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Common failures of butterfly valves and the characteristics of installation

July 17, 2020

Common errors of butterfly valves:
The rubber elastomer in the butterfly valve will tear, wear, aging, perforate or even fall off during continuous use. The traditional thermal vulcanization process is

Double flange butterfly valve (16)

difficult to meet the needs of on-site repair. Special equipment is used for repair, which consumes a lot of heat and electricity, which takes time and effort. Today, we use new method gradually of adopting polymer composite materials to replace traditional methods. The superior adhesion and excellent wear and tear resistance of its products ensure that the repair cycle reaches or even exceeds the life cycle of new parts, greatly reducing downtime.

Installation and maintenance of butterfly valves:
1. During installation, the valve disc should stop at the closed position.
2. The opening position should be determined according to the rotation angle of the butterfly valve disc.
3. Butterfly valves with bypass valves should be opened before opening.
4. The installation should be carried out according to the manufacturer’s installation instructions. The heavy butterfly valve should be installed with a solid foundation.

Construction and installation points
1. The installation position, height, and direction of entrance and exit must meet the design requirements, and the connection should be firm and tight. The handles of all kinds of manual valves installed on thermal insulation pipes must not be downward.
2. The valve must be visually inspected before installation, and the nameplate of the valve should comply with the customer’s national standards. For valves with a working pressure greater than 1.0 MPa and acting as a shut-off on the main pipe, strength and tightness performance tests should be carried out before installation, and qualified before use. During the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5min, and the valve housing and packing should be leak-free. During the tightness test, the test pressure is 1.1 times the nominal pressure; the test pressure lasts no less than 120 seconds during the test, and the valve flap sealing surface is qualified as no leakage.

Tianjin Tanghaidongyang valve Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves. Products range: 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…)

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

Applicable occasions of butterfly valve

July 14, 2020

Butterfly valves are suitable for flow regulation. Because the pressure loss of the butterfly valve in the pipeline is relatively large, the robustness of the butterfly plate to withstand the pressure of the pipeline medium when closing should also be considered. In addition, the working temperature limit of the elastic seat material

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

must be considered at high temperatures. The structure length and overall height of the butterfly valve are small, the opening and closing speed is fast, and it has good fluid control characteristics. The structure principle of the butterfly valve is most suitable for making large-diameter valves. When the butterfly valve is required for flow control, the most important thing is to correctly select the size and type of the butterfly valve so that it can work properly and effectively.

Generally, in throttling, adjustment control and mud medium, the structure length is required to be short, and the opening and closing speed is fast (1/4 turn). Low pressure cut-off (small differential pressure), butterfly valve is recommended.

Butterfly valve can be used when there are two-position adjustment, narrowing channel, low noise, cavitation and gasification, small leakage into the atmosphere, and abrasive media.

Throttle adjustment under special working conditions, or strict sealing requirements, or severe wear, low temperature (cryogenic) and other working conditions when using butterfly valves, need to use special design metal seal triple-eccentric or double eccentric Butterfly valve with adjustment device.

5 double-eccentric-butterfly-valve-2

The butterfly valve is suitable for requirements to achieve complete sealing, zero gas test leakage, high life requirements, and operating temperature between -10 degrees and 150 degrees. Applicable medium is fresh water, sewage, sea water, salt water, steam, natural gas, food, medicine, oil products And various acids and bases.

The soft seal eccentric butterfly valve is suitable for bidirectional opening and closing and adjustment of the ventilation and dust removal pipeline, and is widely used in gas pipelines and water channels in metallurgy, light industry, electric power, and petrochemical systems.

The metal-to-metal line sealed double eccentric butterfly valve is suitable for gas, oil, acid and alkali pipelines such as urban heating, gas supply, water supply, etc., as a regulating and throttling device.

In addition to being used as a large-scale pressure swing adsorption (PSA) gas separation device program control valve, the metal-to-metal face sealed triple-eccentric butterfly valve can also be widely used in the fields of petroleum, petrochemical, chemical, metallurgy, electric power, etc. as replacement product.

