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Report presents measurement of acoustic spectra from liquid leaks
sealing
TECHNOLOG TECH NOLOGY Y
ISSN 1350-4789 February 2008
www.sealingtechnology.info
Report presents measurement of acoustic spectra from liquid leaks
T
he Health and Safety Laboratory in the UK has completed a project to investigate the response of acoustic leak detectors to liquid releases and to produce guidance for their acceptable use on offshore platforms. Acoustic leak detection (ALD) is being used increasingly in the offshore industry as an additional and complementary means of detecting leaks of flammable substances on offshore platforms. There is an increasing desire across the offshore industry to adopt these devices for detection of liquid releases as well as gaseous releases. ALD instruments have been proven to be effective so far only for gaseous releases. However acoustic leak detectors have in some circumstances been shown to be able to respond to the noise generated by liquid releases under pressure. Industry and HSE are however, not in a position to accept the use of these devices for detecting liquid releases because their response to such leaks has not been fully characterised. The work reported has set out to provide further information on the performance of detectors with a liquid release. Three types of acoustic leak detectors from two manufacturers were used for the programme of work which involved: • Initial releases of air at pressures up to 100bar in order to characterise the release facility and
• • • •
provide a base-line sensitivity for the sensors. Releases of water at pressures up to 100bar. Hydrocarbon releases including liquid propane, diesel and diesel/propane mixtures. Releases using a variety of release scenarios intended to simulate realistic leakage conditions. Recording of acoustic spectra from the releases.
All of the releases gave rise to broadband, random noise into the ultrasonic range. ALD were most effective detecting air leaks. The sound pressure level of the releases increases with increasing release pressure, although the rate of increase against the release pressure is variable. If ultrasonic leak detectors are to be used to detect liquid or mixed phase leaks they will require a higher sensitivity due to the lower ultrasound levels. A critical factor in effective ALD is the monitoring of the background noise A comprehensive report on the testing, RR568 – Measurement of acoustic spectra from liquid leaks, has been published by HSE Books and is available from the address below or for free download from the HSE website. Contact: Offshore Division, HSE, Redgrave Court, Merton Road, Bootle, Merseyside, L20 7HS, UK, Tel: +44 151 951 3144, Fax: +44 151 951 3131, Email: [email protected], Web: www.hse.gov.uk/research/rrpdf/rr568.pdf.
The test manifold for the testing of acoustic leak detectors had five valves set up to simulate a number of common process leakage scenarios.
Contents News
1–6, 16
In Brief
3
Company News
4
Conference & Courses Update
5
FSA News
6
Feature: Improving mechanical seal reliability with advanced computational engineering tools, part 2: CFD and application examples Patents
7–10 11–15
Events Calendar
16
Food, beverage and pharmaceutical information added to website
T
relleborg Sealing Solutions has added industry specific information to the company website focusing on food, beverage and pharmaceutical processing. This provides an overview of the product and material portfolio specially developed for this market. It also provides information on the driving forces in this market including details on material approvals, CIP and SIP, hygienic design products, seal life testing and other sector specific information. The industry specific content is divided into five sections; materials, products, approvals, CIP & SIP and applications. Contact: Trelleborg Sealing Solutions, Global Marketing & Communications, Handwerkstrasse 5–7, D-70565 Stuttgart, Germany, Tel: +49 711 7864 0, Fax: +49 711 7864344, Email: Donna.Guinivan@trelleborg. com, Web: www.tss.trelleborg.com.
ISSN 1350-4789/08 © 2008 Elsevier Ltd. All rights reserved. This journal and the individual contributions contained in it are protected under copyright by Elsevier Ltd, and the following terms and conditions apply to their use: Photocopying Single photocopies of single articles may be made for personal use as allowed by national copyright laws. Permission of the publisher and payment of a fee is required for all other photocopying, including multiple or systematic copying, copying for advertising or promotional purposes, resale, and all forms of document delivery. Special rates are available for educational institutions that wish to make photocopies for non-profit educational classroom use.
