manufacturer Archives

Types and Models of Butterfly Valves

January 24, 2022

With the advancement of science and technology, the production process of butterfly valves has become more and more sophisticated, and different types have been extended from this, and their uses have become more and more extensive. What are the types of butterfly valves? What is the corresponding model? This article will take you to understand the types and models of butterfly valves.

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

Types of Butterfly Valves
There are many classifications of butterfly valves, and different classification forms can divide butterfly valves into different types. Let’s talk about it specifically.
1. According to the different connection forms, it can be divided into wafer butterfly valve, flanged butterfly valve, welded butterfly valve, threaded butterfly valve, clamp butterfly valve and so on. The most commonly used connection forms are wafer butterfly valve and flanged butterfly valve.
2. According to the different transmission modes, it can be divided into handle butterfly valve, turbine butterfly valve, pneumatic butterfly valve, electric butterfly valve, hydraulic butterfly valve, solenoid valve, etc. The most common transmission methods are handle, turbine, pneumatic and electric. The handle butterfly valve and turbine butterfly valve are collectively referred to as manual butterfly valve.
3. According to the material of the sealing surface, it can be divided into soft sealing butterfly valve and hard sealing butterfly valve. The sealing performance of the soft-seal butterfly valve is better than that of the hard-seal butterfly valve. The commonly used materials for the sealing surface of the soft-seal butterfly valve are EPDM, nitrile rubber and PTFE. Hard-sealed butterfly valves are mainly used in high temperature and high pressure conditions.
4. According to different structural forms, it can be divided into centerline butterfly valve, single eccentric butterfly valve, double eccentric butterfly valve and triple eccentric butterfly valve. Among them, the midline butterfly valve generally uses a soft seal; the eccentric butterfly valve uses a hard seal. The triple eccentric butterfly valve is the valve with the best performance at present. It not only has the excellent sealing performance of the soft sealing butterfly valve, but also has the characteristics of high temperature and high pressure resistance and corrosion resistance of the hard sealing butterfly valve.
5. According to the different working pressure, it can be divided into vacuum butterfly valve (nominal pressure lower than standard atmospheric pressure), low pressure butterfly valve (nominal pressure PN<1.6MPa), medium pressure butterfly valve (nominal pressure PN2.5-6.4MPa), high pressure butterfly valve (nominal pressure PN2.5-6.4MPa) Nominal pressure PN10.0-80.0MPa), ultra-high pressure butterfly valve (nominal pressure PN>100MPa). A high-quality butterfly valve manufacturer, Tanghai Valve mainly produces low-pressure butterfly valves and medium-pressure butterfly valves.
The above is an introduction to the types of butterfly valves. For the description of butterfly valve models, you can refer to the article “Method of Representing Butterfly Valve Models”. The code name of the butterfly valve is D. The commonly used butterfly valve models include D71X, D371X, D671X, D971X for the wafer type of the soft-sealed butterfly valve, and D41X, D341X, D641X, and D941X for the flange type. Among them, X represents the rubber material. Pipes with corrosive media can be replaced with F fluoroplastics. For hard sealing, you only need to change X or F, that is, the material of the sealing surface, to H, that is, the metal material.

The types and models of butterfly valves are introduced here. For more butterfly valve information, you are welcome to visit the official website of Tanghai 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

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
Video of PTFE butterfly valve: https://youtu.be/Lutith_TJD0

Advantages and Disadvantages of Triple Eccentric Butterfly Valves

January 21, 2022

The triple eccentric butterfly valve is a new type of butterfly valve product. Before the advent of the triple eccentric butterfly valve, the soft sealing butterfly valve and the single eccentric double eccentric metal hard sealing butterfly

triple eccentric butterfly valve-

valve were the most used in industrial pipelines. These two types of butterfly valves have their own advantages, but also have obvious disadvantages. The advantage of soft sealing butterfly valve is that it has good sealing performance and can achieve zero leakage; the disadvantage is that it is not suitable for high temperature and high pressure environment and is not resistant to wear. The advantage of hard sealing butterfly valve is that it can adapt to high temperature and high pressure working conditions, but the sealing performance is very poor. In order to solve the shortcomings of the two types of butterfly valves and better serve our production work, the triple eccentric butterfly valve came into being and has been widely used.

