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Wafer type dual plate check valve: metal seated vs resilient seated

Wafer dual plate check valve is used for pure pipelines and industrial, environmental protection, water treatment, high-rise building water supply and drainage pipelines, to prevent the reverse flow of the medium. The check valve adopts a clamp type, the butterfly plate is two semicircles, and it adopts a spring for forced reset. The sealing surface can be built-up welding wear-resistant material or rubber lining, with a wide range of use and reliable sealing.

The check valve opening and closing parts are opened or closed automatically by the flow and force of the medium to prevent the medium from flowing back. The valve is called the check valve. Check valves belong to the category of automatic valves, which are mainly used in pipelines where the medium flows in one direction, and only allow the medium to flow in one direction to prevent accidents.

According to the structure of the check valve, it can be divided into three types: lift check valve, swing check valve and butterfly check valve. Lift check valves can be divided into two types: vertical and horizontal. Swing check valves are divided into three types: single valve, double valve and multi valve. The butterfly check valve is a straight-through type. The above-mentioned check valves can be divided into three types in connection form: threaded connection, flange connection and welding. A check valve is a valve that can automatically prevent fluid from flowing back. The disc of the check valve is opened under the action of fluid pressure, and the fluid flows from the inlet side to the outlet side. When the pressure on the inlet side is lower than that on the outlet side, the valve flap is

H46-double flanged dual plate check valve-metal seated

H46-double flanged dual plate check valve-metal seated

automatically closed under the action of the fluid pressure difference, its own

lug type dual plate check valve metal seated (3)

lug type dual plate check valve metal seated (3)

gravity and other factors to prevent the fluid from flowing back.

klug type dual plate check valve metal seated (1)The dual plate check valve is divided into flange dual plate check valve, lug dual plate check valve and wafer dual

plate check valve.

Classification of wafer dual plate check valves: hard-seal wafer dual plate check valve and soft-seal wafer dual plate check valve; of which soft-seal wafer check valve is divided into full-lined soft-seal wafer check valve and Semi-lined/normal soft-seal wafer dual plate check valve.

Features of Wafer dual plate Check Valve:

  1. Simple structure and light weight, especially suitable for low-pressure large-diameter pipelines;
  2. The paired clamp connection mode, the production process is simple, and the disassembly and assembly are convenient;
  3. The check valve adopts the clamp type, the butterfly plate is two semicircles, and the spring is forced to reset. The sealing surface can be built-up welding wear-resistant material or rubber lining, with a wide range of use and reliable sealing.

Model: H76X/H76H/H76W
Name: Wafer dual plate check valve
Please refer to the main technical parameters and spare parts materials:
https://www.tanghaivalve.com/wafer-type-double-disc-swing-check-valve-introduction/
Product name: Wafer double plate check valve (soft seal)
National Standard Number: H76X

dual plates check valve photos-normal sealing (1)

dual plates check valve photos-normal sealing (1)

Size range: DN40-DN1200
Pressure rating: PN10/16/25/40/64/100
Valve features: double valve plate design, short running track of the valve plate, spring load makes the valve plate close more quickly, effectively preventing water hammer
When the valve plate is opened, it is close to 90 degrees, and the pressure loss is small
Zero leakage
Size range: 2″ to 48″
Pressure range: 10bar-50 bar
Suitable flange: National standard or EN1092 PN10/PN16/PN25/PN40 or ANSI 125/150/300
Structure length: EN558 series 16, API594

Body material: gray cast iron, ductile iron, carbon steel, stainless steel, aluminum bronze
Valve plate material: ductile iron nickel-plated, stainless steel 201, stainless steel 304,

dual plates check valve photos- full rubber

dual plates check valve photos- full rubber

stainless steel 316, aluminum bronze
Valve seat material: nitrile NBR, EPDM, oil and acid and alkali resistant fluorine rubber VITON-A, steam resistant fluorine rubber VITON-B, hard seal
Uses: Suitable for installation at the outlet of high-lift pumps, or as a bottom valve in front of the pump, suitable for water, sea water, steam, oil, chemicals, chlorine, oxygen, and steam. Can be installed horizontally or vertically.
Application scope:
It is suitable for industrial, environmental protection, sewage treatment, high-rise building water supply and drainage pipelines, etc. It can also be used for environmental systems with corrosive media such as power plants and steel plants gypsum slurry.

