Valves play an important role in many industries by controlling the direction and flow of liquids and gases. They are essential components in plumbing, heating, ventilation, air conditioning, power generation and various industrial processes. This article aims to provide a comprehensive overview of valves, their various types, functions and applications.
Types of Valves
There are many different types of valves which are used for different purposes based on their design and mechanism of operation. Some of the major types of valves are:
Gate Valves
Gate valves are linear motion valves used to start and stop fluid flow. They have a vertically sliding gate that opens and closes perpendicularly to the direction of flow. Gate valves are robust, simple and inexpensive. They are commonly used in pipelines to isolate or regulate flow.
Ball Valves
Ball valves have a spherical disc with a port through the middle. They rotate within the valve body to either align or misalign the port with the inlet and outlet. Ball valves achieve positive shut-off and are widely used for on/off applications in many industries due to their reliable sealing.
Butterfly Valves
Butterfly valves are circular disc shaped valves that rotate perpendicularly to the pipeline about its axis. They find application in large diameter pipelines where flow regulation is needed. Butterfly valves take up less space and are lightweight compared to other valves of similar performance.
Check Valves
Check valves, also known as non-return valves, only allow fluid to flow in one direction and block flow in the opposite direction. They automatically open to permit flow in the forward direction due to fluid pressure and close to prevent backwards flow. Check valves are commonly used in pump lines and pressure vessel safety relief lines.
Control Valves
Control valves are designed to regulate flow by varying the size of the flow passage as per the demands of the process. They play an important role in process control systems by automatically maintaining desired fluid pressures, temperatures, liquid levels etc. Fluid flow is regulated by actuators that position the valve plug/disc in response to a controller.
Applications of Valves in Major Industries
Power Generation
Valves have extensive applications in power plants where they regulate high pressure steam in boilers and turbines. Globe valves are used on steam lines, gate valves isolate equipment during maintenance and check valves prevent backflow in condensers. Valves also control feed water, extraction and admission lines in thermal and nuclear power stations.
Petroleum Industry
Valves control crude oil and natural gas pipelines, refineries, storage tanks and ship loading/unloading facilities in the petroleum industry. From offshore platforms to LPG tankers, valves play a critical role in extraction, transportation, processing and distribution of oil and gas. Ball valves are common in piping networks while gate valves isolate equipment.
Water Industry
In water supply networks, gate valves regulate water flow and pressure in transmission mains while globe valves are deployed in pipe junctions and district metering areas. Check valves maintain flow direction. Butterfly valves are used on large diameter pipes. Valves also control processes in sewage treatment plants, desalination plants and pumping stations.
Chemical Industry
A variety of valves including diaphragm valves, knife gate valves and control valves are extensively used in chemical process industries for dosing, blending, reactor feed/discharge and other process requirements. Their ability to tightly seal and regulate corrosive/abrasive fluids makes valves indispensable in chemical and petrochemical plants.
Heating, Ventilation and Air Conditioning (HVAC)
Heating systems employ zone valves to direct hot water to different parts of buildings based on demand. Globe valves are installed in boilers to regulate water flow. Butterfly valves balance air distribution in HVAC ductwork. Ball valves purge air while servicing equipment. Control valves maintain temperature setpoints in chillers and other equipment.
Get More Insights Here
