Abstract: A valve assembly, comprising a first fluid port, a second fluid port, a valve seat comprising an inner valve seat and an outer valve seat, and a moveable plunger, being moveable between a closed position and an open position arranged to simultaneously seal the inner valve seat and the outer valve seat when in the closed position. A first fluid pathway passes via the inner valve seat, and a second fluid pathway passes via the outer valve seat between the first and second fluid ports when the movable plunger is in the open position. At least one fluid flow path is provided through the body of the moveable plunger. The cross-sectional area of the flow path through the moveable plunger is at least half of the cylindrical cross-sectional area of the gap between the plunger and the respective inner or outer valve seat.

Abstract: A valve assembly having an inner and outer concentric valve seat. The inner valve seat is arranged radially inward of the outer valve seat to provide an annular opening therebetween. A movable plunger moves between a closed position and an open position to vary a flow restriction at the inner and outer valve seats and simultaneously seal the inner and outer valve seats in the closed position. An inner and outer valve member comprise the inner and outer valve seats and are separate components mounted in fixed relation to one another. The inner and outer valves seats are radially aligned to maintain concentricity of the inner valve seat relative to the outer valve seat and axially aligned to maintain axial alignment of the inner valve seat relative to the outer valve along an axis, wherein the axis is substantially orthogonal to a plane of the inner and outer valve seats.

Abstract: There is provided a valve assembly (100). The valve assembly comprises a valve seat comprising an inner concentric valve seat (104) and an outer concentric valve seat (105), the inner concentric valve seat being arranged radially inward of the outer concentric valve seat to provide an annular opening therebetween. The valve assembly also comprises a movable plunger (107), being movable between a closed position and an open position to vary a flow restriction at the inner and outer concentric valve seats, and arranged to simultaneously seal the inner concentric valve seat and the outer concentric valve seat when in the closed position. The valve assembly also comprises an inner valve member (124) comprising the inner concentric valve seat and an outer valve member (125) comprising the outer concentric valve seat. The inner valve member is a separate component from the outer valve member and is mounted in fixed relation to the outer valve member via mounting means.

Abstract: There is provided a valve assembly, comprising, a first fluid port, a second fluid port, a valve seat comprising an inner valve seat and an outer valve seat, the inner valve seat being arranged within the outer valve seat, and a moveable plunger, having a body and being moveable between a closed position and an open position to vary a flow restriction at the valve seat, and arranged to simultaneously seal the inner valve seat and the outer valve seat when in the closed position. A first fluid pathway is provided between the first fluid port and the second fluid port passing via the inner valve seat when the movable plunger is in the open position, and a second fluid pathway is provided between the first fluid port and the second fluid port passing via the outer valve seat when the movable plunger is in the open position. At least one fluid flow path is provided through the body of the moveable plunger comprising an opening configured to form part of the first fluid pathway or the second fluid pathway.