Free-piston compressor has spring loaded piston to shut outlet - before end of stroke, the moment of shutting being function of working conditions

摘要

The compressor is of the type in which a non-mechanically driven piston is caused to reciprocate freely by impulses acting on it, thereby taking in and compressing gas in a cylinder provided with inlet and outlet valves, the outlet port being shut before the end of the stroke so that a gas buffer is created which has an effect on the working conditions. Means are provided which determine the volume of this buffer at the moment the outlet port is shut as a function of at least one working condition. Preferably a spring-loaded auxiliary piston is provided of which one side is exposed to the inlet pressure and the other side to the discharge pressure, and which projects from the main piston into the compressor chamber by an amount determined by the pressure differential across it, the arrangement being such that its projecting portion closes the outlet orifice.