butterfly valve manufacturer Archives

electric fluorine-lined butterfly valve vs electric metal seated butterfly valve

August 2, 2021

The difference between electric fluorine-lined butterfly valve and electric hard seal butterfly valve
Electric butterfly valve is one of the most commonly used valves in industrial pipelines in recent years. In addition to ordinary opening and closing, it can also be used to adjust and control the pressure, flow, temperature and other parameters of various water, liquid, gas and other fluids. An important execution unit in the field of automation control, is widely used in chemical, electric power, petroleum, metallurgy, steam, environmental protection, fire-fighting systems and other occasions! In addition, there are many types of electric butterfly valves and various control modes, which can meet the requirements of various working conditions!

Fluorine lined butterfly valve-PTFE-WAFER (10)

Electric fluorine-lined butterfly valves and electric hard-sealed butterfly valves are the two most commonly used types of butterfly valves. The applicable medium and pressure temperature are completely different! But many people’s choice between the two often seems a bit uncertain! In the simplest terms, the two control modes are the same, the difference is the sealed structure. The electric fluorine-lined butterfly valve is suitable for corrosive media, but it can only be used at room temperature and pressure. The electric hard seal butterfly valve can be used for various pressures. temperature range! The detailed differences are as follows:
Electric fluorine-lined butterfly valve Electric hard-sealed butterfly valve
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;

D943H-16C-metal seated stainless steel electric triple offset butterfly valve

2. From the sealing performance:
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.
Related knowledge: Working principle diagram of electric butterfly valve Selection of electric wafer butterfly valve and flange 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, API

Single eccentric|double eccentric|triple eccentric butterfly valve structure principle (diagram)

July 30, 2021

The evolution of butterfly valve sealing structure: single eccentric butterfly valve, double eccentric butterfly valve and triple eccentric butterfly valve

Butterfly valves have been widely used due to their low cost, small size, light weight and long life. With the development of my country’s industry, various industries have more and more stringent requirements for the performance of equipment, especially in some gas pipelines or other hazardous material pipelines, the butterfly valve must achieve zero leakage, so the sealing structure design of the butterfly valve has always been important Research topics.

With the rapid development of modern industrial technology, butterfly valves are widely used in pipeline control systems, especially large-diameter pipeline control systems where other control valves are difficult to apply. Generally, the valve seat of the butterfly valve is a fixed type, and its materials are polymer and metal. The polymer valve seat is mainly suitable for working conditions with lower temperature. Although the metal seat butterfly valve can meet the higher temperature and pressure However, the elasticity of the metal valve seat is lower than that of the polymer valve seat, and the sealing performance is poor. The improvement of various performances of butterfly valves is closely related to its continuous improvement. For example, the development of butterfly valve sealing structure technology has successively experienced the evolution process of ordinary butterfly valve, single eccentric butterfly valve, double eccentric butterfly valve and triple eccentric butterfly valve.

Since the rotation center of the butterfly plate (that is, the center of the valve shaft) and the sealing section of the butterfly plate are set eccentrically according to a, the butterfly plate sealing surface gradually separates from the valve seat sealing surface during the opening process of the butterfly valve, and the butterfly plate rotates to 20°～25° , The sealing surface of the butterfly plate is completely separated from the sealing surface of the valve seat. When the valve is fully opened, a gap x is formed between the two sealing surfaces, so that the relative mechanical wear and extrusion between the two sealing surfaces of the butterfly valve is greatly reduced during the opening and closing process. Ensure the sealing of the butterfly valve.

Since the rotation center of the butterfly plate (that is, the center of the valve shaft) and the center line of the valve body are offset by size b on the basis of the single eccentric butterfly valve, the sealing surface of the butterfly plate will be faster than the single eccentric sealing butterfly valve during the opening process of the butterfly valve. When the butterfly plate rotates to 8°～12°, the butterfly plate sealing surface is completely separated from the valve seat sealing. When it is fully opened, a larger gap y is formed between the two sealing surfaces. This type of butterfly valve is designed , Which greatly reduces the mechanical wear and extrusion deformation between the two sealing surfaces, and improves the sealing performance of the butterfly valve.

There are different types of eccentric sealing butterfly valves, and the fields of application and their respective characteristics are naturally different. But fundamentally speaking, the basic principles of eccentric sealing butterfly valves are similar.

