Putting other cooling fan monitoring solutions in the shade

Modern cooling fan arrangements used in CCGT power stations are compact solutions for the removal of unwanted energy from the combined-cycle process.

They also play a critical role in the overall generation process, with fan failure resulting in potential lengthy downtime and an associated reduction in power plant generating capacity.


Wangnoi power plant cooling fan installation, Thailand
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Fans are typically arranged in groups of eight or more – facing vertically on raised platforms – driven through a motor and gearbox combination. Gearbox failure is common, caused by general wear and the imbalance produced through the fan rotation, which can be exacerbated by deterioration of the carbon fibre blades.

Trending of vibration levels on the gearbox enables plant engineers to plan inspection and maintenance of the fan assembly. Providing shutdown protection in the event of excessive vibration is also a key requirement for minimizing damage in the event of blade failure.

Sensonics’ DN2601 dual vibration monitor fulfills both these requirements and has been used for this purpose at EGAT’s Wangnoi power plant in Thailand. The site consists of three 600MW combined-cycle blocks, each with eight cooling fans. A single DN2601 is used to monitor each fan in combination with ICP type accelerometers, providing warning and shutdown alarm facilities in combination with 4-20 mA process signals fed to the plant-wide DCS for trending.

The Din rail-mountable unit provides a local display of vibration level, as well as a buffered transducer output to assist with more detailed fault analysis through a portable analyser.

Installed and commissioned by Sensonics’ Thailand partner Advance Siam Tech Company Limited in 2007, the system is now providing valuable fan condition monitoring data to assist the station in maintaining high levels of availability and efficiency.

How efficient are your filters?

British company Veotec Limited has developed a unique and cost effective way to measure the efficiency of air filters.

The Isokinetic Sampling System was developed to provide both filter manufacturers and end users with a way to measure the true performance of filters whilst in service without any interference to the plant. The product was originally designed for gas turbine intake systems, where the efficiency of the filter system is critical to the performance of the turbine and even small drops in efficiency can result in large reductions in the turbine performance.

Using this unique system it is possible to measure pressure drop and correlate efficiency with the En779 filter standard. These measurements are taken with the system operational without having to remove a filter and take it to a laboratory.

Who you gonna call?

The Seaward Group of the UK, a leading manufacturer of electrical test and measurement equipment, has extended its mobile calibration, commissioning and support service to cover all products and improve aftersales support and care for all customers.

Additional resources have been made available to support manufacturing and service customers of the Seaward, Clare Instruments, Cropico and Rigel brands in the UK.

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A team of fully trained engineers equipped with mobile support vehicles will provide on-site calibration for electrical safety testing instrumentation, digital microhmmeters and PAT testers among other similar equipment.

The fast and efficient calibration service means that instruments will continue to meet their required performance specifications with minimum disruption to working practices.

Seaward Group service manager Malcolm Steele said: “This is a further example of improving the support we offer customers through added value services and highly trained and skilled engineers.”

Water, water everywhere?

Water has led to the failure of everything from a missile to an integrated circuit, from a simple circuit board to an entire installation. Although seals and enclosures are excellent at keeping liquid water out, many of them offer virtually no barrier to water vapour – and it is often this that causes electronics to fail.

To solve this problem, permeability expert Versaperm Limited has launched a new way to measure this vapour permeability easily, quickly and accurately. It works on seals, enclosures, coatings, mastics and even finished products.

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The Versaperm MK VI water vapour transmission (WVTR) meter is quick, accurate and simple to use. It is highly automated and can cope with several samples at a time – and still give a reading in as little as 30 minutes for some materials. The conventionally gravimetric measurement technique takes several days and gives significantly less accurate and reproducible results.

The MK VI is accurate in the parts per million or parts per billion range depending on the gas used. The instrument can be configured to measure not just water vapour but most gases, including hydrogen, helium, hydrocarbons, oxygen, nitrogen and carbon.

As well as manufacturing the instruments, Versaperm offers a water vapour permeability laboratory service for companies that need to test samples on an irregular basis.

Polymeric product produces preferable pumps

Belzona Polymerics – providing solutions to industry for over 55 years through industrial protective coatings and repair composites – has a solution for pump lining, which has shown improved efficiencies in the pump post application.

Belzona has seen pump applications increase dramatically of late, as companies seek to minimize running costs by tackling issues of reduced efficiency.

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According to Belzona’s national sales manager, Gordon Cairns, the number of repairs undertaken by the group has nearly doubled in the last two years – more than any other type.

He commented: “Many companies are now working hard to reduce energy consumption, which forms the major part of a pump’s running costs.”

Independent testing from the UK’s National Engineering Laboratory in Glasgow has backed up Belzona’s claims of raised efficiency as a result of applying a smooth hydrophobic coating system.

Tests showed efficiency increases over new pumps of more than five per cent. This, supported by industry knowledge that efficiency losses due to erosion corrosion can be 12 or more percentage points, certainly substantiates the argument in favour of a Belzona coating solution.

Cairns said: “A major problem is increased turbulence, which is caused by erosion corrosion. This leads to roughening and pitting of wetted surfaces, which, in turn, increases drag, resulting in a significant loss in pumping efficiency.”

Belzona’s rigorous 55 years of research and development has resulted in proven solutions for pump repair and protection.

It uses rebuilding grade materials to first restore the original profiles and clearances without risk of distortion or heat damage followed by protective coatings to prevent the reccurrence of the original erosion/corrosion problems.

In recent years, specially developed hydrophobic coatings that provide a hydrodynamically smooth surface have been increasingly used to not only provide erosion/corrosion protection so as to maintain the pump’s efficiency, but to provide an actual increase in the pumps efficiency over its as-new condition.

Application of the coating will maintain, and normally increase, the original efficiency of the pump by providing a tough erosion/corrosion and hydrodynamically smooth surface.

Eastern promise for EA Technology

UK testing equipment manufacturer EA Technology has opened its own new sales offices in Shanghai, China and Abu Dhabi, UAE as part of a global growth strategy, which includes increasing the number of its international distribution partners from 16 to 25.

The Capenhurst, Cheshire-based power engineering specialist has also appointed a new head of international business development to further build the company’s presence worldwide. The new Shanghai office is headed by Dr Yuan Tian, a specialist in condition monitoring of HV equipment.

The new Abu Dhabi office is being managed by Alan Preece, a senior specialist in the condition of substations. Haydn Rees has been appointed to the new role of leader of EA Technology’s International Business.

EA Technology has also appointed five new distributors – in Portugal, Poland, Italy, Bahrain and Saudi Arabia.