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The role and application of gate valve

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)

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:
Design Features of Electric Gate Valve
How many types of gate valves?
Difference between Soft seal gate valve and hard seal gate valve
Classification and advantages of gate valve

How many types of gate valves? gate valve classification

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)

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)

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:
Pneumatic gate valve model preparation method
The difference between knife gate valve and ordinary gate valve
Valve body and material classification

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

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)

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

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 valvegate valvecheck valveglobe valveknife 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:

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Check valve and its working principle
Introduction of cast steel lift swing check valve
Features of Stainless Steel Valves
All types of check valve and its structures

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

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)

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:

Ways to Extend the Service Life of Valves
The difference between fluorine-lined butterfly valve and metal butterfly valve
Classification and selection of fluorine-lined valves
electric fluorine-lined butterfly valve vs electric metal seated butterfly valve

Structure of Triple Eccentric Metal  seated Butterfly Valve (Picture)

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

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:
What is a triple eccentric metal seated butterfly valve
Application of double eccentric butterfly valve and triple eccentric butterfly valve
Precautions for the use of triple eccentric metal seated butterfly valve
What are the characteristics of the hard seal butterfly valve

Application of Soft Seal Wafer Butterfly Valve in Sewage Treatment

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)

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:

Resilient seated vs metal seated wafer butterfly valve
Gate valve has a broad market in the field of sewage treatment
Current status and development of Chinese valves
Process design of check valve

Product Features of Electric Wafer Butterfly Valve

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

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)

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 valvegate valvecheck valveglobe valveknife 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

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)

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)

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 valvegate valvecheck valveglobe valveknife 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:

Related news/knowledge:
What are the characteristics of the soft sealing butterfly valve
Fluorine-lined butterfly valve vs metal seated butterfly valve
What are the characteristics of the hard seal butterfly valve
pneumatic fluorine-lined butterfly valve vs pneumatic hard-sealed butterfly valve

Commonly used valve body materials of centerline wafer butterfly valve

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

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 valvegate valvecheck valveglobe valveknife 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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Resilient seated vs metal seated wafer butterfly valve

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)

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)

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 valvegate valvecheck valveglobe valveknife 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:

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Characteristics of soft seal /resilient seated gate valves
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