Патент USA US2503735

Aprll 11, 1950
2,
K. w. HESS
‘
PROTECTING DEVICE FOR
GAS 0R v APOR-FILLED,
' CONTROLLED DISCHARGE TUBES
Filed Feb. 12, 1949
4
vvvvvvvv
KARL VIMLTER HESS.
_
INVENTOR.
sv?
AGENZ
2,503,735
Patented Apr. 11, 1950
UNITED STATES PATENT OFFlCE
2,503,735
rRoTEo'rING DEVICE FOR GA-S- v0R VAPOR’
FILLED CONTROLLED DISCHARGE TUBES
Karl Walter Hess, Eindhoven, Netherlands, as
signor to Hartford National Bank and Trust
Company, Hartford, Conn., as trustee
Application February 12, 1919, Serial NIo."_7G,145
In the Netherlands March 13, 1948
7 Claims. (01. 315-291)
1
2
This invention relates to a protecting device for
gas- or vapour-?lled, controlled discharge tubes
which are cut oil‘ by the control means inthe
case of excessively high currents and back?res
in the tube, and is characterized in that, in order
In'ithe event of defects in the ‘second high
vacuum-tube (11), due to which it cannot be
made conductive by the first ‘high-vacuum tube
to provide additional protection against defects
of the protecting device, the latter comprises,
signalling device.
at least two controlled high-vacuum tubes which
are included in the control-circuit of the dis
II) are preferably combined to form a. single
charge tube in such arrangement that, in a nor
arate control-members, but a common cathode
mal conductive state of one high-vacuum tube
(I), the discharge tube is allowed to operate by
and ?lament. Since defects ‘in high-vacuum
tubes practically always originate from the oath
the control-voltage, whereas in the case of ex
ode and the ?lament, both of the high-Vacuum
(I), “swinging” may be made perceptible by a
signally device.
1
'
However, the two high-vacuum tubes (I and
high-vacuum tube having separate anodes, sep
tubes are then out of action, so that the dis
15 charge tube is also cut off.
In order that the invention may be more
vacuum tube (I) is given a pulse by which this
clearly understood and readily carried ‘into ef
tube is cut off, or at least the anode current is
fect, it will now be described more fully with
limited to a lower value, this anode current limi
cessively high currents and back?ring in the dis
charge tube, the control-member of the high
reference to the accompanying drawing, given
tation resulting not only in the supply of a cut
off voltage to the discharge tube by way of its 20 by way of example, in which 'a few embodiments
of the invention are represented diagrammati- .
controlémember but also in making the other
cally.
high-vacuum tube (II) conductive in such man
Referring to Fig. 1, the reference numeral l
ner that the cut-01f voltage ‘across the discharge
designates a gas- or vapour-?lled discharge tube
tube is maintained.
I
Since use is made of ‘a high~vacuum tube which 25 which is included in a recti?er circuit and is
controllable by means of a grid 2. _The anode
only in its normal conductive state allows op
lead comprises a current transformer 3 of
eration of the discharge tube which may be in
which the secondary winding 4 transmits pulses,
cluded in a recti?er circuit, the advantage is se
through a resistance 5 and a condenser 6, to a
cured that in the case of failure of the high
vacuum tube, due to which this tube is put out 30 grid '1 of a ?rst high-vacuum tube 8_ in the event
of currents exceeding the normal anode current
of action, the discharge tube also is cut off.
of the discharge tube 1.
_
In the event of excessively high currents or
In the event of back?re in the discharge tube
back-?ring in the discharge tube a pulse is trans
I, the resistance 5, the condenser 6 and the grid
mitted to the operative high-vacuum tube (I)
with the result that it is put out of action or 35 7 likewise receive pulses through a condenser 9
connected to the anode-lead, the resistance 5
carries a lower anode current such that also in
and a condenser Ill and back to the cathode of
this event the discharge tube is cut off. Since
the discharge tube l.
.
