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The difference between fluorine-lined butterfly valve and metal butterfly valve

Butterfly valve is one of the most commonly used valves in industrial pipelines. It has a simple structure and is mainly composed of a valve body, a valve stem, a butterfly plate and a sealing ring. It is easy to operate and can be equipped with different driving devices, such as turbine devices, electric devices, and pneumatics. Equipment, etc., to adapt to more working conditions. Compared with other valves of the same caliber, the overall cost of butterfly valves can be reduced by 1.5 to 2 times, which is economical and practical. Therefore, butterfly valves are most suitable for large-diameter valves and are often used in occasions with larger calibers and flow rates.

Fluorine lined butterfly valve-PTFE-WAFER (8)

Fluorine lined butterfly valve-PTFE-WAFER (8)

According to the sealing form of the butterfly valve, we can divide the butterfly valve into two categories: soft sealing butterfly valve and hard sealing butterfly valve. The two butterfly valves with different sealing forms play different roles in the corresponding application pipelines, and it can even be said that there are big differences. Therefore, users should understand the difference between the two types of butterfly valves when choosing butterfly valves, and choose butterfly valve products reasonably and correctly according to their own operating conditions.
Among soft seal butterfly valves and hard seal butterfly valves, our most common and commonly used ones are soft seal fluorine lined butterfly valves and metal seated butterfly valves. The difference between fluorine lined butterfly valves and metal seal butterfly valves is that fluorine lined butterfly valves are generally used for flowing media containing corrosion. In the flexible pipeline, the sealing effect is excellent, and zero leakage can be achieved. However, due to its own material limitation, this type of butterfly valve is only suitable for use in normal temperature and pressure

triple offset butterfly valve-double flange- (4)

triple offset butterfly valve-double flange- (4)

conditions. The metal-sealed butterfly valve can be used in working conditions with relatively high temperature and pressure, and it also has certain anti-corrosion performance, but its sealing performance is poor. Specifically, the difference between fluorine-lined butterfly valve and metal sealing butterfly valve is as follows:
1. The difference in structure:
Both sides of the metal seal butterfly valve seal pair are made of metal materials. As for the fluorine-lined butterfly valve of soft sealing butterfly valve, the butterfly plate and valve seat are both wrapped with PTFE;
2. The difference in sealing performance:
The sealing material of fluorine-lined butterfly valve is tetrafluoroplastic, which has excellent sealing performance, but it is prone to aging, abrasion and short service life. The sealing performance of the metal sealing butterfly valve is relatively poor, but it is corrosion-resistant, wear-resistant and has a long service life.
3. The difference in applicable working conditions:
The fluorine-lined butterfly valve has strong corrosion resistance and can be used in corrosive media pipelines. It is only suitable for normal temperature and pressure environments. The metal sealing butterfly valve has poor sealing performance and is generally used in high temperature and high pressure environments.
4. The difference in manufacturing process:
In terms of working principle, the difference between fluorine-lined butterfly valve and metal-sealed butterfly valve is not big. The difference in manufacturing process between the two is mainly in the valve seat. The seat material of the fluorine-lined butterfly valve is non-metallic PTFE and metal-sealed butterfly valve. The valve seat is made of metal materials, and the commonly used materials are copper alloy, chromium stainless steel, stellite alloy, nickel-based alloy and so on.

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

Related news/knowledge:
electric fluorine-lined butterfly valve vs electric metal seated butterfly valve
Classification and selection of fluorine-lined valves
Fluorine-lined valve instructions | Installation instructions
pneumatic fluorine-lined butterfly valve vs pneumatic hard-sealed butterfly valve

Advantages and disadvantages of butterfly valve and structure diagram

Advantages and disadvantages of butterfly valve and structure diagram
The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve opening and closing or adjustment. The butterfly valve is usually less than 900 from fully open to fully closed. The butterfly valve and the butterfly rod themselves are not self-locking. For the positioning of the butterfly plate, a worm gear reducer must be installed on the valve rod. The use of worm gear reducer can not only make the disc plate have self-locking ability, make the disc plate stop at any position, but also improve the operation performance of the valve.