 

Product name: Wafer double plate check valve (metal seated)
National standard number: H76H(W)-16C(16P, 16R, 16RL)
Size range: DN40-DN1200

H76-wafer type dual plate check valve metal seated

H76-wafer type dual plate check valve metal seated

Pressure rating: PN10/16/25/40/64/100
Temperature range: -20℃ -350℃
Body material: WCB, A105, CF8, CF3, CF8M.CF3M and other materials and special steel
Valve plate material: WCB, A105.2CR13, 304.304L.316.316L and other materials and special steel
Valve shaft material: A105.2CR13, 304.304L.316.316L and other materials and special steel
Valve seat material: 2CR13, 304.304L.316.316L, STL and other materials and special steel
Application range: water, steam, oil, nitric acid, acetic acid, strong oxidizing medium and urea and other media
More video for wafer dual plate check valve, please see below:
https://www.youtube.com/watch?v=pGrkznOd-JA
https://youtu.be/etwT8RX-S3Q
https://www.youtube.com/watch?v=XqRRI7o-LFI

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

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Maintenance Methods of Common Valves

Common valve failures include leakage, opening and closing parts damage and failure, etc. One of the most important reasons for the valve failure problem is that the valve is not well maintained. The valve is an important part of the pipeline transportation system. Maintenance and maintenance can make the valve better serve us. At the same time, it can also prevent valve failure from the source and reduce production accidents caused by valve failure. Therefore, this article will talk about the maintenance methods of commonly used valves.

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

1. For valves that are not in use for a long time, they must be cleaned regularly to remove dirt and dust on the exposed surface of the valve, and at the same time, they must be sealed to ensure that the inside of the valve is clean and dry. Store the valve neatly in a ventilated and dry place indoors, and it is strictly forbidden to stack it or store it in the open air. When storing, the butterfly valve is the easiest to store, just keep the butterfly plate in the closed state. For gate valves, globe valves and check valves, both ends of the passage should be blocked during storage, and the valve plate should be closed. The storage of the ball valve requires that both ends are blocked and in an open state.
2. Before installing the valve, you need to check the pressure and diameter of the valve again, and clean up the dirt on the valve during transportation.
3. When installing the valve, install the valve correctly according to the connection method of the valve. Generally, the commonly used valves can be installed at any position in the pipeline, but it is necessary to consider whether the operation of the operator is convenient after installation and whether it is convenient for future valve maintenance .
4. When the gate valve and ball valve are working, they are only used for fully open and fully closed. They cannot be used for flow adjustment, otherwise the sealing surface will be severely washed and corroded, and the opening and closing parts of the valve will be greatly worn.
5. When the handle valve and handwheel valve are opened or closed, levers, wrenches or other tools cannot be used to avoid damage to the valves.
6. Tighten the bolts on the valve packing gland evenly. Don’t beat the gland to make the gland tilt, which will damage or hinder the movement of the valve stem and cause valve leakage.
7. During use, the valve should be maintained regularly to keep the valve clean, and the transmission part should be regularly lubricated. Once the valve is found to be malfunctioning, it must be stopped immediately to find out the cause of the malfunction and clean up the malfunction.

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

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Commonly used valves for Water Supply and Drainage System

Valves often used in water supply and drainage piping systems include butterfly valvegate valvecheck 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

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)

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)

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 valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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What are the commonly used valves

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

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

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

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

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)

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 valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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What are the taboos when installing valves

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

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 valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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The role of check valve and installation matters

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

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 valvegate valvecheck valveglobe valveknife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

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Ways to Extend the Service Life of Valves

In industrial production, we always want to reduce costs, increase production capacity, and maximize profits. In addition to vigorously developing scientific and technological productivity, in daily work, paying attention to some small details, avoiding waste, can also reduce costs. Valves are disposable items and have their own service life. Once this period has passed, they must be replaced with new ones. Frequent replacement of valves will increase our production costs. Therefore, extending the service life of the valve can also maximize our production benefits. This article will start with the selection of the valve and tell us how to maximize the service life of the valve during the process of valve maintenance.

