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Resilient seated vs metal seated wafer butterfly valve

December 20, 2021

The soft-seal wafer butterfly valve contains two characteristics, one is that the sealing form is a soft seal, and the other is the connection method is a wafer. Wafer butterfly valves are divided into soft sealing butterfly valves and hard sealing butterfly valves. Soft seal means that one side of the butterfly valve sealing pair is made of metal

JIS 10K-wafer butterfly valve-backup seat (4)

material, and the other side is made of elastic non-metal material. The advantage of the soft sealing wafer butterfly valve is that it is made of non-metallic materials with certain strength, hardness and temperature resistance. It has good sealing performance, but its service life and temperature adaptability are relatively poor. In contrast, the hard seal wafer butterfly valve is made of metal, which can meet the process requirements of some corrosive materials. The hard seal has a long service life, but the sealing performance is relatively worse than that of the soft seal. The main differences between the soft-seal wafer butterfly valve and the hard-seal wafer butterfly valve are as follows:
1. The difference in structure: soft-sealed butterfly valves are mostly centerline. Hard seal butterfly valves are mostly single eccentric, double eccentric and triple eccentric butterfly valves.
2. Temperature resistance: soft-sealed butterfly valves are mostly used in normal temperature environments. Hard seal butterfly valve can be used in low temperature, normal temperature, high temperature and other environments.
3. Pressure: The soft seal wafer butterfly valve is only used for low pressure to normal pressure, and the hard seal can also be used for working conditions such as medium and high pressure, which is more resistant to high pressure.
4. Sealing performance: The soft sealing and triple eccentric hard sealing butterfly valves have better sealing

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

performance. The triple eccentric butterfly valve can maintain good sealing under high pressure and high temperature environment.
In addition to the difference in product characteristics between the soft-seal wafer butterfly valve and the hard-seal wafer butterfly valve, their performance is also different, and they are used in different working conditions to adjust. The soft sealing wafer butterfly valve is suitable for the two-way opening and closing and adjustment of ventilation and dust removal pipelines, water treatment, light industry, petroleum, chemical and other industries. Hard-seal wafer butterfly valves are mostly used in heating, gas supply, and gas, oil, acid and alkali environments.
With the widespread use of the soft-seal wafer butterfly valve, its features of convenient installation, convenient maintenance, and simple structure become more and more obvious. Products have also been continuously upgraded. For example, the electric soft-seal wafer butterfly valve, pneumatic soft-seal wafer butterfly valve, etc., which have been continuously developed in recent years, are used in more and more occasions, and gradually began to replace the more expensive electric power with some limited functions. Gate valves, globe valves, etc.

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

Video of center-lined butterfly valve:

Video of double eccentric butterfly valve:

Is a gasket needed for installation of the resilient seated wafer butterfly valve?

December 17, 2021

Before understanding the problem of adding gaskets to the soft-seal wafer butterfly valve, let’s take a look at the main working conditions of the soft-seal wafer butterfly valve. It can be applied to water supply and drainage, gas pipelines such as food, medicine, chemical industry, petroleum, electric power, textile papermaking, etc. It is used for regulating flow and intercepting medium. And has certain standards, as follows:

