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factors affecting the sealing performance of resilient butterfly valve seat

Rubber butterfly valve is an important part of regulating flow medium, and tight sealing is the most important quality of the product. The sealing performance of rubber butterfly valves is affected by many factors, and the most important influence is still closely related to the sealing surface. Today we will focus on three factors. Let’s take a

Wafer type butterfly valve with worm gear

Wafer type butterfly valve with worm gear

look at the main factors that affect the sealing performance of rubber butterfly valves:

1. Quality of the sealing surface/valve seat
First of all, we must make it clear that the sealing surface refers to the part where the valve seat and the disc are in contact with each other for medium opening and closing control, and only which part of the valve seat and the disc are in contact instead of the entire sealing pair. The quality of the sealing surface is mainly related to the quality of the sealing material. The quality of the sealing material should be produced by the brand manufacturer and qualified in process. In addition, the choice of sealing material should be in line with the medium. For example, rubber butterfly valves cannot be used for highly corrosive media.

2. Width of sealing surface/valve seat
The width of the sealing surface mainly affects the movement resistance of the fluid. The larger the sealing surface, the lower the resistance, and the narrower the resistance is relatively large. Therefore, the increase in the width of the sealing surface can reduce the erosion and wear of the sealing surface by the fluid. At the same time, because the increase in the width of the sealing surface increases the length of the leakage stroke proportionally, the leakage can be reduced proportionally. However, the width of the sealing surface must not be excessively increased, because an increase in the width of the sealing surface, under the same sealing force, the reduction of the specific pressure of the seal will increase the possibility of leakage.

3. The pressure difference between before and after the valve
The specific pressure on the sealing surface is caused by the pressure difference between the front and rear of the valve and the applied sealing force, which refers to the pressure acting on a unit area of ​​the sealing surface. The specific pressure directly affects the sealing performance, reliability and service life of the rubber butterfly valve. When the specific pressure on the sealing surface is small and the surface roughness is low, the leakage increases rapidly. When the specific pressure on the sealing surface is large, the effect of surface roughness on the leakage is significantly reduced.

In addition, the sealing performance of the rubber butterfly valve is related to the sealing surface material of the butterfly valve and its processing state, the nature of the medium, the existence of the sealing oil film, the rigidity and structural characteristics of the closing part, and so on. For more information, please call Tanghai for inquiries, and we will have professionals to answer your questions about butterfly valves.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Factors Affecting the Operation and Use of resilient seated Butterfly Valves
What are the main factors affecting valve sealing?
Installation requirements for manual butterfly valves

Introduction to the Features of Lever Wafer Butterfly Valve

Lever or Handle wafer butterfly valve is a kind of butterfly valve, usually with soft seal, which consists of a sealing surface made of rubber or fluoroplastic as a sealing material and a valve plate and stem made of carbon steel or

wafer-type-butterfly-valve-with-handle-13

wafer-type-butterfly-valve-with-handle-13

stainless steel. Due to the limitation of the sealing surface material, the handle wafer butterfly valve is only suitable for water, gas, oil and other fluid media with a temperature of ≤80~120℃. The application fields include chemical industry, petroleum, electric power, textile, papermaking, construction water supply and drainage, etc. It is used for on-off control of normal temperature and pressure pipeline media on pipelines that transport various corrosive and non-corrosive fluid media in the engineering system, and can also be used for flow adjustment.
Handle wafer butterfly valves are generally only suitable for small-diameter valves, that is, valves with a diameter less than or equal to DN200mm. Because the small-diameter torque is relatively small, the opening and closing of the valve can be directly controlled by hand. The caliber is greater than 200mm, and according to the specific size of the caliber, it needs to be equipped with a turbine head, a pneumatic device or an electric device.
Because the handle wafer butterfly valve is a soft sealing butterfly valve, when the valve is installed and used, the valve must be opened at an angle, which is generally between 5°-10°. Do not allow the sealing surface rubber to be squeezed for a long time. state.
The main features of the handle wafer butterfly valve are:
1. The design structure is simple and unique, small in size, light in weight, and easy to operate.
2. Small-caliber operating torque is small, labor-saving and dexterous, opening and closing quickly.
3. It can be installed at any position of the pipeline, which is very convenient for installation and maintenance.
4. Handle wafer butterfly valves are usually soft-sealed, with reliable sealing performance, and can achieve two-way sealing with zero leakage.
5. The sealing surface material is easy to replace, resistant to aging, weak corrosion, and has a long service life.
Founded in 1994, Tanghai Valve is a professional valve manufacturer integrating design, development, production, sales, installation and service, and a high-quality valve manufacturer. The leading products include: wafer butterfly valves, flanged butterfly valves, hard-sealed butterfly valves, gate valves, butterfly check valves and other water series control valve products and related supporting pipeline accessories. The product sales range covers all parts of the country, and it has developed steadily in developing countries and regions such as Asia, Africa, and Latin America, and has successfully opened markets in developed countries and regions such as Europe and the United States. Products are widely used in water supply and drainage, electric power, petrochemical, metallurgical and other industries.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Design Features of Electric Gate Valve

