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bellows globe valve vs ordinary globe valve

June 29, 2021

The difference and comparison between bellows globe valve and ordinary globe valve
The bellows globe valve is also called the bellows seal globe valve. Through automatic seam welding, a metal barrier is formed between the fluid medium and the atmosphere to ensure the design of zero leakage of the valve stem. Compared with traditional globe valves, it has the following advantages:

Globe valve (9)

1. The bellows globe valve has a long service life, reduces the number of maintenance and lowers operating costs. The sturdy and durable bellows seal design ensures zero leakage of the valve stem and provides maintenance-free conditions.
2. The valve opening and closing torque is small, reducing labor intensity, and can drive any form of driving device, which is convenient for remote control.
3. The appearance is beautiful, the valve channel has a smooth streamline, and the flow resistance coefficient of the valve is reduced. It is a high-quality energy-saving product.
4. The outer seal of the valve adopts bellows seal and graphite, stainless steel gasket seal, the seal is reliable, and the sealing packing does not need to be replaced for long-term use. In industrial use, the leakage caused by the stop valve: high temperature, highly toxic, flammable and explosive, radiant medium, etc., not only pollute the environment, but also often cause significant personal and property losses. However, this type of valve is much safer and more stable, and strictly adopts foreign advanced standards in design and manufacturing.

Advantages and application of bellows globe valve The bellows globe valve has no leakage, and it is safer to be used in high-risk media. Ordinary globe valve is sealed with packing, the valve stem and packing will slide, and it is easy to leak at low temperature (spool).
The bellows cut-off valve uses a closed bellows that can be stretched and compressed to replace the packing seal, which can effectively prevent external leakage caused by packing loss. It is generally used for the transmission of highly permeable media, such as valves on hydrogen systems, as long as the bellows is not damaged, there is generally no leakage; while the general shut-off valve is sealed with packing, which is prone to leakage.
The opening or closing stroke of the valve stem of this kind of valve is relatively short, and it has a very reliable cut-off function. Also, because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for flow adjustment. Therefore, this type of valve is very suitable for use as a shut-off or adjustment and throttling.

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

O type |V type ball valve structure principle

June 28, 2021

Ball valve structure diagram, O-type ball valve structure principle, V-type ball valve structure principle
Ball valve structure:
Ball valves have many structures, but they are basically the same. They are all round cores with opening and closing parts. They are mainly composed of valve seats, balls, sealing rings, valve stems and other driving devices, which can be realized by rotating the valve stem by 90 degrees. The opening and closing of the valve is used in the pipeline to shut off, distribute, adjust the flow rate and change the flow direction of the medium. The valve seat uses different valve seat sealing forms according to different working conditions. The valve body structure has one-piece type, two-stage type and three-stage type.

ball valve (3)

O-type ball valve structure:
The O-shaped ball valve has a ball with a middle through hole installed inside the valve body. A through hole with the same diameter as the pipe diameter is opened on the ball. The ball can rotate in the sealing seat, and there is a ring-shaped elasticity on both sides of the pipeline direction. Body to achieve sealing. By rotating the ball 90°, the direction of the through hole can be changed, thereby realizing the opening and closing of the ball valve.
O-type ball valve core (ball) is spherical. From the structural point of view, the ball seat is embedded on the side seat of the valve body when sealing. Relatively moving parts are made of self-lubricating materials with a very small friction coefficient, so the operating torque is small. In addition, the long-term sealing of the sealing grease makes the operation more flexible. It is generally used for two-position adjustment, and the flow characteristic is quick opening.

