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Difference between forged valve and cast valve

What is the difference between a forged valve and a cast valve? This article will explain to you how to distinguish between forged and cast valves.

PN40-DN100 cast steel WCB gate valve photo

PN40-DN100 cast steel WCB gate valve photo

forged valve:
Forged valves are forged and forged, and are generally used on high-grade pipelines with relatively small diameters, generally below DN50.
1. Forging: It is a processing method that uses a forging machine to apply pressure to a metal blank to cause plastic deformation to obtain a forging with certain mechanical properties, certain shape and size.
2. Forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper, etc. and their alloys. The original state of the material is bar, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of ​​the metal before deformation to the die cross-sectional area after deformation is called the forging ratio. Correct selection of forging ratio has a lot to do with improving product quality and reducing costs.

Cast valve:
Casting valves are valves made by casting. Generally, the pressure levels of cast valves are relatively low (such as PN16, PN25, PN40, but there are also high-pressure ones, which can reach 1500Lb, 2500Lb), and most of the calibers are above DN50.
1. Casting: It is the process of smelting metal into a liquid that meets certain requirements and pouring it into a mold. After cooling, solidification, and cleaning, a casting (part or blank) with predetermined shape, size and performance is obtained. The basic technology of modern machinery manufacturing industry.

forged ball valve-3pcs-high PN

forged ball valve-3pcs-high PN

2. The cost of the blank produced by casting is low, and it is more economical for parts with complex shapes, especially with complex inner cavities; at the same time, it has wide adaptability and good comprehensive mechanical properties.
3. Materials (such as metal, wood, fuel, molding materials, etc.) and equipment (such as metallurgical furnaces, sand mixers, molding machines, core making machines, shakeout machines, shot blasting machines, cast iron plates, etc.) required for foundry production ) more, and will produce dust, harmful gas and noise and pollute the environment.

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

Video of center-lined butterfly valve: https://youtu.be/NuSZH_AJcwY
Video of resilient seated gate valve: https://youtu.be/AI-LT1dy2sU
Related news/knowledge:
cast steel gate valve vs stainless steel gate valve
The difference between carbon steel and cast steel
Valve material and valve standards-(1)

Structure diagram of double eccentric butterfly valve

Double eccentric butterfly valves are often referred to as high performance butterfly valves. On the basis of the single eccentric butterfly valve, the most widely used double eccentric butterfly valve is further improved and formed.
Structural features of double eccentric butterfly valve: The center of rotation of the valve plate (ie the center of the valve shaft) forms a dimension α offset with the valve plate sealing section, and a dimension b offset with the centerline of the valve body.

double eccentric butterfly valve structure diagram

double eccentric butterfly valve structure diagram

Sealing principle of double eccentric butterfly valve: On the basis of the single eccentric sealing butterfly valve, the center of rotation of the valve plate (ie the center of the valve shaft) is offset by a dimension b with the center line of the valve body. When the double eccentric sealing butterfly valve is in a fully open state, The valve plate sealing surface will be completely separated from the valve seat sealing surface, and a gap y larger than the X gap in the single eccentric sealing butterfly valve is formed between the valve plate sealing surface and the valve seat sealing surface, thereby reducing the opening and closing of the valve plate. Mechanical wear and abrasion between the two sealing surfaces of the butterfly valve seal pair.

high performance-double eccentric-butterlfy valve-wafer-lug-flanged (6)

high performance-double eccentric-butterlfy valve-wafer-lug-flanged (6)

In the usual design, when the valve plate is rotated from 0° to 8° to 12°, the sealing surface of the valve plate can be completely separated from the sealing surface of the valve seat, so that during the opening and closing process of the butterfly valve, the sealing surface between the valve plate and the valve seat is separated. Compared with mechanical wear, the extrusion angle stroke is shorter, so that the mechanical wear and extrusion deformation are further reduced, and the sealing performance of the butterfly valve is further improved.

The main reasons for the failure of the sealing performance of the double eccentric butterfly valve sealing pair
① During the opening and closing process of the butterfly valve, when the valve plate rotates and squeezes the elastic soft valve seat, the valve plate and the valve seat are mechanically worn and scratched;
②After the valve plate squeezes the elastic valve seat, the elastic valve seat or the elastic layer of the valve plate will produce permanent plastic deformation, cold flow, elastic failure, etc.;
③The material of the elastic valve seat or the elastic layer of the valve plate is aging and failing, etc.;
④ Medium cavitation and erosion of the sealing surface.