Advantages of triple eccentric butterfly valve
The triple eccentric butterfly valve also belongs to the metal hard sealing butterfly valve. The technology makes the triple eccentric butterfly valve more resistant to high temperature and high pressure environment and more corrosion resistant than traditional butterfly valve products. At the same time, due to the unique design of the triple eccentricity, the valve is very easy to operate. When opening and closing, the disc and the valve body have no friction. When the valve is closed, the torque of the transmission mechanism increases to provide a compensation seal, which greatly improves the triple eccentricity. The sealing performance of the butterfly valve also prolongs the service life of the butterfly valve. So what do the three eccentricities of the triple eccentricity mean?
1st eccentric: The valve shaft is located behind the valve plate shaft, allowing the seal to have a complete tight encircling contact with the entire valve seat.
The second eccentricity: the centerline of the valve shaft is offset from the centerline of the pipe and valve, which is free from the interference of valve opening and closing.
3rd eccentricity: The valve seat cone shaft is offset from the centerline of the valve shaft, which eliminates friction during closing and opening and achieves a uniform compression seal around the entire valve seat.

Disadvantages of triple eccentric butterfly valve
No matter how perfect things are, there will be more or less defects and imperfections, and the triple eccentric butterfly valve is no exception. Its shortcomings have the following two points:
1. Due to the special process of the triple eccentric butterfly valve, the structure of the butterfly plate will be relatively thick, so if a butterfly valve with a triple eccentric structure is used on a small-diameter pipeline, the resistance of the butterfly plate to the circulating medium in the pipeline will be very large in the open state, and the flow of The resistance is large, so generally speaking, the triple eccentric butterfly valve is not suitable for small diameter pipelines below DN200.
2. In the normally open pipeline, the sealing surface of the valve seat of the triple eccentric butterfly valve and all layers of the sealing ring on the butterfly plate will be washed by the front, which will affect the sealing performance of the valve for a long time.

The above is the introduction of Tanghai valve for the advantages and disadvantages of triple eccentric butterfly valve. If you have purchase requirements for triple eccentric butterfly valves, you are 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:

Which valves are used for wastewater and sewage treatment

January 20, 2022

Which valves are used for wastewater and sewage treatment? The continuous increase of water pollution in my country has made the sewage treatment and regeneration industry receive unprecedented attention. In the sewage treatment pipeline system, the valve plays a very important role.

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

Definition of sewage treatment
Sewage treatment: The process of purifying sewage in order to make it meet the water quality requirements for discharge into a body of water or for reuse. Sewage treatment is widely used in construction, agriculture, transportation, energy, petrochemical, environmental protection, urban landscape, medical treatment, catering and other fields, and is increasingly entering the daily life of ordinary people.

Sewage treatment classification
According to the classification of sewage sources, sewage treatment is generally divided into production sewage treatment and domestic sewage treatment. Production sewage includes industrial sewage, agricultural sewage and medical sewage, etc., while domestic sewage is sewage generated in daily life, which refers to the complex mixture of various forms of inorganic and organic substances, including: ① floating and suspended solid particles; ② glue shape and gel-like diffusion; ③ pure solution.
According to the quality of water pollution, there are two types of water pollution: one is natural pollution; the other is man-made pollution. At present, man-made pollution is the most harmful to water bodies. Water pollution can be divided into three categories: chemical pollution, physical pollution and biological pollution according to the different pollution impurities. The main pollutants are: (1) industrial wastewater discharged without treatment; (2) domestic sewage discharged without treatment; (3) farmland sewage with extensive use of chemical fertilizers, pesticides, and herbicides; (4) industrial waste and domestic garbage piled up by the river ; ⑸ soil erosion; ⑹ mine sewage.

