US2910601A - Thermostatic mounting structure for electron discharge device - Google Patents

Description

THERMOSTATEC MOUNTING STRUCTURE FOR ELECTRON DISCHARGE DEVICE Filed July 23. 1956 27, 1959 P BEAVENBOER 2,910,601

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IN VEN TOR: PIE TER BRAVENEOER arrnannros'mnc MOUNTING i STRUCTURE. FOR

- "EIZECTRONDISCHARGEDEVICE .FPieter Bravenboer,.Eindhoven, Netherlands, \assignor," by

mesne assignments, to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware Application July 23, 1956, Serial No. 599,644

Claims priority, application Netherlands July 27, 1955 1 Claim. (Cl. 313) This invention relates to means for mounting a thermostat on electron discharge devices, such as ignitrons, having a double-walled water jacket constructed integrally with the tube.

In tubes which are required to carry large electric currents, of which the ignitron is an excellent example, it is necessary to provide means for cooling the tube wall. For this purpose it is common to provide a double-walled structure, the inner wall enclosing the operating tube elements and the outer wall cooperating with the inner wall to form a water jacket. Water in sufiicient quantity to keep the inner wall below a predetermined temperature at all times flows through the space between the inner and outer walls. However, ignitrons so constructed are frequently used in welding apparatus where the current load is not continuous and where it is unnecessary to provide a continuous flow of water through the water jacket, although it is essential that the supply of water during periods of peak current be sufficient to keep the inner wall of the tube below the rated temperature. In order to adjust the flow of water to the cooling requirement of thetube, a thermostat may be attached to the tube to operate a water supply valve during the periods when the inner wall exceeds the rated temperature.

The primary object of the invention is to provide good thermal conducting means between the inner wall of an integrally water-jacketed tube and a thermostat outside the water jacket. It is an additional object to provide such thermal conducting means in a form immune to the forms of scale or corrosion and to seal the thermal conducting means into the water jacket so as not to require gaskets which are subject to leakage.

The present invention comprises a block of thermally conductive material securely attached to the inner wall of the electron discharge device and extending out to the inner surface of the outer wall. Outside of the outer wall is a second block of thermally conductive material which is in intimate contact with the outer wall immediately over the inner block and which is preferably provided-with direct thermal contacting pins or screws extending through the outer wall and into the inner block and soldered in place to prevent leakage. The outer block serves as a thermal contacting element for a thermostat and also as a base on which the thermostat can be mounted.

The invention will be further described in connection with the drawings in which:

Fig. l is a partial cross-sectional view of a doublewalled electron discharge device including thermal contacting elements constructed according to the invention;

Fig. 2 is a side cross-sectional view of the elements in Fig. 1;

Fig. 3 shows a complete ignitron including the thermostat mounting block of the invention.

In Fig. 1 the wall 1 is the inner wall'of an electron discharge device such as an ignitron and is the wall which ice 1 tmustlbe maintained .below ar critical temperature. Reference. character-.2 .designates. aconcentric outer wall which -...cooperates with the-inner walll :toforma water jacket completely surrounding .the inner wall 1. toftgood thermal conductingmaterial, such as copper,

A slab 3 made to fit the shape ofrthe-outerwallszaandsattached thereto by means of a pair of pins, or bolts 4 which extend through the outer wall 2 into an inner cylindrical segment. 5, which is also made of good thermal conducting material such as copper. The pins or bolts 4 are preferably soldered or otherwise sealed to the outer wall 2 so as toprevent water leakage.

A thermostat 6 is clamped to the slab 3 by means of a strap 7 which is secured by a pair of bolts 8. Thermostat 6 is a well-known type of thermostat and is provided with electrical connections 9 mounted on a terminal block 10. These electrical connections may be connected to relays to control the flow of water through the space between the inner wall 1 and the outer wall 2 in response to temperature changes of the inner wall caused by variations in the current drawn through the tube.

Fig. 2 is a cross sectional view of these elements which form permanent parts of the tube but does not show the thermostat and its associated elements. It will be observed in Fig. 2 that the cylindrical segment 5 is pro vided with a pair of flanges 11 and 12 by which it may be Welded to the inner wall 1 of the discharge device in order to assure good thermal contact to the inner wall and at the same time to prevent the possibility that scale may be formed between segment 5 and wall 1 which would interfere with the thermal connection and would give false readings on the thermostat shown in Fig. 1. It is important to provide a good thermal connection from the inner wall 1 to the slab 3, although it is desirable that the thermal contact be not so perfect as to cause excessively slow response to an increased supply of cooling water. This may be explained as follows. The interval side of the inner wall will have a certain temperature to maintain the vapour within the tube. The outer side should have lower temperature to make possible a heat flow to the exterior. If new the thermal contact between the slab 3 and the wall 1 would be perfect, the temperature of the cooling water would not influence the temperature of the slab 3, because the water contacts the ,segment 5 only at the edges which have a surface area that is small compared to that of the segment itself. This difficulty is avoided by making the thermal contact less perfect. a

Fig. 3 shows a side view of a complete ignitron incorporating the thermostat mounting elements shown in Figs. 1 and 2 and in addition showing an inlet pipe 13 and outlet pipe 14 to be connected to a source of cooling water.

Although the invention has been described in terms of single embodiment, it will beobvious to those skilled in the art modification may be made therein within the scope of the following claim.

What is claimed is: 1

An electron discharge device comprising an inner wall which must be kept below a predetermined temperature; an outer wall cooperating with said inner wall to form a water-tight compartment through which water may flow to cool the inner wall; and a contact structure adapted to provide thermal contact between the inner and outer walls and a thermally responsive member, said contact structure comprising: an inner segment of thermally conductive material attached to the inner wall to make good thermal contact therewith, said segment having a plurality of flanges secured to the inner wall to further provide good thermal contact between said segment and A 0 the inner wall and to prevent the formation of scale References Cited in the file of patent between the inner wall and the segment; an outer segment of thermally conductive material attached to the outer wall to make good thermal contact therewith and to support a thermally responsive member in good thermal between, said latter means being sealed to said outer wall to prevent water leakage.

UNITED'STATES PATENTS Kercher Aug. 8, 1916 Schwimmer Feb. 16, 1926 Springer' L Aug. 13, 1929 Spencer July 4, 1933 Huber June 20, 1939 Pearson May 23, 1944 Keating Aug. 5, 1958

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