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

marine valve; butterfly valve; check valve; gate valve; manufacturer in China

Valve selection
Getting the best performance level of the valve is the first step in ensuring the life of the valve, so we have to make sure that the right valve is selected and used in the right place. In many cases, the main reason for valve leakage and failure is the wrong valve design or the wrong material of construction. Therefore, when selecting a valve, you must be clear about the parameters of the pipelined medium, use temperature, pressure, etc., and select the correct and appropriate valve according to the parameters.

Valve installation
After purchasing a suitable valve, pay special attention to the installation. On-site technicians may cause further damage to the valve when removing the valve end cover. When the end cover is removed, dust and foreign matter will be deposited in the valve, which may cause Damage to the ball and valve seat, and cause leakage once installed. So do not open the end cap without special reason.
Incorrect hoisting of pneumatic valves or electric valves will damage the actuators and valves. When transporting the valve on site, there is a lifting ring on the valve. Do not lift the valve or actuator through the valve stem. Therefore, during the installation phase, the most important step is to purge the pipeline before it is pressurized.

Valve maintenance
After the valve is installed, frequent maintenance is required to prevent the valve and drive equipment from malfunctioning. Every month, the valve in operation should be moisturized to optimize the performance of the valve.

Finally, there are some caveats:
1. Make sure that the start of the valve and the material list of valve control accessories conform to our specification sheet.
2. The valve packaging must be inspected to ensure that the exterior of the valve and components are intact during the transportation process, and all grease fittings are present.
3. Ensure that the valve process connection is covered to prevent dust and debris from entering the body cavity.
4. Pay attention to the valve manufacturer’s instructions for lifting and transporting the valve.
Tanghai Valve, a high-quality valve manufacturer, has better quality and longer service life. Escort your production work.

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

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The difference between internally and externally threaded valves

Threaded valve (also called  internal threaded valve) generally refers to a valve with internal or external thread on the valve body. It is mainly divided into internal threaded valve and external threaded valve. Corresponding to the pipeline. Usually threaded valves can only be manufactured with small diameters and are used for normal pressure or low pressure projects. If they are not available for high pressure work, they need to be used with welded link valves or flanged valves.

internally threaded valve and externally threaded valve

internally threaded valve and externally threaded valve

Common threaded valves are: threaded gate valve, threaded ball valve, threaded globe valve, threaded check valve.
The difference between internal threaded valve and external threaded valve:
From the point of use: Due to price and working flow requirements, most of the valves on the market use internal threaded valves. From the channel: Taking into account the thread connection, the passage of the external thread of the same caliber is smaller than the internal thread, the flow rate is faster, and the flow rate is small.
From the appearance: Most of the internal threads are pipe threads, the external threads are mostly taper threads, and the bite-type external threads are pipe threads.
In terms of pressure resistance: The wall of the valve with external thread of the same material is usually thicker than that of the internal thread (the smaller the passage, the thicker the wall), and the pressure resistance is greater. This is the reason why valves with high pressure ratings are all external threads. To
Sealing form of threaded valve:
1. Direct sealing: internal and external threads directly play a sealing role. In order to ensure that the joints are not leaking, they are often filled with lead oil, thread hemp and PTFE raw material tape; among them, PTFE raw material tape is widely used every day; this material has good corrosion resistance and extremely sealing effect. Good, it is convenient to use and store. When disassembling, it can be completely removed, because it is a non-sticky film, which is much better than lead oil and hemp.
2. Indirect sealing: the tightening force of the thread is transmitted to the gasket between the two planes, so that the gasket plays a sealing role.
Thread standard of threaded valve:
1. International standards ISO228/1, DIN259, are internal and external parallel threads, code G or PF (BSP.F);
2. German standard ISO7/1, DIN2999, BS21, taper external thread, parallel internal thread;
3. British standard ISO7/1, BS21, internal and external tapered thread, code PT or BSP.Tr or Rc;
4. American standard ANSIB21, internal and external tapered thread, code name NPT.

