The first pump used for the creation of a vacuum (pneumatic pump), designed by Otto von Guericke (1602-1686) in 1650, and the one derived from it, which continued to be used for a long time, are piston pumps (suction and compression) quite similar to those used for liquids.
Briefly, they are composed of a cylinder, called the pump body, which at the bottom communicates with the recipient in which the vacuum is to be created through a valve that opens only from below to above.
A piston travels inside the pump body. It has a sealing gasket consisting of greased leather and a valve which, on opening, it too from below to above, places in communication the pump body with the outside.
When the piston is raised, the air that inevitably remains in the space between the base of the piston and the base of the pump body and between the edge of the piston and the walls (clearance volume) undergoes an expansion. The piston valve remains closed while that of the pump body, pushed upwards by the pressure of the air contained in the recipient in which the vacuum is being created, opens.
On lowering the piston, the air, which from the recipient has entered the pump body, is compressed, the valve of communication with the recipient closes and, as soon as atmospheric pressure has been exceeded the piston valve opens and it escapes to the outside. ...continues