System for controlling flow through a process region
US5655562A · kind A · utility
Inventor
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Aug 12, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/5907
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A regulator for maintaining a constant partial vacuum in a region, such as in a piece of process equipment or a fume hood. The regulator includes a path, through which fluid passes from the region to the vacuum source, and a movably mounted piston. The piston is disposed in the path so that the piston may constrict the path at a constriction point. Fluid in the path upstream of the constriction point exerts a pressure on the frontal face of the piston that tends widen the path at the constriction point. The piston is mounted so that the weight of the piston exerts a force on the piston in a direction that tends to widen the path at the constriction point. A force is exerted on the piston, preferably by a spring under compression, in a direction that tends to narrow the path at the constriction point. A buffering gas, introduced to the area between the piston's skirt and the piston mounting structure, may be used to keep noxious fumes from backing up into the environment and/or to provide an efficient bearing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.