An Ultimate Gate Valve Guide. Working, Types, and Applications

What are Gate Valves?

Gate valves work exceptionally in many environments. There are many advantages of gate valves due to their efficient structure. People often mistake gate valves vs. Globe valves. The gate valve working is unique and differs from other valves. This ultimate gate valve guide covers everything you need to know about gate valves. The working types and applications of gate valves are described below. Let&#;s check out what is a gate valve.

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What is a Gate Valve?

A gate valve is a plumbing product that controls the fluid flow through pipes. Consider having a pipe that brings water, and you want to control when water flows and stops. In conditions like these, gate valves are the most suitable option.

One of the best gate valve features is their excellent seal-on closure. This property ensures no liquid or gas leaks when the valve gets closed. There are many types of gate valves for water supply and other applications.

Gate valves apply to house water pipes, big pipelines for transport, and power plants. The ideal usage of a gate valve is in regulating gases or liquid flow.

Symbol of Gate Valve:

The symbol of a gate valve contains a vertical line where two triangles meet. The triangles have extended solid lines on the opposite sides at the symbol terminal. In pipelines and instrumentation, the gate valve symbol is modified. As a result, the solid vertical line from the center of the triangles is removed.

Working of Gate Valves:

Gate valve working is like opening and closing a door to control the flow of water or air in a pipe. Consider having you have a giant door inside the pipeline. You can lift it to allow flow or lower to stop it. The gate valve works similarly to this mechanism.  

working principle of gate valves

Open Position: The flow can pass through&#; when&#; the gate valve opens. The &#;door&#; inside the valve, called the gate, lifts, creating an open pathway for water or gas to move through the pipe.

Closed Position: When we want to stop the flow, we close the gate valve. The gate lowers, blocking the pathway inside the valve. Nothing can pass through when the gate is down, and the entire flow stops.

We use a handle to control the gate and move it up or down. Turning the handle lifts or lowers the gate, like a door opening or closing a door. It&#;s like a switch that we can use to control the flow in pipes. In our homes, in big pipelines for oil and gas, or in different industries, they manage the movement of fluids.

Gate Valve Specifications:

Here are the gate valve specifications.

Bronze gate valves from PlumberstarProduct NameBronze Gate Valve MaterialBronzeSize1/2&#;3/4&#;1&#;&#;1-14/&#;&#;1-1/2&#;&#;2&#;&#;2-1/2&#;&#;3&#;&#;4&#;ThreadBSP, NPTTemperature Range-10°C to 120°CPressure200WOGOperationHandwheelBronze Gate Valve specifications

Gate Valve Parts:

Gate valve parts vary for every type and condition being operated in. Yet, some of the parts are mandatory for making up the structure. The body, gate, handle, bonnet, seat, etc., are essential gate valve parts. Let&#;s check out their description.

Gates:

The gate is the most crucial component that decides the gate valve&#;s performance. It comes in a variety of designs and variations to suit specific applications. Parallel and wedge-shaped gates are the most popular ones. Knife, slab, and similar expanding gates are other significant types. Each one of them differs due to their shape and working mechanism.

Gate Valve Body:

The gate valve body acts like a shelter to hold all parts together. It is that point from where the fluid enters and leaves the valves after regulation. Depending on the material used, the valve bodies can be metallic, non-metallic, alloy, or plastic.

It is available in three variants for respective applications. These are cross-flow, reduced, or full-bore designs. The gate valve body also serves connection purposes. The flanges, butts, wafers, or sockets join the valve with the system through the body.

Gate Valve Stem:

The gate valve stem is a central component that controls the disc movement. The rotation of the stem results in the direction of the disc, either lifting or dropping. This stem is directly connected to a handle or actuator to control the operation of the valve. It has a valve disc connection at one end and a handle connection at the other. This way, it maintains control of the functioning of the gate valve.

Gate Valve Bonnet:

Bonnets serve as a protective cover and support to gate valve parts. These parts include the stem, actuators, and disc. They also play a pivotal role in the operation of the branch. Gate valve bonnet material is often identical to that of the body. They connect with the bonnet with the help of bolts, threads, or welding. Some gate valves are bonnetless as their bonnets are merged in the body.

Gate Valve Seat:

The gate valve seat is crucial for the sealing mechanism and positioning of the disc. Most usually, plumbing valves comprise one seat. But gate valves have two seats on the ends of each pipe flange. The correct position of the seat is highly significant for efficient sealing. If it remains unchecked, it can cause gate valve leakages.

Gate Valve Disc:

The gate valve disc is that part that allows escape or blockage of fluid. It moves away from the seat to create a fluid pathway. Similarly, when it moves toward the center, it blocks the path. The mean position or resting point of the disc is the seat.

Yoke and Gland Packing:

Yokes are the arms of the gate valve. They form a connection between the handle and the stem. In some valve designs, they are merged into the bonnets.

Gland packings are secured in the stuffing box to prevent gate valve leakages. A unique structure called sleeves is used to keep it in the box.

Types of Gate Valves:

Here are the gate valve types.

