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Difference between Soft seal gate valve and hard seal gate valve

July 28, 2020

Soft seal gate valve and hard seal gate valve are two major categories in the gate valve series. Hard seal and soft seal can sometimes compensate for each other, and

13 gate-valve-5

sometimes they are independent of each other. So what is the relationship between soft seal gate valve and hard seal gate valve? What are the main differences? Next, the editor of Tanghai Valve will solve these mysteries for everyone.

1. Sealing material

Soft seal gate valve: the seal pair is made of metal materials on one side and elastic non-metallic materials on the other side, which is called “soft seal”. This kind of seal has good sealing performance, but it is not resistant to high temperature, easy to wear, and has poor mechanical properties.

Hard seal gate valve: The two sides of the seal pair are made of metal materials or other harder materials are called “hard seals”. This kind of seal has poor sealing performance, but has high temperature resistance, abrasion resistance and good mechanical properties.

2. Structure mechanism

The hard seal gate valve is a seal between metal and metal, and the sealing ball and valve seat are both metal. Machining accuracy and craftsmanship are more difficult, and are generally used in high pressure, usually above 35MPa. The soft seal gate valve is a seal between metal and non-metal, such as nylon\tetrafluoroethylene, and the manufacturing standards are the same.

3. Equipment selection

The selection of soft and hard seal gate valves is mainly based on the process medium, temperature and pressure. Generally, the medium contains solid particles or wears or the temperature is higher than 200 degrees. It is best to use hard seals. Valves with a diameter greater than 50 have a larger pressure difference and consider opening the valve torque. , When the torque is large, the fixed hard-seal ball valve should be selected, and its sealing level can reach 6 regardless of the soft or hard seal.

3. Conditions of use

The soft seal gate valve generally has a very high seal, while the hard seal can be high or low according to the requirements; the soft seal needs to be fireproof, because the material of the soft seal will leak at high temperatures, while the hard seal does not have this problem; Seals can generally be made at very high pressures, but soft seals cannot; soft seals cannot be used in some situations due to the problem of the flowing medium. Finally, hard seal valves are generally more expensive than soft seals. As for manufacturing, there is little difference between the two, mainly the difference between the valve seat, the soft seal is non-metallic, and the hard seal is metallic.

Through the above introduction, I believe everyone can understand the difference between soft seal gate valve and hard seal gate valve. With the continuous development of China’s industrial market, it is necessary to understand the difference between soft seal gate valve and hard seal gate valve, which may not only affect Production efficiency may also greatly affect economic efficiency

Difference between soft seal butterfly valve and hard seal butterfly valve

July 28, 2020

The difference between soft seal butterfly valve and hard seal butterfly valve:

A butterfly valve hard seal refers to a “hard seal” in which both sides of the seal pair are made of metal materials or other harder materials. This kind of seal has poor

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

sealing performance, but high temperature resistance, wear resistance, and good mechanical properties. For example, : Steel + Steel; Steel + Copper; Steel + Graphite; Steel + Alloy Steel; (The steel here may also be cast iron, cast steel, alloy steel or surfacing, sprayed alloy).

The soft seal seal pair is made of metal materials on one side and elastic non-metallic materials on the other side. It is called “soft seal”. This kind of seal has better sealing performance, but it is not resistant to high temperatures, easy to wear, and mechanical Poor performance. Such as: steel + rubber; steel + tetrafluoropolyethylene; etc. The soft sealing seat is made of non-metallic materials with certain strength, hardness and temperature resistance, with good sealing performance, zero leakage, but life And the adaptability to temperature is relatively poor. The hard seal is made of metal, and the sealing performance is relatively poor, although some manufacturers claim that it can achieve zero leakage. The soft seal cannot meet the process requirements for some corrosive materials, and the hard seal can solve it! These two types of seals can complement each other. In terms of tightness, the soft seal is relatively good, but now the tightness of the hard seal can also meet the corresponding requirements! The advantage of the soft seal is good sealing performance, but the disadvantage is that it is easy to age, wear, and has a short service life. The hard seal has a long service life, but the tightness is relatively worse than that of the soft seal.

