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Патент USA US2130204

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Sent. 13, 1938.
Filed July 2, 1957
Patented Sept. 13, 1938
Warren G. Taylor, Chicago, Ill.
. Application July 2, 1997. serial No. 151,690
9 claims.
This invention relates to vacuum tubes and
particularly to the construction of the anodes
therefor. As is well known, the impedance of
a vacuum tube is a function of the distance be
tween the opposing electrode surfaces.
Thus, if
the anode and cathode are separated by a greater
distance under similar grid conditions, the im
I pedance of thetube goes up, while the capacity
goes down. It is generally desirable to haveV a
10 low capacitance but for the most purposes it is
also desirable to have a lowimpedance.
To attain the above object, the main body of
the anode is preferably disposed at a substantial
distance from the cathode so that a desired mini
15 mum capacitance exists. In order to reduce the
impedance, however, I dispose a plurality of wing
members on the inside of the anode surface ex
tending toward the cathode. This results in a
distortion of the electrostatic ñeld and tends to
divert a substantial portion of the electron stream
directly to these wing members.
These wing members are preferably of tan
talum and are so designed with regard to thick
ness and operating conditions that during the
25 normal operation of the tube, the tantalum wings
are heated at least to a dull red heat. Under
such conditions, tantalum has the property of
acting as a getter and cleans up whatever gases
and vapors may be present'within the tube.
3 O Preferably, the anode proper may begmade of
graphite which, as an anode, is particularly de
sirable. Because of black body radiation, a car
bon electrode may be run much more efficiently
than other electrodes.
The most serious disad
35 vantage up to date with graphite electrodes or
any other form of carbon, has been the difficulty
of complete removal of absorbed gases. It fre
quently happens that in the course of time, a
graphite electrode, particularly under severe over
load, will give up some gas and render the tube
gassy. Of course, the usual getter will absorb
a certain amount of gas, but, in many instances
the evolution of gas from the carbon electrode
4 far exceeds the gettering ability of the substance
generally used. With tantalum, however, it is
possible to absorb a substantial quantity of gas
and the absorption is most efficient when the
tantalum is just below white heat. By proper
50 design of the tube, it is possible to have such
operating conditions under severe overload when
the graphite anode is most likely to evolve gas.
This gettering action is preferably supplemental
to the usual getter, although, of course, if enough
55 tantalum be provided in the form of wings, the
(o1. 25o-27.5) .
usual getter capsule may be reduced in quantity
or even eliminated. j
Referring to the drawing:
Figure'l is an elevation partly in section of a
tube embodied in this invention.
Figure 2 is a section along line 2_2 of Figure 1.
Figure 3 is a detail of one form of tantalum
-The tube comprises an envelope IU of glass or
any other material, having reentrant stems I I and
I2 at opposite ends terminating in presses I3
and I4.
Sealed in press I3 are a plurality of
wires including a pair of filament leads I6. Sup
ported by leads I6 is an electrode structure com
prising a pair of spaced insulators I8 and I9
each in the shape of a cross, although any other
shape may be used if desired. Passing upwardly
through the’mid-portion of insulator I8 is a ñla
ment 28, the top of which 2| is maintained taut
by a spring 22 pressing against the outer surface 20
of insulator I9. Inasmuch as this construction
is well known, further details in regard thereto
are unnecessary. DisposedV aroundA filament 2U
and, it is understood, of course, Ythat an indi
rectly heated cathode may be used if necessary, 25
is a grid 23 held by grid posts 24 and 25. The
grid.y posts 24 and 25 pass through opposed arms
of insulators I8 and I9. The remaining arms
of insulators I8 and I9 have a pair of rods 21
and 28‘passing therethrough which support the 30
The bottom of rods 2l and 28 are pref
erably ‘enlarged at 29 and 39 to prevent them
from- being pulled up through insulator I8. Im
mediately above insulator I8 and around each
rod are sleeves 3| and 32 which act to space an 35
anode 35 above insulator I8. Additional sleeves
36 and B‘Ifabove anode 35 and below insulator
I9 are also provided for spacing purposes. Above
insulator I9, sleeves 38 and 39 are provided. A
pair of support wires 40 and 4I sealed in press
I4 are welded to the free upper ends of wire rods
21 and 28 to maintain 'the entire assembly intact.
The usual getter pole 42 supported by a wire 43
may be disposed in any suitable manner as toy
support rod 4I. Both support rods 4B and 4I
are at anode »potentialV andy are connected to an
anode terminal 45 sealed on the outside of the
tube. The ñlament leads I6 going through the
bottom press I3 may be connected to suitable
prongs 46 and 41 disposed in a base 48. The grid 50
posts are prevented from moving vertically by
means of straps 49 Welded to the posts above and
below insulator I8 and a connection to the grid
is made by wire 5U and lead 5I welded to a lead
52 sealed into the envelope. A metal cap 53 55
cemented to the glass tube serves as a connection
to the grid.
