What is the piston?
The piston is the mobile wall which is in the car cylinder.
under the influence of pressure (liquid, steam or gas) moves, setting the parts of the mechanism connected to it in motion. Sometimes (in pumps) the piston, is set in motion by external force by means of the core (a piston rod) strengthened by one end in the middle of the piston, to others — the cylinder coming through a cover to light. Serially increasing or reducing volume one other part of the cylinder on both sides of it, it sucks in this way in the cylinder and then pushes out from it water, air (in pumps), steam, gas mixtures (in engines) and other.
That the piston did not pass liquid or gas from one part of the cylinder in another, it is densely driven to cylinder walls by means of so-called stuffing which becomes or on cylinder walls (the piston skalchaty, differently a plunger, dived) or is more often on the piston (the disk piston) from a tree, hemp, skin or elastic metal rings.
the Piston can be divided into three parts performing different functions: the bottom, the condensing part and the directing part.