releasable a glance at the configuration of the lifting valve of fig1 shows that the closing member unit 4 if drawhooks 4 f are provided in the region concerned can be disassembled with no destruction involved if the valve rod 6 is initially removed from the valve rod bore 4 k of the closing member unit 4 and the adjoining drawhook 4 f is removed subsequently thereupon the drawhooks 4 f may be radially bent inwardly and may be removed from the bore 3 d in the box top 3 if the fastening component 4 f is configured in the form of a releasable bolted joint it will be no problem to disassemble it fig8 shows the closing member unit 4 which was already described previously and in its central portion comprises the bellows 4 b which at its end sides is connected to a box end connecting flange 40 each on one hand and the closing component 4 a on the other the bellows 4 b itself comprises a multiplicity of convex shaped and concave shaped bellows folds 40 b which alternately are lined up in this configuration with each convex bulged bellows fold 40 b as referred to the bellows interior defining a cavity h the closing member unit 4 is coaxially traversed by the valve rod 6 which runs to end in a threaded pin 6 a and along with it is screwed into the fastening socket.