An electric gate valve is a gate valve that uses an electric actuator to control the opening and closing of the valve. Its structure can be divided into upper and lower parts, the upper part is the electric actuator, and the lower part is the gate valve body. Connect the electric actuator and the gate valve, after installation and debugging, it becomes an electric gate valve. The electric gate valve uses electric energy to realize the opening and closing of the valve, so as to control the interception and circulation of the pipeline medium.

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

The switching speed of the electric gate valve can be adjusted, the structure is relatively simple, and the maintenance is easier. Its design structure also has its own characteristics.
1. The electric gate valve adopts pressure self-tightening seal, which has excellent sealing performance and is reliable and safe to use.
2. The electric gate valve adopts a double gate with a universal roof structure in the middle, which can automatically adjust the degree of sealing between the gate and the valve seat to ensure the sealing performance of the valve. At the same time, this structure is very convenient to maintain and save costs.
3. The sealing surface of the gate and the valve seat is made of cobalt-chromium-tungsten cemented carbide by plasma spray welding. The sealing surface has high hardness, and is very wear-resistant and corrosion-resistant, which prolongs the service life of the valve.
4. The valve stem is made of nitrided steel, and the surface is nitrided, which has high hardness, good performance and long life.
5. The electric device of the electric gate valve is equipped with a torque control mechanism, an on-site operating mechanism and a hand and electric switching mechanism. It can also carry out remote operation and intelligent control. It is suitable for use in situations where manual operation is difficult or the pipeline environment is complex and dangerous.
6. When the electric gate valve is used for the first time, during installation and debugging, it is necessary to manually open the valve to about half of the position, so as to avoid the valve or electrical equipment damage due to the reverse connection of the motor phase sequence.

TH Valve is a professional manufacturer of butterfly valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Working principle of electric gate valve
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Types and selection of electric valves

Structural characteristics of butterfly valve

The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the valve body of the butterfly valve, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When it is rotated to 90°, the valve is fully opened.

The butterfly valve has a simple structure, small volume and light weight, and is composed of only a few parts. And only need to rotate 90 ° to quickly open and

U-type-flange-butterfly-valve-2

U-type-flange-butterfly-valve-2

close, simple operation, and the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the single resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. There are two types of butterfly valve: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.

Valves with metal seals generally have a longer life-time than valves with elastic seals, but it is difficult to achieve complete sealing. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being limited by temperature.

If the butterfly valve is required to be used as a flow control, the main thing is to choose the valve size and type correctly. The structure principle of the butterfly valve is especially suitable for making large-diameter valves. Butterfly valves are not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also in cooling water systems of thermal power stations.

Commonly used butterfly valves are wafer-type butterfly valves and flanged butterfly valves. Wafer type butterfly valve is to connect the valve between the two pipeline flanges with double-headed bolts. Flange type butterfly valve is to have a flange on the valve, and use bolts to connect the two ends of the valve to the pipeline flange. There are four types of butterfly valves in Tanghai Valve company, see below:

Butterfly Valve

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China. It was founded in 2006. Its predecessor was Tanghai Valve Manufacturing Factory. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services.

Related news: The structural characteristics and uses of the wafer butterfly valve; What is a wafer type butterfly valve;