Structural characteristics of single eccentric butterfly valve:

single eccentric butterfly valve structure diagram

1. The center of rotation of the disc plate (that is, the center of the valve shaft) is located on the center line of the valve body, and an A-size offset is formed on the sealing section of the valve plate. The single eccentric butterfly valve is that the rotation center of the disc plate is on the center line of the valve body, and the valve plate deviates a distance from the sealing surface, which is suitable for soft sealing.
2. When the valve is closed, the valve seat and the sealing surface of the valve plate are in a relatively interference contact state. To achieve the seal, it is mainly by pressing the sealing ring to expand in the peripheral direction to produce the sealing specific pressure and the pipeline pressure against the valve plate. It can only be sealed in one direction because of the strong force.
3. When the valve is opened, the contact side of the valve plate and the valve seat is separated from the valve seat, and the other side is always two-point contact along the axial direction of the half circumference. Repeated opening and closing of the sealing ring is easy to be damaged, which affects the sealing performance. It is impossible to achieve a metal seal.
4. From a geometric point of view, it is obvious that X does not exist in the above figure, and in turn there is a certain amount of interference.
Structural features of double eccentric butterfly valve:

double eccentric butterfly valve structure diagram

The center of rotation of the valve plate (that is, the center of the valve shaft) forms an offset of dimension A on the sealing section of the valve plate, and forms an offset of dimension B with the center of the valve body.
Since the center line of the valve seat and the center line of the valve body form a β angle offset on the basis of the double eccentric butterfly valve, the sealing surface of the butterfly plate immediately leaves the sealing surface of the valve seat at the moment of opening during the valve opening process of the butterfly valve. Only at the moment of closing does it contact and compress the seat sealing surface. When fully opened, a gap y is formed between the two sealing surfaces, which is the same as that of the double eccentric sealing butterfly valve. The design of this type of butterfly valve completely eliminates the mechanical wear and abrasion between the two sealing surfaces, making the butterfly valve more effective in its sealing performance and use. The life span has been greatly improved.

Structural features of triple eccentric butterfly valve:

triple eccentric butterfly valve structure diagram

The center of rotation of the valve plate (that is, the center of the valve shaft) forms an offset A on the sealing section of the valve plate, and an offset b from the center of the valve body; the centerline of the valve body sealing surface and the centerline of the valve seat (ie the centerline of the valve body) An angular offset of β is formed.
The uniqueness of the triple eccentric butterfly valve is that the stem shaft on which the butterfly plate is installed is a three-segment shaft structure. This three-segment shaft type valve stem has two shaft sections concentric, and the center line of the central shaft is deviated 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 it is close to closing, the butterfly plate moves a 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.
Related Knowledge: Common Sense of Eccentric Butterfly Valve

Related Products: Electric Triple Eccentric Butterfly Valve Pneumatic Triple Eccentric 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

Types and classifications of butterfly valves

July 30, 2021

Types and classifications of butterfly valves
Butterfly valves can be divided into offset plate type, vertical plate type, inclined plate type and lever type according

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

to the structure. According to the sealing form, it is divided into two types: relatively sealed type and hard sealed type. Soft-sealed butterfly valves generally use rubber ring seals, and hard-sealed butterfly valves usually use metal ring seals. According to the connection type, they are divided into flange connection and wafer connection. According to the transmission mode, they are divided into manual, gear transmission, pneumatic, hydraulic and electric. .
Due to the wide variety of butterfly valves, and in special working conditions, the butterfly valve products used are also different. Therefore, for this type of valve, you should choose the type separately from the engineer! According to common types and classifications, butterfly valves can be divided into the following forms:
(1) Classification by structure
1. Center sealing butterfly valve

