Design Features

Structural members

The design of all sluice gate structural members complies with the requirements of  DIN Spec. 19704, and under full head conditions there are ample margins of safety over the yield and ultimate strengths of the materials used. In addition, deflections are calculated to be less than those allowable for the type of seals employed.


Sluice gates are fitted with Neoprene music-note ("J" type) seals, whilst channel gates have Neoprene angle ("L") type. These bear against the frame surfaces, and give excellent sealing, as the higher the pressure, the greater the force pressing the seal against the frame, and the more effective the sealing action.

If, for any reason Neoprene cannot be used, metal to metal or thermoplastic seals can be provided.

For high off-seating pressures, and for metal or thermoplastic seals, gates are fitted with adjustable wedges to ensure positive contact between seal faces.

Leakage rates

Gates are designed for minimal leakage, and in practice are often found to be drop-tight. However the permissible leakage rates as laid down in AWWA Spec. C 501, which are ± 1,24 litres per minute per metre of seal for seating pressures, and ± 2,48 l.p.m. per metre for off-seating pressures up to 6m, are guaranteed maxima.

NOTE : Correct installation is essential if these rates are not to be exceeded.

Bearing strips

Hydraulic thrust is taken on low-friction H.D.P.E. strips fitted to the gate, and which slide on the frame as the gate moves. These strips are sized to give low bearing loading, resulting in long life and easy operation. They are also fitted to the larger sizes of channel gates for the same reasons.

Operating gear

For manual operation, handwheel diameters and gearbox ratios are matched to spindle sizes and thread pitches, so that the time required to stroke the gate is kept to a minimum, at the same time limiting handwheel rim effort to normal acceptable levels of between 100 and 150 N.

If gearing is necessary, bevel or combination bevel / spur gearboxes are used.


Spindles are sized in accordance with calculated tensile and compressive loads which will be imposed while opening and closing the gate, and spindle guides are spaced so that buckling of the spindle under compression does not occur.

Cover tubes

Spindle cover tubes can be fitted if desired. If visual indication of gate position is required, the cover tube would be supplied in clear PVC, but steel or stainless steel, being more robust, is recommended wherever possible. The design of the handwheel boss allows a cover tube to be fitted at a later stage, if it is subsequently found to be necessary.

Channel gate headframes

We supply two types of headframes for channel gates. The first comprises integral head and embedded sections, whilst the second, the upper piece is bolted to the embedded frame, which facilitates transport, and allows the lower portion to be installed in the slots prior to the balance of the equipment.

Steel Stop Gate

4m wide x 2,6m high mild steel stop gate for 13m unseating head
( Supplied to Umgeni Water for Inanda Dam Intake )