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Structural Characteristics and application of Centerline Butterfly Valves

February 23, 2022

Centerline butterfly valve is one of the most common types of butterfly valves, mainly including centerline wafer butterfly valve and centerline flanged butterfly valve. In today’s article, we mainly talk about the structural characteristics and usage instructions of the centerline butterfly valve.

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

Structural characteristics of centerline butterfly valve
The composition of the centerline butterfly valve mainly includes the valve body, the butterfly plate, the valve stem, the valve seat and the actuator. The actuator mainly includes handle, turbine head, electric head, pneumatic head, etc. The valve body is made by integral casting process. The valve seat sealing ring is made of rubber and is inlaid on the valve body. A shaft sleeve is designed in the two shaft holes of the valve body to provide support and lubrication for the valve stem.
The operation of the centerline butterfly valve is also very simple. Take the handle centerline butterfly valve as an example. Pull the handle to rotate clockwise or counterclockwise, the handle drives the valve stem, and the valve stem drives the butterfly plate to rotate 90° to complete the opening and closing of the butterfly valve. The whole process is also very labor-saving.

Instructions for use of centerline butterfly valve
1. Avoid bumps and scratches during transportation;
2. Do not store in the open air during storage, avoid the valve from being exposed to sunlight or rain, pay attention to ensure the ventilation of the storage place, and keep the valve dry.
3. The following preparations should be done before installation of the centerline butterfly valve:
① Carefully check whether the valve used conforms to the performance specifications required by the operating conditions.
②Clean the sealing surface of the valve body without any impurities and dirt, and do not open or close the valve plate before cleaning.
③ Clean the inside of the pipeline to be installed, and there must be no dirt or debris.
④ Check whether the drive device can be used normally.
4. The installation position should be reasonable, and the installation position of the valve should be ensured to be convenient for use, maintenance or replacement. In addition, it is not necessary to consider the flow direction of the pipeline medium during installation.
5. Pipe flanges must use special flanges.
6. After the centerline butterfly valve is installed, it should be checked regularly during use. The main items to check are as follows:
① Whether the butterfly valve seat and O-ring seal are damaged or corroded.
②Whether the valve plate sealing surface is damaged or corroded.
Note: After each inspection, the inspection results should be recorded in detail for future reference.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve:

Introduction to the Characteristics and Uses of Centerline Wafer Butterfly Valves

February 21, 2022

Features of centerline wafer butterfly valve:
The centerline wafer butterfly valve can be divided into two categories according to the purpose and structure: sealed butterfly valve and non-sealed butterfly valve. Before understanding these two butterfly valve products, we need to have a general understanding of the characteristics of the butterfly valve.

JIS 10K-wafer butterfly valve-backup seat (4)

The name of the butterfly valve comes from the butterfly plate of the wing-like structure. Its operation mode is that the butterfly plate rotates 90° around the axis of the butterfly plate or the axis outside the butterfly plate in the cylindrical channel of the butterfly valve body to complete the opening and closing of the butterfly valve. The purpose of the midline wafer butterfly valve is to cut off and adjust in general industries such as petroleum, chemical industry, urban gas, urban heating, water treatment, etc. It is also used in the condenser and cooling water system of thermal power plants.
The sealing pair of the centerline wafer butterfly valve can be made of elastic materials such as rubber and fluoroplastic, and the soft seal butterfly valve is usually of the centerline type. For elastic sealing, the sealing ring can be embedded in the channel of the butterfly valve body or in the periphery of the butterfly plate. When used as a shut-off valve, the sealing performance of the soft-sealed midline butterfly valve can reach FCI70-2; 2006 (ASME B16-104) level VI, which is much better than the metal sealing pair. However, the soft-sealed midline wafer butterfly valve has a limitation, that is, the valve is not resistant to high temperature due to the influence of the material of the sealing pair, and there is a limit to the operating temperature.
Sealed centerline wafer butterfly valve and non-sealed centerline wafer butterfly valve:
1. Sealed midline wafer butterfly valve, this kind of butterfly valve can ensure complete sealing when closed, and can be used for cutting off in the pipeline. Seals are usually made of rubber and fluoroplastics. However, the eccentric metal-sealed butterfly valve and the blue-free butterfly valve that appear now can also achieve good sealing and two-way sealing.
2. The non-sealed midline wafer butterfly valve cannot guarantee absolute sealing when it is closed, but the leakage should still meet the ISO standard B, C, D grades, or meet FCI 70-2; 2006 (ASME B16.104) Class II,III,IV,V, this kind of butterfly valve is only suitable for use in pipelines for regulation or in pipelines with lax sealing requirements. The sealing material is usually metal.
The body form of the centerline wafer butterfly valve can be single flange type, no flange type or U-shaped section type. In the future, the technology of butterfly valve will also adapt to large diameter, high pressure and wide temperature range, so that the technology of butterfly valve will reach a higher level.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve:

