GB990080A - Leak detector for pressure and vacuum systems - Google Patents

Leak detector for pressure and vacuum systems

Info

Publication number
GB990080A
GB990080A GB3944162A GB3944162A GB990080A GB 990080 A GB990080 A GB 990080A GB 3944162 A GB3944162 A GB 3944162A GB 3944162 A GB3944162 A GB 3944162A GB 990080 A GB990080 A GB 990080A
Authority
GB
United Kingdom
Prior art keywords
signal
frequency
mixer
oscillator
receiver
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3944162A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Delcon Corp
Original Assignee
Delcon Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Delcon Corp filed Critical Delcon Corp
Publication of GB990080A publication Critical patent/GB990080A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/24—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/24—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations
    • G01M3/243—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using infrasonic, sonic, or ultrasonic vibrations for pipes
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
    • G08B13/1654—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Examining Or Testing Airtightness (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)

Abstract

990, 080. Detecting ultrasonic vibrations. DELCON CORPORATION. Oct. 18, 1962 [Nov. 14, 1961], No. 39441/62. Heading G4F. [Also in Division H4] In a method for detecting leaks in a pressure or vacuum system an ultrasonic transducer is disposed in the vicinity of the system to pick up ultrasonic vibrations emitted by a leak and to generate an electrical signal corresponding to the vibration. This signal is mixed with a further signal which differs from it in frequency by about 3, 000-5, 000 c/s so that a beat signal having a frequency of approximately 3, 000-5, 000 c/s is generated. The beat signal is supplied to a sonic transducer which generates an audible sound corresponding to the beat signal, to indicate the presence of a leak in the pressure or vacuum system. In one embodiment (Fig. 1) the ultrasonic vibrations are detected by means of a transducer 10 which converts them into an electric signal which differs from it in frequency by about 14. The signal then passes through a high pass filter 16, which rejects substantially all frequencies below 15, 000 c/s and then to a mixer 18. The mixer is also supplied from an oscillator 19 which is tuned so that the mixer produces a difference signal in the 3, 000-5, 000 c/s range. The mixer output passes through a low pass filter 20 to an audio amplifier 22 and thence to a push-pull audio output stage terminating in a loudspeaker 26, where an audible tone is produced. In many cases e.g. in a noisy environment, or for checking such as telephone lines enclosed in pressurised conduits, it is desirable to separate the listening and pick up portions of the system, and the apparatus of Fig. 2 may be used. In this system the electrical signal produced by the ultrasonic transducer is used to modulate the output from a crystal controlled high frequency oscillator 40 (producing a signal in the frequency range 2-10 Mc/s). These modulated signals are transmitted from an antenna 44 to a receiving antenna 46. The receiver consists of a conventional single sideband, carrier suppressed receiver 48, designed to receive the lower sideband, and is connected to a loudspeaker 50. This receiver contains an oscillator driven at a frequency just above the lower sideband frequency, so that when the transmitted signal is mixed with the receiver oscillator output, a signal in the audible range is detected.
GB3944162A 1961-11-14 1962-10-18 Leak detector for pressure and vacuum systems Expired GB990080A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15224761A 1961-11-14 1961-11-14

Publications (1)

Publication Number Publication Date
GB990080A true GB990080A (en) 1965-04-22

Family

ID=22542118

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3944162A Expired GB990080A (en) 1961-11-14 1962-10-18 Leak detector for pressure and vacuum systems

Country Status (2)

Country Link
DE (1) DE1473402A1 (en)
GB (1) GB990080A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2269900A (en) * 1992-08-19 1994-02-23 Christopher David Hill Acoustic leak detection method for liquid storage tanks
GB2367126A (en) * 1999-08-14 2002-03-27 Wt Thermo Tec Ltd A method of testing a pressurised vessel for a leak using ultrasonic sensors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2269900A (en) * 1992-08-19 1994-02-23 Christopher David Hill Acoustic leak detection method for liquid storage tanks
GB2367126A (en) * 1999-08-14 2002-03-27 Wt Thermo Tec Ltd A method of testing a pressurised vessel for a leak using ultrasonic sensors

Also Published As

Publication number Publication date
DE1473402A1 (en) 1969-02-06

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