Rising Stem Gate Valve: 

Rising stem gate valve

The stem grows and lowers on turning the handle in rising stem gate valves. When we open the valve, the stem stretches and straightens. At the same time, the branch lies downwards when the valve is closed. This mechanism enables us to understand the valve status by looking at the valve design.

Non-Rising Stem Gate Valve: 

Non-rising stem gate valve

The stem type in this gate valve does not move from its place. Instead, it remains still while the gate inside the valve changes its position from up to down. The best perk of having non-rising stems is their less space consumption. A non-rising stem gate valve is ideal for small places where we cannot install giant valves due to lack of space.

Wedge-Shaped Gate Valve: 

Wedge-shaped gate valve

The gate has a wedge shape in this type. It means the gate wedges between the valve seats when it lowers. They provide a very secure shut-off. They are excellent where a tight seal and resistance to high pressures are necessary.

Bypass Gate Valve:

Bypass gate valve

Bypass gate valves have a unique structure containing an extra passage. This additional duct works like a substitute when we close the gate valve. The fluid can flow and continue its way through a closed valve via this bypass.

The primary purpose of a gate valve with a bypass is to maintain continuous flow. It flows even during maintenance or repair activities on the gate valve itself. Opening the bypass allows fluid to move through the system. At the same time, the gate valve works without interrupting the flow.

Gate Valve Standards:

Here are gate valve standards you should consider before making a selection.

• API B16.34 for Pressure Temperature Rating.
• API 598 for Pressure Testing.
• API 600 for design, material, and testing of steel gate valves.
• ANSI B16.10 for Face to Face.
• NFPA (National Fire Protection Association) for fire protection systems.
• AWWA (American Water Works Association) for wastewater and water applications.

Considering gate valve standards while buying is essential to ensure safety and reliable performance. There could be a few other standards that you could come across at the time of selection. You should consult a credible B2B gate valve manufacturer for custom solutions and plumbing assistance.

Gate Valve Applications:

Here are a few of the most helpful gate valve applications.

Applications of gate valves

Water Supply Systems: 

Gate valves regulate water flow through pipes in water supply systems. There are separate types of gate valves for water supply systems. They have immense switch-like structures that can be on or off at different places, like our homes and schools. When you turn the tap on to wash your hands, a gate valve helps control water flow through the pipes. It is one of the best gate valve applications.

Gas Pipelines: 

Gate valves are crucial in gas pipelines that carry natural gas to homes for cooking and heating. They help regulate gas flow, ensuring the correct amount reaches each place.

Power Plants: 

In power plants, gate valves serve the duty of regulating steam and water flow. Steam generates electricity, and gate valves take steam to the desired locations with excellent carrying ability. Similarly, you can turn off the flow from the gate valve when unnecessary.

Irrigation Systems: 

Gate valves play a role in irrigation systems present in farming. It is among the best gate valve applications. They control the flow of water from within fields during agriculture. They equalize the water supply for the growth of healthy crops.

Oil and Gas Industries: 

Gate valves help in controlling the flow of oil and gas. They enhance safety and bring them to their destination with great care.

Chemical Processing: 

Gate valves in chemical plants control the chemical flow during the manufacturing process.

Water Treatment Plants:

Water treatment plants use gate valves to regulate water flow during purification. They ensure clean and safe water reaches our homes for drinking and other activities.

Sewage Systems: 

Gate valves in sewage systems control wastewater flow and prevent any backflow.

Gate Valve Material Selection:

Gate valve material selection requires consideration of certain factors. It includes pressure and temperature, flow rate, and fluid type. Here are some of the most common gate valve materials and their features.

Stainless Steel: It is suitable for applications like chemicals, petrochemicals, oil and gas. This material can handle corrosive fluids and can operate under high-pressure conditions.
Carbon Steel: It efficiently deals with fluids with moderate pressure, temperature, and non-corrosive media. The applications include steam, gas, and water.
Bronze: It is best for moderate flow rates in seawater and brine. Bronze is resistant to saltwater; thus, it is ideal to operate in such conditions.
Cast Iron: Cast Iron gate valves can handle water, gas, and steam.
Nickel: It is appropriate for high-pressure corrosive media applications. Nickel can function in chemical processing and nuclear power plants.
PVC: PVC can handle low temperatures and pressure media and is non-corrosive. Suitable media for this material are water, alkalis, and acids.
CPVC: CPVC has fluid requirements that are the same as PVC. One distinct difference is that it can control fluid at moderate levels.
Graphite: Ideal to handle chemicals and steam at extremely high temperatures and pressure.

Proper gate valve material selection enhances system performance and reduces maintenance costs. Also, it leads to a long-lasting span of the valve working. The material should also be standard and forged by trusted metal manufacturing companies.

Gate Valve Installation:

Follow these step-by-step instructions for the installation of gate valves.

Materials Needed:

• Gate valve.
• Pipe wrench or adjustable wrench (to tighten the valve).
• Pipe joint compound or Teflon tape (for sealing).

