Table of Contents
Valves are provided in the pipelines for various purposes. The main purpose of providing a valve is to control and regulate the flow of water.
1. Types of Valves
The various types of valves commonly used are as follows:
a. Sluice or Gate or Cutoff Valve
These are the commonly used valve to regulate the flow of water through pipelines. These valves are extensively used in the distribution system to shut off supplies. It consists of a disc or circular gate parallel-sided or e shaped in cross-section and Has a nut that slots in with the thread of an operating spindle.
The disc or circular gate, by raising or lowering flow can be regulated or controlled. These valves may be provided in every junction and in a suitable interval of about 150 to 300 m in a straight portion. These valves are operated by rotating the spindle clockwise to close and anticlockwise to open.
b. Reflux (check valve)
This non-return valve allows water to flow in one direction only and the flow in the reverse direction automatically stopped.
It consists of a disc hinged at its top edge provided at the one end in such a way that it opens when the flow is forward and closes if water tends to flow in the reverse direction.
This valve is invariably placed in a pumping main.
c. Safety or Pressure Relief Valve
These types of valves consist of a disc controlled by a spring that can be adjusted to the desired pressure. It is provided to release the excessive pressure from the pipeline and protect the pipeline against the possible danger of bursting due to excessive pressure.
When the pressure in pipelines exceeds the desired pressure, the disc is forced to be lifted up and a certain amount of water flows out from the cross pipe thereby releasing the pressure in the pipeline. This valve is also called an automatic cutoff valve.
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d. Air Relief or Air Valve
In a pipeline, air may enter or entrained air get trapped which may be accumulated at the summit or high points of the pipeline and maybe seriously blockade to flow of water.
It consists of a CI chamber, float, lever, and poppet valve held in the closed position. The chamber is connected to the bolted-on pipe top opening in the crown.
A floating mass and a lever in it are adjusted and when water is under pressure it lowers and the poppet valve is opened to result in the release of pressure.
e. Drain or Scour Valve
These are similar to blow-off valves also known as wash-out valves. They are ordinary sluice valves operated by hand. They are located at the depressions and dead ends to remove the accumulated silt and sand. After the complete removal of silt; the value is to be closed.
2. Advantages of Valve
The advantages of valves are as follows:
a. Easy to control the flow of water.
b. Reduce leakage.
c. Widely applicable.
d. Easy to open and close.
e. Inexpensive to buy.
f. Durable
3. Disadvantages of Valve
The disadvantages of the valve are as follows:
a. Chances of blockage.
b. Needs regular maintenance.
c. Not suitable for all applications.
4. References1. Content Filter & Authenticity Checking Team, Dream Civil International (Our team checks every content & detail to maintain quality.) |
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