In a little over 8 years seven Worcester Envirosafe ball valves and Norbro pneumatic actuators have completed no less than 12 million cycles on a demanding application at a Middlesbrough-based fine chemicals manufacturer. According to the company, since the valves were installed in 1997 there has been only one reported gland leak – which was taken up with a minor adjustment. The valve/actuator combination is used to control an acidic liquor containing dissolved salts – including sulphates and chlorides – with a pH of 3.5 at temperatures of up to 50C. Due to the high cycling associated with the application the valves can be operated as frequently as every 20 seconds. The Worcester Envirosafe E51 stainless steel flanged ball valves feature a dual sealing stem arrangement and are controlled by Norbro pneumatic actuators.
