Abstract: A double check valve (10) with two separate elements (20, 25) individually movable to close the valve and collectively movable to open the valve. The separate elements are independently closing the valve, and collectively controllable to open the valve, to allow pressure release or to allow injection of fluid (e.g. lubricant). In an example, the double check valve includes two separate check valves with a stinger element (30) between them which is operable to internally sting the one check valve when (e.g. by action of) the other check valve is stung by a user (e.g. using a stinger means) thereby to open both check valves individually and the double check valve as a whole.

Abstract: A double check valve (10) with two separate elements (20, 25) individually movable to close the valve and collectively movable to open the valve. The separate elements are independently closing the valve, and collectively controllable to open the valve, to allow pressure release or to allow injection of fluid (e.g. lubricant). In an example, the double check valve includes two separate check valves with a stinger element (30) between them which is operable to internally sting the one check valve when (e.g. by action of) the other check valve is stung by a user (e.g. using a stinger means) thereby to open both check valves individually and the double check valve as a whole.

Abstract: A pipeline coupling comprises first and second substantially annular connecting pieces at each end of a length of pipe, an internally threaded nut on the first connecting piece and a corresponding external thread on the second connecting piece, and a sealing ring for location between adjacent ends of two lengths of pipe to be connected, a sealed connection between the two lengths of pipe being effected by screwing the nut onto the external thread to draw the connecting pieces axially towards one another and to compress the sealing ring therebetween. A substantially annular locking ring is mounted on the second connecting piece to be axially movable therealong but rotatably fixed relative thereto, the locking ring and nut being provided with corresponding projections and recesses adapted to engage with one another to prevent relative rotation between the two connecting pieces, releasable means retaining the projections and the recesses in engagement with one another.

Abstract: A swivel joint for pipes includes a split collet carried by a male portion of the coupling, and which provides an abutment for a threaded annular nut carried by a female member of the coupling, the nut being lockable in its adjusted position, the male member being rotatable within the female member to provide for swivelling of the joint.