factory Archives

The Basic Knowledge of Butterfly Valves

September 6, 2021

Butterfly valve is also called butterfly type valve or flap valve, which is a kind of regulating valve with very simple structure. Its main structure is composed of valve body, butterfly plate, valve stem, valve seat, transmission device and operating mechanism.
How does the butterfly valve work?
The working principle of the butterfly valve is that a disc-shaped butterfly plate is used as the opening and closing part, which is connected with the valve stem and rotates with the valve stem around its own axis in the valve body to realize the opening and closing and adjustment of the pipeline. When the butterfly plate rotates 90° in the closed position, the valve is in a fully open state. At this time, the thickness of the butterfly plate is the only resistance to the flow of the medium, and the resistance is very small. In addition, changing the angle of the butterfly plate can be used to adjust the media flow. Butterfly valves are generally installed in the diameter direction of the pipeline and can be installed at any position.
The structural principle of the butterfly valve is very suitable for making large-diameter valves, which are used in general industries such as petroleum, gas, chemical industry, and water treatment. The most common fault in the use of butterfly valves is that the sealing surface rubber of the butterfly valve is corroded, worn and teared, aging or even falling off during long-term continuous use, which causes the valve to jam and cannot be closed normally, which affects the valve’s performance. Sealing performance. In order to solve this problem, the structure of the butterfly valve has been continuously optimized.
The simplest butterfly valve is the concentric butterfly valve, that is, the shaft center of the valve stem, the center of the butterfly plate, and the center of the body are in the same position. The structure of this kind of butterfly valve is very simple. The disadvantage is that the butterfly plate and the valve seat are severely squeezed and scratched, and the sealing surface wears quickly.
In order to make up for the shortcomings of the concentric butterfly valve, the single eccentric butterfly valve was born. The stem axis of the single eccentric butterfly valve deviated from the sealing center of the valve plate, so that the lower end of the butterfly plate is no longer the center of rotation, and the lower end of the butterfly plate and the valve seat are reduced. The pressure brought by the excessive squeeze.

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

The double eccentric butterfly valve is an improvement based on the single eccentric butterfly valve. The stem axis of the double eccentric butterfly valve deviates from the center of the seal and the center of the valve body. The advantage of the double eccentric butterfly valve is that the butterfly plate can be quickly separated from the valve seat after the valve is opened, which largely eliminates unnecessary squeezing and scratching between the butterfly plate and the valve seat, and also reduces the opening and closing of the valve. Resistance, wear and tear are reduced, and the life of the valve seat is improved.
All of the above valves have a shortcoming. They are all soft-sealed and cannot withstand high temperatures, but the use of high-temperature resistant metal materials to make butterfly valves has no guarantee of sealing performance. In order to solve this problem, a triple eccentric butterfly valve was developed.
The biggest feature of the triple eccentric butterfly valve is that it fundamentally changes the sealing structure of the butterfly valve. The triple eccentric butterfly valve is a torsion seal, not a position seal, that is to say, it no longer relies on the elastic deformation of the valve seat to seal, but completely relies on The contact surface pressure of the valve seat achieves the sealing effect. Therefore, the triple eccentric butterfly valve is resistant to high temperature, high pressure, and corrosion, but also has a good sealing effect.

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

Commonly used valves for Water Supply and Drainage System

September 2, 2021

Valves often used in water supply and drainage piping systems include butterfly valve, gate valve, check valve.
This article introduces common water supply and drainage system valves one by one.
1. Butterfly valve: a simple regulating valve, generally used in low-pressure medium pipelines for cutting off and intercepting. It is also one of the common valves in water supply and drainage piping systems. It regulates and intercepts the flow of water on the water supply and drainage pipeline. The butterfly valve is small in size, light in weight, easy to install and operate, but the opening and closing torque is relatively large.

