characteristics Archives

Comparison of the characteristics of wafer butterfly valves and flanged butterfly valves

November 4, 2021

To find out what is the difference between the wafer butterfly valve and the flange butterfly valve, let’s take a look at the comparison of some characteristics of the wafer butterfly valve and the flange butterfly valve.

Wafer type butterfly valve with worm gear

The biggest difference is of course that the flanged butterfly valve has two more flanges, and the wafer type has two fewer flanges. Of course, the price is cheaper, and the price is about 2/3 of the flange. Flange butterfly valves are more reliable than wafer butterfly valves. Wafer butterfly valves are not as convenient as flanged butterfly valves in installation, because they need to be equipped with flanges, which can easily leak if they are not installed well.

From the perspective of specific working conditions, when selecting imported valves, use wafer-type butterfly valves as much as possible, which are light in weight and easy to replace. However, the length of the bolts of the wafer butterfly valve is longer, and the construction accuracy is higher. If the flanges on both sides are not aligned, the bolts will be subjected to greater pressure and the valve is prone to leakage. Under high temperature conditions, the bolts of the wafer butterfly valve may cause leakage after expansion, so if it is under high temperature conditions, the wafer butterfly valve is not suitable for large pipe diameters. In addition, wafer butterfly valves generally cannot be used at the end of the pipeline and downstream where it needs to be disassembled, because when the downstream flange is disassembled, the wafer valve will fall off. In this case, a short section must be made separately. For disassembly. The wafer butterfly valve has no flanges at both ends of the valve body, only a few guide bolt holes, and the valve is

Double flange butterfly valve (17)

connected with the flanges at both ends by a set of bolts/nuts. Compared with flanged butterfly valves, it is easier to disassemble. The cost of the valve is lower, but the disadvantage is that one sealing surface has a problem, and both sealing surfaces have to be disassembled. Regarding the blue butterfly valve, the above problem does not exist, and of course it has to pay a higher cost. But the cost will be higher.

The flange type butterfly valve has flanges at both ends of the valve body, which are connected with pipe flanges. The seal is relatively more reliable.
In addition to selecting the appropriate wafer butterfly valve or flange butterfly valve, attention should also be paid to the installation and maintenance of the butterfly valve. Because this is actually a place that can affect the selection of the valve outside of the specific purpose. Let’s take a look at the specific requirements below:
1. The valve disc stops at the closed position during installation.
2. Determine the opening position 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. Ask professionals to install according to the manufacturer’s instructions, especially the heavy butterfly valve should be fixed.
5. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When rotated to 90°, the butterfly valve is fully open.
The butterfly valve is used as a flow control, the main thing is to choose the size and type of the valve when purchasing. Butterfly valves are not only widely used in general industries such as petroleum, gas, chemical, and water treatment, but also used in cooling water systems of thermal power stations.

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

What are the characteristics of threaded gate valve in application

October 15, 2021

Commonly used pipeline connection methods are mainly: threaded connection, welding and flange connection. The threaded connection we mentioned today is actually also called threaded connection, which is also a connection

threaded gate valve-inner screw-wedge-EPDM (1)

method of gate valve, which connects the gate valve with the pipeline through internal and external threads.
Therefore, we can see that the types of threaded gate valves are divided into external thread type and internal thread type according to the thread position. According to the flow direction of the medium, there are straight-through type, direct-flow type and angle type. When the pipeline of the working condition is small-caliber and low-pressure, the threaded gate valve is generally used instead of the welded gate valve, so that the same cut-off effect can be achieved while saving the budget, and the cost performance is relatively high.
Below, let’s take a look at the specific characteristics of the threaded gate valve in the application?
(1) The flow resistance is small. The internal medium channel of the threaded gate valve is straight, the medium flows in a straight line, and the flow resistance is small.
(2) The threaded gate valve is more labor-saving whether it is opened or closed, because the medium pressure is not large.
(3) Water hammer is not easy to occur because it takes a long time to close.
(4) The threaded connection mode saves cost and is easy to install.
(5) The length of the structure is small, the shape is simple, and the scope of application is wide.
(6) The valve has good rigidity, smooth passage, small flow resistance, reliable sealing, light and flexible operation.
The threaded gate valve can be used for fully open and fully closed functions, and cannot be adjusted or throttled. Suitable for medium oil, water, steam, etc. For more details about the threaded gate valve, please contact our professional team to understand, we will be waiting for your inquiry 24 hours.

