manufacturer Archives

What is a fluorine-lined valve? How to extend the service life of it?

January 4, 2022

Fluorine-lined valves are made by using PTFE resin (or profile processed) to be molded (or inlaid) on the inner wall of the steel or iron valve pressure part or the outer surface of the valve inner part, and use its The unique performance of the anti-corrosive medium valve is made into various types of valves and pressure vessels.

Fluorine lined butterfly valve-PTFE-WAFER (10)

Among anti-corrosion materials, polytetrafluoroethylene has incomparable excellent performance. In addition to molten metal, elemental fluorine and aromatic hydrocarbons, it is used in various concentrations of hydrochloric acid, sulfuric acid, nitric acid, aqua regia, organic acids, strong oxidants, and concentrated , Alternate dilute acid, alternate alkali, and various organic agents are all reacting spontaneously. The inner wall of the valve is lined with polytetrafluoroethylene, which not only overcomes the shortcomings of low strength of polytetrafluoroethylene material, but also solves the corrosion resistance of the valve theme material. Poor performance and high cost. In addition to its excellent chemical stability, PTFE has good antifouling, anti-sticking properties, extremely low dynamic and static friction coefficients, and good anti-friction and wet performance. Use it as a valve opening and closing sealing pair, and it is necessary to reduce the sealing surface The friction force between the valve and the operating torque of the valve is reduced, and the service life of the product is increased. The scope of its application can also be extended to the food and pharmaceutical industries.

Fluorine-lined valves are also known as anti-corrosion valves. They are often exposed to harsh working conditions. They are not toxic and harmful chemicals, or are very corrosive. Various acids and alkalis or organic solvents. Improper use will cause major economic losses and serious problems. as a result of. Correct use and maintenance of the valve can prolong the service life of the fluorine-lined valve. What details can be done to effectively protect it?
1. Before use, carefully read the fluorine-lined valve instruction manual.
2. Use according to the pressure, temperature, and use medium specified on the nameplate or in the manual.
3. When using, prevent the fluorine-lined valve from generating excessive pipeline stress due to temperature changes, minimize temperature changes, and add U-shaped expansion joints before and after the valve.
4. It is forbidden to use levers to open and close the fluorine-lined valve. Pay attention to the opening and closing indication position and limit device of the fluorine-lined valve. After opening and closing are in place, do not forcefully close it to avoid premature damage to the fluorine plastic sealing surface.
5. For some media that are unstable and easy to decompose (such as the decomposition of some media will cause volume expansion and abnormal pressure increase in working conditions), which will cause valve damage or leakage, measures should be taken to eliminate or limit the factors that cause unstable media to decompose . When selecting the valve type, the fluorine-lined valve with automatic pressure relief device should be selected in consideration of the changes in working conditions that may be caused by the unstable and easy decomposition of the medium.
6. For fluorine-lined valves on pipelines with toxic, flammable, explosive, and highly corrosive media, it is strictly forbidden to replace the packing under pressure. Although the fluorine-lined valve is designed to have an upper sealing function, it is not recommended to replace the packing under pressure.
7. For pipelines with spontaneous flammable media, measures must be taken to ensure that the ambient temperature and working condition temperature do not exceed the spontaneous ignition point of the media to prevent the danger caused by sunlight or external fire.

Applicable medium: various concentrations of acid-base salts and certain organic solvents.
Features: It is the most ideal anti-corrosion material in the world at present, and it has been widely used in the lining of large-scale rotary forming equipment and pipe fittings.

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 PTFE butterfly valve:

Structure of Triple Eccentric Metal seated Butterfly Valve (Picture)

December 31, 2021

Butterfly valves can be divided into soft-sealed butterfly valves and metal seated butterfly valves according to the sealing form. This article mainly analyzes the structure of the triple eccentric metal seated butterfly valve. Metal hard seal butterfly valves are usually used in some high temperature and high pressure environments. They are mainly composed of valve body, butterfly plate, valve shaft, valve seat, butterfly plate sealing ring, shaft sleeve, self-lubricating bearing, driving device and so on.

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

The triple eccentric metal hard seal butterfly valve is a high-performance butterfly valve. It drives the rotation of the valve shaft through various driving devices, and the valve shaft drives the butterfly plate to rotate within the range of 0-90° in the valve body passage to achieve the valve opening and closing. The purpose is to realize the control of the medium flowing in the pipeline. Because of its super high performance, the triple eccentric metal hard seal butterfly valve can be widely used in the pipelines of generators, steam, hot and cold air, chemical smelting engineering, power generation, environmental protection, etc. The applicable media include various corrosive and non-corrosive fluid media. .

