A valve is a mechanical device used for controlling pressure and flow inside a process or system. They are important parts of any piping network that it is used to convey vapours, gases and liquids. There are different types of valves used for different applications and these include gate, ball, plug, diaphragm, control and pinch valves to name just a few.
Each different valve type comes in a range of models with specific features and varying functional capabilities. Some involve self-operation; others are manual and some come with a hydraulic or pneumatic actuator.
Here are some of the functions of a valve:
- Beginning and ending a flow of material
- Lowering or increasing a flow of material
- Controlling the route of that flow
- Regulating the pressure or flow of a process
- Relieving pressure inside a pipe system
Valves are used for a variety of industrial applications and all will be used for one or more of the above functions. It is important that a valve is used for the right function and constructed from the correct material to handle the type of liquid it is designed for.
It doesn’t matter what application it is used for; all valves share the same characteristics. They consist of different parts such as a body, bonnet, trim and actuator.
The body – Also known as the shell, this is the primary part of a pressure valve. It is the main element that holds all the other parts together. As the first boundary, it must resist pressure loads from the pipes that connect to it and receives these pipes through bolted, threaded or welded on joints. For a place to buy a Brass Ball Valve, visit a site like https://www.orseal.com/products/ball-valves/
The bonnet – This is the covering for opening found in the body. It is the second major element of a pressure valve. There are many designs and materials available for different functions. It is made from the same material as the body.
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The Trim – This is the removable internal section that includes things like the valve discs, seats, bushings and springs. A trim’s performance depends on the seat and disk and their position with each other. They can be made from a wide variety of materials depending on what is flowing through the system. When considering trim type, it’s important to think about flow rate, velocity, pressure, composition of liquid and temperature to determine which material is the most suitable.
Disk and Seat – The disk is the element that allows the flow and affects its speed. With a ball valve, the disk is the ball. This is the third most important part of the valve and is considered a component very much related to pressure. Seats are also known as seal rings and provide a place for the disk to sit. With a gate valve, there are two seats, one for the upstream side and one for the downstream.
Valve Stem – This is the section that provides movement for the disc, ball or plug for the opening and closing of the valve. It is joined to the lever or actuator at one end and the disc on the other. There are 5 different types of valve stems.