Double Ball Check Valves
CPI Double Ball Check Valves are designed for high pressure applications where reverse flow / leakage must be kept to minimum. Typical applications include engine, pump and compressor cylinder / packing lubrication and hydraulic systems. A relatively stiff spring in these check valves serves to increase the reliable of the circuit.
Flow entering the check valve creates pressure on the smaller ball (5). If the pressure created is higher than the opposing force of the spring (3), the smaller ball is moved off its seat. This allows flow to create a similar pressure and action on the large ball (6) and spring (4). Flow continues on to the outlet of the check valve. If flow is reversed, flow force and spring (4) cause the large ball (6) to be reseated. Any leakage around the large ball (6) is blocked by the smaller ball (5) that is firmly seated by spring (3).