Reciprocating compressor with double headed pistons

A reciprocating compressor comprising:

• a housing having an axis, a front and a rear cylinder block having a plurality of pairs of cylinder bores arranged around the axis with each pair including coaxially extending front and rear cylinder bores, a crank chamber formed between said front and rear cylinder blocks, and a tapered valve chamber formed in the cylinder blocks on either side of the crank chamber along the axis, the tapered valve chambers having conical inner surfaces with larger and smaller diameter ends;
• double headed pistons arranged in the respective pairs of cylinder bores to form compression chambers at either head of the pistons;
• a drive shaft inserted in the crank chamber and the valve chambers and rotatably supported by the housing;
• a cam plate arranged in the crank chamber and fixed to the drive shaft to engage with the pistons for reciprocatingly moving the pistons;
• a pair of tapered rotary valves arranged in the valve chambers and supported by the drive shaft so that each rotary valve can rotate with the drive shaft and can move axially relative to the drive shaft, the rotary valves having conical outer surfaces to make surface-contact with the conical inner surfaces of the valve chambers;
• the rotary valves having suction passages for introducing a coolant gas into the compression chambers during suction strokes;
• first urging means for urging each of the rotary valves into contact with the conical inner surface of the associated valve chamber;
• second urging means for urging the drive shaft in an axially predetermined direction;
• and
• means for controlling the movements of the rotary valves away from the valve chambers caused by a pressure in the compression chambers when the pressure in the compression chambers becomes higher than the compression pressure during normal operation of the compressor so that a compression reaction force acting on the drive shaft via the pistons and the cam plate occurs in said axially predetermined direction.