Wafer type butterfly valve with worm gear

Standards for soft-seal wafer butterfly valves:
Gauge manufacturing specification: GB/T 12238-2008
Construction length specification: GB/T 12221-2005
Connection flange specification: GB/T 9113
Pressure temperature rating: GB/T 12224-2005
Experimental inspection specification: GB/T 13927-2008
The soft-seal wafer butterfly valve is characterized by sensitive operation, labor-saving, and good sealing performance. So the reason for choosing the soft-seal wafer butterfly valve to a large extent is because of its good sealing performance. Then, in actual field application, we encountered a problem: Can the connecting surfaces on both sides of the soft-seal wafer butterfly valve function as a flange gasket? When installing the butterfly valve, is it necessary to add gaskets for sealing? With such a question, let’s first look at a live case.
A new batch of soft-seal wafer butterfly valves from a factory are used for acidic liquid pipelines. The soft-seal of the product is made very thick, and some of the soft-seal material is exposed to form a convex surface. May I ask if this kind of butterfly valve is installed? Also add gaskets for sealing? Through practice, we have seen that this situation can be added or not, but it is added for more insurance. Generally, new soft-sealed butterfly valves can be sealed without gaskets. If it is an old valve, it is necessary to consider the problem of aging. Soft-seal butterfly valves generally come with a gasket, which can not be installed, but it depends on the application of the soft-seal wafer butterfly valve. For example, in this case, if it is used in high temperature or corrosive liquid pipelines, in order to avoid personal injury, it is recommended to add high-pressure PTFE gaskets during flange connection, so that it can be safer and can be done once and for all. The purpose of adding gaskets is to protect the rubber-lined flange surface, because the replacement valve ring is more expensive than the replacement valve gasket. If the gasket is not added under bad working conditions, even if the flange does not leak, it is very likely that the valve will leak internally.
So in summary, whether the soft seal wafer butterfly valve needs to be gasketed depends on the chemical nature, temperature and pressure of the pipeline medium. Generally speaking, although the connecting surfaces on both sides of the soft seal wafer butterfly valve can play the role of flange gasket, it is recommended to add a gasket on both sides for safety. Because the butterfly valve will bump and bump a little during transportation and handling, it will produce an incomplete sealing surface, so it is recommended to add an extra gasket. Of course, there are other points of view that there is no need to add shims, and it is superfluous. Therefore, we can refer to a standard and then make a choice according to our specific working conditions, which can be based on the valve diameter, etc.: soft-seal wafer butterfly valves under 6 kg may not be added; 6-16 kg butterfly valves are recommended to add gaskets. Spacers below DN300 are 1.5mm; spacers above DN300 and below 1200 are 3.0mm. For more butterfly valve information, please contact Tanghai Valve’s online customer service.

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

Video of center-lined butterfly valve:

Troubleshoot reasons for pneumatic wafer butterfly valves

December 16, 2021

The pneumatic wafer butterfly valve has a beautiful appearance and is matched with a pneumatic actuator. The valve plate and the valve shaft can be connected without a pin, and the medium is completely isolated from the valve shaft and valve body, which is simple and easy to maintain. Pneumatic wafer butterfly valves are widely used in industrial automation systems in food, environmental protection, light industry, petroleum, papermaking, chemical, electric power and other industries. Pneumatic wafer butterfly valves are divided into soft seal and hard seal, and the two products also have their own different characteristics.

JIS 10K-wafer butterfly valve-backup seat (1)

The design features of the high-quality pneumatic wafer butterfly valve include: the valve body and end cover adopt dewaxing precision casting; the valve stem has an explosion-proof design; the standard air source interface can be directly connected to the solenoid valve; the cylinder inner wall anode hardening does not require secondary lubrication ; Switch position +/-5° stroke adjustment, easy to operate; 360°C any angle installation, etc. Its performance specifications are: nominal pressure: 1.0MPa-2.5MPa, nominal passage: DN32~DN600, applicable temperature: -20~+120 ℃. The hard seal will be higher. The soft-seal pneumatic wafer butterfly valve is used in normal temperature environment. The hard-sealed and soft-sealed pneumatic wafer butterfly valve can be used in low temperature, normal temperature, high temperature and other environments.
In use, we sometimes encounter the phenomenon that the pneumatic wafer butterfly valve does not work. Is it improper use or product quality? How do we troubleshoot the cause? Here is a reference. Pneumatic wafer butterfly valves are mainly composed of pneumatic actuators and butterfly valves. Pneumatic accessories are installed according to user requirements. Pneumatic accessories for on-off type pneumatic butterfly valves include solenoid valves and limit switches, adjustable type with positioners and filter decompression Device. Therefore, when the pneumatic wafer butterfly valve fails, it is necessary to investigate the cause one by one from each component.
The main points are as follows:
1. Pneumatic actuator:
(1) There is no air source and the air source is not opened (2) The air source pressure is insufficient (3) The cylinder piston is aging and fractured (4) The rack of the piston gear is worn (5) The single-acting actuator is rusted due to the long-term use of the spring;
2. Valve body:
(1) The valve stem is twisted or broken (2) The valve stem is rusted due to internal leakage of the medium (3) The medium has impurities and the valve plate and valve seat are stuck
3. Solenoid valve:
(1) If the terminal is loose or falling off, no electricity (2) The coil is burnt out (3) The solenoid valve is easy to get stuck when there are impurities or too little lubricating oil (4) Air leakage, the solenoid valve leaks and the air source pressure is insufficient;
4. Positioner:
(1) The air source is not turned on (2) In winter, the air source contains water and freezes causing the air duct and filter to be blocked (3) The regulator fails and the regulating mesh diaphragm is damaged;

