US1900013A - Protective system for fluid cooled tubes - Google Patents

Description

March 7, 1933. Y GEBHARD 1,900,013

PROTECTIVE SYSTEM FOR FLUID COOLED TUBES Filed Feb. 12, 1930 2 Sheets-Sheet 1 ,INVENTOR. $044443 01. swgmw,

ATTORNEY March 7, .1933.

Filed Feb. 12, 1950 L. A. GEBHARD PROTECTIVE SYSTEM FOR FLUID COOLED TUBES 2 Sheets-Sheet 2 3 p 4 T T v IN V EN TOR.

WM 61 425 aw By a ATTORNEY Patented Mar. 7, 1933 UNITED STAES PATENT OFFICE LOUIS A. GEBI-IARD, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO WIRED RADIO, ING, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE PROTECTIVE SYSTEMv FOR FLUID COOLED TUBES Application filed. February 12, 19-30. Serial No. 427,985.

My invention relates broadly to high power electron tube systems, and more particularly to a protective circuit for such systerns.

One of the objects of my invention is to provide an apparatus and circuit arrangement for protecting high power tubes against destructive efiects of high temperature during operation.

Another object of my invention is to provide a circuit arrangement and apparatus for cutting off the power circuits to a high power tube in the event that excessive temperature conditions should arise during the operation of the electron tube.

A further object of my invention is to provide a construction of protective device which is insertable within the fluid circulating jacket of a high power tube structure for operation under conditions of excessive temperature for cutting off the power circuits to the high power tube and thereby protecting the high power tube against destruction.

Other and further objects of'my invention reside in the construction of protective device which is insertable in the wall of the fluid cooling jacket of a high power tube structure for preventing injury to the high power tube structure upon excessive rise in temperature as set forth in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a fragmentary view of a high power tube mounted in a fluid cooling jacket and illustrating the temperature control mechanism with parts broken away and il lustrated in cross-section; Fig. 2 is a crosssectional view through the circuit controller on line 2-2 of Figure 1; Fig. 3 is a crosssectional view through the thermostatic con- 'trol means on line 33 of Figure 1; and

Fig. 4 is a circuit diagram showing the arrangement of thecontact system which controls the power supply to the high power tube.

Heretofore in the art various forms of protective systems have been proposed for high power tubes. Such systems have generally depended upon the temperature of the cooling fluid at a point adjacent the discooled inductance coil before reaching the control point which determines the condition of the circuit for supplying power to the tube. I have found that this form of control is often too remote to protect a tube against injury as delays occur before the control will act. To avoid this delay, I have devised an arrangement where the operation of the control is determined immediately at the point where the temperature is important and where destruction and injury to the tube may arise, that is, immediately adjacent the anode of the high power tube. I insert in one wall of the fluid cooling jacket, a member which transfers by conduction a portion of the heat existent immediately at the anode. A thermostatic element is operated by the heat thus transferred to control a contactor system which opens and closes the power control circuit for shutting down the tube and preventing operation of the tube at excessive temperatures.

The protective device is shown more fully in the drawings as comprising a metallic tube 1 inserted in the wall 2 of the fluid jacket 3 containing fluid cooled vacuum tube 4. The tube 1 has its inner end closed off and projecting into the path of the cooling fluid which flows as shown by the arrows in Fig. 1. The fluid passes upward over the surface of the anode 5 and between it and the wall of the tube 6 until it reaches the opening 7. From this point it passes through the opening between the wall'of tube 6 and the inner wall of the jacket 2 past the tube 1. The tube 1 is mounted as close to opening 7 as possible so that the heated fluid will reach it as soon as possible. On the tube 1 is mounted one end of bimetallic spiral strip 8. The other end of the spiral strip 8 is mounted on part 9 which is connected to insulating shaft 10. Insulating shaft 10 is supported at one end in a bearing in tube 1 as shown at 11 and is free to revolve. The other end of is supported in a bearing mounted on the frame of the radio transmitter as shown at 12. Shaft 10 is formed of insulation material of appropriate description for mechanically connecting the tube 1 while preventing any electrical connection therewith, as tube 1 is electrically connected to the anode of tube 3 and it is essential to prevent short circuiting the frame of the radio transmitter. The electrical connection between tube 1 and the fluid jacket is shown at 13. Tube 1 has a shoulder 14 and a threaded portion 15 on which a nut 16 may be screwed. Plate 17 is made of heat insulating material such as mica to isolate tube 1 from the wall 2 of the fluid jacket. This is to prevent conduction of the heat transmitted to tube 1 from the fluid being conducted away to the Wall 2. This permits the temperature to rise rapidly in tube 1 and in the bimetallic spiral S which is connected to the tube. Heat in sulating member 17 is made up in the form of a ring, the outer edge which is mounted in member 18 which is fastened to the wall 2 of the fluid jacket. A washer 19 and nut 20 provide a means for locking the member 1? in place. The heating of the bimetallic spiral 8 causes a turning of the shaft 10. Shaft 10 has mounted on it a cam 21 which actuates contacts 22.

