butterfly valve manufacturer Archives

Vulcanized vs soft seated/back-up butterfly valve

June 17, 2021

The difference between rubber-lined butterfly valve and rubber butterfly valve (illustration)
The difference between a rubber-lined butterfly valve and a rubber butterfly valve, and the difference between a rubber-lined butterfly valve and a plastic-lined butterfly valve. The rubber-lined butterfly valve uses a high-temperature method to vulcanize the rubber and the valve body into one body. It has very high corrosion resistance and is generally used. To control some corrosive fluids with strong acidity and alkalinity. The rubber butterfly valve is a butterfly valve whose seal is a rubber seal, which is generally called a valve seat, and is separately installed into a whole.

Fluorine lined butterfly valve-PTFE-WAFER (8)

At normal temperature, the abrasion resistance of natural soft rubber is much better than that of nitrile rubber, but their high temperature resistance is the highest limit within 80 degrees, and it is not suitable for use if it exceeds.
The difference between a fully lined butterfly valve and a half lined butterfly valve:
1. Semi-lined butterfly valve means: the butterfly valve is not lined with rubber, but the place where the butterfly valve is connected to the valve body is lined with rubber;
2. Fully lined butterfly valve means: the butterfly plate of the butterfly valve and the part connected with the valve body are lined with rubber. The difference between rubber-lined butterfly valve, fluorine-lined butterfly valve and plastic-lined butterfly valve: rubber-lined butterfly valve and fluorine-lined butterfly valve are only one kind of plastic-lined butterfly valve.

wafer type butterfly valve (6)

The sealing materials in the rubber-lined butterfly valve are:
Applicable temperature of hard rubber NR: -10℃~85℃,
Applicable temperature of soft rubber BR: -10℃~85℃,
Suitable temperature for butyl rubber IIR: -10℃~120℃,
Applicable temperature of neoprene CR: -10℃~105℃;
The sealing materials in the fluorine-lined butterfly valve are:
Use temperature of polyperfluoroethylene FEP (F46): -85℃~150℃,
Polytetrachloroethylene PTFE (F4) operating temperature: -200℃~180℃,
Polytrifluoroethylene PCTEF (F3) operating temperature: -195℃~120℃,
Polypropylene: RPP operating temperature: -14℃~80℃,
Polyvinyl chloride: rigid) PVC service temperature: 0℃-55℃,
Polyvinylidene chloride PVDF (F2) operating temperature: -70℃~100℃,
Polyolefin: PO Operating temperature: -58℃~80℃.

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

pneumatic fluorine-lined butterfly valve vs pneumatic hard-sealed butterfly valve

June 16, 2021

The difference between pneumatic fluorine-lined butterfly valve and pneumatic hard-sealed butterfly valve
Pneumatic butterfly valve is an important execution unit with relatively large usage in industrial pipelines. Compressed air is used as the power source to operate the valve opening and closing, and the execution speed is very fast, usually only a few seconds! Pneumatic butterfly valve has simple structure, convenient operation and low cost. It can not only be used for quick shut-off, but also can be matched with valve positioner to receive relevant signals to achieve adjustment and control of pipeline medium pressure, flow, temperature and other parameters!

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

There are many types of pneumatic butterfly valves, which can fully meet the requirements of various working conditions, and can also customize the required butterfly valve products according to customer needs. Pneumatic fluorine-lined butterfly valve and pneumatic hard-sealed butterfly valve are two commonly used types. The medium and pressure temperature used are different. The control mode of the two is the same, but the sealing structure is completely different. Pneumatic fluorine-lined butterfly valve is suitable For pipelines that require sealing and contain corrosive media, but the pressure and temperature should not be too high, pneumatic hard-sealed butterfly valves can be used in various pressure and temperature ranges, with long service life, but poor sealing effect!

