Electric Butterfly Valve-FAQ

The electric butterfly valve is one of the electric valves and electric regulating valves, which can be divided into manual, gear-driven, pneumatic, hydraulic, and electric according to the transmission mode, and is a vital execution unit in the field of industrial automation control.

The electric butterfly valve controls the opening and closing of the butterfly valve by means of a power signal. Thus, the product can be used as a cut-off valve, control valve, and check valve of the pipeline system. In addition, with a manual control device, once the power supply fails, it can be operated temporarily by hand without affecting the use.

Electric butterfly valves are widely used in textile, power station, petrochemical, heating and cooling, pharmaceutical, shipbuilding, metallurgy, light industry, environmental protection, and other fields. The products can be used as cut-off valves, control valves, and check valves for pipeline systems. A complete range of manual control devices, electric or pneumatic drives are available to meet the specific conditions of different working conditions. They meet the most stringent quality requirements and can be used for very long-lasting applications. Mainly well known in the metallurgical, steel, and marine industries.

 

What’s an electric butterfly valve？ 

An electric butterfly valve is called by the combination of an electric actuator and butterfly valve, the same need for torque configuration to meet the international common ISO5211 connection standard platform and mutual ± 5 ° fine-tuning, and to achieve precision concordance.

Actuator, electric actuator 90 ° 120 ° 180 ° 270 ° rotation angle stroke torque control is divided into switch passive contact feedback type / intelligent adjustment type, unique environment explosion-proof, explosion-proof type. Rugged aluminum alloy shell Execution power supply DC24v, AC220v, AC380v, etc. Built-in overheating protection, the central control feedback signal, see-through indicator window, power failure emergency manual device Protection class IP67 Bottom mounting dimensions following ISO5211/DIN3337 international standards Adaptation to ambient temperature 80°C, epoxy resin coating Detailed data to be provided separately by the supplier.

What’s the working principle of the electric butterfly valve？

 

The working power supply is usually: AC220V, AC380V, etc. Input signal: 4~20mA 0~10v and other weak electrical signals. After the electric adjustment actuator and valve stem are connected and debugged, the electric energy is used as the driving force to drive the hard seal butterfly valve plate for 0~90° partial rotary movement. Receive 4~20mA signal from the industrial automation control system to precisely control the valve opening degree to achieve the regulation and control of different process parameters such as flow, temperature, and pressure.

What types of butterfly valves can be divided into？

1. By structure type：

1)Center-sealed electric butterfly valve

2)Single eccentric sealed electric butterfly valve

3)Double eccentric sealed electric butterfly valve

4)Three eccentric seal electric butterfly valve

2. By sealing surface material：

1) Soft seal electric butterfly valve

Its sealing vice by a non-metallic soft material to non-metallic soft material composition and hard metal material to non-metallic soft material composition two.

2) Metal hard seal electric butterfly valve

The sealing side of which is composed of hard metal material to metal hard material.

3. By sealing form:

1)Forced sealing electric butterfly valve

Also known as resilient seal electric butterfly valve sealing ratio pressure by the valve plate squeeze valve seat when the valve is closed, the seat or plate elasticity generated; external torque seal electric butterfly valve, sealing ratio pressure by the torque applied to the valve shaft developed.

2) Pressure filled seal electric butterfly valve

Sealing pressure is generated by the resilient sealing element on the valve seat or plate.

3)Automatic sealing electric butterfly valve

The sealing pressure is generated by the medium pressure automatically.

4. By working pressure:

1)Vacuum electric butterfly valve

The working pressure is lower than the standard atmospheric pressure electric butterfly valve.

2) low-pressure electric butterfly valve

The nominal pressure ≤ PN16

3) Medium pressure electric butterfly valve

The nominal pressure of PN25 ~ PN63 electric butterfly valve.

4) High-pressure electric butterfly valve.

The nominal pressure is PN100 ~ ~ PN800 electric butterfly valve.