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

How to choose the right butterfly valve (2)

July 13, 2020

However, the following problems still exist during the use of this butterfly valve:
1. Due to the multi-layer soft and hard laminated seal ring fixed on the valve plate, when the valve plate is normally open, the medium forms a frontal flush on the sealing surface. The soft sealing tape in the metal sheet interlayer is directly affected by the flushing, which directly affects the sealing performance.

U-type flange butterfly valve, ductile iron, DI, center line,

2. Restricted by structural conditions, the structure is not suitable for valves with a diameter of DN200 or less, because the overall structure of the valve plate is too thick and the flow resistance is large.
3. Due to the principle of the three-eccentric structure, the sealing between the sealing surface of the valve plate and the valve seat is caused by the torque of the transmission device to press the valve plate against the valve seat. In the positive flow state, the higher the medium pressure, the tighter the seal extrusion. When the medium in the flow channel reverses flow, as the medium pressure increases, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, and the seal begins to leak.

The high-performance triple-eccentric bidirectional hard seal butterfly valve is characterized in that the valve seat sealing ring is composed of multiple layers of stainless steel sheets on both sides of a soft T-shaped sealing ring. The sealing surface of the valve plate and the valve seat is an oblique cone structure. The surface of the oblique cone of the valve plate is welded with a temperature-resistant and corrosion-resistant alloy material; the spring fixed between the pressure plate of the adjustment ring and the adjustment bolt of the pressure plate are assembled together.
This structure effectively compensates the tolerance zone between the shaft sleeve and the valve body and the elastic deformation of the valve stem under medium pressure, and solves the sealing problem of the valve in the process of bidirectional interchangeable medium transportation. The use of soft T-shaped multi-layer stainless steel sheets on both sides to form a sealing ring has the dual advantages of metal hard seal and soft seal. It has zero leakage sealing performance at low and high temperatures.
The test proves that when the pool is in the positive flow state (the medium flow direction is the same as the disc rotation direction), the pressure on the sealing surface is generated by the torque of the transmission device and the effect of the medium pressure on the valve plate. When the positive medium pressure increases, the tighter the surface of the valve plate oblique cone and the valve seat sealing surface are pressed, the better the sealing effect. In the reverse flow state, the seal between the valve plate and the valve seat is pressed against the valve seat by the torque of the driving device. As the pressure of the reverse medium increases, the unit positive pressure between the valve plate and the valve seat is less than the medium pressure, the deformation energy stored by the spring of the adjusting ring after being loaded compensates the tight pressure of the sealing surface of the valve plate and the valve seat Play the role of automatic compensation. Therefore, unlike the prior art, the utility model does not install soft and hard multi-layer sealing rings on the valve plate, but directly installs on the valve body. It is an ideal two-way hard sealing method to add an adjustment ring between the pressure plate and the valve seat. . It will replace gate valves, globe valves and ball valves.

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

How to choose the right butterfly valve (1)

July 13, 2020

When the butterfly valve is fully open to fully closed, it turns usually less than 90°. The butterfly valve and the butterfly stem itself have no self-locking capability. For the

U-type-flange-butterfly-valve-2

positioning of the butterfly plate, a worm gear reducer must be installed on the valve rod. The use of worm gear reducer can not only make the butterfly plate self-locking, stop the butterfly plate at any position, but also improve the valve performance. The characteristics of industrial special butterfly valve: can withstand high temperature, the applicable pressure range is also high, the nominal diameter of the valve is large, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of a rubber ring. Large high-temperature butterfly valves are manufactured by welding steel plates, and are mainly used for flue gas ducts and gas pipes of high-temperature media.

Selection:
The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. The butterfly valve is simple in structure, small in size and light in weight. It is composed of only a few parts, and can be quickly opened and closed only by rotating 90°. The operation is simple, and 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 resistance when the medium flows through the valve body. Therefore, the pressure drop generated by the valve is very small, so it has good flow control characteristics.

