Rubber-lined butterfly valves and rubber sealed butterfly valves are common types of industrial valves. They are used in many industries. Both valves use rubber as the sealing material. However, they differ in their structural design, suitable environments, and sealing performance. This article compares the two butterfly valve types in detail, including their characteristics, working principles, applications, and selection guidelines.
Structure and Features of Rubber-lined Butterfly Valves
The main feature of rubber-lined butterfly valves is that the inner surface of the valve body is integrated with a rubber lining through a high-temperature vulcanization process. This structure improves the valve's corrosion resistance and significantly enhances its performance in harsh environments.
1. High Corrosion Resistance
The valve body's inner surface is lined with rubber or plastic. This lining resists corrosion from strong acids, alkalis, and other corrosive fluids. Therefore, rubber-lined butterfly valves are especially suitable for industries like chemicals, petrochemicals, and pharmaceuticals that deal with corrosive liquids.
2. Sealing Performance
Rubber-lined butterfly valves can be designed with full rubber lining or partial rubber lining. In full rubber-lined valves, both the valve plate and body are lined with rubber. Partial rubber-lined valves only line certain parts, such as the valve plate or body. Full lining provides better sealing performance and is suitable for highly corrosive environments.
3. High Temperature and Pressure Performance
Rubber-lined butterfly valves can generally withstand higher working temperatures. Some designs can handle temperatures up to 150°C. The rubber lining does not degrade or fail at high temperatures, ensuring the valve stays stable during long-term use.
4. Wear Resistance
The rubber lining in rubber-lined butterfly valves provides good wear resistance. These valves are suitable for fluids that contain particles, preventing the valve body from being damaged by particle abrasion.
5. Types of Rubber-lined Butterfly Valves
Full Rubber-lined Butterfly Valve: The entire valve body and valve plate are lined with rubber. This type is suitable for highly corrosive environments.
Partial Rubber-lined Butterfly Valve: Rubber is applied only to certain parts of the valve plate or body. This type is suitable for moderately corrosive environments.
Structure and Features of Rubber Sealed Butterfly Valves
Rubber sealed butterfly valves feature an independent rubber seat (seal ring). This seat is installed inside the valve body and works with the valve plate. The structure of these valves is simpler, making them suitable for applications where corrosion resistance is not a major concern.
1. Sealing Design
Rubber sealed butterfly valves use an independent rubber seat installed in the valve body. During operation, the valve plate tightly contacts the seal seat, providing a reliable sealing effect. The rubber seat can be replaced when necessary to match different fluids and environmental conditions.
2. Flexibility and Applicability
Due to their simple structure, rubber sealed butterfly valves can meet a wide range of working conditions. The sealing material can be made from various types of rubber, such as natural rubber, nitrile rubber, or neoprene. These materials offer good sealing performance and work in a broad temperature range.
3. Cost-effectiveness
Compared to rubber-lined butterfly valves, rubber sealed butterfly valves are less expensive to manufacture and maintain. They are a more economical and efficient choice for applications that do not involve highly corrosive fluids, such as general water treatment, air pipelines, and HVAC systems.
4. Temperature and Pressure Limitations
The rubber sealing material in rubber sealed butterfly valves typically has a temperature and pressure limit. These valves generally work within a range of -10°C to 120°C, making them suitable for fluids with lower or moderate temperatures.
5. Types of Rubber Sealed Butterfly Valves
Soft-seal Rubber Sealed Butterfly Valve: Uses soft rubber as the sealing material. This type is suitable for sealing general fluids.
Hard-seal Rubber Sealed Butterfly Valve: Uses hard rubber to improve sealing performance. This type is suitable for applications where a higher sealing performance is needed.
Key Differences Between Rubber-lined and Rubber Sealed Butterfly Valves
FeatureRubber-lined Butterfly ValveRubber Sealed Butterfly ValveSealing MaterialIntegrated rubber lining, providing high corrosion resistanceIndependent rubber seat, suitable for general applicationsApplicable EnvironmentStrong acids, strong alkalis, and highly corrosive fluidsGeneral fluids, moderately corrosive environmentsTemperature RangeTypically -10°C to 150°CTypically -10°C to 120°CWear ResistanceHigher, suitable for fluids with particlesLower, suitable for clean fluidsApplicable IndustriesChemicals, petrochemicals, pharmaceuticalsWater treatment, air pipelines, HVAC, etc.
Selection Guide for Rubber-lined and Rubber Sealed Butterfly Valves
When choosing between rubber-lined butterfly valves and rubber sealed butterfly valves, consider the following factors.
Nature of the Fluid: If the fluid is highly corrosive (e.g., strong acids or alkalis), it is better to choose a rubber-lined butterfly valve. Its high corrosion resistance will protect the valve and pipeline system.
Working Environment Temperature: For high-temperature environments (over 120°C), a rubber-lined butterfly valve is typically a better choice, especially those with high-temperature resistant linings.
Sealing Performance Requirements: If the sealing performance needs to be very high, especially in fluids with high temperatures or corrosive properties, a full rubber-lined butterfly valve should be selected. If the sealing requirements are not as strict, or the working temperature is lower, a rubber sealed butterfly valve may provide a more cost-effective solution.
Presence of Particles in the Fluid: Rubber-lined butterfly valves are better for handling fluids with particles due to their higher wear resistance. Rubber sealed butterfly valves are better suited for clean fluids.
Maintenance and Considerations During Use
Whether using rubber-lined butterfly valves or rubber sealed butterfly valves, the sealing component is the key part of the valve. During use, any wear, aging, or damage to the sealing part will lead to reduced sealing performance and may cause leakage. In particular, during installation, if the rubber or lining materials become deformed, cracked, or aged, it can affect the valve's normal operation. Therefore, regular inspections and timely replacement of sealing materials are essential to ensure long-term stable valve operation.
Conclusion
Both rubber-lined butterfly valves and rubber sealed butterfly valves have unique features. They are suitable for different operating conditions and environments. Rubber-lined butterfly valves, with their excellent corrosion resistance and sealing performance, are ideal for handling highly corrosive fluids like strong acids and alkalis. In contrast, rubber sealed butterfly valves, with their cost-effectiveness and wide applicability, perform well in many fluid control applications. When selecting a valve, consider the characteristics of the fluid, working conditions, and sealing requirements to choose the most suitable type of valve. This will ensure the reliability and efficiency of the fluid control system.
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