Structure diagram of triple eccentric metal seated butterfly valve
Insert “154-1 Picture”

Structural features of triple eccentric metal seated butterfly valve
①Unique and novel three-way eccentric design, frictionless transmission between sealing surfaces, greatly prolonged valve life.
②The elastic seal is produced by the torque, which improves the sealing performance of the valve.
③The wedge-shaped design allows the valve to be closed tighter and tighter, realizing automatic sealing, and the sealing surfaces directly compensate each other to achieve zero leakage.
④The drive mode of the valve can be selected according to the needs of customers, such as equipped with pneumatic and electric devices.
⑤ Only need to change the material of the parts, the valve can be applied to different media, and it can also be lining anti-corrosion (lining F46, GXPP, PO, etc.).
⑥The sealing ring is made of stainless steel, and it has the advantages of metal hard seal and elastic seal. It can achieve good sealing performance regardless of low temperature environment or high temperature working conditions.

If you want to know more about the triple eccentric metal seated butterfly valve, please pay more attention to the official website of “Tanghai Valve”. If you have any valve requirements in this area, you are also welcome to inquire.

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:

Application of Soft Seal Wafer Butterfly Valve in Sewage Treatment

December 28, 2021

The soft-seal wafer butterfly valve is now closely inseparable from various township sewage treatment plants. In the past agricultural villages, the sewage discharge facilities of farm households have not been transformed, resulting in the direct discharge of a large amount of domestic sewage, which seriously affected the lives of local villagers and

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

threatened the ecological environment of rivers and rivers. With President Xi’s idea that “green water and green mountains are golden mountains and silver mountains”, the overall management of the city’s urban domestic sewage and the strengthening of the city’s ecological civilization construction are highly valued. While the construction of the township sewage treatment plant is in full swing, it is the important role of the soft seal butterfly valve in the sewage treatment.
Sewage treatment valves are generally soft-sealed butterfly valves, seat-sealed elastic gate valves, etc. If the sewage is acidic, it may be necessary to use a lining valve. It is very important for us to select the appropriate type of the soft seal butterfly valve according to different working conditions, so that it can be better used in sewage treatment working conditions. For example, when the chloride ion content in the water is 700mg/L, both steel-lined 4F and ordinary carbon steel butterfly valves can be used, while butterfly valves made of 304 and 316 are not good under this working condition because they cannot resist corrosion well.
For another example, a situation that many engineering pipelines in the north can encounter is that due to the low temperature in winter, the properties of many materials change at low temperatures, resulting in the loss of equipment or components. If the soft-seal wafer butterfly valve made of gray iron is selected in this case and the warmth is not well maintained, the valve will easily be broken by freezing. The major reason for this situation is that the weather is not considered in the pipeline design, which makes the system work abnormally. If the buried pipeline is buried deep enough and the exposed pipe fittings are insulated in place, this type of loss can be reduced. In winter in the north, facilities such as pipelines and valves are easily damaged. In addition to the low-temperature performance of the materials, there is another important reason: the water in the pipeline or pump is frozen. In the case of the same quality, the volume of ice is larger than that of the water, pipeline or pump. If there is water, the valve can easily burst. Under such working conditions, the manufacturers of soft-seal butterfly valve suggest that water treatment in the north, except that the pipeline is buried under the frozen layer, should first be insulated before the pipeline enters water, and ensure that there is water flowing or Empty the water after parking. If there is no more water, be sure to drain the water in the pipe. Otherwise, as long as there is still water after parking, there will be freezing cracks from the weak points of the pipeline or butterfly valve.
In the enquiry reception of Tanghai Valve, we also received customer inquiries regarding municipal sewage treatment whether it would be better to choose imported soft-seal wafer butterfly valves, but our suggestion is generally that municipal sewage does not need to be imported. Because the imported price is expensive and the delivery period is long, domestic valve manufacturers can do it. Generally, the use conditions of valves in sewage treatment plant projects are relatively low, and domestic valves not only meet the needs of use, but also save costs. A better domestic factory can meet the requirements, but the design institute generally chooses imported brands according to the situation.

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:

Product Features of Electric Wafer Butterfly Valve

December 24, 2021

The electric wafer butterfly valve belongs to a variety of electric control valves. Its connection methods are mainly: flange type and wafer type. Its sealing forms mainly include: soft seal and metal hard seal. The electric wafer butterfly valve controls the switching operation of the butterfly valve through the power signal, and can be used as the shut-off valve, control valve and check valve of the pipeline system. With manual control device, once there is a power failure, it can be temporarily operated manually without affecting the use. Now the electric wafer butterfly

Types of wafer butterfly valves

valve has been continuously improved and upgraded, and the new electric wafer butterfly valve can be better used in working conditions.