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

The butterfly valve can be divided into wafer butterfly valve and flange butterfly valve according to the connection mode; according to the different driving mode, it can be divided into handle butterfly valve, turbine butterfly valve, electric butterfly valve, pneumatic butterfly valve, etc.
2. Gate valve: It can only be a kind of valve that can cut off the flow of the pipeline medium. The structure of the gate valve is more complicated. It can only be fully opened and fully closed. The opening and closing torque is small, the fluid resistance in the pipeline is small, and it can flow in both directions. The gate valve is most suitable for media that does not contain particles, such as water, because the sealing surface of the gate is easy to wear with impurities or particles in the medium. In addition, impurities precipitate to the bottom of the valve body, which will affect the sealing performance of the gate valve. Causes the defect that the valve is not closed tightly.

dual plate wafer type check valve (1)

The gate valve is only suitable for use in pipelines that need to be normally open or normally closed, because if the gate valve is frequently opened and closed, it may cause the valve plate to fall off and make the system lose its control ability.
The gate valve can be divided into parallel plate gate valve and wedge plate gate valve according to the difference of the gate. According to the difference of valve stem, it can be divided into open stem gate valve and dark stem gate valve.
3. Shut-off valve: similar to gate valve, the functions of the two are similar when the medium in the pipeline is cut off. But the difference between the globe valve and the gate valve is that the globe valve has a simpler structure and is more convenient to maintain, but the force used to switch the valve is greater than that of the gate valve. In addition, the globe valve is a one-way valve. When installing, pay attention to the valve body. The instructions on the operation must not be reversed.
4. Check valve: It is also a list valve and check valve, which has strict directio

AWWA C509-C515-resilient seated wedge gate valve-DN80-150lb (4)

nality and stipulates that the medium is only allowed to flow in one direction. The check valve is used in pipelines where the medium is water, and is mainly used to prevent backflow of water.
Commonly used check valves include butterfly check valves, muffler check valves, swing check valves and so on. When installing, according to the type of valve, determine whether to install on a vertical pipeline or a horizontal pipeline, and install it strictly in the direction marked by the arrow on the valve body, and the installation cannot be reversed.

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

Advantages and disadvantages of gate valve and its scope of application

September 1, 2021

This article will explain the advantages and disadvantages of gate valves and the scope of application. A gate valve is a valve in which the opening and closing part moves along the vertical direction of the pipeline channel axis. The

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

opening and closing part is called a gate, which is mainly used to cut off the flowing medium in the pipeline and can only be used fully open or fully closed. Therefore, the gate valve cannot be used as a regulating valve to regulate flow. Gate valves of different materials are adapted to different environments and temperatures, but gate valves are generally not used in pipelines that transport mud and other media, because these media contain impurities, which will affect the sealing effect of the gate.

Advantages of gate valve:
1. It can only be fully open and fully closed. When the gate is fully open, the resistance of the fluid through the valve is small;
2. The torque required for opening and closing is small and labor-saving;
3. It can be used in pipelines where the medium flows in both directions, and the flow direction of the medium is not restricted;
4. Compared with the shut-off valve, when the gate valve is fully opened, the degree of erosion and erosion of the sealing surface by the fluid medium is low;
5. Simple structure, convenient installation and use, and good manufacturing technology;
6. The overall structure length of the valve is relatively short.

Disadvantages of gate valve:
1. The overall dimensions and opening height are relatively large, which requires a large installation space;
2. When the gate is opened and closed, the friction with the sealing surface of the valve seat is large, causing certain wear on the sealing surface;
3. Usually the gate valve has two sealing surfaces, which is difficult to process and grind, and it is quite troublesome to maintain;
4. It takes a long time to open and close.

Gate valves usually have more applications in the following areas:
1. Oil and natural gas pipelines.
2. Transportation pipeline and storage equipment of refined oil.
3. Wellhead equipment for oil and natural gas exploitation.
4. City gas transmission pipeline.
5. Tap water and sewage treatment projects.

