Piston pump with zero to negative clearance valve
US6190143A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 1999 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | Oct 18, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04B39/08
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An improved piston-type vacuum pump comprises a reciprocating piston disposed within a cylinder having a proximal end and a distal end, an inlet port formed in the side of the cylinder near the proximal end, and a spring-biased outlet valve, such as a poppet valve or a rocker valve, disposed at the distal end of the cylinder. The piston stroke is configured to provide zero or negative clearance between the piston head and the face of the outlet valve at the end of the compression stroke. The piston reciprocates within the cylinder from a first position wherein the surface of the piston head is proximal of the inlet port, to a second position wherein the surface of the piston head is beyond the distal end of the cylinder, so as to contact the face of the outlet valve in its open position. The piston top and outlet valve face remain in contact until the piston has retracted into the distal end of the cylinder, allowing the valve to seal the distal end of the cylinder prior to the beginning of the expansion stroke, such that there is substantially no dead volume within the cylinder at the beginning of the expansion stroke.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.