Lixin - Lixin Valve Group Co., Ltd - Page 13 of 14

What Is a Knife Gate Valve and How Does It Work?

In the realm of industrial flow control, knife gate valves stand out as highly reliable and versatile components. Their unique design and construction make them ideal for a wide range of applications, spanning various industries. Be it the mining, wastewater treatment, or chemical processing industries, knife gate valves deliver unparalleled performance and durability. In this comprehensive guide, we delve into the intricacies of knife gate valves, exploring their mechanism, applications, and the factors to consider when choosing the right valve for your specific needs.

A Knife Gate Valve, a type of valve, used to control the flow of fluids, with a sharp-edged gate to cut through and seal the flow.

Unlocking the Mechanism of Knife Gate Valves

The ingenious design of knife gate valves sets them apart from other valve types. They feature a sliding gate or blade that moves perpendicularly to the flow of the medium. This gate is typically made of a wear-resistant material, such as stainless steel or hardened steel, ensuring longevity and resistance to corrosion. The gate is guided by two parallel seals, forming a tight seal against the valve body to prevent leakage.

The gate's movement is controlled by a stem, which is connected to an actuator. The actuator can be manual, operated by a handwheel or lever, or automated, using electric, pneumatic, or hydraulic power. When the actuator is engaged, it drives the stem, causing the gate to move up or down, thereby controlling the flow of the medium.

 

Unveiling the Applications of Knife Gate Valves

Knife gate valves have earned their place in a diverse spectrum of industries due to their exceptional capabilities. Their inherent design makes them suitable for handling various fluids, including water, wastewater, slurries, and corrosive chemicals. Here are some prominent applications where knife gate valves excel:

1. Mining Industry: Knife gate valves play a crucial role in mining operations, regulating the flow of abrasive slurries and tailings. Their ability to withstand harsh conditions and handle large solids makes them ideal for this demanding environment.

2. Water and Wastewater Treatment: In water treatment facilities, knife gate valves are used to control the flow of water, ensuring efficient distribution and proper treatment. They also find application in wastewater treatment plants, where they help manage the flow of wastewater and prevent contamination.

3. Chemical Processing: Knife gate valves are indispensable in chemical processing plants, where they regulate the flow of corrosive and hazardous fluids. Their robust construction and ability to maintain a tight seal prevent leakage and safeguard against accidents.

4. Power Generation: In power plants, knife gate valves are employed to control the flow of water and steam. Their reliable operation and ability to withstand high temperatures and pressures make them essential components in power generation systems.

5. Food and Beverage Industry: Knife gate valves are widely used in the food and beverage industry, where they ensure hygienic and efficient processing of liquids and semi-solids. Their sanitary design and ease of cleaning make them ideal for this sensitive industry.

 

Navigating the Selection Criteria for Knife Gate Valves

Choosing the right knife gate valve for your application requires careful consideration of several factors:

1. Valve Size: The valve size must align with the required flow rate and pipe diameter. Select a valve with an appropriate size to ensure optimal flow control and minimize pressure drop.

2. Materials of Construction: The materials used for the valve body, gate, and seals should be compatible with the medium being handled. Consider factors such as corrosion resistance, temperature rating, and wear resistance.

3. Pressure Rating: Ensure that the valve's pressure rating exceeds the maximum pressure in your system. This prevents valve failure and ensures safe operation.

4. Temperature Range: Select a valve that can withstand the temperature range of the medium being handled. Consider both normal operating temperatures and potential fluctuations.

5. Actuation Type: Choose the appropriate actuation type based on the desired level of automation and control. Manual actuators are suitable for simple applications, while automated actuators offer remote control and precise operation.

6. Sealing Capabilities: Pay attention to the valve's sealing capabilities to prevent leakage. Different seal materials and designs are available to cater to specific applications and media.

 

Embracing Knife Gate Valve Manufacturers for Reliable Solutions

When procuring knife gate valves, partnering with reputable manufacturers is essential. Lixin Valve Group possesses the expertise, experience, and resources to provide high-quality valves tailored to your specific requirements. We adhere to rigorous quality standards, ensuring the valves meet industry norms and regulations.

Look for knife gate valve manufacturers who offer comprehensive services, including design, engineering, manufacturing, testing, and after-sales service. This ensures a seamless experience from product selection to installation and maintenance.

 

Knife gate valves stand as powerful and adaptable components in industrial flow control systems. Their versatility, durability, and ease of operation make them indispensable across a multitude of applications. By understanding their mechanism, applications, and selection criteria, you can make informed decisions when choosing the right knife gate valve for your specific needs. Partnering with reliable knife gate valve manufacturers guarantees superior quality, exceptional performance, and long-lasting reliability.