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

Commonly Used Seat Materials for Butterfly Valve

August 30, 2021

The valve seat is a detachable part inside the valve. Its main function is to support the valve core to be fully closed or fully closed, and to form a sealing pair. Under normal circumstances, the diameter of the valve seat is the size of the valve. The butterfly valve seat is made of a wide range of materials, but the commonly used materials include soft-seal EPDM, nitrile rubber (NBR), polytetrafluoroethylene (PTFE), and metal hard-seal hard alloy materials. kind. Let’s introduce them one by one below.

wafer type butterfly valve, EPDM seat (10)

1. EPDM: Compared with other general-purpose rubbers, EPDM has great advantages.
①The cost performance is very high. Among the commonly used rubbers, EPDM has the lightest raw rubber density and can be filled in a large amount, reducing the cost of the rubber.
②EPDM material is resistant to aging, sun exposure, heat resistance, moisture resistance, and radiation resistance, and is suitable for weak acid and weak alkali media. Good insulation properties.
③The applicable temperature range can be as low as -40℃–60℃, and it can be used for a long time under the temperature condition of 130℃.
2. Nitrile rubber (NBR): oil resistance, heat resistance, abrasion resistance and good water resistance, air tightness and excellent bonding properties. It is widely used in petroleum pipelines. The disadvantage is that it is not resistant to low temperature, ozone, poor insulation performance, and general elasticity.
3. Polytetrafluoroethylene (PTFE): A fluoroplastic, this material has strong resistance to acids, alkalis, and various organic solvents. At the same time, the material is resistant to high temperatures and can be used continuously at 260°C, and the maximum use temperature can reach 290-320°C. The emergence of PTFE has successfully solved many problems in the chemical, petroleum, pharmaceutical and other industries.

Fluorine lined butterfly valve-PTFE-WAFER (8)

4. Metal hard seal (hard alloy): The material of the metal hard seal valve seat has very good high temperature and high pressure resistance, corrosion resistance, wear resistance and other characteristics, which makes up for the defects of soft seal material that is not resistant to high temperature and high pressure. However, the hard seal material has high requirements on the processing technology. The only disadvantage of the metal hard seal valve seat is that the sealing performance is poor, and leakage will occur after a long time of operation.

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 commonly used valves

August 27, 2021

The valve is a pipeline accessory, used to open and close the pipeline and control the flow of fluid medium in the pipeline. The functions of the valve in the pipeline include cut-off, regulation, diversion, prevention of reverse flow, stabilization, diversion or overflow and pressure relief. There are many types of valves. As the control components of fluid control systems, from the simplest butterfly valves and gate valves to the various valves used in extremely complex automatic control systems, there are many varieties and specifications.

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

Valves can be used to control the flow of various types of fluids, such as air, water, steam, various corrosive media, mud, oil, liquid metal, and radioactive media. The application range covers various industries. Although there are many types of valves, what are the commonly used valves? This article introduces you one by one:

There are five types of commonly used valves: butterfly valves, gate valves, check valves, ball valves, and stop valves.

Butterfly valve:
The butterfly valve, also known as the flap valve, is a simple and easy-to-use regulating valve. The butterfly plate in the body of the butterfly valve is the closing part of the valve, which is in the shape of a disc. The working principle is that the butterfly plate rotates around the valve shaft to realize the valve. Open and close, usually, the butterfly plate is driven by the valve stem and rotates 90° to complete one opening and closing, and achieve the purpose of interception. If you change the deflection angle of the butterfly plate, it can also be used as a flow control. Under normal circumstances, butterfly valves are often used for on-off control of low-pressure pipeline media.
Wafer butterfly valve and flange butterfly valve are the two connection forms of butterfly valve. The butterfly valve is suitable for making large-diameter valves, suitable for natural gas, liquefied petroleum gas, city gas, cold and hot air, chemical smelting and power generation, environmental protection, building water supply and drainage, etc. It is used to regulate and cut off the flow of media on the pipelines that transport various corrosive and non-corrosive fluid media in the system.