Sewage treatment valve
Modern sewage treatment technology can be divided into primary, secondary and tertiary treatment according to the degree of treatment. Generally, the degree of sewage treatment is determined according to the water quality and the destination of the treated water. The valves used at each level are also different.
primary treatment
It mainly removes suspended solid pollutants in sewage, and most of the physical treatment methods can only complete the requirements of primary treatment. After primary treatment of sewage, BOD can generally be removed by about 30%, which does not meet the discharge standard. The primary treatment belongs to the preprocessing of the secondary treatment. Valves and their pipeline accessories are used: knife gate valve, triple eccentric butterfly valve, filter, etc.
secondary processing
It mainly removes colloidal and dissolved organic pollutants (BOD, COD substances) in the sewage, and the removal rate can reach more than 90%, so that the organic pollutants can meet the discharge standard, and the suspended solids removal rate can reach 95%, and the effluent effect is good. The valves used are soft-sealed butterfly valves, gate valves, ball valves, check valves, etc.
tertiary treatment
Further treatment of refractory organic matter, nitrogen and phosphorus and other soluble inorganic matter that can lead to eutrophication of water bodies. The main methods are biological denitrification and phosphorus removal, coagulation sedimentation, sand filtration, activated carbon adsorption, ion exchange and electrodialysis. The valves used are wafer butterfly valve, gate valve, ball valve, check valve, rubber soft joint, 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: https://youtu.be/NuSZH_AJcwY
Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0
Video of dual plate wafer check valve: https://youtu.be/XqRRI7o-LFI
Video of knife gate valve: https://youtu.be/vFSbTF_FGXM
Video of resilient seated gate valve: https://youtu.be/AI-LT1dy2sU

Precautions for the application of fluorine-lined valves

January 19, 2022

Appropriate selection and application of fluorine-lined anti-corrosion valves is a matter of concern to everyone in engineering. Tanghai Valve puts forward the following views based on years of field application experience for your reference. We are specialised in the production of fluorine lined butterfly valves.

lug butterfly valve-lined-PTFE-DI body (1)

The price of fluorine-lined butterfly valves is much lower than that of corrosion-resistant stainless steel valves and Hastelloy valves. Some metal valves with strong corrosive media cannot be used, but only plastic-lined valves can be used well. However, the plastic-lined valve must be suitable for application. It is hoped that several technical conditions such as application pressure and application temperature should be used. Take our company’s products as an example to illustrate the following:
(1) The temperature of the medium used in the fluorine-lined valve: Usually, the fluorine plastic used in the fluorine-lined valve is F46 (FEP), and the temperature of the medium used cannot exceed 150 °C (the medium temperature can reach 150 °C in a short time, and the temperature of the long-term use It should be around 120℃), otherwise, the F46 lining of various parts of the valve is easy to soften and deform, resulting in the valve not closing and the leakage is large.
If the temperature of the medium used by the user is below 180 °C for a short time and below 150 °C for a long time, another fluoroplastic, PFA, can be used, but the price of fluoroplastic lined with PFA is more expensive, so it should be used in advance when matching. Inquiry.
(2) Do not have negative pressure. Fluoroplastic-lined valves should avoid negative pressure in the pipelines used. If there is negative pressure, it is easy to cause the fluoroplastic-lined layer of the valve cavity to be sucked out (bulged) and shelled, resulting in failure of the valve to open and close.
(3) The pressure and differential pressure should be controlled within the allowable range. Especially the fluorine-plastic-lined regulating valve and globe valve sealed by bellows. Because the bellows is made of tetrafluoro material, the pressure is high and the pressure difference is high, which can easily lead to the rupture of the bellows.
Bellows-sealed fluoroplastic-lined regulating valve can be changed to PTFE packing seal if the operating condition pressure and differential pressure are high.
(4) The medium conditions used in the fluoroplastic valve should not have hard particles, crystallization, impurities, etc., so as to prevent the valve from breaking the valve core, the fluoroplastic layer of the valve seat or the tetrafluoro bellows during the opening and closing operation. For the medium with hard particles, crystals and impurities, when selecting, the valve core and valve seat can be changed to Hastelloy, but additional inquiry is required.

