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Views: 34 Author: Site Editor Publish Time: 2024-10-28 Origin: Site
We have other type of butterfly valves: Lug type butterfly valve,U flange butterfly valve, double flange butterfly valve, fluorine lined PTFE butterfly valve,double eccentric butterfly valve and triple eccentric butterfly valves used in 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 butterfly valve was originally used where a tight closure was not absolutely necessary.However, over the years,these valves have been manufactured with fairly tight seals made of rubber or elastomeric materials that provide good shut off similar to other types of valves.Butterfly valves are used where space is limited. Unlike gate valves,butterfly valves can be used for throttling or regulating flow as well as in the full open and fully closed position.The pressure loss through a butterfly valve is small in comparison with the gate valve.The L/D ratio for this type of valve is approximately one-third of that of a gate valve.Butterfly valves are used in large and small sizes.Butterfly valves can be used as a control valve and also as a shut-off valve,against high pressure drops of regularly up to 415 barg.Depending upon the materials of construction and the seat design a butterfly control valve may have very limited shut-off pressure drops. Some 100 barg valves are only rated for 4 barg shut-off differential.A butterfly valve should have a range of possible shaft diameters for each nominal valve size in order to handle the variation in torque due to various operating pressure conditions and packing box friction. Shafts should not be made of material prone to creep, such as some austenitic stainless steels.In these situations a precipitation hardening stainless steel such as 17-4PH is preferred.The corrosion resistance of such materials, equivalent to AISI 304, must be borne in mind.
Generally, butterfly valves are used for the inlet control and bypass valves. They are inexpensive to manufacture,and their actuators are able to operate in accordance with the requisite response times. Butterfly valves do,however, have the disadvantage of a tightly curved characteristic.Additional non-linearities arise from the fact that valves of different nominal sizes are operated in sequence.An initial improvement in the control response was achieved in that the steady-state duty point characteristics for operation with and without the expander were stored in function generators in the controller.
A butterfly valve is a type of quarter-turn valve used to control the flow of fluid or gas through a pipeline. It operates by rotating a disc or vane inside the valve body, which is connected to a shaft.The disc can be turned parallel or perpendicular to the flow direction,allowing for precise control of the flow.
Here's how it functions:
1 Open Position:When the valve is fully open, the disc is rotated parallel to the direction of flow,allowing fluid or gas to pass through with minimal obstruction.This creates a clear passage for the medium to flow through the pipeline.
2 Closed Position:When the valve is fully closed,the disc is rotated perpendicular to the flow direction,blocking the passage completely.This prevents any fluid or gas from passing through the pipeline.
3 Intermediate Positions:The valve can also be adjusted to intermediate positions by partially rotating the disc.This allows for fine-tuning of the flow rate or for throttling the flow as needed.
4 Actuation:Butterfly valves can be actuated manually using a lever or gear mechanism,or they can be automated using pneumatic,hydraulic,or electric actuators.These actuators allow for remote operation and precise control of the valve position.
Overall,the simplicity of design and ease of operation make butterfly valves popular in various industries for applications where reliable flow control is essential.They are commonly used in water treatment plants,HVAC systems,chemical processing plants,and many other industrial applications.
The advantages of butterfly valves are the following:
1:Butterfly valves have low pressure drop, which benefits the pumping system of the pipeline.
2:Butterfly valves are quick-acting and have a simple operating mechanism. There are various types of automatic actuation systems that can be utilized in operating butterfly valves.
3:Butterfly valves are more compact and have a simpler construction and lighter weight than other valve types. Hence,they generally consume less space and material.This is because they are designed to fit between two pipe flanges.They are cheaper alternatives to globe valves and gate valves.They also require less maintenance.
4:Butterfly valves can operate at a wider range of temperatures and pressures than ball valves.Soft seats can be backed with metal seats to increase their temperature and flame resistance for fire prevention applications.
5:Butterfly valves can handle large fluid flows at relatively low pressures as well as liquids containing suspended solids.
The limitations of butterfly valves are the following:
1:Throttling in butterfly valves is limited to low pressure differentials.
2:Butterfly valves have a poor sealing function. Effective sealing is achieved at low pressures.
3:Butterfly valves require high torque during operation.
4:Cavitation and choking are potential concerns in butterfly valves.
A butterfly valve is a quarter-turn valve that controls the flow of fluid through a pipe by rotating a disc-shaped component in the valve body.The disc is attached to a stem that passes through the center of the disc and is connected to an actuator,which can be manually operated or automated. When the valve is fully open,the disc is perpendicular to the flow of fluid,allowing for maximum flow.When the valve is fully closed,the disc is parallel to the flow of fluid,blocking the flow completely.