Steps to Install:

Gate valve installation needs careful handling of the product and tools. To start the installation, choose a specific location and cut off the water or gas supply at that point. This step is essential for safety.

Check the gate valve to ensure it fits the size of your pipe. To get the best performance, ensure the valve is free of dirt or debris.

Gate valve installation

Now, put a small amount of pipe joint compound or wrap Teflon tape around the threads on both ends.

The valve should face where you want it to turn to open or close the valve. Screw one end of the valve onto the pipe, turning it clockwise until it&#;s snug. Check if it&#;s straightforward with the help of a level.

Gently turn the gate valve handle for testing to check if it opens and closes smoothly. If the valve works well, you have successfully installed it correctly.

Gate Valve Maintenance Guide:

Here is the gate valve maintenance guide:

• Inspections: Gate valve inspection refers to checking for the signs of damage or leaks. Look for rust, corrosion, or any loose parts over a certain period.
• Lubrication: Lubrication is essential for gate valves to smooth operating parts&#; movement. Use a suitable lubricant for the stem and other moving components. Consider the manufacturer&#;s advice while selecting a lubricant for your product.

• Cleaning: Cleaning is one of the most accessible and primary means to maintain your gate valve. Regular cleaning of surroundings and inner structure ensures optimal performance. It helps remove debris or other particles from disturbing the working of the gate valve.

• Corrosion Prevention: Gate valves exposed to harsh environments or corrosive substances may require additional protection. Consider using coatings or materials designed to resist corrosion in such situations.
• Repair Leaks: Leaks can lead to the wastage of fluids and may occur due to a faulty seal or damaged valve. Repairing leaks can make the gate valve function for a longer time.
• Keep Surrounding Area Clear: Ensure the area around the gate valve is free from obstructions, debris, or any potential hazards that could affect its operation.
• Training and Safety: Only trained personnel handle maintenance tasks for gate valves. Safety is crucial when working with valves, pipes, and pressurized systems.

Gate Valve Buying Guide:

A gate valve buying guide will help you decide when purchasing the suitable gate valve for your needs. Although gate valve price can be a significant factor, there are also a few others. Here are a few factors to remember as a gate valve buying guide.

Valve Size: 

Always opt for a gate valve that syncs with your plumbing system&#;s size or pipe. Gate valves come in various sizes, so select one that fits the diameter of your pipes.

Type of Gate Valve: 

Among various gate valve types, choose the one that suits your application. There are rising stem and non-rising stem gate valves and other classes with many benefits.

Pressure Rating: 

The gate valve&#;s pressure ratings should be equal to your system or higher. It&#;s crucial to avoid installing a valve that cannot handle the stress, as it could lead to failure and leaks.

Temperature Rating: 

Consider the temperature at which the gate valve will operate. Material selection is essential for proper media handling as per specific systems.

Flow Control: 

Determine if your application requires precise flow control or only on-off operation. Gate valves are better suited for on-off control rather than regulating flow.

gate valve and ball valve

FAQs:

Q. Can I use a gate valve for flow regulation?

Gate valves are better for on-off flow control than regulating the flow. Other valves, like globe or butterfly valves, are relatable for precise flow control.

Q. How do I maintain a gate valve?

Gate valve parts need regular maintenance. Their maintenance can be extended to inspections for damage or leaks, lubrication, and operational checks. You also need to perform cleaning, checking seals, etc.

Q. What should I do if there is leakage in my gate valve?

Turn off the water or gas supply immediately if you notice a leak. Check for loose connections or damaged seals. If you can&#;t find the cause, seek assistance from a professional plumber or valve technician.

Q. Can I replace a gate valve myself?

It&#;s essential to have a good understanding of plumbing and gate valve installation. If you have these, you can replace a gate valve yourself.

Q. How long do gate valves last?

The lifespan of a gate valve depends on its quality, materials, usage, and maintenance. Well-maintained gate valves can last many years if you monitor their condition and replace them when necessary.

Conclusion:

This ultimate gate valve guide aims to teach you multiple things about the product. Gate valve working and performance are no doubt very ingenious on their own. They make heavy-duty operations swift and reliable.

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With competitive price and timely delivery, Yaxing Valve sincerely hope to be your supplier and partner.

You must opt for reliable brass gate valve manufacturers before selecting one. Plumberstar is a wholesale plumbing valve and pipe fitting manufacturer. They help you get the best in the market, saving you from the fuss of unnecessary replacements and repairs.

What Is a Knife Gate Valve

Knife gate valves are primarily made for isolation and on-off services in systems with high suspended particle contents. Knife gate valves are particularly useful for managing viscous, corrosive, and abrasive media in addition to the slurry. The valves are easy to use, relatively light in weight, and cost-effective with minimal pressure loss in the completely open position.

Where Are Knife Gate Valves Used

Knife gate valves often have a sharpened blade to cut through thick liquids and are made to function in some of the hardest situations.