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:

Introduction to Common Butterfly Valve Materials

January 14, 2022

This article makes an introduction to the commonly used butterfly valve materials. For butterfly valves, you should already have a certain understanding. There are many types of butterfly valves. According to the different connection forms, they can be divided into wafer butterfly valves and flanged butterfly valves; according to different sealing surface materials, they can be divided into soft sealing butterfly valves and metal hard sealing. Butterfly valve;

Types of wafer butterfly valves

according to the different driving methods, it can be divided into handle butterfly valve, turbine butterfly valve, pneumatic butterfly valve, electric butterfly valve and so on. So what are the commonly used butterfly valve materials?
Commonly used butterfly valve materials are mainly cast iron, cast steel, stainless steel three categories. Each material can be further subdivided. Below we will give an introduction to these three types of butterfly valve materials.

Category 1: Cast Iron
Cast iron is subdivided into four categories: gray cast iron, malleable cast iron, ductile iron, and nickel cast iron. This article mainly introduces the two main cast iron materials made by Tanghai valve: gray cast iron, ductile iron and stainless steel.

lug butterfly valve-lined-PTFE-DI body (1)

Gray cast iron is cast iron with flake graphite, because the fracture is dark gray when broken, so it is called gray cast iron. Gray cast iron is the most widely used cast iron, and its output accounts for more than 80% of the total output of cast iron. The casting performance, cutting performance and wear resistance of gray cast iron are very good. Its disadvantage is that its strength, plasticity and toughness are lower than other cast irons.
Grey cast iron is used as the material of butterfly valve, which is usually suitable for weak acid and weak alkali media such as water and air, but not suitable for pipelines with perhydrochloric acid and nitric acid media.
Ductile iron is a high-strength cast iron material with very high strength, toughness and wear resistance, and its comprehensive performance is close to that of steel. At present, the application range of ductile iron is second only to gray cast iron. We often say “replace steel with iron”, which refers to ductile iron.

U type flange butterfly valve (4)

Ductile iron is used as the material of butterfly valve, which has certain corrosion resistance and performance is much higher than that of butterfly valve made of gray iron. The applicable medium includes steam, general gas and oil.

The second category: cast steel
Cast steel is a cast iron alloy, which is a general term for iron-based alloys used to produce castings that do not undergo eutectic transformation during solidification. The advantages of cast steel are greater design flexibility and variability, increased overall structural strength and a wide range of weight variations. Using cast steel as the butterfly valve material, the performance is better than that of cast iron but not as good as stainless steel. Butterfly valve made of cast steel is suitable for steam, non-corrosive gas, oil, etc.

The third category: stainless steel
Stainless steel refers to steel that is resistant to weak corrosive media such as air, steam, and water, and chemically corrosive media such as acid, alkali, and salt, also known as stainless acid-resistant steel. Generally, the butterfly valve made of stainless steel has the best performance and can be used in more severe working conditions. It is used in some ultra-high temperature, ultra-low temperature and strong acid-base corrosive medium pipelines. Wear-resistant and long-lasting.

The above is the introduction of commonly used butterfly valve materials. Generally speaking, the price of stainless steel butterfly valve is the highest, and gray cast iron is the cheapest. If you want to know more about butterfly valve, you are welcome to visit Tanghai 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

Video of center-lined butterfly valve:

The role and application of gate valve

January 7, 2022

This article introduces you to the function of gate valve, and then understands the purpose of gate valve. The gate valve is a very important control component on the pipeline that transports the fluid medium. The structure of the gate valve is composed of a valve body, a valve cover, a valve stem, a gate plate, a sealing ring, and a driving device. The driving device is usually a hand wheel, and it can also be equipped with a pneumatic or electric actuator.