_
the said pulse is only of short duration, the high
During normal operation the discharge tube
vacuum tube and consequently, also the dis
I is periodically made operative by a suitable al
charge tube, would again become operative upon
ternating control-voltage from a control-trans
termination of the pulse. As long as the defect
former II through a resistance I2, since the
in the latter is not remedied. the cycle is re
source [3 of negative cut-off voltage is ade
peated. In order to avoid this, the second high
quately compensated by the voltage drop across
vacuum'tube (II) is made conductive upon anode
current limitation or complete cutting off of the 45 the anode resistance I4 of the high-vacuum tube
8 which is conductive during normal operation
high-vacuum tube (I), with the result that the
and of which the source of anode voltage is des
cut-off voltage across the discharge tube is main
ignated l5. Through resistance l6 and anode
tained. This may, for example, be effected by
resistance I‘! of a second high-vacuum tube l8
providing that the second high-vacuum tube
produces a cut-off voltage across the discharge 50 and through the source ll‘) of anode voltage, this
high-vacuum tube has such a grid voltage that
tube, by which voltage this tube is maintained
it is conductive, and in this event the tube 18
cut-off,_even when the ?rst high-vacuum tube
may also be conductive to a certain degree. The
(I) again becomes normally operative upon ter
tube [8 is connected with its grid l9 to the an
mination of the interference pulse; thus avoid
ing “swinging.”
55
ode of tube 8.
_
-
-'
£2,503,735
If, in the event of excessively high currents or
of back?res occurring in the discharge tube I,
the high-vacuum tube 8 is cut off or its anode
current is adequately reduced, the compensat
ing voltage drop across the anode resistance I4
decreases" to, such adegree that, owing tothe
then predominating negative grid voltage of the
supply I 3, the ignition voltage across the re
sistance I2 cannot become suf?ciently positive to
ignite the discharge tube I. Consequently, this
tube is then cut oil‘. However, upon termina
tion of the interference pulse across transformer
4.
that the tube is not cut-oil“, whereas the tube is
cut oif in the event of an excessively high cur
rent which, consequently, considerably exceeds
the normal current.
As stated, back?ring is avoided by providing
a condenser .9 which is connected in such man
her that a ‘negative pulse 'is applied to the grid
in the event of'back?re occurring in the dis
charge tube. In the case referred to the nega
tive pulse is already produced at a voltage vari
ation of sui?cient speed and value, so that cut
ting o? ‘of the discharge tube is initiated even
before back?ring occurs.
3, the high-vacuum tube 8 would again ignite,
thus enabling also ignition of the discharge tube
In the diagrams described the reliability of
I. To avoid this at least temporarily, the grid 15 the protecting device practically entirely depends
IQ of the second high-vacuum tube I8‘ is conupon freedom from interference of the source I3
nected to the anode of tube 8 (or to a suitable '
of negative grid voltage. However, with the use,
tapping of the anode resistance I4) owing to
for example, of accumulator batteries its oper
which the aforesaid decrease in voltage drop
ation may be made steady so that disturbances
across the anode resistance I4 and the consequent
are practically excluded. Additional protection
increase in positive'potenti'al" of‘ the anode of
may be provided by using the voltage of supply
tube 8, results in that the grid of tube; I8 be
I3 as a control-voltage for a main switch by
comes positive to such a'degree that-this tube
which the primary of the supply transformer for
either becomes conductive, from the non-con
the discharge tube I is switched off when the
ductive state, or transmits a higher anode cur 25 voltage of I3 becomes too low.
rent than before. Consequently, the anode volt
What I claim is:
age of tube I8 drops to such a degree that the
voltage across resistance I8 and hence across
,
grid ‘I decreases su?'iciently 'to prevent tube v8
from conveying the normal current which
would be required to ignite again the discharge
tube I. As long as the tube I8 carries the high
anode current, tube 8 consequently conveys a re
1. In a rectifying circuit-arrangement provid
ed with a gaseous discharge device having a cath
ode, an ignition electrode and a plate, said de
vice being interposed in an alternating-current
circuit to effect recti?cation, and means to ap
ply an alternating voltage to said ignition elec
trode periodically to ignite said device, a pro
duced current or no current at all.