Principle of O type ball valve:
When the O-type ball valve is fully opened, the two sides are unobstructed valves, forming a straight pipe channel, two-way sealing, with the best “self-cleaning” performance, and suitable for two-position cutting occasions with particularly dirty and fiber-containing media. The ball core always creates friction with the valve during the opening and closing of the valve. At the same time, the seal between the valve core and the valve seat is achieved by the pre-tightening force of the valve seat pressing the ball core, but due to the soft sealing of the valve seat. Excellent mechanical and physical properties make it particularly tight.
V-shaped ball valve structure:
The V-shaped ball valve core has a V-shaped structure. The valve core is a 1/4 spherical shell with a V-shaped gap. It has a large flow capacity, a large adjustable range, a shear force, and a tight closing. It is especially suitable for fluids. Working conditions where the substance is fibrous. Generally, V-type ball valves are single-sealed ball valves. Not suitable for bidirectional use.
The edge of the valve core is V-shaped, and there is a V-shaped opening on the sphere. With the rotation of the ball, the change in the opening area of the middle can be used to adjust the flow, and the impurities in the fluid can be cut off and closed. It is suitable for pulp, Control of mortar and viscous fluid.

Principle of V-type ball valve:
V-shaped edge cuts off impurities. During the rotation of the ball, the V-shaped knife edge of the ball is tangent to the valve seat, thereby cutting off the fiber and solid matter in the fluid. However, the general ball valve does not have this function, so it is easy to cause the fiber impurities to get stuck when closed, which will cause maintenance and repair. Maintenance brings great inconvenience. The valve core of the V-shaped ball valve will not be jammed by the fiber. In addition, due to the use of flange connection, it is easy to disassemble and assemble, no special tools are needed, and maintenance is simple and easy. When the valve is closed. There is a wedge-shaped scissors effect between the V-shaped notch and the valve seat, which not only has the function of self-cleaning but also prevents the ball from jamming. The valve body, bonnet and valve seat adopt a metal point-to-point structure, and a smaller friction coefficient is used. The stem spring, therefore, has a small operating torque and is very stable.

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 ball valve model preparation/code name designation method

June 24, 2021

Electric ball valve model preparation/code name designation method in China.
As an important equipment in the industrial automation control system, the electric ball valve has been used more and more in recent years due to its simple structure and convenient operation. It can not only be used to cut off or connect the medium in the pipeline, but also can be used for fluid Regulation and control! But because of the different working conditions of the pipeline, the electric ball valve models used are all different! The user should have a detailed understanding and cognition of the method of preparing the electric ball valve model!

Pneumatic electric high platform ball valve

This electric ball valve model editing method includes the addition of additional conditions for the ball valve, the selection of the drive mode, the different connection form, the change of the structure form, the type of sealing material, the level of the valve pressure and the valve body material, etc.!
Electric ball valve model representation method:
Ball valve additional code:
V means the spool has a V-shaped structure, D means low temperature, B means heat preservation, P means eccentric structure, U, S and DY mostly mean top-mounted type;
Ball valve name code: Q means ball valve; Ball valve drive code: 2 means electro-hydraulic, 3 means turbine, 6 means pneumatic, 7 means hydraulic, 9 means electric, manual without code;
Code of connection method: 1 means internal thread, 4 means flange type, 6 means welding, 7 means wafer type;
Structure type code:
Floating type: 1 means straight flow channel, 2 means Y-type tee, 4 means L-type tee, 5 means T-type tee;
Fixed: 0 means hemispherical straight through, 6 means four-way flow channel, 7 means straight flow to, 8 means L-type tee, 9 means Y-type tee;
Sealing material code: B babbitt alloy, F fluorine rubber, F46 lining fluorine, H stainless steel, J rubber lining, M Monel alloy, N nylon plastic, Monel P, Y cemented carbide, W valve body directly processed;
Pressure rating code: 16 means the pressure is 16 kg (1.6Mpa) and the maximum can reach 64Mpa; 150LB means the American standard pound pressure, and the maximum pressure rating can reach 2500LB (150LB=1.6MPA/300LB=2.5-4.0mpa/400LB=6.4 mpa/600LB=10mpa); 5K means daily pressure, the maximum pressure is 63K;
Valve body material code: A titanium and titanium alloy, C carbon steel, I chromium molybdenum steel, P18-8 series stainless steel, RMo2Ti series stainless steel, S plastic.
Editing instructions for electric ball valve model:
VQ947F-16P Stainless steel electric flange V-shaped ball valve
1. V: indicates that the spool has a V-shaped structure
2. Q: represents the ball valve;
3. 9: indicates that the transmission mode is electric;
4. 4: The connection method is flange connection;
5. 7: The structure is a fixed straight flow channel;
6. F: The sealing material is fluorine rubber;
7. 16: Indicates that the nominal pressure is 1.6MPa;
8. P: indicates that the valve body is made of stainless steel.