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

Video of center-lined butterfly valve:

Advantages and Features of Center-lined Wafer Butterfly Valve

December 15, 2021

The centerline wafer butterfly valve is a kind of centerline butterfly valve, which has two characteristics of wafer connection and centerline sealing. Today, the advantages and characteristics of the centerline wafer butterfly valve are based on the flange butterfly valve. details as follows:

Wafer type butterfly valve with worm gear

Pressure Level
The centerline wafer butterfly valve generally does not have a high pressure, and cannot be made with a higher pressure level like the flange butterfly valve. The nominal pressure of flanged butterfly valves is higher than that of wafer butterfly valves.

Install
During installation, the centerline wafer butterfly valve is generally installed with a matching flange, and the flange butterfly valve does not need to be equipped separately. The valve bolt length of the wafer butterfly valve will be longer, so the construction accuracy is higher. Because if the flanges on both sides are misaligned, the bolts will be subjected to greater shearing force, and the valve is prone to leakage.

Repair and maintenance
The centerline wafer butterfly valve generally cannot be used in the end of the pipeline and the downstream occasions that need to be disassembled, because when the downstream flange is removed, the wafer valve will fall. In this case, another short section must be made for disassembly. The flanged butterfly valve does not have the above problems, but the cost will be relatively high. The wafer butterfly valve has no flanges at both ends of the valve body, only a few guide bolt holes, and the valve is connected with the flange at the end by a set of bolts/nuts. In contrast, disassembly is more convenient, and the valve cost is lower, but the disadvantage is that one sealing surface has a problem, and both sealing surfaces have to be disassembled.
Due to installation reasons, if you encounter a situation where you need to install a blind plate, this situation is actually quite often encountered. In this situation, the midline wafer butterfly valve can only be installed with transitional pipe sections or replaced with other types of valves. It is impossible to disassemble the blind plate on the center line of the clamp butterfly valve. It is necessary to add a pair of flanges to the straight pipe section behind the valve after stopping, and at the same time add the figure 8 blind plate to avoid insufficient position when the blind plate is added in the future.

Better tightness
The centerline wafer butterfly valve has a poorer sealing effect than the flange butterfly valve. For example, the transportation of slurry media causes blockage. The advantage of the center line to clamp butterfly valve is that it is easy to disassemble and assemble, but it will leak if it is not installed well. Flanged butterfly valves are expensive. The valve is equipped with flanges. The flanges on both ends of the valve are connected to the pipe flanges with bolts. The sealing performance is better than that of the clamp butterfly valve. Flange butterfly valves are easier to make eccentricity, and multiple eccentricities can achieve excellent sealing performance, but it is not easy to achieve a wafer butterfly valve. If the centerline wafer butterfly valve is a soft sealing butterfly valve, the rubber liner damage cannot be repaired on site, but the flange type can be repaired.

In summary, the centerline wafer butterfly valve has low cost and strong adaptability to installation space. The disadvantage is that the sealing performance is not as good as the eccentric butterfly valve and the flange butterfly valve, and the disassembly and maintenance will be slightly more troublesome than the flange butterfly valve. Under the condition that the medium pressure is not particularly high and the working conditions are ordinary, the centerline wafer butterfly valve is still a good choice from the comprehensive examination of cost, sealing performance, installation and maintenance.

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

Video of center-lined butterfly valve:

Precautions for installation of pinless wafer butterfly valve

December 14, 2021

The pinless wafer butterfly valve contains two connection methods, one is pinless and the other is wafer. A pinless butterfly valve is a pinless butterfly valve that does not use a pin to penetrate the connection between the valve plate and the valve stem. For comparison of pin butterfly valves and pinless butterfly valves, please refer to valve knowledge. The wafer butterfly valve is connected between two pipe flanges with stud bolts, without flanges.

