What is a globe valve?
A globe valve is the type of valve which helps in controlling the flow of fluid through a plug or a disk. The globe valve is named as globe valve because of its spherical body with two halves. These valves play a great role in regulating the fluid flow. The plug connects the disk with the stem and this stem is then connected to the hand wheel. These globe valves come in many sizes and in many shapes depending on the designs.
Types of globe valves
To meet the vast range of working duties at the lowest cost and with more variations of globe valves are designed. There are 3 most important types of globe valves that are used for industrial purposes.
· T Type (Tee pattern globe valve)
Globe valves provide the lowest flow coefficient and an extreme high pressure drop. In this throttling services globe valves are used much. If the throttling is required and pressure drop is not a much concern the T type globe valve is an extremely good choice.
· Y Type globe valve
Globe valves of Y type can be cracked and they are open for long periods without having severe erosion. They offer very low flowing resistance and for startup operations Y type globe valves are very much used.
· Angel Type globe valve
Angle globe valve is a new globe valve whose inner and outer are at each other. The basic design of this valve is similar to the globe valve but they have few differences in the fluid flow. The fluid has made 90 degrees and these valves are used in lines where the pressure drop and the pipe construction is hard.
Types of globe valves depending on the body connections
Based on the body bonnet connections the following types of globe valves are available:
· Bolted bonnet
These are most widely used and they are very popular. They need a bonnet joint sealing and a gasket for the body.
· Screwed bonnet
They had a very simple design and they are not much expensive
· Welded bonnet
They are very light weight and they are very popular where no disassembly is needed.
· Union ring bonnet
A separate union ring is needed and they hold the bonnet to the valve body. This type of globe valve construction is very limited to 3 inch in size.
· Flanged bonnet
This type of globe valve increases in pressure and becomes bulky and heavy. They are designed for any size and for any operating pressure.
· Pressure seal bonnet
These pressure seal bonnets are used for very high pressure application and here this type of globe valve is used mostly.
Advantages of globe valve
1. Better shut and good as compared to the gate valves
2. East to repair as the disk and the seat can be function from the top of the valve
3. These are usually operated by the automatic actuator.
Disadvantages of globe valve
1. Faces discontinuous and obstructions in the flow path that leads to high loss
2. More heavier than other valves of the same pressure
3. Much costly as compared to the gate valves.