Tag Archive for: resilient seated butterfly valve

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What is the reason for the poor sealing of the valve

Where there is a pipeline, the valve is inseparable. The valve is installed on the pipeline and controls the flow of the fluid medium in the pipeline. It is an important control component. But the valve is also a wearable part. A common valve loss in our life is that the valve is not tightly sealed, resulting in leakage. So what is the reason for the poor

marine valve seat

marine valve seat

sealing of the valve?
The leakage at the packing of the valve is a part of the valve that is prone to leakage failures. The valve is not tightly sealed, and the reasons are probably as follows.
1. Sealing auxiliary structure
Under the change of temperature or sealing force, the structure of the sealing pair will change. And this change will affect and change the force between the sealing pair, so that the performance of the valve sealing is reduced. Therefore, when choosing a seal, be sure to choose a seal with elastic deformation. At the same time, pay attention to the width of the sealing surface. The reason is that the contact surfaces of the sealing pair cannot be completely matched. When the width of the sealing surface increases, the force required for sealing is increased.
2. Specific pressure of sealing surface
The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the specific pressure of the sealing surface is also a very important factor. Under the same conditions, too high specific pressure will cause valve damage, but too low specific pressure will cause valve leakage. Therefore, we need to fully consider the appropriateness of the specific pressure when designing
3. Physical properties of the medium
The physical properties of the medium also affect the valve sealing performance. These physical properties include temperature, viscosity, and hydrophilicity of the surface, among others. The temperature change not only affects the slackness of the sealing pair and the change of the size of the parts, but also has an inseparable relationship with the viscosity of the gas. Gas viscosity increases or decreases with increasing or decreasing temperature. Therefore, in order to reduce the influence of temperature on the sealing performance of the valve, when designing the sealing pair, we should design it as a valve with thermal compensation such as an elastic valve seat. Viscosity is related to the permeability of the fluid. When under the same conditions, the higher the viscosity, the lower the permeability of the fluid. The hydrophilicity of the surface means that when there is a film on the metal surface, the film should be removed. Because of this very thin oil film, it will destroy the hydrophilicity of the surface, resulting in blockage of fluid channels.
4. The quality of the sealing pair
The quality of the sealing pair mainly means that we must check the selection, matching and manufacturing accuracy of materials. For example, the valve disc fits well with the valve seat sealing surface, which can improve the sealing performance. The characteristic of many circumferential waviness is that its labyrinth sealing performance is good.

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

Video of center-lined butterfly valve:

Related news/knowledge:
What are the main factors affecting valve sealing?
Factors Affecting the Operation and Use of resilient seated butterfly valves
Factors affect the sealing performance of butterfly valves
factors affecting the sealing performance of resilient butterfly valve seat

Instructions for the safe use of resilient seated flanged butterfly valves

The resilient seated flanged butterfly valve has the characteristics of small opening torque, flexibility and convenience, labor-saving and energy-saving. The sealing form of the soft seal has reliable performance and can achieve no leakage. Therefore, the use of flange soft-seal butterfly valve is very wide, and it has its presence in all major pipeline systems, and its safe use has gradually attracted attention.

Double flange butterfly valve (16)

Double flange butterfly valve (16)

