What is meant by Valves?

Valves are devices that regulate flow and pressure in a system or process. They are a very important component of a piping system that carries liquids, gases, steam etc. What additional explanation is meant by Valve? A valve is a device that serves to drain some or all of the liquid that will pass through it. Or in another explanation, the valve can also be called a mechanical switch that can turn on and turn off the pipe or increase the amount of liquid, gas or steam flowing through the valve.

How obvious is the valve?

Valve category

Various types of valves are available: gates, globe, plugs, balls, butterflies, checks, diaphragms, cubits, pressure relief, control valves, etc. Valve gate, globe valve, plug valve, ball valve, butterfly valve, check valve, diaphragm valve, pinch valve, pressure relief valve, valves control, Safety Valve, Needle Valve and many other types of valves. Each type of valve that already exists above, each has a different model of features and functions as well. Some valves are self-operated while others are manual or with actuators or pneumatic or hydraulic operated.

Example of several functions of the valve:

  • Stop and start flowing
  • Reduce or increase flow
  • Control the flow direction
  • Restore pressure flow or process
  • Lighten the pipe system from certain pressures




There are several designs and types or models of valves, which are quite diverse for industrial applications. All agree to one or more agree to the above. Valves are expensive items, and it is important that the correct valve is determined for its function, and must be made from the correct material for process fluids. Related to the type, all valves have other basic parts such as: body, engine hood, trim (internal elements), actuator, and packing. The base of the valve is illustrated in the following figure.

Valve body

The Valve body, sometimes called a shell, is the main valve of pressure. He works as the main element of the valve assembly because it is the work that unites all parts. The valve body of each component has a special function and is made in different materials according to its function.

Bonnet valve

The cover for the body opening is the hood, because that is the second limit of the pressure valve. As offered by the valve body, the hood is available in many designs and models. This hood has a function as a cover on the valve body, thrown or forged from the same material as the body. In all cases, attach the engine hood when considering the pressure limit. This means that the welded connection or bolt that connects the engine hood to the body is the pressure retaining part. The valve cap is only a small part of the valve needs, but it can also be a cause of most, too. While for the engine hood itself, it also has complexity as well as when making valves, increasing valve size, and representing most valve costs. The second bonned is also one of the potential sources of leakage.

Cut the valve

The internal parts of the removable and replaceable valves that come into contact with the flow media are collectively referred to as VALVE TRIM. These parts include mounting valves, discs, glands, spacers, guides, bushings and internal springs. Valve body, engine hood, packing, etc. which also come in contact with flow media are not considered as valve trims. Valve trim performance is determined by the interface of the disk and seat and the relation of the position of the disk to the seat. Because of the trim, basic movements and flow control are possible. In the trim design of rotational motion, the disk glides tightly past the seat to produce changes in flow openings. In the linear motion trim design, the disk is raised perpendicular to the seat so that a circular hole appears.

Valve trim parts can be made from various materials due to the different properties needed to withstand different forces and conditions. Busing and packing glands do not experience the same strengths and conditions as do discs and valve seats. Flow-medium properties, chemical composition, pressure, temperature, flow rate, speed and viscosity are some important considerations in choosing the appropriate trim material. The trim material may or may not be the same material as the valve body or hood.