Gate Valves

Gate valve is a valve designed to fully open or fully close by using a gate or wedge type disc. The purpose is mainly for blocking fluid flow. The disk moves perpendicular to the flow while fluids start and stop in the piping system.

It requires very little space along the pipe axis for gate valve to restrict the flow of fluid. Gate valve operation performs in either clockwise to open (CTO) or clockwise to close (CTC) rotating motion of the stem and hand wheel. Main components of a gate valve are its body, seat, wedge, stem, gasket, hand wheel and bonnet. 

Product Specifications

​For more information on the individual product specifications, please click on the links below:

What are gate valves

​1. How do gate valves work? ​​​​ ​​2. What is a gate valve used for?

​A gate valve is the most commonly used for process plant application as it is a linear motion valve used to control the fluid flow. The valve can be either in fully opened or fully close position. The gate valve disc is completely removed from the flow when the gate valve is at fully opened position. A typical gate valve has no blocking in the flow path. Thus, resulting in a very low pressure loss and a free bore is created. When the valve is fully closed, a 360° surface contact is required between the disc and seats in order to perform proper sealing. 

It is not applicable as control or regulating valves due to the accuracy of flow control is not achievable. The high velocity of the flow in the partially opened valve is not encouraged. It may cause erosion to the seating surface and disc which will next lead to vibration and noise. 

​There are different types of body gate valve as per below: 3. What is a bonnet on a valve? ​4. What are different types of gate valves?

• Solid taper wedge: The most common and widely used disc type gate valve because of its strength and simplicity. A valve with solid wedge can be installed in any position and it is suitable for all type of fluids. However, it does not compensate in aligning to changes in seat alignment due to pipe loads or thermal expansion. The disc design is most susceptible to leakage. For application under high temperature service, solid wedge is subjected to thermal locking. Thermal locking is a phenomenon in which wedge is stuck between the seats and cause the expansion of the metal. Solid wedge type gate valve are commonly used in moderate to lower pressure temperature application.   

• Flexible wedge: One piece of solid disc with a cut around the perimeter. This cut varies in size, depth and shape. A shallow, narrow cut on wedge perimeter gives strength retains and less flexibility. A cast-in recess or a wider and deeper cut on the wedge perimeter gives more flexibility. This type offers better leak tightness and improves seat alignment. It improves performance in situations such as thermal binding. Thermal binding is a phenomenon in which the wedge is jammed in the close position. The primary causes are a relatively cool valve stem is inserted into a hot valve and the stem warm up and grow further increasing the seating force after closing on torque. As the valve body cool down, the seats contact on the valve wedges locking them in place. Flexible wedges are commonly used in steam system application. The disadvantage of flexible wedge is that line fluid tends to gather in the disc and result in corrosion and ultimately weaken the disc. 

​5. What is rising stem gate valve?

Gate valve designed in rising stem and non-rising stem type. Rising stem gate valve is able to trace open or close position by moving the stem up & down movement and the stem will go up while valve is at opening position. It would move down when the valve is closed. It provides a visual indication of the valve position and making it possible to grease the stem. 
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This valve type is suitable for above ground installation only and the nut rotates around the threaded stem and moves it. The valve is closed when the stem is not visible above the control wheel and the valve is open when the threaded stem extends from top of the wheel. This called OS & Y valve, mean that outside steam and yoke or outside screw and yoke. 
6. What is resilient seated gate valve? 
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Metal seated wedge were widely used before resilient seated gate valve was introduces to the market. The metal seated wedge angular sealing devices and conical wedge valve design requires a depression in valve bottom to ensure the valve is at tight closing position. Some sand and pebbles are embedded in the bore. Regardless of how thoroughly the pipe is flushed upon installation or maintenance, the pipe system installation will not be completely free from impurities Therefore, any metal wedge will eventually lose its ability to be drop-tight and create inefficient installation.

A resilient seated gate valve allows free passage for pebbles and sand in the valve body cause it has a plain or flat valve bottom. The rubber surface will close around the impurities at valve closing position if impurities pass as the valve closed. A high quality rubber element compound absorbs the impurities as the valve closes. When the valve opened again, the impurities will be flushed away. The rubber surface will attain its original shape securing a drop-tight sealing.    ​ ​​7. What is the difference between a gate valve and a ball valve? If system is running in high pressure application, water hammer causes a pipe move and strike against one another. The net pressure of the system isn’t increased significantly and some pipe pressure is far below pipes working pressure capacity, which in turn to safety factor. Serious problems can cause to pipe broken and system damage.  Both ball and gate valve provides similar functions while offering different level of flow control. 

Kindly take note criteria below before you choose the correct valve design: 

1. Application type  
2. Valve flow design 
3. Material 
4. Cost application

​8. Why do gate valves fail?

Gate Valve ANSI

Forged Gate Valve TYPE-AKS

Gate Valve TYPE-AAS

ANSI gate valves are important components in industrial applications and public institutions. Manufactured according to the standards of the American National Standards Institute (ANSI), their established sizes make them easy to install and service. Available in different materials, including steel and stainless steel, ANSI gate valves are an excellent choice when it comes to the reliable shutoff and/or interruption of liquid or gas flows. Choose ANSI gate valves to make sure your system meets the requirements.

Afbv Valve Product Page

How do gate valves work?

Gate valves are operated by means of a hand wheel, an electric motor or a pneumatic or hydraulic device. The valve’s actuation causes the stem to move, which in turn moves the wedge of the gate. This causes the wedge to touch down on the seat and to interrupt the flow through the gate valve. Gate valves can be installed in different horizontal and vertical positions.

If you want to learn more, please visit our website y type globe valve.

Gate valves have a narrow tolerance and a perfect seat, which means that they offer outstanding shutoff performance. To ensure smooth operation and optimum durability, it is important that gate valves be serviced and cleaned on a regular basis.

Another advantage of gate valves is their ability to maintain a consistent flow rate, irrespective of any pressure and temperature changes. The liquid flow in the pipeline can thus be regulated in an efficient and consistent way.

In summary, it can be said that gate valves are an integral part of each and every pipeline as they regulate the liquid flow in a safe and reliable manner. Their cost-efficient design and maintenance as well as their distinguished shutoff performance make them the ideal choice for a wide range of applications.