1. From the structure:
The hard sealing butterfly valve refers to that both sides of the sealing pair are made of metal materials or other harder materials. For soft sealing butterfly valves, the two contacting sealing surfaces can be separate or all of soft materials. For example, fluorine-lined butterfly valve means that the butterfly plate and valve seat are both wrapped in PTFE;
2. From the sealing performance:

Fluorine lined butterfly valve-PTFE-WAFER (8)

The advantage of soft-sealed fluorine-lined butterfly valve is good sealing performance, but the disadvantage is that it is easy to age, wear, and has a short service life. The hard seal butterfly valve has a long service life, but the sealing performance is relatively worse than that of the soft seal.
3. From the conditions of use:
The soft-sealed fluorine-lined butterfly valve is used in normal temperature and pressure environment, and the hard-sealed butterfly valve can be used in low temperature, normal temperature, high temperature and other environments. Generally, it can be used for higher pressure, but the soft seal is not. However, the fluorine-lined butterfly valve has super corrosion resistance!
4. From the manufacturing point of view:
As for manufacturing, from a principle point of view, there is little difference between the two, mainly the difference in valve seats. The soft-seal fluorine-lined butterfly valve is a non-metallic structure, and the hard-seal butterfly valve is a metal structure. The hardness relationship between metals and the workmanship must be considered. Situation, what medium to go and so on. The choice between pneumatic fluorine-lined butterfly valve and pneumatic hard-sealed butterfly valve is mainly based on the process medium, temperature and pressure. Generally, the medium contains solid particles and is worn, or the temperature is higher than 200 degrees. It is best to choose hard-sealed butterfly valves!
Related knowledge: Pneumatic butterfly valve working principle diagram; Pneumatic butterfly valve model compilation method

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

The working principle of butterfly valve (picture)

June 15, 2021

Working principle of butterfly valve:
The butterfly valve is a valve that opens and closes according to the rotation of the valve stem, while driving the disc plate to rotate. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, mainly by rotating the disc plate 90° for flow control. When the disc reaches 90°, the valve is in a fully open state, and the angle of the disc can be changed to adjust the medium flow. It is generally installed in the

U-type-flange-butterfly-valve-2

diameter direction of the pipe. The butterfly valve and the valve stem have no locking ability. In order to effectively adjust the flow, a worm gear reducer is required. The butterfly valve with a worm gear reducer not only makes the butterfly valve self-locking, but also changes the operating performance of the butterfly valve and adjusts the medium flow more accurately. .
Features of butterfly valve:
(1) Simple structure and small size. Due to its compact structure, short structure length, small size and light weight, it is suitable for large diameters.
(2) The fluid resistance is small. When fully opened, the effective flow area of the valve seat channel is large, so the fluid resistance is small.
(3) The opening and closing is convenient and rapid, the adjustment performance is good, and the butterfly plate rotates 90. Both can complete the opening and closing. The flow can be controlled in stages by changing the rotation angle of the butterfly plate.

(4) The opening and closing moment is small, because the discs on both sides of the rotating shaft are basically the same under the action of the medium, and the direction of the torque is opposite, so the opening and closing is labor-saving.
(5) The low-pressure sealing performance is good, and the sealing surface material is generally rubber or plastic, so the sealing performance is good. Limited by the material of the sealing ring, the operating pressure and operating temperature range of the butterfly valve is relatively small. However, the working pressure and working temperature range of the hard seal butterfly valve have been greatly improved.

butterfly valve working diagram-3D GIF animated presentation

1. The butterfly valve has a small flow resistance when it is fully opened. When the opening is between about 15° and 70°, it can carry out sensitive flow control. Therefore, the application of butterfly valves is very common in the field of large-diameter adjustment. Since the movement of the butterfly plate of the butterfly valve is wiping, most butterfly valves can be used for media with suspended solid particles. Depending on the strength of the seal, it can also be used for powder and granular media.
2. The butterfly valve is suitable for flow adjustment. Because the pressure loss of the butterfly valve in the pipe is relatively large, about three times that of the gate valve, when selecting the butterfly valve, the influence of the pressure loss of the piping system should be fully considered, and the strength of the butterfly plate to withstand the pressure of the pipeline medium when it is closed should also be considered. . In addition, it is necessary to consider the limitation of the working temperature that the elastic valve seat material can withstand at high temperatures. To
3. The structural length and overall height of the butterfly valve are small, the opening and closing speed is faster, and it has good fluid control characteristics. The structure principle of butterfly valve is most suitable for making large-diameter valves. When a butterfly valve is required to control flow, the most important thing is to correctly select the specification and type of the butterfly valve so that it can work properly and effectively.
Related knowledge: Principles of butterfly valve structure
Related products: Electric switching butterfly valve Electric regulating butterfly valve

