DuoPort® Pressure Relief Valve Manifolds for Small Storage Containers 8542 Series

Manifold Materials

Body Ductile Iron
Clapper Disc Stainless Steel
Bleeder Valve Stainless Steel
Seat Disc Teflon
Packing Polyethylene

Relief Valve Materials

Body Forged Aluminum*
Spring Guide Aluminum
Spring Coated Steel
Seat Disc Resilient Synthetic Rubber
*A special coating is applied to the inlet threads to minimize the possibility of electrolytic action

Designed especially for use as a primary relief device on smaller stationary storage containers, with 2” NPT threaded couplings. These manifolds allow servicing or replacement of either of the two relief valves without evacuating the container or loss of service. The operating lever selectively closes off the entrance port to the relief valve being removed while the remaining valve provides protection for the container and its contents. The rating of each manifold is based on actual flow through the manifold and a single pressure relief valve, taking friction loss into account. It is not merely the rating of the relief valve alone.


    • Allows for relief valve removal and replacement on a periodic basis without shutting down and evacuating the container.
    • Unique seat ring assemblies provide a smooth tubular section to preclude turbulence and assure more efficient flow capacity.
    • Operating lever is only locked in the mid-position or in a position to seal either relief valve. Placement of the clapper disc in an intermediate position could restrict flow through one of the relief valves, causing it to chatter and destroy the resilient seat disc.
    • A rubber plug with chain is provided to protect manifold outlet threads where the relief valve has been removed.
    • “Pop-action” design insures maximum protection with only minimal product loss at moderately excessive pressures.
    • Resilient relief valve seat disc provides “bubble-tight” seal.
    • Relief valves are ASME rated for use with LP-Gas and anhydrous ammonia.