5. By working temperature:

1) High-temperature electric butterfly valve. The t>450℃ electric butterfly valve.

2)Medium temperature electric butterfly valve.120℃ <t≤450℃ electric butterfly valve.

3) Normal temperature electric butterfly valve.-29℃ ≤t≤120℃ electric butterfly valve.

4) Low-temperature electric butterfly valve.-100℃ <t<-29℃ electric butterfly valve.

5)Ultra-low temperature electric butterfly valve.The electric butterfly valve for t≤-100℃.

6. By connection method:

1)Wafer type electric butterfly valve

2)Flange type electric butterfly valve

3)Trunnion type electric butterfly valve

4)Welded type electric butterfly valve

What are the components of an electric butterfly valve?

 

Parts and Materials
NO.	Parts Name	Material
1	Bonnet bush	Copper base alloy
2	Disc	Stainless steel or Ductile iron
3	Seat seal ring	PTFE/NBR/EPDM
4	Valve Body	Stainless steel, Cast iron, Carbon steel
5	Bolt	35 Steel, Carbon steel, Stainless steel
6	Valve stem	45 Steel, Stainless steel
7	Key	45 Steel, Stainless steel
8	Bonnet bush	Copper base alloy
9	O Seal ring	PETE, EPDM
10	Electric actuator	RTK series

 

The electric butterfly valve is mainly composed of the valve body, valve seat, gate, and stem. The direction of movement of the gate is perpendicular to the direction of the fluid. The electric butterfly valve is sealed in both directions by the valve seat and the gate. Usually, the sealing surface is welded with metal materials to improve wear resistance, such as 1Cr13, STL6, stainless steel, etc. The entrance has a rigid gate and a flexible gate. Depending on the gate, electric butterfly valves are divided into severe electric butterfly valves and resilient electric butterfly valves.

The gate of a wedge-type electric butterfly valve can be made as a single unit called a rigid gate; it can also be made with a gate that can be slightly deformed to improve its manufacturability and compensate for deviations in the angle of the sealing surface during machining. Thus, the gate is known as a resilient gate. Electric butterfly valves generally use forced sealing, i.e., they rely on external forces to push the gate against the seat to ensure the sealing performance of the sealing surface.

The gate of an electric butterfly valve moves linearly with the stem, known as a lifting lever electric butterfly valve, also known as a rising lever electric butterfly valve. Typically, a trapezoidal thread on the rising stem passes through a nut at the top of the valve and a guide slot in the valve body. As a result, its movement becomes linear, i.e., the operating torque becomes the working thrust. In some electric butterfly valves, the stem nut is mounted on the gate and the rotation of the handwheel drives the rotation of the stem to lift the gate. This type of valve is called a stem electric butterfly valve or a concealed stem electric butterfly valve.

What are the structural characteristics of electric butterfly valves?

1. It has stable sealing performance under high temperature and pressure conditions. Its unique sealing system ensures high sealing performance in all temperature ranges from ultra-low to ultra-high.
2. The triple eccentric sealed system and the optimized design allow the valve to be opened with very little resistance. The sealing surface of the butterfly plate is a conical shape that is raised upwards so that the points on the circumference of the butterfly plate can be separated from the sealing ring at the same time when the valve is opened. The closing process of the valve is accomplished by the elastic pressure of the sealing ring.
3. There is no interlocking between the butterfly plate and the sealing ring.
4. Temperature fluctuations do not influence the valve’s sealing performance.
5. The stem bore is sealed with a graphite pressed seal. In summary, to ensure zero leakage, metal seal plus before, during, and after the fire are zero leakage, so is the essence of fire safety type.

 

What are the features of an electric butterfly valve?

1. Adopt a double eccentric structure to tighten the seal the more it is closed; the sealing performance is reliable.
2. The sealing sub-materials are paired with stainless steel and nitrile oil resistant rubber, with long service life.
3. The rubber seal ring can be placed both on the valve body and on the butterfly plate, which can be used for different characteristics of the medium for customers to select.
4. The butterfly plate adopts a high-strength frame structure, sizeable over-flow area, and low flow resistance.
5. The whole baking paint can effectively prevent rust and corrosion and can be used in different media as long as the sealing seat sealing material is changed.

