Temperature measurement arrangement

Abstract

Method of processing objects by radio frequency (RF) energy. The method includes feeding, with a plurality of radiating elements, RF radiation into a cavity to process the objects in the cavity, receiving, with a plurality of dummy loads located outside of the cavity, RE energy coupled from the cavity into the radiating elements, and estimating an effect that operating at each of a plurality of sets of operating parameters will have on the temperature of each of the dummy loads. The method also includes, while maintaining the temperature of the dummy loads within a safe temperature range, choosing among the plurality of sets of operating parameters, at least one set based on the estimating and operating at the chosen at least one set of operating parameters.

What is claimed: 
     
         1 . A method of processing objects by radio frequency (RF) energy, comprising:
 feeding, with a plurality of radiating elements, RF radiation into a cavity to process the objects in the cavity;   receiving, with a plurality of dummy loads located outside of the cavity, RF energy coupled from the cavity into the radiating elements; and   estimating an effect that operating at each of a plurality of sets of operating parameters will have on the temperature of each of the dummy loads;   while maintaining the temperature of the dummy loads within a safe temperature range, choosing among the plurality of sets of operating parameters, at least one set based on the estimating; and   operating at the chosen at least one set of operating parameters.   
     
     
         2 . The method of  claim 1 , wherein the plurality of radiating elements and the plurality of dummy loads are arranged on an RF feeding module. 
     
     
         3 . The method of  claim 1 , wherein at least one of the estimating, the choosing and the operating are performed by a processor. 
     
     
         4 . The method of  claim 3 , wherein the processor estimates the effect by estimating amounts of power, each of which will be returned from the cavity through one of the radiating elements. 
     
     
         5 . The method of  claim 3 , wherein the processor estimates field distributions, each of which will be excited in the cavity at a corresponding one of the plurality of sets of operating parameters, and chooses the at least one set based on the estimation of the field distribution associated with the at least one set and the estimate of the effect of the at least one set on the temperature of each dummy load. 
     
     
         6 . A method of processing objects by radio frequency (RF) energy in a cavity, comprising:
 feeding, with a plurality of radiating elements, RF radiation into the cavity to process the objects in the cavity;   receiving, with a plurality of dummy loads located outside of the cavity, RF energy coupled from the cavity into the radiating elements;   utilizing a processor to:
 estimate an effect that operating the system at each of a plurality of sets of operating parameters will have on the temperature of each of the dummy loads; 
 choose among the plurality of sets of operating parameters, at least one set based on the estimate; and 
 operate at the chosen at least one set of operating parameters; and 
   measuring, with at least one temperature sensing arrangement, temperatures of each of the dummy loads.   
     
     
         7 . The method of  claim 6 , wherein the choosing utilizes a processor and the processor chooses the at least one set of operating parameters based on a measured temperature of each dummy load. 
     
     
         8 . A method of dielectrically processing a product in a radio frequency (RF) cavity, comprising:
 feeding, via an RF feeding module, RF energy into the cavity at various frequencies for processing the product;   receiving, via a dummy load located in an electromagnetically noisy space outside of the cavity, RF energy returning from the cavity; and   measuring a temperature of the dummy load with a temperature sensing arrangement that comprises:
 an RF fitter configured to allow propagation of infrared (IR) radiation through the RF filter and configured so that propagation of various frequencies through the RF filter is decreased by at least 10 dB; and 
 a temperature sensor operative to measure a temperature of an object based on the amount of IR radiation that propagates through the RF filter and arranged with respect to the RF filter to be unaffected by the electromagnetic noise in the electromagnetically noisy space. 
   
     
     
         9 . The method of  claim 8 , further comprising operatively coupling a processor with the RF feeding module and the temperature sensing arrangement in order to enable operating the RF feeding module based on a measured temperature of the dummy load. 
     
     
         10 . The method of  claim 9 , farther comprising programming the processor to operate the RF feeding module based on the temperature of the dummy load as measured by the temperature sensing arrangement. 
     
     
         11 . The method of  claim 8 , wherein the RF filter comprises electrically conductive walls defining an electrically non-conductive core, wherein dimensions of the non-conductive core are such that propagation of frequencies of electromagnetic noise through the core is not supported while the propagation of IR radiation through the core is allowed. 
     
     
         12 . The method of  claim 8 , wherein the temperature sensor is arranged in an EMI free space that is created by an electromagnetic shielding and the EMI-free space and the electromagnetically noisy space are in IR radiation communication with each other via the RF filter. 
     
     
         13 . The method of  claim 8 , wherein the RF filter comprises an RF waveguide having a cutoff frequency above any one of the various frequencies, and a length sufficient to attenuate any one of the various frequencies by at least 10 dB.