News Archives

Difference between forged valve and cast valve

April 8, 2022

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

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

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

Video of center-lined butterfly valve: https://youtu.be/NuSZH_AJcwY
Video of 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 triple eccentric butterfly valve

March 24, 2022

With the advancement of science and technology and the improvement of production technology, the industrial requirements for butterfly valves are no longer simple cut-off and adjustment of normal temperature and low pressure media, but also require butterfly valves to play a role in high temperature and high pressure environments. For this reason, the triple eccentric butterfly valve was born, and has replaced the application of some gate valves, globe valves, ball valves and other valves in the industry. What is the structure of the triple eccentric butterfly valve? What are the structural characteristics of the triple eccentric butterfly valve?

Triple eccentric butterfly valve structure

triple eccentric butterfly valve structure diagram

The triple eccentric butterfly valve is a hard-sealed butterfly valve. This kind of butterfly valve adopts the triple eccentric sealing structure and has the characteristics of compact structure, fast opening and closing speed, labor-saving and light operation, and reliable sealing performance. It is suitable for pipelines under various working conditions. media flow. Three eccentric butterfly valves are currently widely used in electric power, metallurgy, petroleum, chemical industry, urban heating and other industries.

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

1. The shape of the sealing surface of the valve body and the butterfly plate is an elliptical cone, and the center line of the sealing cone surface of the valve body and the butterfly plate has an eccentric angle c° with the center line of the valve body channel.
2. There is an axial eccentricity a between the center line of the valve body and the disc sealing surface and the valve stem shaft.
3. There is a radial eccentricity b between the center line of the valve stem and the center line of the valve body.

Triple eccentric butterfly valve sealing principle
On the basis of the double eccentric sealing butterfly valve, the center line of the valve seat and the center line of the valve body form a β angle offset. When the triple eccentric sealing butterfly valve is in a fully open state, the sealing surface of the valve plate will be completely separated from the sealing surface of the valve seat. , and the same gap y as the double eccentric sealing butterfly valve is formed between the sealing surface of the valve plate and the sealing surface of the valve seat. When the valve plate of this type of butterfly valve is opened from 0° to 90°, the sealing surface of the valve plate will be separated from the sealing surface of the valve seat at the moment of opening. When it is closed at 90° to 0°, only at the moment of closing, the sealing surface of the valve plate will contact and press the sealing surface of the valve seat.

This is the three eccentricities of the triple eccentric butterfly valve. So what are the characteristics of the triple eccentric butterfly valve structure?
1. The unique triple eccentric design, the friction coefficient between the valve body and the sealing surface of the disc is extremely small, which reduces the wear of the sealing surface and prolongs the service life of the valve.
2. The eccentric design reduces the opening and closing torque of the valve, and the opening and closing is more rapid.
3. The valve body and the disc are directly conical, as shown in the figure above, when the disc is closed, the medium exerts pressure on the disc. The conical design makes the valve more tightly closed, realizing automatic sealing and greatly improving Improve the sealing performance and truly achieve zero leakage.
4. It can be equipped with different driving methods according to customer needs or working conditions, such as installing pneumatic and electric actuators to realize automatic operation of triple eccentric butterfly valves.
5. The sealing ring on the butterfly plate is made of stainless steel sheet and flexible graphite. It has the rigidity of metal and the elasticity of non-metal, and also makes the triple eccentric butterfly valve have the advantages of metal hard sealing and elastic sealing at the same time. Good sealing performance can be achieved in low temperature environment or high temperature working condition.

If you want to know more about triple eccentric metal hard sealing butterfly valve, please pay more attention to the official website of “Tanghai Valve”. If you have the needs of this valve, you are also welcome to inquire.

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

Video of triple eccentric butterfly valve:

How to install wafer butterfly valve and installation tips

March 11, 2022

Title: How to install wafer butterfly valve

In this article, let’s talk about the installation method of the wafer butterfly valve. Wafer type is a connection method of butterfly valve, that is, when installing on the pipeline, it is necessary to clamp the butterfly valve with two pieces of flanges, and then connect it with the flange on the pipeline. Corresponding to it is another connection method of butterfly valve, flange type. The installation of flanged butterfly valve will be shared with you in the future. Today we mainly talk about how to install the wafer butterfly valve in the form of pictures and texts.