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

Representation method of butterfly valve model

June 11, 2021

Representation method of butterfly valve model in China:
Butterfly valve model compilation instructions, butterfly valve model representation method, Butterfly valve model compilation instructions, butterfly valve coding /naming method:

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

There are countless types and specifications of butterfly valves for industrial pipelines. The increase in additional conditions for butterfly valves, the difference in connection methods, the upgrade of transmission methods, the changes in structural forms, and the increased requirements for temperature, pressure and corrosion resistance on materials are for the convenience of users in the industry. Have more knowledge about the correct selection of butterfly valves and the purchase of butterfly valves. For this purpose, Duoyi Valve provides the latest butterfly valve model compilation instructions, hoping to be helpful to the majority of users.

Butterfly valve model representation method:
Additional code of butterfly valve: BD: thermal insulation butterfly valve, SD: telescopic butterfly valve, TLD: desulfurization butterfly valve, DH: check butterfly valve, DKS: fast butterfly valve, FDBD: square louver butterfly valve;
The code of the butterfly valve: D: represents the butterfly valve;
Transmission form code: manual (omitted), 3: means turbine drive, 6: means pneumatic drive, 7: means hydraulic, 9: means electric;
Connection code code: 4: flange type, 6: welding, 7: pair clamp type;

Structure code code: 1: means centerline type, 2: means double eccentricity, 3: means triple eccentricity, 4: means variable eccentricity, 5: means single eccentricity;
Sealing material code: H: stainless steel, X: rubber, F: polytetrafluoroethylene, FX: composite rubber, M: Monel alloy, Y: cemented carbide, W: valve body directly processed;
Pressure grade code: 10=PN1.0Mpa, 16=PN1.6, 25=PN2.5, 40=PN4.0, PN is the code of domestic pressure, MPA is the unit of pressure, one kilogram is equal to 0.1Mpa; Class150LB=1.6 mpa, 300LB=2.5-4.0mpa, Class is the American standard code, LB is the American standard pound unit.
Shell material code: C: cast steel, P: stainless steel 304, R: stainless steel 316, AL: special alloy steel, Z: cast iron, Q: ductile iron, N: nylon.
The above are common codes related to butterfly valves. For products that need to be customized due to special working conditions, they can be selected according to the design plan.
Examples of butterfly valve model compilation:
D943H-16C electric triple eccentric butterfly valve
D: Represents butterfly valve;
9: Indicates that the transmission mode is electric;
4: The connection method is flange connection;
3: The structure is triple eccentric;
H: The sealing material is stainless steel;
16: Indicates that the nominal pressure is 1.6MPa;
C: Indicates that the valve body material is cast steel.
Related valve model: Valve model Globe valve model Check valve model Gate valve model Regulating valve model Ball valve model

See complete coding method on: Valve model establishment and meaning

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

Flange telescopic butterfly valve application | advantages and disadvantages | installation instructions

June 10, 2021

Flange telescopic butterfly valve application|advantages and disadvantages|installation instructions
Flange telescopic butterfly valve application:
The butterfly plate of the flange telescopic butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the telescopic 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. Applicable temperature≤80℃, used in petroleum, chemical, food, medicine, textile, papermaking, electric power, water supply and drainage, gas pipelines, as the function of regulating flow and intercepting medium, and has the function of compensating for thermal expansion and contraction of pipelines.