They are particularly helpful in applications involving wastewater where corrosion is a significant problem. So, in addition to the valve design optimized for slurry media, it is advantageous to have a knife made of acid-proof stainless steel since it is less susceptible to corrosion damage and so requires less frequent maintenance or even replacement.

Knife gate valves should only be used in situations when a totally open or completely closed state is required; unless specifically intended to do so, they should not be used to control flow. Every time fluid is pushed up against a partially closed gate, a vibration occurs that slowly erodes the disc and seat. The knife gate valves are also made to open and close slowly in order to protect against the effects of the water hammer.

How Do Knife Gate Valves Work

A part called a gate is used by a knife gate valve to operate. The gate&#;s job is to shut and open the passage of fluid. The valve actuator or handwheel, through the stem, provides power to shut and open the gate. The valve actuator or the valve handwheel is attached to the stem. The handwheel is turned counterclockwise to release the valve. The stem also turns in the same direction as the handwheel as it rotates. Threads on the stem are utilized to improve rotational motion. The gate travels upward as the stem spins, creating room for the fluid to pass through the valve as a result of the gate&#;s upward movement. The handwheel must be turned clockwise to shut the valve.

ProsConsLow-pressure dropCan&#;t frequently operationDurableLong switching timeLightweightCan&#;t modulate to fluid capacity or pressureWide range of size Zero leakage Lower costs than other shutoff valves 

Supplier of Stainless Steel and A351 Cf8 304 Pneumatic Knife Pulp Gate Valves

A kind of valve called a stainless steel knife gate valve is driven by a threaded stem and features a knife-like structure within the body that is situated on the pipeline. The Stainless Steel Pulp Valve and other varieties in various sizes, scales, and specifications are produced and supplied by THINKTANK, a renowned manufacturer and supplier. Resilient and metal seated pneumatic knife valves come in a variety of sizes from 2&#; to 54&#;.

What Is the Difference Between Gate Valve vs Knife Gate Valve

Both knife gate valves and wedge-type gate valves are typically intended for on-off services, in which the valve is either fully opened or fully closed. Because fluid pushing against a partially closed gate causes vibration and cavitation, which eventually damages the seat and the body, it is not advised to utilize any of these to control flow. Additionally, in order to lessen the possibility of water hammering, both types of valves are made to open and close slowly.

Both kinds are applicable in situations where: 

• Slurry
• Heavy oil
• Flammable-free viscous liquids
• Seawater
• Wastewater
• Clean water

One of the ways the knife gate valve differs from the gate valve is that it frequently includes a sharpened disc to better cut through the slurry and viscous material. Additionally, compared to a gate valve, which is dimensionally broader, the knife gate valve has a shorter face-to-face length. Because of this, a knife gate valve is lighter than a gate valve. These are the primary variations and most likely two of the knife gate valve&#;s major benefits.

Gate valves are often found in distribution networks, and drinking water pump stations, drinking water mains whereas knife gate valves are typically found in wastewater treatment facilities, chemical industries, mining(coal), chemical industries, as well as many other industrial uses.

Types of Knife Gate Valves

1. Uni-directional Knife Gate Valve

A uni-directional Knife Gate Valve is an on/off uni-directional wafer valve used on an industrial pipeline. When the valve is dealing with particle flow, the unique valve construction avoids the possibility of blocking shutdown. The shear tension generated by the beveled knife gate valve design allows for easier fluid passage.

Wafer Type Knife Gate Valve in a Uni-directional Hopper Shape for Discharge, Material, and Bulk Handling

The wafer type knife gate in a uni-directional hopper shape is made for bulk handling services in the industrial sector (powdered and granular products). The unique body form makes it perfect for use as a silo outflow valve since it facilitates fluid movement. It is often used in sectors like:

• Chemical Plants
• Power Plants
• Mining Plants
• Beverage and Food 

Typically, valves are positioned under silos or hoppers in vertical pipes with the seat on the upstream side to protect it from solids flow. This configuration protects the seat from early corrosion and gate blockage caused by solid buildup.

SizeDN50-DN600Working PressureDN50-DN250(10Bars), DN450(5Bars), DN500-DN600(4Bars)StandardEN PN10, ANSI B16.5 (Class 150)

Lug Type Knife Gate Valve in Uni-directional MSS SP-81 for General Industrial 

The lug type knife gate valve complies with standard MSS-SP-81 and TAPPI-TIS 405 which is a uni-directional design service for pulp paper, mining plants, power plants, the chemical industry, Beverage and food, and wastewater applications.

SizeDN50-DN900Working PressureDN50-DN600(10Bars), DN750(7Bars), DN900(7Bars)StandardEN PN10, ANSI B16.5 (Class 150)

Lug Type Knife Gate Valve in Uni-directional AWWA C520-14 for General Industrial 

The lug type knife gate valve complies with standard AWWA C520-14 for municipal and industrial services. The body and seat&#;s design guarantees a non-clogging cutoff on suspended particles in sectors like:

• Pulp and Paper
• Wastewater
• Food and Beverage
• Chemical Plants
• Power Plants

SizeDN50-DN900Working PressureDN50-DN900(10Bars/150PSI)StandardDIN PN10, ANSI B16.5/B16.47

2. Through Conduit Knife Gate Valve

This valve has significant fugitive emissions. This sort of valve is appropriate for usage in settings where scales help prevent fluid leakage. The design of this type of knife gate valve has two seats and top and bottom gland packing.

