A sluice is a water channel that is controlled at its head by a gate. For example, a millrace is a sluice that channels water toward a water mill. The terms "sluice gate" and "slide gate" are used interchangeably in the water/wastewater control industry.
A sluice gate is traditionally a wooden or metal plate which slides in grooves in the sides of the channel. Sluice gates are commonly used to control water levels and flow rates in rivers and canals. They are also used in wastewater treatment plants and to recover minerals in mining operations.
A sluice/slide gate is a double-faced valve consisting of an open frame and a slide. Examples of where this type of valve is used include controlling flow (water and wastewater) at openings in tank walls and at ends of pipes. The term "slide gate" has been adopted for use by series of standards (C561, American Water Works Association) C561 is the standard for Fabricated Stainless Steel Slide (Sluice) Gates. This standard was approved in January of 2004.
This standard describes fabricated stainless steel sluice/slide gates with full aperture closure, designed for either seating or unseating head, or both, in ordinary water supply service. The stainless steel gates have non-metallic seat/seals, which may be of self-adjusting design. Some sluice gate manufacturers use ultra high molecular weight (UHMW) polyethelene seat/seals, to allow ease of movement and eliminate friction.
Raising a sluice gate allows water to flow under it. (The term sluice gate
refers to any gate that operates by allowing water to flow under it.) When a sluice gate is fully lowered, water sometimes spills over the top, in which case the gate operates as a weir
Usually a mechanism drives the sluice gate up or down. This may be a simple, hand-operated, 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, which is controlled by the pressure head across it; operation is similar to 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, 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. Occasionally 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.
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.
In the mountains
of New England
, sluices were used to transport logs from steep hillsides to downslope sawmill ponds
or yarding areas. 19th century logging
was traditionally a winter activity for men who spent summers working on farms
was 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
Sluiceboxes are often used in the recovery of black sands
, 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. Typically, the sluices have transverse riffles over a carpet which trap the heavy minerals, gemstones
, and other valuable minerals. The result is a concentrate.