Product category:
Condition monitoring and vibration analysis
News Release from: AV Technology | Subject: Remote visual inspection
Edited by the Processingtalk Editorial
Team on 09 March 2007
Power generation needs remote visual
inspection
Remote visual inspection - video images - are playing an increasingly important role in preventative maintenance and troubleshooting at power generation plants
Remote visual inspection is playing an increasingly important role in preventative maintenance and troubleshooting at power generation plants The technique uses remotely controlled video cameras, video probes or fibre-optic probes to obtain detailed visual information from inaccessible locations
This article was originally published on Processingtalk on 4 Apr 2007 at 8.00am (UK)
Related stories
The new role of remote visual inspection
Remote visual inspection is playing an increasingly important role in preventative maintenance and troubleshooting: Ken Lambert of AVT gives some recent examples
Accelerometers keep an eye on drilling platform
Specialist structural monitoring consultants, AV Technology, are playing a vital part in ensuring the safety of the Chirag-1 oil production platform, situated in the Gunashli field in the Caspian Sea
In many cases, the inspection forms part of a wider investigative programme, which may also involve debris retrieval, corrosion assessment or routine repairs.
Where applicable, video images can be used to support data from other techniques such as crack detection.
Stockport based AV Technology (AVT) have the experience, expertise and ingenuity to provide comprehensive internal visual inspection services, and advice, at all types of plants, including oil, gas, coal, CHP, nuclear and hydro-electric.
Further reading
When machines talk, it pays to listen to vibration
AV Technology Ltd has been awarded an important predictive maintenance contract by Anglesey Aluminium Metal/Aliwminiwm Mon and the structured programme is already paying dividends
Unique approach to silo weighing is retro-fitted
The Silo-Weigh system has successfully completed a six month trial on a huge 30 metre high, 500 tonne soda ash silo at Pilkingtons Greengate flat glass manufacturing site at St Helens, Lancashire
Testing to prevent hand-arm vibration syndrome
New regulations require strict maximum levels of exposure to vibration equipment in the workplace, to help prevent Hand-Arm Vibration Syndrome: AV Technology can provide solutions for employers
The AVT work includes inspections on.
* Boiler headers.
* Turbines.
* Attemperator nozzles.
* Pipe-work and pipe linings.
* Valves.
The trend towards increased outage periods means that inspections, when they are carried out, must be very thorough.
Although it is possible for companies to perform inspection work themselves, AVT, who have over 25 years experience in remote inspection, firmly believe there are significant reasons why it makes sense to employ the services of a professional and experienced inspection company.
As AVT vision inspection expert Ken Lambert points out: "Although it may seem straightforward to hire the cameras and equipment, actually carrying out the work *effectively*, and safely, is far from simple.
Without the experience, and expertise in the use of purpose built accessories for positioning cameras, companies who carry out their own inspections usually end up with low quality images which often do not provide sufficient useful information.
In addition, interpreting and presenting the results so that further work, based on this data, can be carried out, requires considerable expertise.
Work in pipes typically involves routine inspections of welds, valve seat conditions, blockages and build-up of process product.
Visual inspections can also be effective in assessing the effects of flow accelerated corrosion (FAC).
Filming inside pipes and similar small enclosed spaces requires a mixture of the right equipment, ingenuity and skill.
Entrance apertures may be relatively small and radial inspections require specially converted camera assemblies.
For small diameter, short length inspections of up to six metres, fibre optic endoscopes or video probes are used.
For larger and longer inspections, a video camera mounted in a multi-legged centralising cradle allows pipe lengths up to 300 metres to be inspected.
The cradles are usually propelled either by flexible rods or a remote controlled, motorised carriage.
These remote crawlers give greater flexibility and are used in longer distance, more complex situations.
In these applications, great operator skill is required to ensure that the crawlers do not become stuck.
During the past decade there have been an increasing number of unexpected incidences of failures or crack indications in utility boiler pressure components.
This is primarily due to the aging of the steam generating equipment base.
Also, the condition of the components can be severely impacted by the continued trend towards cycling and load-swinging modes of boiler operation.
Of particular concern are the on-going occurrences of header and drum internal cracking.
Attemperators located in the superheater crossover piping are used to control the steam temperatures by introducing spray water to the steam flow.
Cracking is typically due to thermal fatigue, a result of over temperature conditions and cyclic or load swing operation.
An important associated part of remote inspection is debris retrieval: 'Debris' can include parts that have broken off or material left after construction or repair work.
It is not uncommon to find objects such as tools, nuts and bolts!.
Waterproof cameras are available for underwater inspection and a wide range of accessories including lateral view heads, headlamps, and air-cooling jackets for high temperature applications, increase the possibilities for remote inspection.
As with all professional photography, the pre-requisite for clear and usable images is ensuring correct lighting and focus.
Ken Lambert concludes: "It is clear that remote inspection provides a very powerful tool.
Our experience in the power industry has shown that combining this technology with practical ideas and sound mechanical engineering methodology significantly extends its capabilities.
We advise clients to discuss their application with us before they try to carry out any work themselves.
We offer a highly professional service with all the relevant health and safety, QA and insurance certification". Request a free brochure from AV Technology ...
• AV Technology: contact details and other news
• Email this article to a colleague
• Register for the free Processingtalk email newsletter
• Processingtalk Home Page