The main differences in its structure are as follows
1. The difference in structure

Soft seal butterfly valves are mostly centerline type, and hard seals are mostly single eccentric, double eccentric, and triple eccentric butterfly valves.

2. Temperature resistance

The soft seal is used in normal temperature environment. Hard seal can be used in low temperature, normal temperature, high temperature and other environments

3. Pressure

Soft seal low pressure-normal pressure, hard seal can also be used in medium and high pressure conditions

4. Sealing performance: The soft sealing and triple eccentric hard sealing butterfly valves have better sealing performance. The triple eccentric butterfly valve can maintain good sealing under high pressure and high temperature environment.

In view of the above characteristics, the soft sealing butterfly valve is suitable for the two-way opening and closing and adjustment of ventilation and dust removal pipelines, water treatment, light industry, petroleum, chemical and other industries. Hard-sealed butterfly valves are mostly used in heating, gas, gas, oil, acid and alkali environments.

With the widespread use of butterfly valves, its features of convenient installation, convenient maintenance and simple structure become more and more obvious. Electric soft-sealed butterfly valves, pneumatic soft-sealed butterfly valves, hard-sealed butterfly valves, etc. have begun to replace electric gate valves and globe valves in more and more occasions.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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

Triple eccentric multi-level hard sealing flange butterfly valve

July 27, 2020

The triple eccentric multi-level hard-sealed flange butterfly valve is a valve designed with the principle of three-dimensional knitting. The product is composed of

triple eccentric butterfly valve-wafer-butt weld (1)

main components such as valve body, butterfly plate, multi-level valve seat, valve stem, and transmission mechanism. It is widely used in the pipelines of corrosive media such as metallurgy, electric power, petroleum, chemical industry, air, gas, combustible gas and water supply and drainage.

Overview of Triple eccentric multi-level hard sealing flange butterfly valve:
Triple eccentric multi-level hard-sealed flange butterfly valve is a long-life, energy-saving butterfly valve. Its structure adopts three-dimensional core design principle, the valve seat adopts a multi-layer structure compatible with hard and soft sealing, exquisite processing and advanced technology. This product is composed of main components such as valve body, butterfly plate, multi-level valve seat, valve stem and transmission mechanism. It is widely used in the pipelines of corrosive media such as metallurgy, electric power, petroleum, chemical industry, air, gas, combustible gas and water supply and drainage.

Use of Triple eccentric multi-level hard sealing flange butterfly valve:
The triple-eccentric multi-layered hard-sealed flange butterfly valve has the characteristics of simple structure, small size, light weight, low material consumption, small installation size, rapid switching, 90° reciprocating rotation, and small driving torque. It is used to cut off, connect, and adjust tubes. The medium in the road has good fluid control characteristics and close sealing performance. It is widely used in the pipelines of corrosive media such as metallurgy, electric power, petroleum, chemical industry, air, gas, combustible gas and water supply and drainage.

Features of Triple eccentric multi-level hard sealing flange butterfly valve:

The triple eccentric multi-level hard sealing flange butterfly valve adopts the three-dimensional eccentric principle design, so that the space movement trajectory of the sealing surface is idealized. There is no friction and interference between the sealing surfaces, and the sealing material is selected properly, so that the butterfly valve can be sealed. Performance, corrosion resistance, high temperature resistance and wear resistance have been reliably guaranteed. Its main features are as follows:

1. The opening torque is small, flexible and convenient, labor-saving and energy-saving.

2. The three-dimensional knitting core structure makes the butterfly plate tighter and tighter, and its sealing performance is reliable and leak-free.

3. High pressure resistance, corrosion resistance, wear resistance, long service life, etc.

Adopt standards:

Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, GB and other international standards.