Through Conduit Bi-directional Knife Gate Valve Wafer Style for High Density or Concentration Fluids or Media

This knife gate type is a through-conduit wafer valve developed for highly viscous fluids. The double-seat design guarantees a non-clogging shut-off for both forward and backward flow. The valve is utilized in a variety of demanding applications in sectors including:

• Wastewater Treatment Plants
• Pulp & Paper
• Chemical Industry
• Power Plants

SizeDN50-DNWorking PressureDN50-DN125(10Bars), DN150-DN250(8Bars), DN300-DN400(6Bars), DN450(5Bars), DN500-DN600(4Bars), DN700-DN(2Bars)StandardEN PN10, ANSI B16.5

Through Conduit Bidirectional High Performance Knife Gate Valve  Wafer Type for Media or Fluids with a High Consistency or Concentration

This knife gate valve is a bidirectional wafer valve intended for highly viscous liquids. The double-seat construction ensures a non-clogging shut-off for both normal and reverse flow. The valve is used in a variety of applications in sectors such as:

• Wastewater Treatment Plants
• Pulp & Paper
• Chemical Industry
• Power Plants

SizeDN50-DN900Working PressureDN50-DN250(10Bars), DN300-DN900(6Bars, 8Bars with duplex steel gate)StandardDIN PN 6/10/16/25, ANSI B16.5 150LB.

Through Conduit Bidirectional High Pressure Knife Gate Valve Wafer Type for Media or Fluids with a High Consistency or Concentration

Through conduit bidirectional high pressure knife gate valve wafer type designed for media with high consistency. The double seat design assures a non-clogging shut off on either normal or reverse flow. The valve is used for a variety of demanding applications in sectors such as:

• Wastewater Treatment Plants
• Pulp & Paper
• Chemical Plants
• Power Plants

SizeDN300-DNWorking PressureDN300-DN800(10Bars), DN900-DN(6Bars)StandardDIN PN10, EN PN6/16/25, ANSI B16.5.

Uni-directional Round and Square Port Wafer Style Knife Gate Valve for Discharge and Reject Applications

Uni-directional round and square port knife gate is a high-strength valve intended for challenging applications. This valve is appropriate for use in recycle applications, such as waste or dirt mounds of pulpers, high consistency cleaners, or as a solid material silo outlet.

The two-piece body with a circular inlet and a square exit that is bigger than the inlet prevents clogging.

SizeDN100-DN600Working PressureDN100-DN400(7Bars), DN500-DN600(4Bars)StandardEN PN10, ANSI B16.5 Class 150.

3. Bonneted Knife Gate Valve

This kind of knife gate valve has a bonnet and is unidirectional. The body-bonnet construction is totally sealed, thus there is no leakage from the knife gate to the surroundings. For the protection of those around it, this valve is ideal for polluted or hazardous media.

4. Bidirectional Knife Gate Valve

The bidirectional knife gate valve is a bidirectional valve that allows for flow in both directions and has no leakage. The U-shaped form of the peripheral seat assures full-port flow and non-clogging shutdown. It is compatible with a variety of media, including chemicals, pulp stock, sludge, biofuel, slurry, and wastewater.

Knife Gate Valve Parts

NO.Parts NameMaterial 1BodyGGG402Gate  SSSeat Viton/EPDM4PackingPTFE5Gland A216Gr. WCB6Yoke 45#7Stem 2Cr138Stem Nut Brass9Thrust Bearing 65Mn10Bearing Housing A216Gr. WCB11Handwheel GGG30 (Epoxy Coated)12Stem ProtectorSSFastenersA2-70

Bi-directional Knife Gate Valve Wafer Type for General Industrial and Wastewater Treatment Plants

For ordinary industrial service applications, the bi-directional wafer type knife gate valve is a bidirectional valve. The body and seat are designed to prevent clogging in sectors such as:

• Wastewater treatment plants
• Beverage and Food 
• Chemical plants

SizeDN50-DNWorking PressureDN50-DN125(16Bars), DN150-DN250(10Bars), DN300-DN400(6Bars), DN450(6Bars), DN500-DN600(4Bars), DN700-DN(2Bars)StandardEN PN10

MSS SP-81 Bi-directional Knife Gate Valve Lug Type for Pulp and Paper

This knife gate is a bidirectional lug-type valve developed for industrial service applications in accordance with MSS-SP-81 and TAPPI TIS 405-8. The shape of the body and seat ensures non-clogging shutoff of suspended particles in sectors including:

• Pulp and Paper
• Wastewater
• Power Plants
• Mining Coal Application
• Chemical Industry
• Beverage and Food 

SizeDN50-DN900Working PressureDN50-DN600(10Bars/150Psi), DN750(7Bars/100Psi), DN900(7Bars/100Psi)StandardASME B16.5 Class 150

Bi-directional Knife Gate Valve Wafer Type with Stainless Steel Rings for General Industrial 

The stainless steel knife gate valve in bi-directional wafer type is used for pulp and paper, beverage and food, wastewater treatment plants, power plants, and the mining industry. The design of the body and seat ensures the non-clogging shut-off of suspended particles in sectors.

