US2510017A

US2510017A - Radio-frequency oscillator for ultraviolet ray generators

Info

Publication number: US2510017A
Application number: US675353A
Authority: US
Inventors: Furedy Frank; Carl E Atkins
Original assignee: SUN KRAFT Inc
Current assignee: SUN KRAFT Inc; SUN-KRAFT Inc
Priority date: 1946-06-08
Filing date: 1946-06-08
Publication date: 1950-05-30
Anticipated expiration: 1967-05-30

Description

May 30, 1950 F. FUREDY ET AL 2,510,017 RADIO FREQUENCY OSCILLATO OR ULTRAVIOLET RAY GENERAT Filed June 8, 1946 2 Sheets-Sheet l W 1950 F. FUREDY ET AL 2,510,017

RADIO FREQUENCY OSCILLATOR FOR ULTRAVIOLET RAY GENERATORS Filed June 8, 1946 2 Sheets-Sheet 2 Patented May 30, 1950 RADIO-FREQUENCY OSCILLATOR FOR ULTRAVIOLET RAY GENERATORS Frank Furedy, Chicago, and Carl E. Atkins, Elgin, 11L, assignors to Sun-Kraft, Inc., Chicago, 111., a corporation of Delaware Appiication June 8, 1946, Serial No. 675,353

1 Claim. 1

The present invention relates to an apparatus and circuit for an ultraviolet or like therapeutic lamp.

Heretofore in ultraviolet or like therapeutic lamp, there have been devised one or more electrodeless tubular gaseous discharge tubes which were energized by high frequency oscillating current. Generally the gaseous discharge tube which has a tubular quartz envelope has been operated as a cold quartz ultraviolet lamp. The lamp or tube is mounted in a radiant energy reflector supported by a structure so as to permit a certain amount of flexibility in the positioning of the re flector.

For professional use the reflector must be mounted on a supporting stand and apparatus which permits the maximum degree of flexibility in adjusting the position of the reflector with respect to angular disposition and height so that the radiant energy may be directed toward desired portions of the anatomy of the patient being treated. The source of high frequency energy constitutes a suitable oscillating circuit which in the past has been conveniently located in a compartment adjacent the bottom of the base of the lamp structure. A concentric transmission line interconnects the oscillator with the discharge tubes in the reflector.

In any professional type of therapeutic or ultra violet lamp, it would be desirable to have consid-- erable flexibility in the use of the lamp, so that either one or two discharge tubes may be energized at a time thereby to control to a certain degree the intensity of the radiant energy.

It, furthermore, would be desirable to utilize the same source of oscillations for energization of local applicator types of discharge tubes. Certain of the local applicators are designed particularly for oral cavities and others are designed to provide a concentrated beam or spot of radiant energy. If such an arrangement were to be provided with the location of the oscillator in the base of the equipment, it would be necessary to provide suitable matching or tuning devices so as to provide the proper impedance relation relative to the discharge device, the transmission line, and the oscillator.

In order to obviate the necessity for these devices and to simplify the construction, the present invention provides an improved compact oscillator which is located directly adjacent the reflector thereby eliminating the need of any transmission lines.

In accordance with the present invention a new improved circuit is also provided which per- 2 mits the desired degree of flexibility in the use of the device so that either one or both of the gaseous discharge tubes mounted in the reflector may be energized or the oscillator may be used to supply energy to a suitable local applicator.

An improved circuit producing a higher potential radio frequency output is also provided with suitable control or switching means to obtain the desired flexibility in use.

It, therefore, is an object of the present invention to provide an improved ultraviolet or like therapeutic lamp structure particularly suited for professional use.

It is a further object of the present invention to provide an improved ultraviolet or therapeutic lamp structure which is particularly designed for flexibility in use.

It is another object of the present invention to provide a new and improved circuit for generating radio frequencies for the energization of any one or all of a plurality of gaseous discharge tubes.