gate valve:

non-rising-stem-gate-valve-IS&Y

Gate valves are usually used for interception in pipeline systems. Its opening and closing parts are gates. The movement direction of the gate is perpendicular to the direction of the medium flow in the pipeline. The gate rises and the valve opens to realize the flow of the pipeline medium; the gate falls, The valve is closed, and the flow of the pipeline medium is cut off. The gate valve can only be fully opened or fully closed to cut off the flow of the medium, and cannot be used for adjustment and throttling. Therefore, the gate valve is generally used to keep the gate valve gate plate fully open and fully closed, and is used in a pipeline environment that does not need to be opened and closed frequently.
According to the structure of the gate, the gate valve can be divided into two types: wedge gate valve and parallel gate valve. Wedge gate valves can be divided into three types: single gate valve, double gate valve and elastic gate valve.

Check valve:
The check valve is also a list valve or check valve, which is an automatic valve, which

double-wing-check-valve-3

means that the check valve works automatically and does not require manual operation. When the medium flows through the check valve, under the pressure impact of the fluid medium, the check valve The valve flap of the return valve opens automatically and the medium passes through; after the medium flow is cut off, the valve flap automatically closes under the force of its own spring device to prevent the medium from flowing back and backflow.
Check valves are only suitable for installation in pipelines where the medium flows in one direction. The main function is to prevent the medium from flowing backwards, to prevent the pump and drive motor from reversing, and to discharge the container medium.

Globe valve:
The globe valve, also known as the shut-off valve, is a forced-sealing valve. That is to say, unlike the automatic operation of a check valve, the shut-off valve must apply pressure to the disc when it is closed to force the sealing

globe valve body

surface to not leak. When the medium enters the valve from below the disc, the flow direction changes, so the resistance that needs to be overcome to close the shut-off valve is the friction between the valve stem and the packing, as well as the thrust generated by the pressure of the medium, and the force to close the valve. The force is larger than that of opening the valve, so the diameter of the valve stem should be larger, otherwise the valve stem will bend failure. The flow resistance of the stop valve is higher than other valves.
The shut-off valve can be used to cut off the medium like a gate valve, but more often, people use the shut-off valve to adjust the flow.

Ball valve:
The ball valve evolved from the rotary valve. It is the same as the butterfly valve in that it also needs to be rotated 90 degrees to open and close. The difference is that the butterfly

ball valve (8)

valve is a butterfly plate, and the cock of the ball valve is a sphere, with a circular through hole or channel passing through its axis.
The ball valve can cut off, distribute and change the flow direction of the medium in the pipeline, and only need to rotate 90 degrees and a small torque can be closed tightly. Therefore, the ball valve is most suitable for use as a switch and shut-off valve. At present, it has been widely used in petroleum refining, long-distance pipeline, chemical industry, papermaking 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

Precautions for installation and use of NRS gate valve

August 26, 2021

NRS gate valve means non-rising stem gate valve; RS gate valve means rising stem gate valve.

Gate valves can be divided into RS gate valves and NRS gate valves according to their appearance structure. This article mainly introduces the NRS gate valve. In the structure of the NRS gate valve, the stem nut is placed inside the valve body and fixed on the gate plate. Through the rotation of the valve stem, the valve stem nut drives the gate plate to move up and down to complete the opening and closing.

