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Патент USA US2121591

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2,121,591
R K. GESSFORD ET AL
GEID GLOW TUBE WITH ZERO TEMPERATURE EFEEcT'
' Filed Jan. - 10,
1936
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‘WITNESSES:
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ENVENTORs.
Dewey D; Know/e5 and
‘19055 K Gressford.
21,121,591
Patented June 21, 1938
UNITED STATES PATENT‘ OFFICE
' '7 2,121,591
GRID! cnovvv TUBE‘ WITH ‘ZERO TEMPERA
‘TUBE EFFECT
'
Ross K. Gessford and Dewey D'. Knowles, Wil
. kinsburg,,Pa., assignors to Westinghouse Elec
tric & Manufacturing Company, East Pitts;
burgh, Pa., a corporation of Pennsylvania
Application January 10, 1936, Serial 'No. 58,526
(01. 250--27.5)
' 7 Claims.
This invention ‘relates to'gas ?lled discharge
for grid control of currents.
It is an object of this invention to increase
5 the life of tubes and particularly to avoid the
limitation upon the life of the tube which can
be attributed to the clean-up action of the dis
'
'
glass.
_
‘
‘
It is a further object of this invention to pro
'
9
It is a iurther'object'oi thisinventionv topro
vide a shield in the form of a'cylinder surround
ing the anode and cathode and having a parti
It is a further object of this invention to-prO
vide such a grid with the part next to the anode
imperforate, and the remainder of the'grid con
25
30
V
1
It is a further object of‘this invention to pro
vide a structure of the class described in which
the cathode is situated between the partition
across the cylinder and a radiation shield sup
ported from the press.
It is a further object of this invention to provide
an atmosphere free from mercury in which the
discharge occurs.
5
"
It is a further object of this invention‘ to pro
vide in a gas-?lled tube free from mercury a cor
35 rectly chosen pressure whereby sputtering'is pre
vented and yet grid control is permitted; In a
tube of this sort with the pressure so chosen,the
life of the tube is greatly enhanced.
\
It is a further object of this invention to pro
40 duce a device of the class describedin which
the tube characteristics shall be constant ‘at ‘all
ordinary temperatures.
1
-'
-
'
It is a further object of this invention to pro
vide a discharge tube ?lled with ‘helium.
45 i It is a further object of this invention to pro
vide a structure whereby the gas pressure can be
increased above that used in conventional struc
tures still maintaining the control voltage limit
and giving lower tube drop, and increased life.
50
Other objects of the invention and, details of
the'structure will be apparent from the following
description and the drawing, in'which '
'
>
Figure 1 is a vertical sectional view through
the device, and
55
ing a press 2 in which are several standards. The _‘
speci?c illustration discloses three of these stand- @5'
ards although more or less may be provided. The
upper partof the press has a ?ange 4 which
across the press to the leads.
I} _
The cathode 1 consists of a coiled metallic rib- 10
bon coated with emissive oxides. It is supported
between two of the standards, 8 and 9, which ex~
tend through the press to external conductors.
These standards are welded to the ends of the w
ribbon and form the conductors to the heating 15
circuit. The standard 9 is connected by means
of a welded sleeve H] to a radiation shield II.
The standards 8 and 9 extendthroughperforations
in the shield .l I, the sleeve Ill being welded to the
radiation shield H at one of these perforations. 20
20 tion separating the anode and the cathode. ?
taining many perforations.
>
The device comprises a glass envelope I hav
affords a lengthy leakage path for any leakage
vide a shield surrounding the dischargepath and
145' acting to prevent ionization of the gas outside of
the shield.
'
~
It is a further object of this invention to so
16 arrange the electrodes that no discharge will
occur through the parts of the tube adjacent to
the
I
Fig. 1.
7 devices of the sort used to rectify currents and
charge.
.
in a vertical plane at right angles to that of
"
Fig.2 isla similar view,.the section being taken
The radiation shield is thus maintained at the
potential of one end‘ of the‘ cathode.
The anode is supported at the other endof the
envelope by means of a press l5 through which
a standard It extends. The standard‘ 16 is sur- 25
rounded by a glass skirt H which is continuous
with the press I5 and forms a lengthy path pre
venting leakage'to or from the anode l8. Exter
nal of the envelope the standard It is united
with a cap I9 affording convenient connection 30
means for the anode circuit.
.
The anode I8, the cathode 1 and the radiation
shield l l are surrounded by a cylindrical grid or
shield 20. A partition 2! is secured across the
cylinder 20 between the anode l8 and the cathode 35
l. The partition 2| is foraminate, the foramini
having diameters of about one-tenth of an inch.
For certain purposes it may be desirable to make
the cylinder 20 foraminate also, although a con
struction in which the portion above the partition 40
' 2| is devoid ofcperforations, or alternatively in
'
Which the entire cylinder '20 is imperforate is
within the scope of my invention.
No mercury is left in this tube when it is
?nished. It is ?lled with a noble gas of light 45 .
speci?c gravity, such as argon, neon or helium.
Best results have been obtained with helium.
Heretofore the pressure of the gas in the ?nished
tube is about 0.4 millimeter of mercury at work
ing temperature but with the new style of grid it 50
can be increased to 1.75.
, In the operation of the device, when the oath
ode has been heated by current through 'the
leads 8 and 9 and a potential is applied between
the anode l8 and the cathode, a discharge is set 655
2 .
2,121,591
up which extends from the anode 18 through
the perforations in the grid to the cathode 1.
lium that a pressure of 1.75 mm. of mercury
No discharge occurs in the space outside of the
grid, although such discharge can occur with a
grid foraminate over its whole extent. When
If a higher pressure of helium is used the con
trol by the grid at 750‘volts on the anode is lost.