SizeDN50-DN600Working PressureDN50-DN250(10Bars), DN300-DN400(6Bars), DN450(5Bars), DN500-DN600(4Bars)StandardDIN PN 10, ASME B16.5 Class 150

High Pressure Bi-directional Knife Gate Valve Wafer Type for Water Applications and General Industrial

A bi-directional valve called a knife gate is created for use in typical industrial service applications. The body and seat&#;s design guarantees a non-clogging cutoff on suspended particles in sectors like:

• Wastewater treatment plants
• Chemical plants
• Food and Beverage

SizeDN80-DN600Working PressureDN80-DN600(16/20Bars)StandardEN PN16, ASME B16.5 Class 150

5. Slurry Knife Gate Valve

Slurry Bi-directional Knife Gate Valve Wafer Type with Rubber Sleeves

This wafer type knife gate valve is created for a variety of industrial uses. Bi-directional shutoff is provided by the double-seated design. The two rubber sleeves and the valve body&#;s shape make the knife gate valve ideal for use in treating abrasive slurries in sectors like:

• Mining Industry
• Power Industry
• Chemicals
• Wastewater Plants

SizeDN50-DN900Working PressureDN50-DN400(10Bars), DN450-DN600(6/10Bars), DN700-DN900(5Bars)StandardEN PN10, ASME B16.5 Class 150

Slurry Bi-directional Full Flanged Heavy Duty Knife Gate Valve with Rubber Sleeves

This particular form of knife gate valve is a full-flanged, bi-directional valve with two metal-reinforced rubber sleeves for managing abrasive slurries, mostly in the following sectors:

• Mining Industry
• Power Industry
• Chemicals
• Wastewater Treatment Plants

SizeDN80-DN900Working PressureDN80-DN400(10Bars), DN450-DN600(6/10Bars), DN750(5/10Bars), DN900(5/10Bars)StandardDIN PN10, ASME B16.5 Class 150

High Pressure Slurry Knife Gate Valve Full Flanged with Rubber Sleeves Bi-Directional 

This particular form of knife gate is a bi-directional, full-flanged, heavy-duty valve with two metal-reinforced rubber sleeves for handling abrasive slurries, mostly in the following sectors:

• Mining Industry
• Power Industry
• Chemicals
• Wastewater Treatment Plants

SizeDN80-DN900Working PressureDN80-DN900(20Bars, 300Psi)StandardDIN PN10, EN -2, ASME B16.5 Class 300

6. Hopper Shape Knife Gate Valve

This valve features a hopper component at its top. This valve is excellent for bulk media processing. The valve manufacturers design this hopper type knife gate for usage in the chemical industries, food, mining, and others. This valve&#;s seat is positioned in the opposite direction to prevent seat wear, and valve obstruction, and to make it easier to close.

Wafer Type, Unidirectional Hopper-shaped Knife Gate Valve for Material and Bulk Handling Condition

Typically, valves are positioned under silos or hoppers in vertical pipes with the seat on the inlet side to protect it from solids flow. This configuration protects the seat from early deterioration and gate blockage caused by solid buildup. This hopper shape knife gate valve with wafer type is appropriate for use as a silo exit valve due to the body&#;s unique construction, which facilitates the fluid&#;s flow. Numerous industries, including:

• Chemical Plants
• Power Plants
• Beverage and Food 
• Mining Industries

SizeDN50-DN600Working PressureDN50-DN250(10Bars), DN300-DN400(6Bars), DN450(5Bars), DN500-DN600(4Bars)StandardEN PN 10, ASME B16.5 Class 150

7. Square Port Knife Gate Valve

Square Port Knife Gate Valve in Uni-directional for Material, Discharge, and Bulk Handling 

The square port knife gate valve is a low-pressure valve that is primarily utilized in bulk handling and silo outlet applications in several sectors, including:

• Wastewater treatment Plants
• Chemical plants
• Beverage and Food 
• Mining Industries
• Power Plants

SizeSquare DN150x150 to DN600x600Working PressureDN150x150 to DN600x600(1Bar)StandardEN PN 10, ASME B16.5 Class 150

8. Coal Burner Isolation Knife Gate Valve

Bi-directional Knife Gate Valve Wafer Type Used for Coal Burner Isolation

This wafer type knife gate is a bi-directional wafer valve that was created with the particular purpose of isolating the burner lines for pulverized coal in coal-fired boilers during maintenance. The valve is dust-tight, making it appropriate for use in various bulk handling applications like silo outflow valves. This valve conforms with DIN EN and was created for usage in ATEX (areas that might explode) (Explosion resistant equipment). In the case of an explosion, the valve can be employed as an efficient defense against flame spread when it is closed.