What is the reason for the poor sealing of the valve

February 17, 2022

Where there is a pipeline, the valve is inseparable. The valve is installed on the pipeline and controls the flow of the fluid medium in the pipeline. It is an important control component. But the valve is also a wearable part. A common valve loss in our life is that the valve is not tightly sealed, resulting in leakage. So what is the reason for the poor

marine valve seat

sealing of the valve?
The leakage at the packing of the valve is a part of the valve that is prone to leakage failures. The valve is not tightly sealed, and the reasons are probably as follows.
1. Sealing auxiliary structure
Under the change of temperature or sealing force, the structure of the sealing pair will change. And this change will affect and change the force between the sealing pair, so that the performance of the valve sealing is reduced. Therefore, when choosing a seal, be sure to choose a seal with elastic deformation. At the same time, pay attention to the width of the sealing surface. The reason is that the contact surfaces of the sealing pair cannot be completely matched. When the width of the sealing surface increases, the force required for sealing is increased.
2. Specific pressure of sealing surface
The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the specific pressure of the sealing surface is also a very important factor. Under the same conditions, too high specific pressure will cause valve damage, but too low specific pressure will cause valve leakage. Therefore, we need to fully consider the appropriateness of the specific pressure when designing
3. Physical properties of the medium
The physical properties of the medium also affect the valve sealing performance. These physical properties include temperature, viscosity, and hydrophilicity of the surface, among others. The temperature change not only affects the slackness of the sealing pair and the change of the size of the parts, but also has an inseparable relationship with the viscosity of the gas. Gas viscosity increases or decreases with increasing or decreasing temperature. Therefore, in order to reduce the influence of temperature on the sealing performance of the valve, when designing the sealing pair, we should design it as a valve with thermal compensation such as an elastic valve seat. Viscosity is related to the permeability of the fluid. When under the same conditions, the higher the viscosity, the lower the permeability of the fluid. The hydrophilicity of the surface means that when there is a film on the metal surface, the film should be removed. Because of this very thin oil film, it will destroy the hydrophilicity of the surface, resulting in blockage of fluid channels.
4. The quality of the sealing pair
The quality of the sealing pair mainly means that we must check the selection, matching and manufacturing accuracy of materials. For example, the valve disc fits well with the valve seat sealing surface, which can improve the sealing performance. The characteristic of many circumferential waviness is that its labyrinth sealing performance is good.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve:

Knife Gate Valve Structure and Working Principle

February 16, 2022

Knife gate valve, also called knife type gate valve, is a kind of gate valve. The structural feature of the knife gate valve is that there is an oblique cut at the bottom of its valve plate. Like a knife edge, this knife-shaped oblique cut can easily cut off the medium circulating in the pipeline, so that the valve can be closed without being blocked by the medium. Below is the structure diagram of the knife gate valve.

Knife gate valve (6)

Knife gate valves are generally used in medium pipelines such as pulp, slag, coal ash, sewage, and chemical raw materials. They can only be fully opened and fully closed. They are used as shut-off valves and cannot be used for flow regulation. The transmission modes of the knife gate valve are manual, pneumatic, electric, etc., and its working principle is also very simple. The following takes the manual knife gate valve as an example to introduce the working principle of the knife gate valve to you.
The working principle of the manual knife gate valve is to turn the handwheel by hand to make the valve stem rise or fall, thereby driving the gate to move up and down to achieve the purpose of opening or closing the valve. Turn the handwheel clockwise, the gate goes down, and the valve closes. Turn the handwheel counterclockwise, the gate rises, and the valve opens.
Compared with the traditional gate valve, the structure of the knife gate valve is simpler, the length and size are smaller, and it is easier to install, disassemble and maintain. Knife gate valves are suitable for use in medium pipelines with high consistency and solid particles. The gate like a guillotine has a better gate breaking effect, and can effectively cut off various impurities contained in the medium in the pipeline, completely solving the leakage phenomenon of the traditional gate valve after passing through the medium containing particulate impurities.
Knife gate valves have very short structural lengths and take up little space. The full-bore knife gate valve design allows the valve to be used in dirty media, and the replaceable seat and packing also make valve maintenance easier.
Although the performance of the knife gate valve is better than that of the traditional gate valve, the price of the knife gate valve is higher than that of the traditional gate valve, so the knife gate valve cannot completely replace the traditional gate valve at present.

