Storm Valves

Marine shell check valves are used on drainage and overboard discharge lines where one-way flow is required and backflow of seawater into the vessel’s internal piping must be prevented. Their operation is based on a non-return flap mechanism that opens under normal discharge flow and closes under backpressure, wave action, or external hydrostatic head.

This category includes steel storm valves to JIS standards, with flanged connections in 5K and 10K pressure classes. Available configurations cover straight-through flow type F3059 and angle flow type F3060, allowing selection according to piping geometry, outlet position, and available installation space.

Straight-through F3059 versions are typically used where the pipe run discharges directly to the shell outlet with minimal change of direction. Angle pattern F3060 versions are used where the installation requires a change in flow direction at the valve location, or where flange orientation and limited space near the shell plating or in machinery spaces require a more compact arrangement. JIS 5K and 10K classes must be matched to the flange standard of the connected piping and should not be treated as interchangeable without dimensional verification.

Valve selection should consider installation height relative to the waterline, expected backpressure, flow direction, seawater corrosion exposure, access for inspection of the flap and seat, and compliance with vessel class requirements. During periodic maintenance, checks should include free movement of the flap, cleanliness and condition of the seating surface, gasket condition, wear from entrained solids, and shut-off tightness against reverse flow.