Dec. 30, 2024
Gate valves are essential components in various process industries, providing efficient control over the flow of fluids and gases. Among the different types of industrial valves, some of the most commonly used variants are covered here. In this article, I have explained different construction, applications, and the advantages they offer.
Afbv Valve contains other products and information you need, so please check it out.
A gate valve can be defined as a type of valve that uses a gate or wedge-type disk, which moves perpendicular to flow to start or stop the fluid flow in piping.
It is the most common type of that used in any process plant. It is a linear motion valve used to start or stop fluid flow. In service, the valve position is either fully open or fully closed gate.
When the gate valve is open fully, the disk is completely removed from the flow. Therefore virtually has no obstruction to flow. Due to this, very little pressure drops across the valve when fluid passes through it.
To achieve proper sealing, 360° surface contact is required between the gate and seats when the valve is fully closed.
It should not be used for regulation or throttling of flow by a partially open gate because accurate control is not possible. The high velocity of the flow in the partially open gate valve may cause erosion of the disc and seating surfaces and also creates vibration and noise.
Unlock New Skills with Our Best Selling Online Courses
Best Selling
How to be an Expert in Piping Valves for Oil & Gas Career
Learn about valves used in Oil & Gas Piping. 18 types of valves, Std & Spec., Manufacturing, Materials, Inspection & Testing.
29.99
20% Discount
Piping Components and Types of Valve Bundle
Learn about Types of Piping Components and Types of Valves in this Course Bundle.
48.99
59.99
Here you can see the main parts of the typical gate valve. The disk of a gate valve is also known as a wedge. Gate valves consist of many parts as listed below. You can learn about each of these parts by visiting this article Valve Trim and Parts Including API Trim Charts
Image- Trouvay & Cauvin
Gate Valves are typically classified into three ways.
Valve Quiz Test yourself, Take This Quiz
A solid wedge is the most common & widely used disk type because of its simplicity and strength. A valve with this type of disk may be installed in any position, and it is suitable for almost all fluids. It can be used in turbulent flow also.
However, it does not compensate for changes in seat alignment due to pipe loads or thermal expansion. So, this type of disk design is most susceptible to leakage. It is subjected to thermal locking if used in high-temperature service.
Thermal locking is a phenomenon in which a valve gate is stuck between the seats due to the expansion of the metal. Solid-wedge gate valves are generally used in moderate to lower pressure-temperature applications.
It is a typical gate valve with no obstruction in the flow path when the valve is fully opened. The gate, fixed to the valve stem, is either threaded into the gate or connected using other mechanisms. When the valve is closed, the gate is lowered to block the flow of fluid, and when opened, it allows the fluid to pass freely through the valve.
Image Velan is a global leader in valve supply. Check their website for more product offerings.
The flexible wedge is a one-piece solid disk with a cut around the perimeter. These cuts vary in size, shape, and depth. A shallow, narrow cut on the wedge perimeter gives less flexibility but retains strength. A cast-in recess or deeper and wider cut on the wedge perimeter gives more flexibility but compromises the strength.
This design improves seat alignment and offers better leak tightness. It also improved performance in situations where thermal binding possible. These types are used in steam systems.
Thermal expansion of the steam line sometime causes distortion of valve bodies which may lead to thermal blinding. The flexible gate allows the gate to flex as the valve seat compresses due to the thermal expansion of the steam pipeline and prevents thermal blinding.
The disadvantage of flexible gates is that line fluid tends to collect in the disk. These may result in corrosion and ultimately weaken the disk.
Unlock New Skills with Our Best Selling Online Courses
Best Selling
How to Read P&ID, PFD and BFD Used in Process Plant
Learn How to Read Piping and Instrument Diagram-P&ID, Process Flow Diagram and Block Flow Diagram used in Process Plant.
29.99
23% Discount
P&ID, Piping Components and Types of Valve Bundle
Learn to Read P&ID drawing, Types of Piping Components and Types of Valves in this Course Bundle.
69.99
89.99
A split wedge Disk consists of two solid pieces and holds together with the help of a special mechanism. You can see the same in the images. In case one-half of the disk is out of alignment, the disk is free to adjust itself to the seating surface. The split disk can be in a wedge shape or a parallel disk type.
Further reading:Are you interested in learning more about Thread Type Gate Valve? Contact us today to secure an expert consultation!
