Pressure type flow rate control apparatus
US5816285A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 11, 1997 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Aug 11, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/7761
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A pressure type flow rate control apparatus (1) controls flow rate of a fluid in an environment where a ratio of P2/P1 between an absolute pressure P1 at an upstream side of an orifice and an absolute pressure P2 at a downstream side of the orifice is maintained at a value less than about 0.7. The apparatus comprises: a plate for forming the orifice (5); a control valve (2) positioned upstream of the orifice; an orifice corresponding valve (9) positioned downstream of the orifice (5); a primary pressure detector (3) positioned between the control valve (2) and the orifice (5); a secondary pressure detector (11) positioned downstream of the orifice (5); a calculation control device (6) for calculating flow rate Qc on the basis of the measured pressure P1 of the primary pressure detector (3) by a formula Qc=KP1 (K being a constant) and for outputting as a control signal Qy a difference between a flow rate command signal Qs and the calculated flow rate signal Qc to a drive unit (14) of the control valve 2; and a pressure comparing, calculating apparatus (10) for calculating the ratio of P2/P1 between the detected pressure P1 of the primary pressure detector (3) and the detected pressu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.