The main technical parameters
Nominal diameter DN (mm) 50～2000
Nominal pressure PN (MPa) 0.6 1.0 1.6 2.5 4.0
Test pressure Strength test 0.9 1.5 2.4 3.75 6.0
Seal test 0.66 1.1 1.76 2.75 4.4
Hermetic sealing test 0.6 0.6 0.6 0.6 0.6
Leakage rate <0.1×DNmm/s (in line with GB/T13927-92 standard)
Applicable temperature Carbon steel: -29℃～425℃ Stainless steel -40℃～600℃
Applicable medium: air, water, steam, gas, oil, acid, alkali, salt with weak corrosive medium, etc.
Drive form: Worm gear drive, pneumatic drive, electric drive

Installation instructions of double eccentric butterfly valve

July 24, 2020

Installation instructions of double eccentric butterfly valve:
1. Before installation, you must carefully check whether the valve’s mark and certificate of conformity meet the requirements for use, and clean it after verification.

Double eccentric-wafer butterfly valve-D72F-150lbP-stainless steel (3)

Uninstalled valves should be stored in a dry room. Valves stored for a long time should be cleaned regularly, dried and coated with anti-rust oil. Blind plates shall be used to protect the flange sealing surface at both ends of the valve.
2. Install according to the flow direction of the medium; horizontal installation is preferred.
3. The connecting bolts of the butterfly valve and the pipeline should be tightened several times in the diagonal direction during installation, and no single piece should be tightened at a time to prevent the flange connection from leaking due to uneven force.
4. When installing the butterfly valve, the butterfly plate should be in the closed position to prevent debris from entering the valve cavity and scratching the sealing surface. When the user wants to test the pressure, be sure to install the flange pair on both ends and test the pressure.
5. When connecting the valve to the pipeline, it is required to use butt-welded steel flanges or special butterfly valve flanges on the pipeline. If flat-welded steel flanges are used, the inner hole of the flange must be the same size as the inner hole of the gasket to ensure the effective sealing surface of the gasket.
6. When the electric butterfly valve leaves the factory, the opening and closing stroke of the control mechanism has been adjusted. In order to prevent the direction from being wrong when the power is turned on, the user must manually move to 1/3 of the closed position before turning on the power for the first time. And check whether the direction of the indicator plate is consistent with the opening direction of the valve.
7. When the valve is in use, if any malfunction is found, stop using it immediately

Tanghai Valve is the best manufacturer of double eccentric butterfly valve in China. We produce the best quality products with competitive low prices. Main products: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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

Classification and features of Eccentric butterfly valves

July 24, 2020

Eccentric butterfly valves are divided into single eccentric butterfly valves, double eccentric butterfly valves, triple eccentric butterfly valves, and variable eccentric butterfly valves. Contrast with concentric butterfly valve. A butterfly valve whose stem axis deviates from the center of the disc and the center of the body at the same time, and the sealing pair is an oblique vertebra is called an eccentric butterfly valve.

high performance-double eccentric-butterlfy valve-wafer-lug-flanged (5)

Structure classification of eccentric butterfly valve:
Single eccentric butterfly valve
In order to solve the problem of the extrusion of the butterfly plate and the valve seat of the concentric butterfly valve, a single eccentric butterfly valve was produced. Its structural feature is that the shaft center of the valve stem deviates from the center of the butterfly plate, so that the lower end of the butterfly plate no longer becomes the rotation axis. Disperse and reduce the excessive squeezing between the lower end of the butterfly plate and the valve seat.
Double eccentric butterfly valve
On the basis of the single eccentric butterfly valve, the double eccentric butterfly valve is the most widely used double eccentric butterfly valve. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved.
Triple eccentric butterfly valve
To withstand high temperatures, hard seals must be used, but the amount of leakage is large; for zero leakage, soft seals must be used, but they are not resistant to high temperatures. In order to overcome the contradiction of the double eccentric butterfly valve, the butterfly valve was eccentric for the third time. The so-called third eccentricity means that the shape of the sealing pair is not a positive cone, but an oblique cone.
Variable eccentric butterfly valve
The uniqueness of the variable eccentric butterfly valve is that the valve stem shaft where the butterfly plate is installed is a three-segment shaft structure. The three-segment shaft type valve stem has two shaft sections concentric, and the center line of the central shaft is offset from the two ends of the axis by a center distance , The butterfly plate is installed on the intermediate shaft section. Such an eccentric structure makes the butterfly plate a double eccentric shape when in the fully open position, and a single eccentric shape when the butterfly plate rotates to the closed position. Due to the effect of the eccentric shaft, when close to closing, the butterfly plate moves a