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

The structure of the wafer butterfly valve is relatively short and takes up little space. During installation, use the special flange for the wafer butterfly valve to fix it, and then put the fixed wafer flange into the middle of the flanges at both ends of the pipeline, and use bolts to fix it. The control of the fluid medium in the pipeline can be realized by fixing it through the special flange of the wafer butterfly valve and the pipeline flange (if there is no flange on the pipeline, the special flange for the butterfly valve needs to be welded on the pipeline). The wafer type butterfly valve occupies a small space, which makes it especially suitable for installation and use in situations where the space is narrow or the distance between pipes is relatively small.
The specific installation steps of the wafer butterfly valve are as follows:
1. Place the wafer butterfly valve between the two pre-installed special flanges for wafer butterfly valves, and pay attention to align the flange bolt holes with the round holes of the butterfly valve body.

2. Insert the bolts and nuts into the flange holes to connect the valve body and the flange, and correct the flatness in the method, but be careful not to overtighten the bolts and nuts.

3. Weld the flange on the pipe, this step should be done by spot welding.

4. Remove the wafer butterfly valve first.

5. Weld the two flanges on the pipe completely to complete the fixation.

6. After the weld between the flange and the pipe is cooled, install the wafer butterfly valve. At this time, pay attention to opening the butterfly plate a little.

7. Correct the installation position of the butterfly valve again, and tighten the bolts, but be careful not to over-tighten them.

8. Fully open the butterfly plate of the butterfly valve to ensure that the butterfly plate of the butterfly valve can be opened and closed freely.

9. Cross the bolts again and tighten them evenly;

10. After the above steps are completed, test the opening and closing of the butterfly valve again to ensure that the valve can open and close freely.

The above is the introduction of butterfly valve installation steps. Here, I would like to tell all friends who purchase butterfly valves. Before installing the wafer butterfly valve, pay attention to the handling and do not bump it at will. After installation, non-professionals should not disassemble it casually.

Double offset-wafer butterfly valve-D72F-150lbC (1)

Manual wafer butterfly valve installation skills

1. Storage work before installation: Store the manual wafer butterfly valve in a cool, dry and ventilated environment, and cover the valve to prevent the valve from being contaminated with dust and all debris.
2. Before the wafer butterfly valve is installed on the pipeline, the pipeline needs to be calibrated, and the positions of the pipes at both ends cannot be deviated. Body strain or rupture.
3. Before the valve is installed, the valve and all installed pipelines should be cleaned again to ensure that the inside of the valve and the pipeline is completely clean, and no dust is left.
4. Manual wafer butterfly valve belongs to manual butterfly valve, which requires frequent manual operation. Therefore, there are also requirements for the installation position of the manual butterfly valve. The installation position of the valve must be convenient for personnel to operate and maintain in the future. It has been demonstrated that the best position for manual valve installation is about 1.2 meters from the operating floor. For valves installed outdoors, cover the valve with some covering to prevent bad weather from affecting the valve.
5. When installing on the pipeline, make sure that the butterfly plate is in a closed state, so as to avoid collision and damage between the butterfly plate and the pipeline flange, which will affect the sealing performance.
6. After the manual wafer butterfly valve is installed, if there is an opening and closing failure during use, it is necessary to find out the cause and eliminate the failure. It cannot be forced to open and close by beating, prying or brute force.
The above is the whole content of the “manual wafer butterfly valve installation skills” introduced for you. Here, the editor also reminds everyone that after the valve is installed, it must be regularly maintained during the use of the valve. work, so as to ensure the normal and smooth operation of the valve. If you have purchase requirements for manual wafer butterfly valves, you are welcome to consult the official website of Tanghai Valve.