DN1000-DIN-F5-NRS gate valve-IS&Y (6)

The trapezoidal thread used in the drive of the concealed stem gate valve is located inside the valve body, so it is not affected by the external environment, but it is easily corroded by the medium circulating in the pipeline, and cannot be directly lubricated, which will damage the valve stem over time. Because the valve stem is located in the valve body, the opening degree of the concealed stem gate valve cannot be directly observed, and an indicator device is required.
The concealed stem gate valve requires a small operating space and is suitable for occasions with limited locations and dense pipelines, such as ships and underground pipelines. So what should be paid attention to during the installation and use of the concealed stem gate valve?
1. Before installation, you must carefully check the various standards of the concealed stem gate valve and whether the diameter meets the requirements for use; pay attention to the valve during transportation to avoid bumps. Before installing the concealed stem gate valve, remove the dirt in the valve body.
2. During installation, the concealed stem gate valve can be directly installed on the pipeline according to the connection method and installed according to the used position. Under normal circumstances, it can be installed at any position of the pipeline, but for future operation and maintenance considerations, choose an appropriate location for installation. The concealed stem gate valve should pay attention to the tightness during installation to prevent leakage and affect the normal operation of the pipeline.
3. The NRS gate valve should always be kept clean during use, and the transmission thread must be regularly lubricated. When a fault is found, it should be stopped immediately to find out the cause and clear the fault.
4. The concealed stem gate valve uses a hand wheel, do not use levers or other tools to avoid damaging the valve parts. Turn the handwheel clockwise to close, and vice versa to open. The dark stem gate valve should be used reasonably to ensure the correct use method and means.
5. The NRS gate valve stored for a long time should be checked regularly. The processing surface that is often

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

exposed should be kept clean, cleaned of dirt, and stored neatly in a ventilated and dry place indoors. It is strictly forbidden to stack or store in the open air.

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 taboos when installing valves

August 25, 2021

The valve is an important component in the fluid pipeline, and it is also a relatively fragile pipeline control device. Installing a valve is a technical task. It seems easy. In fact, there are many details to pay attention to. If there are some contraindications when installing the valve, it is serious. It will cause immeasurable consequences. This article will explain this problem to help you install valves safely and produce safely.

manual valve installation site-method

Taboos during valve installation
1. During winter construction, the valve shall be hydrostatically tested in a sub-zero temperature environment.
Possible consequences: due to the rapid freezing in the tube during the hydraulic test, the tube freezes.
The correct method: try to do a hydraulic test on the valve before the winter as soon as possible. After the pressure test, the water inside and outside the valve must be cleaned to prevent the valve from freezing and cracking in winter. If it is necessary to do a water pressure test in winter, it needs to be carried out indoors at a temperature above zero. Similarly, the water must be removed after the pressure test.

2. The sewage, rainwater, and condensate pipes for concealed installation are not subject to closed-water tests.
Possible consequences: Once there is a problem with the pipeline, it can not be found in time, and there will be water leakage, which will cause losses to the user.
The correct method: For concealed sewage, rainwater, condensate pipes, etc., closed water tests must be performed in strict accordance with the specifications to ensure that there is no leakage.

3. The flange of the butterfly valve can be replaced by the flange of the ordinary valve at will.
Possible consequences: Because the size of the flange of the butterfly valve is different from that of the ordinary valve, the disc of the butterfly valve is relatively large. If the inner diameter of the flange is too small, it will affect the opening and closing of the butterfly valve and cannot open normally , And eventually damage the valve. Measures: Correct method: Process and install the flange according to the actual size of the butterfly valve flange.

4. The valve installation method is wrong, for example, the installation direction is wrong, and the installation is not carried out in the direction indicated by the valve instruction.
Possible consequences: valve operation failure, difficult opening and closing, troublesome maintenance, leakage of valve body seal.
Correct method: When installing the valve, install it in strict accordance with the valve installation manual. After the installation is completed, check it against the manual.

5. The installed valves, specifications and models do not meet the design requirements.
Possible consequences: affect the normal use of the valve, or even damage the valve and cause losses.
The correct method: Before installing the valve, you must fully understand the working conditions and environment of the construction, and at the same time, you must be familiar with the application range of various valves, and select the valve model and specifications in strict accordance with the requirements of the working conditions.