JIS 10K-wafer butterfly valve-backup seat (4)

Commonly used pinless butterfly valves include wafer type butterfly valves and flange type butterfly valves, so flange type butterfly valves are often compared with wafer type butterfly valves. The biggest difference between the two is the connection method during installation. Now let’s take a look at what to pay attention to when installing the pinless wafer butterfly valve.
1. During installation, the valve disc should be stopped in the closed position.
2. The opening position should be determined according to the rotation angle of the butterfly plate.
3. For the butterfly valve with bypass valve, the bypass valve should be opened before opening.
4. The installation should be carried out according to the installation instructions of the manufacturer, and the heavy-weight butterfly valve should be installed with a firm foundation.
5. The butterfly plate of the pinless wafer 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 0-90°. When the rotation reaches 90°, the valve is fully open.
6. If the butterfly valve is required to be used as a flow control, the main thing is to select the size and type of the valve correctly. The structure principle of the butterfly valve is especially suitable for making large-diameter valves. Butterfly valves are not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also used in cooling water systems of thermal power stations.
The price of the pinless wafer butterfly valve is roughly 2/3 of that of the pinless flange butterfly valve, which is relatively cheap, but the sealing performance is not as good as that of the flange butterfly valve. When choosing imported valves, use wafer butterfly valves as much as possible because they are cheap and light in weight. One of its limitations is that there are no flanges at both ends of the valve body, and there are only a few guide bolt holes. The valve is connected to the end flange with a set of bolts/nuts. Compared with the flanged butterfly valve, it is much more convenient to disassemble, and the valve cost is lower, but the disadvantage is that one sealing surface has a problem, and both sealing surfaces have to be disassembled. The paired flanges of the clip-on type are butt welded and cannot be installed by socket welding.
The pinless wafer butterfly valve also has its own advantages, that is, it saves space, and try to use wafer butterfly valves when the piping position is tight. The biggest difference between the pinless wafer butterfly valve and the flangeless butterfly valve is that the wafer butterfly valve saves a pair of flanges, so the cost is relatively cheap, but it is not conducive to the disassembly and assembly of maintenance, etc., where permitted, priority Choose a wafer butterfly valve. Wafer butterfly valves are generally used in industrial pipelines with relatively low pressure and relatively safe transport media.

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
Video of center-lined butterfly valve:

Is the EPDM butterfly valve suitable for water medium?

December 13, 2021

EPDM rubber butterfly valve fully meets the water working conditions and is a kind of soft sealing butterfly valve. It has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical properties, oil-filling properties and fluidity at room temperature. It can be used in ozone-resistant, weather-resistant, and ultraviolet-resistant applications, but based on its own structural characteristics, EPDM butterfly valves have poor flame retardancy, oil resistance and adhesion. Now let’s take a look at the specific performance of EPDM butterfly valve:

wafer type butterfly valve, EPDM seat (10)

1. Low density and high filling:
The seat material of EPDM butterfly valve is a kind of rubber with lower density. A large amount of oil and filler can be added, so it can reduce the cost of rubber products, make up for the high price of EPDM rubber, and the physical and mechanical properties of the valve seat sealing surface are not greatly reduced after high filling.
2. Aging resistance:
EPDM butterfly valves have a common feature of rubber that is not resistant to high temperatures. It can be used for a long time at 120 ℃, and can be used briefly or intermittently at 150 to 200 ℃. However, manufacturers now also try to add suitable antioxidants to increase the temperature of the valve, and the EPDM butterfly valve cross-linked with peroxide can be used under more severe conditions.
3. Corrosion resistance:
EPDM butterfly valves have good resistance to various polar chemicals, such as alcohols, acids, alkalis, oxidants, refrigerants, detergents, animal and vegetable oils, ketones and greases. But it has poor stability in gasoline, benzene, etc. and mineral oil. Therefore, it is not suitable for oil, and its performance will decrease under the long-term action of concentrated acid.
4. Water vapor resistance:
EPDM butterfly valve has excellent performance in water vapor resistance. It is much higher than the performance of fluorine rubber, silicon rubber, fluorine silicon rubber, butyl rubber, nitrile rubber, and natural rubber under the same conditions.
5. Superheated water resistance:
The superheated water EPDM butterfly valve is also no problem, the mechanical properties change very little, and the volume expansion rate is low, but it is closely related to the vulcanization system used.
6. Electrical performance:
Compared with styrene butadiene rubber, polyethylene and cross-linked polyethylene, the electrical performance of EPDM butterfly valve is very close or even better, and it has good electrical insulation and corona resistance.
7. Flexibility:
In terms of elasticity, EPDM butterfly valves are second only to natural rubber and butadiene rubber, and can still be maintained at low temperatures.
8. Adhesion:
Due to the lack of active groups in the molecular structure of EPDM, the cohesive energy is low, and the rubber is easy to bloom, and its self-adhesiveness and mutual adhesion are very poor.