DIN-F4-BB-NRS-soft seated-wedge gate valve-DN100-PN16-copper holding ring-handwheel (3)

The gate of the gate valve is a disc shape, and the valve stem is driven to realize the opening and closing of the valve. The movement direction of the valve stem and the gate is perpendicular to the valve body passage and the direction of fluid flow in the pipeline. The gate valve has only two states, fully open and fully closed, so it can only be used to cut off the flow of the medium in the pipeline, and cannot adjust the flow rate. In addition, when the gate valve is opened and closed, the stroke distance of the gate is long. Although the opening and closing is labor-saving, it takes time. Therefore, the function of the gate valve is very suitable for use in pipelines that do not need to be opened and closed frequently, and used as a cut off or connected to the circulating medium in the pipeline.
The gate of the gate valve has two sealing surfaces. When the gate valve is closed, the sealing surface of the gate can be pressed against the seat on one side by the pressure of the medium to achieve sealing, which is self-sealing. The gate is basically a forced sealing type, that is, when the gate valve is closed, it needs to rely on the external force of the medium to force the gate to the valve seat to ensure the sealing performance of the sealing surface of the gate valve.
Gate valves can be divided into open-stem gate valves and concealed-stem gate valves according to their structural form. The functions of the two structural forms of gate valves are not much different, and the more difference lies in the use environment.
1. The stem of the rising stem gate valve is exposed, and the opening and closing state of the valve can be observed intuitively when the valve is opened and closed, so as to avoid misoperation. But also because the valve stem is exposed, the height of the rising stem gate valve, which is originally large in height, is even greater. Therefore, the rising stem gate valve is suitable for use in places that require a lot of operating space, and is not suitable for working conditions with narrow space.
2. The valve stem of the concealed stem gate valve is inside the valve body, so the on-off state of the valve cannot be directly observed, and another indicating device is required. However, because the valve stem is in the valve body, the volume of the dark-stem gate valve is smaller than that of the open-stem gate valve, and it is more suitable for use in occasions where the operating space is small and the location is limited and the pipeline is dense.
When the gate valve is fully opened, there is no obstruction when the medium flows through the inside of the valve body passage, and the flow resistance is almost zero. In addition, the valve body channel of the gate valve is symmetrical on both sides, the medium can flow in both directions, and it is not affected by the flow direction of the medium during installation. The gate valve has a wide range of applications due to its good manufacturing process. Gate valves have a wide range of uses, and are widely used in water conservancy systems, water supply and drainage systems, as well as petroleum, chemical, electric power, urban construction, and fire protection industries.

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:

How many types of gate valves? gate valve classification

January 6, 2022

How many kinds of gate valves are there? Which gate valve is suitable for which occasion? How many kinds of gate valves are there?

Commonly used gate valves are as follows:

DIN-F4-BB-NRS-soft seated-wedge gate valve-DN100-PN16-copper holding ring-handwheel (3)

1. Gray iron gate valve: including gray iron open rod gate valve and gray iron dark rod gate valve, this gate valve is suitable for municipal construction, water treatment, water supply and drainage, water conservancy engineering and other fields.

2 ductile iron gate valve: usually for soft seal gate valve, and divided into exposed rod and hidden rod. This kind of gate valve is mainly used in sewage treatment, building fire control, water supply and drainage engineering and other municipal engineering pipeline.

Gray cast iron gate valves and ball valve gate valves are cast iron gate valves. These gate valves are mostly used in normal temperature and low pressure pipelines, and the medium used is mostly water.

3 carbon steel gate valve and stainless steel gate valve: these two kinds of gate valves are used in high temperature and high pressure pipelines, the use of medium for steam, oil and so on. Applications include petroleum, chemical, metallurgy and so on.

4. Knife gate valve: suitable for all kinds of fluid media such as pulp, mud, sewage, powder, syrup, coal pulp, ash, slag-water mixture, etc.

Knife gate valve (6)

The above are just a few common gate valves. In fact, gate valves are not only the above, according to the structure of gate valves, different standards, connection, drive, etc., can be divided into many types.

According to the structure:

1. Implicit stem gate valve: stem nut is placed inside the valve body, in direct contact with the medium, often fixed on the gate. Through the rotation of the stem, the stem nut drives the lubrication plate up and down to complete the opening and closing.