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

Introduction to the Features of Lever Wafer Butterfly Valve

October 9, 2021

Lever or Handle wafer butterfly valve is a kind of butterfly valve, usually with soft seal, which consists of a sealing surface made of rubber or fluoroplastic as a sealing material and a valve plate and stem made of carbon steel or

wafer-type-butterfly-valve-with-handle-13

stainless steel. Due to the limitation of the sealing surface material, the handle wafer butterfly valve is only suitable for water, gas, oil and other fluid media with a temperature of ≤80～120℃. The application fields include chemical industry, petroleum, electric power, textile, papermaking, construction water supply and drainage, etc. It is used for on-off control of normal temperature and pressure pipeline media on pipelines that transport various corrosive and non-corrosive fluid media in the engineering system, and can also be used for flow adjustment.
Handle wafer butterfly valves are generally only suitable for small-diameter valves, that is, valves with a diameter less than or equal to DN200mm. Because the small-diameter torque is relatively small, the opening and closing of the valve can be directly controlled by hand. The caliber is greater than 200mm, and according to the specific size of the caliber, it needs to be equipped with a turbine head, a pneumatic device or an electric device.
Because the handle wafer butterfly valve is a soft sealing butterfly valve, when the valve is installed and used, the valve must be opened at an angle, which is generally between 5°-10°. Do not allow the sealing surface rubber to be squeezed for a long time. state.
The main features of the handle wafer butterfly valve are:
1. The design structure is simple and unique, small in size, light in weight, and easy to operate.
2. Small-caliber operating torque is small, labor-saving and dexterous, opening and closing quickly.
3. It can be installed at any position of the pipeline, which is very convenient for installation and maintenance.
4. Handle wafer butterfly valves are usually soft-sealed, with reliable sealing performance, and can achieve two-way sealing with zero leakage.
5. The sealing surface material is easy to replace, resistant to aging, weak corrosion, and has a long service life.
Founded in 1994, Tanghai Valve is a professional valve manufacturer integrating design, development, production, sales, installation and service, and a high-quality valve manufacturer. The leading products include: wafer butterfly valves, flanged butterfly valves, hard-sealed butterfly valves, gate valves, butterfly check valves and other water series control valve products and related supporting pipeline accessories. The product sales range covers all parts of the country, and it has developed steadily in developing countries and regions such as Asia, Africa, and Latin America, and has successfully opened markets in developed countries and regions such as Europe and the United States. Products are widely used in water supply and drainage, electric power, petrochemical, metallurgical and other 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

What are the characteristics of the hard seal butterfly valve

September 22, 2021

Hard seal butterfly valve is a kind of butterfly valve with eccentric metal seal structure, and it is usually required to be installed horizontally in the pipeline. The sealing form of the metal hard seal butterfly valve is usually a metal-to-metal seal, and the sealing pair is composed of a metal hard material to a metal hard material. Hard-sealed butterfly valves can be driven by turbine manual, electric, pneumatic and so on.

triple offset butterfly valve-double flange- (5)

Nowadays, hard-sealed butterfly valves have been widely used in many fields such as petroleum, chemical industry, metallurgy, power generation, etc., to cut off or control the circulating medium in the pipeline system. At this stage, there is a relatively advanced hard-sealed butterfly valve, which is a triple-eccentric metal seated butterfly valve. Its body and seat are a conjoined component. On the sealing surface layer of the valve seat, a temperature-resistant and corrosion-resistant alloy material is surfacing welded. , And fix the multi-layer soft stacked sealing ring on the valve plate. The novel design allows the triple eccentric butterfly valve to overcome the shortcomings of poor sealing performance. The advantages of the triple eccentric butterfly valve are high temperature resistance, low friction when opening and closing, and when closed, the butterfly plate compensates for the seal along with the increase of the torque of the transmission mechanism, which greatly improves the sealing performance of the hard seal butterfly valve and prolongs the service life of the valve.

