If you’ve ever squeezed the end of a hose pipe to control the flow of water, they your fingers were essentially acting as a valve. At its most basic, a valve regulates, directs or controls the flow of any fluid by opening, closing or obstructing a passageway.
Functions of Industrial Valves
- Stopping flow of fluid
- Starting flow of fluid
- Reducing flow of fluid
- Increasing flow of fluid
- Controlling the direction of flow
- Regulating a flow or process pressure
- Relieving a pipe system of a certain pressure
Regardless of type, valves have the following basic parts –
- Body – the valve body (or shell) is the outer casing of the valve. This is where the fluid flow happens and where other elements of the valve are housed.
- Bonnet – this is the upper jacket which fits on the valve body by being screwed or bolted onto the body. Some valves do not require a bonnet, however.
- Ports – these are the passages which allow the fluid to pass through the valve.
- Actuator – this component moves steam and the disc (or closing) element. It comes in the form of a hand wheel or lever depending on the valve type.
- Disc or closing element – this element is moved to obstruct or regulate the fluid flow.
- Seat – this internal part either forms a part of the body, or is attached to the body, and is the place where the closing member rests during shut-off.
- Steam – the closing element is connected to the steam which transmits the motion from the controlling device to the disc. The force transmitted by the stem is either linear or rotational torque depending on the valve type.
- Gaskets – available in various materials, these make valves leak-proof while also reducing vibrations and noise.
Types of Valves
There a wide range of valves, but here is a selection of the most common ones –
- Ball – the hollowed-out sphere (or ball) sits inside a pipe thereby blocking the fluid flow. The ball swivels to 90 degrees when the handle turns, allowing the fluid to flow through.
- Butterfly – this valve has a disk that sits in the middle of a pipe and swivels sideways for fluid flow or upright to block flow.
- Cock or plug – here the flow is blocked by a cone-shaped plug that moves aside when a lever is turned.
- Gate or sluice – these valves open and close pipes by lowering metal gates across them. Gate valves are generally fully open or fully closed and often used for water flow.
- Globe – very common for water taps, globe valves allow for more or less fluid to flow through. When the lever is turned, the valve screws upward allow pressurised water to flow up the pipe and out the spout. See our range of globe valves
- Needle – used in carburetters and heating systems, the needle valve uses a long, sliding needle to regulate fluid flow precisely.
- Poppet – found in car engine cylinders, poppets are essentially a lid sitting on top of a pipe, lifting every so often to release liquid or gas.
- Spool – these regulate the flow of fluid in hydraulic systems by sliding backwards and forwards in one direction or around a circuit of pipes.
This is a basic outline of the various valves available, as well as their uses, but it is worth getting some expert insight before selecting the valve suited to the job.
Heaton Valves Africa stock, distribute and supply a range of valves for a variety of applications in the to the oil and gas, petrochemical, mining, power, process, product storage and combustion engineering industries.