Ultrasonic leak detection system

US5710377A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Robert C. Youngquist · Cocoa, US
• J. Steven Moerk · Taylorsville, US

Key dates

• Filing date: Oct 17, 1995
• Grant date: Jan 20, 1998
• Expiry date: Oct 17, 2015

Classification

• Technology area (CPC G): Physics
• CPC primary: G01V1/001
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A system for detecting ultrasonic vibrations, such as those generated by a small leak in a pressurized container, vessel, pipe, or the like, comprises an ultrasonic transducer assembly and a processing circuit for converting transducer signals into an audio frequency range signal. The audio frequency range signal can be used to drive a pair of headphones worn by an operator. A diode rectifier based mixing circuit provides a simple, inexpensive way to mix the transducer signal with a square wave signal generated by an oscillator, and thereby generate the audio frequency signal. The sensitivity of the system is greatly increased through proper selection and matching of the system components, and the use of noise rejection filters and elements. In addition, a parabolic collecting horn is preferably employed which is mounted on the transducer assembly housing. The collecting horn increases sensitivity of the system by amplifying the received signals, and provides directionality which facilitates easier location of an ultrasonic vibration source.