6. The valve has a bi-directional sealing function, and the installation is not controlled by the flow direction of the medium of the space location. Therefore, it can be mounted in any orientation.

7. With small volume, lightweight, reliable performance, simple supporting, large circulation capacity, especially suitable for the medium is more clean liquid and gas.

What are the advantages and disadvantages of an electric butterfly valve？

Advantages：

1. An electric butterfly valve is convenient to open and close quickly, saves effort, has small fluid resistance, can be operated frequently.
2. The electric butterfly valve has a simple structure, small volume, and is lightweight.
3. The electric butterfly valve can transport slurry and accumulate the least liquid at the mouth of the pipeline.
4. The electric butterfly valve provides a good seal at low pressure.
5. The electric butterfly valve has good adjustment performance.

Disadvantages：

1. A small range
2. The sealing is poor.

What are the primary uses of electric butterfly valves？

Electric butterfly valves are used to control pipeline flow, pressure, and temperature in various industrial automation products. For example, electric power, metallurgy, petrochemical, environmental protection, energy management, fire-fighting systems, etc.

Electric clamp butterfly valve, suitable for temperature ≤ 80 ~ 120 ℃, such as food, chemical, petroleum, electric power, light textile, paper, and other water supply and drainage, the gas pipeline for regulating the flow and intercepting the role of media.

For the Electric soft seal butterfly valve, not only the valve seat can be lined, but the butterfly plate can also be lined so that it cannot pollute the media. This advantage is the standard ball valve can not reach moldability.

Electric hard seal butterfly valve, using hard overlay alloy or stainless steel, making the sealing surface high strength, good hardness, wear resistance, can be continuously opened and closed more than 60,000 times without damage.

Electric flange butterfly valve, because the three-dimensional eccentric principle designs this product butterfly valve, so that the space movement trajectory of the sealing surface is idealized, no friction and interference between the sealing surface, coupled with the proper choice of sealing materials, so that the sealing, corrosion resistance, high-temperature resistance and wear resistance of the butterfly valve are reliably guaranteed.

Electric regulating butterfly valve, electric controlling butterfly valve with 220VAC power supply as the power, accept 0~10mA or 4~20mA standard signal, drive the valve opening degree and this operation signal corresponding to the purpose of regulating medium pressure, flow, temperature, simple structure, easy operation. The valve plate is an elliptical slant off the system; leakage is small. Suitable for large diameter, significant flow occasions. Because of the self-cleaning effect, it is especially ideal for regulating ventilation systems and media containing suspended particles.

Electric rubber-lined butterfly valve, suitable for use in freshwater, seawater, salts, weak alkalis, weak acids, natural gas, air, steam, oil, food, and other media.

Electric ventilation butterfly valve, electric ventilation butterfly valve using the same material as the valve body processed into the seal, its applicable temperature with the valve body selection material, nominal pressure ≤ 0.6MP work, generally relevant to industrial, metallurgical, environmental protection, and other pipelines for ventilation to regulate the flow of media.

The main features of the electric expansion butterfly valve are as follows: novel design, reasonable, unique structure, lightweight, convenient operation, rapid opening and closing; expansion butterfly valve can be used for regulating and intercepting the flow, compensating for the thermal expansion and contraction function arising from the temperature difference of the pipeline, but also for the installation and replacement, maintenance of the valve to provide convenience. Moreover, the sealing part can be adjusted and replaced, the sealing performance is reliable, etc.

How to select an electric butterfly valve?

Suppose you need a powerful electric butterfly valve that is easy to store, reliable, and suitable for dense, granular, and fibrous media. In that case, the electric middle line butterfly valve is a good choice. It is ideal for a wide range of media and applications.