i
tective system preventing excessive current flow
When tube 8 is made inoperative due to a de 35 and back?re in said device comprising ?rst and
fect, the compensating voltage across the anode
second electron discharge tubes each having a
resistance I4 likewise disappears and the dis~
cathode, a grid and an anode, ?rst and second
charge tube I is cut off by I3 or caused to ‘pass
resistances connected respectively to the anodes
a permissible low current. This may be effect
of said ?rst and second tubes, means coupled to
ed by means of circuit-arrangements known per 40 said alternating-current circuit to derive con
se, for this purpose.
trol pulses therefrom having an intensity depend
Fig. 2 represents a circuit-arrangement, in
ing on the current ?ow through said device,
which the-anode resistance I‘I shown in Fig. 1
means to apply said control pulses to the grid
is likewise included in the grid-circuit of dis
of said ?rst tube to render said tube non-con
charge tube I. This results in that, in the afore 45 ductive when the current ?ow in said device ex
said event‘of an increase in anode current in
ceeds a predetermined safety value thereby to
tube I8 owing to an interference pulse at the
develop a control potential across said ?rst re
grid of tube 8, the voltage drop across resistance
sistance, means to apply said control potential
I1 is increased, so that the negative grid bias
to said ignition electrode in a direction extin
of discharge I is likewise increased. The polar
guishing said device, means to apply said con
ity of the voltage across resistance I1 is, in ef
trol potential to the grid of said second tube in
fect, such that the negative voltage of I3 is sup
a direction increasing the conductivity of said
ported. This yields more security in preventing
second tube thereby developing a biasing poten
the discharge tube I from becoming again op
tial across said second resistance, and means to
erative.
.
55 apply said biasing potential to the grid of said
According to the invention, a practical guaran
?rst tube to maintain same non-conductive.
2. In a rectifying circuit-arrangement provid
tee against breakdown of the protecting device
ed with a gaseous discharge device having a
itself, without the use of the aforesaid signalling
cathode, an ignition electrode and a plate, said
device, is obtained by- combining the two high
vacuum tubes 8 and I8 to form a single tube 60 device being interposed in an alternating-cur
rent circuit to effect recti?cation, and means to
having separate anodes and control-members,
apply- an alternating voltage to said ignition
but a common cathode. This is shown in Fig. 3.
electrode periodically to ignite said device, a
In this case'a defect in tube 20, which practi
protective system preventing excessive current
cally always originates from the cathode and
the ?lament, results in that neither of the anodes 65 ?ow and back?re in said ‘device comprising ?rst
and second electron discharge tubes each hav~
conveys current, so that the compensation volt
ing a cathode, a grid and an anode, ?rst and
tage acrossthe resistances Ill and I1 respec
tively fails and the cut-off voltage I3 predomie
second resistances, means to apply an anode po
tential through said ?rst and second resistances
The arrangement'of the secondary winding 4 70 to the anodes of said ?rst and second tubes re
spectively, a cut-o? bias voltage soru~ce connect
of the transformer 3 is chosen to be such that
ed between the ignition electrode and the oath
at least at the beginning of each current period
during normal operation of the discharge tube I,
ode of said device through said ?rst resistance,
said ?rst resistance havinga value at which the
a pulse is transmitted to the grid ‘I oftube 8, the
intensity of the pulse being chosen to be such 75 voltage drop developed thereacross'during the
nates.
~
I
~
2,503,735
5
conduction of said ?rst tube has a magnitude
counteracting the cut-off bias on said device,
means coupled to said alternating-current cir
6
?rst tube to the grid of said second tube whereby
the voltage developed at the anode of said ?rst
tube during the non-conduction thereof increases
the conductivity of said second tube, means con
cuit to derive control pulses therefrom having
necting the anode of said second tube to the grid
an intensity depending on the current ?ow
of said ?rst tube whereby the potential developed
through said device, means to apply said con
at the anode of said second tube during the in
trol pulses to the grid of said ?rst tube to ren
creased conductivity thereof maintains said ?rst
der said tube non-conductive when the current
?ow in said device exceeds a predetermined
tube non-conductive.