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

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

The industrial butterfly valve is characterized by high temperature resistance, high applicable pressure range, large nominal diameter of the valve, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of a rubber ring. The large high temperature butterfly valve is made of steel plate welding, and is mainly used for flue ducts and gas pipes of high temperature media.
(1) Advantages of butterfly valve:
1. It is convenient and quick to open and close, labor-saving, low fluid resistance, and can be operated frequently.

Wafer and Lug type butterfly valve structures & parts

Wafer and Lug type butterfly valve structures & parts

2. Simple structure, small size and light weight.
3. Mud can be transported, and the accumulation of liquid at the pipe mouth is the least.
4. Under low pressure, good sealing can be achieved.
5. Good adjustment performance.
(2) Disadvantages of butterfly valves:
1. The working pressure and working temperature range are small.
2. Poor airtightness.
(3) Installation and maintenance of butterfly valve:
1. During installation, the valve disc should be stopped in the closed position.
2. The opening position should be determined according to the rotation angle of the butterfly plate.
3. For the butterfly valve with bypass valve, the bypass valve should be opened before opening.
4. The installation should be carried out according to the installation instructions of the manufacturer, and the heavy-weight butterfly valve should be installed with a firm foundation.
Related knowledge: the principle of butterfly valve structure

Double flange butterfly valve structure

Double flange butterfly valve structure

Related products: Electric butterfly valve Pneumatic butterfly 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

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Fluorine-lined butterfly valve vs metal seated butterfly valve

The difference and selection of fluorine-lined butterfly valve and metal seated butterfly valve
As one of the most commonly used valves in process pipelines, butterfly valves are not only simple in structure, easy to operate, and equipped with different driving devices, but also can form a variety of control methods, such as electric butterfly valves, hydraulic butterfly valves, pneumatic butterfly valves, etc.! Moreover, butterfly valves are often used in occasions with large caliber and flow. Compared with other valves of the same caliber, the cost can be reduced by 1.5 to 2 times, which is economical and practical!

Fluorine lined butterfly valve-PTFE-DOUBLE FLANGE (2)

Fluorine lined butterfly valve-PTFE-DOUBLE FLANGE (2)

According to the different sealing forms of butterfly valves, they can be divided into two categories, one is soft seal and the other is metal seated! The two butterfly valves with different sealing forms play different roles in the relatively used pipelines. In a sense, there are still big differences! When choosing, users should have a detailed understanding and awareness of the difference between the two!

Take the most common soft-sealed fluorine-lined butterfly valves and metal hard-sealed butterfly valves, fluorine-lined butterfly valves are generally used for pipelines containing corrosive media, and the sealing effect can reach zero leakage, but it is only suitable for normal temperature and pressure! The hard-sealed butterfly valve is relatively high in temperature and pressure, but the sealing and corrosion resistance are not as good as the soft-sealed butterfly valve!
1. From the structure: The metal seated butterfly valve refers to the metal material or other harder materials on both sides of the sealing pair. For soft sealing butterfly valves, the two contacting sealing surfaces can be separate or all of soft materials. For example, fluorine-lined butterfly valve means that the butterfly plate and valve seat are both wrapped in PTFE;

triple offset butterfly valve-double flange- (5)

triple offset butterfly valve-double flange- (5)

2. In terms of sealing performance: The advantage of the soft-sealed fluorine-lined 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 life. The metal seated butterfly valve has a long service life, but the sealing performance is relatively worse than that of the soft seal.
3. From the conditions of use: The soft-sealed fluorine-lined butterfly valve is used in normal temperature and pressure environments, while the hard-sealed butterfly valve can be used in low temperature, normal temperature, high temperature and other environments. Generally, it can be used for higher pressure, but the soft seal is not. However, the fluorine-lined butterfly valve has Super corrosion resistance!
4. From the manufacturing aspect: As for the manufacturing, from the principle point of view, the difference between the two is not big, mainly the difference in the valve seat. The soft-sealed fluorine-lined butterfly valve is a non-metallic structure, and the hard-sealed butterfly valve is a metal structure. It is necessary to consider the metal structure. The relationship between the hardness, the working conditions, what medium is used, and so on.