Other and further objects of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein Figure 1 is a perspective view of the reflector and housing for the gaseous discharge tubes;

Figure 2 is a front view of the radio frequency oscillator chassis associated with the gaseous discharge tubes;

Figure 3 is a plan view of the oscillator apparatus shown in Figure 2; and

Figure 4 is a schematic circuit diagram of the oscillators of Figures 2 and 3.

The perspective View of Figure 1 shows the upper extremity [0 of an upright support member mounted on a suitable base. The member it may be part of a telescopic adjustable member so that the height of the reflector may be readily adjusted. A suitable stop screw 22 is provided for controlling the horizontal angular relation of a suitable drum support I4. The drum support I i carries an arm support it and is provided with a locking lever I8 so that the angular relation between the arm support and the drum support may be maintained. The arm support l t has a bifur-- cated sleeve portion which may be clamped together by a suitable locking arrangement includ ing the lever 20.

The arm support It carries an arm 22 having at its outer extremity a U-shaped supporting bracket 24 which engages suitable trunnions 26 mounted on a housing structure 28. The housing structure 28 carries a radiant energy reflector 39 which is provided with suitable mounting clips 32 for a pair of

gaseous discharge tubes

34 and 36. The end portions 38 of the housing 28 may be provided with suitable Ventilating holes 46 to provide adequate ventilation for the high frequency oscillators which are mounted on a chassis between the reflector 39 and the housing 28. On the exterior of the housing at one side there is provided a socket or receptacle 52 for receiving the plug connector of a local applicator discharge device. Adjacent the socket 42 is a control knob 64 and a dial 56 for controlling and indicating the selective operation of one or both of the

tubes

34 and 36 or the local applicator connected to the socket 42.

Referringto Figures 2 and 3 it will be seen that immediately above the reflector so there is located a chassis 43 which supports two compart ments 59 and 52 containing the components for two similar oscillator circuits. Mounted upon a suitable bracket 54 on the chassis G8 is a control or selector switch 56 having a chassis which carries the knob ed. The socket d2 for the local applicator is located adjacent the bracket 55 and is suitably supported from the chassis 58. The socket 42 is connected to suitable terminals on the selector or control switch 96. The scaled compartmentor case 59 which contains the circuit components for a pushpull radio frequency oscillator is provided with a pair of sockets 59 for a pair of vacuum tubes $6. The sealed case or compartment 59 may be secured to the base 48 by suitable fastening means passing through a flange or bracket 52.

In a similar manner the other compartment or sealed case 52 contains the circuit components for another push-pull oscillator and which may likewise be secured to the base 8 by suitable fastenin'g means extending through a bracket or flange 64. The case 52 contains a pair of sockets 66 for a pair of vacuum tubes 69. The cases or compartments 59 and 52 are provided with grommet insulated apertures l9 and 72 through which pairs of electric conductors I i are passed to supply alternating current power. The conductors I l commonly are connected to a timing device so that sixty-cycle alternating current power is supplied for a definite time thereby to control the total time of treatment.

Two conductors I6 and I8 extend from the a} oscillator circuit within the sealed compartment 52 to the selector switch 56. Two conductors 39 and 82 extend from the oscillator circuit within the sealed compartment 59 to the selector switch 59. Two conductors 9 5: and 8f, extend from op-- posite ends of the discharge tube 94 to the switch 56 and two other conductors 88 and 99 extend from the other discharge device 36 to the switch 56, and two

conductors

92 and 94 extend from the socket 42 to the switch 56. The

discharge devices

34 and 36 are supported in suitable clips 32 which in turn are mounted on suitable insulating or bushing members 96 which pass through both the chassis 48 and the radiant energy reflector 30. The oscillator circuit contained in the sealed compartment 5|] has a pair of vacuum tubes 60 which may be of the power tetrode or pentode type such as a ll'lL'lGT which also contains a half-wave rectifier in the same evacuated envelope. The cathodes of the tetrode portions BI and 63 of the vacuum tubes 69 are connected together and to one of the conductors 74. The screen grids are connected to a suitable source of potential derived from the voltage doubler circuit. A by-pass condenser 98 is connected between the conductors which are c0nnected to the cathodes and the screen grids. A tank circuit inductor I00 has one end connected directly to the anode of the tetrode portion iii; of the vacuum tubes 50, and an intermediate point on the conductor is connected to the other anode of the tetrode portion SI of the vacuum tubes 60.