More details for valve model establishment, you can visit another article: https://www.tanghaivalve.com/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

The working principle of the ball valve (GIF)

June 23, 2021

Principle of Ball Valve (GIF), Principle of Ball Valve Working Principle

The opening and closing part of the ball valve is a sphere with a circular channel, which rotates around an axis perpendicular to the channel, and the sphere rotates with the valve stem to achieve the purpose of opening and closing the channel. The ball valve can be closed tightly with only a 90-degree rotation and a small torque. According to the requirements of the working conditions, different driving devices can be assembled to form ball valves with different control methods, such as electric ball valves, pneumatic ball valves, hydraulic ball valves, etc.
The working principle of the ball valve: When the ball valve rotates 90 degrees, the inlet and outlet should all show a spherical surface, thereby closing the valve and cutting off the flow of the medium.

ball valve working diagram-3D GIF animated presentation

When the ball valve rotates 90 degrees, all the ball ports should be present at the inlet and outlet, so as to open the flow, and there is basically no flow resistance.
The structure principle of the ball valve:
1. The ball valve is not restricted by the installation direction, and the flow direction of the medium can be arbitrary. The fluid resistance is small, and the full-bore ball valve basically has no flow resistance.
2. The ball valve has a simple structure, relatively small size, light weight and easy maintenance.
3. Close and reliable. It has two sealing surfaces, and the current sealing surface materials of ball valves are widely used in various plastics, which have good sealing performance and can achieve complete sealing. It has also been widely used in vacuum systems.
4. The ball valve is suitable for frequent operation, opening and closing quickly and lightly. It is easy to operate and open and close quickly. It only needs to rotate 90° from fully open to fully closed, which is convenient for remote control.

ball valve (4)

5. The maintenance is convenient, the structure of the ball valve is simple, the sealing ring is generally movable, and it is convenient to disassemble and replace.
6. The ball valve has good sealing performance. When fully open or fully closed, the sealing surface of the ball and the valve seat is isolated from the medium, and the medium will not cause erosion of the valve sealing surface when the medium passes.
7. It has a wide range of applications, with a diameter ranging from a few millimeters to a few meters, and can be applied from high vacuum to high pressure.
8. Since the ball valve has wiping properties during opening and closing, it can be used in media with suspended solid particles.
9. The ball valve has low fluid resistance, no vibration, and low noise.

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

Selection and application of eccentric butterfly valve

June 23, 2021

Selection and application of eccentric butterfly valve
The advantages of eccentric butterfly valves and other butterfly valves are very prominent, so they are widely used in all aspects of life and work to meet various requirements. Moreover, with the continuous development of eccentric sealing butterfly valve technology, the space for its use becomes more and more extensive. TH valve company can produce double eccentric butterfly valve and triple eccentric butterfly valves, with good quality and reasonable prices.