The structural characteristics of a new type of electric wafer butterfly valve
1. It can still have stable sealing performance under high temperature and high pressure conditions. With a special sealing system to ensure high sealing performance in various temperature ranges from ultra-low temperature to ultra-high temperature
2. The eccentric electric wafer butterfly valve makes the valve opening resistance small. The sealing surface of the butterfly plate is an upwardly convex cone. When opening, all points on the circumferential surface of the butterfly plate are separated from the sealing ring at the same time, and solid objects are not easy to accumulate on the sealing surface. The valve closing process is completed by the elastic pressure of the sealing ring.
3. There is no interlocking phenomenon between the electric butterfly plate and the sealing ring. The sealing performance of the valve is not affected by temperature changes.
4. The butterfly valve stem is sealed with graphite pressed into a sealing ring to ensure zero leakage.

triple eccentric butterfly valve-wafer-lug-double flange-welded (5)

Features of the new electric wafer butterfly valve:
1. It adopts double eccentric structure, with tighter and tighter sealing function, and reliable sealing performance.
2. The sealing material is made of stainless steel and nitrile oil-resistant rubber pairing, which has a long service life.
3. The rubber sealing ring can be located on the valve body or on the butterfly plate, which can be applied to different characteristics of media for users to choose.
4. The butterfly plate adopts a frame structure with high strength, large flow area and small flow resistance.
5. In order to effectively prevent corrosion, the overall paint will be applied to facilitate the replacement of valve seat sealing materials for use in different media.
6. This valve has a two-way sealing function. It is not controlled by the flow direction of the medium during installation and is not affected by the spatial position. It can be installed in any direction.
7. It has the advantages of small size, light weight, reliable performance, simple matching, and large flow capacity, which is especially suitable for clean liquids and gases.

In the fierce market competition, manufacturers of electric wafer butterfly valves must adhere to the policy of developing enterprises through science and technology, continuously optimize product structure, and implement quality improvements. Increase the introduction of technology and form its own product characteristics. Providing high-quality products and satisfactory service is the tenet of Tanghai. We warmly welcome customers to inquire and patronize!

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
Video of double eccentric butterfly valve: https://youtu.be/yOw2xp3bIaE
Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0
Related news/knowledge:

What is a wafer type butterfly valve
electric wafer butterfly valve vs electric flange butterfly valve
Working principle of electric gate valve
Design Features of Electric Gate Valve

Types of Sealing Material of Electric Wafer Butterfly Valve

December 23, 2021

Electric wafer butterfly valves can be divided into soft-sealed butterfly valves and hard-sealed butterfly valves, which are distinguished according to the sealing materials of electric butterfly valves.

triple eccentric butterfly valve-wafer-lug-double flange-welded (5)

The soft sealing butterfly valve’s sealing feature is that one side of the two sides is made of metal material, and the

other side is made of elastic non-metal material, that is, one of the valve seat and the valve plate is made of elastic material, which is called “soft seal” . The hard seal butterfly valve means that both sides of the seal pair are made of metal materials or other harder materials, that is, the valve seat and the valve plate are both hard materials, which is called “hard seal”.

The difference between soft seal and hard seal of electric wafer butterfly valve
Although the soft-sealed electric wafer butterfly valve has certain strength, hardness and temperature resistance, it has good sealing performance and can achieve zero leakage. But it is not resistant to high temperature, easy to wear, and has poor mechanical properties. Our common ones are steel + rubber, steel + PTFE and so on. The hard seal of the butterfly valve has poor sealing performance, but it is resistant to high temperature, abrasion and mechanical properties. Such as steel + steel, steel + copper, steel + graphite, steel + alloy steel. The steel here can be cast iron, cast steel, alloy steel or surfacing, sprayed alloy.

The advantages and disadvantages of the soft and hard seals of the electric wafer butterfly valve

In terms of sealing performance, the soft-seal electric wafer butterfly valve is relatively good, but compared with the hard-seal butterfly valve’s corrosion resistance, the soft-seal electric butterfly valve cannot meet the process requirements for corrosive materials. The advantage of the soft sealing butterfly valve is that it has good sealing performance, but the disadvantage is that it is easy to age, wear, and has a short service

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

life. The hard-sealed butterfly valve has a long service life, but the sealing performance is relatively worse than that of the soft-sealed butterfly valve. Now there is a kind of multi-level sealing electric wafer butterfly valve that combines the advantages and disadvantages of soft sealing and hard sealing to form a complement to each other, which is a major upgrade of the product.

