Sluice

Operation

"Sluice gate" refers to a movable gate allowing water to flow under it. When a sluice is lowered, water may spill over the top, in which case the gate operates as a weir. Usually, a mechanism drives the sluice up or down. This may be a simple, hand-operated, chain pulled/lowered, worm drive or rack-and-pinion drive, or it may be electrically or hydraulically powered.

Types of sluice gates

Flap sluice gate

A fully automatic type, controlled by the pressure head across it; operation is similar to that of a check valve. It is a gate hinged at the top. When pressure is from one side, the gate is kept closed; a pressure from the other side opens the sluice when a threshold pressure is surpassed.

Vertical rising sluice gate

A plate sliding in the vertical direction, which may be controlled by machinery.

Radial sluice gate

A structure, where a small part of a cylindrical surface serves as the gate, supported by radial constructions going through the cylinder's radius. On occasion, a counterweight is provided.

Rising sector sluice gate

Also a part of a cylindrical surface, which rests at the bottom of the channel and rises by rotating around its centre.

Needle sluice

A sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam.

The gates of a Guillotine lock work in a way similar to a sluice gate, but most canal lock gates are hinged to swing like doors.

Logging sluices

In the mountains of the United States, sluices transported logs from steep hillsides to downslope sawmill ponds or yarding areas. Nineteenth-century logging was traditionally a winter activity for men who spent summers working on farms. Where there were freezing nights, water might be applied to logging sluices every night so a fresh coating of slippery ice would reduce friction of logs placed in the sluice the following morning.

Placer mining applications

Sluice boxes are often used in the recovery of black sands, gold, and other minerals from placer deposits during placer mining operations. They may be small-scale, as used in prospecting, or much larger, as in commercial operations, where the material is first screened using a trommel or screening plant. Typical sluices have transverse riffles over a carpet, which trap the heavy minerals, gemstones, and other valuable minerals. The result is a concentrate.

Types of material used for sluice gates

Cast Iron

Cast iron has been popular when constructing sluice gates for years. This material is great at keeping the strength needed when dealing with powerful water levels.

Stainless Steel

Stainless steel in most cases is lighter than the older cast iron material.

Fibre-reinforced plastic (FRP)

Rather recently a new technologies such as fibre-reinforced plastic are being used to build sluices. This modern technology has many of the attributes as the older ways while bringing in new attributes such as corrosion resistance and much lighter weights.

Regional names for sluice gates

In the Somerset Levels, sluice gates are known as clyse or clyce.

Most of the inhabitants of Guyana refer to sluices as kokers.

Sinhala people in Sri Lanka who had a harvested rain water based ancient civilization refer to sluices as Horovuwa.