Suppose you are looking for a new design with high corrosion resistance and use it in drinking water systems, drainage, and wastewater systems. In that case, the electric butterfly valve is the right choice. It is manufactured using superior technology, has a beautiful structure, is made of wear-resistant and long-lasting material, and has good chemical resistance, which users widely appreciate.

If you need a butterfly valve that avoids internal contamination and offers high performance, the electric sanitary butterfly valve is the one for you.  It has the ease of installation and durability of a butterfly valve. What is more,  its unique design prevents various media from accumulating on the surface, ensuring maximum hygiene and no contamination, so it can meet your hygiene requirements and giving you a higher quality return.

How to use electric butterfly valves?

 The butterfly valve’s butterfly plate is mounted in the direction of the pipe diameter. In the butterfly valve body’s cylindrical passage, the butterfly plate in the shape of a disc rotates around its axis with a rotation angle between 0° and 90°. When it pivots to 90°, the valve is in a fully open state.

The butterfly valve has a simple structure, is small, lightweight, and only consists of a few pieces. It can be opened and closed quickly and easily by rotating it by 90°, and the valve has good fluid control characteristics. When the butterfly valve is in the completely open position, the butterfly plate thickness is the pressure resistance of the medium that flows through the valve body. Therefore the voltage drop through the valve is minimal, so it provides good flow control features. Butterfly valves have two types of sealing, such as resilient sealing and metal sealing. For valves with resilient seals, the seal can be embedded in the valve body or affixed to the perimeter of the butterfly plate.

With metallic seals, the valves typically have a significantly longer life than those with elastic seals, but it isn’t easy to achieve a complete seal. Furthermore, metal seals can be adapted to higher working temperatures, whereas the disadvantage of resilient seals is limited by temperature. If a butterfly valve is needed as flow control, the key is to choose the correct size and the right type of valve. The structural principle of the butterfly valve is particularly suitable for the production of large diameter valves. Butterfly valves are widely used in the oil, gas, chemical, and water treatment industries in general and in the water cooling systems of coal-fired power stations. There are two types of butterfly valves in everyday use: the butt-clamp butterfly valve and the flange butterfly valve. The clamping type butterfly valve is connected between two pipeline flanges with double-headed bolts, and the flanged butterfly valve is with flanges on the valve. And the flanges at each end of the valve are bolted to the pipe flange.

What are the application areas of electric butterfly valves？

 

Electric butterfly valves are widely used in automatic control systems for industrial processes in food, environmental protection, light industry, petroleum, chemical, water treatment, municipal engineering, paper making, electric power, water treatment, and other industries.

The electric butterfly valve is suitable for the HVAC and refrigeration industry and can also be used in industrial, general service, and water treatment.

The electric butterfly valve is suitable for occasions where flow regulation is required. As the pressure loss of the butterfly valve in the pipeline is relatively significant, about three times that of the gate valve, therefore, when selecting a butterfly valve, full consideration should be given to the influence of the pipeline system by the pressure loss and the sturdiness of the butterfly plate to withstand the pressure of the pipeline medium when it is closed should also be considered. In addition, consideration must also be given to the working temperature limits to which the resilient valve seat material is subjected at high temperatures. With its small structural length and overall height, fast opening and closing speed, and good fluid control characteristics, the butterfly valve construction principle is best suited to the production of large diameter valves. Therefore, when butterfly valves are required for flow control use, the most important thing is to select the correct size and type of butterfly valve to work appropriately and effectively.

Electric butterfly valves are usually applied for flow throttling, adjusting control, and slurry medium, requiring temporary structure length and fast opening and closing speed (1/4 turn).

Low-pressure shut-off (slight differential pressure), the butterfly valve is recommended.

In double-position regulation, indented ground channel, low noise, cavitation and cavitation phenomenon, a small amount of leakage to the atmosphere, with abrasive media, butterfly valves can be selected.