TECHNOLOG TECH NOLOGY Y
ISSN 1350-4789 February 2008
www.sealingtechnology.info
Report presents measurement of acoustic spectra from liquid leaks
T
he Health and Safety Laboratory in the UK has completed a project to investigate the response of acoustic leak detectors to liquid releases and to produce guidance for their acceptable use on offshore platforms. Acoustic leak detection (ALD) is being used increasingly in the offshore industry as an additional and complementary means of detecting leaks of flammable substances on offshore platforms. There is an increasing desire across the offshore industry to adopt these devices for detection of liquid releases as well as gaseous releases. ALD instruments have been proven to be effective so far only for gaseous releases. However acoustic leak detectors have in some circumstances been shown to be able to respond to the noise generated by liquid releases under pressure. Industry and HSE are however, not in a position to accept the use of these devices for detecting liquid releases because their response to such leaks has not been fully characterised. The work reported has set out to provide further information on the performance of detectors with a liquid release. Three types of acoustic leak detectors from two manufacturers were used for the programme of work which involved: • Initial releases of air at pressures up to 100bar in order to characterise the release facility and
• • • •
provide a base-line sensitivity for the sensors. Releases of water at pressures up to 100bar. Hydrocarbon releases including liquid propane, diesel and diesel/propane mixtures. Releases using a variety of release scenarios intended to simulate realistic leakage conditions. Recording of acoustic spectra from the releases.
All of the releases gave rise to broadband, random noise into the ultrasonic range. ALD were most effective detecting air leaks. The sound pressure level of the releases increases with increasing release pressure, although the rate of increase against the release pressure is variable. If ultrasonic leak detectors are to be used to detect liquid or mixed phase leaks they will require a higher sensitivity due to the lower ultrasound levels. A critical factor in effective ALD is the monitoring of the background noise A comprehensive report on the testing, RR568 – Measurement of acoustic spectra from liquid leaks, has been published by HSE Books and is available from the address below or for free download from the HSE website. Contact: Offshore Division, HSE, Redgrave Court, Merton Road, Bootle, Merseyside, L20 7HS, UK, Tel: +44 151 951 3144, Fax: +44 151 951 3131, Email: [email protected], Web: www.hse.gov.uk/research/rrpdf/rr568.pdf.
The test manifold for the testing of acoustic leak detectors had five valves set up to simulate a number of common process leakage scenarios.
Contents News
1–6, 16
In Brief
3
Company News
4
Conference & Courses Update
5
FSA News
6
Feature: Improving mechanical seal reliability with advanced computational engineering tools, part 2: CFD and application examples Patents
7–10 11–15
Events Calendar
16
Food, beverage and pharmaceutical information added to website
T
relleborg Sealing Solutions has added industry specific information to the company website focusing on food, beverage and pharmaceutical processing. This provides an overview of the product and material portfolio specially developed for this market. It also provides information on the driving forces in this market including details on material approvals, CIP and SIP, hygienic design products, seal life testing and other sector specific information. The industry specific content is divided into five sections; materials, products, approvals, CIP & SIP and applications. Contact: Trelleborg Sealing Solutions, Global Marketing & Communications, Handwerkstrasse 5–7, D-70565 Stuttgart, Germany, Tel: +49 711 7864 0, Fax: +49 711 7864344, Email: Donna.Guinivan@trelleborg. com, Web: www.tss.trelleborg.com.
ISSN 1350-4789/08 © 2008 Elsevier Ltd. All rights reserved. This journal and the individual contributions contained in it are protected under copyright by Elsevier Ltd, and the following terms and conditions apply to their use: Photocopying Single photocopies of single articles may be made for personal use as allowed by national copyright laws. Permission of the publisher and payment of a fee is required for all other photocopying, including multiple or systematic copying, copying for advertising or promotional purposes, resale, and all forms of document delivery. Special rates are available for educational institutions that wish to make photocopies for non-profit educational classroom use.