Types of wafer butterfly valves

2. Single eccentric sealing butterfly valve
3. Double eccentric sealing butterfly valve
4. Triple eccentric sealing butterfly valve
(2) Classified by link method
1. Wafer butterfly valve
2. Flanged butterfly valve
3. Lug butterfly valve
4. Welded butterfly valve
(3) Classified by working temperature
1. High temperature. t>450 °C butterfly valve.
2. Medium temperature butterfly valve. 120 C<t<450 ℃ butterfly valve.
3. Normal temperature butterfly valve. A butterfly valve of 40C<t<120 °C.
4. Low temperature butterfly valve. One 100<t<一40 °C butterfly valve.
(4) Classified by sealing surface material
1. Soft sealing butterfly valve.
(1) The sealing pair is composed of non-metallic soft material to non-metallic soft material.
(2) The sealing pair is composed of metallic hard materials and non-metallic soft materials.
2. Metal hard sealing butterfly valve. The sealing pair is composed of a metal hard material to a metal hard material.
(5) Classified by work pressure
1. Vacuum butterfly valve, a butterfly valve whose working pressure is lower than the atmospheric pressure of the standard stack.
2. Low pressure butterfly valve, butterfly valve with nominal pressure PN<1.6MPa.
3. Medium pressure butterfly valve, butterfly valve with nominal pressure PN of 2.5-6.4MPa.
4. High-pressure butterfly valve, a butterfly valve with a nominal pressure PN of 10.0-80.0MPa.
5. Ultra-high pressure butterfly valve, butterfly valve with nominal pressure PN>100MPa.
(6) Classified by sealing form

Double offset-lug butterfly valve-D372F-150lbC (1)

1. Forced sealing butterfly valve.
(1) Elastic sealing butterfly valve. The specific pressure of the seal is generated by the elasticity of the valve seat or the valve plate when the valve plate squeezes the valve seat when it is closed.
(2) External torque sealing butterfly valve. The seal specific pressure is generated by the torque applied to the valve shaft.
2. Pressure-filled and sealed butterfly valve. The specific sealing pressure is generated by the pressure of the elastic sealing element on the valve seat or valve plate.
3. Automatic sealing butterfly valve. The sealing specific pressure is automatically generated by the medium pressure.
Related knowledge: Types of valves Types of regulating valves Types of stop valves Types of ball valves Types of gate valves

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

Structural characteristics of metal hard seal butterfly valve

July 29, 2021

Structural characteristics of metal hard seal butterfly valve
The metal hard seal butterfly valve is mainly composed of valve body, butterfly plate, valve shaft, valve body sealing ring, butterfly plate sealing ring, shaft sleeve, self-lubricating bearing, driving device and so on. The high-performance metal hard seal butterfly valve drives the valve shaft to rotate through various driving devices, and the pin shaft drives the butterfly plate to rotate within 90°, so that the butterfly plate is in the open or closed state, so as to achieve the purpose of connecting or cutting off. It is widely used in metallurgy, hydropower, thermal power, thermal power, urban water supply and drainage, farmland irrigation and drainage and other industries. The applicable medium is gas, steam, air, water, etc., in the pipeline system.

triple eccentric butterfly valve-lug

Structural features of metal sealing butterfly valve:
①The unique design of three-way eccentricity enables frictionless transmission between the sealing surfaces and prolongs the service life of the valve.
②The elastic seal is produced by the torque.
③The ingenious wedge-shaped design makes the valve have the function of automatic sealing as the valve closes tighter and tighter, and the sealing surface has compensation and zero leakage.
④Small size, light weight, light operation, easy to install.
⑤Pneumatic and electric devices can be configured according to user requirements to meet the needs of remote control and program control.
⑥The material of replacement parts can be applied to various media, and can be lining anti-corrosion (lining F46, GXPP, PO, etc.).
⑦The sealing ring is made of stainless steel, which has the dual advantages of metal hard seal and elastic seal. It has excellent sealing performance regardless of low temperature and high temperature.
The difference between metal hard seal butterfly valve and rubber seal butterfly valve:
The disadvantage of the rubber seal butterfly valve is that when it is used for throttling, cavitation will occur due to improper use, causing the rubber seat to peel off and damage. For this reason, the metal sealing butterfly valve has been developed internationally. The metal hard sealing butterfly valve is an eccentric metal sealing structure, and the sealing form is metal to metal sealing. The metal sealing ring can be exchanged for metal sealing, and the stainless steel plate and graphite composite plate sealing ring is sealing to metal. .

The high-performance elastic metal sealing 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 closing the contact is sealing, so as to extend the service life and maximize the sealing performance.
Related knowledge: the principle of butterfly valve structure
Related products: Electric hard-sealed butterfly valve Pneumatic hard-sealed 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

Pneumatic butterfly valve working principle diagram

July 28, 2021

Pneumatic butterfly valve working principle diagram
Pneumatic butterfly valve is a kind of general-purpose valve that is particularly widely used. Nowadays, many chemical industry, paper industry, coal industry, petroleum, medical, etc. will use valves, especially pneumatic valves, and if the use is relatively large, it must be Pneumatic butterfly valves are extremely common on many pneumatic pipelines! Especially in low-pressure large and medium-caliber pipelines, it is used more and more. The larger the diameter, the more economical and economical than other valves.