The advantages of the triple eccentric hard seal butterfly valve are:
1. The unique three-eccentric design enables frictionless transmission between the butterfly plate and the sealing surface of the valve body, reducing wear and extending the service life.
2. It can adapt well to low temperature, normal temperature and high temperature environment.
3. Pneumatic and electric devices can be configured according to the needs of users to meet the needs of remote control and program control.

The shortcomings of the triple eccentric hard seal butterfly valve are:
1. The butterfly plate of the hard sealing butterfly valve is fixed by multiple layers of soft and hard stacked sealing rings. When the butterfly plate is in the normally open state, the flowing medium will flush the sealing surface positively, which will affect the sealing performance of the valve over time.
2. Because the overall structure of the hard-sealed butterfly valve’s butterfly plate is too thick and the flow resistance is relatively large, the valve is not suitable for diameters below DN200.

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

Features of Stainless Steel Valves

September 15, 2021

Generally speaking, stainless steel valves are valves made of stainless steel. They are classified according to the stainless steel material grade of the valve body. They are mainly 301, 304, 316, 304L, 316L, etc. According to international standards, they can be divided into CF8, CF3, CF8M, CF3M, the quality of the material

D673H-16C-stainless steel pneumatic triple eccentric butterfly valve

CF8<CF3<CF8M<CF3M. Because stainless steel has strong corrosion resistance, is easy to form, has high compatibility, and can remain strong in a wide temperature range, many advantages make stainless steel valves widely used in heavy industry, light industry, daily necessities industry and architectural decoration industry. middle.
Stainless steel refers to steel that is resistant to corrosion by weak corrosive media such as air, steam, water and chemical corrosive media such as acids, alkalis, and salts. It is also called stainless acid-resistant steel. Stainless steel valves are also stainless acid-resistant steel valves. , And resistant to acid and alkali corrosion. Research tests have shown that the corrosion resistance of steel in weak media such as the atmosphere and water and oxidizing media such as nitric acid will increase with the increase of the chromium water content in the steel. When the chromium content reaches a certain percentage, the corrosion resistance of steel The sex changes, that is, from easy to rust to not easy to rust, from no corrosion resistance to corrosion resistance.
Common stainless steel valves mainly include stainless steel butterfly valves and stainless steel ball valves. The gate valve is rarely made of stainless steel, because the gate valve is usually used for low corrosive media such as water.
Stainless steel butterfly valve, also known as stainless steel flap valve, usually adopts three-eccentric metal hard sealing structure. The valve body, valve seat and butterfly plate sealing surface are all made of stainless steel with different hardness, which has strong corrosion resistance and long service life. It is widely used in metallurgical, electric power, petrochemical, water supply and drainage, municipal construction and other industrial pipelines with fluid pipeline medium temperature ≤ 425°C.
Stainless steel ball valves usually require horizontal installation in the pipeline. Stainless steel ball valves can be divided into stainless steel pneumatic ball valves, stainless steel electric ball valves, and stainless steel manual ball valves according to the driving mode. According to different stainless steel materials, it is divided into 304, 316, 321 stainless steel ball valves. The stainless steel ball valve switch is light and can also be made into a large diameter. It has reliable sealing, simple structure and convenient maintenance. The sealing surface and spherical surface are often in a closed state and are not easily eroded by the medium. It has applications in various 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

Characteristics of soft seal /resilient seated gate valves

September 7, 2021

Title: what are the characteristics of soft seal /resilient seated gate valves?