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

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

How to choose the material of flanged gate valve seat

December 10, 2021

The sealing surface of flanged gate valve is an important working surface for the valve to block the medium and control the fluid. The quality of the sealing surface determines whether the valve is guaranteed to have no internal leakage, impermeability and other direct influence factors, which can be said to determine the service life of the valve. If the sealing surface is damaged, the valve will not work properly. Among them, the material selection of the sealing surface is a very important factor, and it is very important to guarantee the quality of the sealing surface. Therefore, the following factors should be considered when selecting the valve sealing surface material:

AWWA C509-C515-resilient seated gate valve-DN600-150lb (2)

1. Corrosion resistance
Whether the medium is pure water or other, it will cause certain corrosion to the flanged gate valve. The surface of the sealing surface will inevitably be damaged under the action of the high-speed passage of the medium. Delaying this process is our primary consideration when selecting sealing surface materials. Once the surface of the sealing surface is damaged, the sealing performance of the valve cannot be guaranteed, and the medium will easily leak from the damaged part of the sealing surface. Therefore, the sealing surface material must be corrosion resistant. The corrosion resistance of a material mainly depends on the chemical stability of the material. But secondly, we must consider the medium conditions to see if it matches the sealing material.
2. Friction resistance
Because the medium and the sealing surface move relative to each other, and it is a high-speed process, damage to the material due to friction is inevitable. Such damage will eventually inevitably cause damage to the sealing surface. Therefore, the sealing surface material must have good friction resistance, especially for flanged gate valves. The wear resistance of the sealing material is often determined by the internal properties of the material. At the same time, pay attention to the valve installation location to meet the needs.
3. Erosion resistance
The image of the erosion phenomenon is a process in which the sealing surface is destroyed when the medium flows through the sealing surface at a high speed. This kind of damage is more obvious in the throttle valve used in high temperature and high pressure steam medium, because it needs to be opened and closed frequently, which has a great impact on the damage of sealing. Therefore, erosion resistance is also one of the important requirements of the sealing surface material.
4. The sealing surface of flanged gate valves should have a certain degree of hardness, and the hardness will drop greatly under the specified working temperature.
5. The linear expansion coefficient of the sealing surface of the gate valve and the body material should be similar, which is more important for the structure of the inlaid sealing ring, so as to avoid excessive stress and loosening at high temperatures.
6. When used under high temperature conditions, it must have sufficient anti-oxidation, thermal fatigue resistance and thermal cycling.
When faced with real working conditions, it is difficult to find a sealing surface material that fully meets the above requirements. It is appropriate to match and choose according to different valve types and uses. There are several key points such as: often need to open and close, or in high-speed medium, the sealing material of flanged gate valve used here should be specially marked with erosion resistance requirements, and if it contains solid impurities, the hardness should be selected The higher the sealing surface material, the better the durability.

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

Video of resilient seated gate valve: https://youtu.be/AI-LT1dy2sU

Evolution of the Sealing Surface of the Triple Eccentric Butterfly Valve

December 9, 2021

The triple eccentric butterfly valve is one of the butterfly valves. Its unique sealing form and sealing structure are continuously improved and upgraded through the product to obtain a better sealing effect. There have been great reforms in high temperature and corrosion resistance. Let’s take a look at its product upgrade process.

triple offset butterfly valve-double flange- (5)