Double offset-butterfly valve-D972F-150lbC (1)

Pneumatic butterfly valves are so widely used because of their simple structure, easy maintenance, and rapid switching, which can not only improve work efficiency, but also reduce maintenance time. According to customer requirements, seal rings of different materials and parts of different materials can be selected to be suitable for different media and working conditions, so that the pneumatic butterfly valve can achieve great results.
Working principle of pneumatic butterfly valve:
The pneumatic butterfly valve uses compressed air as the power source, and drives the valve stem to control the disc-shaped butterfly plate to rotate around the axis. The initial position of the valve is determined according to actual needs. When the valve rotates 90° from the initial position, an action ends (by opening To off, or from off to on), otherwise, another action (from off to on, or from on to off) ends.
The execution speed of the pneumatic butterfly valve is relatively fast, it is not easy to be damaged due to jamming during the movement process, and does not require the hands of workers. It can not only be used as a cut-off valve, but also can be equipped with a valve positioner to achieve the function of regulating and controlling the pipeline medium. Pneumatic butterfly valve actuators are divided into single-acting and double-acting forms. The double-acting is vent opening and vent closing! Among them, the single-acting actuator has a spring return function, which can be

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

automatically closed or opened in the case of gas or power failure, with a high safety factor!
Related knowledge: dynamic diagram of butterfly valve working principle
Recommended products: Pneumatic regulating butterfly valve Pneumatic triple eccentric 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

electric wafer butterfly valve vs electric flange butterfly valve

July 27, 2021

The difference and selection of electric wafer butterfly valve and electric flange butterfly valve
As one of the most common valves in pipelines, electric butterfly valves are used to realize the on-off and flow control of various media in the pipeline system. They have been widely used in many fields such as petroleum, chemical industry, metallurgy, and hydropower. application. Then in the commonly used electric butterfly valve, it can be

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

divided into two kinds, electric wafer butterfly valve and electric flange butterfly valve, and these two kinds of valves have their own characteristics, and they are not the same in performance. They can be used in Different industries.

For these two kinds of valves, in addition to the different structural forms, if they are under the same parameters, the biggest difference is that the connection method is different, that is, the installation form is different, which depends on the site working conditions!

The difference between electric wafer butterfly valve and electric flange butterfly valve:
The thickness of the electric wafer butterfly valve is relatively thin compared to the flanged butterfly valve. There are no flanges at both ends of the valve body, but only a few guide bolt holes. The valve uses a set of bolts/nuts to connect with the flange of the pipe end, which is generally applicable. It is used in places where the space is relatively narrow or the pipeline is restricted. The advantage is that it is more convenient to disassemble, the valve cost is lower, and the space is small, but the disadvantage is that one sealing surface has a problem, and both sealing surfaces have to be disassembled!
Electric flange butterfly valve has flanges at both ends of the valve body, which are connected with pipeline flanges. Compared with wafer butterfly valves, the sealing performance is more reliable. It is generally used in places with larger diameters or higher pressures, but the cost is relatively good.

D943H-16C-metal seated stainless steel electric triple offset butterfly valve

Choice between the two:
However, there are still some things to pay attention to in the design. For example, wafer type valve bolts are generally relatively long. Under high temperature conditions, the expansion of the bolts may cause leakage, so it is not suitable for large pipe diameters under high temperature conditions. . Another example is the wafer butterfly valve generally cannot be used in the end of the pipeline and downstream needs to be disassembled, because when the downstream flange is removed, the wafer valve will fall off, in this case, it must be shortened separately. The flange type butterfly valve does not have the above problems, but the cost will be higher.
Related Electric butterfly valve series products View other butterfly valves

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

Butterfly valve use principle and installation instructions

July 22, 2021

Butterfly valve use principle and installation instructions
The relationship between the opening of the butterfly valve and the flow rate basically changes linearly. If it is used to control flow, its flow characteristics are also closely related to the flow resistance of the piping. For example, two pipelines are installed with the same valve diameter and form, but the pipeline loss coefficient is different, and the flow rate of the valve will also be very different.

butterfly valve working diagram-3D GIF animated presentation

If the valve is in a state with a large throttle range, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used outside 15°. When the butterfly valve is in the middle opening degree, the opening shape formed by the valve body and the front end of the butterfly plate is centered on the valve shaft, and the two sides form different states. Therefore, one side of the valve body and the valve plate form a nozzle-like opening, and the other side is similar to a throttle opening. The nozzle side has a much faster flow rate than the throttle side, and negative pressure will be generated under the throttle side valve. The rubber seal may fall off.