6. Before installing the valve, the quality inspection of the valve was not carried out in accordance with the regulations.
Possible consequences: Failure to conduct quality inspection on valves, resulting in unqualified valves being installed on pipelines, increasing the possibility of pipeline leakage, and also increasing potential safety hazards in production.
Correct method: Before the valve is installed, the valve must be strictly inspected. The test should be 10% of the total number of valve products in each batch to ensure that the valve meets various national standards.

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

Cleaning /Purge method of triple eccentric butterfly valve

August 23, 2021

As a new type of high-performance butterfly valve product, triple eccentric butterfly valve is widely used in heating, heating, gas supply, water supply pipeline and heating system of power station. After the triple eccentric butterfly valve is installed on the pipeline, it must be purged before work. After the butterfly valve and the pipeline are

triple offset butterfly valve-double flange- (5)

installed, purging is required. The purging is to clean the pipeline and prevent the medium in the pipeline from affecting the normal operation of the valve. . What are the purge methods for the triple eccentric butterfly valve?

There are three common purging methods for triple eccentric butterfly valves: water flushing, air purging, and steam purging. Let’s introduce them one by one below.

Water flushing method:
1. Use clean water when flushing valves and pipes with water.
2. When flushing, use the maximum flow rate, and the flow rate of the water flow is not less than 1.5m/S.
3. The valve and the drainage branch of the pipeline must be flushed.
4. Water rinsing should be carried out continuously, until the color and transparency of the drain outlet are basically the same as the inlet water from the naked eye, it is qualified.
5. After the valves and pipelines have been flushed with water, if they are not put into production temporarily, the water inside should be completely drained to keep the valve body and pipeline dry.

Air purging method:
1. Air purging uses a large container in a large compressor to perform intermittent purging of valves and pipes. The purging pressure cannot exceed the design pressure of the vessel and pipeline.
2. When purging oil-free pipelines, the gas must not contain oil.
3. After air purging the pipeline, you can paste a white cloth or white painted wooden target board on the pipeline exhaust port where the valve is installed to check whether the pipeline is cleaned. After blowing for a few minutes, there is no rust on the white cloth. Other sundries such as dust are qualified.

Method of steam purging:
1. During steam purging, a temporary pipeline should be installed, which should be installed in accordance with the technical requirements of the steam pipeline.
2. The steam pipeline is used for purging the valves and pipelines with a large flow of steam, and the flow rate of the steam is not less than 30m/s.
3. Before steam purging, the pipes should be warmed up and the water in the valves and pipes should be drained. The pipes should be warmed up, drained in time, and the thermal displacement of the pipes should be checked.
4. The steam purging should be carried out in a cycle, and the sequence is heating-cooling-reheating.

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

Problems Existing in the Use of Triple Eccentric Butterfly Valves

August 20, 2021

The triple eccentric metal seated butterfly valve is a high-quality valve category with high reliability and a wide range of applications. The triple eccentric butterfly valve is composed of main components such as valve body, butterfly

