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Concrete Doors and Vaults (Pty) Ltd

Ver. 043

Sliding Lid No-Gap Lid Roll-Open lid

Roll-Open Lid

1. Screw Lid

2. No-Gap Lid

3. Sliding Lid

 A customised tool is inserted into an access tube and turned to screw the lid out of the seat. The lid is now turned through 90 degrees, the tool is partially withdrawn, and the lid is rolled away on tracks. (It is opened and closed in the same way as the lid of the Screw-lid vault). In this way relatively large and heavy lids may be opened without requiring a crane. Suitable for reservoirs, valve-chambers, etc.


This lid is supported by the roof-slab, and once unlocked, slides open with relative ease. Suitable for valve chambers where a large opening is required for servicing the valves etc.

Four concrete lids are discussed here, all having extremely robust locking mechanisms.


4. Roll-Open Lid

Suitable for relatively large manholes in valve chambers where quick and easy access is required, and where the opened lid must be clear of the manhole. Once the custom tool has unlocked the lid, the lid may be rotated through 90 degrees.

The ‘no-gap lid’ fits into a slab with practically no gap between the lid and the slab. (The lid has inwardly sloping sides while the slab has outwardly sloping sides, and they therefore fit snugly together in male-female fashion.) The absence of a gap prevents chisels, picks, and crowbars from prying the lid open. For new valve chambers the slab becomes the roof of the structure. For existing valve-chambers with existing roof-slabs the slab may be made substantially smaller, just slightly larger than the existing manhole.  In either case the locking mechanisms below the lid prevent it from being lifted out of the slab in the absence of an opening tool.


Concrete Lids

No-Gap Lid

Screw lids

Screw Lid

Sliding Lid

    Press on the links above for a 1-page PDF

We protect your sub-stations, pump houses, pump stations, control rooms, valve chambers, sewer plants, boreholes, generators, transformers, control panels, valves and cathodic equipment with concrete doors, vaults, lids and vents.

Protect and secure your structures and equipment with our extreme, high-protection products made with chisel proof Y12 rebar reinforcing and 60MPa concrete, offering extreme protection.