2. Plain stem gate valve: the stem trapezoidal thread is placed outside the valve body, on the upper part of the stem. By rotating stem nut, stem drives gate synchronous rise and fall, realize valve opening and closing, easy to identify the valve. On and off state to avoid misoperation.

3. Flat gate valve: the sealing face is parallel to the vertical center line, so the valve body is parallel to the sealing face on the gate. This valve is the most common type of double gate.

4. Wedge valve: the sealing face is at a certain Angle with the vertical center line, that is, the two sealing faces are wedge valves.

According to different standards: gb gate valve, American standard gate valve, German standard gate valve, Japanese standard gate valve.

According to the connection mode: flange gate valve, welding gate valve, threaded gate valve.

According to the pressure grade: high pressure gate valve, medium pressure gate valve, low pressure gate valve.

According to the driving mode: electric gate valve, pneumatic gate valve, manual gate 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

Video of knife gate valve:

Video of resilient seated gate valve:

How to judge whether the check valve is qualified in the factory pressure test

January 5, 2022

Check valve refers to the valve that actively opens and closes the valve flap by relying on the activity of the medium itself to avoid the back flow of the medium. It is also called check valve, one-way valve, reverse flow valve, and back pressure valve. The check valve is a kind of active valve whose primary effect is to avoid the back flow of the medium, avoid the reversal of the pump and drive motor, and the discharge of the container medium.

dual plates check valve photos-normal sealing (1)

Check valves can also be used to supply supplementary lines to auxiliary systems whose pressure may rise above the system pressure. The effect of this type of check valve is to only allow the medium to move in one direction and block the movement in the opposite direction. Usually this kind of valve works actively. Under the effect of the fluid pressure moving in one direction, the valve flap opens; when the fluid moves in the opposite direction, the self-coincidence of the fluid pressure and the valve flap will affect the valve seat, and then the movement will be cut off.
Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis). The swing check valve has a hinge mechanism and a valve disc like a door freely leaning on the surface of the slanted valve seat. In order to ensure that the valve clack can reach the proper position of the valve seat surface every time, the valve clack is designed in a hinge mechanism so that the valve clack can meet the swing space and make the valve clack truly and comprehensively touch the valve seat. The valve clack can be made of metal, or inlaid with leather, rubber, or covered with a composition, depending on the requirements of performance. When the swing check valve is fully opened, the fluid pressure is almost unblocked, so the pressure drop through the valve is relatively small.
The valve disc of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except that the disc can be lifted and lowered freely, the rest of the valve is the same as a shut-off valve. The fluid pressure lifts the disc from the sealing surface of the valve seat, and the backflow of the medium causes the disc to fall back to the seat and cut off the movement. According to the operating conditions, the valve disc can be an all-metal structure, or it can be inlaid with a rubber pad or a rubber ring on the disc holder. Like the stop valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow rate of the swing check valve is restricted. rare.

all types of check valve and structures -code names-photos

Check valve experiment status
The flap axis of the lift check valve is in an orientation straight with the horizontal; the channel axis of the swing check valve and the flap axis are in an orientation approximately parallel to the horizontal line.
In the strength test, the test medium is introduced from the inlet end to the specified value, and the other end is closed, and the valve body and bonnet are qualified without leakage.
In the sealing test, the test medium is introduced from the outlet end, and the sealing surface is checked at the inlet end. No leakage at the packing and gasket is qualified.

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 dual plate wafer check valve:

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:

Posts

Types and Models of Butterfly Valves

Advantages and Disadvantages of Triple Eccentric Butterfly Valves

Which valves are used for wastewater and sewage treatment

Precautions for the application of fluorine-lined valves

Introduction to Common Butterfly Valve Materials

The role and application of gate valve

How many types of gate valves? gate valve classification

How to judge whether the check valve is qualified in the factory pressure test

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

Structure of Triple Eccentric Metal seated Butterfly Valve (Picture)

TH VALVE • PROFESSIONAL VALVE MANUFACTURER

GET IN TOUCH WITH US