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

All types of check valve and its structures

Check valve refers to a valve whose opening and closing parts are circular discs and rely on its own weight and medium pressure to generate actions to block the back flow of the medium. It is an automatic valve, also known as one-way valve, non-return valve(NSV) or isolation valve. The movement of the disc is divided into lift type and swing type. The lift check valve is similar in structure to the shut-off valve, but lacks the valve stem that drives the disc. The medium flows in from the inlet end (lower side) and flows out from the outlet end (upper side). When the inlet pressure is greater than the sum of the weight of the disc and its flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows back. The swing check valve has a disc that is inclined and can rotate around the axis, and the working principle is similar to that of the lift check valve. The check valve is often used as the bottom valve of the pumping device to prevent the backflow of water. The combination of check valve and stop valve can play a role of safety isolation. The disadvantage is that the resistance is large and the sealing performance is poor when closed.

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

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

The working principle of the check valve:
Check valves can also be used to supply pipelines for auxiliary systems where the pressure may rise above the system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).

The function of this type of check valve is to only allow the medium to flow in one direction and prevent the flow in the opposite direction. Usually this kind of valve works automatically. Under the action of the fluid pressure flowing in one direction, the valve flap opens; when the fluid flows in the opposite direction, the fluid pressure and the self-coincidence of the valve flap act on the valve seat, thereby cutting off the flow.

Among them, the check valve belongs to this type of valve, which includes swing check valve and lift check valve. The swing check valve has a hinge mechanism and a valve disc like a door that rests freely on the inclined valve seat surface. In order to ensure that the valve clack can reach the proper position of the valve seat surface every time, the valve clack is designed in a hinge mechanism so that the valve clack has enough space for rotation and makes the valve clack truly and comprehensively contact the valve seat. The valve clack can be made of metal, leather, rubber, or synthetic covering can be inlaid on the metal, depending on the performance requirements. When the swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The valve disc of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except that the disc can be raised and lowered freely, the rest of the valve is like a shut-off valve. The fluid pressure lifts the disc from the seat sealing surface, and the backflow of the medium causes the disc to fall back onto the seat and cut off the flow. According to the conditions of use, the valve clack can be an all-metal structure, or it can be in the form of a rubber pad or a rubber ring inlaid on the valve clack frame. Like a shut-off valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow rate of the swing check valve is restricted. Rarely.
Classification of check valves:
The valve that opens or closes on its own by the force of the flow of the medium to prevent the medium from flowing back is called a check valve. Check valves belong to the category of automatic valves, which are mainly used in pipelines where the medium flows in one direction, and only allow the medium to flow in one direction to prevent accidents.

Classified by structure:
According to the structure, it can be divided into three types: lift check valve, swing check valve and butterfly check valve:

1. Lift check valves are divided into two types: vertical and horizontal.

2. The swing check valve is divided into three types: single, double and multiple.

3. The butterfly check valve is a straight-through type.

The above check valves can be divided into four types in connection form: threaded connection, flange connection, welding connection and wafer connection.