Referring to the anode in greater detail, this
electrode is preferably of graphite although it
is to be understood, that this invention is not
especially during coagulation, the currents may
rise to high values and for short periods of time
may result in severe overloads. Such conditions
are normal for this class of service. Hence, any
tube which is used in a device of this character Ul
limited thereto.
The anode proper may be of any
suitable metal or material, but in the preferred
must withstand severe overloads as part of its
normal use. The tube herein disclosed is useful
form, graphite is used. As shown, the anode
has its inner surface 60 ñnished off to provide a
for such service and has been found to be unusu
flattened cylindrical cross-section.' As clearly
shown in Figure 2, graphite has substantial thick
ness and is provided with a plurality of steps 6|
and 62 where the support rods 21 and 28 pass
ally satisfactory.
What is claimed is:
1. A vacuum tube comprising an evacuated re
ceptacle having a cathode and a carbon anode
and tantalum vanes electrically connected to said
through. As clearly shown, these support rods anode and extending toward said cathode and be
pass through the thickest portion of the anode~ ing so proportioned that during normal operating
so that ample mechanical strength is assured.
conditions said vanes are heated to at least dull
Disposed along the inside surface and prefer
ably along the flattened portion 64 thereof, is a.
tantalum member 65 comprising a flat back mem
ceptacle having a cathode and a carbon anode
surrounding the cathode, said anode having a 20
plurality of tantalum vanes extending from the
inside surface thereof toward said cathode and
ber 66 having a pair of wing extensions 61 and
68 extending at right angles thereof. Back 66
has the upper and lower ends 69 and 10 bent
along lines 1I and 12 just beyond the ends of
wings 61 and 68; Beyond lines 1| and 12, the
ends are bent parallel to Aeach other and at right
2. A vacuum tube comprising an evacuated re
being adapted under normal operating conditions
to be heated at least to a dull red.
3. .A vacuum tube comprising an evacuated re
angles to back 66 for a short distance and from
the mid-portion of each end small fastening ears
15 and 16 are provided. As clearly evident in
ceptacle having a cathode and an anode therein
and a tantalum member carried by said anode
having wing portions extending edgewise toward -
Figure 2 of the drawing, back 66 is adapted to
said cathode and during normal operation of the
tube being at least at red heat, and means in 30
cluding at least one hinge portion on said tanta
lum member for preventing buckling of the mem
30 fit against the inside surface ofY anode 35, while
the two wings 61 and 68 extend outwardly to
ward grid 23. The bent flanged ends 69 and 10
fit over the top and bottom surfaces 11 and 18
of anode 35 while ears 15 and 16 are adapted
to be disposed against the sleeves on both sides
of the anode. By spot~welding ears 15 and 16
to the corresponding sleeves the entire wing con
struction is rigidly maintained in position.
While the member shown in Figure 3 is pro
40. vided with two wings, it is> understood, of course,
that as many wings may be provided as may
be desired. During the operation of the tube,
the plurality of bends at each end of back
section 66 provide hinges which yield and permit
45. the wings and the back section 66 to expand
when heated. In order to maintain the charac
teristics of the tube at a constant value, it‘is
important that buckling of the wings be pre
vented and a constant distance between the
- wings and grid be maintained. By the construc
tion disclosed herein, heating of the anode and
particularly of the wings, merely results in elon
gation and has no effect on the cross-sectional
relationship of the electrodes. During the oper
ation of the tube, wings 61 and 68 become hot
enough so that a decided gettering action results,
While at the same time the electron path is
shortened sufficiently to reduce the impedance of
the tube. .
ber due to heat.
4. A vacuum tube comprising an evacuated
receptacle having a cathode and an anode sur
rounding the same, and a tantalum member dis
posed on the inside surface of said anode and
having wings extending toward said cathode
edgewise and during the normal operation of the
tube being adapted to operate at least at a red 40
heat and means for supporting said tantalum
member on said anode whereby said wings may
expand when heated without substantially chang
ing their distance from said cathode.
5. The tube of claim 4 wherein said supporting „
means comprises a bent member at each end of
the tantalum member adapted to take up the
expansion of said tantalum member under heat.
6. The tube of claim 4 wherein said anode is
of graphite.
'7. A vacuum tube comprising an evacuated re
ceptacle having a cathode, a grid surrounding
said cathode and an- anode surrounding said grid,
and one or more tantalum vanes extending from
the inside surface of said anode edgewise toward
said cathode and spaced from said cathode at
such a distance that under normal operating tube
conditions such vanes glow at least at red heat.
8. The tube of claim 7 wherein said anode is of
By the term, normal operating conditions, as
hereinafter used in the claims, is meant, not only
the normal load for which a Ytube is rated, but
also overloads which are customarily encountered'
members are mounted at their ends at the ends
in service. Thus, in electric cautery machines, it
is customary to have a high frequency generator
supply cutting or coagulating currents. At times,
take'up the expansion of said tantalum under
' 9. The tube of claim 7 wherein said tantalum
of the anode, said mounting ends being bent to_
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