Rotary Expander

Abstract

The upper and lower end surfaces ( 67 b , 67 c ) of a rotary piston ( 67 ) are formed with annular seal grooves ( 91 ) extending along the annular end surfaces ( 67 b , 67 c ), and an annular lip seal ( 92 ) is fitted in each of the seal grooves ( 91 ). Thereby, the lubricating oil fed from oil feed grooves ( 49 ) in the shaft ( 40 ) rarely flows from between the upper and lower end surfaces ( 67 b , 67 c ) of the rotary piston ( 67 ) and front and rear heads ( 61, 62 ) and into the fluid chamber ( 65 ) of a cylinder ( 63 ), so that shortage of lubricating oil is eliminated.

1 . A rotary expander comprising an expansion mechanism ( 60 ) that includes a cylinder ( 63 ) closed at both ends by closing members ( 61 ,  62 ) and a rotary piston ( 67 ) placed in the cylinder ( 63 ),
 wherein at lease one of the end surfaces of the rotary piston ( 67 ) is provided with a sealing mechanism ( 90 ) for sealing the end surfaces with respect to the closing members ( 61 ,  62 ).   
   
   
       2 . The rotary expander of  claim 1 , further comprising
 a single rotary shaft ( 40 ) having an eccentric part ( 41 ) rotatably fitted in the rotary piston ( 67 ); and   said rotary shaft ( 40 ) being formed with an oil feeding channel ( 49 ) for feeding lubricating oil to at least sliding areas formed by the eccentric part ( 41 ) and the closing members ( 61 ,  62 ) and a sliding area between the rotary piston ( 67 ) and the eccentric part ( 41 ).   
   
   
       3 . The rotary expander of  claim 2 , wherein
 the expansion mechanism ( 60 ) includes a plurality of rotary pistons ( 75 ,  85 ),   the rotary pistons ( 75 ,  85 ) are connected to each other through the single rotary shaft ( 40 ) and juxtaposed so that the adjacent end surfaces of the rotary pistons ( 75 ,  85 ) face each other with an intermediate partition plate ( 64 ) interposed therebetween, and   out of the end surfaces of the plurality of rotary pistons ( 75 ,  85 ), the end surfaces facing the closing members ( 61 ,  62 ) are individually provided with the sealing mechanisms ( 90 ).   
   
   
       4 . The rotary expander of any one of  claims 1  to  3 , wherein the sealing mechanism ( 90 ) is constituted by a sealing groove ( 91 ) formed in the end surface of the rotary piston ( 67 ) and a sealing member ( 92 ) fitted in the sealing groove ( 91 ). 
   
   
       5 . The rotary expander of  claim 4 , wherein the sealing member ( 92 ) is a lip seal or a chip seal. 
   
   
       6 . The rotary expander of any one of  claims 1  to  3 , wherein the sealing mechanism ( 90 ) is a labyrinth seal. 
   
   
       7 . The rotary expander of  claim 4 , wherein the sealing member ( 92 ) is made of ethylene tetrafluoride-based resin material. 
   
   
       8 . The rotary expander of  claim 1 , wherein the fit tolerance of the rotary piston ( 67 ) in the axial direction of the rotary shaft ( 40 ) is set at a size of 1/5000 to 1/1000 of the inner diameter D of the cylinder ( 63 ).