The selection criteria of the check valve are as follows:

1. In order to prevent the medium from flowing back, check valves should be installed on the equipment, devices and pipelines;

2. Check valves are generally suitable for clean media, not for media containing solid particles and high viscosity;

3. Generally, horizontal lift check valves should be used on horizontal pipes with a nominal diameter of 50mm;

4. The straight-through lift check valve can only be installed in horizontal pipelines;

5. For the inlet pipeline of the water pump, a bottom valve should be used. The bottom valve is generally only installed on the vertical pipeline at the inlet of the pump, and the medium flows from bottom to top;

6. Compared with the swing type, the lifting type has better sealing performance and greater fluid resistance. The horizontal type should be installed on the horizontal pipeline, and the vertical type on the vertical pipeline;

7. The installation position of the swing check valve is not restricted. It can be installed on a horizontal, vertical or inclined pipeline. If installed on a vertical pipeline, the flow direction of the medium should be from bottom to top;

8. The swing check valve should not be made into a small-diameter valve, it can be made into a high working pressure, the nominal pressure can reach 42MPa, and the nominal diameter can also be large, the maximum can reach more than 2000mm. According to the different materials of the shell and the sealing parts, it can be applied to any working medium and any working temperature range. The medium is water, steam, gas, corrosive medium, oil, medicine, etc. The working temperature range of the medium is between -196–800℃;

9. The applicable occasion for swing check valve is low pressure and large diameter, and the installation occasion is restricted;

10. The installation position of the butterfly check valve is not restricted. It can be installed on a horizontal pipeline, or on a vertical or inclined pipeline;

11. Diaphragm check valve is suitable for pipelines that are prone to water hammer. The diaphragm can eliminate the water hammer caused by the reverse flow of the medium. It is generally used on low-pressure and normal temperature pipelines, and is especially suitable for tap water pipelines. Normal media work The temperature is between -12-120℃, and the working pressure is less than 1.6MPa, but the diaphragm check valve can achieve a larger diameter, and the maximum DN can reach more than 2000mm;

12. The spherical check valve is suitable for medium and low pressure pipelines and can be made into a large diameter;

13. The shell material of the spherical check valve can be made of stainless steel, and the hollow sphere of the seal can be wrapped with polytetrafluoroethylene engineering plastic, so it can also be applied to the pipeline of general corrosive media, and the working temperature is -101–150 Between ℃, its nominal pressure is ≤4.0MPa, and the nominal passage range is between DN200-DN1200;

14. When selecting check valves for incompressible fluids, the required closing speed must be evaluated first, and the second step is to select the type of check valve that may meet the required closing speed;

15. The check valve for compressible fluid can be selected according to the similar method of check valve for incompressible fluid. If the medium flow range is large, the check valve for compressible fluid can be used A deceleration device, if the medium flow is stopped and started quickly and continuously, such as the outlet of the compressor, a lift check valve is used;

16. The corresponding size of the check valve should be determined, and the valve supplier must provide the data of the selected size, so that the valve size when the valve is fully opened at a given flow rate can be found;

17. For high and medium pressure check valves below DN50mm, vertical lift check valves and straight-through lift check valves should be used;

18. For low-pressure check valves below DN50mm, butterfly check valves, vertical lift check valves and diaphragm check valves should be used;

19. For high and medium pressure check valves with DN greater than 50mm and less than 600mm, swing check valves should be used;

20. For medium and low pressure check valves with DN greater than 200mm and less than 1200mm, wear-free spherical check valves should be used;

21. For low pressure check valves with DN greater than 50mm and less than 2000mm, butterfly check valves and diaphragm check valves should be used;

22. For pipelines that require relatively small water hammer impact or no water hammer when closed, slow-closing swing check valves and slow-closing butterfly check valves should be selected.

Types of check valves we produce:

We have other types of check valves: single-disc swing check valvedual plate check valve, tilting disc swing check valvelift swing check valvesilent check valve and ball check vlave 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 structure and connection of the American standard valve

American standard valves mainly have API and ASME standards. ASTM and ASTM are material standards; valves designed, manufactured, produced and tested according to American standards are called American standard valves.
The American standard valve is a control component in the fluid conveying system. It has the functions of cut-off, regulation, diversion, prevention of reverse flow, voltage stabilization, diversion or overflow and pressure relief; the valve used in the fluid control system is cut off from the simplest American standard. There are many types and specifications of American standard valves used in extremely complex automatic control systems. 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. Valve types: gate valve, knife gate valve, check valve, butterfly valve and others.

