Hey there! As a supplier of Globe Valves, I often get asked about the difference between a rising stem and a non - rising stem globe valve. So, I thought I'd write this blog to clear up any confusion and help you make an informed decision when it comes to choosing the right valve for your needs.
First off, let's talk about what a globe valve is. A Globe Valve is a type of valve used for regulating flow in a pipeline. It has a spherical body with an internal baffle that divides the body into two halves. The flow is controlled by a disc that moves up and down to either block or allow the passage of fluid.
Now, let's dive into the main topic: the difference between rising stem and non - rising stem globe valves.
Rising Stem Globe Valve
A rising stem globe valve is pretty easy to spot. As the valve opens and closes, the stem moves up and down. You can clearly see the position of the valve just by looking at the stem. If the stem is extended out of the valve bonnet, the valve is open. Conversely, when the stem is mostly inside the bonnet, the valve is closed.
One of the big advantages of a rising stem globe valve is the visual indication of the valve's position. This is super handy in situations where you need to quickly tell if a valve is open or closed, especially in large industrial plants with lots of valves. It also allows for easy maintenance and inspection. You can see if the stem is damaged or if there are any signs of wear just by looking at it.
Another plus is that the stem doesn't rotate while the valve is being operated. This means that there's less chance of the packing around the stem getting twisted or damaged, which helps to prevent leaks.
However, rising stem globe valves do have some drawbacks. They take up more vertical space compared to non - rising stem valves. This can be a problem in installations where space is limited. Also, in dirty or corrosive environments, the exposed stem can be more prone to damage from debris or chemical attack.
Non - Rising Stem Globe Valve
In a non - rising stem globe valve, the stem doesn't move up and down as the valve opens and closes. Instead, it rotates to move the disc up or down. The position of the valve isn't as obvious as with a rising stem valve. You usually have to look at a position indicator or rely on markings on the handwheel to tell if the valve is open or closed.
The main advantage of a non - rising stem globe valve is its compact design. Since the stem doesn't extend out of the bonnet, it takes up less vertical space. This makes it a great choice for installations where space is at a premium, like in shipboard applications or in underground pipelines.
Non - rising stem valves are also less likely to get damaged by external factors because the stem is mostly protected inside the valve bonnet. This makes them more suitable for harsh environments.
On the flip side, it can be more difficult to tell the exact position of the valve without additional indicators. And if the position indicator fails, it can be a hassle to figure out whether the valve is open or closed. Also, the rotating stem can cause more wear on the packing, which may lead to leaks over time.
Applications
The choice between a rising stem and a non - rising stem globe valve often depends on the application.
For applications where visual indication of the valve position is crucial, such as in power plants or chemical processing facilities, rising stem globe valves are usually the way to go. Operators need to be able to quickly assess the status of the valves to ensure safe and efficient operation.
In contrast, non - rising stem globe valves are commonly used in applications where space is limited. For example, in offshore oil rigs or in building plumbing systems, the compact design of non - rising stem valves makes them a practical choice.
Other Related Valves
Before we wrap up, I'd like to mention a couple of other types of valves that you might also be interested in. A Gate Valve is another common type of valve used for on - off service. It has a gate - like disc that slides up and down to control the flow. Gate valves are known for their low pressure drop when fully open, but they're not as good at throttling flow as globe valves.
Then there's the Forged check Valve. This valve allows fluid to flow in only one direction and prevents backflow. Check valves are essential in systems where you need to prevent reverse flow, like in pumping systems.
Conclusion
So, there you have it! The difference between rising stem and non - rising stem globe valves boils down to their design, advantages, and applications. If you need a valve with a clear visual indication of its position and don't mind the extra space, a rising stem globe valve is a good option. But if space is a concern and you can work with less obvious position indicators, a non - rising stem globe valve might be the better choice.
If you're in the market for a globe valve or any other type of valve, we're here to help. We have a wide range of high - quality valves to meet your specific needs. Whether you're a small business or a large industrial corporation, we can provide the right valve solution for you. Feel free to reach out to us for more information or to start a procurement discussion. We're always happy to talk about valves and find the best fit for your project.
References
- "Valve Handbook" - A comprehensive guide on different types of valves and their applications.
- Industry standards and specifications for globe valves from relevant engineering associations.