As a seasoned supplier of centre – pivoted butterfly valves, I’ve had the privilege of witnessing firsthand the diverse applications and characteristics of these essential industrial components. Centre – pivoted butterfly valves are widely used in various industries due to their simplicity, cost – effectiveness, and versatility. However, not all centre – pivoted butterfly valves are created equal. In this blog, I’ll explore the differences between different types of centre – pivoted butterfly valves. Centre-pivoted Butterfly Valve
Soft – Seated Centre – Pivoted Butterfly Valves
Soft – seated centre – pivoted butterfly valves are perhaps the most common type. These valves are equipped with a soft sealing material, typically made of materials such as EPDM, NBR, or PTFE. The soft seat provides excellent sealing performance, often achieving bubble – tight shut – off. This makes them ideal for applications where leakage prevention is critical, such as in the water treatment industry, food and beverage processing, and HVAC systems.
One of the key advantages of soft – seated valves is their relatively low torque requirement. The soft seat allows the disc to rotate easily, requiring less force to open and close the valve. This not only reduces the energy consumption but also makes it easier to automate the valve using smaller actuators.
However, soft – seated valves also have some limitations. The soft sealing material is more susceptible to wear and damage, especially when used in abrasive or high – temperature applications. The temperature range for soft – seated valves is usually limited, typically between – 20°C to 120°C, depending on the material. Also, the soft seat may not be suitable for applications with highly corrosive media, as some chemicals can degrade the soft sealing material over time.
Metal – Seated Centre – Pivoted Butterfly Valves
In contrast to soft – seated valves, metal – seated centre – pivoted butterfly valves are designed for more demanding applications. These valves use a metal – to – metal sealing mechanism, which provides better resistance to high temperatures, abrasion, and corrosion. Metal – seated valves can withstand extreme temperatures, often up to 700°C or even higher, depending on the material and design.
They are commonly used in industries such as power generation, oil and gas, and petrochemicals, where the valves need to operate in harsh environments. For example, in a power plant’s high – temperature steam system, metal – seated butterfly valves can provide reliable shut – off and control.
The construction of metal – seated valves is more robust. The metal seats and discs are often made of high – grade stainless steel, alloy steels, or other specialty metals. This gives them a longer service life compared to soft – seated valves, especially in applications with high – velocity flow or abrasive particles.
But metal – seated valves also come with some drawbacks. They generally require higher torque to operate, as the metal – to – metal contact creates more friction. This means larger and more powerful actuators are needed for automation. Additionally, achieving a bubble – tight shut – off with metal – seated valves can be more challenging compared to soft – seated valves, as even a small amount of wear on the metal surfaces can lead to leakage.
Double – Offset Centre – Pivoted Butterfly Valves
Double – offset centre – pivoted butterfly valves represent an improvement over the traditional single – offset design. In a double – offset valve, the shaft is offset from both the centre of the disc and the centre of the pipe. This offset design reduces the contact between the disc and the seat during the opening and closing process, minimizing wear and tear on the seat.
The reduced friction also results in a lower torque requirement compared to single – offset valves, especially in larger valve sizes. Double – offset valves are suitable for a wide range of applications, including both high – pressure and low – pressure systems. They are commonly used in the chemical, pharmaceutical, and pulp and paper industries.
The double – offset design also provides better sealing performance. As the valve closes, the disc is gradually pressed against the seat, creating a tight seal. This design can achieve a high degree of shut – off, even in applications with demanding pressure differentials.
Triple – Offset Centre – Pivoted Butterfly Valves
Triple – offset centre – pivoted butterfly valves are the most advanced type of centre – pivoted butterfly valves. In addition to the two offsets in a double – offset valve, a third offset is introduced in the conical shape of the seat and disc. This unique design eliminates any contact between the seat and the disc during the opening and closing process, except at the final sealing position.
The result is a valve with extremely low wear and tear, long service life, and excellent sealing performance. Triple – offset valves can achieve bubble – tight shut – off even in high – pressure and high – temperature applications. They are often used in critical applications, such as in offshore oil and gas platforms, where reliability and safety are of utmost importance.
However, the complex design of triple – offset valves makes them more expensive to manufacture compared to other types of centre – pivoted butterfly valves. They also require more precise installation and maintenance to ensure optimal performance.
Wafer – Style vs. Lug – Style Centre – Pivoted Butterfly Valves
Apart from the different sealing and offset designs, centre – pivoted butterfly valves also come in different body styles, mainly wafer – style and lug – style.
Wafer – style butterfly valves are designed to be installed between two flanges. They are lightweight and compact, making them suitable for applications where space is limited. Wafer – style valves are relatively easy to install and remove, as they do not require additional bolts or nuts. However, they rely on the flanges of the pipeline for support, and in some cases, may require a more accurate alignment during installation.
Lug – style butterfly valves, on the other hand, have threaded inserts (lugs) on the valve body. These lugs allow the valve to be installed between two flanges using bolts that pass through the lugs. Lug – style valves provide more flexibility in installation, as they can be installed in a pipeline where one side needs to be removed for maintenance without affecting the other side. They are more suitable for applications where the valve needs to be isolated frequently.
Conclusion
In conclusion, the different types of centre – pivoted butterfly valves offer a wide range of options to meet the diverse needs of various industries. Soft – seated valves are great for applications where low – cost and good sealing at normal temperatures are required. Metal – seated valves are the go – to choice for high – temperature and abrasive environments. Double – offset and triple – offset valves provide better performance in terms of wear resistance, torque requirements, and sealing. Wafer – style and lug – style valves offer different installation advantages.
Centre-pivoted Butterfly Valve As a supplier, I understand the importance of choosing the right valve for your specific application. Whether you need a valve for a simple water – flow control or a critical high – pressure, high – temperature system, we have the expertise and product range to meet your needs. If you’re looking for high – quality centre – pivoted butterfly valves or need advice on valve selection, I encourage you to reach out to our team. We’re here to help you make the best decision for your project.
References
- "Butterfly Valves: Design, Selection, and Installation" by Valves World Magazine
- "Handbook of Valves" by Valve Manufacturers Association
- Industry white papers on butterfly valve technology from leading valve manufacturers
Zhejiang Sunawei Valve Co., Ltd.
As one of the most professional centre-pivoted butterfly valve manufacturers and suppliers in China, we offer a wide range of valves with superior quality. Please feel free to wholesale high quality centre-pivoted butterfly valve at competitive price from our factory. We also accept customized orders.
Address: Anfeng Industrial, Oubei Town, Wenzhou City, Zhejiang, China
E-mail: snv@sunawevalve.com
WebSite: https://www.sunay-valves.com/
