System for comparing a reference signal with a filtered signal to detect pressure discontinuity

US5349864A · kind A · utility

Assignee

• KAVLICO CORPORATION · US

Inventors

• Kyong M. Park · Thousand Oaks, US
• Niraj Gupta · Faridabad, IN

Key dates

• Filing date: Jul 7, 1993
• Grant date: Sep 27, 1994
• Expiry date: Jul 7, 2013

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L9/12
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A simple, reliable, compact and inexpensive fluid pressure discontinuity analysis system includes a basic capacitive pressure transducer, made of two closely spaced insulating plates whose opposed faces contain conductive layers, and one of which plates is a flexible diaphragm of low mechanical hysteresis. The transducer is coupled to a variable pressure source which under normal operating conditions remains at a substantially constant pressure level. The output signal from the transducer has its high-frequency AC component attenuated by a low-pass filter, whose output in turn has its DC component substantially removed by capacitive blocking, after which the remaining AC output is then amplified by a circuit including an operational amplifier. This AC-amplified signal is then compared with a "reduced-magnitude average" reference signal (produced by an AC-to-DC conversion side-circuit followed by magnitude-level adjustment). The comparator output triggers a one-shot monostable multivibrator used to produce an on-off switching signal which operates an alarm signal.