triple eccentric butterfly valve-lug

distance into the sealing cone surface of the valve seat, and the butterfly plate matches the sealing surface of the valve seat to achieve reliable sealing performance.

Features of eccentric butterfly valve:

The butterfly valve and the upper and lower valve shafts are connected by special-shaped holes and special-shaped shafts. During the opening and closing process of the butterfly plate, the function of the butterfly plate floating up and down, left and right, without a pin link, reduces the interference area between the butterfly plate and the valve seat. Thereby greatly reducing the torque. The floating structure of the butterfly plate realizes the single eccentric manufacturing process and the use function of variable eccentricity.
There is an over-position stopper for the butterfly plate in the inner cavity of the valve body to ensure that the butterfly plate is not in place when it is closed.
Bushings are used between the upper and lower valve shaft holes of the valve body cavity and the upper and lower valve shaft holes of the butterfly plate to prevent large particles in the medium from entering the valve shaft holes.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife 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

Features and application area of double eccentric butterfly valve

July 24, 2020

Double eccentric butterfly valve is also called high-performance butterfly valve. It is mainly used for drainage of water plants, power plants, steel smelting, chemical

5 double-eccentric-butterfly-valve-2

industry, water source engineering, environmental facility construction, etc. It is especially suitable for water pipelines and used as regulation and interception equipment. Compared with the centerline butterfly valve, the double eccentric butterfly valve is more resistant to high pressure, has a longer life and good stability.
Another name: high performance butterfly valve
Applicable area: water plant, power plant, steel mill smelting, chemical industry
Features: Longer life and good stability

use of double eccentric butterfly valve:
Double eccentric butterfly valve is also called high-performance butterfly valve. It is mainly used for drainage of water plants, power plants, steel smelting, chemical industry, water source engineering, environmental facility construction, etc. It is especially suitable for water pipelines and used as regulation and interception equipment. Compared with the centerline butterfly valve, the double eccentric butterfly valve is more resistant to high pressure, has a longer life and good stability. Compared with other valves, the larger the caliber, the lighter the material, and the lower the cost. But because there is a butterfly plate in the middle and the flow resistance is large, a butterfly valve smaller than DN200 is meaningless.

working principle of double eccentric butterfly valve:
The double eccentric butterfly valve is further improved on the basis of the single eccentric butterfly valve. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved. The scraping is greatly reduced, and at the same time, the double eccentric butterfly valve can also use a metal seat, which improves the application of the butterfly valve in the high temperature field.

Structural features
1 Reasonable design, compact structure, easy assembly and disassembly, and easy maintenance.
2 The eccentric structure is adopted to reduce the friction of the sealing ring and prolong the service life of the valve.
3 Completely sealed, zero leakage. Can be used in ultra-high vacuum conditions
4 Replace the valve plate sealing ring, butterfly plate, shaft and other materials, which can be applied to a variety of media and different temperatures

Centerline flange butterfly valve

July 23, 2020

The centerline flange butterfly valve is a high-quality soft-sealed valve. Mainly by the fully lined rubber valve body. The disc plate, valve stem, operating mechanism

U type flange butterfly valve (16)

and other parts have the characteristics of simple structure, good corrosion resistance, light operating torque and high reliability.

Overview of Centerline flange butterfly valve:
The centerline flange butterfly valve is widely used in tap water system, industrial water system, sewage treatment, metallurgy, petrochemical and other industries to cut off and adjust pipeline media. It is also suitable for corrosive systems (such as seawater treatment, etc.) Used for cutting off and adjusting.