The butterfly valve’s single eccentric soft-seal butterfly valve is the first to be favored by the market. Because of the design of the soft seal, the product has a good sealing effect. Single eccentricity means that the sealing section of the valve seat is eccentric relative to the center of rotation of the valve stem, so that the sealing surface of the butterfly plate gradually separates from the sealing surface of the valve seat during the opening process. When 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, so that the relative mechanical wear and extrusion between the two sealing surfaces of the butterfly valve is greatly reduced during the opening process, and the sealing performance of the butterfly valve is improved. This design mainly relies on the elastic deformation of the squeezing between the butterfly plate and the valve seat to ensure the sealing of the butterfly valve.
In order to meet the needs of the site, to achieve the effect that the sealing surface of the butterfly plate is separated from the sealing surface of the valve seat faster than the single eccentric structure, the double eccentric sealing butterfly valve is upgraded on the basis of the single eccentric butterfly valve. The lines are relatively offset, so that the butterfly valve forms a cam effect during the opening process. When the butterfly plate rotates to 8°~12°, the two sealing surfaces can be completely separated. The biggest benefit of this structural design is to further reduce the mechanical wear and extrusion deformation between the two sealing surfaces, which improves the sealing performance of the butterfly valve and increases the lifespan.
The triple eccentric sealing butterfly valve is once again upgraded on the basis of the double eccentric butterfly valve. The center line of the seat sealing surface and the valve center line form an angular eccentricity, and a third eccentricity appears. In this way, during the opening process, the sealing surface of the butterfly plate can be separated from the sealing surface of the valve seat immediately, and will contact and compress the sealing surface of the valve seat at the moment of closing. This unique eccentric design makes full use of the benefits of the cam, so that the mechanical friction and scratches between the two sealing surfaces of the butterfly valve seal pair can be completely eliminated when opening and closing, so that the possibility of wear and leakage is eliminated. The product changes the extrusion seal into a torque seal. By adjusting the external driving torque, the adjustment of the seal specific pressure is realized, so that the sealing performance and service life of the triple eccentric structure sealing butterfly valve are greatly improved. At the same time, while ensuring a tight seal, it also improves the characteristics of the sealing sub-materials of the single-eccentric soft-seal butterfly valve and the double-eccentric soft-seal butterfly valve that cannot withstand high temperature and wear.
Now, the triple eccentric sealing butterfly valve is widely used as the best device to cut off or adjust the flow of the medium pipeline in the urban construction, petrochemical, metallurgy, electric power and other industries. Its structure itself is the most ideal opening and closing part in pipelines, and it is the development direction of today’s pipeline opening and closing parts. If you need butterfly valve products, look for Tanghai Valve. 24 years of experience in butterfly valve production is more assured.

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
Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0

Two-way triple eccentric butterfly valve

December 8, 2021

The two-way hard-sealed butterfly valve is a valve product that has been developed rapidly in recent years. From the earliest centerline butterfly valve to the later triple eccentric sealing butterfly valve to the current triple eccentric two-way sealing structure, the hard sealing butterfly valve has greatly reformed and improved its own sealing performance. In the course of this evolution and development, leading valve manufacturers have paid tremendous hard work and efforts.

cryogenic triple offset butterfly valve 1

Let’s first take a look at the sealing characteristics of the two-way hard-sealed butterfly valve. Its sealing material is forged with metal or materials with strong hardness. It has strong durability and longer service life than ordinary valve products. However, because of the material characteristics of the sealing surface, the sealing performance is worse than that of ordinary butterfly valves. Make it completely sealed. But now, with the improvement of technology, there have been the emergence of multi-layer hard sealing butterfly valves, which can achieve zero leakage and have the dual advantages of soft and hard sealing.
The seat sealing surface of the two-way hard sealing butterfly valve adopts alloy material butt welding form, high temperature resistance, easy to operate, and the opening and closing torque is transmitted to the valve stem without friction, which greatly improves the sealing performance of the sealed butterfly valve and prolongs its service life. Its main technical feature is the advantages of sealing two-way. This structure effectively compensates for the pressure of the medium, and can achieve zero-leakage sealing performance regardless of whether it is at low temperature or high temperature.
Science and technology are developing, and society is also progressing. In the past ten years of development, the two-way hard seal butterfly valve has made great progress in product development, performance, quality, reliability, and service. The market prospects are optimistic. In the future, valve manufacturers will also make greater efforts to continuously innovate and formulate development paths in terms of electricity, water, and materials. Speed up the elimination of low-efficiency and high-energy-consuming butterfly valve products, adjust the industrial structure, and promote the development and promotion of new technologies and products. At present, some long-established manufacturers already have their own multi-system butterfly valve products. If you want to purchase two-way hard-sealed butterfly valves, Tanghai Valve is your first choice.