The operating torque of the butterfly valve has different values due to the different opening and closing directions of the valve. The horizontal butterfly valve, especially the large-diameter valve, due to the depth of water, the torque produced by the difference between the upper and lower water heads of the valve shaft cannot be ignored. In addition, when an elbow is installed on the inlet side of the valve, a bias flow is formed and the torque will increase. When the valve is in the middle opening, the operating mechanism needs to be self-locking due to the action of the water flow torque.

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

Butterfly valve structure principle and application analysis

July 21, 2021

Butterfly valve (also called flap valve) is a kind of regulating valve whose closing part is circular disc or disc, mainly composed of valve body, valve stem, disc and sealing ring. The valve body is cylindrical with short axial length and built-in butterfly plate. 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.

Double offset-flanged butterfly valve-D42F-150lbC (1)

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 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 inlaid on the valve body or attached to the periphery of the butterfly plate.
Butterfly valves with metal seals generally have a longer life than those with elastic seals, but it is difficult to achieve a complete seal. The metal sealing butterfly valve can adapt to higher working temperature, while the elastic sealing butterfly valve has 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 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.

Double eccentric-lug butterfly valve-D72F-150lbP-stainless steel (4)

Commonly used butterfly valves include wafer type butterfly valves and flange type 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.

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

Structural characteristics & features of flanged butterfly valves

July 8, 2021

The basic knowledge and structural characteristics of flange butterfly valves:
The flanged butterfly valve has introduced a self-sealing design concept, in which the connection between the disc and the valve shaft adopts a patented pull-out pin structure. The main features of the valve are reliable sealing, bi-directional sealing, and tight connection without loosening, so that the valve can be used for a long time. Its characteristics are as follows:

Double flange butterfly valve (16)

Two-way sealing
Generally, traditional butterfly valves cannot be sealed well under the working pressure in the opposite direction (not conducive to the sealing direction) due to their structural reasons. At present, the relevant national standards do not have mandatory regulations for two-way sealing. This is because:
1. Adopting the self-sealing design concept. The disc sealing ring is directly embedded in the disc in a zigzag shape with rubber, and there is no need to use pressure rings or bolts to fix, thus avoiding the uneven force of the sealing ring caused by the traditional bolt pressure plate type seal, which makes the bolts The problem of falling off and premature damage to the sealing ring. Under the action of the working pressure in the opposite direction, the sealing ring generates self-sealing force, which increases the specific pressure of the seal. The sealing ring compresses the valve seat. The greater the working pressure in the opposite direction, the greater the self-sealing force, so that the sealing ring and the valve seat The combination is tight to achieve the effect of two-way sealing.

triple offset butterfly valve-double flange- (4)