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

Video of center-lined butterfly valve:

Video of double eccentric butterfly valve:

Advantages of the handle butterfly valve of Tanghai valve manufacturer

March 8, 2022

What are the advantages of handle butterfly valve? To understand this, let’s first understand the handle butterfly valve. The handle butterfly valve is a kind of manual butterfly valve. The common materials for making the handle butterfly valve are gray cast iron, ductile iron, cast steel, stainless steel, etc. The handle butterfly valve is the most common pipeline accessory in the pipeline system. It is generally required to be installed horizontally, and the

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

butterfly plate of the handle butterfly valve is installed in the diameter direction of the pipeline. The switch operation is also very simple and convenient. Rotate the handle, the handle drives the valve stem to rotate, and the circular butterfly plate rotates around the valve stem. Usually, it is turned on by turning counterclockwise, and turned off by turning clockwise. The rotation angle is 0°-90°. Between °, when the disc rotates to 90°, the valve is fully open.
The handle butterfly valve has a simple structure and small volume. It can be seen in the water treatment, urban water supply and drainage, petroleum, chemical industry, and even the cooling water system of the thermal power station.

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

Tanghai Valve is committed to providing high-quality valve products and services to the society. The handle butterfly valve has always been our flagship product and one of the most satisfied products for customers. So in the highly competitive valve market, what are the advantages of the handle butterfly valve of Tanghai valve manufacturers?

1. Different handle design
The handle end of the handle butterfly valve adopts a humanized arc structure, which will not let the operator hurt his hand during operation, and it is more labor-saving to open and close.

2. Stainless steel handle bolts and disc pins
The bolts used on the handle and the pins on the butterfly plate are all made of stainless steel, and the corrosion resistance is more than 10 times that of ordinary products, making it safer to use.

3. Reinforcement at both ends of the butterfly plate
In order to prevent the instantaneous impact of the flowing medium to break the butterfly plate after the butterfly valve is installed, four reinforcing ribs are specially added at both ends of the butterfly plate.

4. Valve seat for vulcanization process
In order to ensure the sealing performance of the valve, the valve seat adopts the vulcanization process, which makes the valve seat and the valve body fit better, and the sealing surface is wider, which is more reliable than the sealing performance of ordinary butterfly valves.

5. Valve body painted with epoxy paint
If the butterfly valve is installed outdoors, the valve body is exposed, and it is easy to rust, which affects the service life of the valve. For this reason, Tanghai Valve specially sprays the valve body with epoxy resin paint, which makes the valve body of the butterfly valve more resistant to oxidation and can be safely installed outdoors.

6. Pressure test higher than the national standard
Each butterfly valve of Tanghai Valve must pass a pressure test higher than the national standard before leaving the factory.

7. Universal universal valve body
Tanghai Valve’s wafer butterfly valve adopts universal universal body, which can meet the national standard, German standard, American standard, Japanese standard, Korean standard, British standard and other standards at the same time, so as to meet the needs of different customers.

8. The natural rubber content of the valve seat exceeds 40%
The natural rubber content of the valve seat of the soft sealing butterfly valve is more than 40%, which has a longer service life than ordinary rubber.

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

Video of center-lined butterfly valve:

Structural characteristics and suitable medium of soft sealing gate valve

March 7, 2022

Structural characteristics of soft sealing gate valve:

Gate valves are mainly used in water-passing pipelines, but traditional gate valves may leak or corrode during use, which affects the performance of gate valves. As an upgraded product of traditional gate valves, the emergence of soft-sealed gate valves solves the problems of traditional gate valves that are easy to leak, easy to rust, and have poor elasticity. This article will give an introduction to the structural characteristics of soft sealing gate valves.

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

Soft sealing gate valve can be divided into dark rod soft sealing gate valve and rising rod soft sealing gate valve according to the structure. The working principle of the two structures is the same, the difference lies in the valve body structure, installation space, application range and so on. Details will be shared with you in future articles.

The structural characteristics of soft sealing gate valve are:
1. The valve body is made of ductile iron, which is lighter in weight and more conducive to installation and maintenance than traditional gate valves.
2. The valve body is coated with powder epoxy resin, which can play an anti-oxidation effect, prevent the valve body from being corroded, and is not easy to rust.
3. The traditional gate valve seat has grooves at the bottom. After the medium flows through, impurities in the medium such as stones, wood chips, iron chips and other debris will deposit and accumulate in the grooves at the bottom of the valve seat, which will cause the gate to fail to close completely over time. , causing leakage. The bottom of the valve seat of the soft-sealed gate valve is a flat-bottom design, and the medium containing impurities will not be precipitated and deposited when the valve body flows through, which ensures the sealing performance.
4. The gate of the soft-sealing gate valve is covered with high-quality rubber as a whole. The rubber and the gate are firmly attached, not easy to fall off, and have elastic memory, so that the gate and the valve seat can be tightly sealed to achieve good sealing performance. .

