Valves are an important part of any system or process that consists of fluid. A valve controls and directs the flow as well as the pressure of any liquid within a system. Now, there are a lot of types of valves in piping but the primary basis of their comparison is their motion, linear, rotary or quarter turn.
The globe valve is one of the most common types of valves which has a linear motion. A linear motion valve has only one function, to either start the flow of the fluid or stop it. They use a closure member that cuts the flow by moving in a straight line. In the case of a globe valve, the closure member is a kind of a disc that can be completely removed for the fluid to flow freely or it can entirely close the path to stop the flow completely.
When the valve opens or closes, the disc moves in a perpendicular manner to the seat thus creating an annular space between them. This process makes the globe valve work better than the other common valve, the gate valve, and hence is a bit costlier as well. The right angle contact of the globe valve’s seat ring and the disc makes it leak much less than the other types of valves as well as perform better when it comes to regulating the flow.
Types of Globe Valves and Globe Valve Discs
There are three types of globe valves based on the type of the body they have: Z type, Y type, and Angle type. Globe Valves can be also differentiated on the basis of the bonnet connection they have. There are four types of globe valves based on tha differentiation: Screwed, Bolted, Welded, and Pressure-Sealed bonnet. Each type of globe valve is used in various settings with different temperature and pressure variations.
There are many types of disc arrangements that are available. The most common types are:
- Ball type- They are used in lower temperature and pressure systems to start and stop the fluid’s flow.
- Needle type- They are available in several varieties in order to suit different flow conditions. Needle discs have more throttling power than ball discs.
- Composition disk- They give better shutoff power than the other types.
Globe Valve Applications
There are a lot of industries that use globe valves in their common machinery systems and processes that involve fluid. Here are some typical examples where globe valves are effective:
- Cooling water systems are used by several plants and factories. A globe valve is used in such a cooling system where the flow of the water needs to be regulated.
- Piping systems often have high point vents and low point drains installed in them where globe valves are used to ensure maximum safety and leakage protection.
- They are used in turbine drains, seals and lube oil systems.
- Globe valves are used to regulate fuel oil systems where prevention of leakage is crucial.
- They are also used in boiler vents and drains as well as main steam and heater drains.