The outer extremities of the tank circuit inductor I00 are connected by isolating capacitors I62 and I 94 to the conductors 89 and B2 respectively. The midpoint of that portion of the tank circuit inductor I99 which extends between the two anodes of the vacuum tube portions 6! and 63 is connected by a conductor I66 to the voltage doubler circuit which is formed by the half-wave rectifiers and 67 of the two vacuum tubes til.

The anode of one of the half-wave rectifiers is connected to the cathodes of the tubes 6! and 63 and to an electrolytic capacitor I08 which is connected to one of the alternating current conductors I4. The cathode of the diode 65 is connected to the anode of the other diode 6i and to the other alternating current conductor. The cathode of the diode 67 is connected to the conductor I96. Another electrolytic capacitor I I8 is connected between the conductor I66 and one of the alternating current conductors M. The common juncture between the capacitors I98 and IIil supplies the intermediate direct current voltage to the screen grids of the tetrode portions 6i and 63 of the vacuum tubes 69.

The oscillator circuits are of the balancedgrid-balanced-plate push-pull excitation type whereby the grid circuits are energized or excited from intermediate taps Ill. and I14 on either side of the mid-point of that portion of the tank circuit inductor extending between the anodes of the vacuum tube portions 6| and 63. The control grid of the vacuum tube 6I is provided with a grid resistor I I6 which is connected to its cathode. A grid coupling capacitor I IS interconnects the grid of the vacuum tube 6| with the tap I I2 on the inductor I90. The grid of the vacuum tube 63 is provided with a similarly connected grid resistor I29 and is coupled by a capacitor I22 to the tap I I4 on the tank circuit inductor I00.

The other sealed compartment 52 contains a similarly arranged push-pull oscillator where the screen grids of the tetrode portions of the vacuum tubes 69 and II are connected to each other and to one of the alternating current conductors M. A by-pass capacitor I25 interconnects the cathodes and the screen grids of the tetrode vacuum tubes 68 and 69. The anodes of the vacuum tubes 69 and II are connected to a tank circuit inductor I 24 which has its extremities coupled by isolating capacitors I 26 and I 28 to the conductors I6 and I8 respectively. The anodes of the vacuum tubes II and 69 are connected to one extremity and to an intermediate point on the tank circuit inductor I24. The mid-point of that portion of the tank circuit inductor I24 extending between the anodes of the vacuum tubes 69 and I! is connected to a conductorliid which is connected to one side of the voltage doubling circuit. The grids of vacuum tubes 69 and II are provided with grid resistors I92 and I39 respectively which are connected to their cathodes. The grid of the vacuum tube 69 is coupled by a capacitor I36 to the tap I38 of the tank circuit inductor I24.

The grid of the other Vacuum tube II is coupled to the tap I40 on the tank circuit inductor I24 by a coupling capacitor I42. The anode of the diode rectifier I3 is connected to the oathodes of vacuum tubes 69 and II, and its cathode is connected to the anode of the other diode I5. The one alternating current conductor 14 is connected to the cathode of diode I3 and the anode of diode 15. The cathode of the diode I5 is connected to the conductor I30 and to a capacitor I44 which is connected to the other alternating current conductor I4. A similar capacitor I46 is connected between the one alternating current conductor I4 and the anode of diode 13. The common juncture between the capacitors I44 and I46 is connected to the screen grids of the vacuum tubes 69 and II.

The socket 42 is adapted to receive a suitable local ultraviolet ray applicator which has been shown in the figure as having a handle I48 which supports a gaseous discharge tube I50. The tube I50 has at its lower extremity a bulbous portion I52 provided with an external capacitor type of electrode I54 which is connected to one of the conductors which is connected by a conductor I56 to one of the contacts of the socket 42. Another conductor I58 extends from the socket 42 into the handle I48 to a point in the proximity of the lower bulbous portion I52 of the local applicator discharge tube I50.

