Selecting the Correct Valve for the job

1/21/20, by Toni Wall

Customer Case Study

Recently while visiting a pulp and paper customer our Territory Sales Manager, Tom was posed with a problem to solve. Our customer was experiencing inconsistencies in their pulp stock.  The reason seemed to stem from an old control valve that was installed in their white water dilution system.  The valve was a standard flanged stainless steel ball valve with a rack and pinion pneumatic actuator. Although ball valves are a cost-effective way to provide leak-proof service when you require finer control this style valve is not the best option.

Tom’s suggestion, with the help from our friends at Neles, was a RE Series, V-ported segmented ball valve with a Quadra-Powr®-X (QPX) actuator. Unlike a traditional ball valve that is primarily designed for on/off applications, the v-port utilizes a segmented, half-ball design, which allows for precise control and variable flow rates. That control comes in through its v-ported design. This quarter-turn style valve allows for the economic advantages of a ball valve but with better flow control more aligned with a globe valve, without the added expense. In summary, v-segmented ball valves allow for greater Cv (flow control) than an equally sized globe valve. It requires lower torque to throttle the segment, minimizing friction while at the same time providing exceptional control allowing it to fit a broader range of applications.

The change in actuator was a good call as well. The QPX spring diaphragm operators provide safe, reliable operation even with minimal supply pressures are available. A rack and pinion style will have some “slop/movement” in the teeth/gearing of the piston that does not allow for precise control, hence why it is normally used for on/off or rough control applications. In the QPX the diaphragm eliminates those parts to allow for more precise control.

The take away, technology has advanced our industry over the last ten years. Before replacing your leaky valve with the same style replacement, contact us and let us do a thorough analysis of the application and suggest the best option for the efficiency of your plant.