Features of double eccentric butterfly valve
①The structure is more complicated than the single eccentric sealing butterfly valve, and the cost is slightly higher;
②The sealing performance is better than that of the single eccentric sealing butterfly valve;
③The service life is longer than that of the single eccentric sealing butterfly valve, and the operating pressure is also higher.
Difference: Double eccentric butterfly valve can use metal seat, which improves the application of butterfly valve in high temperature field. However, because its sealing principle is a positional sealing structure, that is, the sealing surface of the disc and the valve seat is in line contact, and the elastic deformation caused by the disc extrusion of the valve seat produces a sealing effect, so it has high requirements for the closing position (especially metal Valve seat), low pressure bearing capacity, which is why traditionally people think that butterfly valves are not resistant to high pressure and have large leakage.

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

Video of double eccentric butterfly valve:

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Information about stainless steel wafer butterfly valve

Stainless steel wafer butterfly valves are metal butterfly valves. Metal valves generally have a longer life than elastic sealing valves, but it is difficult to achieve a complete seal. The metal seal can adapt to higher working temperature, while the elastic seal has the defect of being limited by temperature.

The structure of stainless steel wafer butterfly valve

Double eccentric-wafer butterfly valve-D372F-150lbP-stainless steel (1)

Double eccentric-wafer butterfly valve-D372F-150lbP-stainless steel (1)

If the butterfly valve is required to be used as a flow control, the main thing is to correctly select the size and type of the valve. The structure principle of the butterfly valve is especially suitable for making large-diameter valves. Stainless steel wafer butterfly valves are not only widely used in general industries such as petroleum, gas, chemical, water treatment, etc., but also used in cooling water systems of thermal power stations. The commonly used wafer butterfly valve uses stud bolts to connect the valve between the two pipeline flanges. The flanged butterfly valve has a flange on the valve, and the two ends of the valve are flanged to the pipeline flange with bolts.

Installation of stainless steel wafer butterfly valve
The butterfly plate of the stainless steel wafer butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axial direction, and the rotation angle is between 0° and 90°. When the rotation reaches 90°, the valve is in a fully open state. The wafer butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. Moreover, it can be opened and closed quickly by rotating 90°, and the operation is simple. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance for the medium to flow through the valve body.

Classification of stainless steel wafer butterfly valves
According to the form, it can be divided into offset plate type, vertical plate type, inclined plate type and lever type. According to the sealing form, it can be divided into two types: soft sealing type and hard sealing type. The soft seal type generally uses a rubber ring seal, and the hard seal type generally uses a metal ring seal. According to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.

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
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

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What is a wafer type butterfly valve
Product Features of Electric Wafer Butterfly Valve
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How to prevent the motor of electric flange butterfly valve from overloading

The torque and axial force of the valve electric actuator are limited, so usually the valve electric device uses a torque-limiting coupling. Most of the torque type is three-jaw connection or key connection, and the valve electric device does not bear the axial thrust. Most of the thrust type is threaded connection, which can bear larger axial thrust. What determines the execution torque of an electric actuator? It is mainly determined by the specifications of the electric device. The overload operation of the electric flange butterfly valve motor is actually a manifestation of the working torque of the motor being higher than the control torque. The following several situations may cause the motor to run at an overload, which needs our attention.

Double flange butterfly valve (16)

Double flange butterfly valve (16)

1. When the power supply voltage is low and the required torque cannot be obtained, stop the motor;
2. Wrongly adjust the torque limit mechanism to make it larger than the stopping torque, causing continuous excessive torque and stopping the motor;
3. Using intermittently, the heat accumulation generated exceeds the allowable temperature rise value of the motor;
4. For some reason, the torque limit mechanism circuit breaks down, the torque is too large and the ambient temperature is too high, and the thermal capacity of the motor is relatively reduced, which may cause the motor to overload.
5. The motor model does not match the requirements of the electrical equipment, and the actual output torque does not have enough corresponding margin, which may cause damage to the motor during overload operation.
Generally speaking, there are two ways to protect the motor: one is to judge the increase or decrease of the input current of the motor; the other is to judge the heating of the motor itself. The basic protection method to prevent the motor from overloading is: using a thermostat to protect the motor from continuous operation or jog operation; using a thermal relay to protect the motor from stalling; using a fuse or overcurrent relay for short-circuit accidents. Most electrical equipment manufacturers connect the stroke and torque protection in series. When over-travel or over-torque, the micro switch cuts off the AC contactor coil control power in time, thereby cutting off the main circuit of the motor. Or there is a temperature control switch in the motor. When the valve motor is over-torque or running for a long time, the temperature of the motor rises. When the temperature exceeds the set temperature value, the temperature control switch immediately cuts off the control circuit to protect the motor.
During operation, the rotation direction of the handwheel of the electric device is always the same as the rotation direction of the output shaft, clockwise is to close the valve, and counterclockwise is to open the valve. If the actual rotation direction of the motor does not conform to the regulations, any two phases of the three-phase power supply need to be replaced. Otherwise, the protection measures will be ineffective and the motor will be damaged due to reverse phase.

