At Power-Gen Middle East Exhibition, Parker Instrumentation is showing a unique new family of check valves, specially optimised for the high temperatures and aggressive media found in turbine installations.

Now field proven in service in US dual-fuel power generation installations, the superior performance of the valves can eliminate costly turbine shut downs that can be required for repairs, maintenance, and fuel changeovers.

The CB Series of check valves provides a simple means of adding protection in any system where back flow or pressure might cause a problem or damage.

A typical power generation application is as unidirectional protection elements in the fuel oil, purge air or water lines to the combustion chambers of dual-fuel turbines.

Currently, such valves are often replaced or refurbished every few months to combat leakage as a result of coking, and/or the perishing of seals because of the aggressive media and the high temperatures (above 250F/121C).

This can be an extremely costly issue to deal with, especially for those installations that regularly switch between gas and oil - which tends to accelerate problems.

Superior performance and reliability is assured by special features including a floating ball with a micro-finished surface for accurate resealing, a Teflon coated ball cage, and seats fabricated from optimised materials that provide a soft sealing surface for excellent bubble-tight shut off combined with compatibility with fuel oils and amines.

These attributes guard against common problems associated with check valves in these environments, including formation of coke deposits, stuck poppets, chattering valves, and micro leakage that can accelerate deposit formation and catastrophic failure.

Fabricated in 316 stainless steel, Parker CB Series valves are available in 3/8, 1/2 and 3/4 inch sizes (9.5 to 19 mm).

Users can select springs for crack pressure ratings spanning a 1 to 120 PSI (0.07 to 8.3 Bar) range.

Users may also specify the valves for compatibility with existing systems or preferred installation practices by choosing from integrated single CPI or twin A-lok ferrule compression tube fittings, NPT, SAE, BSPP or JIC thread connections.

CB Series body shells will withstand pressures to 3,000PSI CWP (206 Bar).

Two types of seating material are commonly specified to suit this application's media and temperature requirements: Parkerfill or Parker Carbon (carbon graphite and carbon reinforced Teflon).

These seals are capable of operating at temperatures up to 500 or 550 F respectively (260 or 288 C).

Both materials are compatible with fuel oils and amines (ammonia derivatives), and resist coking.

Parker Carbon is generally used for higher pressure purge air applications and Parkerfill for water injection and fuel oil lines.

Both have been proven successful in dual fuel power generation applications, and are currently in service in numerous installations.

In addition to the standard components and sizes, Parker can supply check valves with application-specific features.

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