Advantage and Disadvantage of Globe Valve

Globe valve: a valve in which the closure (disc) moves along the center line of the seat. According to this type of disc movement, the change of seat opening is directly proportional to disc travel. Because of this type of valve stem opening or closing stroke is relatively short, and has a very reliable cut-off function. What’s more, the change of valve seat opening and disc stroke is proportional, so it’s very suitable for flow regulation. Therefore, this type of valve is very suitable for cutting or regulating, and throttling.

Advantages of Globe Valve:

1. During opening and closing, the friction between the disc and valve body sealing surface is smaller than the gate valve, so it is wear-resisting.
2. The opening height is generally only a quarter of the valve seat passage, so much smaller than the gate valve;
3. Usually, there is only one sealing surface on the valve body and disc, so the manufacturing process is better and easy to maintain;
4. As the packing is generally a mixture of asbestos and graphite, so the temperature grade is higher. General steam valves are globe valves.

Disadvantages of Globe Valve:

1. As the flow direction is changed after the medium pass through the valve, so the minimum flow resistance of the globe valve is higher than most other types of valves;
2. Due to the longer travel of the replacement, the opening speed is slower than the ball valve.

Conclusion:

The practical size limit for these valves is NPS 12 because the system pressure applied on the globe valves is frequently used to regulate flow. To prevent early failure and provide excellent service, the range of flow control, and pressure drop. Duty must be taken into account during the design of the valve. A valve trim that is specifically designed for high-differential pressure throttling service is necessary. It is transmitted to the valve stem (DN 300). The exception rather than the norm is globe valves bigger than NPS 12 (DN 300).