Understanding About Parts Of A Ball Valve
While contemplating on the brand and type of ball valve to purchase for use in your shut off application or flow control system, be in the know of its various parts. Having an adept knowledge of its parts will give you an idea of how the valve entirely works when it is installed.
1. Body or Shell:
This part is regarded as the principal part of a valve, regardless of its shape and type. It is the part that gives framework to the whole valve because it holds all the other parts intact. It also serves as the pressure boundary of the valve because it is the first line of resistance against the volume and pressure of the liquid flowing through all the pipes connected to it.
This part covers the opening in the valve’s body. It also serves as the second pressure boundary. Valve bonnets are usually bolted and screwed with the body. It is also usually made of the same material as the body to make the whole valve firmer and stronger.
This part is a collection of differentinternal valve parts such as disk, seat, stem and sleeves. Because of these internal parts, the valve can perform basic motions to provide flow control. The disk together with the seat is important in determining the performance of the valve system. In most designs, the disk serves as the third layer of pressure boundary. It can permit and prohibit fluid flow due to its pressure-retaining capacity.
The seat, also called as seals ring provides an interface to where the disk is seated. The seal rings can either be forged within the body by welding or by machine. The stem is responsible for positioning the disk. It connects the actuator and the disk usually though welded joints.
This part works in conjunction with some internal parts located in the valve trim. This part is responsible for running the stem and disk. There are many types of actuator that are available in the market today. Some are handwheels, levers, motors, solenoids, pneumatic operators or hydraulic arms. Most valve manufacturers’ provide a design where the actuator is mounted with the bonnet through a yoke.
This part commonly prevents leaks from the space between the valve stem and bonnet. The valve packing can be made from fibrous materials like flax or some other materials like Teflon. Regardless of the valve packing composition, it should be able to form a seal between the internal parts and the outer valve environment where the stem extends from the valve body. The packing must be properly placed to prevent leaks that can cause further damages to the entire valve system. The packing must neither be too loose nor too tight.
In summary, knowledge of the different parts of a ball valve will give you a generalized idea of how it will work during the entire span after it has been installed by your designated workforce. It will also help you to have a rough estimate of the cost of implementing a flow control system with the use of a ball valve.
Read the selection guide to help you choose the right one for your application.
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