application of a blocking potential to the shield
as long as the cathode and the shield are cold.
However, when the shield becomes heated by rea
son of heat radiation from the cathode, the eifect N O
of the blocking potential is neutralized and a dis
charge passes between the collecting electrode
and the cathode of the discharge device. It is
apparent, of course, that the discharge device of
the shield-cathode type may be asymmetric in 9
structure, and accordingly may have a non-emis
sive electrode and an emissive cathode. It may
also, however, be symmetric in structure and have
two emissive electrodes, each of which is provided
with a shield. The term “shield cathode dis- 3
charge device”, or its equivalent, is used herein
with the understanding that it encompasses any
device in which the speci?c features of the Lowry
discharge device are involved.
The novel features that we consider charac- ‘
teristic of our invention are set forth with par
ticularity in the appended claims. The inven-'
tion itself, however, both as to its organization
and its method of operation, together with addi
tional objects and advantages thereof, will best 40
be understood from the following description of
a speci?c embodiment when read in connection
with the accompanying drawing, in which:
Figure l is a diagrammatic view showing a
preferred embodiment of our invention; and
45
Fig. 2 is a graph illustrating the operation of
our invention.
The apparatus shown in Fig. 1 comprises a dis
charge device I of the shield-cathode type hav
ing an anode 3, an emissive cathode 5, and. a
shield ‘l enclosing the cathode, as is explained in
the above-mentioned co~pending Lowry applica
tion. The electrodes 3, 5 and ‘I are enclosed in
a gas-tight envelope 9 in the usual manner. In
the envelope 9 an ionizable medium, such as a 56
2
2,121,7c0
noble gas or the vapor of a globule of a metal
such as mercury, is present.
Anode potential is supplied to the discharge
device I by a secondary section II of a supply
transformer I3, and cathode heating current is
supplied by another secondary section I5 of the
transformer. A double-pole switch I1 is provided
for simultaneously closing the anode and cathode
circuits.
When this switch is operated to close
10 the circuits, the temperature of the cathode COll'l
mences to rise.
However, a discharge does not
take place in the discharge device I by reason of
the fact that the shield 1 is connected through a
variable resistor IE! to the negative terminal of
a battery 2|, the positive terminal of which is
connected to the cathode 5.
As is explained in the Lowry application, the
shield 1 is capable of electron emission, and as it
is heated by the radiation from the cathode 5,
20 electrons pass from the shield to the cathode
under the action of the battery 2|. A potential
drop tending to neutralize the effect of the source
2|. is, therefore, produced across the resistor I9,
and this drop continues to increase as the tem
perature of the shield 1 increases until the effect
of the battery is totally overcome and the dis
charge device passes current. The exciting coil
23. of a relay 25 in circuit with the discharge de
vice I is energized when the discharge device I
passes current. When the relay 25 is thus encr
gized, its .upper movable contactor 21 closes a
work circuit 29 to perform whatever function is
to be performed.
The time delay involved in the operation of the
relay is determined by the magnitude of resistor
I9 in circuit with the shield ‘I. This is illustrated
in the graph shown in Fig. 2. In this graph, the
difference of potential between the shield and
the cathode is. plotted as ordinate and the time
40. in seconds which elapses between the closing of
the double-pole switch I1 and the excitation of
the discharge device I is plotted as abscissa for
different resistors in the shield circuit. The
family of full line curves 3|, each of which cor
responds to a resistance I9 of different mag~
nitude, illustrates how the negative difference of
potential varies as a function of time. In each
case, the absolute value of the potential between
the shield 1 and the cathode 5 decreases as the
time of heating the shield increases until a point
33 is attained, at which the discharge device com
mences to pass current. We have found that the
greater the magnitude of the resistor IS, the
longer is the interval of time between the closing
55 of the switch I1 and the excitation of the dis
charge device I. By adjusting the resistor I9 to
a proper magnitude, the delay in ‘the operation
of the relay 25 following the operation of the
double-pole switch I1 may be predetermined at
60 will. While we have illustrated the resistor I9
as having a movable top, this showing should be
regarded merely as symbolical, since, under cer
tain circumstances, it may be desirable to utilize
a plurality of independent resistors and a mov
able contactor for selecting one of them, as is
illustrated, for example, in Fig. 5 of the copend
ing Lowry application.