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

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

Wafer type butterfly valve with worm gear

Wafer type butterfly valve with worm gear

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

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

Double flange butterfly valve (17)

Double flange butterfly valve (17)

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

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

TH Valve is a professional manufacturer of butterfly 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 is a wafer type butterfly valve
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Wafer type double disc swing check valve introduction

The correct operation method of manual valve

The manual valve is operated by the operator with the help of a handle or a hand wheel to manipulate the opening and closing of the valve by manpower. When the valve opening and closing torque is large, a turbine device needs to be installed between the handle or hand wheel and the valve stem, which is more labor-saving. . Normally, the switching direction of a manual valve is to pull the handle or handwheel of the valve, turn it clockwise in the thorium direction to close, and turn it counterclockwise to open the valve. However, under special circumstances, the opening and closing direction of the manual valve may be reversed. This requires operators, especially those experienced

Wafer type butterfly valve with worm gear

Wafer type butterfly valve with worm gear

operators, to not directly operate the valve based on experience, and check the valve before operation. Open and close signs to avoid losses caused by improper operation. The correct operation method of manual valve is as follows:
1. The operation of manual valve requires the person who manipulates the valve to hold the handle or hand wheel to operate. It is not possible to switch the valve with levers and long wrenches to avoid damage to the handle or hand wheel due to excessive force, let alone violent operation to avoid accidents. happen.
Under normal circumstances, the length of the handle or the diameter of the handwheel is less than 320mm, and only one person is allowed to operate; when the diameter of the handwheel is equal to or greater than 320mm, two people are allowed to complete the operation together, or a single person can appropriately use tools, levers or wrenches. Operate, but pay attention to the lever length not to exceed 0.5m.

manual valve installation site-method

manual valve installation site-method

2. Both manual gate valve and manual stop valve are operated with the help of handwheels. After the valve is fully opened or closed, it must be rotated 1/4 to 1/2 circle to make the threads tightly fit better and avoid the valve at the same time. Overtightening may cause damage.
3. To operate the manual steam valve, preheat the pipe before opening it to discharge the condensed water in the pipe; open the valve slowly to prevent the occurrence of water hammer and cause damage to the valve and pipeline equipment.
4. The sealing surface of the normally open manual valve is easy to stick to impurities and dirt. Before closing and closing, slightly open a slit to allow the high-speed flowing medium to wash away these foreign objects, and then gently close it to improve the sealing effect .
5. In some pipelines with over-temperature medium, when the manual valve is closed, the temperature in the valve body drops, because the thermal expansion and contraction cause the valve to shrink, and there will be some small gaps in the sealing surface, and the valve will leak. In this case, after closing the manual valve, close it again after a while.

The correctness of manual valve operation affects the service life of the valve and even production safety, so it is necessary to master the correct valve operation method. Safe production, start with small things.

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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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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Valve installation instructions and process precautions;
Valve actuator / actuation -(1)-introduction

How to choose a valve in the chemical industry

The media transported in various pipelines in the chemical industry are usually corrosive, such as sulfuric acid, hydrochloric acid, nitric acid and other corrosive media. All corrosion protection is the most basic requirement of chemical equipment. Chemical valves are of course no exception, and the selection of valve materials must be corrosion-resistant. If the chemical valve is wrongly selected, it will damage the equipment at the slightest level, or cause serious accidents, causing injury to machinery, equipment and even people. However, for different corrosive media, the selection of valves is also different. This article will talk about the key points of valve material selection for some common chemical media:

lug type butterfly valve, ductile iron, center lined,

lug type butterfly valve, ductile iron, center lined,

Hydrochloric acid: Most metal materials, including various stainless steel materials, are not resistant to hydrochloric acid corrosion, and high-silicon ferro-molybdenum can only be used in hydrochloric acid below 50°C and 30%. Contrary to metal materials, most non-metal materials have good corrosion resistance to hydrochloric acid, so rubber-lined valves (such as fluoroplastics, etc.) are the best choice for transporting hydrochloric acid. But if the temperature of the medium exceeds 150°C, or the pressure is greater than 16 kg, any plastics (including fluoroplastics and even polytetrafluoroethylene) will be difficult to handle. For hydrochloric acid exceeding this condition, there is no ideal valve currently on the market.

