US2114345A

US2114345A - Radio-frequency applicator with electroscopic control

Info

Publication number: US2114345A
Application number: US719978A
Authority: US
Inventors: Elmer R Hayford
Original assignee: JOSEPH K DAVIDSON
Current assignee: JOSEPH K DAVIDSON
Priority date: 1934-04-10
Filing date: 1934-04-10
Publication date: 1938-04-19
Anticipated expiration: 1955-04-19

Description

April 1938. E. R. HAYFORD 2,114,345

RADIO-FREQUENCY APPLICATOR WITH ELECTROSCOPIC CONTROL Filed April 10, 1934 INVENTOR v Patented Apr. 19, 1938 PATENT OFFICE RADIO-FREQUENCY APPLICATOR WITH ELECTROSCOPIO CONTROL Elmer R. Hayford, Rochester, N. Y., assignor, by mesne assignments, to Joseph K. Davidson,

Rochester, N. Y.

Application April 10, 1934, Serial No. 719,978

5 Claims.

My present invention relates to electrical devices and more particularly to the generation, use and control of radio frequency power, and it has for its object to provide an apparatus of this character that will be simple in construction and operation and by means of which the radio-frequency power may be put to such uses as destroying bacteria and other small animate life. A further object of the invention is to provide automatic means for controlling radio frequency output from a generator through an output inductance element, preferably, to a field inductance correlated or coupled therewith whereby an electrostatic field maintained across the inductance may be regulated for the dissipation in matter placed therein of all electrostatic energy without changes of any consequence in the power derived from the radio-frequency generator.

To these and other ends, the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawing:

Fig. 1 is a top plan composite view of an apparatus constructed in accordance with and illustrating one embodiment of my invention, parts thereof being conventionally illustrated and the view being partially diagrammatic to include in enlarged side elevation the compensating or controlling device for the electrostatic field of the capacity electrodes;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. l, and

Fig. 3 is an elevation of the controlling device taken from another side.

Similar reference numerals throughout the several views indicate the same parts.

Referring more particularly to the drawings, I indicates a base upon which is shown mounted at one end the tubes 2 and condenser 3 having the usual knob control 4 of a radio-frequency generator. The condenser is connected by wires 5 with an output inductive element 6 in the form of a coil having its circuit-connected ends supported on insulated standards I on the base. Opposite this coil is a similar inductive electromagnetic field coil 8 similarly mounted on insulated standards 9. Beyond this are insulated tables H) on the base supported by standards H on which are arranged in spaced opposition to each other two capacity electrodes I2. These are, respectively, connected by wires I3 to the terminals of 8, whereby an electrostatic area or space M is created between the electrodes l2, Ar-

ticles or matter of any kind placed in this area are subjected to the capacity power to an extent that has been found to destroy bacteria and other small animate life. In the present instance, I have shown as an example a bottle of beer B 5 occupying this area for pasteurization purposes. The beer or similar articles may be carried in procession through the area as a continuous treatment by a suitable overhead conveyor .l5.

The interposition of a body B in the electro- 10 static field area M, of course, results in an interference that alters the capacity of the electrodes l2 which would ordinarily affect the power and be compensated for by readjustment of the output through condenser 3 to hold the power uni- 15 form. This variable, however, is also contingent upon both the area and degree of separation of the electrodes l2 and is very sensitive to differences in the mass of the interposed article B. It is not practicable to change either contingent condition to suit individual articles. I, therefore, provide another means of compensation that is automatic in operation and does not involve any change in the output or manipulation of the condenser 3. This means consists, in the present instance, of the following:

Hooked up in parallel with the electrodes l2 at a not too remote point through wires I6 is a pair of auxiliary electrodes l1 and I8 which I prefer to enclose in a vacuum tube l9. One of 30 these, IT, has an outwardly curved transmitting face turned toward the other, as shown in Fig. 1, and is pivotally supported at Hi on a support 20 so that it is free to, swing toward and from electrode I8. The effect of the electrostatic action 35 between the two being to draw them together and electrode I! being free to swing and narrow the gap between it and electrode l8, when the capacity at I2 is increased through the presence of article B, electrode l1 compensates by swing- ,ing away from electrode l8 which is equivalent to electrodes l2 themselves being separated or their areas decreased. The curvature of element l1 maintains a tangent line of radiating surface that is constant in relation to the surface at l8, whatever the degree of separation. Auxiliary electrodes I1 and I8 and support 20 constitute an electroscopic control unit.

With this arrangement, all electrostatic energy in the field area 'M is rendered constant and is available for dissipation in the matter represented by article B, so eliminating the necessity of changes in the frequency of the radio frequency generator to balance the electrode capacity changes as the different articles pass 55 under treatment and resulting in a constant cur-. rent flowing through the electrode l2, so that all articles are treated uniformly regardless of their mass.

I claim as my invention:

1. The combination with a radio frequency generator provided with an output inductance element, of a field inductance correlated with the latter, a pair of capacity electrodes in the circuit of the inductance having a uniformly maintained area and degree of separation in operation, and compensating means in parallel circuit therewith for maintaining uniform power between the field electrodes to overcome intermediate interference, said compensating means embodying a second pair of electrodes one of which is pivoted to move toward and from the other in response to the electrostatic stress existing between said second pair 01 electrodes and one of which is provided with a curved transmitting surface convexly opposed to the opposite electrode.

2. The combination with a radio frequency I generator provided with an output inductance element, of a field inductance correlated with the latter, a pair of parallel surfaced capacity electrodes in the circuit of the inductance having a uniformly maintained area and degree of separation in operation at all times, means for introducing in succession a plurality of articles to be treated as separate bodies in the field between the two capacity electrodes, and an automatic compensating means in parallel circuit therewith for maintaining uniform power between the field electrodes to overcome intermediate interference of different degrees by the respective articles, said compensating means embodying a second pair of electrodes having a variable in the stated respects in which the first pair are uniform.

3. In a high-frequency field applicator, a source of high-frequency voltage, a pair of capacity plate electrodes connected to said source and spaced for the reception therebetween of objects to be treated, and an electroscopic control unit connected in parallel with said plate electrodes and comprising a pair of. fixed conducting plates mounted in mutual capacity relation and further comprising a movable conducting plate movably supported between said fixed plates by a first one of said fixed plates in electrical conducting relation with said first one of said fixed plates for variation of the position of said movable plate relative to said fixed plates responsive to the voltage applied to said fixed plates.

4. In a high-frequency field applicator, a source of high-frequency voltage, a pair of capacity plate electrodes connected to said source and spaced for the reception therebetween of objects to be treated, and an electroscopic control unit connected in parallel with said plate electrodes and comprising a pair of. fixed conducting plates mounted in mutual capacity relation and further comprising an arcuate movable conducting plate member movably supported between said fixed plates by a first one of said fixed plates in electrical conducting relation with said first one of said fixed plates for variation of the position of said movable plate member relative to said fixed plates responsive to the voltage existing across said fixed plates, said arcuate member being positioned with its convex side toward the second one of said fixed plates.

5. In a high-frequency field applicator, a source of high-frequency voltage, a pair of capacity plate electrodes connected to said source and spaced for the reception therebetween of objects to be treated, and an electroscopic control unit connected in parallel with said plate electrodes and comprising a pair of. fixed conducting plates mounted in mutual capacity relation, a first one of said fixed plates having a reentrantly bentover terminal portion, said unit further comprising a movable plate member pivotally conductively supported by said bent-over terminal portion of said first one of said fixed plates between said plates for variation of the position of said movable plate member relative to said fixed plates responsive to the voltage existing across said fixed plates.

EIMER R. HAYFORD.