A butterfly valve typically consists of the following components:
Body:The main housing of the valve contains the disc, stem, and actuator.
Disc:The disc is the component that rotates within the valve body to control the flow of fluid.
Stem:The stem connects the disc to the actuator and passes through the center of the disc.
Actuator:The actuator is the component that opens and closes the valve. It can be manually operated or automated, depending on the application.
Seat:The seat is the component that provides a tight seal around the disc when the valve is closed.
Bolts:The bolts hold the valve components together and secure the valve to the piping system.
There are three main types of butterfly valves:
Wafer Butterfly Valves:Wafer butterfly valves are designed to fit between two flanges and are held in place by bolts that pass through the valve body and the flanges.They are the most common type of butterfly valve and are suitable for various applications, such as HVAC systems,pharmaceutical processing, food processing,water treatment plants, or chemical processing.
Lug Butterfly Valves:Lug butterfly valves have threaded inserts on either side of the valve body that allow them to be bolted to the pipe.They are often used in applications where the valve needs to be easily removed from the piping system for maintenance or replacement.
Flanged Butterfly Valves:Flanged butterfly valves have flanges on either side of the valve body that allow them to be bolted directly to the pipe.They are suitable for applications where high-pressure or high-temperature fluids are being transported.
When choosing a butterfly valve for your application,it is important to consider several factors to ensure optimal performance,efficiency,and safety.The following are some of the key factors to consider:
Fluid Characteristics: The fluid transported through the valve will have a significant impact on the type of butterfly valve that is suitable for the application. Factors to consider include:
Temperature: The fluid’s temperature can affect the construction material, as some materials may not be suitable for high-temperature applications.
Pressure: The pressure of the fluid can impact the design of the valve, as higher pressure applications may require a stronger valve construction.
Viscosity: The fluid’s viscosity can affect the flow rate and the valve size required.
Corrosiveness: If the fluid is corrosive, the valve material must resist corrosion.
Application:The specific application will also influence the type of butterfly valve required. Factors to consider include:
Industry: Different industries have different requirements for butterfly valves. For example, food processing applications may require valves that are easy to clean and have sanitary designs.
Function: The function of the valve (e.g., shut off, throttling) will determine the type of valve required.
Location: The valve’s location (e.g., above or below ground) will impact the design and construction.
Size of the Valve:The required valve size will depend on the flow rate and pressure of the transported fluid.Therefore,choosing the right valve size is important to ensure optimal performance and prevent issues such as flow restriction or leakage.
Material of Construction:The material of construction impacts one’s choice in that different materials are better suited for different fluid characteristics and applications.Common materials for butterfly valves include stainless steel, PVC, and cast iron.
Stainless Steel: Stainless steel is highly durable and corrosion-resistant,making it ideal for use in applications with harsh chemicals,high temperatures,and corrosive environments,such as in the chemical processing,food and beverage,and pharmaceutical industries.Stainless steel also has a smooth surface finish,making it easy to clean and maintain,which is important in industries where cleanliness and hygiene are critical.
PVC:PVC (polyvinyl chloride) is a lightweight and cost-effective material commonly used in applications with low-pressure and low-temperature requirements,such as in water treatment plants and swimming pool systems.PVC is resistant to chemical corrosion and easy to install and maintain.
Cast Iron: Cast iron is a durable and long-lasting material commonly used in applications with high pressures and temperatures,such as in the oil and gas industry.Cast iron is also relatively inexpensive compared to other materials,making it a cost-effective choice for applications where cost is a significant factor.
Cost and Budget Considerations:The cost of the valve will depend on the type of valve required,the construction material, and the valve’s size.Therefore,balancing cost considerations with the required performance and safety features is important.
Environmental and Safety Requirements:Environmental and safety regulations may dictate the type of valve required. For example,valves used in the food industry may need to meet FDA and USDA requirements for food safety.In contrast, valves used in high-pressure applications may need to comply with specific safety standards.
Butterfly valves are commonly used in various industries due to their versatility and efficiency.They come in different types such as flanged butterfly valve, lever butterfly valve, lug butterfly valve, wafer butterfly valve, and worm gear butterfly valve.Each type serves specific purposes and offers unique features to meet different requirements.Flanged butterfly valves are ideal for applications requiring easy installation and maintenance, while lever butterfly valves are known for their simple operation.Lug butterfly valves provide a secure seal and are suitable for high-pressure systems.Wafer butterfly valves are compact and lightweight,making them ideal for tight spaces.Worm gear butterfly valves offer precise control and are often used in industrial processes.