If the butterfly valve is required to be used as a flow control, the main thing is to choose the valve size and type correctly. The structural principle of the butterfly

wafer-type-butterfly-valve-with-handle-13

valve is especially suitable for making large-diameter valves. Commonly used butterfly valves are wafer-type butterfly valves and flanged butterfly valves. Wafer type butterfly valve is to use double-headed bolt to connect the valve between two pipeline flanges. Flange type butterfly valve is to use the process of connecting the flange of the valve to the pipeline flange with bolts.

The butterfly valve has been widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower, etc. as a component used to realize the on-off and flow control of the pipeline system. In the well-known butterfly valve technology, the sealing form mostly adopts a sealing structure, and the sealing material is rubber, polytetrafluoroethylene and the like. Due to the limitation of structural characteristics, it is not suitable for industries such as high temperature, high pressure, corrosion resistance and wear resistance.

An existing more advanced butterfly valve is a three-eccentric metal hard-sealed butterfly valve. The valve body and valve seat are connected components. The sealing surface layer of the valve seat is welded with temperature-resistant and corrosion-resistant alloy materials. The multi-layer soft stack type sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has high temperature resistance, is easy to operate, and has no friction when opening and closing. When closing, the torque is compensated with the increase of the torque of the transmission mechanism, which improves the butterfly valve. The sealing performance and the advantages of extended service life.

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

The main classification method of butterfly valve (2)

July 10, 2020

According to the connection method, the butterfly valve can be devided into four or five types:

1. Wafer type butterfly valve

Wafer type butterfly valve with worm gear

The butterfly plate of the wafer butterfly valve is installed in the diameter direction of the pipeline. The valve is fully open.
Wafer type butterfly valve has simple structure, small volume and light weight. There are two types of butterfly valve: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.

2. Lug butterfly valve

2 lug-type-butterfly-vlave-6

The butterfly plate of the lug butterfly valve is installed in the diameter direction of the pipeline. The butterfly plate rotates around the valve shaft, and the rotation angle is between 0°-90°. When it rotates to 90°, the valve is fully open.

3. Flanged butterfly valve

U-type flange butterfly valve, ductile iron, DI, center line,

Double flange butterfly valve (4)

The flanged butterfly valve has a vertical plate structure, and the valve stem is an integral type. Metal hard seal, valve sealing ring
It is a composite structure of flexible graphite plate and stainless steel plate, which is installed on the valve body, and the sealing surface of the butterfly plate is welded with stainless steel. The sealing ring of the soft seal valve is made of nitrile rubber, EPDM or VITON, and is installed on the butterfly plate. The sealing seat of the centerline sealed flange butterfly valve is directly fusion bonded on the valve body.
Flanged butterfly valves are divided into U-shaped butterfly valves and double-flanged butterfly valves according to the length of the structure. The U-type butterfly valve has a relatively short face to face structure, which reduces the weight of the valve body and saves space for use.

4. Welded butterfly valve
Welded butterfly valve is a non-hermetic butterfly valve, widely used in the construction materials, metallurgy, mining, electric power and other production processes, the medium temperature ≤300 ℃, the nominal pressure is 0.1Mpa pipeline, used to communicate, open or close or adjust the medium volume.

The electric regulating butterfly valve belongs to a variety of electric valves and electric regulating valves. The main connection methods are: flange type and wafer type, which are important execution units in the field of industrial automation control. Two major analysis points for the installation points of the electric adjustment butterfly valve: the installation position, height, and inlet and outlet directions must meet the design requirements. Note that the direction of the medium flow should be consistent with the direction of the arrow marked on the valve body, and the connection should be firm and tight. Before installing the electric butterfly valve, a visual inspection must be carried out. The nameplate of the valve should comply with the provisions of the current national standard “General Valve Mark” GB12220. For valves with a working pressure greater than 1.0 MPa and acting as a shut-off on the main pipe, a strength and tight performance test should be carried out before installation. Use only after passing the test. During the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5min, and the valve housing and packing should be leak-free. The electric adjustable butterfly valve can be divided into offset plate type, vertical plate type, inclined plate type and lever type according to the structural form; according to the sealing form, it can be divided into two types: soft seal type and hard seal type; soft seal type generally adopts rubber ring seal, hard seal type Usually a metal ring seal is used.

