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Sluice

Sluice is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sluice rather than just read about it. In short: A sluice ( SLOOS) is a water channel containing a sluice gate, a type of lock to manage water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates.

Sluice — main illustration
Sluice — illustration

Key takeaways

  • Sluice belongs to engineering; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Sluice to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Sluice from memory before moving on to harder problems.

Reference excerpt

A sluice ( SLOOS) is a water channel containing a sluice gate, a type of lock to manage water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates. Sluices are used for channeling water toward a water mill, including for transporting logs from steep hillsides. Different terms are used regionally for sluices; the terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry.

Etymology The term "sluice" originates from the Middle English word scluse, which derived from the Old French escluse (modern French: écluse). This, in turn, came from the Late Latin exclusa, a shortening of aqua exclusa, meaning "excluded water" or "a shut-off water channel". The Latin exclusa is the feminine past participle of excludere ("to shut out, exclude"), from ex- ("out") and claudere ("to close").

Regional names In the Somerset Levels, sluice gates are known as clyse or clyce. Most of the inhabitants of Guyana refer to sluices as kokers. The Sinhala people in Sri Lanka, who had an ancient civilization based on harvested rain water, refer to sluices as Sorowwa.

Description

A sluice is a water channel containing a sluice gate, a movable gate allowing water to flow under it. Sluices are a type of lock to manage the water flow and water level. 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.

Basic design

Sluice gates are one of the most common hydraulic structures used to control or measure the flow in open channels. 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 the designing of sluice gates are:

Types

Fan gate (Dutch: waaiersluis) This type of gate was invented by the Dutch hydraulic engineer Jan Blanken in 1808. He was Inspector-General for Waterstaat (Water resource management) of the Kingdom of Holland at the time. 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. 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. 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. (See also Log driving and Timber rafting) Mill race A mill race, leet, flume, penstock or lade is a sluice channeling water toward a water mill. Needle sluice A sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam. 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. Vertical rising sluice gate A plate sliding in the vertical direction, which may be controlled by machinery.

Gallery

See also Canal List of canals by country Hydraulic engineering Control lock Gatehouse (waterworks) – An (elaborate) structure to house a sluice gate Floodgate Lock Rhyne, drainage ditch in coastal areas Sluice related family names Zijlstra – A Dutch name referring to one who lives near a sluice Van der Sluijs – A Dutch name originating from the Sluice

References

Further reading Crittenden, H. Temple (1976). The Maine Scenic Route. McClain Printing. Moody, Linwood W. (1959). The Maine Two-Footers. Howell-North. Cornwall, L. Peter & Farrell, Jack W. (1973). Ride the Sandy River. Pacific Fast Mail.

External links

Soar Valley Sluice Gates Salt/Fresh water separating Sluice Complex (Part of DeltaWorks)

Illustrations

Sluice: A sluice gate
A sluice gate
Sluice: The important parameters in designing sluice gates.
The important parameters in designing sluice gates.
Sluice: 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.
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.
Sluice illustration
Sluice illustration

Worked examples

Example 1 — a first encounter with Sluice

Start with the simplest possible case. Write down what Sluice claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sluice before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sluice ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sluice

In research
Sluice appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Sluice in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Sluice is common in secondary-school and first-year university syllabi. It links to neighbouring topics Canals, Dutch words and phrases, Hydraulic engineering, so understanding it makes those chapters shorter.
In everyday life
Look for Sluice outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sluice in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Sluice means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Sluice out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sluice in simple terms?

A sluice ( SLOOS) is a water channel containing a sluice gate, a type of lock to manage water flow and water level. There are various types of sluice gates, including flap sluice gates and fan gates.

Why does Sluice matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sluice?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sluice.

Tags

  • Canals
  • Dutch words and phrases
  • Hydraulic engineering
  • Water transport infrastructure

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