Valves are basically devices that control flow through a pipeline. It directs the flow in one or more directions, by opening and closing fully or partially. There are different types of valves which find applications based on their mechanism of operation. The most basic type of valve simply closes to obstruct fluid flow and opens to allow it. There are important components to ensure safety of the operating system.
Valves can be operated using handles, levers, wheels or even pedals. In industrial systems, valves are often operated automatically based on the changes in pressure, volume and temperature. Similarly, valves are automated in boilers and similar equipment where they are internal to the device and cannot be manually manipulated during the application phase.
Types of valves based on operation mechanism
Valves can be hydraulic, pneumatic, manual, solenoid or motor-operated. Many valves are controlled by handles or levers connected to the outside. The position of the handle or lever determines the flow condition through the valve. If it is perpendicular to the position, it is called a quarter-turn. Butterfly, ball and plug valves are this type.
Sometimes the handle of the valve may be replaced by a wheel. In this case the valve is operated by turning the hand wheel to open and close it to regulate flow. This controls the volume of fluid passing through the pipe at a time, based on the degree to which the wheel has been rotated.
Valves can also be operated by electric motors or solenoids that work on electromechanical principles. Another method of operation is using air pressure or pneumatic control, or using hydraulic actuators such as oil or water.
Pilot valves are the control valves that determine the operation and position of various other valves in the system. They can be considered as the managers of the system.
Types of Safety Valves
There are a variety of safety valves available to meet different applications. These are also called relief valves and controls or limit the pressure in a system. The selection is often based on the demand from the valve by the particular industry. Pressure safety Valves such as the nupro valves find a range of operation in connectors and hosing.
Safety valves may or may not be designed for complete shut off. In order to switch off the flow, most valves such as the nupro valve may not have an inbuilt feature and may require a solenoid valve or similar mechanism before it to induce full cut off. The benefit of the nupro valve is mainly that it allows fine control over the flow rate.
Pressure safety valves or PSVs have a manual lever which can be used to activate it in an emergency. Their operation mechanism is normally spring-based. The PSV opens when the pressure rises to a set value and cuts off flow.
The other type of pressure valve is a Safety Valve, which is employed in gas services. They normally open completely and shut out flow entirely. These can be lifted or snapped open. The safety relief valve is often used for gas or liquids. The pressure that is set as the threshold, however applies to only one fluid at a time.
Pilot operated valves offer remote control. This is normally automated and controls several other valves. Vacuum pressure safety valves are used when the pressure of the gas is very small. They normally relieve the static pressure of a gas. Other systems such as the pressure vacuum release valve or low vacuum pressure safety valves are designed around the vacuum pressure valves, and combine the action of a vacuum pressure valve with a relief valve in one place. Nupro valves with pneumatic butterfly valves have circular plates attached to a transverse spindle and mounted inside a pipe and is used to regulate or prevent flow. Visit this site for more information about different types of valves