Parallel disks are spring-loaded, so they are always in contact with seats and give bi-directional sealing. The split wedge is suitable for handling noncondensing gasses and liquids at normal and high temperatures.
Freedom of movement of the disk prevents thermal binding even though the valve may have been closed when a line is cold. This means when a line gets heated by fluid and expands, it does not create thermal blinding.
1st is screwed bonnet: This is the simplest design available and it is used for inexpensive valves.
2nd is bolted-bonnet: This is the most popular design and is used in a large number of gate valves. This requires a gasket to seal the joint between the body and the bonnet.
3rd is Welded-Bonnet: This is a popular design where disassembly is not required. They are lighter in weight than their bolted-bonnet counterparts.
4th one is Pressure-Seal Bonnet: This type is used extensively for high-pressure high-temperature applications. The higher the body cavity pressure, the greater the force on the gasket in a pressure-seal valve.
For a rising stem valve, the stem will go up while opening and move down when you close the valve. You can see it in the image. In the inside screw design, the threaded portion of the stem is in contact with the flow medium, and when you open the valve, the handwheel rises with the stem.
Whereas in the case of outside screw design, the only smooth portion is exposed to the flow medium and the stem will rise above the handwheel. This type of valve is also known as OS & Y valve. OS & Y means outside stem and York.
The stem movement will give you a visual indication of valve positions.
Unlock New Skills with Our Best Selling Online Courses
23% Discount
Pumps and Compressors Bundle
Learn Principles, Operation and Design of Centrifugal Pump and Compressor in this Course Bundle.
69.99
89.99
33% Discount
P&ID and Process Control Bundle
Learn about P&ID and Process Control of Process Plants in this Course Bundle.
79.99
119.99
There is no upward movement of the stem in a non-rising stem type. The valve disk is threaded internally. This design slide gate along the stem like a nut when the stem is rotated. You can see the image. This type of valve exposes stem threads to the flow medium when the valve is closed.
Therefore, this design is used where space is limited to allow linear stem movement, and the flow medium does not cause erosion, corrosion, or wear and tear to stem material. This type of valve is also known as an insider screw valve.
A knife gate valve is used in applications where a sharp-edged gate is used to cut through thick fluids, slurries, or powders. This valve is commonly found in the mining, chemical, pulp, and paper industries.
Through-conduit gate valves are designed with gates that are fully enclosed within the valve body. This type of valve is commonly used in applications where a full-bore opening is required to allow the passage of pigging devices.
Image Source www.valbart.com
These valves are versatile devices that find applications in a wide range of industries. The use of a specific type depends on the requirements of the application, the fluid or gas being controlled, and the operating conditions.
Click here to learn about Other Types of Valve
Unlock New Skills with Our Best Selling Online Courses
Best Selling
How to be an Expert in Piping Valves for Oil & Gas Career
Learn about valves used in Oil & Gas Piping. 18 types of valves, Std & Spec., Manufacturing, Materials, Inspection & Testing.
29.99
20% Discount
Piping Components and Types of Valve Bundle
Learn about Types of Piping Components and Types of Valves in this Course Bundle.
48.99
59.99
Gate valves are designed for fully open or fully closed service. They are installed in pipelines as isolating valves and should not be used as control or regulating valves. Operation of a gate valve is performed doing an either clockwise to close (CTC) or clockwise to open (CTO) rotating motion of the stem. When operating the valve stem, the gate moves up- or downwards on the threaded part of the stem.
Gate valves are often used when minimum pressure loss and a free bore is needed. When fully open, a typical gate valve has no obstruction in the flow path resulting in a very low pressure loss, and this design makes it possible to use a pipe-cleaning pig. A gate valve is a multiturn valve meaning that the operation of the valve is done by means of a threaded stem. As the valve has to turn multiple times to go from open to closed position, the slow operation also prevents water hammer effects.
Gate valves can be used for a vast number of fluids. AVK's gate valves are suitable under the following working conditions:
See AVKs installation and maintenance instruction for water/wastewater and gas.
AVK also offers regulating valves. Read more about the benefits.
If you are looking for more details, kindly visit JIS Standard Flange Type Gate Valve.
Previous: Swing Check Valve - Valve engineering
Next: Air Vent versus Air Seperator | Hearth.com Forums Home
If you are interested in sending in a Guest Blogger Submission,welcome to write for us!
All Comments ( 0 )