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

The main classification methods of butterfly valve (1)

July 10, 2020

There are several classification methods of butterfly valves.

According to the driving method
(1) Electric butterfly valve

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

(2) Pneumatic butterfly valve
(3) Hydraulic butterfly valve
(4) Manual butterfly valve
According to the structure:
(1) Center sealed butterfly valve
(2) Single eccentric sealed butterfly valve
(3) Double eccentric seal butterfly valve
(4) Triple eccentric seal butterfly valve

Sealing surface material:
(1) Soft seal butterfly valve.
1) The sealing pair is composed of non-metallic soft materials versus non-metallic soft materials.
2) The sealing pair is composed of metal hard material to non-metal soft material.
(2) Metal hard seal butterfly valve. The sealing pair is composed of metal hard material to metal hard material.
According to the sealing form:
(1) Forced sealing of butterfly valve.
1) Elastic sealing butterfly valve: The sealing specific pressure is caused by the valve plate squeezing the valve seat when the valve is closed, resulting in the elasticity of the valve seat or valve plate.
2) Impressed torque sealing butterfly valve: The sealing specific pressure is generated by the torque applied to the valve shaft.
(2) Pressure-filled sealing butterfly valve: The sealing specific pressure is generated by the pressure-filling of the elastic sealing element of the valve seat or valve plate.
(3) Automatic sealing butterfly valve: The sealing specific pressure is automatically generated by the medium pressure.

According to working pressure:
(1) Vacuum butterfly valve. Butterfly valve with working pressure lower than standard stack atmospheric pressure.
(2) Low-pressure butterfly valve. Butterfly valve with nominal pressure PN<1.6MPa.
(3) Medium pressure butterfly valve. Butterfly valve with a nominal pressure PN of 2.5-6.4 MPa.
(4) High-pressure butterfly valve. Butterfly valve with a nominal pressure PN of 10.0-80. 0MPa.
(5) Ultra-high pressure butterfly valve. Butterfly valve with nominal pressure PN>100MPa.

According to working temperature:
(1) High temperature. Butterfly valve with t>450 °C.
(2) Medium temperature butterfly valve. Butterfly valve with 120 C<t<450 ℃.
(3) Normal temperature butterfly valve. A butterfly valve at 40C<t<120 °C.
(4) Low temperature butterfly valve. A 100<t<- 40 °C butterfly valve.
(5) Ultra-low temperature butterfly valve. Butterfly valve with t<-100 °C.

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

The advantages and disadvantages of butterfly valves

July 10, 2020

Advantages of butterfly valve:

1. Convenient opening and closing, labor saving, low fluid resistance, and can be operated frequently.

wafer type butterfly valve, NBR seat (11)

2. The structure is simple, the external dimensions are small, the structural length is short, the volume is small, and the weight is light. It is suitable for valves with large diameter.

3. Mud can be transported, and the least liquid is accumulated in the pipe mouth.

4. Under low pressure, a good seal can be achieved.

5. Good adjustment performance.

6. When fully opened, the effective flow area of the valve seat channel is large, and the fluid resistance is small.

7. The opening and closing torque is small, because the butterfly plates on both sides of the rotating shaft are basically the same under the action of the medium, and the direction of generating torque is opposite, so the opening and closing are more labor-saving.

8. The sealing surface material is generally rubber, plastic, so the low-pressure sealing performance is good.

9. Easy installation.

10. Flexible and labor-saving operation, you can choose manual, electric, pneumatic, hydraulic mode.

Disadvantages of butterfly valve:

1. The operating pressure and operating temperature range are small.

2. Poor sealing.

Butterfly valves can be divided into offset plate type, vertical plate type, inclined plate type and lever type according to the structure.

According to the sealing form, it can be soft-sealed or hard-sealed. The soft seal type generally uses a rubber ring seal, and the hard seal type usually uses a metal ring seal.

