Orbiting Piston Machines

Abstract

The casing ( 1 ) of a positive displacement machine has a cylindrical internal surface ( 3 ) delimiting an operating chamber which accommodates an orbiting piston ( 4 ) having a cylindrical external surface. At least one of the said surfaces, e.g. the internal surface ( 3 ), is at least partly constituted by a peripheral wall ( 2 ) having a front surface facing the operating chamber and a rear surface. The peripheral wall ( 2 ) having through-slots ( 22 ) which extend parallel to one another and accommodate respective compliant strips ( 24 ) extending from the front surface to the rear surface. The strips ( 22 ) are retained in the slots ( 22 ), against pressure in the operating chamber, by a retaining device such as a clamping member ( 28 ). An assembly of three positive displacement machines and engines comprising first and second positive displacement machines are also described.

1 . A rotary positive displacement machine comprising:
 a casing having a cylindrical internal surface delimiting an operating chamber; and   an orbiting piston in the operating chamber, having a cylindrical external surface;   wherein at least one of the said external and internal surfaces is at least partly constituted by a peripheral wall having a front surface facing the operating chamber and a rear surface, the peripheral wall having through-slots which extend parallel to one another, the through-slots accommodating respective compliant strips extending from the front surface to the rear surface, retaining means being provided to retain the strips in the slots against pressure in the operating chamber.   
   
   
       2 . A machine as claimed in  claim 1 , in which the compliant strips are connected to one another by a ribbon at the rear surface. 
   
   
       3 . A machine as claimed in  claim 1 , in which the retaining means comprises a peripheral clamp cooperating with the rear surface of the peripheral wall. 
   
   
       4 . A machine as claimed in  claim 1 , in which the casing is provided with the said compliant strips. 
   
   
       5 . An assembly comprising three rotary positive displacement machines, each machine comprising a casing having a cylindrical internal surface delimiting an operating chamber and an orbiting piston in the operating chamber, having a cylindrical external surface, the casings being connected together and the orbiting pistons being kinematically linked. 
   
   
       6 . An assembly as claimed in  claim 5 , in which the orbiting pistons are mounted on a common shaft. 
   
   
       7 . An assembly as claimed in  claim 5 , in which at least two of the machines function as compressors. 
   
   
       8 . An assembly as claimed in  claim 7 , in which one of the machines functions as an expander. 
   
   
       9 . An assembly as claimed in  claim 7 , in which all three machines function as compressors and are fluidly interconnected. 
   
   
       10 . An assembly as claimed in  claim 9 , in which two of the machines are fluidly connected in parallel to the third one. 
   
   
       11 . An assembly as claimed in  claim 9 , in which the three machines are fluidly connected in series. 
   
   
       12 . An assembly as claimed in  claim 5 , the assembly being fluidly connected to an internal combustion engine so as to supply compressed air to the engine. 
   
   
       13 . An assembly as claimed in  claim 12 , including valve means for venting air from the assembly in order to control the pressure of the compressed air. 
   
   
       14 . An assembly as claimed in  claim 12 , including heat exchange means for cooling the compressed air. 
   
   
       15 . An engine comprising:
 a first positive displacement machine;   a second positive displacement machine;   an inlet duct connected to the first positive displacement machine;   an intermediate duct connected between the first and second positive displacement machines;   an outlet duct connected to the second positive displacement machine;   a heater for raising the temperature and pressure of a gaseous working fluid in the intermediate duct; and   a kinematic connection between the first and second positive displacement machines;   the arrangement being such that, in operation of the engine, the first positive displacement machine causes the working fluid to flow through the intermediate duct to the second positive displacement machine, the heated working fluid drives the second positive displacement machine, and the second positive displacement machine drives the first positive displacement machine via the kinematic connection;   the engine further comprising a heat pump circuit through which a refrigerant flows, including, in sequence, a compressor, a condenser which constitutes at least part of the said heater, an expander, and an evaporator;   wherein the heat pump circuit includes means for supplying heat to the refrigerant between the evaporator and the compressor.   
   
   
       16 . An engine as claimed in  claim 15 , in which the said means comprises a heat exchanger through which pass a refrigerant-carrying first line, connecting the evaporator and the compressor, and a refrigerant-carrying second line, connecting the condenser and the expander. 
   
   
       17 . An engine as claimed in  claim 16 , further comprising a valve for by-passing the said heat exchanger in the second line. 
   
   
       18 . An engine as claimed in  claim 15 , in which the said means comprises a heat exchanger through which pass a refrigerant-carrying first line, connecting the evaporator and the compressor, and a second line carrying working fluid from the second positive displacement machine. 
   
   
       19 . An engine as claimed in  claim 15 , in which a refrigerant-carrying line connecting the condenser and the expander passes through a heat exchanger.