This is just a direct translation, but also based on your example description. 'zsilip' I would translate as 'sluice value' here, and 'keresztzár' as 'cross lock' or 'cross-locking'.

Alternatively, in certain designs of army knives 'keresztzár' is translated as an 'internal lock', so maybe 'internally locking sluice valve'.

Having said all this, none of these terms appears to be in common usage, so your search goes on.