Top interview question answer about glove valve
Why globe valve used in steam application in place of the ball valve?
Actually nowadays a variety of ball valves are available in the industry. Due to new technology we can’t judge the globe used for steam lines and ball valves can’t. The main reason is that clearance between ball and inside the ball valve body is very less, due the high temperature difference ball material expands and squeezes, and that leads to the leaking problem if clearance is goes exceed, so ball valve is not preferred in steam service. Some reason is also there for the ball valve is not a good choice for steam services; these are below discussed.according to its application of closing Globe valve used for regulating and throttling process where the ball valves are used for isolation. Ball valves are used for clean fluid services and not for moisture content. the ball valves used for gas services in high pressure applications Globe is also used for high pressure and high temperature applications but for clean gases not required, it is used for any applications like liquids in the ball valve in place of disc or ball is to control the flow inside the valves.
Introduction of globe valve
2. Can globe valves be used for isolation?
Globe valves
Yes, Globe valve is also used for isolation purposes and not only for isolation but also for throttling purposes as well. Globe valve is better because some disadvantages are also present with Globe valve like pressure drop, largest space required for installation, not best suited for large bore size and heavyweight as compared to gate valves so before the select the Globe valve check your requirements and make decisions.
3. Where should pressure enter a globe valve?
from the lower side of the body and goes out to the top side, in Z type of valve.
4. What is the symbol for a globe valve?
5. What kind of valve can be used to regulate the flow of fluid?
Globe valve is best suited for regulating the flow of fluid, it is used for highly dangerous and high pressure applications.
6. Is the globe valve unidirectional?
Yes Globe valve is unidirectional, but arrow marking is also present in the body of Globe valve and you can install according to its indications but you can also install Globe in opposite direction but you have faced many issues like leaking, early maintenance, reduced life of valve and high pressure drops
7. What is the difference between a gate and a globe valve?
Difference between a gate and a globe valve
Both valves belong to the linear motion valve family. and used for shutoff and shuton but globe valve also use for throttling purposes.
- Using Gate valve pressure drops very little during disk fully open whereas by using globe valve pressure drop is in large amount due to its inside body construction.
- In the gate valve only disks are used to control the flow inside the body. Whereas in the case of globe valve plug type disks are used to control the flow.
- Manly the Globe is used for throttling purposes whereas the Gate valve is used for isolation purposes.
- The function of both valves are different the constructions of body of a globe valve indicates as a globe shape as shown in figure
- Globe valves are not very well suited where systems may have large pulsations. Sudden pressure rises and pressure drops because these sudden pulsations will tend to damage the trim and the packing. If you are using high pressure applications. It’s also a requirement that the bonnet of the globe valve be quite large so that you’re able to access the trim and the globe valve is heavier than most other valves with the same flow rate capacity.
The gate valve opens slightly by wheel, the amount of flow is not entered inside before the opening and the flow velocity through the valve is very high.
8. Which is better a globe or a gate valve?
Comparison between globe valve and gate valve
- according to its feature applications and uses, in some aspects, gate valves are best and others are for globe valves.
- on the basis of pressure drop gate valve is best suited
- where compression at the base of the throttling globe is better.
- The comparison of installation and construction of body-like light, weight, and easy installation gate valve is better than Globe valve.
- for the big bore application gate is better.
- On the basis of price, gate valves are cheaper than globe valves.
- on the basis of application of steam service line globe is mostly used.
- A gate valve is not used for high pressure applications like steam, mostly globe valves considered for high pressure applications.
9. What does class 150 valve mean?
Class 150
The Class 150 rating valve is used only with class 150 rating piping and is designed according to the ASME 150. The main purpose of the divided class is that it is easy to select the appropriate materials for equipment like valves and piping for suitable applications. with the help of classification of valve flanges, class is easy to select and understand about what types and what material to be used. For what types of applications and fluid services? if the pressure is more in service to service the class has also increased to 300 or more.
10. Why do globe valves have a higher pressure drop than gate valves?
Globe valve has higher pressure drop than gate valves and many other types of valves due to inside body construction. because the body of the Globe valve for fluids flow is not in a straight line like the gate valve body. The body construction inside is sometimes a type y type and angle. due to the flow of the liquids that goes through bend inside the body like Z, Y, and angle that is the reason for pressure drop, throttling is also a big reason for pressure drop because Globe valve is also used for throttling purposes.
