The RGR CONCENTRIC CHECK VALVE SERIES C1 is a tree piece, axial flow, spring assisted check valve. The valve is designed to open at low flow rates and due to the venture shaped internal spider housing, the pressure drop across the valve is kept to a minimum. The disc is mounted in a bearing housing. The housing is supported by a spider assembly which forms part of the internal venture. Flow through the venture causes a pressure drop which assists in opening the valve. Sealing is provided by a primary soft seal and a secondary metal to metal seal. The soft seal is held onto the disc by a retaining ring and cannot be removed by media flowing through the valve. The disc seals against a replaceable body seat. A coil spring assists with the closing of the valve and also ensures ultra fast closing without backflow thus preventing pressure surges.