6. An arrangement, as set forth in claim 5,
safety value whereby the voltage drop across 10
said ?rst resistance is reduced to a level at
wherein said ?rst and second tubes are contained
in a Single envelope and possess a common cath
which said device is rendered non-conductive,
means connecting the anode of said ?rst tube
ode.
7. In a rectifying circuit-arrangement provided
to the grid of said second tube whereby when
said ?rst tube is rendered non-conductive the 15 with a gaseous discharge device having a cathode,
conductivity of said second tube is increased
' an ignition electrode and a plate, said device be
ing interposed in an alternating-current circuit
thereby to develop a bias potential across said
second resistance, and means to apply said bias
to effect recti?cation, and means to apply an al
potential to the grid of said ?rst tube to main
ternating voltage to said ignition electrode pe
riodically to ignite said device, a protective system
tain same non-conductive.
.3. An arrangement, as set forth in claim 2,
preventing excessive current ?cw and back?re in
wherein said means to derive control pulses in
said device comprising ?rst and second electron
cludes a transformer having a primary connected
discharge tubes each having a cathode, a grid and
in series with said gaseous discharge device and
an anode, ?rst and second resistances, a source of
a secondary connected to a resistance element, a 25 anode potential having its negative terminal con
point on said element being coupled to the grid
nected to the cathodes of said tubes and its posi
of said ?rst tube.
tive terminal connected through said ?rst and
4. An arrangement, as set forth in claim 3,
second resistances respectively to the anodes of
further including a coupling capacitor connected
‘said tubes, a cut-off bias voltage source con
between the plate of said gaseous device and one 30 nected between the cathode and grid of said
end of the secondary of said transformer, where
device through said ?rst and second resistances,
by control pulses are applied to said element when
said ?rst and second resistances having values
said device back?res.
at which the combined voltage drop thereacross
5. In a rectifying circuit-arrangement provided
during the conduction of said ?rst tube has a
with a gaseous discharge device having a cath
magnitude counteracting the cut-off bias on said
ode, an ignition electrode and a plate, said device
device, means coupled to said alternating-cur
being interposed in an alternating-current cir
rent circuit to derive control pulses therefrom
cuit to effect recti?cation, and means to apply an
having an intensity depending on the current
alternating voltage to said ignition electrode pe
?ow through said device, means to apply said
riodically to ignite said device, a protective sys
control pulses to the grid of said ?rst tube to ren
tem preventing excessive current ?ow and back—
der said tube non-conductive when the cur
?re in said device comprising ?rst and second
rent ?ow in said device exceeds a predetermined
electron discharge tubes each having a cathode, a
safety value whereby the resultant voltage drop
grid and an anode, ?rst and second resistances,
across said ?rst resistance effects extinction of
a source of anode potential having its negative , said device, means connecting the anode of said
terminal connected to the cathodes of said tubes
?rst tube to the grid of said second tube whereby
and its positive terminal connected through said
the voltage developed at the anode of said ?rst
?rst and second resistances respectively to the
tube during the non-conduction thereof increases
anodes of said tubes, a cut-off bias voltage source
the conductivity of said second tube, means con
connected between the cathode and grid of said » necting the anode of said second tube to the grid
device through said ?rst resistance, said ?rst re
of said ?rst tube whereby the potential developed
sistance having a value at which the voltage drop
at the anode of said second tube during the in
thereacross during the conduction of said ?rst
creased conductivity thereof maintains said ?rst
tube has a magnitude counteracting the cut-off
tube non-conductive.
bias on said device, means coupled to said alter 55
KARL WALTER HESS.
nating-current circuit to derive control pulses
REFERENCES CITED
therefrom having an intensity depending on the
current ?ow through said device, means to apply
The following references are of record in the
said control pulses to the grid of said ?rst tube to
render said tube non-conductive when the cur
rent ?ow in said device exceeds a predetermined
safety value whereby the resultant voltage drop
across said ?rst resistance effects extinction of
said device, means connecting the anode of said
?le of this patent:
Number
UNITED STATES PATENTS
Name
Date
2,081,844
2,129,536
Winograd ________ __ May 25, 1937
Reid _____________ __ ‘Sept. 6, 1938