Compared with ordinary butterfly valves, the two-way hard-to-hard seal butterfly valve has the biggest difference in that it does not require the installation direction, that is, the direction of its input and output is uncertain. Ordinary butterfly valves are one-way and have restrictions on the installation direction. In addition to this, there is another point to pay attention to when installing the two-way hard-to-hard seal butterfly valve, that is, it cannot be installed and used in places with too much pressure.
Why can’t the two-way hard-to-hard sealing butterfly valve be used in places with too much pressure? Now let’s take a look at the reasons:
1. Because the valve plate is in a normally open state, the sealing ring fixed on the valve plate is multi-layered, that is, multi-layer soft and hard stacked sealing ring. In the normally open state, the medium will flush its sealing surface positively. If the pressure is too high, the soft sealing tape in the metal sheet sandwich will be easily washed away and cause leakage.
2. At the same time, because the overall structure of the valve plate of the two-way hard-to-hard seal butterfly valve is generally thicker, the flow resistance is also relatively large. If it is installed in a place with high pressure, the flow resistance and friction can be imagined, and the damage to the sealing surface will be great.
3. Because this product is a two-way seal, the product seal is mainly to press the valve plate against the valve seat through the torque of the transmission device. The greater the pressure, the tighter the seal, but it should be in a positive flow state at this time. But if the medium in the flow channel flows backwards, if it is installed in a pipeline position with too much pressure, it is easy to cause the positive pressure of the seal between the valve plate and the valve seat to be less than the medium pressure, and leakage will occur.
The two-way hard-to-hard sealing butterfly valve has many advantages, including: it is not hindered by forward pressure and reverse pressure, and can be reliably shut off; the two sealing surface materials of the sealing pair can choose different functional materials according to different hardness; there is automatic The centering function can automatically overtravel to compensate for wear. In addition, a series of advantages such as small size, light weight, convenient transportation, installation, maintenance and repair, and reliable operation make the two-way hard-to-hard seal butterfly valve more and more popular in the market. If you have relevant needs, please consult Tanghai Valve and choose your suitable valve product.

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

Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0

Purchasing precautions for handle butterfly valves

December 7, 2021

When purchasing handle butterfly valves, it is not enough to only know the product specifications, categories and working pressure requirements, and it is impossible to achieve a good balance. Because different handle butterfly valve manufacturers have their own corporate standards and product personality, and some non-standard

JIS 10K-wafer butterfly valve-backup seat (4)

production to meet different customer requirements, it is unscientific to purchase valves based on rigid requirements such as specifications. So what should we refer to? There are mainly several aspects, including working pressure, caliber, what medium to pass, and what to use, etc. When purchasing valves, detailed technical parameters must be listed and a consensus must be reached with the valve manufacturer. Below we introduce in detail:
1. Working conditions
Valve specifications and types should be combined with the requirements of pipeline planning documents, that is, working conditions. The model of the valve should indicate the national standard number it is based on. The working pressure of the valve, the working pressure of the pipeline, and the working pressure that the valve can take over should be greater than the actual working pressure of the pipeline. Either side of the valve in the closed state should be able to take over 1.5 times the valve working pressure without leakage. When the handle butterfly valve is in the open state, the valve body needs to be able to take over twice the pressure of the valve. The valve manufacturing standard should be clearly based on the national standard number.
2. Valve standard quality
The material of the valve body should be mainly carbon steel and stainless steel. Stem material, stainless steel stem that is not easy to rust is more commonly used, and the nut material is mostly brass or bronze. The material of the sealing surface can be divided into metal seal and soft seal. The valve seat and valve plate are made of metal material, which is a hard seal, including stainless steel, ductile iron, etc. If one side between the valve seat and the valve plate is made of elastic material such as rubber, tetrafluoroethylene, etc., it is a soft sealing butterfly valve. When purchasing soft-seal handle butterfly valves, the physical, chemical and hygienic testing data of the valve plate lining material should be clear. For the sanitary, anti-aging performance, and wear resistance of the handle butterfly valve, you must also understand the manufacturer.
The above is the best technical knowledge to know when purchasing handle butterfly valves. At present, many valve factory products in our country still have the shortcomings of internal leakage, low appearance quality, short life, inflexible operation, and unreliable valve electric and pneumatic devices. Some high temperature, high pressure and valves required on key devices still rely on imports. Therefore, in order to make a breakthrough in the industry, Tanghai Valve has a clear focus on the concept of boutique: whether it is the exhibits at the exhibition or the parts seen by the visiting enterprises, the appearance of Tanghai Valve is neat and delicate, and the parts protection is in place. Small parts Use plastic protective covers, wooden seats and leather pads for large parts. These details are countless, all in order to establish a better brand image and increase the trust of new customers in the product. If you want to purchase handle butterfly valves, please come to Tanghai to visit and purchase, more professional and more assured.

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

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

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