When the double-pole switch I1 is opened, the
anode circuit and the cathode heating circuit are
,_ simultaneously disconnected from their respec~=
tive secondary supply sections II and I5.
The
cathode 5 and the shield 1 now begin to cool and
the negative potential difference between the
shield and the cathode now rises.
The rise of
7.5 the potential difference for any given resistor
iii in the shield circuit corresponds to the de
crease in the potential diiference for the same
resistor. A single broken line curve 35 is plotted
to illustrate the cooling situation in one case. It
is understood, of course, that there is a family of
curves 35 just as there is a family of curves 33.
From the above observations, it will be seen that
by selecting a proper magnitude for a resistor
such as IE3 in series with the shield 1, the cooling
of the shield and, therefore, the time required for 10
the potential between the shield and the cathode
5 to become equal to the potential of the battery
2% may be predetermined. If the latter time in
terval is to be different than the time interval in
volved in the excitation of discharge device I, lo
a different shield circuit, including a resistor 31
different magnitude than the resistor is, may
be provided. The shield circuit, including the re
sistor 31, is closed by a movable contactor 39 of
the relay 25 when the relay is energized, and at 20
the same time a movable contactor 4i , which had
maintained the shield circuit including resistor
I9 closed, opens the latter circuit. In the embodi
ment illustrated, the resistance 31 is smaller than
the resistance I9, and accordingly the time delay
involved in the opening or" ‘the work circuit 29
is smaller than the time delay involved in its
closing.
It will be noted that in the description of the
system thus far we have only shown that a time 30
delay
involved in the deenergization of dis~
charge device I. However, the time delay involved
in the cooling of shield 1 cannot be directly used
to control relay 25, since both the anode circuit
and the cathode heating circuit of the discharge
device i are opened simultaneously. The cathode
heating circuit, must of course, be opened to en
able the cathode to cool and time the opening op
eration of the tystem. The anode circuit must be
opened, because unless it is opened, a discharge 40
will persist in the discharge device I and the
cathode 5 will be maintained heated by the dis
charge current in spite of the fact that its own
heating circuit is open.
Accordingly, to maintain the relay 25 en
ergized while the shield 1 is cooling, we provide a
second discharge device 43 having an anode 45,
a cathode 41, and a control electrode 49.
The
second discharge device 43 is not energized be
iore the ?rst discharge device I is energized, and .
for this reason, its cathode heating circuit may
be maintained open until the ?rst discharge de
vice I is energized. To accomplish this purpose,
the heating circuit for the cathode 41 is normally
open and the relay 25 is provided with a fourth
movable contactor 5|, which, when the relay 25
is energized following the energization of dis
charge device I, closes the heating circuit.
The cathode 41 is supplied with heating cur
rent from a secondary section 53 of the trans 60
former I3. The anode 45 is connected to the
upper terminal of the secondary section II,
whereby the anode potential is supplied to the
discharge device I, through the exciting coil 23
of the relay 25 and it is accordingly connected
to the anode 3 of the discharge device I when the
double~pole switch I1 is closed. The cathode 41
of the discharge device 43 is connected to the
cathode 5 of the discharge device I. Hence,
when the discharge device I is energized and the 70.
excitation of the cathode 41 of the discharge de
vice 43 is completed, the discharge device 43 does
not become energized since the potential drop
between its anode 45 and its cathode 41 is the
same as the potential drop between the anode 3 M
3
2,121,760
and cathode 5 of the discharge device I, and this
is too small to produce a discharge in the dis
charge device 43 as long as the former device re~
mains energized. If necessary, a biasing source
55 may be connected to the control electrode 49
10
15
20
25
of the discharge device 43, and to make certain
that the latter remains deenergized, discharge
device I is energized.
When the discharge device I is deenergized by
the opening of the double-pole switch II, the po
tential drop across the anode~cathode circuit of
this discharge device becomes equal to the poten
tial drop across the secondary section II of the
transformer I3. The biasing potential 55 sup
plied to the control electrode 49 is then no longer
su?icient to maintain the discharge device 43 de
energized and it is immediately energized. The
relay 25 may be provided with a lag loop 51 to
prevent its becoming deenergized in the short in
terval of time between the deenergization of the
discharge device I and the energization of the
second discharge device 43. The relay 25 is, there
fore, maintained energized after the discharge
device I is deenergized by the current ?owing
through the second discharge device 43.
