Valve is the mechanical device that helps in controlling the flow of pressure and fluid within the process and system. Valve stem leakage is controlled properly by compressing the packing around the system. Each type of valve is designed so that it could meet the specific needs. Some of the valves are capable of throttling the flow and others can only stop the flow.
Valves providing major functions
Valve provide many functions and that includes:
1. Stopping and starting flow that is based on the valve state
2. Regulating pressure and flow with in the piping system
3. Controlling and looking after the flow direction with in the piping system
4. Throttling the rates of flow with in the piping system
5. Helps in improving the safety through relieving vacuum and pressure in the piping system.
Valve functions and its basic parts
Regardless valve functions all kind of valves have the basic parts:
1. The body
The body is also called the shell. It serves as the primary pressure of the boundary valve. It serves as the principal element of the valve because it is the framework that holds everything together. The first pressure, the body of the valve, resists fluid and it loads connecting pipes.
The covering of the opening in the valve body is called as bonnet. The body is splitted into 2 sections that bolt together. Like valve bodies bonnet vary in many designs. Some bonnet functions simply as valve covers. This part is the second principle boundary of the valve. It is forged or cast of the same material and it is connected to the body by welded joint, bolted and threaded.
The internal elements of the valves are referred to as the valve’s trim. This trim includes seat, stem, disk and sleeves that are needed to guide the stem. A valve performance is dependent on the seta interface and on disk. The relation of the disk position is with the seat.
The actuator operates the disk and stem. An actuator is a manually operated hand wheel. Motor operator, solenoid operate and hydraulic ram. The actuator is supported by the bonnet and a yoke is mounted with the bonnet to support the actuator.
Most valves use some form of packing to prevent leakage from the space that is between the bonnet and stem. Packing is commonly a fibrous material and another compound that forms a seal. Valve packing is properly compressed and helps in preventing fluid loss and damage to the valve stem.
Valves play an important part in the piping system. It means that they play a key role in the industries. In the gas and oil industries and other industries the function of the valve is to control guide, flow rates and refining process. The valve helps in starting and stopping the fluid flow and helps in controlling the direction of low. A multitude of the types of valves and designs accommodate a good variety of many different kinds of valve applications.