Features of Centerline flange butterfly valve:

Excellent corrosion resistance
The inner wall of the valve body adopts an integral rubber vulcanization structure, which completely isolates the contact between the medium and the valve body metal. In addition to the corrosion-resistant disc plate, the valve has excellent anti-corrosion performance;
Low flow resistance
The disc version adopts a pancake-like structure, coupled with a full-bore valve seat, the valve has a very low flow resistance;
Light operating torque
The rubber valve seat is vulcanized on the valve body as a whole, and the valve seat will not be displaced or moved during the valve opening and closing process. When the valve is fully closed, the compression amount of each valve seat is uniform, and the valve seat has a lower operating torque;
Reliable disc plate and shaft connection
The connection between the disc and the shaft adopts a special pin structure, which is firm and reliable;

Diversified operation forms of Centerline flange butterfly valve:
The valve can be equipped with worm gear drive, handle drive, electric, pneumatic and other drive modes to meet customer needs.

technical parameter of Centerline flange butterfly valve:
Valve connection form: double flange
Nominal valve size: DN50-DN1200
Pressure rating PN6-PN25

Executive standard: API, DIN, BS, EN, GB and other international standards.
Design and Manufacture Conform to EN 593, API609
Flange dimensions Conform to EN 1092-2 PN10
Face to Face dimensions Conform to EN558 series
Topwork’s dimensions Conform to ISO5211
Testing Conform to API598, EN12266-1
Tanghai Valve is the best manufacturer of flange butterfly valve in China. We produce the best quality products with competitive low prices. Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, GB and other international standards. The main products are butterfly valves, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…), etc. Our products are widely used in various fields such as marine industry, shipbuilding, petrochemical , metallurgy, water treatment, fire fighting, water supply and drainage, etc. The company has won unanimous recognition and praise from customers with high quality and good reputation.

Related Information of flange butterfly valve

July 23, 2020

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

U-type flange butterfly valve, ductile iron, DI, center line,

If the butterfly valve is required to be used as a flow control, the main thing is to correctly select the size and type of the valve. 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 used in cooling water systems of thermal power stations.

The commonly used butterfly valves include wafer butterfly valves and flange butterfly valves. Wafer type butterfly valve uses double-head bolts to connect the valve between two pipe flanges. Flange type butterfly valve has flanges on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flanges.

When flange butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop produced by the valve is small, so it has better flow control characteristics. The butterfly valve has two sealing types: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.

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

If the butterfly valve is required to be used as a flow control, the main thing is to correctly select the size and type of the valve. 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 used in cooling water systems of thermal power stations.

The commonly used butterfly valves include wafer butterfly valves and flange butterfly valves. Wafer type butterfly valve uses double-head bolts to connect the valve between two pipe flanges. Flange type butterfly valve has flanges on the valve, and bolts are used to connect the flanges at both ends of the valve to the pipe flanges.

Features and structure drawings of flange butterfly valve

July 23, 2020

The main features of flange butterfly valve are:

Small and light, easy to disassemble and repair, and can be installed in any position.
U type flange butterfly valve (2)
The structure is simple and compact, the operating torque is small, and the 90° turn to open quickly.
The flow characteristics tend to be straight, and the regulation performance is good.
The connection between the butterfly plate and the valve stem adopts a pinless structure, which overcomes possible internal leakage points.
The outer circle of the butterfly plate adopts a spherical shape, which improves the sealing performance and prolongs the service life of the valve. It still maintains zero leakage after opening and closing more than 50,000 times under pressure.
The seal can be replaced, and the seal is reliable to achieve two-way sealing.
The butterfly plate can be sprayed with a coating layer, such as nylon or PTFE, according to user requirements.
The valve can be designed as flange connection and wafer connection.
The driving mode can be manual, electric or pneumatic.

Flange butterfly valves are suitable for water supply and drainage, sewage, food, heating, gas, ships, hydropower, metallurgy, energy systems, textiles and other industries with a temperature of ≤120℃ or ≤150℃ and a nominal pressure of ≤1.6MPa. They are especially suitable for two-way sealing and In occasions where the valve body is prone to rust, it is used as a flow adjustment and interception medium.