The control electrode 49 of the discharge device 43 is connected through the biasing poten
tial 55 to the shield 'I of the discharge device I,
and, therefore, the control circuit of the dis
charge device 43 includes the movable contactor
39 of there1ay25, the resistor 31, and the battery 2|
associated with the shield ‘I of the ?rst discharge
device I. As the cathode 5 and the shield ‘I of the
discharge device I now cool, the potential drop
means being more effective in causing a current
to ?ow in said ?rst path than in said second
path, whereby a current ?ows in said ?rst path
before it ?ows in said second path, means coop
.erative with said ?rst path for preventing current
from flowing in said second path when current
?ows'in said ?rst path, and means for causing
current to flow in said second path as a result
of the interruption of current flow in said ?rst
path.
10
2. In combination, a ?rst current path, means
for causing a current to ?ow in said ?rst current
path an interval of time predeterminable at will
after the occurrence of an operation, a second
current path, means tending to cause a current 15
to flow in said second path, means for rendering
the last-said means ineffective before a current
flows in said ?rst current path, means coopera~
tive with said ?rst current path for rendering
said current-?ow-causing means ineffective while 20
a current ?ows in said ?rst path, and means for
rendering said current-flow-causing means effec
tive, on the interruption of a current in said ?rst
path, to cause a current to ?ow in said second
path.
25
3. In combination, a ?rst current path, means
for causing a current to flow in said ?rst cur
rent path an interval of time predeterminable at
will after the occurrence of an operation, a sec
ond current path, means tending to cause a cur
electrode 49 of second discharge device 43 de
30'
rent to flow in said second path, means for ren
dering the last-said means ineffective before a
current flows in said ?rst current path, means
cooperative with said ?rst current path for ren
dering said current-flow-causing means ineffec 35
tive while a current ?ows in said ?rst path, means
creases, and, therefore, the negative potential
for rendering said current-fiow-causing means
difference between the control electrode 49 and
the cathode 4'? increases. This varying condition
40 persists until the potential between the control
electrode 49 and the cathode 41 becomes suf
?ciently negative to deenergize the second dis
charge device causing the relay 25 to be deener
gized and the work circuit 29 to open.
Our invention has been shown and described
hereinabove as embodied in a speci?c system.
Many of the features of this system are to be
taken as symbolical. For example, in practice, it
may often happen that other elements than a
50 double-pole switch are utilized to simultaneously
close the anode and the cathode circuits of the
shield-cathode discharge device I. In particu
effective, on the interruption of a current in said
?rst path, to cause a current to ?ow in said sec~
across the resistor 31 in circuit with the control
lar, a photo-cell circuit or an inductance or ca
pacity responsive circuit may replace the switch
I‘I. Hence, the double-pole switch I‘! is to be
taken as symbolical of a general control element.
In the embodiment described hereinabove, and,
in general, preferably, discharge devices I and 43
of the gas or vapor-?lled type are utilized. It will
60 be apparent, however, that our invention may be
practiced with discharge devices of the high vac
uum type, and, therefore, systems in which higl'i
vacuum discharge devices are utilized in lieu of
the gas-?lled devices described in the preferred
embodiment lie within the scope of our invention.
Although we have shown and described certain
speci?c embodiments of our invention, we are
fully aware that many modi?cations thereof are
possible. Our invention, therefore, is not to be
restricted except insofar as is necessitated by the
prior art and by the spirit of the appended claims.
We claim as our invention:
1. In combination, a ?rst current path, a sec
ond current path, means tending to cause a cur
rent to ?ow in said current paths, the last said
ond path, and means for interrupting the current .
?ow in said second path after an interval of time
predeterminable at will.
4. In combination, a ?rst current path, means
for restraining current from ?owing in said first
path, a second current path, means for restrain
ing a current from flowing in said second path for
an interval of time predeterminable at will after
an operation and thereafter causing a current to
flow in said second path, the last means func
tioning to render said ?rst~mentioned restrain
ing means ineffective when a current is permit
ted to flow in said second path, means coopera
tive with said second path for restraining a cur
rent from ?owing in said ?rst path while a cur
rent ?ows in said second path and means for
interrupting current flow in said second path
whereby current ?ows in said ?rst path.
