What is a Triple Eccentric Butterfly Valve?
A triple eccentric butterfly valve, also known as a triple offset butterfly valve, is a type of valve designed to provide high performance and reliability in fluid control systems. It incorporates three offsets in its design to achieve superior sealing capabilities. The three offsets refer to the positioning of the valve stem and the unique geometry of the seating surface. This ensures that the disc only contacts the seat at the final point of closure. This design minimizes friction, extends the valve’s lifespan, and provides a tight, bubble-tight seal even in high-pressure and high-temperature environments. These valves are commonly used in industries like oil & gas, petrochemicals, power generation, and marine, where reliable shut-off is essential.
How Does a Triple Eccentric Butterfly Valve Work?
The triple eccentric butterfly valve operates based on the principle of its three offset axes, which help eliminate rubbing between the disc and the seat during operation. The first offset positions the stem behind the centerline of the sealing surface, allowing for a continuous seat and seal. The second offset shifts the stem away from the bore’s centerline, enabling the disc to disengage from the seat immediately upon opening, reducing wear. The third offset involves a conical sealing surface inclined from the pipe centerline. This ensures that the valve disc only makes contact at the final point of closure. This unique movement provides a non-rubbing, cam-like action that guarantees a tight shut-off, minimizes wear, and allows the valve to handle bi-directional flow with minimal torque. When fully open, the disc is completely clear of the flow path, reducing pressure drop and ensuring unobstructed flow.
Here’s an analysis for the Pneumatic Tri-Eccentric Metal Seat Butterfly Valve:
Features of the Pneumatic Triple Eccentric Butterfly Valve
- Three-Dimensional Eccentric Sealing Structure:
The triple eccentric sealing structure minimizes wear between the seat and the disc. This design ensures a wear-resistant sealing surface, significantly extending the valve’s service life and providing long-term reliability.
- Connection Modes:
The valve can be configured as either a pneumatic wafer type or a pneumatic flange type, allowing for flexibility depending on process requirements. These options make it suitable for a wide range of applications involving different types of pipeline connections.
- Large Caliber Disc with Truss Structure:
The disc of the valve features a truss structure, providing high strength, a large flow area, and minimal flow resistance. This configuration ensures efficient fluid flow and contributes to the valve’s durability.
- Double Direction Pressure Sealing:
The valve adopts a multi-level hard sealing structure that allows for double-direction pressure sealing. This feature enables installation in any direction, without restrictions on flow direction or space limitations.
- Dual Sealing Advantages:
The valve combines the benefits of both metal hard sealing and elastic sealing. It offers excellent sealing performance, corrosion resistance, and a long service life, even in extreme temperature conditions. This ensures effective sealing in both low and high temperatures.
Technical Parameters
| Parameter | Specification |
|---|---|
| Type | Triple eccentric type |
| Nominal Diameter | DN100 ~ DN2000 |
| Nominal Pressure | PN Series: 0.6 MPa, 1.0 MPa, 1.6 MPa, 2.5 MPa, 4.0 MPa; Class Series: Class150, Class300 |
| Connection Mode | Clamp type, flange type |
| Material of Valve Body and Internals | WCB, WC9, CF8, CF8M |
| Top Bonnet Type | Standard type: -60°C ~ +200°C; High temperature type: +200°C ~ +500°C |
| Packing | Teflon asbestos: -5°C ~ +230°C; Teflon: -5°C ~ +230°C; Flexible graphite: -196°C ~ +600°C |
Note: You must pay attention to the temperature and pressure range of each material.
Body, valve parts and material combination of operating temperature and seat leakage
| Body material | WCB, WCC, WC6, WC9, LCB | ||||
| Plate | Material | WCB, WCC, WC6, WC9, LCB | |||
| Handle | Hardfacing alloy | ||||
| Stem material | 3Cr13/304/17–4PH | ||||
| Sealing ring material | Stainless steel + graphite | Stainless steel + reinforced PTFE | Reinforced PTFE | Stainless steel | |
| Packing material | Flexible graphite | Teflon | Teflon | Flexible graphite | |
| Gasket material | XB450/F4/graphite winding gasket | XB450/F4/graphite winding gasket | F4/graphite winding gasket | Graphite winding gasket | |
| Allowable leakage | Grade | VI | VI | VI | V |
| Use standard | GB/T 4213 | ||||
| Use temperature (°C) | WCB, WCC | –20~160 | –20~200 | –20~200 | –20~425 |
| WC6, WC9 | –20~160 | –20~200 | –20~200 | –20~425 | |
| LCB | –20~160 | –45~200 | –45~200 | –45~425 | |
| Body materlal | CF3、CF8、CF3M、CF8M | ||||
| Plate | Material | CF3、CF8、CF3M、CF8M | |||
| Handle | Built-up welding Stellite Alloy | ||||
| Stem material | 20Cr13/304/17-4PH | ||||
| Sealing ring material | Stainless steel + graphite | Stainless steel + reinforced PTFE | Reinforced PTFE | Stainless steel | |
| Packing material | Flexible graphite | Teflon | Teflon | Flexible graphite | |
| Gasket material | XB450/F4/graphite winding gasket | XB450/F4/graphite winding gasket | F4/graphite winding gasket | Graphite winding gasket | |
| Allowable leakage | Grade | VI | VI | VI | V |
| Use standard | GB/T 4213 | ||||
| Use temperature (°C) | -100-500℃ | -45-200℃ | -20-180℃ | -45-500℃ | |
Main External Connection Dimensions
| Nominal diameter DN (mm) | H1 | H2 | H3 | B* | Actuating mechanism | |||
| Wafer | Flange | L | L1 | C | ||||