Double eccentric-wafer butterfly valve-D372F-150lbP-stainless steel (1)

Application of double eccentric sealing butterfly valve
The double eccentric sealing butterfly valve adopts an eccentric structure design. The main structure of the valve is composed of valve body, butterfly plate, valve seat, valve stem and transmission mechanism. The valve seat adopts a detachable structure and can be based on the physical and chemical properties of different media. Corresponding corrosion-resistant, light-resistant, and aging-resistant materials are selected, which can be widely used in fluid pipelines such as water supply and drainage, sewage, construction, air conditioning, petroleum, chemical, food, medicine, textile, papermaking, hydropower, shipbuilding, metallurgy, energy systems, etc. Used as a regulating and intercepting device. The double eccentric butterfly valve usually uses tetrafluoroethylene material as its sealing seat, and can also use metal sealing seat to expand its application in the high temperature field. However, the seal of the double eccentric butterfly valve with metal sealing seat is still a positional sealing structure, that is, the sealing surface of the butterfly plate and the seat is in line contact, so it cannot withstand high pressure, and it will inevitably lead to greater leakage when used in a high pressure system. Therefore, double eccentric butterfly valves with metal seal seats should be avoided as far as possible in high-pressure or tight shut-off systems.

Application of triple eccentric sealing butterfly valve
The triple eccentric butterfly valve, as the crystallization of the latest technology of valves, takes advantage of the advantages of various valves and avoids the shortcomings of various valves, and has attracted more and more

cryogenic triple offset butterfly valve 1

attention from users and designers. The maximum pressure level can reach 2500 pounds, the standard caliber can reach 48 inches, and the clamp, lug, flange, ring connection, butt welding, jacket, various structural lengths, etc. can be corresponded, due to the room for material selection Very large, high and low temperature, various acids, alkalis and other corrosive media can also respond freely. Especially in the aspect of large diameter, with its zero leakage advantage, it is constantly replacing the thick gate valve and ball valve in the shut-off valve. Similarly, with its excellent control function, it is also constantly replacing the bulky control valve. Shut-off valve. So far, triple eccentric sealing butterfly valves have been used in various important pipelines including China’s oil and gas exploration, offshore platforms, petroleum refining, petrochemicals, inorganic chemicals, energy power generation and other major industrial fields such as process control. In actual engineering, if the working pressure of the system is not less than 1.0 MPa or in important parts that need to be opened frequently, triple eccentric butterfly valves can be used.
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

full bore ball valve vs reduced bore ball valve

June 22, 2021

The difference and selection of full bore ball valve and reduced bore ball valve
Ball valve is currently the most widely used mechanical product in all valve markets. It is mainly composed of valve body, valve seat, ball, valve stem and transmission device. The ball core is driven to rotate through the actuator to achieve the function of switching or adjusting. . In the chemical industry, environmental protection, water treatment, urban construction, machinery, and food industries, it is widely used and very popular! there are Electric ball valve and Pneumatic ball valve, and other actuated ball valves.

Pneumatic electric high platform ball valve

There are many types of ball valves, which can be combined into various products with different functions through different structures, connection methods, pressure levels, drive forms, etc., but from the most basic point of view, ball valves have two types: full-diameter ball valves and reduced-diameter ball valves. The difference between major categories. Generally speaking, when the inner diameter of the valve ball is less than or equal to 85% of the inner diameter of the ball valve port, it is called a reduced-diameter ball valve, and when the inner diameter of the ball valve is greater than 95% of the inner diameter of the ball valve port, it is called a full-bore ball valve. So what is the difference between the two in the selection or application?
The definition of full bore ball valve and reduced bore ball valve:

fixed ball valve

1. The full-bore ball valve has equal-width flow channels, that is to say, the size of the orifices from inflow to outflow is the same, and its size cannot be less than the value specified by the standard, which is roughly equivalent to the nominal diameter of the specification, such as DN50 full-diameter The diameter of the ball valve flow path also needs to be about 50;
2. The inlet of the reduced diameter ball valve is wider than the diameter of the flow path, and the actual diameter of the flow path is about one specification smaller than this specification. For example, the diameter of the DN50 reduced diameter ball valve is about 38, which is roughly equivalent to the specification of DN40. One specification is reduced within DN250 and two specifications are reduced from 250-600. Above 600 depends on the actual situation.
Applicable medium for full bore ball valve and reduced bore ball valve:
1. The full-bore ball valve is generally used on pipelines for conveying viscous and slagging media. Because of its low fluid resistance, it can be said that there is basically no flow resistance, and it is convenient for regular wax scrapers to pass through.
2. Reduced diameter ball valve is suitable for conveying gas or pipelines with physical properties similar to water. Because its weight is about 30% lighter than a full-diameter ball valve, and its flow resistance is only 1/7 of that of a stop valve of the same diameter. about. It is helpful to reduce the pipeline load and reduce the cost.
Applicable process for full bore ball valve and reduced bore ball valve:
1. For pipelines that require regular pigging, no matter what kind of medium is transported, full-diameter ball valves must be used. The medium passing through the full-bore ball valve will not reduce the flow, and the flow resistance is small, which is an ideal product for pipeline control, especially for strict working conditions. Especially when the main line in the oil pipeline and gas pipeline needs to be buried underground, full-diameter welded ball valves must be used.
2. The reduced diameter ball valve is suitable for some working conditions such as low requirements and small convection resistance requirements. When the inner diameter of the valve is greater than 80% of the inner diameter of the pipe end, it has almost no effect on the pipeline fluid passing capacity. Many valves have a reduced diameter, which is generally controlled within 0.8. On the one hand, the reduced diameter reduces the flow capacity of the valve, that is, the Kv value of the valve, and increases the pressure drop at both ends of the valve, causing energy loss. That said, there is not much impact, and it may increase the erosion of the pipeline.
The advantages and disadvantages of full-bore ball valves and reduced-bore ball valves are compared:
1. Installation space: The reduced-diameter ball valve has a small volume, so its installation space requirements are smaller. Because its weight is about 30% lighter than a full-diameter ball valve, it is beneficial to reduce the pipeline load, reduce the transportation load and reduce the cost.
2. Cost: Reduced-diameter ball valves are one grade lower than full-diameter ball valves. Considering the cost performance, it is generally accepted internationally that adjacent pipe diameters use the same ball-diameter valve body. For example, dn32 and dn40, dn50 and dn63, dn90 and dn110, dn160 and dn200, dn250 and dn315 use the same sphere.
Note: Since the inner diameter of the reduced diameter ball valve is small, the torque on the valve stem is small, which is more suitable for prolonging the service life of the valve switch. Especially the low-torque design of large-diameter valves. However, the diameter cannot be reduced too much, otherwise the system resistance will increase. However, if the diameter is not reduced, the purchase cost will be increased, and the control characteristics of the valve will generally be reduced, which will make the adjustment effect worse. For example, if the regulating valve is always used at a small opening, the service life of the valve will be reduced.

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

Application of low temperature butterfly valve

June 22, 2021

Article title: Application of low temperature triple eccentric butterfly valve
With the rapid development of industrial technology, more stringent requirements have been put forward for valves, especially for butterfly valves used in low temperature media. In addition to meeting the performance of general valves, it is more important that butterfly valves seal under low temperature conditions. Reliability, flexibility of action and some other special requirements for cryogenic valves. Now combined with its structural characteristics, a brief introduction to the performance of the cryogenic butterfly valve is given. Remarks: The cryogenic butterfly valve we are talking about here specifically refers to the low temperature triple eccentric butterfly valve.

triple offset valve parts-after-cryogenic process

Requirements for sealing performance of low temperature triple eccentric butterfly valve:
There are two main reasons for the leakage of the low temperature triple eccentric butterfly valve, one is internal leakage; the other is external leakage.
1. Internal leakage of butterfly valve:
The main reason for the internal leakage of the valve is the deformation of the sealing pair in the low temperature state. When the temperature of the medium drops to a phase change of the material, the volume changes, which causes the sealing surface with high grinding accuracy to warp and deform, resulting in poor low-temperature sealing. We conducted a low temperature test on the DN250 valve. The medium was liquid nitrogen (-196 ℃) and the butterfly plate material was 1Cr18Ni9Ti (without low temperature treatment). It was found that the sealing surface warped and deformed up to about

