In a piping system, a component that is used to control the flow of the media through the system is known as a valve. There are a variety of types of valves, each having their own features. They include:
Manifold Valves: For pressure instruments they are manual block and bleed manifold valves. These valves are castoff in pressure gauges, system impulse lines, differential pressure, flow plotter and switches. Depending on their types, their functions include pressure isolation, process equalizing, draining and venting and custody transfer. They control oil, water, toxic fluids, chemicals, air, and steam. To mount to an industrial differential pressure transmitter, flanged models are designed.
Instrumentation Ball Valves: It is a form of quarter-turn valve. To control flow through itself, it uses a hollow, perforated and pivoting ball, also known as a “floating ball”. The valve is closed when it is pivoted 90-degrees by the valve handle and is open when the ball’s hole is in line with the flow. They are recommended for industries such as oil, gas, and petrochemicals where long life is required.
Needle Valve: It is a type of valve which has a small port and a threaded needle-shaped plunger. Although it is generally only capable of relatively low flow rates, it allows precise regulation of flow. To gradually open a space for fine control of flow, this valve uses a tapered pin. With the use of a spindle, the flow can be controlled and regulated.
Check Valves: They are two-port valves, which mean they have two openings in the body, one for fluid to enter and the other for fluid to leave. As they do not have any valve handle or stem, they work automatically and most are not controlled by a person or any external control. There are various types of check valves including ball check valves, diaphragm check valves, swing check valves, stop-check valves, lift-check valves, in-line check valves, flow check valves, among others. Cracking pressure which is the minimum differential upstream pressure between inlet and outlet at which the valve will operate is an important concept in these valves.