This is shown more clearly in Fig. 2. The contact 22a-is mounted on an insulating arm 23 pivoted at 24. Contact 22b is mounted on a stationary insulating part 27. Contacts 22a and 22?) are held closed by means of spring 40. Wire 28 affords a connection to contact 22a. An adjusting screw 25 makes possible the setting of the particular point of engagement of this screw with cam 21. A. screw 26 permits the adjustment of the cam 21 with respect to the shaft 10. The shaft 10 is designed with a minimum cross-section to prevent too rapid conduction of the heat from tube 1.

The bearing 11 in tube 1 may be eliminated and the bearing supplied directly from the wall 2. This arrangement eliminates all possible paths of conduction of heat from tube 1 except through metallic spiral 8.

In Fig. 3, the method of attaching the thermo or bimetallic filament 8 between the shaft 10 and the heat transfer element 1 is shown more clearly. It will. be observed that expansion and contraction of the spiral 8 subjects shaft10 to a twisting force serving to operate the switch contacts. The bimetallic member must operate against the ten- .sion of's rin 10 in openin the contacts 22.

ID D

To secure the required motion, a multiplicity of spirals may be employed for the bimetallic member 8.

In Fig. 1, I have illustrated diagrammatically the contacts 226 and 22a connected in the power supply circuit 41 in circuit with momentary contact switches 29 and 30, and in circuit with relay windings 32 and 31 such that both the cathode circuit through transformer 33 and the anode circuit through switch 34 are opened when the temperature of the cooling fluid becomes excessive. I have illustrated the high power electron tube- 35 connected in a conventional power amplification circuit having an input system 36 and an output system 37. The power supply circuit for the anode is shown at 38. The cathode potential is supplied through 39. The biasing circuit for the grid system obtains its power from source 42. To prevent excessive radiation from bimetallic spiral 8 and prevent the influence of air currents in the radio transmitter, a shield or cover may be placed over the bimetallic spiral.

The bimetallic control element of my invention is very sensitive in its operation in;

that the temperature immediately at the high power tube is the controlling factor for effecting operation of the power supply relay circuits. The parts of the bimetallic element and switch mechanism may be relatively small. The protection which is obtained may mean the difference between sudden destruction and safety of a high power tube at times when a prolonged shut-down of the transmitter might prove highly disastrous.

While I have described my invention in a certain preferred embodiment, I desire that it be understood that modifications may be made and that no limitations upon my in vention are intended other than are imposed.-

by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A high power tube system including a high power electron tub-e including an electrode having an exposed surface, a jacket enclosing said electron tube and arranged for the circulation of a cooling fluid around said electrode. a thermally conductive element extending through said jacket, an an gularly shifta'ble shaft member journaled in said thermally conductive element. a thermostatic member extending between said thermally conductive element and said angularly movable shaft. a switch controlled by said angularly movable shaft, said switch operating to interrupt the power supply circuits to said electron tube under conditions of excessive temperature within the jacket surrounding said electron tube.