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

Related news /products:
electric fluorine-lined butterfly valve vs electric metal seated butterfly valve;
pneumatic fluorine-lined butterfly valve vs pneumatic hard-sealed butterfly valve;
Classification and selection of fluorine-lined valves;

Vulcanized vs soft seated/back-up butterfly valve

The difference between rubber-lined butterfly valve and rubber butterfly valve (illustration)
The difference between a rubber-lined butterfly valve and a rubber butterfly valve, and the difference between a rubber-lined butterfly valve and a plastic-lined butterfly valve. The rubber-lined butterfly valve uses a high-temperature method to vulcanize the rubber and the valve body into one body. It has very high corrosion resistance and is generally used. To control some corrosive fluids with strong acidity and alkalinity. The rubber butterfly valve is a butterfly valve whose seal is a rubber seal, which is generally called a valve seat, and is separately installed into a whole.

Fluorine lined butterfly valve-PTFE-WAFER (8)

Fluorine lined butterfly valve-PTFE-WAFER (8)

At normal temperature, the abrasion resistance of natural soft rubber is much better than that of nitrile rubber, but their high temperature resistance is the highest limit within 80 degrees, and it is not suitable for use if it exceeds.
The difference between a fully lined butterfly valve and a half lined butterfly valve:
1. Semi-lined butterfly valve means: the butterfly valve is not lined with rubber, but the place where the butterfly valve is connected to the valve body is lined with rubber;
2. Fully lined butterfly valve means: the butterfly plate of the butterfly valve and the part connected with the valve body are lined with rubber. The difference between rubber-lined butterfly valve, fluorine-lined butterfly valve and plastic-lined butterfly valve: rubber-lined butterfly valve and fluorine-lined butterfly valve are only one kind of plastic-lined butterfly valve.

wafer type butterfly valve (6)

wafer type butterfly valve (6)

The sealing materials in the rubber-lined butterfly valve are:
Applicable temperature of hard rubber NR: -10℃~85℃,
Applicable temperature of soft rubber BR: -10℃~85℃,
Suitable temperature for butyl rubber IIR: -10℃~120℃,
Applicable temperature of neoprene CR: -10℃~105℃;
The sealing materials in the fluorine-lined butterfly valve are:
Use temperature of polyperfluoroethylene FEP (F46): -85℃~150℃,
Polytetrachloroethylene PTFE (F4) operating temperature: -200℃~180℃,
Polytrifluoroethylene PCTEF (F3) operating temperature: -195℃~120℃,
Polypropylene: RPP operating temperature: -14℃~80℃,
Polyvinyl chloride: rigid) PVC service temperature: 0℃-55℃,
Polyvinylidene chloride PVDF (F2) operating temperature: -70℃~100℃,
Polyolefin: PO Operating temperature: -58℃~80℃.

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

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Prevention and treatment of valve corrosion

What is valve corrosion?
Corrosion of the valve is usually understood as the damage to the metal material of the valve under the action of a chemical or electrochemical environment. Since the “corrosion” phenomenon occurs in the spontaneous interaction between the metal and the surrounding environment, how to isolate the metal from the surrounding environment or use more non-metallic synthetic materials is the focus of corrosion prevention. The valve body (including the bonnet) of the valve occupies most of the weight of the valve and is in constant contact with the medium. Therefore, the selection of the valve is often based on the material of the valve body.

