Materials Switch Boosts Valve's Reliability, Reduces Production Costs

Peter Paul Electronics, New Britain, CT, has found improved product performance and reduced manufacturing costs for its Series 40 solenoid-operated valve with help from DuPont Engineering Polymers, Wilmington, DE. The redesigned valve is engineered for competitive cost and reliable service in humidifiers, pneumatic actuation systems, beverage dispensers and other equipment.
Rynite's strength and moldability allows integration of support bracket into encapsulation.

The new valve's solenoid assembly is encapsulated with thermoset epoxy and the valve body was metal. Existing valve lines use thermoset epoxy encapsulation and the bodies are made of machined brass, stainless steel or aluminum.

"In switching to Rynite for encapsulation, we got much shorter cycles, eliminated VOC (volatile organic compound) emissions from the epoxy and eliminated secondary finishing," says Tom Pellegatto, senior design engineer for Peter Paul. The strength and moldability of Rynite also allowed the integration of a support bracket into the encapsulation.

Another key feature of the new design is the use of the inner diameter of the bobbin to guide the valve's plunger. This eliminates a precision-welded metal assembly incorporating a nut, a guide sleeve for the plunger and end stop. A cylindrical metal end stop, which limits plunger travel, is now insert-molded in the encapsulation. Tolerances for end stop positioning are much closer with the new design, ±0.0002 in. instead of ±0.005 in., which helps assure consistent valve operation.

The valves have operated without failure for 20 million cycles with water and air at temperatures from 32 to 120°F. They are available with orifices from 1/32- to 1/8-in., and are rated for service pressures up to 250 psi. For pneumatic control applications, a 3-way version is made with a port at the top to exhaust air from downstream cylinders when the valve closes.

--KC

For more information:

Circle 519 - Peter Paul Electronics Co. or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/005df-519

Circle 520 - DuPont Engineering Polymers or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/005df-520