A valve is simply a device that directs or regulates flow by opening, closing or partially obstructing passageways. Valves are instrumental in everything from pumping soap out of a dispenser to starting a jet.
You can’t be a pipe expert without being an industrial valve and fitting expert, as well. Without valves, there would be no control of your pipe flow. Here are some of the types of valves and their applications.
Gate Valves
Gate valves, the most common type of valve in the industry, are valves that open by lifting a gate out of the route of the fluid. Gate valves are designed to be fully open or closed; they are regularly used as a block valve for isolating pipe systems.
When a gate valve is open, there is no obstruction in the flow path resulting in very little friction loss. Gate valves are used when a straight-line flow of fluid and minimum restriction is desired.
These can be controlled by a hand-wheel, air-powered diaphragm, electric motor, or a piston actuator.
Globe Valves
Globe valves are used for regulating flow in a pipeline, instead of having the “all or nothing” function of a gate valve. Globe valves regulate by the position of a movable disk (or plug) in relation to the stationary ring seat.
A globe valve may have ports that run straight across or may be pointed at an angle. This type of angled supply valve is commonly used for corrosive or thick, viscous fluids that tend to solidify. Having outlets on an angled supply valve that points downward helps the fluid to drain off to prevent clogging and corrosion.
Needle Valves
The needle valve is essentially a variation of the globe valve used for very fine control of flow. Needle valves contain a slender, tapered plug, as opposed to the globe valve’s larger and less accurate disk.
Butterfly Valves
The butterfly valve is also designed to regulate flow, but with limited control capability. This is a simpler industrial valve and fitting that is easily operated by rotating a handle 90 degrees. The butterfly valve has not generally been thought to give a positive shut-off, however, modern technology has facilitated the assembly of a bubble-tight shut-off.
Check Valves
Check valves, also known as NRVs (non-return valves), permit fluid to flow in one direction only. Their purpose is to prevent backflow. There are several types of “stoppers” that prevent backflow in check valves. Ball check valves and piston check valves operate by requiring a minimum amount of inbound flow pressure; backflow is not forceful enough to lift the ball or piston back up to travel the other direction. Flow in a swing check valve pushes through a hinged flap that only opens in one direction, assuring the fluid cannot travel backward.
Relief Valves
The relief valve, also known as the safety valve, is an industrial valve and fitting installed to set a limit on the amount of pressure in a system. This type of angled supply valve is strictly for preventing over-pressure that could cause damage to the system.