First of all, the safety of the valve piping system must first consider the main valve. A soft-seal flanged butterfly valve is required to be used as a safety master valve. The function is to cut off and connect the entire pipeline system. In normal production, it is also in the normally open state. The main valve is generally not used to adjust the flow rate and should be installed at the inlet of the main pipeline.
Secondly, a main valve is also needed at the inlet of the branch pipeline. The butterfly valve here is mainly used to control the branch pipeline safely. In addition to the cut-off function, the main valve of the branch pipeline also has the function of adjusting the flow rate. Adjust the flow rate to meet the needs of the branch pipeline flow size, and strictly follow a certain ratio, which is adjusted and controlled by the main valve of each branch pipeline. There should be two flanged soft-seal butterfly valves or safety valves that are often switched on or off or used for adjustment. One of the butterfly valves is spare and is normally open and not in use. A spare valve can be used if there is a problem with the working butterfly valve, so that it will not affect the production. After repairing, a butterfly valve is still reserved as a spare.
On liquid and gas pipelines, a safety drain valve is required at the lowest point or at a suitable place. The function is to empty the medium blocked in the pipeline to avoid air resistance in the pipeline. Because the gas in the pipe will reduce the pipe section, increase the transmission resistance, reduce the flow rate, and affect production. For some special liquids that will dissolve gas after a certain period of time and cannot be discharged during operation, it is also necessary to drain the butterfly valve.
The closing of the resilient seated flanged butterfly valve also has safety requirements. After the valve is closed tightly, some media will also change as the temperature changes, and the thermal expansion of the valve components will increase the pressure between the butterfly valve and the valve seat. When it is turned on again, it will inevitably bring difficulties. Therefore, the torque required to open the valve will be greater than the torque required to close the valve. The resilient seated flanged butterfly valve needs to overcome the increase of static friction due to the increase of the pressure between the sealing surfaces due to the temperature change. Because of the friction between the sealing surfaces, when the valve is closed and opened again, the required torque is much larger than the torque required to close the valve.

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

Video of center-lined butterfly valve: https://youtu.be/NuSZH_AJcwY

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Resilient seated /soft-seal butterfly valve prices

The purchase price of soft-sealed butterfly valves is a problem that many customers are concerned about when inquiring, but because the valve is not like furniture and other items in the structure and material is relatively

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

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

simple, there are more components of the valve, and according to the material used in different working conditions, The components are different, which makes it difficult to give a fixed quotation for the soft-sealed butterfly valve, which should be based on the actual situation. How much it costs to purchase a soft sealing butterfly valve has a lot to do with the material of the valve plate, the material of the valve body, the material of the sealing ring, manual or automatic, etc. Let’s take a look at the specific factors that affect the purchase price of soft-sealed butterfly valves?
1. Material of valve plate. The material of the valve plate of the soft sealing butterfly valve is nylon plate, galvanized plate, 304 plate, 316 plate, etc. The selection of the valve plate is determined according to the medium to be taken by the customer’s pipeline. The general medium mainly relates to whether it is corrosive. If it is not corrosive, you can choose galvanized sheet, and if it is corrosive, you can choose stainless steel 304 plate or 316 plate. Cold-rolled stainless steel costs more than 10,000 yuan per ton, while galvanized steel is several thousand yuan per ton, so obviously the price will be different for different materials.
2. Material of sealing ring. The sealing ring of soft sealing butterfly valve is generally rubber or fluoroplastic. The rubber sealing ring includes nitrile rubber, EPDM rubber, and tetrafluoro rubber. Several rubbers have their own advantages. Nitrile rubber is oil-resistant, and EPDM rubber is resistant to aging. PTFE rubber is resistant to weak corrosion. The temperature resistance of nitrile rubber and EPDM rubber is about 80 degrees, and the temperature resistance of tetrafluoro rubber is about 150 degrees. So we still have to choose according to the temperature and characteristics of the medium. If the temperature is around 80 degrees, you can choose nitrile rubber or EPDM rubber. If the temperature exceeds 80 degrees, you can choose tetrafluoro rubber. Fluoroplastics can also be used when the medium is corrosive but not high temperature. The price of fluoroplastics will be much more economical than rubber.
3. Manual or automatic. The soft sealing butterfly valve is divided into manual and automatic. Manual is the handle butterfly valve, turbine butterfly valve, the driving method is mainly manual. However, electric butterfly valves and pneumatic butterfly valves do not need to be operated manually but are opened and closed automatically by the device. Of course, the price is relatively higher than that of manual ones.
In addition to the above, the size of the valve’s caliber, the size of the applicable pressure, whether it is a flange connection or a wafer connection or an electric welding connection, these factors will all affect the purchase price of the soft sealing butterfly valve. So if you want to know the purchase price of the soft sealing butterfly valve you need, the easiest and best way is to quickly contact our Tanghai staff to give you a professional quotation. According to the working conditions, pressure and medium conditions you provide, Tanghai Professional Services will recommend the most suitable valve types for you and quickly give you an accurate quotation. You are welcome to inquire!

