There are a wide variety of valves available on the market today with different functions and purposes and made of different materials. They are all mechanical in operation and control how fast the flow and how great the pressure of a liquid or gas is within a system. Valves form a vital part of many different types of machinery.

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Varying a great deal in size, function, design and operation, valves are versatile items that are part of many types of machinery used on a daily basis. Sometimes known as regulators, there are a number of different classifications for industrial valves.

How valves control flow

Systems that don’t need the flow throttled can use stop/start valves; as their name suggests, these simply allow the flow to be stopped and started as required. Where there is a need to control the speed and capacity of the flow, it is necessary to use a throttle or control valve instead.

In addition, there are two methods of control that can be implemented in industrial valves. The first method is where the flow can be controlled via linear motion whereby the valve opens and closes using a disc, slat or flexible diaphragm that moves in a straight line to operate. Linear valves can be used to push a plug against an opening to stop the flow, to slide a plug across an opening to stop the flow, or to move a flexible diaphragm into the flow to stop it.

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The second method of control is using a rotary motion. In this case, a disc or ellipse is rotated into and out of the flow in an angular or circular method. A common type of rotary valve is the quarter-turn valve, whereby the valve will be completely shut off or completely opened with a 90-degree turn.

Parts of a valve

Valves vary in size type and function; however, they all essentially have the same seven components that enable them to function. These are the body, the bonnet, the trim, the disc and seat, the stem, the stem packing, the yoke, and the yoke nut.

There are many types of valve and many uses. They have a long history in industrial design and manufacture and are essential components of many types of machinery.