cryogenic triple offset butterfly valve 1

0.12mm, which is the main cause of internal leakage. And if the plane seal of the butterfly valve is changed to a cone seal. The valve seat is an oblique cone ellipse sealing surface, which forms a sealing pair with a round elastic sealing ring embedded on the butterfly plate. The sealing ring can float radially in the butterfly plate groove. When the valve is closed, the elastic sealing ring first contacts the short axis of the elliptical sealing surface. As the valve stem rotates, the sealing ring is gradually pushed inward, forcing the elastic ring to contact the long axis of the oblique cone surface, and finally the elastic sealing ring All contact with the oval sealing surface. Its sealing is achieved by the deformation of the elastic ring. Therefore, when the valve body or butterfly plate is deformed at low temperature, it will be absorbed and compensated by the elastic sealing ring, and leakage and jamming will not occur. When the valve is opened, this elastic deformation disappears immediately, and there is basically no relative friction during the opening and closing process, so the service life is long.
2. Leakage of butterfly valve:
One is that when the valve and the pipeline are connected by flanges, leakage occurs due to the unsynchronized contraction and relaxation of the connecting gasket, connecting bolts, and connecting materials at low temperatures. Therefore, we changed the connection between the valve body and the pipeline from a flange connection to a welded structure to avoid low temperature leakage. The second is leakage at the valve stem and packing. Generally, most valve packing adopts F4 because of its good self-sliding performance, low friction coefficient (friction coefficient for steel f=0.05 ~ 0.1), and unique chemical stability, so it is widely used. However, F4 also has shortcomings. First, the tendency of cold flow is large; second, the linear expansion coefficient is large, and the cold shrinkage at low temperature causes leakage, which causes a large amount of ice at the valve stem, so that the valve fails to open. The low-temperature triple-eccentric butterfly valve developed for this purpose adopts a self-shrinking sealing structure, that is, taking advantage of the large expansion coefficient of F4, and achieves the purpose of sealing at room temperature and low temperature through the reserved gap.
Design requirements for low temperature triple eccentric butterfly valve body and stem bushing:
1. The structure and shape of the cryogenic valve shell. The correct selection of materials is of great significance to the normal and reliable operation of the valve. Compared with the stop valve and gate valve, the structural characteristics of the butterfly valve not only avoid the irregular shape and uneven shell wall thickness, which can cause problems at low temperatures. Due to the small size of the butterfly valve, the shape of the valve body is basically symmetrical, so the heat capacity is small; the pre-cooling consumption is also small; the shape is regular and it is convenient to take measures to keep the valve cold. ,
2. Selection of stem bushing: Some low-temperature triple-eccentric butterfly valves are in operation, the rotating parts of the valve are sticky, and seizure occurs from time to time. The main reason is: unreasonable selection of matching materials, too small pre-cooling clearance, and processing Causes such as low accuracy. In the development of cryogenic valves, a series of measures have been taken to prevent the occurrence of the above phenomena. For the upper and lower bushings of the valve stem, SF-1 type composite bearings with low friction coefficient and self-lubricating properties are selected, which can be suitable for some special needs of cryogenic valves. The metal-sealed butterfly valve has the characteristics that some ordinary valves do not have, especially the small flow resistance, reliable sealing, rapid opening and closing, and long service life. The triple eccentric metal sealing butterfly valve is sealed by the deformation of the elastic ring, so it does not need to rely on the force of the medium, so it can be used for two-way sealing.
Related information: The difference of cryogenic valve and ordinary temperature valve; Cryogenic valve principle |standard |illustration |selection