SizeDN700-DNWorking PressureDN700-DN(3Bars)StandardDIN PN10

NFPA Full Flange Knife Gate Valve in Uni-directional For Coal Burner Isolation

The uni-directional full-flange type knife gate valve was created specifically to separate the pulverized coal burner lines in coal-fired power plants. These valves were created in accordance with NFPA 85 specifications.

SizeDN200-DN900 (8&#;-36&#;)Working PressureDN700-DN(3.5Bars)StandardDIN PN10, ASME B16.5 Class 150

9. Split Body Knife Gate Valve

Split Body Knife Gate Valve Wafer Uni-directional Type

This knife gate valve is an excellent option for transferring heavy fluids or food, due to its accurate gate guidance inside the body and cast or fabricated construction.

SizeDN50-DN (2&#; to 40&#;)Working PressureDN50-DN125(10Bars), DN150-DN250(8Bars), DN300-DN400(6Bars), DN450(5Bars), DN500-DN600(4Bars), DN700-DN(2Bars)StandardEN PN10, ANSI B16.5ActuatorHandwheel, Pneumatic Actuator, Electric Actuator, or Hydraulic Actuator

Split Body Knife Gate Valve Wafer Bi-Directional Type

Cast construction, bidirectional design, and accurate gate guidance within the body result in a valve suitable for the transport of very heavy fluids, in the food industry.

SizeDN50-DN700 (2&#; to 28&#;)Working PressureDN50-DN700(10Bars)StandardEN PN10, ANSI B16.5ActuatorHandwheel, Pneumatic Actuator, Electric Actuator, or Hydraulic Actuator

10. Transmitter Isolation Knife Gate Valve

Uni-Directional Wafer Type Knife Gate Valve for Transmitter Isolation

This wafer type uni-directional knife gate valve supply isolation of instrument level transmitter can be kept separate from a storage tank. With this valve in place, a transmitter can be replaced or fixed without stopping the process or draining the vessel.

SizeDN80Working PressurePN10StandardEN PN10, ANSI B16.5

11. Double Gate Knife Gate Valve

Bi-directional Knife Double Gate Valve Wafer Type for Media or Fluids with a Very High Consistency or Concentration

The double gate knife valve is frequently used in the pulp and paper industry (recycling or secondary fiber processing) and was created to handle highly concentrated or polluted media. Both gates retract into the body and enable complete flow when they are in the open position. The gates drive stock and impurities like wires and staples into the flow when they close. The stroke time of traditional valves is cut in half. Every wear-and-tear component is replaceable.

SizeDN100-DN600Working PressureDN100-DN250(10Bars), DN300-DN400(6Bars), DN450(5Bars), DN500-DN600(4Bars)StandardEN PN10, ANSI B16.5 Class 150

12. Rising Stem Knife Gate Valve

When the knife gate valve is opened, the stem rises over the handwheel, defining it as such. The stem descends when the valve is closed. The valve operator finds this sort of valve useful since it is simple to determine whether the valve is open or closed. It is advised to use this type of valve in situations where space is not a concern because it takes up a lot of space.

rising stem knife gate valve

13. Non-rising Stem Knife Gate Valve

In this type of knife gate valve, when the valve is opened, the stem does not protrude over the handwheel. This kind of valve has a built-in indicator that lets you know when it is open or closed. This valve may be used in areas with restricted space since it takes up less space than the rising stem type.

non-rising stem knife valve

Pneumatic Knife Gate Valve

With a pressure rating of Class 150, the pneumatic knife gate valve is offered in wafer, lugged, and flanged end connection sizes ranging from 50 mm to 600 mm. Metal seats and resilient seats, both of which can be ordered as unidirectional and bidirectional seats, are available for pneumatic knife gate valves. Electric and hydraulic actuators also can be used to operate the knife gate valve.

THINKTANK provides uni-directional and bi-directional soft and metal seated pneumatic knife gate valves in manual, electric, and pneumatic options. Pneumatic knife gate valves were created specifically for demanding applications. In order to handle the most demanding applications, the Knife gate valve is a one-piece full port cast stainless steel body that is completely lugged. This sturdy design ensures a better flow capacity and little pressure drop.

For a reliable cutoff, pneumatic knife gate valves use gates composed of stainless steel and other premium alloys that are ground with a super surface polish on both sides. The machined and carefully polished gland pockets provide a precise stem seal and leak-proof gland packing. High-Performance knife edge gate valves are offered in uni-directional and bi-directional designs, offering superior performance and value with a number of included features that rival those of competitors.

Pneumatic Knife Gate Valve Accessories:

Gear, pneumatic actuator, electric actuator, or hydraulic actuator all can drive knife edge gate valve for remote operation. Additionally offered are chain wheels and extended stem arrangements. Depending on the customer&#;s requirements, other accessories can be installed with pneumatic cylinder actuators, such as limit switches, solenoid valves, I/P converters, air filter regulators, and even positioners(for throttling flow).

