Differential pressure measuring system
US4457179A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1981 |
| Grant date | Jul 3, 1984 |
| Priority date | — |
| Expiry date | Mar 16, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A differential pressure measuring system is disclosed. The system includes two quartz capacitive pressure transducers (14, 16). Each capsule contains a pressure sensitive capacitor (Csa, Csb) and a relatively pressure invariable reference capacitor (Cra, Crb). The pressure sensitive capacitors (Csa, Csb) are excited by out-of-phase signals, (Vr, -Vr) which further excite the reference capacitors (Cra, Crb), out of phase, respectively. The outputs of all capacitors are combined in a summing junction (22) whose output controls the count of a digital integrator (34). A closed loop is formed by converting the output of the integrator (34) to a negative feedback signal (lf) which is applied to the summing junction (22) through a feedback capacitor (Cf). The integrator (34) incrementally changes the feedback signal (lf) in a direction to balance the loop. At this point the output of the integrator (34) is representative of the measured differential pressure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.