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

Fire-proof and anti-static ball valve and ordinary ball valve

June 18, 2021

The difference and selection of fire-proof and anti-static ball valve and ordinary ball valve
The fire-proof and anti-static ball valve is a kind of pipeline that can be used for natural gas, artificial coal gas, liquefied gas, city gas and non-corrosive gas. It has anti-static and fire-proof devices, that is, it is installed between

fixed ball valve

the ball and the valve stem, the valve stem and the valve body. The conductive spring enables the static electricity generated in the opening process of the valve to be introduced into the underground through the set static electricity channel, so as to achieve the purpose of eliminating static electricity. Avoid static sparking and ignite flammable media to ensure system safety. The fire protection device, that is, the ball valve is designed with double seals. When the soft gasket melts due to high temperature, the valve core ball is again designed to form a right-angle hard seal with the soft seal behind, forming a sealing relationship again.
The fire-proof anti-static ball valve is compared with the conventional ordinary ball valve. It will be widely used in many industries, and its safety performance has been improved a lot. For occasions prone to fire, it can effectively prevent internal leakage. The realization of this function mainly depends on the ball valve. Sealing ring, this kind of sealing ring is a double-layer seal, a layer of soft seal and a layer of metal seal, when the soft seal layer is destroyed by combustion, the metal seal can further fill the air, play a key alternate sealing role, can be to a certain extent It prevents a large amount of media from leaking out and the spread of fire.

electric ball valve

When the fire-proof and anti-static ball valve is switched, there will be friction between the ball and the valve seat, and the static electricity generated by the friction will accumulate on the ball. This is not allowed for the ball valves used on the gas, fuel, and chemical pipelines. , It may cause pipeline explosion accidents. The anti-static structure of the ball valve is equipped with an electrostatic discharge device, which can extract the electrostatic charge gathered in the sphere in the first time, effectively ensuring the safe operation of the pipeline; generally, elastic components are usually used at home and abroad According to the standard, the connection between the ball and the valve body and the valve stem and the ball is below 12VDC, and the resistance value is below 10 ohms.
It should be noted that the fire and anti-static functions of ball valves are not omnipotent. They can only play an emergency role and give more time to solve accidents. In addition to the use of fire-resistant and anti-static ball valves in gas and oil pipelines, they also It should be equipped with certain fire-fighting measures such as explosion-proof and fire-prevention, and strictly abide by relevant national regulations.

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

High platform ball valve and ordinary ball valve

June 17, 2021

The difference and selection of high platform ball valve and ordinary ball valve
High platform ball valve, the so-called high platform means that the ball valve adopts the ISO5211 manufacturing standard. A square or round flange and the ball valve are cast into one piece, and the end of the platform is higher than the outer edges of the flanges at both ends, which is not only conducive to easy installation Pneumatic actuators, electric actuators and other actuators can greatly improve the stability between the valve and the actuator, and the appearance is more beautiful and refined. The high platform usually called york or bracket.

Pneumatic electric high platform ball valve

Electric high platform ball valve Pneumatic high platform ball valve
The high platform ball valve is an evolution of the conventional ordinary bracket ball valve. The difference between it and the ordinary ball valve is that it can be directly connected to the drive actuator without installing a connecting bracket, while the ordinary ball valve requires the bracket to be installed before the actuator can be installed. . In addition to avoiding additional bracket installation, because it is installed directly on the platform, this greatly improves the stability between the actuator and the ball valve.
The advantage of the high platform ball valve is that it can directly install pneumatic or electric actuators on its own platform, while ordinary ball valves require additional valve connections. This may occur due to loose brackets or excessive coupling gaps. As a result, the valve is affected in use, but the high platform ball valve will not have this problem. Its performance is very stable during operation.

Schematic diagram of high platform ball valve

In the selection of high-platform ball valves and ordinary ball valves, the internal structure of the high-platform ball valve is still the principle of opening and closing, which is consistent with the ordinary ball valve. In addition to the advantages described above, when the medium temperature is relatively high, it needs to be adopted The connection bracket is to protect the normal use of the actuator and prevent the heat transfer of the medium from causing the actuator to be unusable.

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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