Parker's CK4 check valves are designed to be close coupled to a control valve which will reduce overall installation length, complexity, and cost. These valves are designed to prevent backflow in a variety of refrigeration applications and can be mounted on a valve or as a standalone component. The CK4 can be mounted in any orientation when used as a standalone part of the refrigeration system. These compact valves are spring closing with a lapped, stainless steel or chrome plated seat for positive closing action and low leakage. A minimum pressure difference of 0.05 bar (0.75 psi) is required to hold the valve in the open position. Removable seat plate with combination O-ring and metal to metal knife edge seal allows the valve to be disassembled for maintenance. They may be ordered with male adapter rings for close-coupling to other Refrigerating Specialties valves.