The structure types:

code structure type explaination standard face to face
C BB-BG-OS&Y bolted bonnet, bolted gland, outside screw & yoke API602/API602M ASME B16.10
D BB-BG-OS&Y bolted bonnet, bolted gland, outside screw & yoke API603/API603M ASME B16.10
E BB-BG-OS&Y-N bolted bonnet, bolted gland, outside screw & yoke-needle type API602M ASME B16.10
G BC-PISTON-LIFT (BOLTED BONNE,PISTON-LIFT) API602M ASME B16.10
H BC-PISTON-LIFT (BOLTED BONNE,PISTON-LIFT) outside screw & yoke API603M ASME B16.10
B BB-BG-OS&Y-W BOLTED BONNET,BOLTED GLAND,OS&Y ,BELLOWS SEAL TYPE) API600M ASME B16.10
L BB-BG-OS&Y-L BOLTED BONNET,BOLTEDGLAND ,OS&Y ,CRYOGENIC SERVICE SRRUCTURE ASME B16.34 ASME B16.10
1 BC-SWING (BOLTED BONNET,SWING) API600M ASME B16.10
2 PS-PISTON-LIFT (PRESSURE SEAL BONNET,PISTON-LIFT) API600M ASME B16.10
3 WAFER TYPE (WAFER CHECK VALVE) API594 API594
4 TILTING-DISC (TILTING-DISC TYPE CHECK VALVE) API600M ASME B16.10
5 BB-BG-OS&Y-F (BOLTED BONNET,BOLTED GLAND,OS&Y,WITH SPECCIAL PACKING) API600/API600M ASME B16.10
6 BB-BG-OS&Y (BOLTED BONNET,BOLTED GLAND,OS&Y) API600/API600M ASME B16.10
7 BB-BG-OS&Y-H (BOLTED BONNET,BOLTED GLAND,OS&Y,WITH   BLOMING HOLE) API600/API600M ASME B16.10
8 PS-BG-OS&Y (PRESSURE SEAL BONNET,BOLTED GLAND,OS&Y) API600/API600M ASME B16.10
9 PS-COVER SWING (PRESSURE SEAL BONNET, SWING) API600/API600M ASME B16.10
M BB-BG-M-SEAL PRESSURE SEAL BONNET,BOLTED GLAND,moving sealing API600M ASME 16.10

connection types:

code connection type explaination
S SW SOCKET WELDED
T NPT 60° Taper pipe thread/NATIONAL TAPER PIPE THREAD
G Rc 55° TAPER PIPE THREAD
R RF RAISED FACE
J RJ RING JOINT
W BW BUTT-WELDED
P PIPE EACH ENDWITH A 150mm SHORT PIPE
F MF(F) MALE-FEMALE FACE(FEMALE)
A RF-NPT one side RF, one side NPT

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China. It was founded in 2006. Its predecessor was Tanghai Valve Manufacturing Factory. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services.

Our products use advanced manufacturing technology, and strictly conform to API, DIN, BS, EN, ISO, GB and other international standards. The main products are butterfly valves, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…), etc. Our products are widely used in various fields such as marine industry, shipbuilding, petrochemical, metallurgy, water treatment, fire fighting, water supply and drainage, etc. The company has won unanimous recognition and praise from customers with high quality and good reputation.

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…)

URL: http://www.tanghaivalve.com

Name: Harry Li

Email: harry@tanghaivalve.com

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

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

Wafer butterfly valve-PN20-WCB-ANSI-150 (2)

Wafer butterfly valve-PN20-WCB-ANSI-150 (2)

Wafer butterfly valve-PN20-WCB-ANSI-150 (6)

Wafer butterfly valve-PN20-WCB-ANSI-150 (6)

Wafer butterfly valve-PN20-WCB-ANSI-150 (1)

Wafer butterfly valve-PN20-WCB-ANSI-150 (1)

rising stem gate valve-OS&Y

rising stem gate valve-OS&Y