Volumetric pump and its driving mechanism

A volumetric pump comprising a housing containing at least one hollow elongated part, at least one piston arranged to move back and forth inside said elongated part, at least one inlet port and at least one outlet arranged so that a fluid can be sucked through the inlet port into a piston chamber during an instroke of the piston and expelled from the piston chamber through an outlet port during an outstroke of said piston, the housing comprising at least one through-hole extending from the piston chamber to a housing outer surface, the volumetric pump further comprising a linearly and/or angularly actuable valve system having at least one valve holder mounted on the pump housing outer surface against a lateral side of the pump housing such that a part of the at least one valve holder is held against a corresponding part of said lateral side, said at least one valve holder comprising at least one inlet and/or outlet aperture and being arranged to be linearly and/or rotatably actuable to align alternately the inlet and outlet apertures with the through-hole of the housing in order to connect alternately the inlet and outlet ports of the volumetric pump with the piston chamber during alternate piston instrokes and outstrokes, wherein the at least one valve holder of the valve system comprises the inlet and outlet ports of the volumetric pump such that said inlet and/or outlet port are linearly and/or rotatably actuable along with the valve holder, the volumetric pump further comprising a driving mechanism comprising a crankshaft possessing an eccentric shaft arranged upon rotation of the crankshaft to impart a to-and-fro linear movement to the valve system;

• wherein the at least one valve holder comprises a first valve holder called an inlet valve holder slidably mounted along a longitudinally-extending lateral side of the housing, and a second valve holder called an outlet valve holder slidably mounted along another longitudinally-extending lateral side of the housing, wherein the inlet valve holder comprises the said at least one inlet aperture arranged to be aligned with one inlet through-hole of the housing in order to connect the piston chamber with the inlet port during the instroke of the piston;
• and wherein the outlet valve holder comprises the said at least one outlet aperture arranged to be aligned with an outlet through-hole of the housing in order to connect the piston chamber with the outlet port during the outstroke of the piston.