According to the connection type, it can be divided into flange connection and wafer connection; 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 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

Structure and characteristics of butterfly valve

July 9, 2020

Butterfly valve is mainly composed of valve body, valve stem, butterfly plate and sealing ring. The valve body is cylindrical, with a short axial length and a built-in butterfly plate.

Double flange butterfly valve (16)

Features of butterfly valve:
1. The butterfly valve has the characteristics of simple structure, small size, light weight, low material consumption, small installation size, rapid switching, 90° reciprocating rotation, and small driving torque. It is used to cut off, connect, and adjust the medium in the pipeline. Has good fluid control characteristics and closed sealing performance.

2. The butterfly valve can transport mud and has the least liquid accumulation at the pipe mouth. At low pressure, a good sealing effect can be achieved. Good adjustment performance.

3. The streamlined design of the butterfly plate makes the fluid resistance loss small, which can be described as an energy-saving product.

4. The valve stem is a through-rod structure. After quenching and tempering, it has good comprehensive mechanical properties, corrosion resistance and scratch resistance. When the butterfly valve is opened and closed, the valve stem only rotates and does not move up and down. The filler of the valve stem is not easy to damage and the seal is reliable. It is fixed with the taper pin of the butterfly plate, and the outgoing end is designed to prevent the outgoing type, so as to prevent the valve rod from collapsing when the connection between the valve rod and the butterfly plate is accidentally broken.

5. Connection methods include flange connection, wafer connection, butt welding connection and lug wafer connection. The driving form includes manual, worm gear transmission, electric, pneumatic, hydraulic, electro-hydraulic linkage and other actuators, which can realize remote control and automatic operation.

You can check the types and structures of butterfly valve on this page: Butterfly 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

How does a butterfly valve work?

July 8, 2020

A butterfly valve is a valve that uses a disc-type opening and closing part to reciprocate around 90° to open, close, or regulate the flow of media. Butterfly valves are not only simple in structure, small in size, light in weight, low in material consumption, small in installation size, small in driving torque, easy in operation and fast, but also can have good flow adjustment function and close sealing characteristics at the same time. One of the fastest valve varieties. Butterfly valves are one of the fastest growing valve varieties in the past decade.

Butterfly valves are widely used. The variety and quantity of its use are still continuing to expand, and develop to high temperature, high pressure, large diameter,

Double flange butterfly valve (16)

high sealing, long life, excellent adjustment characteristics, and multi-function development of one valve. Its reliability and other performance indicators have reached a high level. With the application of chemically resistant synthetic rubber on butterfly valves, the performance of butterfly valves has been improved. Because synthetic rubber has the characteristics of corrosion resistance, erosion resistance, dimensional stability, good resilience, easy forming, and low cost, and can choose different performance synthetic rubber according to different use requirements to meet the working conditions of butterfly valves.

Polytetrafluoroethylene (PTFE) has strong corrosion resistance, stable performance, not easy to aging, low friction coefficient, easy to form, stable in size, and can be filled and added with appropriate materials to improve its comprehensive performance, resulting in better strength and friction coefficient The lower butterfly valve sealing material overcomes the limitations of synthetic rubber. Therefore, polymer polymeric materials represented by PTFE and its filling modified materials have been widely used in butterfly valves. Therefore, the performance of butterfly valves has been further improved, resulting in a wider temperature and pressure range and sealing performance, reliable and longer life butterfly valve.

butterfly valve working diagram-3D GIF animated presentation

In order to meet the requirements of industrial applications such as high and low temperature, strong erosion, and long life, metal seal butterfly valves have been greatly developed. With the application of high temperature resistance, low temperature resistance, strong corrosion resistance, strong erosion resistance, and high strength alloy materials in butterfly valves, metal sealed butterfly valves have been widely used in industrial fields such as high and low temperature, strong erosion, and long life. The emergence of butterfly valves with large diameter (9~750mm), high pressure (42.0MPa) and wide temperature range (-196~606℃) has brought the technology of butterfly valves to a whole new level.