Traditional gate valves often have water leakage and corrosion. In order to overcome this shortcoming, the soft-seal gate valve appeared. As an updated product of the traditional gate valve, the soft-seal gate valve overcomes the shortcomings of poor sealing performance, poor elasticity, and easy corrosion of general gate valves.
The soft-seal gate valve uses a flexible rubber-wrapped gate, which uses the elastic energy of rubber to produce a small amount of deformation compensation, so that the valve can achieve a good sealing effect. The characteristics of the soft seal gate valve are as follows:

DIN-F5-BB-NRS-soft seated-wedge gate valve (10)

1. The gate is made of integral rubber
Use high-quality rubber to tightly wrap the gate of the soft-seal gate valve as a whole, which improves the sealing performance and is not easy to fall off.
2. The valve body is not easy to rust and corrosion resistant
The use of powder epoxy resin to coat the valve body of the soft-seal gate valve can effectively prevent the valve body from being oxidized, not easy to rust, and also prevent the valve body from being corroded. Soft-seal gate valves are often used in sewage treatment systems.
3. The valve seat is designed with a flat bottom
Traditional gate valves usually have a groove at the bottom of the valve seat. When the medium in the pipeline flows through the valve, impurities and particles contained in the medium will settle and silt in the bottom groove, which will make the valve unable to close tightly and cause leakage. Cause an accident. The bottom of the valve seat of the soft sealing gate valve is designed with a flat bottom and has no groove. After the medium in the pipeline flows through, there will be no siltation of impurities and particles, and the sealing performance of the valve is guaranteed to avoid leakage.
4. Precision casting valve body
The valve body of the soft sealing gate valve adopts precision casting, the size is accurate, and the inside of the valve body does not need to do any fine processing, and the sealing performance of the valve body is guaranteed.
5. Ductile iron valve body, light weight
The soft seal gate valve uses ductile iron as the valve body material. The overall weight of the valve is 20%-30% lighter than the traditional gate valve. The lighter weight makes the soft seal gate valve easier to install and maintain.
6. The inside of the valve body is not easy to be corroded
The valve body of the soft sealing gate valve is coated with non-toxic epoxy resin, and the gate is completely wrapped by rubber, which can effectively prevent the inside of the valve body from being corroded by the medium in the pipeline.
7. Three “O” seal ring seal design
The valve stem of the triple “O” seal ring seal design greatly reduces the friction resistance of the soft seal gate valve when it is closed, and the sealing performance is reliable, and no water leakage occurs; the unique design structure also makes the “O” seal ring It can be replaced under pressure and is maintenance-free.

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

Working principle and characteristics of triple eccentric butterfly valve

August 9, 2021

Triple eccentric butterfly valve, also named triple offset butterfly valve.

Nowadays, butterfly valves have been used in many industries. In the beginning, the butterfly valve was only used for the interception and communication of water media. The triple eccentric design enhances the function of the butterfly valve and has become one of the valves with excellent performance in industrial industrial pipeline equipment. The triple eccentric butterfly valve, as the name implies, is that three independent offsets are designed as valves. In reality, many people do not know which one is a triple-eccentric butterfly valve because of insufficient cognition. In this article, let’s talk about the working principle and characteristics of the triple-eccentric butterfly valve.

triple offset butterfly valve-double flange- (5)