Lixin Valve Group Won Again The 2022 Deep Cooperation Award For EPEC Valve Zone Again

Summary Meeting for the 5th Anniversary of the Establishment of EPEC Valve Zone

From March 2 ~ 3th,2023, the summary meeting for the 5th anniversary of the establishment of the EPEC Valve Zone and the 1st annual meeting for procurement and sharing of the valve industry chain were held in Yangzhou. Lixin Valve Group was invited by Nanjing Valve Center to attend the meeting in Yangzhou. And signed the 2023 cooperation agreement for the EPEC valve zone.

Signing ceremony

 

Award Ceremony

At the meeting, medals were awarded to the valve industry chain enterprises that won the 2022 "Deep Cooperation Unit of EPEC". Lixin Valve Group stood out from more than 150 valve industry chain enterprises participating in the meeting and won the "Deep Cooperation Award" of the 2022 EPEC Valve Zone. "Winning the award again is an affirmation and encouragement from Sinopec to Lixin Valve Group. We will work hard and steadily forward, continue to rely on the EPEC Valve Zone, strive to provide better and high-quality products to our customers, and do a good job in various services.".

At the meeting, medals were awarded to the valve industry chain enterprises that won the 2022 "Deep Cooperation Unit of EPEC". Lixin Valve Group stood out from more than 150 valve industry chain enterprises participating in the meeting and won the "Deep Cooperation Award" of the 2022 EPEC Valve Zone. "Winning the award again is an affirmation and encouragement from Sinopec to Lixin Valve Group. We will work hard and steadily forward, continue to rely on the EPEC Valve Zone, strive to provide better and high-quality products to our customers, and do a good job in various services.".

 

The Introduction of DBB Plug Valves

LIXIN DBB Plug Valve is designed, manufactured,tested according to API 6D, it has DBB function of API 6D . Mechanical clamping combined with elastic sealing can achieve strictly sealing. Fully closed disc and seat can form second seal and fire safe. The external safety relief valve relief at 0.2Mpa pressure, prevent abnormal pressure cavity boost.

DBB Plug Valves meet the requirement ofANSI 150 to ANSI 900 (PN20 to PN150) standards. Body can be carbon steel, stainless steel and alloy steel. Size range 2 "to 36" (DN50 to DN900).

DBB Plug Valves have API 6D short series with rectangular hole channel, necking rectangular hole channel and the hole full bore valve

DBB plug suitable for the place need to be more tightly sealed, such as fuel storage and distribution, natural gas, liquefied petroleum gas, oil and other pipeline, used as a cut seal.

Soft rubber seal on the slip of DBB valve wear and tear,the slip can be changed according to nameplate or serial number code.

DBB plug, the following can be referred to as "valve".

Valve rated pressure: The valve pressure - temperature rating shown by Class to determine the appropriate  rating  level  pressure  according  to  ASME  B16.34  Material  Group  table.  The  valve pressure - temperature rating shown by PN determine the appropriate rating level pressure. according to EN 1092-1 table.

About Leakage of Metal Seat For Knife Gate Valve

Our metal seated Knife Gate Valve is made as per the specification of MSS SP-81.As we see, the article 10.2 of this standard specified the leakage rate of this valve,that means the valve’s seal leakage is allowable.

Through all the international manufacture designs of metal seated knife gate valve,disc seal need very big pressure ratio,but actually the seal can only offer little pressure ratio because the structure design,it too hard to fulfill,so caused seal leakage.

If the medium is dry ash,paper slurry,particle calcium carbide etc. self-seal flow.From the view of physics,the water molecules’ diameter is far smaller than dry ash and other composition of the flow.It’s more easier to across the micro tunnel of seal face,cause leakage.But the self-seal medium will jam the micro leakage tunnel automaticly under the pressure when the valve is closed,and this can reach the leakage rate of the national standard,and fulfill clients’ application.

So,we do not do seal tests,and shell hydraulic test only.

PTFE Packing Leakage Reason

Before delivery LIIXN made test for all the valves,and why it also have leakage?

We presume that:

1. When the valve is make pressure test, there will be force to cause the packing to expand, and after the test, the external force is lost, which may cause the bolt to be a little loose

2. The valve needs to be ultrasonically cleaned before leaving the factory, so that the dirt and oil on the surface of the valve can be removed, but when it is cleaned by ultrasonically, it will vibrate and cause the bolts to become loose.

Lift Type Plug Valve Working Process

Process of opening and closing of the valve. When open the valve, firstly turn the handwheel to make the plug lifted and separated with the sealed surface, then turn the handle by 90 degree to connect the channel of plug with the channel of valve body. So that the valve is opened. When close the valve, firstly turn the handle by 90 degree to make the channel of plug vertical to the channel of the valve body, then the handwheel to descend the plug, so that the valve is closed.

Oil Resistant Sealing Grease Daston 7903

Daston 7903 is a high-performance sealing and lubricating compound, formulated from synthetic fluids and thickened with an advanced organic clay thickener. It is designed to meet the demanding requirements of a variety of industrial applications.