We do not desire that the speci?c description
this tube is operating, a glow may be observed in
the space between anode and cathode, but it may
and illustration of one form of our device should
limit us to that speci?c form,. but we recognize
be seen that no such'gloW occurs outside of the
grid 20.
10
gives good results with the grid herein described.
that many modi?cations will occur to those
7 skilled in the art.
No limitation is intended ex
The reason for this we are not at present able
cept those required by the prior art or expressed 1O
to state with certainty, but it is our belief that l in the claims.
the metallic body 20, in addition to its action
We claim as our invention:
as a grid, acts also to absorb whatever ions col
1. In a gaseous discharge device, an envelope,
lide with it and thus prevent the formation of a cathode and an anode therein, a cylindrical
15 an are outside of it. The charges thus intro
grid'surrounding said anode and cathode, and 15
duced into the cylinder 20 are conducted by the electrically separate therefrom and a partition
connector 23 and over the lead 24 to whatever
across said grid separating said anode and cath
external connection is provided. For many pur ode, the portion of the cylinder on the anode
poses, the external connection is to one end of
side of said partition being imperforate and all
20 the cathode. We believe that the electrons from the rest of said grid being foraminate.
the cathode 1 will not penetrate the openings
. 2. In a gaseous discharge device, an envelope,
in the grid in su?icient number to set up ioniza
a cathode and an anode therein, a cylindrical
tion in the gas except in the line between the
grid surrounding said anode and cathode and a
cathode and the anode where the electrons perforated partition across said grid separating
25 possess a high velocity. The ions which they
said anode and cathode, the gaseous atmosphere 25
thus create by ionization of the gas neutralize within said envelope consisting of helium at a
the space charge and provide ready formation pressure of the order-of 1.75 mm. mercury.
for an are through the holes in the partition
3. In a gaseous discharge device, an envelope,
2|, but only a little ?eld from the anode l8 ex
a cathode and an anode therein, a cylindrical
30 tends into the space exterior to the cylinder 20
grid surroundingsaid electrodes and electrically
and, therefore, no such velocity can be given to separate therefrom and a perforated partition
the electrons which tend to emerge from the across said grid separating said anode and cath
cylinder. We do not wish to be limited by this ode, the cylindrical portion of the grid being
explanation because we are unable as yet to be
imperforate and extending past the anode into
35 sure why the discharge does not occur outside close proximity with the glass.
35
of the cylinder 20.
4. A gas discharge device comprising an en
When the gaseous discharge tubes known velope containing’ an anode and a cathode, a
heretofore are working, the discharge produces ?lling of a gas which is non-lique?able at ordi
a diminution in the pressure of the gas. ' When
this effect has proceeded so far that not suf?cient
gas remains to supply ions, ionization ceases and
the life of the tube is terminated.
We believe
that this effect of the discharge upon the gas
is most rapid when the discharge takes place
45 near the glass. We have observed but are not
yet able to explain that the clean-up effect of
the discharge upon the gas does not occur when
the discharge does not contact the glass of the
envelope. We, therefore, have provided that the
50 cylinder 20 extends beyond the anode l8 into
close proximity with the envelope I. The anode
I8 is unable, therefore, to have an arc extend
ing around the end of the cylinder 20 and
through the holes in the cylinder 28 to the oath
55 ode 1. There being no discharge in proximity to
the glass, there is little or no clean-up effect
noticed. The tube, therefore, can last inde?
nitely.
_
~
When desired the shield is connected through
nary room temperature and pressure, the pres
sure of said gas being of the order of 0.4 mm. 4.0
to 1.75 mm. mercury, and a‘ conductive member
surrounding said anode and cathode and ex
tending into close proximity to said envelope in
the region of the anode, said-member having a
perforated partition extending across its in 45
terior to separate said cathode from said anode.
I 5. A gas discharge device comprising an en
velope containing an anode and a cathode, a
?lling of helium at a pressure of the order of
1.75 mm. mercury, and a conductive member 50
surrounding said anode and cathode and ex
tending into close proximity to said envelope in
the region of the anode, said member having a
perforated partition extending across its interior
to separate said cathode from said anode.
6. In a gas discharge device, an anode, a cath
ode, and a conductive member surrounding said
anode and cathode and having a perforate por
tion transverse to the region between them, said
member being foraminate throughout the por
60 the lead 24 to an external source of potential.
The potential of the grid may be'varied accord- ' tion nearest the‘cathode and imperforate near
ing to any desired ?ow. One well known flow
which we have found useful is to keep the grid
su?iciently negative to prevent an are forming
65 until a predetermined point in the cycle of al—
ternating potential is reached and then permit
it to become su?iciently positive to permit an
arc to form. The are will then continue until
the anode potential has become zero.
70
If the tube be ?lled with mercury-free gas
the pressure may be so high that no potential
on the grid will prevent the are from forming.
If the gas pressure be too low sputtering at the
cathode will be so rapid that the life of the tube
75 is shortened thereby. We have found with he
the anode, the imperforate portion extending
beyond the' anode.
7. In a gas discharge device, an envelope, an
anode, a cathode, and a conductive member sur 65
rounding said anode and cathode and having a
perforate portion transverse to the region be
tween them, said member being foraminate
throughout the portion nearest the cathode and
imperforate near the anode, the imperforate
portion extending beyond the anode into close
proximity to the envelope.
ROSS K. GESSFORD.
DEWEY D. KNOWLES‘.
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