Different working conditions of soft and hard sealing of electric wafer butterfly valve
Let’s take a look at the different working conditions of the soft seal and the hard seal of the electric wafer butterfly valve from four aspects. The details are as follows:
1. Structure: soft-sealed electric wafer butterfly valves are mostly centerline butterfly valves, and hard-sealed electric wafer butterfly valves are mostly single eccentric butterfly valves, double eccentric butterfly valves, and triple eccentric butterfly valves.
2. Temperature resistance: soft-sealed electric butterfly valve is used in normal temperature environment. The hard-sealed electric butterfly valve can be used in low temperature, normal temperature, high temperature and other environments.
3. Pressure: The soft-sealed electric wafer butterfly valve can be used in low and normal pressure, and the hard-sealed electric butterfly valve can also be used in medium and high pressure conditions.
4. Sealing performance: The soft sealing electric butterfly valve and the triple eccentric hard sealing electric butterfly valve have better sealing performance. The triple eccentric butterfly valve can maintain a good seal under high pressure and high temperature environment.

Based on the above characteristics, the soft-sealed electric 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-sealed electric butterfly valves are mostly used in heating, gas, gas, oil, acid and alkali environments.

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:

Commonly used valve body materials of centerline wafer butterfly valve

December 21, 2021

The centerline butterfly valve can be controlled by a variety of transmission methods, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic hydraulic, electro-hydraulic, pneumatic-hydraulic, spur gear, bevel gear drive, etc. Under the action of pressure, temperature or other forms of sensing signals, it can act according to predetermined requirements, or simply open or close without relying on sensing signals. The valve

Wafer type butterfly valve with worm gear

relies on a drive or an automatic mechanism to make the opening and closing parts move up and down, sliding, swinging or rotating, thereby changing the size of the flow channel to achieve its control function. The centerline wafer butterfly valve is very suitable for the flow adjustment of the fluid, and it is also used as the opening and closing of the medium. It is a very common pipe fitting in the industrial field. Different valve body materials will be suitable for different centerline butterfly valve classifications.

The body materials of the centerline wafer butterfly valve mainly include:
Gray cast iron: suitable for low-pressure valves with a working temperature between -15 and +200°C and a nominal pressure of PN ≤ 1.6 MPa;
Black core malleable cast iron: suitable for low- and medium-pressure valves with a working temperature between -15 and +250°C and a nominal pressure of PN≤2.5MPa;
Nodular cast iron: suitable for medium and low pressure valves with a working temperature between -30 and +350°C and a nominal pressure of PN≤4.0MPa;
Carbon steel (WCA, WCB, WCC): suitable for medium and high pressure valves with operating temperature between -29 and +425°C, of which 16Mn and 30Mn have operating temperatures between -40 and +450°C, often used to replace ASTMA105 ；
Low-temperature carbon steel (LCB): suitable for low-temperature valves and valves whose working temperature is between -46~+345℃;
Alloy steel (WC6, WC9): suitable for high temperature and high pressure valves for non-corrosive media with a working temperature between -29 and +595°C; WC5, WC12: suitable for corrosion at a working temperature between -29 and +650°C High temperature and high pressure valves for sexual media;
Austenitic stainless steel: suitable for valves with corrosive media whose working temperature is between -196~+600℃;
Monel alloy: mainly suitable for valves containing hydrogen and fluorine media;
Cast copper alloy: Mainly suitable for valves for oxygen pipelines whose operating temperature is between -273 and +200℃;

Listed above are the major categories of commonly used materials for valve bodies. In each category of material, there are many functional subdivisions for different pressure levels. In addition, the valve body materials include titanium alloy (titanium valve), aluminum alloy (aluminum valve); plastic (plastic valve); ceramic (ceramic valve) and so on. Therefore, when selecting the valve body material, the valve body material suitable for the working conditions should be determined according to different uses and different pressure levels.
The centerline wafer butterfly valve is a control component in the pipeline fluid conveying system. It is used to adjust the flow direction and flow of the medium, and has the functions of opening and closing and medium adjustment. There are many varieties and specifications, which are used to control the flow of various types of fluids such as water, steam, oil, gas, mud, various corrosive media, liquid metals and radioactive fluids, and occupy an important position in the entire valve system.

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:

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:

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