Detailed Analysis of Butterfly Valve Structures Comparison of Wafer Type, Flanged Type, and Lug Type
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Butterfly valves, as a common type of valve used in fluid control, are widely applied across various industrial sectors due to their simple structure, low cost, and reliable performance. The design of a butterfly valve significantly influences its operating performance, suitability for specific applications, and ease of installation and maintenance. The most common connection types for butterfly valves include wafer type, flanged type, and lug type. Each connection type has a distinct impact on installation and usage. This article offers an in-depth analysis of the structural features, application scenarios, and advantages and disadvantages of these three connection types, helping readers choose the most suitable butterfly valve based on their actual needs.
(1) Structural and Installation Convenience Comparison
Wafer type: simple structure, small footprint, suitable for low-pressure flow regulation; requires precise pipe alignment. Flanged type: suitable for high-pressure, large-diameter pipes, good sealing; but complex and space-consuming installation. Lug type: easy to install, suitable for large diameters; sealing and pressure resistance not as good as flanged type.
(2) Application Condition Comparison
Wafer type: suitable for small to medium diameter and low-pressure pipelines. Flanged type: ideal for large-diameter, high-pressure systems and demanding industrial environments. Lug type: suitable for large-diameter, simple flow control systems; lower sealing and pressure capabilities.
The appropriate butterfly valve connection type should be selected based on specific application needs. For confined spaces and low-pressure scenarios, the wafer type is ideal. For large-diameter, high-pressure systems requiring high sealing performance, the flanged type is more suitable. Where ease of installation is key, especially in large-diameter systems with moderate requirements, the lug type offers a cost-effective solution. Understanding the pros and cons of each valve type helps ensure safe and efficient system operation.
1. Basic Structural Principle of Butterfly Valves
The main components of a butterfly valve include the valve body, valve disc, valve shaft, sealing ring (or seat), and actuator. The disc is typically circular and mounted on the shaft, allowing it to rotate to regulate flow. Compared with other types of valves, butterfly valves are simple in structure, compact in size, and lightweight, making them ideal for large-diameter, low-pressure pipelines. The operating principle involves rotating the disc about the shaft axis to adjust or shut off fluid flow. Butterfly valves are favored for their compact design, fast operation, and low flow resistance, making them especially suitable for large-diameter, low-pressure systems. The connection method plays a critical role in the valve's sealing performance, ease of installation, and suitability for different applications.2. Wafer Type Butterfly Valve
Structural Features:
The wafer type butterfly valve does not have extended flanges at both ends of the valve body. Instead, it is clamped directly between the flanges of two pipeline sections. Bolts fasten the valve and pipe flanges to ensure stable connection. Due to the absence of extended flanges, this type of valve has a simple and compact structure.Installation Method:
Installation is straightforward. The valve is sandwiched between pipe flanges and secured with bolts. Because there are no external flanges, it requires minimal installation space, which is suitable for tight pipeline areas. However, it demands high pipe alignment precision; misalignment may lead to poor sealing, increased friction, and wear.Application Scope:
Wafer type butterfly valves are typically used in low- to medium-pressure and smaller-diameter pipeline systems. They are cost-effective and well-suited for space-limited or budget-constrained applications, such as residential water supply, HVAC systems, and small industrial pipelines.Advantages and Disadvantages:
Advantages include compact size, lower cost, ease of installation, and simple maintenance. However, their pressure capacity is limited, and they require precise alignment during installation, making them unsuitable for high-pressure or harsh environments.3. Flanged Type Butterfly Valve
Structural Features:
The flanged type has standard flanges at both ends of the valve body, facilitating connection with pipeline flanges. The flanges are fastened using bolts, and sealing is typically achieved with rubber gaskets or metal seals to ensure tightness. This structure enables it to withstand higher pressure and more demanding conditions.Installation Method:
Installation requires precise alignment and even bolt tightening between the valve and pipe flanges. The flange faces must be flat, and the sealing rings correctly installed to prevent leakage. The process is more complex and demands more space.Application Scope:
Flanged butterfly valves are widely used in high-pressure, large-diameter, and complex pipeline systems, especially in petroleum, chemical, and power industries. They are suitable for high-temperature, high-pressure, high-flow, and corrosive media applications.Advantages and Disadvantages:
The advantages include high pressure resistance, reliable sealing, and broad applicability. Disadvantages include larger installation space requirements, more complex installation, higher manufacturing costs, and higher maintenance expenses, especially for large diameters.4. Lug Type Butterfly Valve
Structural Features:
Lug type butterfly valves have lugs (ears) at both ends of the valve body, which are used to connect the valve to the pipeline flanges with bolts. Unlike flanged types, they do not have external flanges. The body is connected directly via the lugs.Installation Method:
Installation is relatively simple—just bolt the lugs to the pipeline flanges. This method is particularly suitable for tight spaces and allows for quick installation.Application Scope:
Lug type butterfly valves are used in large-diameter pipelines and simple flow control systems, especially in petroleum and natural gas pipelines under medium to low pressure. They are easy to install and remove and are suitable for applications that do not require very high sealing performance or pressure resistance.Advantages and Disadvantages:
Advantages include simple installation, lower cost, and suitability for large-diameter systems. Disadvantages are slightly weaker sealing performance and pressure resistance compared to flanged types, making them more appropriate for medium- to low-pressure applications with moderate sealing requirements.5. Comparative Analysis
(1) Structural and Installation Convenience Comparison
Wafer type: simple structure, small footprint, suitable for low-pressure flow regulation; requires precise pipe alignment. Flanged type: suitable for high-pressure, large-diameter pipes, good sealing; but complex and space-consuming installation. Lug type: easy to install, suitable for large diameters; sealing and pressure resistance not as good as flanged type.
(2) Application Condition Comparison
Wafer type: suitable for small to medium diameter and low-pressure pipelines. Flanged type: ideal for large-diameter, high-pressure systems and demanding industrial environments. Lug type: suitable for large-diameter, simple flow control systems; lower sealing and pressure capabilities.
6. Conclusion
The appropriate butterfly valve connection type should be selected based on specific application needs. For confined spaces and low-pressure scenarios, the wafer type is ideal. For large-diameter, high-pressure systems requiring high sealing performance, the flanged type is more suitable. Where ease of installation is key, especially in large-diameter systems with moderate requirements, the lug type offers a cost-effective solution. Understanding the pros and cons of each valve type helps ensure safe and efficient system operation.