45
'50
55
5. In combination, a ?rst current path, a sec
ond current path, means for restraining current
from ?owing in said paths for an interval of
time predeterminable at will after an operation
and thereafter permitting current to ?ow in said
paths, current being permitted to flow in said
?rst path before it is permitted to flow in said
second path, and means cooperative with said
?rst path for restraining current from flowing 65
in said second path while current flows in said
?rst path, whereby when the current is inter~
rupted in said ?rst path current is permitted to
?ow in said second path.
6. In combination, a first current path, a sec
70
ond current path, means for controlling the flow
of current in said paths, said controlling means
when actuated in one sense operating to restrain
current from ?owing in said paths for an inter
75
4
2,121,760
val of time predeterminable at will after the last
said actuation and thereafter permitting cur
rent to flow and when actuated in the opposite
sense after having been actuated in. the ?rst
sense operating to permit current to ?ow in said
paths for an interval of time predeterminable
at will after the last said. actuation and there
after restraining current from ?owing, means
associated with said second path for restraining
charge is interrupted in said ?rst path.
10. In combination, a ?rst dischage path hav
current from ?owing in said second path, on the
at will after the said operation and thereafter '
actuation of said controlling means in the ?rst
sense, until after current ?ows in said ?rst path,
and means cooperative with said ?rst path for
restraining current from ?owing in said second
path while current is ?owing in said ?rst path.
permitting a discharge, and when operated in the
'7. In combination, a ?rst current path, a sec~
0nd current path, means for controlling the ?ow
of current in said paths, said controlling means
when actuated in one sense operating to restrain
current from ?owing in said paths for an inter
val of time predeterminable at will after the last
said actuation and thereafter permitting current
to flow and when actuated in the opposite sense
after having beenactuated in the ?rst sense oper~
ating to permit current to ?ow in said paths for
an interval of time predeterminable at will after
the last said actuation and thereafter restraining
current from ?owing, means associated with said
second path for restraining current from ?ow
ing in said second path, on the actuation of said
controlling means in the ?rst sense, until after
current ?ows in said ?rst path, means coopera
tive with said ?rst path for restraining current
from ?owing in said second path while current
is flowing in said ?rst path, and means for in~
terrupting current ?ow in said ?rst path while
said controlling means is actuated in said oppo“
site sense whereby current ?ows in said second
path for an interval of time predeterminable at
40 will and is thereafter interrupted.
8. In combination, a ?rst current path, a sec~
0nd current path, means for controlling the ?ow
of current in said paths to restrain and permit
current to ?ow therein, means associated with
said second path to restrain current from ?owing
in said second path when said controlling means
has been actuated to permit current to ?ow in
said paths, until after current has been permitted
to flow in said ?rst path, means cooperative with
said ?rst path to restrain current from ?owing
in said second path while current ?ows in said
?rst path, and means for actuating said control
ling means in one sense to restrain current from
flowing in said ?rst path for only an interval of
56 time predeterminable at will after the said actu
ation and thereafter to permit current to flow
in said paths, whereby current ?ows in said ?rst
path, and for actuating said controlling means in
the opposite sense to interrupt current ?ow in
60 said ?rst path and to permit current to flow in
said paths for an interval of time predeterminable
at will alter the last said actuation and there
after to restrain current ?ow in, said paths, where~
by current ?ows in said second path for said last65 mentioned interval of time.
9. In combination, a ?rst discharge path hav—
ing a control electrode, controlling means when
operated in one sense, cooperative with said con
trol electrode for restraining a. discharge in said
70 ?rst path for an interval of time predeterminable
at will after said operation and thereafter per“
mitting a discharge and when operated in the
opposite sense for permitting a discharge for an
interval of time predeterminable at will af ter the
76 last said operation and thereafter restraining it,
a second discharge path, and means cooperative
with said ?rst discharge path for restraining a
discharge in said second path until after a dis
ing a control electrode, controlling means when
operated in one sense cooperative with said con
trol electrode for restraining a discharge in said
?rst path for an interval of time predeterminable
opposite sense for permitting a discharge for a
predetermined interval of time and thereafter
restraining it, a second discharge path, means
cooperative with said ?rst discharge path for
restraining a discharge in said second path until
after a discharge is interrupted in said ?rst path,
and means including said controlling means for
interrupting the discharge in said second path
after said last-mentioned predeterminable inter- L!
val of time on the operation of said controlling
means in said opposite sense.
