Abstract: A liquid container with an outlet pipe has a closure for the outlet pipe comprising a cap screw and a closure element disposed between the outlet pipe and the cap screw. The closure element has an integral sealing diaphragm across its bore, which diaphragm may be ruptured to initiate flow of the liquid. The sealing diaphragm has a cup-shaped depression at its periphery. The cap screw has a coarse thread on one side that mates with screw threads on the outlet pipe, and a finer thread on the other side for receiving a flow control member. The cap screw has an internal flange between the two sets of screw threads, which contacts an external flange on the closure element. The cap screw carries an external screw engageable with the container to prevent undesired rotation of the cap screw.