| 摘要 |
There is a safety valve device in a connecting pipe (75), which has two main valve pistons (18, 26) and two control valve pistons (42, 53), actuation being by means of a control magnet (40, 51). In this arrangement, it is desirable for the connecting pipe (75) only to be opened with simultaneous actuation of the two control magnets (40, 51). This is achieved, in that the first main valve piston (18) releases access to the second control valve piston (53) in the locking position, which piston (53) in its turn, in the switched-on position, relieves the second main valve piston (26) for a changeover into the release position, and in that the second main valve piston (26), in the locking position, gives control oil access to the first control valve piston (42), which, in its turn, in the switched-on position, relieves the first main valve piston (18) for a changeover to the release position. The control oil for adjusting the two control valve pistons (42, 53) is thus alternately blocked off by the main valve pistons (18, 26) which have been made to adopt the release position. <IMAGE>
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