What is Gate Valve and Why Do We Use Them?

Water channel controlled at its head by a gate

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"Sluiced" redirects here. For the linguistic phenomenon, see sluicing

A sluice gate

A sluice ( SLOOS) is a water channel containing a sluice gate, a type of lock to manage the water flow and water level. It can also be an open channel which processes material, such as a river sluice used in gold prospecting or fossicking. A mill race, leet, flume, penstock or lade is a sluice channeling water toward a water mill. The terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry.

Operation

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"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. A flap sluice, however, operates automatically, without external intervention or inputs.[citation needed]

Types of sluice gates

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Plan view of a fan sluice (flow from bottom to top of diagram) (Note: gray areas are the inner empty spaces in which water can flow.)
1: Tube connecting the chamber to the high water side of the sluice
2: Gates to regulate the water level in the chamber. Only one gate may be opened at a time
3: Tube connecting the chamber to the low water side of the sluice
4: The chamber in which the water level can be controlled
5: Door with larger surface
6: Door with smaller surface.
When the tube to the high water level side (1) is opened, the water level in the chamber (4) will rise to this same level. As there is no height difference across the larger gate (5), it exerts no force. However, the smaller gate (6) has a higher level on the upstream side, which exerts a force to close the gate (counter-clockwise). When the tube to the low water side (3) is opened, the water level in the chamber (4) will fall, and a force will be exerted on the large door (5) in the opening direction (clockwise). The pressure difference on both doors is the same, but the surface area is not. This ensures that the opening force (on 5) overcomes the closing one (on 6), which causes the gate to turn clockwise and open.

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.

Fan gate

(Dutch: waaier sluis) This type of gate was invented by the Dutch hydraulic engineer Jan Blankennl]Waterstaat (Water resource management) of the Kingdom of Holland at the time.[1] The Fan door has the special property that it can open in the direction of high water solely using water pressure. This gate type was primarily used to purposely inundate certain regions, for instance in the case of the Hollandic Water Line. Nowadays this type of gate can still be found in a few places, for example in Gouda. A fan gate has a separate chamber that can be filled with water and is separated on the high-water-level side of the sluice by a large door. When a tube connecting the separate chamber with the high-water-level side of the sluice is opened, the water level, and with that the water pressure in this chamber, will rise to the same level as that on the high-water-level side. As there is no height difference across the larger gate, it exerts no force. However the smaller gate has a higher level on the upstream side, which exerts a force to close the gate. When the tube to the low water side is opened the water level in the chamber will fall. Due to the difference in the surface areas of the doors there will be a net force opening the gate.

The important parameters in designing sluice gates

Designing the sluice gate

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Sluice gates are one of the most common hydraulic structures [2] used to control or measure the flow in open channels.[3] Vertical rising sluice gates are the most common in open channels and can operate under two flow regimes: free flow and submerged flow. The most important depths in designing of sluice gates are:

Y U {\displaystyle Y_{U}}

Y G {\displaystyle Y_{G}}

Y m {\displaystyle Y_{m}}

Y J 1 {\displaystyle Y_{J1}}

Y J 2 {\displaystyle Y_{J2}}

Y D {\displaystyle Y_{D}}

Logging sluices

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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.[4]

Placer mining applications

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Miners working a small sluice on Lucky Gulch, Alaska

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 sometimes screened using a trommel, screening plant or sieve. Traditional sluices have transverse riffles over a carpet or rubber matting, which trap the heavy minerals, gemstones, and other valuable minerals. Since the early s more miners and prospectors are relying on more modern and effective matting systems.[citation needed] The result is a concentrate which requires additional processing.

Types of material

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Aluminium

Most sluices are formed with aluminium using a press brake to form a U shape

Wood

Traditionally wood was the material of choice 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

In most cases, stainless steel is lighter than the older cast iron material.

Fibre-reinforced plastic (FRP)

In modern times, newer materials such as fibre-reinforced plastic are being used to build sluices. These modern technologies have many of the attributes of the older materials, while introducing advantages such as corrosion resistance and much lighter weights.

Regional names for sluice gates

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In the Somerset Levels, sluice gates are known as clyse[5] or clyce.[6][7]

Most of the inhabitants of Guyana refer to sluices as kokers.[citation needed]

The Sinhala people in Sri Lanka, who had an ancient civilization based on harvested rain water, refer to sluices as Horovuwa.[8]

Gallery

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• A small wooden sluice in Magome , Japan, used to power a waterwheel

• Sluice gates near Henley , on the River Thames

• The Korenbrugsluice in Gorinchem is a fan sluice

See also

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References

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Further reading

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• Crittenden, H. Temple (). The Maine Scenic Route. McClain Printing.

• Moody, Linwood W. (). The Maine Two-Footers. Howell-North.

• Cornwall, L. Peter & Farrell, Jack W. (). Ride the Sandy River. Pacific Fast Mail.

A gate valve is a device used to stop and start the flow of liquid and isolate sections of a water supply as required. Sometimes referred to as a sluice valve, there are many different types of gate valves suitable for various applications in utility distribution, industrial and HVAC pipeline settings. Lets take a look at what a gate valve is used for, the differences between the most common types, and the things to consider when specifying a gate valve.

WHAT IS A GATE VALVE?

A gate valve is a type of linear valve used to isolate areas of a water supply. As the name suggests, it acts like a gate that shuts off the flow and opens it again when needed.

Gate valves work via a gate or wedge that lifts (opens) or lowers (closes) into the path of the flowing liquid. Motion is produced by an actuator that is connected to the stem of the gate, which may be manual, electrically, pneumatically or hydraulically powered. They may have a rising stem, meaning it is fixed to the gate, or a non-rising stem, where it is fixed to the actuator and remains within the valve body. The latter is most commonly used in the waterworks industry and is suitable for underground applications where there is limited vertical space. 

Gate valves may also sometimes be referred to as stop valves, line valves, wedge gate valves and sluice valves, but they are not to be confused with sluice gates or penstocks. These are altogether larger devices used to severe the flow of sewage and water in treatment plants and drainage systems, etc.

WHAT IS A GATE VALVE USED FOR?

A gate valve is commonly used for isolation duties within potable water, wastewater, sewage and fire main applications. They may be used during maintenance tasks and repair works, as well as being deployed in new installations.

There are many different types of gate valves to suit different applications. Some of the most common designs include wedge gate valves, parallel gate valves, knife gate valves, and rising/non-rising stem gate valves. Generally speaking, you can classify gate valves in three different ways:

• According to the disk type - e.g. taper wedge vs flexible vs split/parallel disk gate valves
• According to stem movement - rising stem vs non-rising stem gate valves
• According to bonnet joint - screwed vs bolted vs welded

The best type to deploy will very much depend on what the gate valve is used for. For example, metal seat valves use a non-ferrous metal face, making them ideally suited to wastewater and sewage applications. When isolating water and clean neutral fluids, resilient seated gate valves provide the ideal solution and work using a rubber encapsulated wedge. Meanwhile, knife gate valves are ideal for handling dense fluids and dry bulk solids. Most gate valves deployed in the waterworks industry have non-rising stems, also referred to as inside screw, meaning the stem remains within the body of the valve.

T-T Flow offers a wide variety of gate valves designed to British and European Standard, with many different options to suit differing applications.

For more information or to discuss your requirements, speak to our expert team on +44 (0) .

Sluice - Wikipedia

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