Sulfuric acid: As one of the strong corrosive media, sulfuric acid is an important industrial raw material with a wide range of uses. Different concentrations and temperatures of sulfuric acid have great differences in the corrosion of materials. For concentrated sulfuric acid with a concentration of more than 80% and a temperature of less than 80°C, carbon steel and cast iron have good corrosion resistance, but it is not suitable for high-speed flowing sulfuric acid. Not suitable for use as a valve material; ordinary stainless steels such as 304 and 316 have limited use for sulfuric acid media. Therefore, pump valves for transporting sulfuric acid are usually made of high-silicon cast iron (difficult to cast and process) and high-alloy stainless steel (20 alloy valve). Fluoroplastics have better resistance to sulfuric acid, and fluorine-lined valves (recommended by Tanghai Valves) are a more economical choice. If the pressure is too high and the temperature rises, the point of use of the plastic valve will be impacted, and you can only choose the more expensive ceramic ball valve.

Nitric acid: Most metals are rapidly corroded and destroyed in nitric acid. Stainless steel is the most widely used nitric acid resistant material. It has good corrosion resistance to all concentrations of nitric acid at room temperature. Note that stainless steel containing molybdenum (such as 316, The corrosion resistance of 316L) to nitric acid is not better than that of ordinary stainless steel (such as 304, 321), and sometimes even worse.

Acetic acid: Acetic acid is one of the most corrosive substances in organic acids. Ordinary steel will be severely corroded in acetic acid at all concentrations and temperatures. Stainless steel is an excellent acetic acid resistant material. 316 stainless steel containing molybdenum is also suitable for high temperature and rarefied materials. Acetic acid vapor. For demanding requirements such as high temperature and high concentration of acetic acid or other corrosive media, high alloy stainless steel or fluoroplastic pumps can be used.

Salt water/sea water: The corrosion rate of ordinary steel in sodium chloride solution, sea water and salt water is not very high, and generally must be protected by paint; all kinds of stainless steel also have a very low uniform corrosion rate, but may cause local corrosion due to chloride ions. It is usually better to use 316 stainless steel.

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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electric butterfly valve code naming method

Electric butterfly valve model preparation method, electric butterfly valve code naming method, only suitable in China.
With the increase in demand for valves in my country’s industrial manufacturing industry, electric butterfly valves have become a more prominent one among many valves. However, due to the wide variety of electric butterfly valves, and the difference in control modes and medium pressure and temperature, users often choose electric Uncertainty about butterfly valve models! In order to avoid such a situation, our company specially provides the electric butterfly valve model preparation instructions for your reference and understanding!

lug type butterfly valve, ductile iron, center lined,

lug type butterfly valve, ductile iron, center lined,

The electric butterfly valve model preparation instructions include the addition of additional conditions for the butterfly valve, the difference in connection methods, the upgrade of the transmission mode, the change of the structure, the level of valve pressure, and the requirements for temperature, pressure, corrosion and material. Hope It is helpful to everyone in the selection!
Model representation method of electric butterfly valve:
Additional codes for electric butterfly valves: BD thermal insulation butterfly valve, SD telescopic butterfly valve, TLD desulfurization butterfly valve, DH check butterfly valve, DKS fast butterfly valve, FDBD square louver butterfly valve;
The code of the butterfly valve: D represents the butterfly valve;
Transmission form code: manual (omitted), 3 means turbine drive, 6 means pneumatic drive, 7 means hydraulic, 9 means electric;
Connection code: 4 flange type, 6 welding, 7 pair clip type;
Code of structural form: 1 means centerline type, 2 means double eccentricity, 3 means triple eccentricity, 4 means variable eccentricity, 5 means single eccentricity;
Sealing material code: H stainless steel, X rubber, F polytetrafluoroethylene, FX composite rubber, M Monel alloy, Y cemented carbide, W valve body directly processed;
Pressure grade code: 10=PN1.0Mpa, 16=PN1.6, 25=PN2.5, 40=PN4.0, PN is the code of domestic pressure, MPA is the unit of pressure, one kilogram is equal to 0.1Mpa; Class150LB=1.6 mpa, 300LB=2.5-4.0mpa, Class is the American standard code, LB is the American standard pound unit.
Shell material code: C cast steel, P stainless steel 304, R stainless steel 316, AL special alloy steel, Z cast iron, Q ductile iron, N nylon. To
The above are common codes related to butterfly valves. For products that need to be customized due to special working conditions, they can be selected according to the design plan.
Electric butterfly valve model preparation instructions: D943H-16C Stainless steel electric flange hard-sealed butterfly valve

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

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

D: Represents butterfly valve;
9: Indicates that the transmission mode is electric;
4: The connection method is flange connection;
3: The structure is triple eccentric;
H: The sealing material is stainless steel;
16: Indicates that the nominal pressure is 1.6MPa;
P: Indicates that the valve body is made of stainless steel.
Related valve model: Pneumatic butterfly valve model Electric ball valve model Pneumatic ball valve model

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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Pneumatic butterfly valve model name coding method;
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Representation method of butterfly valve model