Patent ID: 8337174
Filing Date: 2012-12-25
Classification: F04B

Abstract:
1. A long-life pump unit, comprising at least one pump module comprising a body provided with a cavity constituting a working chamber, a translationally mobile piston engaging leaktightly in the a cavity via a seal arranged between said body and said piston, at least one channel formed in the body so as to be able to connect the working chamber to a use circuit, said body comprising an assembly surface centered perpendicular to the axis of movement of the piston, and a linear actuating module comprising an actuating member translationally mobile coaxially to the piston, a connecting and guiding module for establishing a mechanical connection between the pump module and the linear actuating module and precise guidance of the piston coaxially to the sealing device, this guidance being independent of the guide means used by the linear actuating module, and wherein the coupling between the actuating member and the piston is ensured via the assembly, on one hand, of a cylindrical-spherical seal having a spherical head centered on the axis of the actuating member and connected thereto by an under-head portion with a section smaller than the diameter of the sphere and, on the other hand, a cylindrical groove realized in the end of the piston opposite the pump member, perpendicular to the axis of said piston, this said cylindrical groove opening axially at the outside by a slot with a width smaller than the diameter of the groove and slightly larger than said under-head portion.