The working principle of the triple eccentric butterfly valve is that the valve body of the butterfly valve has a horizontal valve port connected to the pipeline in structure, and the valve port has a valve plate. The shaft is perpendicular to the valve port and penetrates the valve body and the valve plate. The edge of the valve plate is provided with an outer spherical surface, and the valve port is provided with a sealing surface that can be matched with the outer spherical surface. When the sealing surface and the outer spherical surface are matched and sealed, there is an eccentric distance a between the sealing line and the axis of the shaft, which is in the transverse center of the valve plate. The line is the eccentricity b between the center line of the valve port and the center line of the shaft, and there is an angle β between the connection line of the outer spherical surface and the center line of the valve port. This is the principle of the triple eccentric butterfly valve.
The triple eccentric butterfly valve cleverly puts the triple eccentricity on the valve plate, and adopts a partial outer spherical structure on the outer edge of the valve plate. This structure needs to be completed on a CNC machine with a self-designed simple fixture. The outer eccentric spherical surface is polished to reach a roughness of Ra0.4, the spherical surface is chrome-plated or made of Stellite alloy, and the hardness reaches HRC45-60.
Put the eccentric angle on the valve plate, and press the valve seat on the valve body with a pressing ring, which solves the difficulties encountered in the processing of ordinary triple eccentric butterfly valves. The valve body, valve plate and valve seat cannot be exchanged for pairing. Repair after damage A series of problems such as high cost, all parts are modularized, warehouse management is simple, processing is simple, maintenance is convenient, and the cost of spare parts is reduced.
The butterfly valve is suitable for making large-diameter valves. It can be widely used in the cutting of petroleum transportation pipelines, metallurgical steel plants, gas main pipeline adjustment and cutting, chemical smelting equipment medium adjustment and cutting, water treatment equipment inlet and outlet adjustment and shutdown, and cooling water in thermal power stations. System, natural gas, lye, sea water, acid and other industries.

The characteristics of the triple eccentric butterfly valve are as follows:
1. Simple structure, light weight, composed of only a few parts. easy to use.
2. After the valve plate is fully opened, the thickness of the butterfly plate is the only resistance for the medium to pass through the valve body. The pressure is small and the flow can be better controlled.
3. When the valve plate is closed, the specific pressure between the outer spherical surface of the valve plate and the sealing surface of the valve seat is generated by the driving torque applied to the shaft. Coupled with the elastic compensation of the M-type elastic valve seat, the sealing performance of the valve can be enhanced, and the service life is greatly improved.
Understand the working principle and characteristics of triple eccentric butterfly valve, then where can I buy high-quality triple eccentric butterfly valve products? of course, 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

The sealing characteristics and principle of eccentric butterfly valve

July 26, 2021

Basic knowledge of eccentric butterfly valve: eccentric butterfly valve, also called offset butterfly valve; Eccentric butterfly valves can be divided into various types, generally single eccentric sealing butterfly valves, double eccentric sealing butterfly valves, and triple eccentric sealing butterfly valves.
Features of single eccentric sealing butterfly valve:
In order to solve the problem of squeezing between the butterfly plate and the valve seat of the concentric butterfly valve, a single eccentric butterfly valve was produced. Disperse and reduce the excessive squeezing between the upper and lower ends of the butterfly plate and the valve seat. However, because the single eccentric structure does not disappear during the entire opening and closing process of the valve, the scratching phenomenon between the butterfly plate and the valve seat has not disappeared, and the application range is similar to that of the concentric butterfly valve, so it is not used much.

Double eccentric-lug butterfly valve-D72F-150lbP-stainless steel (4)

The single eccentric sealing butterfly valve has the following characteristics:
1. It has a sealing structure with reliable performance and long service life.
2. It has a truss structure with small flow resistance, good rigidity and small pressure loss.
3. The valve plate sealing ring is easy to replace and easy to maintain.
4. The valve plate sealing ring adopts a “T”-shaped structure, and the sealing pair is linearly sealed.
5. The bottom end of the valve adopts bimetal thrust washer, which has excellent thrust performance.
6. The valve can be installed vertically or horizontally, with good applicability.
7. This type of valve is recommended to be used in one direction, and it can be used in two directions when the reverse sealing requirements are not strict.
8. When the valve is completely closed, the leakage of the seal test is zero.
9. Replace the valve plate sealing ring, O-ring, valve body, valve plate, shaft and other materials, which can be applied to a variety of media and different temperatures.
Features of double eccentric sealing butterfly valve:
On the basis of the single eccentric butterfly valve, the double eccentric butterfly valve is the most widely used double eccentric butterfly valve. Its structural feature is that the axis of the valve stem deviates from the center of the butterfly plate and the center of the body. The double eccentric effect enables the butterfly plate to be released from the valve seat immediately after the valve is opened, which greatly eliminates unnecessary excessive extrusion and scratching of the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and improves The life of the valve seat is improved. The scraping is greatly reduced, and at the same time, the double eccentric butterfly valve can also use a metal seat, which improves the application of the butterfly valve in the high temperature field. But because its sealing principle is a positional sealing structure, that is, the sealing surface of the butterfly plate and the valve seat is in line contact, and the elastic deformation caused by the butterfly plate squeezing the valve seat produces a sealing effect, so the closed position is very demanding (especially metal Valve seat), low pressure bearing capacity, which is why traditionally people think that butterfly valves are not resistant to high pressure and have large leakage.
The main features of the double eccentric butterfly valve are as follows:

1. Adopting full flow design, not affected by impurity jamming. The conjoined “O”-shaped sealing line at both ends makes the pipeline installation without gaskets and maintains a reliable seal. Different materials can be selected according to different usage requirements.
2. The butterfly plate material adopts streamlined design, which can be used in two directions, with low flow resistance and excellent flow characteristics.
3. The shaft pin adopts the unpinning structure, which can tightly combine the butterfly valve stems without weakening the strength of the shaft and has good interchangeability.
4. The valve body connection can be applied to ANSI125/150, DIN2501 PN10/16, JISB2210 10K, JIS G5527 7.5K standards.
Features of triple eccentric sealing butterfly valve:

triple offset butterfly valve-double flange- (4)

1. API specifications
2. Double safety structure
3. No dead zone design
4. Body valve seat structure
5. Thin layer valve seat structure
6. Replaceable seal pair
7. Balanced fixed structure
8. Intrinsic refractory structure
9. High sealing packing structure
The structural feature of the triple eccentric butterfly valve is that while the double eccentric valve stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the cylinder axis of the body, that is to say, after the third eccentricity, the butterfly plate seals The cross-section is no longer a true circle, but an ellipse, and the shape of the sealing surface is therefore asymmetrical. One side is inclined to the center line of the body, and the other side is parallel to the center line of the body. The biggest feature of this third eccentricity is that the sealing structure is fundamentally changed. It is no longer a positional seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely relies on the contact surface pressure of the valve seat to achieve the seal. Therefore, the problem of zero leakage of the metal valve seat is solved in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance is also solved. Since its inception, the triple eccentric butterfly valve itself has undergone a process of self-improvement and continuous development in order to meet the increasingly severe requirements of working conditions. Even if the highest zero leakage is required, the triple eccentric butterfly valve can theoretically be achieved, but in fact it still relies on careful design and precision manufacturing.
Related knowledge: features of eccentric butterfly valve; Installation instructions of double eccentric butterfly valve

Related products: Electric triple eccentric butterfly valve Pneumatic triple eccentric butterfly 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

bellows globe valve structure and features

July 9, 2021

Bellows globe valve structure (picture), the function and characteristics of bellows globe valve
Bellows globe valve structure:
Bellows cut-off valve is mainly filled with a bellows seal. The upper part of the outer surface of the bellows is welded to the valve body to form a closed space in which the liquid is contained. The valve stem is inserted into the bellows, and the bottom of the bellows is connected to the valve core. The expansion and contraction of the bellows controls the opening of the valve core. Therefore, if the bellows does not crack, there can be no leakage. The bellows has a very high sealing reliability and can be used in toxic media or gases. Such as chlorine. Prevent leakage.

