Stop Check Valves
Screw-down check globe valves for marine service combine manual isolation with automatic backflow prevention. They are used in shipboard piping systems where shut-off capability is required together with restriction of reverse flow toward pumps, heat exchangers, tanks, or auxiliary equipment. Operation is based on a check disc/plug, while the handwheel mechanism allows positive mechanical closure for maintenance, line isolation, or equipment protection.
This category includes straight-pattern and angle-pattern JIS designs with flanged ends in 5K, 10K, and 16K pressure classes. Available series include bronze valves F7351, F7352, F7409, and F7410; cast iron valves F7375, F7376, F7377, and F7378; and cast steel valves F7471 and F7472.
Bronze-bodied valves are generally applied in auxiliary water systems and smaller-bore marine services, subject to compatibility with the process medium and installation environment. Cast iron 10K and 16K types are used in general engine-room services. Cast steel constructions are selected where higher mechanical strength is required or where operating pressure and temperature impose stricter material and pressure-retaining requirements.
For reference, type F7375 is specified to JIS F7375-1996, with testing in accordance with JIS F7400-1996 and a hydraulic shell test pressure of 2.1 MPa. Type F7471 is specified to JIS F7471-1996, also tested to JIS F7400-1996, with hydraulic shell testing at 2.1 MPa.
Valve selection should consider JIS pressure class, flow direction, straight or angle installation geometry, body material, handwheel accessibility, pressure drop, and periodic inspection requirements for seat, disc, stem, and packing. Media type, allowable leakage, maintenance interval, and service temperature should also be checked before specifying the valve for continuous marine operation.