Knife gate valve installation and use:
1. Before installation, check the valve cavity and sealing surface, and do not allow dirt or sand to adhere;
2. The bolts of each connecting part should be tightened evenly;
3. Check that the packing parts are required to be pressed tightly, not only to ensure the sealing of the packing, but also to ensure the flexible opening of the gate;
4. Before installing the valve, the user must check the valve model, connection size and pay attention to the flow direction of the medium to ensure the consistency with the valve requirements;
5. When installing the valve, the user must reserve the necessary space for the valve drive;
6. The wiring of the drive device must be carried out according to the circuit diagram;
7. The knife gate valve must be maintained regularly, and must not be collided and squeezed at will, so as not to affect the sealing.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of knife gate valve:

Sealing Surface Structure of Handle Wafer Type Butterfly Valve

February 14, 2022

The sealing surface structure of the handle wafer butterfly valve is the key to ensure the reliable sealing of the valve and an important basis for judging the performance of the valve. The sealing performance is related to whether the butterfly valve can perform normal adjustment and cut off the medium work. In general, the sealing surface is

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

composed of the valve seat and the disc of the wafer butterfly valve. It depends on the close contact between the valve seat and two or more precision-machined and ground sealing surfaces on the disc, or the sealing surface is produced by pressure. The sealing is achieved by plastic deformation.

The sealing surface of the handle wafer butterfly valve:
1. Resistant to medium corrosion;
2. Wear resistance and friction;
3. Ensure reliable sealing under the current working conditions;
4. Good processing technology;
5. Easy to assemble and maintain.

The sealing surface form of the handle wafer butterfly valve:
The sealing surface of the valve has several forms, including flat seal, cone seal, spherical seal, and knife seal. The handle wafer butterfly valve is mainly flat seal and spherical seal. The concept of flat seal is that the two contact surfaces of the seal are flat. Compared with several other sealing forms, the flat seal has its own unique advantages, the most important being the convenience of processing and repair. If it is used on the globe valve, it can also make the valve open and close without friction at the moment. Spherical seal means that one of the two contact surfaces of the seal is spherical. Butterfly valves with good sealing performance, ball valves and some small-diameter globe valves are used more. The advantage of the spherical seal is that the seal is larger and the sealing performance is good, but the disadvantage is that the maintenance is more difficult.
There are many fastening forms for the sealing surface of the handle wafer butterfly valve, which are mainly determined according to the conditions of the medium used, such as the pressure, temperature, corrosiveness of the medium, and the properties of the material of the sealing ring and the material of the housing. The basic requirements for the tightening of the valve sealing ring are that the joint surface has good sealing, easy processing, convenient maintenance, reliable connection and durability.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve:

What is the principle of triple eccentric butterfly valve

February 11, 2022

Triple eccentric butterfly valve is a kind of butterfly valve with outstanding performance in industrial pipelines. According to the sealing form, triple eccentric butterfly valve belongs to the category of hard sealing butterfly valve. Therefore, the triple eccentric butterfly valve has the characteristics of a hard-sealed butterfly valve, which is

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

resistant to high temperature, erosion, and has a long service life. And because the triple eccentric butterfly valve directly welds the high temperature corrosion resistant alloy material on the valve seat surface, the valve also has the same excellent sealing performance as the soft sealing butterfly valve. So what is the principle of triple eccentric butterfly valve? What are the three eccentricities of the triple eccentricity? Why use a triple eccentric structure?