The use of butterfly valves under particular circumstances, such as flow throttling and regulation, strict tight sealing requirements, extreme wear, and tear, or low temperature (deep freeze) conditions, requires the use of specially designed metal sealed triple or double eccentric butterfly valves with regulating devices.

 

What are the common faults of electric butterfly valves, and how to eliminate them?

Common faults and elimination methods of an electric butterfly valve

1. Electric butterfly valve installation before the road to confirm product performance and media flow arrow is consistent with the movement of the working conditions. The valve cavity inserted clean, not allowed in the seal ring and butterfly plate with impurities foreign matter, not cleaned before never allowed to close the butterfly plate, so as not to damage the seal ring.
2. Electric butterfly valve installation supporting flange is recommended to use the special flange of disc valve, namely HGJ54-91 socket welding steel flange.
3. The electric butterfly valve installed in the pipeline is the best position for vertical installation but can not be installed upside down.
4. The electric butterfly valve needs to regulate the flow in use and has a pneumatic actuator for control.
5. In about two months, the manual butterfly valve, which is opened and closed more times, open the worm gearbox cover and check whether the grease is standard, it should keep the right amount of oil.
6. Check the requirements of each coupling part pressed tightly, that is, to ensure the sealing of the packing, but also to ensure that the valve stem rotation is flexible.
7. Metal seal electric butterfly valve is not suitable for installation at the end of the pipeline, such as must be installed at the end of the pipeline, it is necessary to take equipped with export flange, to prevent the seal ring pressure accumulation, over the position.
8. The valve stem is installed and used in response to regular inspection of the valve’s use effect, and faults are found and eliminated in time.

Electric butterfly valve sealing surface leakage troubleshooting

1. Butterfly plate, sealing surface entrapped with debris
2. Butterfly plate, sealing surface closing position incorrect fit
3. Uneven force on the flange bolts of the export side configuration

Electric butterfly valve two end face leakage troubleshooting

1. Both sides sealing gasket failure
2. Uneven tightening force of pipe flange or not pressed
3. Seal ring upper and lower sealing gasket failure

How to install electric butterfly valves？

 

1. Installation position, height, import, and export direction must meet the design requirements. Pay attention to the direction of media flow should be consistent with the direction of the arrow marked on the valve body. The connection should be solid and tight.
2. The valve must be checked for visual appearance before assembly, and the valve’s nameplate is required to be by the existing standard “General Valve Marking” GB 12220.
3. For working pressure greater than 1.0 MPa and in the main pipe to play a cut-off role in the valve, the strength and tightness of the performance test should be carried out before installation, after passing before use.
4. Strength test, test pressure for the nominal pressure of 1.5 times the duration of not less than 5min, the valve shell, packing should be no leakage for qualified.
5. For tightness tests, the test pressure must be 1.1 times the nominal pressure; the test time also needs to match the GB 50243.

What to pay attention to in the maintenance process of the electric butterfly valve?

 

For the installation of electric butterfly valves, pay attention to safety issues.

To let the butterfly valve after installation smoothly through the commissioning and trial, to ensure that the workplace is safe, try to prevent the butterfly valve in the temperature difference between the environment to use the butterfly valve. The environment with huge temperature difference will make the butterfly valve’s tightness present a problem and cannot reach the reasonable operating condition.

At the same time, the sealing of the butterfly valve is best accomplished under low air pressure, so we have to regulate the air pressure in the workplace.

In addition, when installing the butterfly valve, the control element should be in a closed position to prevent safety problems after the line is connected. Finally, when protecting the electric butterfly valve, you should try to keep the whole equipment in a ventilated environment to prevent excessive grease stains from blocking the butterfly valve’s piping, which will significantly affect the role and function of the entire kit.

In addition, to make the operation of the butterfly valve more stable, it should be fixed on top of the stable equipment. The installation and protection of butterfly valves are subject to many rules and operating specifications so that professionals can be trained in the techniques and then specialized in handling and operating them.