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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Valve stem shaft (TH-VST)

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

What are the characteristics of the soft sealing butterfly valve

Risilient seated /Soft sealing butterfly valve is one of the common butterfly valve types. It is a valve with simple structure and easy operation. It is mainly composed of valve body, valve stem, butterfly plate and sealing ring. The inside of the valve body is a cylindrical shape with a built-in butterfly plate. There are usually two ways to form the seal of a soft-seal butterfly valve. One is that the sealing pair is composed of a non-metallic soft material to a non-metallic soft material. Another is that the sealing pair is composed of a metal hard material to a non-metal soft

wafer type butterfly valve, EPDM seat (10)

wafer type butterfly valve, EPDM seat (10)

material.
The most commonly used materials for the seat ring and seat of soft-sealed butterfly valves are EPDM, nitrile rubber, and polytetrafluoroethylene plastic. The soft-sealed butterfly valve with EPDM rubber seat material usually works in a working environment with a pressure less than 2.5Mpa and a temperature of -50~80℃. Applicable media include salts, acids, metal coating solutions, and water. , Wet chlorine, etc. The soft-sealed butterfly valve with nitrile rubber as the seat material usually works in a working environment with a pressure less than 2.5Mpa and a temperature of -10~90℃. The applicable media include water, oil, waste liquid, etc. The soft-sealed butterfly valve with polytetrafluoroethylene as the seat material can be used in an environment where the pressure is less than or equal to 1.6Mpa and the temperature is -196~200℃. The applicable media include heat resistance, cold resistance, general chemicals and solvents, and most of the liquid.
The advantage of the soft sealing butterfly valve is that it has good sealing performance and can achieve zero leakage. The disadvantage is that it is not resistant to high temperature and high pressure, and the sealing surface is easily eroded by the flowing medium, and the service life is short. The characteristics of the soft sealing butterfly valve are as follows:
1. The valve body is small and light, easy to install, disassemble and repair, and can be installed at any position in the pipeline.
2. The whole valve has a simple structure and is very compact, with small operating torque, and can be opened and closed by rotating 90 degrees.
3. It has good flow regulation performance.
4. The seal can be replaced, the sealing performance is good, and the two-way sealing can be achieved.
5. The butterfly plate can be sprayed with a coating layer, such as nylon rubber or polytetrafluoroethylene, according to the needs of users.
6. Flange connection and wafer connection can be designed according to requirements.
7. According to the requirements of the working conditions, the soft-sealed butterfly valve can be driven manually, electrically or pneumatically.

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

Butterfly valves are classified according to the sealing material, which can be divided into resilient seated   butterfly valves and hard-sealed butterfly valves. There is a big difference in the scope of use between the two. The sealing pair of the resilient seated butterfly valve is composed of two parts. One side of the sealing pair is made of metal hard

U-type-flange-butterfly-valve-2

U-type-flange-butterfly-valve-2

material and the other side is non-metal soft material. This combination makes the resilient seated butterfly valve have good sealing performance and can achieve zero leakage. However, compared with hard-sealed butterfly valves, resilient seated butterfly valves are not suitable for high temperature environments.

The resilient seated butterfly valve is small in size, light in weight, and has good sealing performance. It is responsible for switching on and off and controlling fluid flow in the pipeline system. It has a very wide range of applications in petroleum, chemical, metallurgical, and municipal construction industries.

The connection method of resilient seated butterfly valve is flange type and wafer type. In the process of operating and using resilient seated butterfly valve, some situations are often encountered. Let’s take a look at the factors that affect the operation and use of resilient seated butterfly valve.

  1. In the valve market, rubber and PTFE are the most commonly used sealing materials for resilient seated butterfly valves. These sealing materials can maximize the sealing performance of resilient seatedbutterfly valves, regardless of whether it is a liquid or a gas medium. Zero leakage. However, because of the limitations of the structural characteristics of these sealing materials, the resilient seated  butterfly valve cannot be used in high temperature, high pressure and high-wear circulation pipelines. If any of the above conditions appears in the pipeline, the resilient seated   butterfly valve will malfunction and damage.