The sealing surface of the triple eccentric butterfly valve is an inclined conical surface. The valve seat of the valve body is in contact with the sealing ring of the butterfly plate. Its working principle is to drive the movement of the butterfly plate by operating the transmission device. During the movement of the butterfly plate, its sealing The ring is in full contact with the valve seat because of the elastic deformation to achieve the seal.
A prominent feature of the triple eccentric butterfly valve is that the sealing structure of the valve is changed. It is no longer a traditional position seal, but a torsion seal, that is to say, it does not rely on the elastic deformation of the valve seat to achieve sealing, but relies on the sealing surface of the butterfly plate. The contact surface pressure with the valve

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

seat is used to achieve the sealing effect, which also solves the problem of large leakage of the metal valve seat, and because the contact surface pressure is proportional to the medium pressure, the triple eccentric butterfly valve has a strong high pressure and high temperature resistance.

Three eccentric butterfly valve three eccentric
The first eccentricity: the deviation from the plane of the sealing surface to the centerline of the valve stem;
The second eccentricity: the distance from the centerline of the valve body to the centerline of the stem;
The third eccentricity: there is an included angle between the center line of the cone surface where the sealing surface of the valve body is located and the center line of the valve body channel.

Reasons for using triple eccentric structure
The use of triple eccentric structure can reduce the friction between the sealing surface of the disc and the sealing surface of the valve body when opening or closing, so that the disc can quickly disengage or release the valve seat when the triple eccentric butterfly valve is opened or closed, reducing the operation time. torque, the operation is more labor-saving and light, and the service life of the sealing surface of the butterfly valve is increased.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of triple eccentric butterfly valve:

Properties of triple eccentric butterfly valve

February 10, 2022

Performance advantages of triple eccentric butterfly valve:
1. It integrates adjustment and cut-off, and has strong controllability.
The design of the new triple eccentric butterfly valve adopts a double safety structure. In order to prevent the deformation of the disc, the dislocation of the valve stem, and the occlusion of the sealing surface caused by the

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

influence of fluid pressure and temperature, two independent stoppers are installed on the upper and lower sides of the disc. The push ring ensures the normal operation of the valve under any working conditions; in order to prevent the valve stem from being damaged and flying out and causing unexpected accidents, independent valve stem flying-out prevention mechanisms are designed at the lower end of the valve inside and outside.
2. No dead zone design, small opening torque.
The shape of the valve plate of the triple eccentric butterfly valve is an elliptical cone, and its surface is surfacing with hard alloy, which has excellent wear resistance. The floating U-shaped stainless steel valve seat has the function of automatically adjusting the center. When the valve is opened, the valve plate of the elliptical cone sealing surface is first separated from the U-shaped elastic valve seat, and then rotated; when the valve is closed, the valve plate rotates, and the valve plate automatically adjusts the center to the elastic valve seat under the action of the eccentric shaft. Seat pressure deforms the seat until the seat is in close contact with the oval conical sealing surface of the valve plate. When the valve is switched on and off, the disc does not scratch the valve seat, the torque of the valve stem is directly transmitted to the sealing surface through the disc, and the opening torque is small, thus eliminating the common jumping phenomenon when opening the valve, that is, eradicating the dead zone (no sense band) . This design without dead zone enables the triple eccentric butterfly valve to enter the controllable area almost from 0 opening to 90 opening, and its control ratio can be as high as 1001 or more, which is twice that of ordinary butterfly valves.
3. Zero leakage, high temperature and high pressure resistance.
The biggest feature of triple eccentricity is that it fundamentally changes the sealing structure. It is no longer a position 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 sealing effect. This sealing structure enables the triple eccentric butterfly valve to achieve a hard seal of level VI and achieve true zero leakage. At the same time, due to the selection of the metal valve seat and the structural characteristics of the face seal, the problem of high temperature and high pressure resistance is also easily solved. In addition, the triple eccentric butterfly valve adopts the body seat structure, which makes the valve structure more compact, and reduces the chance of the valve seat directly contacting the medium, reduces the degree of erosion of the valve seat, and can effectively prevent small solids in the medium. The impact of the material and thermal expansion may cause the sealing surface to bite, thereby extending the service life of the valve seat. The new triple eccentric butterfly valve can not only replace the body seat, but also the disc sealing surface and disc are independent, and the disc sealing surface can also be replaced, which greatly reduces the maintenance cost.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of triple eccentric butterfly valve:

introduction of micro-resistance slow-closing butterfly check valve

January 25, 2022

Introduction of Micro-resistance Slow-closing Butterfly Check Valve
The structure of the butterfly check valve is very simple, and its structural length is also very short compared to other check valves. Butterfly check valve is also called butterfly check valve. The connection method is wafer type. The

micro resistance butterfly check valve (3)

valve plate is two semicircular butterfly plates. The two butterfly plates are connected by the valve stem and are forced to reset by spring. The working principle of the butterfly check valve is: when the medium flows through the valve body channel, the medium pressure is greater than the force of the spring, and the two discs are pushed open, the valve is opened, and the medium flows; when the medium stops flowing, the two discs Then due to the force of the spring, the valve is forced to reset, and the valve is closed, and the backflow of the medium is prevented at the same time.
Butterfly check valve is also known as double-clip check valve. Its sealing surface can be surfacing wear-resistant material or lined with rubber. It has a wide range of use and reliable sealing. Butterfly check valves are automatic valves and do not require manual operation. This type of valve is usually used in pure pipelines, as well as pipelines in the fields of industry, environmental protection, water treatment, and high-rise building water supply and drainage, to prevent the backflow of the medium. To prevent the reverse flow of the medium.
The main code is HH46 HH48 HH49
Micro-resistance slow-closing butterfly check valve application
It is mainly used in the supply and drainage pipelines of purified water, source water, sewage, seawater and other media. It is installed at the outlet of the pump to cut off the backflow of the medium to eliminate destructive water hammer, protect the pipeline and make the pump run safely.
Features of Micro-resistance Slow-closing Butterfly Check Valve

micro resistance butterfly check valve (4)

1. Small in size, light in weight, and only about one-third of the length of the swing check valve, it is more suitable for use in pipelines with limited space.
2. The slow closing system has excellent performance, long-term movement does not fail, can effectively control the slow closing of the valve disc, and can eliminate the destructive water hammer.
3. Rubber soft seal, good sealing performance, wear resistance, long service life and better stability. .
4. There is a closing spring on the valve disc, which opens and closes smoothly, without vibration and noise.
5. The flow channel is usually small in fluid resistance, sensitive in opening and closing of the valve plate, and good in sealing performance.
6. Compared with other check valves, the flow resistance is smaller, and it has obvious energy saving effect.

Micro-resistance slow-closing butterfly check valve main parts and materials

Part Name	Material
valve body	Gray cast iron, carbon steel, ductile iron, stainless steel
Disc	Cast steel, ductile iron, stainless steel
stem, spring	Stainless steel
Slow closing device, micro-control valve	Stainless steel

Main technical parameters of micro-resistance slow-closing butterfly check valve

Nominal pressure (Mpa)	Shell test pressure (MPa)	Sealing test pressure (MPa)	proper temperature	Applicable media	Slow closing time
1	1.5	1.1	≤80℃	clean water, sewage, sea water	3-60 seconds
1.6	2.4	1.76
2.5	3.75	2.75

Product structure diagram of micro-resistance slow-closing butterfly check valve

structure diagram of micro resistance butterfly check valve

The main connection dimensions of some products of the micro-resistance slow-closing butterfly check valve (unit: mm)

main dimensions-sizes of micro resistance butterfly check valve

Working principle of micro-resistance slow-closing butterfly check valve

This check valve is mainly composed of a valve body, two semicircular discs, a return spring, an oil storage cylinder, a slow-closing small cylinder group, and a needle valve (micro-adjustment valve). Relying on the thrust of the imported medium, the two valve discs are pushed open smoothly. At the same time, the imported pressure medium enters the lower part of the piston in the oil cylinder, pushes the piston, and presses the oil on the upper part of the piston into the tail end of the small cylinder on both sides of the valve body through the needle valve, so that the piston rod in the small cylinder extends. When the inlet medium pressure drops below the outlet pressure, the medium will flow back, and the valve flap will automatically close under the action of the spring and the medium backflow. However, since the piston rod is in the extended position, it cannot be fully closed against the valve disc, and there is still about 20% of the area left for the medium to pass through, thus eliminating the water hammer. The valve disc is divided into two steps by the piston to quickly close first and then slowly to close, which can not only prevent the motor from reversing, but also play the role of eliminating mute.

