Flow control device and flow control method

Abstract

The invention generally relates to a flow control device and a flow control methods. One embodiment provides a flow control device comprising: a first flow path to allow fluid to flow from an inlet port provided on an inlet side of the device to an outlet port provided on an outlet side of the device; a closure element arranged to prevent fluid flow along the first fluid path in a direction from the outlet port to the inlet port; and an arrangement adapted to open a second fluid path, different along at least part of its length from the first fluid path, in dependence upon the pressure of fluid at the outlet side, the second fluid path allowing fluid to flow from a first relief port provided on the outlet side to a second relief port provided on the inlet side, wherein the flow control device comprises an inner body part and an outer body part, the inner body part being sealingly arranged and moveable within the outer body part () between a first position and a second position under the influence of the pressure of fluid at the outlet side, wherein a first part of the second fluid path is formed within the inner body part and a second part of the second fluid path is formed within the outer body part, the first and second parts of the second fluid path being in communication with one another when the inner body part is in the second position but not when the inner body part is in the first position, thereby opening the second fluid path when the inner body part moves from the first position to the second position.