Gate Valve 101: A Beginner's Guide
Whether you are starting a career in plumbing or mechanical engineering, it is essential to know the different types of valves. When compared to other valves, gate valves are widely used in numerous applications. However, in this guide, you will learn about the definition of gate valves, their operation, advantages, disadvantages, and common applications. So, let’s begin.
What is a Gate Valve?
The function of a gate valve is to control the flow of a fluid, gas, or steam. This happens when the gate or wedge is raised above the path of the fluid. These valves are basically designed to be either completely open or completely shut. However, they are not suitable for throttling applications.
The structure of a gate valve is simple. It has a body, a gate/disc, a stem, a bonnet, and an actuator or hand wheel. As we open the valve, the gate is raised, enabling the fluid to pass completely through it. Just like this, as we shut the valve, the gate comes down, and it ceases the flow of liquid entirely.
Gate valves are mostly made from strong materials such as:
Stainless steel
Brass
Bronze
Cast iron
These materials are appropriate for high-pressure and extreme-temperature substances. Due to their simple design, gate valves are used in numerous tasks.
How does a Gate Valve Work?
The system of a gate valve is quite simple. When we turn the actuator, it rotates the stem, which is threaded. As the stem is rotated, the gate is either raised or lowered in accordance with the direction of the turn.
When the gate valve is opened, the gate is fully drawn back into the bonnet. This enables the fluid, gas, or steam to flow through the valve’s internal side without any restriction. This action creates minimal pressure drop and enables complete flow through the valve.
When the gate valve is shut, the gate creates a tight seal against the seats inside the valve body. It blocks the liquid flow completely. However, the seal created by the gate is typically quite robust.
Gate valves are not ideal for instant functioning, as their gate slides slowly up or down to open or shut them. Therefore, you cannot partially open or close the gate valve to control the flow of liquid, gas, or steam. Otherwise, it can cause the valve to vibrate and create strange sounds, and sometimes damage its internal components. This is the reason why we use gate valves to either completely open or shut them.
The Pros and Cons of Gate Valves
Like all other mechanical devices, gate valves also have their pros and cons. Therefore, if you want to use them, it is very pivotal for you to know the benefits and disadvantages of them in advance.
Pros
· Full Flow Capability: When fully open, gate valves do not significantly restrict the flow. It can minimize energy consumption in pumping systems.
· Phenomenal Shut-off Capability: Gate valves create a super-tight seal. They are superb for applications where separation is crucial.
· Longevity: Their robust materials make them very long-lasting.
· Bidirectional Flow: Gate valves have the ability to deal with the flow of liquid, gas, and steam from both directions.
· Cost-Effective: especially in larger diameters, gate valves are more budget-friendly compared to other types of valves.
Cons
· Lazy Operation: To raise or lower the gate in the gate valves, one needs to turn the actuator multiple times. This makes the gate valve operate slowly.
· Not for Throttling: Gate valves are not intended to regulate flow. Why? Because a half-opened can damage its internal parts.
· Large Size: Due to their large size, they require a considerable amount of space to accommodate them.
· Upkeep Problems: In some applications, deposit buildup can prevent proper sealing, demanding frequent upkeep.
Comparison of Gate Valves and Other Common Valves
When making the decision to buy a gate valve, it is crucial to understand the differences between it and other common valves.
· The Comparison of Gate Valves and Ball Valves: Ball valves offer rapid operation and tighter sealing, especially for high-pressure systems. While gate valves are cost-effective in large diameters, they have a lower pressure drop when fully open.
· The Comparison of Gate Valves and Globe Valves: Globe valves are better for throttling and regulating the flow of fluids, gases, or steam. While gate valves are best for fully opening and shutting them. Globe valves typically create a higher pressure drop due to their design.
· The Comparison of Gate Valves and Butterfly Valves: Butterfly valves are generally smaller and lighter than gate valves. These two qualities make them ideal for installation in tight and congested spaces. However, their seal is not as tight as gate valves and is less appropriate for high-pressure fluids.
Each valve has its own unique qualities. However, you must decide which valve is best suited for each application.
Where You Will Find Gate Valves
Gate valves are used in many places. However, here are some places where gate valves can be found:
· Gate valves have a tight seal, which is why they are commonly seen in municipal and residential water areas.
· In both up and down directions, gate valves control the flow of crude oil, natural gas, and filtered products.
· Gate valves play a crucial role in managing the flow of steam, cooling water, and other fluids, which are essential for power generation.
· Gate valves are also seen in chemical plants. The reason behind this is that gate valves can handle high pressure and corrosive substances.
· Gate valves can be found in fire sprinkler systems.
· Ships and offshore platforms use gate valves for fuel, ballast, and bilge systems. This is because they are reliable in harsh environments such as the sea.
Other Places to Find Gate Valves:
· Food and drinks processing
· Pharmaceuticals
· HVAC systems
Conclusion
Gate valves may seem like simple valves, but they are highly useful in a wide range of applications. Regardless of the purpose for which you are using them, it is crucial to understand everything about them first.
Their super-tight seal makes them an absolutely amazing option where complete blockage of fluids is required. However, their longevity and cost-effectiveness make them a perfect option for many applications.
When you have complete knowledge about gate valves, you can make the most of them in your tasks. However, gate valves are an excellent choice for applications where you want the valve to fully allow or block the flow of fluid. In short, gate valves can do wonders beyond your imagination. Therefore, purchasing a gate valve is a wise decision.