Double flange butterfly valve (16)

Advantages and disadvantages of flange telescopic butterfly valve:
Flange retractable butterfly valve (the structural length can be extended within a certain range), which not only brings convenience for valve disassembly, but also relieves pipeline stress and protects the valve. At the same time, it also condenses the installation method of butterfly valve plus retractor, and space More compact. Normally, this type of valve does not require special maintenance, and only needs to be regularly observed for leakage and pull-off in the telescopic part. The initial cost of flange expansion butterfly valve is lower than the installation method of flange butterfly valve plus expansion, but considering the maintenance cost in the future, the gain is not worth the loss.
If the sealing part of the butterfly valve is damaged and the sealing ring cannot be replaced and the butterfly valve needs to be scrapped, then the telescopic part will be scrapped together, resulting in greater loss. For example, when the sealing part of the butterfly valve needs maintenance, only the compression and expansion part cannot realize the valve-free online maintenance. However, the installation method of the butterfly valve and the expansion device has a great advantage. Only the expansion device needs to be removed, that is, manual Large maintenance space to realize valve free maintenance (butterfly valve is heavy, retractor is light, and labor intensity is low).
Precautions for installation of flange telescopic butterfly valve:
1. It is strictly forbidden to disassemble the butterfly valve of the disintegrated telescopic flange at the pipeline construction site; it is strictly forbidden to lengthen and shorten the telescopic butterfly valve repeatedly at the site.
2. The pipes at both ends of the telescopic valve must be concentric, and the two flange surfaces on the pipe must be parallel;
3. Flange fixing bolts should be tightened symmetrically, please do not forcibly tighten flange fixing bolts unilaterally;
4. The telescopic tube is installed behind the valve;
5. The expansion part of the expansion valve shall not be installed at the corner of the pipeline or at the end of the pipeline.
6. The telescopic flange butterfly valve must be placed flat before installation, and do not bump it at will;
7. The structural length of the telescopic flange butterfly valve is the minimum length when it leaves the factory, and when installed, it is pulled to the installation length (ie the design length);
8. When the length between the pipelines exceeds the installation length of the telescopic butterfly valve, please adjust the pipeline interval and do not force the telescopic valve to avoid damage to the telescopic valve;
9. The butterfly valve of the telescopic flange butterfly valve can be installed at any position. When used for temperature compensation, after the installation of the pipeline, brackets should be added along the two ends of the pipeline axis to prevent the telescopic valve telescopic tube from being pulled out. The support force of the bracket is calculated according to the following formula , It is strictly forbidden to remove the bracket during operation;
10. The telescopic flange butterfly valve does not do temperature compensation. At the same time, it is only used for installation, replacement, and maintenance. When the valve is convenient for use, it can be limited by bolts, and the telescopic flange butterfly valve can be clamped symmetrically to prevent the telescopic tube from being pulled out and damaging the telescopic butterfly valve and piping devices or buildings. Things. The bolt diameter can be calculated according to the flange bolt diameter, its bolt strength and test pressure and pipeline tension, according to the above formula. The limit bolts are strictly prohibited to be removed during operation (bolts are provided separately).

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

What is the material of the butterfly valve stem?

August 17, 2020

Stem material classification:
During the opening and closing of the butterfly valve, the valve stem bears the forces of tension, pressure and

buttefly valve stem shaft parts (6)

torsion, and is in direct contact with the medium. At the same time, there is relative frictional movement with the packing. Therefore, the valve stem material must ensure that there is enough at the specified temperature Strength and impact toughness, a certain degree of corrosion resistance and scratch resistance, and good manufacturability. The commonly used stem materials are as follows.

1. When carbon steel is used in water and steam medium with low pressure and medium temperature not exceeding 300℃, A5 ordinary carbon steel is generally used. When used in water and steam medium with medium pressure and medium temperature not exceeding 450℃, 35 high-quality carbon steel is generally used.

2. When alloy steel is used for medium pressure and high pressure, and the medium temperature does not exceed 450 ℃ water, steam, petroleum and other media, 40Cr (chromium steel) is generally used. 38CrMoALA nitriding steel can be used when it is used in water, steam and other media with high pressure and medium temperature not exceeding 540℃. 25Cr2MoVA chromium molybdenum vanadium steel is generally used when used in high pressure steam medium with medium temperature not exceeding 570℃.

3. Stainless acid-resistant steel S is used for non-corrosive and weakly corrosive media with medium and high pressure and medium temperature not exceeding 450℃. 1Cr13, 2Cr13, 3Cr13 chromium stainless steel can be selected. When used in corrosive media, stainless acid-resistant steel such as Cr17Ni2, 1Cr18Ni9Ti, Cr18Ni12Mo2Ti, Cr18Ni12Mo3Ti, and PH15-7Mo precipitation hardening steel can be selected.

