Increased seat life is obtained by eliminating the problem of the plates dragging on the seat when opening. Due to the clearance between the plate hinge and the hinge pin the heel of the plate lifts with the initial flow, as the foot of the spring acts beyond the centre of pressure of the plate. As the flow then increases through the valve the plates open without the heels of the plate scuffing the body seat.

The independent spring action optimizes the equal closing rates of each plate especially when friction coefficients are uneven due to one plate resting upon another. The springs have been designed to ensure stresses are kept to a level so that the spring should have a theoretical infinite life. Spring designs utilized in our  valves have undergone accelerated laboratory testing and are proven to be capable of operating without failure over 2,000,000 cycles.

The dual plate check valve is tested to API 598 which has a metal to metal seat permitted seal leakage of 3 cc/inch of bore/min. This small but significant amount arises because it is more difficult to obtain a perfect seal on a D shaped seat compared to a circular seat. Our plates (Pat) have been specifically designed to overcome this problem and to be better at sealing than earlier designs, such that near zero leakage can be economically achieved on metal to metal seats. This is particularly useful on high temperature gas applications and cryogenic applications where it is not possible to use resilient seats. In contrast to other dual plate check valves the seat sealing characteristics of the valve does not significantly deteriorate as line pressure increases. This characteristic enables us to provide dual plate check valves with substantially lower leakage rates than specified in API 598 at no additional costs.

The engineer no longer needs to worry about whether spiral wound gaskets or ring joints are compatible as  our design design accommodates both USA and European sealing elements.

Not only does the retainerless design provide a higher integrity pressure vessel - no screwed plugs, it also enables the valve to be disassembled very quickly without the use of force or special tools other than an Allen wrench. The  Wafer and Flanged design concept is such that it is impossible for the valve to become disassembled in the line and does not utilize any springs or circlips.
With improved machining technology We are able to offer this superior design as standard at a price equal or less than competitors’ valves with retaining plugs.