System for controlling flow through a process region
US5450873A · kind A · utility
Inventor
Key dates
| Filing date | Oct 22, 1993 |
| Grant date | Sep 19, 1995 |
| Priority date | — |
| Expiry date | Oct 22, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87676
- 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 having a frontal face, which is exposed to fluid in the path, and a distal face, which is exposed to a reference pressure, such as the pressure of the environment in which the equipment is located. 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 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.