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Table of content
1
Understanding the Butterfly Valve
2
Decoding the Butterfly Valve
3
Exploring Butterfly Valve Operation
4
Butterfly Valve Actuation Mechanisms
5
Use of Butterfly Valve
6
Advantages of Butterfly Valves
7
Types of butterfly valve
8
IPC High Performance Butterfly Valves
1. Understanding the Butterfly Valve
A Butterfly Valve is a flow regulating disc Valve, these valve consists of a circular disc or plate built with a stem through the middle or attached offset. When opened, the disc pivots 90° in the valve bore, aligning with the flow, creating a flow path.
Link to LEFLOW
Biggest advantage that the Butterfly Valves offer is they are extremely easy to install, light in weight and relatively compact in size and structure. This compact design also usually makes the initial cost for these Valves relatively lower as compared to other valve designs.
These valves are vital in many industries and especially for water supply and distribution. In this article, we will delve deep into the world of butterfly valves, exploring their construction, working principle, actuation methods, advantages, and their specific application in water supply systems.
2. Decoding the Butterfly Valve
These valve can be distinguished by its simple yet effective design. As part of the quarter-turn valve family, it functions to regulate or completely shut off the flow of a fluid in a pipeline. While valves are often highlighted for their flow control capability, it’s crucial to use them primarily for complete shut-off or full flow applications. This prevents potential damage to the valve disc and maintains optimal sealing properties.
These are widely used in many industries, especially in water systems and pumping stations. They’re popular because they’re simple, compact, affordable and quick to operate.
Understanding Butterfly Valve Components
- Valve Body: The valve body, which fits between the pipe flanges, forms the outermost part of butterfly valves.
- Disc: This is the principal component that regulates fluid flow. The disc is comparable to a gate in a gate valve or a ball in a ball valve.
- Seat: The seat lines the internal valve body and secures the disc in the closed position to achieve complete shutoff.
- Stem: The stem, or the shaft of the valve, connects the disc to the actuation mechanism and transmits the torque through itself.
- Seals: Seals ensure a tight seal during operation and isolate the process media from the valve’s internal components.
3. Exploring Butterfly Valve Operation
The operation of a this valve is relatively straightforward. The valve disc’s rotation controls the fluid flow. When the disc is in the closed position, it blocks the valve bore, and when in the open position, it allows flow by orienting itself perpendicular to the flow direction.
4. Butterfly Valves Actuation Mechanisms
These valves can be actuated or operated in several ways – manual, semi-manual or fully automatic:
- Electric Actuation: This method uses an electric actuator to control the valve with a 4-20mA control signal, ideal for high precision regulation and time-sensitive applications.
- Pneumatic Actuation: We use compressed air for actuation in this method, which also suits high-precision applications.
- Manual Actuation: This method makes use of a handwheel, crank, or lever to operate the valve.
5. Use of Butterfly Valves
These valves are used in various industries for regulating the flow of fluids or gasses within pipelines. Their simple design and quick operation make them perfect for applications requiring fast shut-off or control. This valve rotate a disc to control flow, ensuring low pressure drop and dependable performance. We use them for flow control and reliable shut-off in water treatment, HVAC, chemicals, and various industries.
6. Advantages of Butterfly Valves
- Lightweight and Compact: Their compact design and smaller face-to-face dimension translate to a smaller installation footprint and lower installation costs.
- Low Maintenance Requirements: Their simple design with fewer moving parts reduces their maintenance requirements.
- Fast Acting: A 90° rotation of the handle provides a complete closure or opening of the valve.
- Low Cost: Their simple design often makes butterfly valves a more economical choice compared to other valve types.
- Versatility: You can install Butterfly valves in a wide variety of scenarios, including underground installations.
7. Types of butterfly valve
These Valves can be typically grouped into three basic types:
- Damper
- Centric Design
- Offset Design
Centric Design Butterfly Valve
These valves are commonly called as centric or Resilient-seated Butterfly valves. In these valves, the stem centers in the middle of the valve disc, and the disc centers in the pipe bore. A rubber (resilient) seat makes tight contact with the seal, achieving efficient sealing, which makes them ideal for high-pressure applications.