    Fluorine lined butterfly valve-PTFE-WAFER (10)

    Fluorine lined butterfly valve-PTFE-WAFER (10)

  2. The sealing ring of the resilient seated butterfly valve is fixed on the valve plate. When the butterfly plate of the butterfly valve is in the open position, the fluid medium in the pipeline will flush the sealing surface of the butterfly valve positively. Under the long-term erosion and corrosion of the fluid medium, the resilient seated material will wear out over time, which will affect the sealing performance of the resilient seated butterfly valve and cause leakage.

The factors that affect the operation of the resilient seated butterfly valve are the above two points. After the operator understands this information, he must pay attention to the use of the resilient seated butterfly valve, master the correct operation method of the resilient seated   butterfly valve, and regularly perform maintenance and repairs to maximize the resilient seated   butterfly valve Play a role and serve our industrial production.

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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resilient seated butterfly valve vs metal seated butterfly valve

Butterfly valve, also called flap valve, has a wide range of uses. It is generally installed on pipelines that transport various corrosive and non-corrosive fluid media in gas, natural gas, liquefied petroleum gas, cold and hot air, chemical smelting and other engineering systems for adjustment. And cut off the flow of the medium. There are many types of butterfly valves, and different types of butterfly valves have different uses. Butterfly valves are classified according to the sealing form and can be divided into soft-sealed /resilient seated butterfly valves and hard-sealed /metal seated butterfly valves. Although there is only one word difference between the two types of butterfly valves, they are very different in terms of structural materials and application fields. This article will analyze the difference between a resilient seated butterfly valve and a metal seated butterfly valve.

wafer type butterfly valve, EPDM seat (10)

wafer type butterfly valve, EPDM seat (10)

The main difference between resilient seated butterfly valve and metal seated butterfly valve lies in the sealing surface:

The two sides of the sealing pair of the resilient seated butterfly valve are made of metal materials on one side, and the other side is made of elastic non-metallic materials, generally rubber or tetrafluoroplastics. The combination of this sealing material makes the resilient seated butterfly valve have good sealing performance, but it is not resistant to high temperature, easy to wear, and has a short service life.

Both sides of the sealing pair of the metal seated butterfly valve are made of metal materials. The metal-to-metal seal makes the sealing performance of the metal seated butterfly valve normal, but it is resistant to high temperature, pressure and abrasion, and has a long service life.

The seat of the soft sealing butterfly valve is made of rubber or tetrafluoroplastic. It has excellent sealing performance and can achieve zero leakage, but it has a relatively short service life and is not resistant to high temperatures. It is also not suitable for some highly corrosive media pipelines. The sealing seat of the hard-sealed butterfly valve is made of metal material, and the sealing performance is

D673H-16C-stainless steel pneumatic triple eccentric butterfly valve

D673H-16C-stainless steel pneumatic triple eccentric butterfly valve

relatively poor, but it is wear-resistant and has strong pressure resistance. It is suitable for strong corrosive medium pipelines.

In addition to the difference in the sealing surface, the difference between the resilient seated butterfly valve and the metal seated butterfly valve is as follows:

  1. Resilient seatedbutterfly valves are mostly center-line type. Metal seatedbutterfly valves are mostly single eccentric, double eccentric and triple eccentric.
  2. The Resilient seatedbutterfly valve is suitable for normal temperature environment. metal seatedbutterfly valves are well adapted to low temperature, normal temperature and high temperature environments.
  3. The Resilient seatedbutterfly valve is suitable for low pressure and normal pressure environment. metal seated butterfly valveis not only suitable for low pressure and normal pressure, but also suitable for medium and high pressure working environment.
  4. As mentioned above, the sealing performance of the Resilient seatedbutterfly valve is better than that of the metal seatedbutterfly valve, but now in order to adapt the hard sealing butterfly valve to more working conditions, it has a special process
  5. The Resilient seatedbutterfly valve is suitable for the two-way opening and closing of the ventilation and dust removal pipeline and the adjustment of water treatment, light industry, petroleum, chemical and other industries. metal seatedbutterfly valves are mostly used in heating, gas, gas, oil, acid and alkali environments.

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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