Helical coil for diathermy apparatus
First Claim
1. A diathermy apparatus comprising elongated hollow support means adapted to receive dielectric material to be heated, a coil surrounding said elongated support means substantially coaxially and comprising a plurality of turns, radio frequency generator means providing an output frequency in the range of from 7.5 MHz to 62 MHz, and means for connecting the output of said generator means to said coil, only the coil and the contents of said hollow support means acting as a load, the total wire length of said coil being about 0.7 to 1.3 times the fundamental wavelength corresponding to said output frequency.
1 Assignment
0 Petitions
Accused Products
Abstract
A deep-heating diathermy apparatus consisting of a hollow tube adapted to receive a part of the body, or other dielectric material to be treated. An rf coil coaxially surrounds the tube and is driven by an rf generator. The total wire length of the coil is approximately 0.7 to 1.3 (depending on specific electrical properties and volume of the treated material) times the wavelength of a basic driving frequency provided by the generator. The output of the generator is supplied to the coil via a 50-ohm coaxial cable and a matching impedance. The coil may be driven by frequencies corresponding to integral multiples of one-half the basic wavelength, to enable shifting the heat focus volume along the coil axis from the normal centered location on the axis produced by full-wave excitation.
199 Citations
14 Claims
- 1. A diathermy apparatus comprising elongated hollow support means adapted to receive dielectric material to be heated, a coil surrounding said elongated support means substantially coaxially and comprising a plurality of turns, radio frequency generator means providing an output frequency in the range of from 7.5 MHz to 62 MHz, and means for connecting the output of said generator means to said coil, only the coil and the contents of said hollow support means acting as a load, the total wire length of said coil being about 0.7 to 1.3 times the fundamental wavelength corresponding to said output frequency.
-
12. Apparatus for providing axially focussed, uniform deep heating for a portion of a body, such as a limb, comprising:
-
hollow support means for supporting said body portion; a coil surrounding, and supported by, said support means; radio frequency generator means providing an output frequency of between 7.5 MHz and 62 MHz; and means for connecting the output of said generator means to said coil, only the coil and the contents of said hollow support means acting as a load, the total length of said coil wire being 0.7 to 1.3 times the fundamental wavelength of the output frequency so that heat is focussed along the axis of the coil.
-
- 13. A method of heating a dielectric material comprising inserting the material in a coil and energizing said coil with current at a radio frequency in the range of from 7.5 MHz to 62 MHz, the coil having a wire length about 0.7 to 1.3 times that of the wavelength of said radio frequency, whereby to develop heat in said material at a first location along the axis of the coil, and modifying the axial distribution of the developed heat by energizing the coil with a radio frequency current corresponding to an integral multiple of a half-wavelength of said first-named wavelength.
Specification