When the butterfly valve is fully opened, it has a small flow resistance. When the opening is between about 15°~70°, the sensitive flow control can be performed, so the application of butterfly valves is very common in the field of large-diameter adjustment. Because the movement of the butterfly plate of the butterfly valve is wiping, most butterfly valves can be used for media with suspended solid particles. Depending on the strength of the seal, it can also be used in powder and granular media. Butterfly valves are suitable for flow regulation. Because the pressure loss of the butterfly valve in the pipe is relatively large, about three times that of the gate valve, when selecting the butterfly valve, the influence of the pressure loss of the pipeline system should be fully considered, and the strength of the butterfly plate to withstand the pressure of the pipeline medium when closing . In addition, the working temperature limit of the elastic seat material must be considered at high temperatures.

The structure length and overall height of the butterfly valve are small, the opening and closing speed is fast, and it has good fluid control characteristics. The structure principle of butterfly valve is most suitable for making large-diameter valve. When the butterfly valve is required for flow control, the most important thing is to correctly select the size and type of the butterfly valve so that it can work properly and effectively. Generally, in throttling, regulating control and mud medium, the structure length is short, the opening and closing speed is fast, and cut off at low pressure (small pressure difference). It is recommended to use a butterfly valve. Butterfly valves can be used when there are two-position adjustment, reduced diameter channels, low noise, cavitation and vaporization, a small amount of leakage into the atmosphere, and abrasive media.

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

How to achieve internal and external anti-corrosion of pneumatic valves

July 2, 2013

Pneumatic valve using pneumatic actuators, for which Air (or other gas) pressure is the source of power. Air pressure acts on the piston or bellows diaphragm, which produces a linear force on the valve stem. Pneumatic actuator is a kind of Power-operated actuators (using pneumatic, hydraulic or electric power), can remotely adjust valves, or quickly operate large valves.

In order to effectively guarantee the use efficiency of the pneumatic valve, and also to effectively extend the service life of the pneumatic valve, the internal and

Pneumatic actuator (2)

external corrosion protection of the pneumatic valve is a very important part of its use process, then we should pay attention to the main points for the internal and external corrosion protection of the pneumatic valve And what are the main items in the operation, we will give a brief introduction to you in the following article.

1. The inside of the valve body of the pneumatic valve and all parts of the valve plate require comprehensive corrosion protection. On the one hand, it will not rust in water, and there will be no electrochemical corrosion between the two metals; on the other hand, the smooth surface reduces the resistance to water.

2. Hygienic requirements of epoxy resin or paint for anti-corrosion of pneumatic valve body shall have a test report from corresponding authority. The chemical and physical properties should also meet the relevant requirements.

3. The inside and outside of the valve should first be shot blasted to remove sand and rust, and strive to

pneumatic valve structure

electrostatically spray powdered non-toxic epoxy resin with a thickness of more than 0.3mm. When it is difficult to electrostatically spray non-toxic epoxy resin for extra large valves, similar non-toxic epoxy paint should also be brushed and sprayed.

In addition, the pneumatic valve should also pay attention to the necessary maintenance during daily storage and transportation, including:

1. The pneumatic valve should be stored in a dry and ventilated room, and both ends of the passage must be blocked.
2. Valves stored for a long period of time should be checked regularly to remove dirt and apply anti-rust oil on the processed surface.
3. After the pneumatic valve is installed, regular inspections should be carried out. The inspection items are as

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

follows:
1) The wear of the sealing surface;
2) Trapezoidal thread wear of the stem and stem nut;
3) Whether the packing is out of date and invalid, and if damaged, it should be replaced in time.

TH Valve is one of the largest butterfly valve, check valve manufacturers in China. 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.

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

Common failures of butterfly valves and the characteristics of installation

Applicable occasions of butterfly valve

How to choose the right butterfly valve (2)

How to choose the right butterfly valve (1)

The main classification method of butterfly valve (2)

The main classification methods of butterfly valve (1)

The advantages and disadvantages of butterfly valves

Structure and characteristics of butterfly valve

How does a butterfly valve work?

How to achieve internal and external anti-corrosion of pneumatic valves

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