The corrosion of the valve body is nothing more than two forms, namely chemical corrosion and electrochemical corrosion. Its corrosion rate depends on the temperature, pressure, chemical properties of the medium and the corrosion resistance of the valve body material. The corrosion rate can be divided into six levels:
1. Complete corrosion resistance: the corrosion rate is less than 0.001 mm/year;
2. Extremely resistant to corrosion: the corrosion rate is 0.001 to 0.01 mm/year;
3. Corrosion resistance: the corrosion rate is 0.01 to 0.1 mm/year;
4. Still corrosion resistant: the corrosion rate is 0.1 to 1.0 mm/year;
5. Poor corrosion resistance: the corrosion rate is 1.0 to 10 mm/year;
6. Not resistant to corrosion: the corrosion rate is greater than 10 mm/year.

How to prevent valve corrosion?
The anti-corrosion of the valve body is mainly based on the correct selection of materials. Although there are abundant anti-corrosion materials, it is not easy to choose the right one, because the problem of corrosion is very complicated. For example, sulfuric acid is very corrosive to steel when the concentration is low, and when the concentration is high, the steel is produced. Passivation film can prevent corrosion; hydrogen only shows strong corrosiveness to steel under high temperature and high pressure. The corrosion performance of chlorine is not great when it is in a dry state, but it is very corrosive when there is a certain humidity, and many materials cannot be used. . The difficulty in selecting valve body materials lies in not only considering corrosion issues, but also factors such as pressure resistance and temperature resistance, whether it is economically reasonable, and whether it is easy to purchase. So it must be attentive.
1. The second is to take lining measures, such as lining lead, lining aluminum, lining engineering plastics, lining natural rubber and various synthetic rubbers. If the media conditions permit, this is an economical method.
Second, again, when the pressure and temperature are not high, the main material of the fluorine-lined valve can often be very effective in preventing corrosion.
3. In addition, the outer surface of the valve body is also corroded by the atmosphere, and generally steel materials are protected by painting.

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

Fluorine-lined valve instructions | Installation instructions

Fluorine-lined valve instructions | Installation instructions
1 The fluorine-lined valve flange cover cannot be opened at will. Unless it is ready to be connected to the pipeline, the PTFE flange surface may be bumped, scratched or deformed due to temperature differences and foreign objects, which may affect the sealing. If the cover is moved due to inspection needs, It is also necessary to quickly reset the cover plate after inspection to protect the PTFE flange surface.

Fluorine lined butterfly valve-PTFE-WAFER (9)

Fluorine lined butterfly valve-PTFE-WAFER (9)

2 When the fluorine-lined valve is connected to the pipeline, the gasket is generally no longer used alone, but when it is connected with the flange surface of dissimilar materials (metal surface, etc.), appropriate gaskets should be used to protect the PTFE flange surface.
3 During the use of the fluorine-lined valve, if a leak occurs at a higher temperature, the system temperature should be lowered to room temperature first, and then the cause should be investigated and repaired.
4 During installation, the flange nuts should be evenly tightened in the diagonal direction (symmetrically), and matched with appropriate torque: a If the flange sealing surface leaks and the leak location nut is locked, the leak location nut should be loosened at this time Half a circle, and then apply the same torque to the opposite side to lock it again; b If the above method still does not stop the leakage, check whether the PTFE flange surface has unevenness, indentation, scratches, and then it can be leveled with fine gauze paper or cloth. reconnect.
5 It is not allowed to do any high temperature welding work on the fluorine-lined valve to avoid permanent damage to the lining layer.
6 Fluorine-lined valves should be stored in a dry and ventilated room. Stacking is strictly prohibited.
7 Fluorine-lined valves after maintenance must be tested and qualified according to relevant standards before they can be installed.
8 When manually operating the fluorine-lined valve, it is not allowed to force the valve to be opened or closed with the help of other levers.
9 When installing fluorine-lined valves with directional requirements, pay attention to the flow of the medium in the direction indicated by the arrow on the valve body, and ensure convenient operation and maintenance.
10 The sealing pair of fluorine-lined valves stored for a long time should be in a slightly separated state to avoid permanent deformation of the sealing surface under long-term pressure, which will affect the sealing performance and service life.

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

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