Key Features & Benefits

  • Superior Adhesion & Sealing Performance: Provides reliable bonding and sealing in various conditions.

  • Enhanced Resistance: Offers excellent pressure resistance, vibration resistance, and is insoluble, non-separating, and non-solidifying, ensuring long-lasting performance.

  • Chemical & Fluid Resistance: Highly resistant to gasoline, kerosene, lubricants, water, LPG, and other harsh chemicals.

  • Thermal & Chemical Stability: Maintains stability under extreme temperatures and exposure to chemicals, enhancing durability.

Applications

  • Static Sealing: Ideal for sealing equipment, piping, and valves in contact with fuels like gasoline, kerosene, lubricants, water, and LPG.

  • Sealing & Lubrication: Suitable for sealing surfaces that experience slow sliding and rotation, including oil and gas pipelines, valves, and similar systems.

Why Choose Daston 7903?

Daston 7903 is especially engineered to handle the high demands of the oil and gas industry, making it perfect for ensuring reliable lubrication and sealing in critical applications like pipelines and valves. It’s the trusted choice for industries that require enhanced performance in harsh environments.

For the Lubricated type Plug valve, the sealing grease should be injected into the sealing part. (Note)

Note: For more than two times of switching (excluding the second time), sealing grease must be added to make up for the natural leakage of sealing grease due to over-frequency switching, so as to ensure the dosage of sealing grease in the valve body. If you need to repeat the switch pressure test several times, follow the above requirements and so on.

Selection Method

The customer should provide the valve type, size, pressure, temperature, and description, etc.

In the case that the customer does not provide the structural length, our company installs API 6D as the standard

In the case that the customer does not provide the flange standard, our company installs it with ANSI B 16.5a as the standard

Please provide standard number and detailed information

Use of The Product

1 The operating pressure shall not exceed the pressure in the product performance specification table and the operating temperature of the product.

2 When the valve is installed horizontally, the valve should be supported accordingly, especially to prevent the large-diameter valve driver from damaging the valve due to gravity.

3 When cleaning the pipeline, the valve should be in a fully open state.

4 Valves with cleaning pipes should be cleaned regularly (preferably once a week), and the specific cycle depends on the specific working conditions;

5 Take measures to prevent long-term violent vibration of the valve on the pipeline to avoid fatigue failure and leakage of the valve.

6 The valve must not replace the packing under pressure, and the upper sealing structure is not a reason for the user to replace the packing under pressure.

7 The design of this valve has not carried out life calculation, test and fatigue strength check, and the user must regularly check and replace it during use.

8 The design of this valve does not consider the seismic load, and the manufacturer is not responsible for the consequences caused by this.

9 The valve must be protected when installed in the open air.

10 During the use of the valve, the stem, stem nut and bearing should be lubricated once a week to ensure that the valve can be opened and closed flexibly.

Valve Installation

1 The detailed valve and pipe flange installation method are as follows

2 The position of the valve installation pipe is as shown in the figure below (the valve can be installed in various positions, but we recommend using it in the most suitable position):

3 The valve can only be installed in one direction. The direction of the sealing ring is consistent with the flow direction of the medium. The user must confirm the flow direction of the medium and install the valve in the direction of the arrow on the valve body.

4 After the flanged valve is welded and installed on the pipe flange, do not install the valve immediately. The pipe work can only be carried out after normal temperature. It is absolutely forbidden to weld the pipe after the valve is installed on the flange;

5 When installing the valve, you should consider the convenience of operation, and install the valve in an easy-to-operate place as much as possible;

6 Tighten the bolts on the flange according to the above installation method. The pipe bolts should be tightened diagonally. Be careful not to tighten unilaterally. Unilateral tightening may cause leakage;

Note! It is advisable to use proper force when screwing the fastener bolts to achieve a complete seal between the flange and the valve.

Maintenance & Installation & Solution

1 The valve is forbidden to be transported by hanging on the handwheel with a hook

2 Before the valve is used, both ends of the flow channel must be plugged with valve sleeves to prevent dust impurities from entering, and there must be plug sleeves to protect the sealing surface. Keep the valve dry and ventilated. When the valve is not used for a long time, the inner cavity of the valve should be cleaned. Clean, additionally coated with anti-rust oil to prevent rust.

3 Before the valve is installed, it is necessary to check whether there is any impurities in the valve cavity, and check whether the valve is open or closed.

4 The valve must be installed in the pipeline in a horizontal state, and must not be suspended, inclined, etc., and a bracket must be provided in the suspended position.

5 Each time the valve is opened and closed, the valve position indicator must be in the same position as described above.

6 When the valve needs maintenance in the pipeline, the valve should be in a half-open and half-closed state, and then withdraw for maintenance

7 During the use of the valve, check the tightness of the bolts and nuts, and stop when necessary.

 

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