Ultrasonic gas leak detector including a detector testing device

• US 20060191341A1
• Filed: 07/02/2004
• Published: 08/31/2006
• Est. Priority Date: 10/08/2003
• Status: Active Grant

• Current Assignee: Gassonic A/S
• Original Assignee: Gassonic A/S
• Inventors: Petersen, Kjeld Henning, Olesen, Martin Tranderup
• Granted Patent: US 7,318,335 B2
• Time in Patent Office: Days
• US Class Current: 73/592
• CPC Class Codes: G01M 3/243 for pipes

Abstract

The invention relates to an ultrasonic gas leak detector of the kind where a detector transducer senses airborne acoustic ultrasonic sound waves emitted from a leakage in a gas installation. The detector is provided with self-test means according to which an ultrasonic signal is emitted by a test transducer provided as an integral part of the detector, this signal being received by the detector transducer. By these means an ongoing self-test of the performance of the essential components of the detector, e.g. the detector transducer itself, the various electronic circuits of the detector, etc., can be carried out and an alert signal can for instance be transmitted to a central alarm system if inappropriate performance of the detector is discovered. The detector according to the invention can be specially designed for fixed installation in an explosion-endangered environment.

Claims

1. Ultrasonic gas leak detector device comprising a housing provided with a detector transducer (2) for receiving acoustic broadband noise (S1) generated by a gas leakage and propagating through air, where said housing being designed for use in explosion endangered environments, and where said housing on an external surface hereof being furthermore provided with at least one test transducer (11) for emitting an acoustic signal (S2), which can be received by said detector transducer (2), said device furthermore comprising self-test means by means of which said device is tested ongoing by said acoustic signal (S2) emitted from said at least one test transducer (11), whereby the correct functioning of the complete detector device can be monitored.

2. Device according to claim 1, characterized in that it comprises means for isolating the ultrasonic part of said acoustic broadband noise (S1) for further processing in the device.

3. Device according to claim 1, characterized in that said acoustic signal (S2) emitted from the at least one test transducer (11) is an ultrasonic signal.

4. Device according to claim 1, characterized in that said at least one test transducer (11) emits an acoustic signal (S2) which at said detector transducer (2) gives rise to a sound pressure level, which is not interfering with the ultrasonic background level normally present at the detector transducer (2).

5. Device according to claim 1, characterized by being accommodated in a housing designed for fixed installation.

6. Device according to claim 1, characterized in that the detector is provided with means for analogue and/or digital communication with an external system.

7. Device according to claim 6, characterized in that said external system is a central alarm system.

8. Device according to claim 6, characterized in that said communication means comprise a 4-20 mA Interface, relay output for alarm trigger level setting and error alarm for indication of internal instrument failure.

9. Device according to claim 1, characterized in that it further comprises a digital communications interface.

10. Device according to claim 1, characterized in that said detector device (1) being furthermore provided with self-test means for performing an electronic test of said detector transducer (2) and/or the electronic circuits in the detector device.

12. Ultrasonic gas leak detection system comprising a detector device according to claim 1 and connected to an external system.

13. System according to claim 12, characterized in that said external system is an alarm system being provided with means for eliciting an alarm signal if it is determined that a signal received by the detector transducer (2) is caused by a gas leak, and means for providing an alert signal if it is determined that a signal emitted by the test transducer does not give rise to a corresponding expected signal from the detector.

11. Ultrasonic gas leak detector device comprising a detector transducer (2) for receiving an ultrasonic signal (S1) generated by a gas leakage, characterized in that said device (1) being provided with self-test means for performing an electronic test of said detector transducer (2) and/or the electronic circuits in the detector device, whereby the correct functioning of the main parts of the detector device can be monitored.

14. Ultrasonic gas leak detector self-test method for a detector provided with a detector transducer (2) for receiving an acoustic signal (S1) generated by a gas leakage and a test transducer (11) for emitting an acoustic test signal (S2), said method comprising the following steps:

(a) repetitively emitting a test signal (S2) from said test transducer (11);

(b) receiving said test signal (S2) at said detector transducer (2);

(c) determining whether the sound pressure level of S2 at the detector transducer falls within a given tolerance range;

(d) if said sound pressure level of S2 at the detector transducer does not fall within said tolerance range (Δ

L) generation of an alert signal or analogue and/or digital interface signal indicating a possible malfunctioning of the detector.