Quick view Eddington Eddington 1/2" NPT Back Pressure Valve with Viton Diaphragm MSRP: $0.00 - $236.00 Back pressure valves using diaphragms are designed to protect pumping systems from over pressure damage caused by defective equipment or blockage in the pump system line. Eddington Industries is a... MSRP: $0.00 - $236.00 Quick Add Add to Wish list Compare