Unique square core ups service life

A process valve has been developed which has a unique square core, resulting in much improved service life in fast, frequent operating environments. Dean Palmer reports

A new series of process valves for gases and fluids has been launched that offer a much improved service life of 20 million cycles, thanks to a unique design of square core. Asco Joucomatic's new 256 - 356 series of 1/8" process valves are designed for tasks such as shut-off, dosing, filling and actuator piloting in a wide range of applications including: sanitary equipment; industrial laundries; food machinery; compressors; heating and refrigeration; washing machines; milking machines; animal feeders; car washes; and welding machines. The two-way (2/2) and three-way (3/2) valves are direct-acting stainless steel or brass-bodied units designed for demanding applications that require fast (5 to 10ms) and frequent operation. The valves can be supplied as discrete units in NC, NO and universal configurations and also as manifolds, with two to five stations (valves) for stainless steel units and two to 10 stations for brass variants. The valves can be used with a number of fluids including air, water, hot water, detergents and chemical reagents, as well as gases such as oxygen, nitrogen and chlorofluorocarbon. The key to the valve's improved reliability and service life is its unique square core design, which provides a number of operational advantages. First, it prevents the build up of calcium when used with water. The core is square with slightly rounded corners and so when it rotates, there is minimal contact with the core tube, therefore reducing build up of calcium. With conventional designs, the core is typically round and so there is more contact with the core tube and so more chance of deposits building up. Second, the square core prevents the core malfunctioning when the valve is used with contaminated fluids. The square design offers less friction and so the valve is more efficient in operation. The reliability of the valves are further improved by a shock absorber located on the top face of the core, which not only prevents repeated hammering of the core surface, but also reduces noise levels significantly. Steve Meadows, marketing and customer services manager, told Eureka: "As far as I'm aware, most competing process valves offer a service life of around one million cycles, so a unit that offers 20 million cycles is very impressive." The valves are compact, lightweight and offer users a wide range of flow and pressure ratings. They can operate with high differential pressures of up to 35 bar. And the fitting of FPM (Viton) seals, as standard, enables the units to operate at temperatures up to 100°C. The facility for 24V DC operation and the integrity of the design means the valves are suitable for outdoor use without any specific protection. Captive O-rings ensure excellent sealing between the coil and the core tube and also prevent moisture from entering the coil actuation mechanism. The coil itself is rated to IP65. The 256/356 series valves come with an extensive 'options' list, including EPDM; NBR or PTFE seals; spade plug connectors to IP67; explosion-proof enclosures for use in zones 1/21, 2/22 categories 2-3 to ATEX Directive; flying leads; magnetic latch execution; plugs with visual indication; oxygen service valves; and valves without manual operators.