What medium is suitable for soft sealing butterfly valve:

In the introduction of the previous article, we learned that the sealing performance of the soft-sealed butterfly valve is superior, and it can achieve two-way sealing and zero leakage. The suitable media for soft seals are air, water, steam, various corrosive media, mud, oil, etc.
Butterfly valve can be divided into soft sealing butterfly valve and hard sealing butterfly valve according to the different sealing surface materials. The sealing surface refers to the valve seat of the butterfly valve. The sealing surface materials of the soft-seal butterfly valve we often see are EPDM, nitrile and PTFE. The three types of soft-sealed butterfly valves of different materials are also different in the applicable medium in the pipeline.

EPDM
Also called EPDM, codenamed EPDM. EPDM rubber is the most commonly used valve seat material for soft-seal butterfly valves, and it is also widely used. In the working environment of normal temperature and pressure, the use of EPDM valve seats has very good sealing performance. And EPDM rubber is resistant to ozone, aging, and has a long service life. The soft-sealed butterfly valve with EPDM as the valve seat material is suitable for fresh water, sewage, seawater and similar mud and other media containing impurities.

Nitrile
Nitrile-butadiene rubber, code-named NBR, has one of the biggest features of this material is its oil resistance is particularly good, in addition to a certain degree of wear resistance and heat resistance. The soft-sealed butterfly valve uses nitrile rubber as the sealing surface material, which can be used in oil pipelines and oily media. In addition, nitrile rubber is not suitable for medium such as fresh water, because it contains certain toxicity, which will cause harm to human health.

Teflon
PTFE is a fluoroplastic, code-named PTFE. The characteristics of PTFE are resistance to various acids and alkalis and various organic solvents; PTFE is used as the soft sealing partner of the valve seat material, which is mainly used in chemical industry, oil refining, chemical fiber, phosphate fertilizer, non-ferrous smelting, acid production, dyeing and other industries In the field, the applicable media are all corrosive strong acid and strong alkali media.
It can be seen from the above introduction that the soft sealing butterfly valve has a wide range of media and can be used in many fields. However, the soft sealing butterfly valve also has certain defects. Because of its own sealing material, it is not suitable for high temperature, high pressure and severe erosion conditions. In addition, in order to ensure the sealing performance of the soft-sealed butterfly valve, regular maintenance of its sealing surface should also be noted.

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

Video of resilient seated gate valve:

lug type dual plate check valve for marine industry-seawater

February 28, 2022

The dual plate check valve is divided into 3 types: Wafer type dual plate check valve, lug type dual plate check valve and double flanged dual plate check valve.

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

lug type dual plate check valve for marine industry-seawater (1)

lug 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 automatically closed under the action of the fluid pressure difference, its own gravity and other factors to prevent the fluid from flowing back.

lug type dual plate check valve for marine industry-seawater (2)

Model: H76X/H76H/H76W
Name: lug 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: lug double plate check valve (soft seal)
National Standard Number: H76X

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

Material of lug type dual plate check valve:

name	materials
Valve body	gray cast iron, ductile iron, carbon steel, stainless steel, aluminum bronze
Valve disc	ductile iron nickel-plated, stainless steel 201, stainless steel 304, stainless steel 316, aluminum bronze
Valve stem	WCB, 2Cr13, Stainless steel, Monel, duplex steel, steel alloy.
Valve seat	Rubber, stainless steel, steel alloy, Super Duplex Steel
Spring	60Si2Mn、3Cr13、17-7PH、INCONEL

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.

Features of lug dual plate Check Valve:

Simple structure and light weight, especially suitable for low-pressure large-diameter pipelines;
The paired clamp connection mode, the production process is simple, and the disassembly and assembly are convenient;
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.

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

Introduction and Description of Pneumatic Butterfly Valves

February 25, 2022

This article gives an introduction and description of the pneumatic butterfly valve. Pneumatic butterfly valve is a control terminal installed on industrial pipelines. Like electric butterfly valve, it belongs to automatic control valve. Pneumatic butterfly valves are now widely used in petroleum, chemical, electric power, metallurgy and other industries. They are usually used in pipelines in these industries and are not suitable for manual operation.