Internal structure diagram of flange butterfly valve: see attached below

Clamp flange connection sequence:
1. Piping: Use a pipe cutter or a grinding wheel cutting machine to cut the stainless steel pipe vertically according to the required length, trim the end burr, and make it round;

2. Welding: The left and right tapered flange flange pieces (with grooves, specially used for embedding the flange gasket on both sides) are respectively welded to the two piping ports that need to be connected by argon tungsten arc welding (TIG welding) ；

3. Gasket: double-sided flange gaskets are lined between the left and right flanges;

4. Fastening: clamp the two flanges with a clamp, and then use a fastening screw (hexagon socket bolt) to clamp the flange or fasten the handle (one end of the external thread is connected with the internal thread of the handle, and one end is flexibly connected with a fixed rivet) .

Executive standard: API, DIN, BS, EN, GB and other international standards.

Tanghai Valve is the best manufacturer of flange butterfly valve in China. We produce the best quality products with competitive low prices. Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, GB and other international standards. The main products are butterfly valves, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…), etc. Our products are widely used in various fields such as marine industry, shipbuilding, petrochemical, metallurgy, water treatment, fire fighting, water supply and drainage, etc. The company has won unanimous recognition and praise from customers with high quality and good reputation.

Introduction of Flange butterfly valve

July 23, 2020

The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. Moreover, it can be opened and closed quickly by rotating

Double flange butterfly valve (3)

90°, and the operation is simple. At the same time, the valve has good fluid control characteristics. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When the rotation reaches 90°, the valve is fully opened. When the flange butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is small, so it has better flow control characteristics. The butterfly valve has two sealing types: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.
Butterfly valves are divided into U type flange butterfly valves and double flange butterfly valves.

Introduction of flange butterfly valve:
The center of rotation of the butterfly plate of the flange butterfly valve (ie the center of the valve stem) is located on the center line of the valve body and the sealing surface section of the butterfly plate. The valve seat is made of synthetic rubber. When closed, the outer circular sealing surface of the butterfly plate squeezes the synthetic rubber valve seat, which makes the valve seat elastically deformed and forms an elastic force as the sealing pressure to ensure the sealing of the butterfly valve. Well-known domestic manufacturers include Shanghai Quangong Valve Equipment Co., Ltd. and Hunan Xinxing Hydropower Equipment Co., Ltd. Its company is a designated management and production enterprise by the Ministry of Machinery Industry, the Ministry of Chemical Industry, and China National Chemical Equipment Corporation. Its products have certain price advantages and technical advantages in the industry.

The sealing structure of the flange butterfly valve adopts polytetrafluoroethylene and synthetic rubber to form a composite valve seat. Its characteristic is that the elasticity of the valve is still provided by synthetic rubber and uses the characteristics of low friction coefficient, not easy to wear, and not easy to aging, so that The life of the butterfly valve is improved.

The sealing principle and structural characteristics of flanged butterfly valves are the same as those of ordinary centerline butterfly valves.

The sealing structure of flange butterfly valve adopts polytetrafluoroethylene, synthetic rubber and phenolic resin to form a composite valve seat, which makes the valve seat more elastic and stronger. At the same time, the butterfly plate is fully covered with PTFE, so that the butterfly plate has strong corrosion resistance.

Its sealing principle and structural characteristics are the same as ordinary centerline butterfly valve.

Difference between Soft seal gate valve and hard seal gate valve

Difference between soft seal butterfly valve and hard seal butterfly valve

Triple eccentric multi-level hard sealing flange butterfly valve

Installation instructions of double eccentric butterfly valve

Classification and features of Eccentric butterfly valves

Features and application area of double eccentric butterfly valve

Centerline flange butterfly valve

Related Information of flange butterfly valve

Features and structure drawings of flange butterfly valve

Introduction of Flange butterfly valve

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