Valve demonstrates reliability
March 1st 2006

In just over eight years seven Worcester Envirosafe ball valves and Norbro pneumatic actuators have completed 12 million cycles on a demanding application at a Middlesboroughbased fine chemicals manufacturer.

In that time there has been only one reported gland leak, which was taken up with a minor adjustment.

The valve/actuator combination controls an acidic liquor containing dissolved salts - including sulphates and chlorides - with a pH of 3.5 at temperatures to 50°C.

Due to the high cycling associated with the application, the valves can be operated as frequently as every 20sec.

In seeking a solution that would extend the intervals between valve changes, the company initially evaluated diaphragm valves before selecting Worcester Envirosafe E51 flanged ball valves. The stainless steel units have a dynamic, dual sealing stem arrangement and are controlled by Norbro pneumatic actuators.

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