A reciprocating atmosphere compressor is a positive displacement compressor that uses a crankshaft-driven piston and cylinder to compress the air flow. … A two-stage compressor contains an additional step where in fact the atmosphere is compressed by Piston Air Compressor another, smaller sized piston to a pressure as high as 175 PSI.

Like a small internal combustion engine, a typical piston compressor has a crankshaft, a connecting rod and piston, a cylinder and a valve head. … As the piston moves down, a vacuum is created above it. This allows outside atmosphere at atmospheric pressure to force open the inlet valve and fill the area above the piston.