4. When heat-resistant steel is used for high-temperature valves whose medium temperature does not exceed 600℃, 4Cr10Si2Mo martensitic heat-resistant steel and 4Cr14Ni14W2Mo austenitic heat-resistant steel can be selected.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest valve stem/shaft manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: 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…)

What is the material of the main parts of the butterfly valve?-(2)

August 17, 2020

Selection of valve sealing material:

Sealing surface material: The sealing surface is the most critical working surface of the valve. The quality of the

marine valve seat

sealing surface is related to the service life of the valve. Generally, the sealing surface material should consider factors such as corrosion resistance, scratch resistance, erosion resistance, and oxidation resistance. Usually divided into two categories:

(1) Soft materials of butterfly valve:

Rubber (including nitrile rubber, fluorine rubber, etc.)
Plastics (polytetrafluoroethylene, nylon, etc.)

(2) Hard sealing material of butterfly valve:

Copper alloy (used for low pressure valves)
Chrome stainless steel (used for ordinary high and medium pressure valves)
Stellite alloy (used for high temperature and high pressure valves and strong corrosion valves)
Nickel-based alloy (used for corrosive media)

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: 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…)

Introduction of U-shaped flange butterfly valve

July 27, 2020

What is U-shaped flange connection butterfly valve?
The U shaped 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

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

by rotating 90°, and the operation is simple. At the same time, the valve has good fluid control characteristics.
The butterfly plate of the U type 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.
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 90°, and the operation is simple. At the same time, the valve has good fluid control characteristics. 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.
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 choose 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, water treatment, etc., but also used in cooling water systems of thermal power stations.
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 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. 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, water treatment, etc., but also used in cooling water systems of thermal power stations.
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.

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

Comparison and analysis of the performance of the wafer butterfly valve

July 20, 2020

With the same nominal pressure and nominal diameter, ordinary which has better tightness and is not easy to leak? butterfly valve or gate valve?

wafer type butterfly valve, NBR seat (11)

The airtightness of the gate valve is better than that of the butterfly valve, but there are also manufacturers’ butterfly valves that have better airtightness.
The gate valve is large in size and takes up a lot of space.
The butterfly valve is small in size and takes up little space.

When selecting concretely, the temperature of the medium, the sealing of the valve and the packing should also be considered.
The specification stipulates that the butterfly valve with a nominal diameter greater than 50 is used.

Wafer butterfly valve is a national key new product. The high-performance manual butterfly valve adopts a double eccentric and a special oblique cone oval sealing structure. It solves the shortcoming of the traditional eccentric butterfly valve that the sealing surface is still in sliding contact friction at the moment of opening and closing 0°～10°, and the sealing surface of the butterfly plate is separated at the moment of opening, and the effect of sealing when the contact is closed is achieved to extend the service life and maximize the sealing performance.

Tanghai Valve is the best manufacturer of wafer-type butterfly valve in China. We produce the best quality products with competitive low prices.

13 gate-valve-5

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.

We have established long-term and stable business relationships with many multinational companies. Our products are exported to Europe, the United States, Australia, and the Middle East, Southeast Asia and other countries and regions. The quality of our products has been widely recognized by customers, and has been trusted and praised by customers. Gradually we have established a close technical partnership with customers from various countries.

We are committed to “Build a top valve enterprise; Be a reliable partner!”

Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

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

Posts

Vulcanized vs soft seated/back-up butterfly valve

pneumatic fluorine-lined butterfly valve vs pneumatic hard-sealed butterfly valve

The working principle of butterfly valve (picture)

Representation method of butterfly valve model

Flange telescopic butterfly valve application | advantages and disadvantages | installation instructions

What is the material of the butterfly valve stem?

What is the material of the main parts of the butterfly valve?-(2)

Introduction of U-shaped flange butterfly valve

Classification and features of Eccentric butterfly valves

Comparison and analysis of the performance of the wafer butterfly valve

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