Abstract: A fluid flow check valve with two disc closure elements pivotally mounted in the valve's body. A concave surface on the upstream side of each disc assists in stabilizing the discs against flutter during flow through the valve, and angular lugs on the downstream side of the discs cooperate with a stop shaft to further stabilize the assembly when the discs are fully open. The valve also includes a resilient seat with an annular sealing bead to facilitate a high unit load on the seat at low pressures, and with a large seal area to support the discs at high back pressures.