Globe valve (9)

Structural characteristics of bellows globe valve:
1. Double sealing design (bellows + packing) If the bellows fails, the stem packing will also avoid leakage and meet international sealing standards
2. There is no fluid loss, reducing energy loss and improving plant equipment safety
3. Long service life, reduce maintenance times and lower operating costs
4. Rugged and durable bellows seal design to ensure zero leakage of the valve stem and provide maintenance-free conditions
5. The gas medium valve seat adopts PTFE soft sealing material to improve the sealing performance of this valve
6. High temperature resistance≤425℃The valve seat adopts conical hard seal. Achieve airtight performance and zero leakage

The function of the bellows globe valve:

The function of the bellows in the globe valve is to seal and prevent the medium from leaking from the valve stem. The lower end of the bellows and the valve stem are connected by sealing welding, the upper end and the gland are connected by sealing welding, and the gland is connected with the upper Metal spiral wound gaskets are generally installed between the flanges to ensure sealing. The bellows shut-off valve is extremely tight and rarely leaks.

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

The chemical composition, characteristics and applications of rubbers

December 30, 2020

Here we will introduce Rubber variety (abbreviated symbol) with their Chemical composition, Performance characteristics and Main application.

1. Natural rubber (NR) is mainly rubber hydrocarbon (polyisoprene), containing a small amount of protein, moisture, resin acid, sugar and inorganic salt. Large elasticity, high tensile strength, excellent tear resistance and electrical insulation, good wear resistance and drought resistance, good processability, easy to bond with other materials, and superior to most synthetic rubbers in comprehensive performance. Disadvantages are poor resistance to oxygen and ozone, easy to aging and deterioration; poor resistance to oil and solvents, low resistance to acid and alkali, and low heat resistance. Operating temperature range: about -60℃~+80℃. Production of tires, rubber shoes, hoses, tapes, insulation layers and sheaths of wires and cables, and other general products. It is especially suitable for manufacturing torsional vibration eliminators, engine shock absorbers, machine supports, rubber-metal

lug type butterfly valve-ductile iron

suspension components, diaphragms, and molded products.

2. Styrene butadiene rubber (SBR) is a copolymer of butadiene and styrene.
The performance is close to natural rubber, and it is currently the largest output of general-purpose synthetic rubber. It is characterized by abrasion resistance, aging resistance and heat resistance exceeding natural rubber, and its texture is more uniform than natural rubber. The disadvantages are: low elasticity, poor flex resistance and tear resistance; poor processing performance, especially poor self-adhesiveness and low green rubber strength. Operating temperature range: about -50℃~＋100℃.
Mainly used to replace natural rubber to make tires, rubber sheets, hoses, rubber shoes and other general products.

3. Butadiene rubber (BR)
It is a cis-structure rubber formed by polymerization of butadiene. The advantages are: excellent elasticity and wear resistance, good aging resistance, excellent low temperature resistance, low heat generation under dynamic load, and easy metal bonding. The disadvantages are low strength, poor tear resistance, poor processing performance and self-adhesiveness. Operating temperature range: about -60℃~＋100℃.
Generally used together with natural rubber or styrene-butadiene rubber, mainly to make tire treads, conveyor belts and special cold-resistant products.

4. Isoprene rubber (IR) is a kind of cis structure rubber made by polymerization of isoprene monomer. The che

Wafer butterfly valve-PN20-WCB-ANSI-150 (4)

mical composition and three-dimensional structure are similar to natural rubber, and the performance is very close to natural rubber, so it is called synthetic natural rubber. It has most of the advantages of natural rubber. Due to its aging resistance, natural rubber has slightly lower elasticity and strength than natural rubber, poor processing performance and higher cost. Operating temperature range: about -50℃~+100℃ It can replace natural rubber to make tires, rubber shoes, hoses, tapes and other general products.

