Gas nozzles for gas using appliances

A gas-using appliance comprising a gas container having an exterior tubular socket, the bottom of which is connected by a passage to the interior of the gas container and the top of which is open and a gas nozzle device, said gas nozzle device comprising an elongated piston member slidable in the tubular socket having one end projecting from the top of the socket and presenting a surface of contact, a cap member mounted on the projecting end of the piston member and presenting a surface of contact abutting against the surface of contact presented by the piston member, said cap and piston members being relatively rotatable and each having a passage one end of which is located in the surface of contact of the respective member and the other end of which is located at the other end of the respective member, the ends of the two passages on the respective surface of contact being eccentric with respect to the axis of relative rotation of the members by amounts such that the locus of at least one point on the periphery of the end of the passage in one member in different relative angular positions of the two members is an orbit, a portion of said orbit being within the periphery of the end of the passage in the other member, seal means located at the bottom of the socket, means for rotating the cap member and the piston member relatively to one another and means for reciprocating the piston member in the socket into and out of contact with the sealing means whereby to close and open said other end of the passage in the piston member.