Offset Design Butterfly Valves
High-performance Butterfly Valves are a popular choice for industrial and commercial use. They’re designed to withstand high temperatures and pressures. In these valves, the shaft doesn’t pass through the seat but through the centerline of the disc. They need pipe flange gaskets when installed between pipe flanges.
Double offset Butterfly Valve
As the name suggests, the double-offset high-performance Butterfly Valves have a disc with two offsets. We position the disc in the center of the pipe bore to enhance sealing ability and reduce wear on the valve. Double offset Butterfly Valves are ideal for systems requiring higher pressure resistance.
Triple offset Butterfly Valves
The triple offset Valve performs reliably in difficult services under harsh conditions. In these Valves, The stem is located behind the disc and offset to one side giving a double-offset to the valve.
IPC is a leading manufacturer of Butterfly Valves. Our valves are durable, light weight and come with increased strength. Proven for their performance, IPC butterfly valves are first choice for industrial and commercial applications.
8. IPC High Performance Valves
IPC High performance Butterfly Valves are best suited to handling water, oil, steam and gas. These valves offer corrosion resistance, cost effectiveness, and lightweight construction, making them an ideal choice for various applications.
Contact us to discuss your requirements of 2-Offset Butterfly Valve. Our experienced sales team can help you identify the options that best suit your needs.
Conclusion
Butterfly valves are indeed an indispensable component in various industries, especially in water supply systems. IPC is a leading manufacturer, supplier and exporter of GGC valve, Ball Valves and Butterfly valves. With our unique design, operational efficiency and multitude of advantages, we offer a reliable and cost-effective solution for regulating fluid flow.
Choosing the wrong type of valve can be detrimental to your operation. There are a few different types of butterfly valves on the market, including the zero offset, double offset, and triple offset. I enlisted the help of Scott Telin, one of Crane’s application engineers and a member of our valves team, to help differentiate between the three offsets. If you aren’t familiar with all the terms mentioned below, be sure to download “The Ultimate Glossary of Valve Terminology”.
Zero Offset
Also known as a concentric design, this is common in general service ‘resilient seated’ or ‘rubber seated’ butterfly valves. The stem and disc are centered in the seat of the valve, all of which are centered in the body of the valve. The disc is in constant contact with the seat.
An advantage of this valve is the media going through the valve will not contact the body, since the seat is constructed as a sleeve or cartridge inside of the body.
Zero offset butterfly valves are used in basic and specialty liquid and gas applications up to 200 PSI and up to 400 deg F. The zero offset butterfly valve can handle chemicals, coatings, food, some solids, and abrasive applications.
The zero offset butterfly valve is available in epoxy coated cast iron and stainless steel with multiple seat materials such as Buna, EPDM, VITON, Teflon, Natural rubber and others.
Double Offset Butterfly Valve
This popular valve is also known as a high performance butterfly valve. This valve has two stems offset from the center. This creates a cam action during the application's process.
- 1st offset: The axis of the shaft is behind the centerline of the sealing point of the disc to seat.
- 2nd offset: The axis of the shaft is eccentric to the center of the valve/pipe line.
The double offset butterfly valve is generally used in:
- Power generation
- Pulp and paper
- HVAC
- Chemical
- Oil and gas
- Water and wastewater treatment
- Shipbuilding
Double offset butterfly valves are available in higher pressures than the zero offset style. The double offset is up to ANSI Class 600 rating in carbon steel, stainless steel, Hastelloy and other body material, with variations of Teflon seats and also Fire Safe design with metal back up seats.
Triple Offset Butterfly Valve
With the triple offset butterfly valve there are three offsets. Two are placed in a similar position to the double offset butterfly valve, while the third offset is the geometry of the seating surface, creating a type of cone shape of the disc and seat. This cone angle, along with the two eccentric shaft offsets, allows the disc to seal against the seat with no friction.
This seat design also allows for uniform sealing, and thus a tight shutoff in a metal seat design. This design is a lower cost, lower torque option (easier to automate), than alternative style metal seated valves.
Triple offsets are generally used in applications similar to gate valves, where a metal seat is required, and tight shutoff and/or quarter turn actuation is desired. Applications like high pressure steam (over 150 PSI), superheated- steam, high temperature gases and oils, high temperature applications are good for this type of valve because a metal seat is required over a soft seat.
The triple offset valve is used in similar industries as the double offset butterfly valve, but in more demanding applications.
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