Installation of Micro-resistance Slow-closing Butterfly Check Valve

1. The check valve can be installed horizontally (the arrow is parallel to the horizontal ground), or it can be installed vertically (the arrow is vertical to the horizontal ground).
2. Before installation, the pipeline should be cleaned, and the valve should be fully inspected to ensure that it is not damaged and then loaded into the pipeline. When loading, pay attention to the direction of the arrow and the running direction of the medium.
3. A filter should be installed at the inlet of the valve. A butterfly valve or gate valve should be installed at the outlet to facilitate the maintenance of the valve and other equipment.
4. When tightening the flange connecting bolts, attention should be paid to the symmetry, uniformity and firmness.
5. For a check valve with a working pressure greater than 1.0 MPa, the strength and tightness test should be carried out before installation, and it can be used only after passing the test. During the strength test, the test pressure is 1.5 times the nominal pressure, and the duration is not less than 5 minutes. The valve housing and packing should be qualified without leakage. During the tightness test, the test pressure is 1.1 times the nominal pressure; the duration of the test meets the requirements of GB 50243.
6. The check valve cannot bear the weight in the pipeline, and the large check valve should be supported independently so that it will not be affected by the pressure generated by the pipeline system.

Operation and debugging of micro-resistance slow-closing butterfly check valve

1. Initial test debugging
Close the needle valve on the oil reservoir clockwise, then open it counterclockwise for 3-5 turns.

2. Operation adjustment
After starting the water pump, observe whether there is oil leakage or water leakage at each connection of the slow-closing system. At the same time, use a wrench to loosen the screw plug on the needle valve body by one or two turns, so that the air in the slow-closing system can be discharged, and then quickly tighten the screw plug until there is leakage. When the pipeline pressure rises to a certain pressure, stop the pump and observe, there may be two situations at this time:

(1) The seal does not die when closed, and the motor reaches the speed of rotation faster. The reason for this phenomenon is that the opening of the needle valve is too small, and the pressure oil in the small cylinder does not return to the oil storage cylinder in a short time, so that the valve disc cannot be closed for a long time. At this point, just turn the needle valve counterclockwise half a turn to one turn.

(2) The seal is closed quickly, and the pipeline produces a great vibration sound. There are two reasons for this phenomenon: A) Because the opening of the needle valve is too large, the oil in the small cylinder quickly returns to the oil storage cylinder, that is, the valve disc is quickly closed to produce water hammer. At this time, try to close the small needle valve clockwise. If the small needle valve is closed and the pump is turned on for the second time, there is still a loud vibration when the pump is stopped again, which belongs to the reason B. B) The piston in the small cylinder does not extend. Check whether the needle valve is open, gently loosen the oil pipe joint at the small cylinder, and observe whether there is oil coming out. If there is oil leakage, it is proved that the oil circuit is unblocked. At this time, it may be because the oil in the oil storage is not enough, please refuel urgently. Refueling method: Disassemble the oil pipe joints on both sides of the needle valve, remove the needle valve counterclockwise with a wrench, insert a steel rod with a diameter of about 12mm and a length of about 300mm into the oil cylinder, and use a hammer to gently press the oil cylinder into the oil cylinder. The piston is knocked into the bottom end, at this time, add 20# oil to the oil cylinder, then install the needle valve, and then connect the copper pipe.
After the operation is adjusted, there is no need to move all parts, and it will work automatically and normally in the future.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve: https://youtu.be/NuSZH_AJcwY
Video of double eccentric butterfly valve: https://youtu.be/yOw2xp3bIaE
Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0
Video of dual plate wafer check valve: https://youtu.be/XqRRI7o-LFI
Video of knife gate valve: https://youtu.be/vFSbTF_FGXM
Video of PTFE butterfly valve: https://youtu.be/Lutith_TJD0
Video of resilient seated gate valve: https://youtu.be/AI-LT1dy2sU

Types and Models of Butterfly Valves

January 24, 2022

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

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

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

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

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve: https://youtu.be/NuSZH_AJcwY
Video of double eccentric butterfly valve: https://youtu.be/yOw2xp3bIaE
Video of triple eccentric butterfly valve: https://youtu.be/AkRwg2X1Wh0
Video of PTFE butterfly valve: https://youtu.be/Lutith_TJD0

Advantages and Disadvantages of Triple Eccentric Butterfly Valves

January 21, 2022

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

triple eccentric butterfly valve-

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

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

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

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

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of triple eccentric butterfly valve:

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