2. The disc has good rigidity and is not easy to deform. The disc of butterfly valve above DN300 is a double-plate truss flow-through structure, with small flow resistance and good rigidity. Under the working pressure in the opposite direction, it is not easy to deform, so that the sealing ring will not follow the disc Deformed and separated from the best sealing point of the valve seat, thus ensuring the sealing effect of the sealing ring.
3. Long life of rubber sealing ring
(1) Due to the self-sealing design concept, the small interference between the rubber ring and the stainless steel valve seat only maintains the initial seal, so the specific pressure required for the seal increases with the increase of the system pressure.
(2) In addition, there is a so-called “breathing” groove for rubber elastic retreat in the zigzag groove, so that the rubber has a certain expansion space when it is under pressure, so that it will not produce elastic fatigue during long-term work, so it is sealed The life of the ring is greatly increased compared with the traditional type.
Patent design withdrawal pin structure
Usually in the process of using the butterfly valve, due to the traditional pin connection, the pin passes through the center of the valve shaft, which not only reduces the strength of the valve shaft, but also creates a gap between the valve shaft and the valve shaft during long-term use, which will cause an impact when the valve is opened and closed. Load, this load is much greater than the load generated by the extrusion stress and shear stress under normal conditions. Often the pin is severely deformed or broken during use, which makes the valve closed or fails, and greatly reduces the valve Service life. If the newly produced valve adopts the US patent design withdrawing pin structure to replace the pin connection structure between the shaft and the valve disc, the withdrawal pin does not pass through the center of the valve shaft, not only does not weaken the strength of the shaft, but also connects with the valve shaft. The fitting surface is greatly increased. By tightening the withdrawal pin nut, a pre-tightening force is generated between the withdrawal pin and the valve shaft joint surface, so that the disc valve shaft is tightly combined without gaps, and it will not be used when opening and closing the valve. The impact load is generated, so that the valve flap rotates smoothly, thereby realizing reliable sealing.
Unique design of the bottom axial adjustment and locking device
In butterfly valves above DN300, considering the reliability of the self-weight seal of the butterfly plate, the position of the disc on the valve seat is in the best sealing state through precise adjustment and fixation of the axial position during manufacturing. For the sagging of the valve clack that may be caused during long-term use, it is also convenient to further adjust the lock to achieve zero leakage in long-term use.
Easy to replace the sealing ring
When the sealing ring needs to be replaced, there is no need to remove the disc, just open the valve fully, and then take out the key from the operating device, after the operating device is adjusted to the closed state, it still maintains the key connection with the main valve, and then continues in the opening direction Turn the hand wheel until the sealing ring is on the side of the valve body sealing surface to replace the sealing ring.
Related knowledge: the principle of butterfly valve structure
Related products: Electric flanged butterfly valve Pneumatic flanged 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

electric hard seal butterfly valve vs electric soft seal butterfly valve

June 18, 2021

The difference between electric hard seal butterfly valve and electric soft seal butterfly valve
With the rapid development of many industrial fields in our country, industrial automation has gradually replaced the manual operating system, especially the use of various automatic control valves. With its unique structural

wafer type butterfly valve, EPDM seat (10)

characteristics, electric butterfly valves have become one of the most used valve types. First, the scope of application is also the most extensive. However, in different working conditions, it is particularly important to choose different electric butterfly valves, not to waste costs, and to save resources. From the valve sealing structure, electric butterfly valves can be divided into two categories: soft seal and hard seal. What is the difference between them? Which one has more advantages? How should we distinguish between them?

The difference between the electric hard-sealed butterfly valve and the electric soft-sealed butterfly valve is mainly reflected in the performance and structure. The two seals can complement each other. Both have advantages and disadvantages. The advantage of one side may be the disadvantage of the other. When choosing, you should analyze your own needs, working conditions, etc., and choose the right product.
The main differences are as follows:
1. From the structure: the electric soft sealing butterfly valve is mostly in the middle line structure, and the sealing material is generally fluorine plastic, rubber, resin, etc., which has good corrosion resistance and sealing. Choose different parts and materials, which can be suitable for use. In a variety of media. Electric hard-sealed butterfly valves are mostly single-eccentric, double-eccentric and triple-eccentric butterfly valves. The seals are mostly stainless steel + cemented carbide. Among them, the three-eccentric butterfly valve has no friction transmission between the sealing surfaces, and has the characteristics of high temperature resistance, wear resistance, and good mechanical properties.

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

2. Temperature resistance: soft seal is used in normal temperature environment, hard seal can be used in low temperature, normal temperature, high temperature and other environments;
3. In terms of pressure: soft seal low pressure-normal pressure, hard seal can also be used in working conditions such as medium and high pressure;
4. Sealing performance: The soft sealing butterfly valve has better sealing performance and can reach zero leakage. The disadvantage is that it is easy to age, wear, and has a short service life. The hard-sealed butterfly valve can maintain good operation under high pressure and high temperature, is relatively resistant to wear, has good mechanical properties, and has a long service life, but the sealing performance is poor!
When the electric butterfly valve is opened and closed, it not only saves effort, but also has low flow resistance. It is convenient and quick to operate, light in weight, small in size, and has a relatively simple structure. Customers can choose a soft-seal or hard-seal butterfly valve reasonably according to economic conditions, the conditions of the medium used, and the on-site environment.

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

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