Converting a precision-machined brass casting into a molded assembly complete with threaded inserts proved challenging for Minnesota Rubber and Plastics’ design engineers.
Before (left) – Water control valve for water softeners is cast from heavy brass and required multiple precision machining operations. After (right) – New molded assembly provides a lighter weight, total sealing solution from Minnesota Rubber and Plastics.
The project – a dual tank water treatment control valve that provides a continuous supply of softened water from one tank while a second tank is being regenerated. Critical to reliable water softener function, the control valve regulates flow rates for resin regeneration, rinsing and flushing of the water in the softener. Measuring 5 x 3-3/4 x 5 inches, the valve services both resin tanks of the water softener system through a series of complex internal flow paths. The current brass valve requires costly secondary machining to create all the flow paths, which are now molded complete. The valve also required 15 threaded brass inserts on four sides where incoming and outgoing connections are made.
The design challenge for Minnesota Rubber and Plastics was to provide a molded water control valve equal to or better than the existing brass water control valve without sacrificing water flow rates while meeting regulatory requirements for structural performance and water purity. Price targets along with just-in-time delivery were also key requirements of the project.
Three piece-molded assembly is hot plate welded together for a watertight seal of the valve body. Going to a molded valve design eliminated many machining operations.
For this project, a three-part valve body configuration was arrived at with the three components hot plate welded together.
Advantages of the new water control valve include: a 75 percent weight reduction, non-corrosive reinforced thermoplastic body, identical inlet and outlet plumbing connections as on the brass valve, along with leak and pressure testing of each welded valve prior to shipping.
Minnesota Rubber and Plastics
www.mnrubber.com
Filed Under: Fluid power, Hydraulic equipment + components, Valves
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