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

plate, valve stem, multi-layer metal sealing ring, shaft seal and drive mechanism. Its advantages are solid structure, good sealing performance, small torque, easy automatic control, etc. The triple eccentric butterfly valve is suitable for a variety of demanding working conditions, and has a wide range of applications in petroleum refining, natural gas extraction, chemical industry, power stations, metallurgy, and urban heating. However, things have two sides, and there are many problems in the use of the three-eccentric metal seated butterfly valve.
1. The butterfly plate of the triple eccentric butterfly valve is fixed with multiple layers of soft and hard stacked sealing rings. When the butterfly plate is in the open state, the circulating medium will directly wash the sealing surface. The soft sealing material in the metal sheet sandwich is in the long-term wash of the medium. It will directly affect the sealing performance of the valve.
2. The triple eccentric butterfly valve is not suitable for valves with a diameter smaller than DN200 because of its own structural constraints, the entire butterfly plate is very heavy and the flow resistance is very large.
3. The sealing between the butterfly plate sealing surface and the valve seat of the triple eccentric butterfly valve is to press the butterfly plate against the valve seat by the torque of the transmission device. When the medium in the pipeline is in a state of positive flow, the higher the pressure of the medium, the tighter the sealing and squeezing. But when the medium in the pipeline flows back, the pressure of the medium may cause seal leakage.
In order to solve the problems existing in the use of the triple eccentric butterfly valve, a high-performance triple eccentric two-way metal seated butterfly valve was developed. For the two-way sealing triple eccentric butterfly valve, the seat sealing ring is composed of multiple layers of stainless steel sheets on both sides of the soft T-shaped sealing ring. The sealing surface of the butterfly plate and the valve seat is an oblique cone structure, and then a high temperature and corrosion resistant alloy material is surfacing on the sealing surface of the oblique cone structure, and the spring fixed between the pressure plate of the adjusting ring and the adjusting bolt of the pressure plate are assembled together .
This special structure effectively compensates for the elastic deformation between the shaft sleeve of the triple eccentric butterfly valve and the valve body, and perfectly solves the problem that the triple eccentric butterfly valve is prone to leakage during the two-way interchangeable medium delivery process. The soft T-shaped sealing ring composed of multilayer stainless steel sheets on both sides not only has the advantages of a metal seated material, but also has the characteristics of a soft sealing material. Therefore, the three-eccentric butterfly valve with two-way sealing is suitable for both low temperature and high temperature conditions. Under the conditions, it can maintain excellent sealing performance.

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 role of check valve and installation matters

August 19, 2021

The check valve is an automatic valve that relies on the pressure of the flow of the medium to achieve the opening and closing of the valve flap. The check valve is mainly used to prevent the medium from flowing back and backflow, so it is also called a check valve, a one-way valve and so on. Check valve is a kind of automatic valve, its function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, as well as the release of the container medium. This article will explain the function of the check valve and the precautions for installation.

The role of the check valve

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

The check valve is mainly used in the pump water supply system to prevent the impact of the high-pressure water backflow on the pump impeller. When the water pump in the water supply system of the water pump suddenly stops running, the pressure in the pump disappears instantly, and the high-pressure water connected to the outlet of the water pump will flow back to the water pump in the reverse direction. After the non-return valve installed at the outlet of the water pump has no medium pressure, it will be closed immediately to prevent the high-pressure water from flowing back to the pump in the reverse direction.
Imagine if there is no check valve installed at the outlet of the water pump, high-pressure water flows back to the water pump in the reverse direction, and the impeller of the water pump reverses under the impact of the high-pressure water. Under the impact of high-pressure water, the impeller may loosen or damage the impeller or other parts in a serious situation. When the pump runs again, the loose or damaged impeller can also fly out, bringing huge safety hazards to the production work.
The check valve in the hot water system is used to prevent hot water from flowing back into the pipeline. If the check valve is not installed, the hot water will flow back, which may scald the pipeline and even hurt people.

Precautions for check valve installation
1. The check valve is a one-way valve, so the installation position, height, and direction of inlet and outlet must meet the design requirements, and the direction of medium flow should be consistent with the direction of the arrow marked on the valve body.
2. Check the appearance before installing the check valve. The nameplate of the valve should meet the requirements of the current national standard “General Valve Marking” GB 12220. It can be used after all standards are qualified.
3. Do not allow the check valve in the pipeline to bear weight, especially the large check valve, which should have an independent support and not be affected by the pressure generated by the pipeline.

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

Posts

The Basic Knowledge of Butterfly Valves

Commonly used valves for Water Supply and Drainage System

Advantages and disadvantages of gate valve and its scope of application

Commonly Used Seat Materials for Butterfly Valve

What are the commonly used valves

Precautions for installation and use of NRS gate valve

What are the taboos when installing valves

Cleaning /Purge method of triple eccentric butterfly valve

Problems Existing in the Use of Triple Eccentric Butterfly Valves

The role of check valve and installation matters

TH VALVE • PROFESSIONAL VALVE MANUFACTURER

GET IN TOUCH WITH US