11. In combination, an electric discharge de
vice of the shield cathode type, means for im
pressing a principal potential on said discharge
device, means for impressing a potential between
the shield and the cathode of said discharge de
vice, means ior energizing the cathode of said
ischarge device, another discharge device hav~
ing a plurality of principal electrodes and a con- '
trol electrode, means for connecting the principal
electrodes of said last-mentioned discharge de
vice in parallel with the principal electrodes of
said ?rst-mentioned discharge device, and means
for initiating a discharge in said last-mentioned
discharge device as a result of the interruption
only of a discharge in said ?rst~mcntioned dis
charge device.
12. In combination, an electric discharge de
vice of the shield cathode type, means for im 40
pressing a principal potential on said discharge
device, means for impressing a potential between
the shield and the cathodes of said discharge
device, means for energizing the cathode of said
discharge device, another discharge device hav~
ing a plurality of principal electrodes, and a con~
trol electrode, means for connecting the principal
electrodes of said last—mentioned discharge de
vice in parallel with the principal electrodes of
said ?rst-mentioned discharge device, means for
initiating a discharge in said last-mentioned dis
charge device as a result of the interruption only
of a discharge in said ?rst-mentioned discharge
device, and means for connecting said control
electrode to said shield, whereby the discharge ,
in said last-mentioned device persists after the
interruption of a discharge in said ?rst-men
tioned device for an interval of time correspond
ing to the circuit of said shield.
13. In combination, an electric discharge de~
vice of the shield cathode ‘type, means in circuit
with the shield and the cathode of said dis
charge device for supplying a potential between
the shield and the cathode, a source for supply
ing principal potential to said discharge device,
a source for supplying energy to said cathode,
means for simultaneously connecting and dis
connecting said potential-supply source and said
energy supply source to said discharge device,
another discharge device having principal elec
trodes and a control electrode, means for con
necting the principal electrodes of said last
named discharge device in parallel with the prin~
cipal electrodes of said ?rst-named discharge
device, means functioning to energize said last 75
5
2,121,760
named discharge device as a result only of the
interruption of a discharge in said ?rst-named
device, a circuit for the control electrode of said
last-named discharge device, and means for so
connecting said circuit to the shield circuit of
said ?rst-named discharge device that current
initiated in said last-named device persists only
for an interval of time predetermined by the
shield circuit of said ?rst-named device.
10
14. Apparatus according to claim 13 charac
terized by means to be actuated when the ?rst
narned discharge device is energized for changing
the constants of the shield circuit of said dis
charge device.
15
15. In combination, a ?rst dischargedevice,
said discharge device having an anode, a cathode
and a control electrode, a source for supplying
potential between the anode and the cathode
of said ?rst discharge device connected to said
discharge device, a source for supplying energy
to the cathode of said discharge device, a circuit
for the control electrode of said discharge device,
a second discharge device, said second discharge
device being of the shield cathode type, a source
25 for energizing the cathode of said second dis
charge device, means for simultaneously connect
ing and disconnecting said energizing source and
said cathode and the principal electrodes of said
second device in parallel with the principal elec
30 trodes of said ?rst device, a circuit for the shield
of said second deviceproviding for excitation of
said second device a predetermined interval of
time after said connecting and disconnecting
means is operated to connect said ?rst device,
means to be actuated in response to the excita
tion of said second device for connecting the
energizing source to the cathode of the ?rst de
vice, and means for so connecting the control
circuit of the ?rst device and the shield circuit
of the second device that the ?rst device is ener
gized as a result of the interruption of a dis 10
charge in the second device and remains ener
gized for an interval of time predetermined by
the shield circuit of the second device.
16. In combination, an electric discharge de
vice having a control electrode and a plurality
of principal electrodes, an electric discharge de
vice of the shield cathode type, a shield circuit
for the last-named discharge device and means
cooperative with said shield circuit for impress
ing a potential between the control electrode and 20
a principal electrode of said ?rst-named discharge
device.
'
1'7. In combination, an electric discharge de
vice having a plurality of principal electrodes,
a shield-cathode discharge device and means 25
cooperative with the shield of said last-named
discharge device for controlling the discharge
between the principal electrodes of said ?rst
named discharge device.
'ERWIN F. LOWRY.
HYMEN DIAMOND.
30
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