5. Chloroprene rubber (CR) is a polymer formed by emulsion polymerization of chloroprene as monomer.
This kind of rubber contains chlorine atoms in its molecule, so compared with other general rubbers: it has excellent antioxidant, ozone resistance, non-flammable, self-extinguishing after fire, oil resistance, solvent resistance, acid and alkali resistance, aging and gas resistance. Advantages such as good tightness;
Its physical and mechanical properties are also better than natural rubber, so it can be used as general-purpose rubber as well as special rubber. The main disadvantages are poor cold resistance, large specific gravity, high relative cost, poor electrical insulation, and easy sticking, scorching, and mold sticking during processing. In addition, the raw rubber has poor stability and is not easy to store. Operating temperature range: about -45℃~＋100℃. It is mainly used to manufacture cable sheaths and various protective covers and protective covers that require high ozone resistance and high aging resistance; oil and chemical resistance hoses, tapes and chemical linings; flame-resistant rubber products for underground mining, and various moldings Products, sealing rings, gaskets, adhesives, etc.

6. Butyl rubber (IIR) is a copolymer of isobutylene and a small amount of isoprene or butadiene. The biggest feature is good air tightness, good ozone resistance, good aging resistance, high heat resistance, long-term working temperature can be below 130 ℃; resistance to strong inorganic acids (such as sulfuric acid, nitric acid, etc.) and general organic solvents, vibration absorption and damping characteristics Good and very good electrical insulation. The disadvantages are poor elasticity, poor processing performance, slow vulcanization speed, and poor adhesion and oil resistance. Operating temperature range: about -40℃~+120℃. Mainly used as inner tube, water tyre, balloon, wire and cable insulation layer, chemical equipment lining and shockproof products, heat-resistant conveyor belt, heat-resistant aging tape products.

7. Butadiene rubber (NBR) Copolymer of butadiene and acrylonitrile. It is characterized by its excellent resistance to gasoline and aliphatic hydrocarbon oils, second only to polysulfide rubber, acrylic ester and fluorine rubber, but better than other general rubbers. Good heat resistance, good air tightness, abrasion resistance and water resistance, and strong adhesion. The disadvantages are poor cold resistance and ozone resistance, low strength and elasticity, poor acid resistance, poor electrical insulation, and poor resistance to polar solvents. Operating temperature range: about -30℃~＋100℃. Mainly used to manufacture various oil-resistant products, such as hoses, sealing products, etc.

8. Hydrogenated butadiene rubber (HNBR) is a copolymer of butadiene and acrylonitrile. It is obtained by fully or partially hydrogenating the double bonds in the butadiene of NBR.
It is characterized by high mechanical strength and abrasion resistance, and its heat resistance is better than NBR when crosslinked with peroxide
Good, other properties are the same as nitrile rubber. The disadvantage is that the price is higher. Operating temperature range: about -30℃~+150℃. Mainly used for oil and high temperature resistant sealing products.

9. Ethylene propylene rubber (EPM\\EPDM)
The copolymer of ethylene and propylene is generally divided into two yuan ethylene propylene rubber and three yuan ethylene propylene rubber.
It is characterized by excellent ozone resistance, ultraviolet resistance, weather resistance and aging resistance, ranking first in general rubber. Electrical insulation, chemical resistance, impact elasticity, acid and alkali resistance, low specific gravity, high filling compounding is possible. Heat resistance up to 150°C, resistance to polar solvents-ketones, esters, etc., but not to aliphatic and aromatic hydrocarbons. Other physical and mechanical properties are slightly inferior to natural rubber and superior to styrene butadiene rubber. The disadvantage is that the self-adhesion and mutual adhesion are very poor, and it is not easy to bond. Operating temperature range: about -50℃~+150℃. Mainly used as chemical equipment lining, wire and cable sheathing, steam hose, heat-resistant conveyor belt, rubber products for automobiles and other industrial products.

10. Silicone rubber (Q)
It is a special rubber with silicon and oxygen atoms in the main chain, of which silicon element plays a major role. Its main feature is high temperature resistance (maximum 300℃) and low temperature resistance (minimum -100℃). It is currently the best high temperature resistant rubber. It has excellent electrical insulation and high stability to thermal oxidation and ozone. , Chemically inert. The disadvantage is that the mechanical strength is low, oil resistance, solvent resistance, acid and alkali resistance are poor, it is difficult to vulcanize, and the price is more expensive. Operating temperature: -60℃~+200℃.

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Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

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