The selector switch 56 is provided with three portions A, B, and C. The portion A supplies radio frequency energy from the two push-pull oscillators to both of the

gaseous discharge tubes

34 and 36. The position B supplies radio frequency energy to only the gaseous discharge tube 36. The position C supplies radio frequency energy to only the socket 42. Any suitable type of selector mechanism may be employed, but it has been convenient to illustrate the switching operation by showing a switch which has four movable contacts I60, I62, I64, and I66. The contact arm I60 is connected to the conductor 16 and the contact arm I62 is connected to the conductor 82. The contact arm I64 is connected to the conductor 80 and the contact I66 is connected to the conductor 78. From this it will be seen that the contact arms I60 and I66 are connected to the output circuit of the oscillator contained within the sealed compartment 52 and the other two contact arms are connected to the other oscillator contained Within the sealed compartment 50. The half-wave rectifiers in each of the oscillators are connected so as to supply direct current voltage of approximately two hundred volts to the anodes of the oscillator tubes. The screen grids being connected to the junction of the filter capacitors are supplied with approximately one hundred volts. The oscillators operate at a frequency corresponding to the authorized frequency as defined by the Federal Communications Commission which is in the proximity of thirty megacycles. The selector switch 56 which is in close proximity to both of the oscillators and both of the gaseous discharge devices and the socket from the local applicator provides a compact arrangement whereby the energization of one or all of the devices may be controlled without mis-matching of the oscillator nor the necessity of tuning the matching devices employed in com'unction with a transmission line.

The chassis which is located on top of the radiant energy reflector is relatively compact as is apparent from Figures 2 and 3 which shows the

vacuum tubes

60 and 68 mounted on their sides. This compactness together with the type of structure shown in Figure 1 provides a professional type of ultraviolet ray generator which has flexibility and utility and yet is comparatively economical to manufacture.

While for the purpose of describing and illustrating the present invention, a preferred embodiment has been illustrated in the drawings, it is to be understood that such disclosure is not deemed to be a limitation of the invention since such modifications or variations in the circuit arrangement and in the instrumentalities employed are contemplated as may be commensurate with the spirit and scope of the invention set forth in the following claim.

This invention is hereby claimed as follows:

A radio frequency oscillator for energizing an electrodeless gaseous discharge tube comprising a pair of space discharge tubes each having a pair of diode rectifying electrodes, an anode, a control grid and a cathode, said diode electrodes of each tube including a rectifying cathode and a rectifying anode, the rectifying anode of one tube being connected in series with a condenser to one terminal of an alternating current input circuit to which terminal the rectifying cathode of the other tube is connected in series with a condenser, the remaining rectifying anode and rectifying cathode of the tubes being connected in common to the other terminal of the alternating current input circuit, the cathodes of the tubes being connected in multiple to one of the rectifying anodes, a tank circuit inductor, the anodes of the tubes being connected in pushpull to said inductor, one of said anodes at one end and the other of said anodes spaced from the opposite end of said inductor, a point on said inductor at zero radio frequency potential being connected to one of the rectifying cathodes, each control grid being connected to its cathode through a grid resistor and to points on said inductor through a series grid condenser, an output circuit from said inductor comprising a pair of leads having series condensers and adapted to be connected to opposite ends of said gaseous discharge tube.

FRANK FUREY. CARL E. ATKINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,966,616 David July 17, 1934 1,972,279 Tarzian Sept. 4, 1934 2,034,388 Cemach Mar. 17, 1936 2,072,278 Schade Mar. 2, 1937 2,189,279 Bitner Feb. 6, 1940 2,324,525 Mittelmann July 20, 1943 2,327,346 Furedy Aug. 24, 1943 2,350,462 Johns June 6, 1946 2,439,787 Atkins Apr. 20, 1948