| 摘要 |
A plate type filter press, which is opened and closed by at least one hydraulic piston-and-cylinder unit, has a mechanical lock to lock the press in the closed position so that it is not necessary to maintain a high hydraulic pressure to keep the press closed. The mechanical lock may be a set of claws on the hydraulic cylinder to co-operate with a locking ring on the piston rod, with a hydraulic lock cylinder to retract the claws for unlocking, or a lock gate that is introduced into or retracted out of the path of a lock collar on the piston rod by operation of a lock cylinder. The press is first closed with a predetermined high hydraulic pressure that compresses the filter press pack sufficiently for easy movement of the mechanical lock into locking position, and then operation of a lock limit switch automatically stops the hydraulic pump and energizes a bleed valve to reduce the closing pressure to a level at which the press pack compression is relaxed enough to give firm lock engagement.
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