what is a free floating piston in reciprocating compressors. what are the advantages of these pistons?

Answer 1

A floating piston does not have a crankshaft....

I can think of a couple of applications where a floating piston is already in use.

1.) Hydraulic accumulator where the piston seperates the hydraulic oil from an inert gas. THis allows an incompressable fluid to store energy (pressure) by compressing a gas.

2.) Air amplifier, basically two pistons connected together by a straight rod. . One piston is larger in diameter than the other. This device is basically an air operated compressor which uses the mechanical advantage of a larger surface ares to compress a smaller volumn of air to a high pressure.

This is most likely what you are referring to as an air compressor.

A free piston engine would not have a crank shaft and would be able to have a very long stroke. There would be less weight in the engine as the crank shaft and connecting rods would be replaced by fluid or compressed gas as in the air amp example.


The link shows an free floating piston engine which illustrates the lack of crank shaft and connecting rods

Answer 2

It is piston which uses the compressed gas to float the piston clear of the walls of the cylinder by allowing a portion of the gas to exit along the walls instead of using piston rings or a tightly machined fit to guide the piston. As a result there is less friction loss and less wear on the piston and cylinder.