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

The working principle of pneumatic butterfly valve
The pneumatic butterfly valve absorbs dry and lubricated gases through positioners, solenoid valves or other equipment, controls them, and transmits these gases to the cylinder of the pneumatic actuator. This is the air source for the pneumatic actuator to work. When the cylinder is When the internal air source is introduced into the air chamber of the pneumatic actuator, the air pressure acts on the piston, and the generated thrust drives the output shaft to rotate, and at the same time drives the valve stem and the butterfly plate to rotate, thereby completing an opening and closing action of the butterfly valve. Adding a valve positioner to the pneumatic butterfly valve can also realize the precise opening adjustment of the butterfly valve. In addition, an intelligent positioner can also be used to connect with the field bus, so as to achieve the purpose of detecting the working state of the pneumatic butterfly valve and provide diagnosis.
Under the action of the pneumatic actuator, the pneumatic butterfly valve can open and close flexibly and quickly, which ensures the safety of the pipeline. It is a control valve that is used more in industrial pipelines. The parameters of the pneumatic butterfly valve can be divided into two parts, one is the basic parameters of the butterfly valve itself, and the other is the basic parameters of the pneumatic actuator.

Valve basic parameters

Valve Name	Pneumatic Butterfly Valve
Working medium	liquid, gas, oil, etc.
Working temperature	-29—400℃
Body Material	Cast Iron, Carbon Steel, Stainless Steel, Alloy Steel
Connection form	Flange, wafer, welding
Stroke	60°90°
Fault position	Fault on, fault off, hold position
Flow characteristics	Equal percentage (EQ-%)

Basic parameters of pneumatic device

Air source pressure	0.4-0.7mpa
Ambient temperature	-20-90℃
Location of accessories	Air filter pressure reducing valve, valve positioner, electric/pneumatic converter, solenoid valve, air control reversing valve, pneumatic amplifier, quick exhaust valve, manual operating mechanism, etc.

Installation and debugging of pneumatic butterfly valve
1. Before installing and using the pneumatic butterfly valve, thoroughly clean the valve body and pneumatic device of the butterfly valve.
2. Before installation, check whether the coating of the pneumatic butterfly valve is damaged. If any damage is found, please find a professional to repair it.
3. Like the electric butterfly valve, the installation area of the pneumatic butterfly valve is generally in a working condition with a certain risk factor. In this working condition, if the valve is to be moved, an accident may occur. At this time, the site must be covered with a suitable cover. Protect it.
4. The installation position of the solenoid valve should be as close as possible to the execution cylinder, and it must be as close as possible to the execution cylinder. The size of the air pipe is related to the air capacity. Before installing the pneumatic butterfly valve, the air intake hole and the solenoid valve must be kept clean. Cylinder actuators need to be lubricated.
5. The switch of the pneumatic butterfly valve must be too fast to avoid the pressure hitting the inside of the valve body and causing danger.
The above has made a simple price and description for the working principle, parameter information and installation and debugging of the pneumatic butterfly valve. If you have purchase requirements for the pneumatic butterfly valve, you are welcome to call the Tanghai Valve Hotline for consultation.

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

Video of center-lined butterfly valve:

Structural Characteristics and application of Centerline Butterfly Valves

February 23, 2022

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

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

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

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

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

Video of center-lined butterfly valve:

Introduction to the Characteristics and Uses of Centerline Wafer Butterfly Valves

February 21, 2022

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

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

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

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

Video of center-lined butterfly valve:

What is the reason for the poor sealing of the valve

February 17, 2022

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

marine valve seat

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

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

Video of center-lined butterfly valve:

Difference between forged valve and cast valve

Structure diagram of triple eccentric butterfly valve

How to install wafer butterfly valve and installation tips

Advantages of the handle butterfly valve of Tanghai valve manufacturer

Structural characteristics and suitable medium of soft sealing gate valve

lug type dual plate check valve for marine industry-seawater

Introduction and Description of Pneumatic Butterfly Valves

Structural Characteristics and application of Centerline Butterfly Valves

Introduction to the Characteristics and Uses of Centerline Wafer Butterfly Valves

What is the reason for the poor sealing of the valve

TH VALVE • PROFESSIONAL VALVE MANUFACTURER

GET IN TOUCH WITH US