Don't Settle for a DRAG® Copy Cat!

Layyah Power Station has been experiencing problems of seat and plug erosion in their boiler feed pump recirculation valves since these valves were installed several years ago. Cause of the plug and seat erosion was traced to cavitation damage in the valve trim. This damage forced Layyah power plant to replace the valve seat every year and replace the plug every other year. This frequent maintenance not only increased plant maintenance costs but also reduced the plant’s operating time. In addition, plug and seat damage resulted in heavy leakage of precious hot water which, in turn, resulted in significant plant efficiency loss.

Layyah found out that cavitation in the trim was caused by a poorly designed disk stack, an imitation of the CCI DRAG®&Mac226; design. To solve this problem, CCI proposed a replacement 2- x 2-in (50-mm) angle valve that will feature a CCI designed DRAG®, multi-path, multi-stage disk stack. This technologically advanced and proven design will incorporate the exact number of turns scientifically calculated to keep trim exit velocities below 75 f/sec (23 m/sec) (ISA criteria for trim exit velocity in cavitating service).

It is due to CCI’s unique pressure-reducing DRAG® design that trim exit velocities are controlled, eliminating possibility of cavitation related problems such as plug and seat erosion. In addition, proposed CCI valves for Layyah power plant will use Inconel trim materials to minimize wear and enhance life of the trim components. Furthermore, high thrust CCI actuators will ensure tight shut-off and minimize any possibility of leakage. Since imitation designs do not have the benefit of CCI’s four decades of experience of DRAG® technology, they do not incorporate the advanced features of tried and true CCI technology. These features are essential for reliable valve performance in severe service applications as well as maximizing plant efficiency.

Published in SOLUTIONS Fall 2001