Back Pressure Valves are designed to dependably maintain a desired pressure in a vessel or system by maintaining a predetermined valve inlet pressure and relieving excess pressure into a lower pressure line. Back pressure valves are not emergency relief devices, but are designed for continuous pressure regulation.  Cash Valve has an extensive line of back pressure and bypass valves.  Full specifications of construction, dimensions and available pressure ranges are contained in separate data sheets.  Please visit www.cashvalve.com.