Performance Characteristics
Flow Control
The lug type manual butterfly valve provides excellent flow control capabilities. The linear relationship between the disc's angle of rotation and the flow rate allows for accurate modulation of fluid flow. This makes it suitable for applications where maintaining a specific flow rate is essential, such as in chemical processing plants and water treatment facilities.
Sealing Performance
Typically, these valves are equipped with elastomeric seats, such as EPDM (Ethylene - Propylene - Diene Monomer), NBR (Nitrile - Butadiene Rubber), or PTFE (Polytetrafluoroethylene). The seat material forms a tight seal against the disc when the valve is closed. A well - designed seat can effectively prevent leakage, even under high - pressure differentials. Many lug type manual butterfly valves are engineered to offer bi - directional sealing, ensuring reliable performance regardless of the flow direction.
Pressure and Temperature Resistance
The valve's body is commonly made of materials like cast iron or stainless steel, which endow it with the ability to withstand moderate to high pressures. Pressure ratings often include PN10, PN16 for European standards, and ANSI Class 150 in the American system. The temperature resistance of the valve is determined by the seat material. For example, EPDM seats are suitable for temperatures ranging from approximately - 20°C to 80°C, while PTFE seats can handle temperatures up to 200°C.
Advantages
Installation Stability
The lug design significantly improves installation stability. The through - bolts that pass through the lugs and pipeline flanges hold the valve firmly in place, reducing the risk of misalignment or leakage due to vibrations or movement in the pipeline. This makes it an ideal choice for applications where the pipeline system is subject to mechanical stress.
Cost - effectiveness
Compared to some more complex valve types, the lug type manual butterfly valve is relatively cost - effective. Its simple design with fewer parts results in lower manufacturing costs, which are ultimately passed on to the end - user. Additionally, the use of common materials like cast iron or stainless steel for the body further contributes to its affordability.
Compact Design
Despite the presence of lugs, the valve maintains a relatively compact size. This is beneficial for installations where space is limited, such as in industrial plants with crowded piping systems or in buildings where mechanical room space is restricted. The compact design also allows for easier integration into existing pipeline networks.
Easy Operation
The manual operation of the valve via a handwheel or lever makes it accessible to operators without the need for complex control systems. The 90 - degree rotation of the disc enables quick opening and closing, which is useful in applications where rapid response times are required, such as in emergency shut - off situations.
Application Scenarios
Water and Wastewater Systems
In water treatment plants, lug type manual butterfly valves are used to control the flow of raw water, treated water, and chemicals. In wastewater treatment facilities, they regulate the flow of sewage, sludge, and effluent. Their ability to handle large volumes of fluid and resist corrosion from water - based substances makes them highly suitable for these applications.
HVAC Systems
In heating, ventilation, and air - conditioning (HVAC) systems, these valves are used to control the flow of water or refrigerant. They help maintain the desired temperature and pressure within the system, ensuring efficient operation. The ease of manual operation allows for on - site adjustments as needed.
Industrial Processes
In various industrial sectors, such as food and beverage production, chemical manufacturing, and oil and gas processing, lug type manual butterfly valves are used to control the flow of different fluids. In food and beverage production, they can regulate the flow of ingredients like water, milk, or syrups. In chemical manufacturing, with the appropriate seat material, they can handle corrosive chemicals.
Power Generation
In power plants, these valves are utilized in cooling water systems, steam lines, and other fluid - handling applications. They play a vital role in regulating the flow of water for cooling turbines, controlling steam supply, and managing the flow of various chemicals used in the power generation process.
Technical Parameters
Size
The size of lug type manual butterfly valves is typically specified in nominal diameters (DN) or inches. Common sizes range from DN50 (2 inches) to DN1000 (40 inches), although custom sizes may also be available to meet specific application requirements.
Pressure Rating
Common pressure ratings include PN10 (10 bar), PN16 (16 bar) according to European standards, and ANSI Class 150 (approx. 2070 kPa) in the American system. The pressure rating indicates the maximum pressure the valve can safely handle during normal operation.
Temperature Range
The temperature range depends on the seat material. For EPDM seats, it is generally - 20°C to 80°C, for NBR seats - 20°C to 100°C, and for PTFE seats - 100°C to 200°C.
Material
Disc: Can be made of materials such as cast iron, ductile iron, or stainless steel, depending on the application's requirements.
Seat: Elastomeric materials like EPDM, NBR, PTFE, or FKM (Fluorocarbon Rubber) are used. Each material has its own unique properties in terms of chemical resistance, temperature resistance, and sealing performance.
Maintenance
Regular Inspection
Regularly inspect the valve for any signs of leakage, damage to the body or disc, and proper operation of the handwheel or lever. Check the condition of the seat for wear or cracks. Visual inspections can be carried out during routine maintenance shutdowns.
Cleaning
Periodically clean the valve to remove any dirt, debris, or deposits that may accumulate on the valve body, disc, and seat. A suitable cleaning agent and a soft brush can be used. In applications where the fluid contains solids or contaminants, more frequent cleaning may be necessary.
Lubrication
Lubricate the moving parts of the valve, such as the shaft and the connection between the handwheel/lever and the shaft, to ensure smooth operation. Use a lubricant that is compatible with the materials of the valve and the fluid being handled. The lubrication intervals should be based on the manufacturer's recommendations and the operating conditions of the valve.
Seat Replacement
If the seat shows signs of excessive wear or damage, it should be replaced. The replacement process typically involves removing the old seat, cleaning the seat - mounting area, and installing the new seat. Ensure that the new seat is compatible with the valve model and the application requirements.
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