2. In a high power tube system, an electron tube having an electrode of exposed surface area, a fluid cooling jacket surrounding said electrode for the circulation of fluid around the exposed surface area of said electrode, a thermally conductive element extending through said jacket in the path of the cooling fluid therein, angularly movable shaft member having a switch on one end thereof and being rotatably mounted in said thermally conductive elementin the opposite end thereof, a thermostatic element extending between saidthermally conductive element. and said angularly movable shaft for angularly shifting the position of said shaft under conditions of excessive temperature in said fluid cooling jacket and operating said switch to open the power circuits to said electron tube.

3. In a high power tube system, an-electron tube having an electrode of exposed surface area, a fluid cooling jacket surrounding said electrode for the circulation of cooling fluid over the exposed surface of said electrode, a thermally conductive element projecting through said jacket, an angularly movable shaft member j ournaled in said thermally conductive element, a thermostat connected at one end of said thermally conductive element and connected at the other end to said a-ngularly movable shaft member, and a switch controlled by said shaft for opening the power circuits to said electron tub-e under conditions of excessive temperature within said fluid cooling jacket.

4. In an electron tube apparatus, a fluid circulating jacket enclosing an electron tube, a circuit control device comprising a thermally conductive member projecting into said fluid circulating jacket, an angularly movable shaft member, a switch controlled by one end of said shaft member, the opposite end of said shaft member extending into a socket formed in said thermally conductive member, and a thermostatic element connected between said thermally conductive mem her and said angularly movable shaft member and adapted to rotatably shift said angularly movable shaft member for opening or closing said switch.

5. In an electron tube apparatus, an electron tube having one of the electrodes thereof enclosed in a fluid circulating jacket, a thermally conductive member projecting into said jacket; said thermally conductive member having a socket formed therein, an angularly movable shaft member extending in axial alignment with said thermally conductive member with one end thereof projecting into the socket in said shaft member, a switch controlled by the opposite end of said shaft member, and a thermostatic element spirally disposed with respect to said thermally conductive member and said angularly movable shaft member, one end of said thermostatic element being connected to said thermally conductive member and the opposite end of said thermostat element being connected to said angularly movable shaft member for shifting said switch to either of two positions.

6. In a circuit controlling device, a temperature varying chamber, a hollow tubular socket member projecting into said temperature varying chamber, an angularly shiftable shaft member, one end of said shaft member projecting into said hollow tubular socket member, a switch device controlled by the opposite end of said shaft member, and a spirally arranged thermostatic element having one end thereof connected in heat conductive relation to said hollow tubular socket member and the other end thereof connected to said angularly shiftable shaft member and operating to impart angular movement to said shaft member for actuating said switch.

7. In a circuit controlling device, a heat conductive hollow tubular member projecting into a temperature varying chamber, an angularly'movable shaft member, a switch 'device operated by one end of said shaft member, the opposite end of said shaft ment ber projecting into said hollow tubular member, and a pair of spirally arranged strips of dissimilar metals connected at their inner ends with said hollow tubular member and connected at their outer extremities with said angularly movable shaft member, whereby heat transferred to said dissimilar metals serves to thermally expand or contract said members for imparting corresponding movement to said shaft member for actuating said switch.

8. In a circuit controlling device, a heat conductive hollow tubular member projecting into a temperature varying chamber, an angularly movable shaft member of insulating material, a switch device operated by one end of said shaft member, the opposite end of said shaft member projecting into said hollow tubular member, and a. thermostatic element having one end connected in a heat conductive relation with said hollow tubular member and the other end connected with said shaft member for controlling the operation or closing of said switch in a position isolated from said thermostatic element.

9. In a circuit controlling device, a ther mally conductive member extending into a temperature varying chamber, said member having a socket formed therein, a shaft member of insulating material having one end extending into said socket, a switch member controlled by the opposite end of said shaft member, a thermostatic element connected in heat transfer relation to said thermally conductive element at one end and connected to said shaft member at the other end, and means for adjusting the position of operation of said switch according to a selected temperature transferred by said thermally conductive element.

LOUIS A. GEBHARD.

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