Oil diffusion pump and oil vapor generator used therefor

Abstract

Provided is an oil diffusion pump equipped with an oil vapor generator capable of eliminating a problem that arises when a heater wire is used as a heating source for a hydraulic oil. The oil diffusion pump is a vacuum pump in which an oil vapor generator ( 70 ) is arranged in a casing ( 51 ) and operated to vaporize a hydraulic oil ( 8 ) and produce oil vapor, and this oil vapor is sprayed from a jet ( 53, 53 a) to exhaust an intake air. The oil vapor generator ( 70 ) comprises a tubular case ( 71 ) (object to be heated) extending in an upright direction, an induction coil ( 75 ) wound around the tubular member ( 71 ) via an insulating material ( 73 ), and a power supply means for applying an alternating current to the induction coil ( 75 ). The case ( 71 ) and the coil ( 75 ) are installed in the casing so as to be immersed in the hydraulic oil ( 8 ) stored in the casing ( 51 ). The power supply means is operated to apply an alternating current to the induction coil ( 75 ) to heat the case ( 71 ) itself and thus vaporize the hydraulic oil ( 8 ).

1 . An oil diffusion pump, configured that an oil vapor generator is arranged in a jet provided in a casing, the oil vapor generator is operated to heat a hydraulic oil to produce oil vapor, and the oil vapor in the jet is sprayed from the jet to exhaust an intake air in a high vacuum, wherein:
 the oil vapor generator comprises
 an object to be heated, 
 an induction coil arranged near the object to be heated in an electrically insulated way, and 
 a power supply means for applying an alternating current to the induction coil; 
   wherein the object to be heated and induction coil are installed in the casing such that a part or all thereof is immersed in the hydraulic oil stored in the casing; and   the power supply means is operated to heat the object to be heated and vaporize the hydraulic oil.   
     
     
         2 . The oil diffusion pump according to  claim 1 , wherein the object to be heated in the oil vapor generator is tubular and extending in an upright direction, and an induction coil is wound around the tubular object to be heated via an insulating material provided therebetween. 
     
     
         3 . The oil diffusion pump according to  claim 1 , wherein an object to be heated in the oil vapor generator has a plate shape, and an induction coil is arranged around the plate-shaped object to be heated via an insulating material provided therebetween 
     
     
         4 . The oil diffusion pump according to  claim 1 , wherein a flow path for a hydraulic oil is provided in the casing. 
     
     
         5 . The oil diffusion pump according to  claim 1 , wherein a heating source is not provided on an atmosphere-side bottom portion of the casing. 
     
     
         6 . The oil diffusion pump according to  claim 1 , configured to thermally insulate between the oil vapor generator arranged in the casing and a bottom surface of the casing. 
     
     
         7 . The oil diffusion pump according to  claim 1 , wherein the induction coil is formed by a heat-resistant electric wire covered with an insulator. 
     
     
         8 . A vacuum device comprising an exhaust device for evacuating inside a vacuum container, wherein the oil diffusion pump according to  claim 1  is used as the exhaust device. 
     
     
         9 . An oil vapor generator for heating a hydraulic oil to produce oil vapor in an oil diffusion pump comprising a casing and a jet, installed and used in the casing in the oil diffusion pump, comprising:
 an object to be heated provided in the jet such that a part or all thereof is immersed in the hydraulic oil stored in the casing,   an induction coil provided near the object to be heated in an electrically insulated way such that a part or all thereof is immersed in the hydraulic oil stored in the casing, and   a power supply means for applying an alternating current to the induction coil; and   configured to heat the object to be heated by operating the power supply means and thus vaporize the hydraulic oil.   
     
     
         10 . The oil diffusion pump according to  claim 2 , wherein a flow path for a hydraulic oil is provided in the casing. 
     
     
         11 . The oil diffusion pump according to  claim 3 , wherein a flow path for a hydraulic oil is provided in the casing. 
     
     
         12 . The oil diffusion pump according to  claim 2 , wherein a heating source is not provided on an atmosphere-side bottom portion of the casing. 
     
     
         13 . The oil diffusion pump according to  claim 3 , wherein a heating source is not provided on an atmosphere-side bottom portion of the casing. 
     
     
         14 . The oil diffusion pump according to  claim 4 , wherein a heating source is not provided on an atmosphere-side bottom portion of the casing. 
     
     
         15 . The oil diffusion pump according to  claim 2 , configured to thermally insulate between the oil vapor generator arranged in the casing and a bottom surface of the casing. 
     
     
         16 . The oil diffusion pump according to  claim 3 , configured to thermally insulate between the oil vapor generator arranged in the casing and a bottom surface of the casing. 
     
     
         17 . The oil diffusion pump according to  claim 4 , configured to thermally insulate between the oil vapor generator arranged in the casing and a bottom surface of the casing. 
     
     
         18 . The oil diffusion pump according to  claim 2 , wherein the induction coil is formed by a heat-resistant electric wire covered with an insulator. 
     
     
         19 . The oil diffusion pump according to  claim 3 , wherein the induction coil is formed by a heat-resistant electric wire covered with an insulator. 
     
     
         20 . The oil diffusion pump according to  claim 4 , wherein the induction coil is formed by a heat-resistant electric wire covered with an insulator.