With a shutdown capability that exceeds the specifications of the MSS SP-81 standard, both metal or soft seat options are offered.

Specifications

• Design Standard: MSS SP-81
• Face to Face: As per MSS SP-81
• Testing Standard: MSS SP -81
• Size Range: 50 mm to 600 mm
• Pressure Rating: DN50-DN300(150 psi), DN400-DN450(75 psi), DN500 -DN600(50 psi)
• Ends: Lug Type, Wafer Type, Flangeless, Flange Type

• Valve Operation: Cylinder Pneumatic Actuator, Bevel Gear, Electic Actuator, Chain Wheel, Lever, Handwheel

• Body Design: Round Port / Square Port/V Notch

Materials

a) Body

A wide variety of valve body materials are available for knife gate valves, such as cast iron, carbon steel, stainless steel, duplex steel, and other alloy materials. 

• ASTM A216 GR.WCB
• ASTM A351 GR.CF8
• ASTM A351 GR.CF3
• ASTM A351 GR.CF8M
• ASTM A351 GR.CF3M
• Alloy 20
• Hast Alloy C

b) Knife Gate 

To prevent distortion at high differential pressure and to maintain tight seating, pneumatic knife gate valves use thicker knife gates. Gates that are precisely machined and polished extend the life of seating components and efficiently cut even thick or very viscous fluids. To provide the finest possible seat tightness, the precision finish gate sealing face is lapped and offered in complete materials of construction.

a. Stainless Steel 304
b. Stainless Steel 304L
c. Stainless Steel 316
d. Stainless Steel 316L
e. Alloy 20
f.  Hast Alloy C
g. Nitriding to approx. 600- HV1 surface hardness
h. STL overlay on Gate Edge with min. 1.0mm thickness and min.40 HRC hardness
i. Any Other Special Gate Material

c) Stem :

Generally, the stem of a pneumatic knife gate valve uses stainless steel material to ensure the simple, smooth, long-life operation and trustworthy services. The knife edge gate valve may also be supplied with a stem cover on request for extra dust protection when the valve is open. The knife gate valve is available with extended stem arrangement up to  DN (80&#;) and in rising stem and non-risings stem design, stem m.o.c. is as follows:

a. Stainless Steel 410 (13% Cr.)
b. Stainless Steel 304
c. Stainless Steel 304L
d. Stainless Steel 316
e. Stainless Steel 316L
f.  Alloy 20
g. Hast Alloy C
h. Any Other Special Material on request

d) Gland Packing 

In addition to providing zero leakage from the gland part, the smooth completely machined packing chamber, cast gland follower, multiple packing, and true leveling all contribute to consistent compression of the packing. There are many different types of packing materials to choose from in order to ensure absolute sealing. The numerous types of M.O.C. that may be found in gland packings are as follows:

a. Standard General Service Packing Material
b. P.T.F.E. Impregnated Asbestos, maximum temperature up to 210 C.
c. High Temperature Graphite Asbestos Packing Material
d. Pure PTFE Packing Materials, maximum temperature up to 230 C.
e. Food Grade Packing Material

e) Seat Design

Both integral and renewable types of seats are offered with pneumatic knife edge gate valves. We may provide a replacement seat ring with a hard-facing knife surface for extremely abrasive applications. The service life of the valve is increased by the replaceable seat.

• Integral Metal to Metal Seat
• Renewable Metal to Metal Seat
• Renewable Elastomer Rubber Seat
• Renewable Ptfe Seat
• Deflector Cone.

Testing and Inspection

Body Test

The valve body must undergo a hydrostatic pressure test at 1.5 times the rated operating pressure to comply with standard MSS SP-81.

For example: if the pressure rating is 150psi, then the shell pressure test is 150×1.5=225psi.

Gate Test

The gate must undergo a hydrostatic pressure test to 1.1 times the rated operating pressure in accordance with MSS SP-81.

For example: if the pressure rating is 150psi, then the sealing test is 150×1.1=165psi.

Seat Test

For metal-to-metal seated knife gate valves, the MSS SP-81 specification allows a leakage rate of 40 cc per inch of diameter, per minute at 40 psi pressure. On a 10&#; knife gate valve, this would be equal to 40 times 10, or 400cc per minute at 40psi pressure.

• When tested with water at 40 pressure delivered in the usual flow direction, the maximum permitted leakage is 0.6 GPM.
• When tested with water at 40 psi, there were no obvious leaks (for soft seated valves only).

Face-to-Face Inspection

To ensure simplicity of installation for the customer, independent of the valve manufacturer, MSS SP-81 has set face-to-face dimensions and tolerances for each valve size.

Final Thoughts

In this article, we have known the types of knife gate valves, knife gate valve parts, and application conditions. THINKTANK provides knife gate valves for wastewater treatment plants, chemical plants, seawater treatment plants, power plants, and many other projects in UAE, Germany, Italy, Spain, Singapore, Indonesia, etc. If you have relevant demand, please contact us for a free consultation.

For more information, please visit Knife Gate Valve Manufacturers.