U.S. Plastic Corp.® carries an extensive selection of Y-Valves. Y-Valves prevent reversal of flow in piping systems.  They are ideal where backflow could potentially cause damage to pumps, filters or process equipment.  The Y-Valves operate without the need for any adjustments or settings. A plastic coil or spring, depending on the valve, supports the disc inside the valve body.  When the inlet flow stops, backpressure moves the disc/spring shutting off the flow.