METHOD AND A DEVICE FOR CHANGING THE COMPRESSION RATIO OF A RECIPROCATING COMPRESSOR

A device and method are used for changing the compression ratio of a reciprocating compressor. The device includes compression chambers pneumatically connected between an inlet and an outlet port. Communication valves change the number of compression steps and are arranged to switch from a first to a second open/closed state combination, or vice-versa. A lower number and a higher number, and vice-versa, respectively, of the compression chambers include chambers serially connected to one another, so that a gas is subjected to a number of compression steps that increases when switching from the first to the second combination and decreases when switching in the opposite direction. A control unit receives pressure signals upstream and downstream of the reciprocating compressor, respectively, to compute the corresponding pressure ratios, to generate opening/closing control signals responsive to the pressure ratios, and to transfer the control signals to actuators of the commutation valves.