Abstract: An unloader system is provided for a reciprocating gas compressor. The system includes an unloader valve assembly including a valve member controlling flow between compressor cylinder and a clearance bottle. Opening and closing of the valve member is controlled by manipulating a control pressure acting through a manifold against the stem of the valve member by means of a pressure regulator connected in series with a pressure source. When the pressure in the compressor cylinder acting on the heads of the poppet valve members exceeds the control pressure acting on the stems, the poppet valve members open, partially unloading the compressor.

Abstract: An unloader system is provided for a reciprocating gas compressor. The system includes an unloader valve assembly including a valve member controlling flow between compressor cylinder and a clearance bottle. Opening and closing of the valve member is controlled by manipulating a control pressure acting through a manifold against the stem of the valve member by means of a pressure regulator connected in series with a pressure source. When the pressure in the compressor cylinder acting on the heads of the poppet valve members exceeds the control pressure acting on the stems, the poppet valve members open, partially unloading the compressor.

Abstract: An unloader system is provided for a reciprocating gas compressor having a cylinder, a piston reciprocably mounted in the cylinder, a rotatable crankshaft connected to the piston, a suction valve assembly, and a discharge valve assembly for selectively communicating suction and discharge lines with the compressor cylinder. An unloader valve assembly including a valve seat structure, valve guard, and multiple poppet valve members is provided to allow selective communication between the compressor cylinder and a clearance bottle. The opening and closing of the unloader valve assembly is controlled by manipulating a control pressure acting through a manifold against the stem ends of the poppet valve members by means of a pressure regulator connected in series with a pressure source. When the pressure in the compressor cylinder acting on the heads of the poppet valve members exceeds the control pressure acting on the stems, the poppet valve members open, partially unloading the compressor.