| 100 | 110 | 406 | 488 | 64 | 127 | 204 | 190 | 200 |
| 125 | 130 | 406 | 542 | 70 | 140 | 260 | 190 | 200 |
| 150 | 150 | 505 | 598 | 70 | 140 | 298 | 225 | 200 |
| 200 | 205 | 567 | 675 | 71 | 152 | 390 | 233 | 300 |
| 250 | 250 | 667 | 775 | 76 | 165 | 458 | 233 | 300 |
| 300 | 270 | 845 | 943 | 83 | 178 | 722 | 285 | 600 |
| 350 | 330 | 983 | 983 | 92 | 190 | 722 | 285 | 600 |
| 400 | 330 | 987 | 1125 | 102 | 216 | 860 | 285 | 600 |
| 450 | 370 | 1027 | 1144 | 114 | 222 | 860 | 285 | 600 |
| 500 | 370 | 1097 | 1235 | 127 | 229 | 860 | 285 | 600 |
| 600 | 455 | 1112 | 1250 | 154 | 267 | 860 | 285 | 600 |
| 700 | 495 | 1230 | 1725 | 165 | 292 | 2500 | 350 | 800 |
| 800 | 597 | 1303 | 1900 | 190 | 318 | 3200 | 350 | 800 |
| 900 | 647 | 1398 | 2045 | 203 | 330 | 3200 | 350 | 800 |
| 1000 | 720 | 1590 | 2290 | 216 | 410 | 3800 | 350 | 800 |
Note: B* Open size can be customized according to user regulrements, the nominal diameter greater than or equal to DN1000 please call.
Applications of Triple Eccentric Butterfly Valves
Triple eccentric butterfly valves (TEBVs) are widely used in several industries due to their robust design and high performance in handling high-pressure and high-temperature conditions. Here are the primary applications:
- Hydroelectric Power Generation:
TEBVs are crucial in hydroelectric plants where high-pressure conditions are common. They manage flow control under these demanding conditions, reducing the risk of cavitation and vibration that could cause mechanical damage.
- Chemical Processing:
In chemical industries, TEBVs control the flow of corrosive or abrasive fluids. The triple-offset design minimizes friction and wear, making these valves suitable for handling aggressive chemicals, ensuring extended service life and reliable shut-off.
- Oil & Gas Industry:
TEBVs are often used in oil and gas pipelines, particularly where tight shut-off and robust performance are needed under high-pressure and temperature conditions. Their triple-offset structure provides a bubble-tight seal, crucial for handling hydrocarbons and other fluids with varying viscosities.
- Water Treatment:
In water treatment plants, TEBVs help control the flow of water and wastewater. They effectively modulate flow rates and maintain tight seals to prevent leakage, even in large-scale applications involving high-pressure pumping stations.
- Refining and Petrochemical Plants:
The valves are used in refining operations where reliable shut-off and flow control are needed for high-temperature, high-pressure, and high-viscosity media. TEBVs provide precise flow control and reduce head loss, improving operational efficiency.
These applications benefit from the unique sealing capabilities of TEBVs, which reduce friction and extend the operational life of the valves. Their reliability in critical situations and ease of operation make them a preferred choice in industries dealing with challenging fluid dynamics and stringent performance requirements.
Advantages of Triple Eccentric Butterfly Valves
1. Excellent Sealing Performance: Triple Eccentric Butterfly Valves (TEBVs) are known for their tight, bubble-tight sealing due to their triple-offset design, which ensures that the disc’s sealing edge moves away from the seat in a non-rubbing, cam-like motion. This minimizes wear on the valve and enhances reliability even under high-pressure conditions, providing virtually zero leakage. This feature is critical in industries such as oil and gas, chemical processing, and power generation, where safety and operational integrity are paramount.
2. High Temperature and Pressure Capabilities: TEBVs can handle a wide range of operating conditions, typically from temperatures as low as -196°C to as high as 650°C, and pressures from Class 150 to Class 1500. These capabilities make them versatile for controlling steam, gases, and other fluids across industries like petrochemical and power generation.
3. Minimal Friction and Long Service Life:
The triple eccentric design of these valves ensures minimal contact between the disc and seat during operation. This significantly reduces friction and wear. Consequently, TEBVs offer an extended service life with lower maintenance requirements. This is particularly advantageous in industries where reducing downtime is crucial.
4. High Flow Capacity and No Dead Zone Design: Due to their unique geometry, TEBVs provide a high flow capacity and maintain effective control even at low degrees of opening. This high control ratio, which can exceed 100:1, makes them efficient for precise flow regulation compared to other butterfly valve types.
5. Low Operating Torque: The design also helps in minimizing the operating torque, reducing the energy requirements for valve actuation. This characteristic supports the integration of automation systems and reduces operational costs over time.
Conclusion
Triple eccentric butterfly valves offer a reliable, high-performance solution for industries with demanding flow control requirements. Their triple-offset design reduces friction and wear, ensures a tight seal, and significantly extends valve life. Therefore, these valves are ideal for use in power generation, chemical processing, oil & gas, and water treatment applications. Thanks to their excellent sealing performance, durability, and ability to handle high-pressure and high-temperature environments, they provide effective solutions.
For a robust and efficient fluid control solution, explore our range of triple eccentric butterfly valves. Contact us today to learn how these valves can enhance your system’s reliability and efficiency.