What is a flanged butterfly valve? How does it work and how is it classified?

In addition to ball valves, gate valves, air valves, flanged safety valves, and so on, flanged butterfly valves are popular in the valve line. However, for new pipefitters, not everyone understands them clearly. If you want to know what a flanged butterfly valve is, How many types are there? Check out the article from Bao Tin Steel.

What is a flanged butterfly valve?

The flange butterfly valve is also known as the butterfly valve flange end. This is a valve line made from cast iron, steel, plastic, and pressure-resistant stainless steel. The valve body is cast with 2 flanges for easy connection. This valve is controlled by a lever, handwheel, electricity, or compressed air.

In addition to the above name, this valve also has different names. Each place, each person will have their own way of calling the valve. However, as long as the process of finding, buying, and exchanging is simple and effective. Some common names we see are:

• Double Flanged Butterfly Valve
• Flanged Butterfly Valve

Technical specifications of flange butterfly valve

Below are the general parameters of flanged butterfly valves on the market today:

• Size: DN50 – DN900
• Material: Giang, Stainless steel, plastic
• Pressure standard: PN10, PN16, PN25
• Working temperature: 0 ~ 200 degrees C
• Connection type: Flange
• Flange standard: JIS, BS, DIN
• Origin: Korea, China, Malaysia, Europe, Taiwan, Thailand, Japan.

Structure of flange butterfly valve

Similar to other valve lines, the 2-flange butterfly valve also includes parts such as:

• Valve body: Cast iron, stainless steel, and plastic are often used to create the valve body. Special materials help this valve to work well under pressure conditions of 10k- 20k.
• Valve disc: It is also made of cast iron, steel, and stainless steel. The valve disc will be in direct contact with the fluid. Therefore, it is necessary to clearly understand which system the valve is used in. From there, choose a butterfly valve with a suitable valve disc.
• Valve shaft: It is usually made of stainless steel and high-strength steel. Helps connect the valve disc to the transmission part, supporting the valve opening and closing process.
• Sealing gasket: It helps seal the space between the valve body and the valve flap. Limits leakage and noise. This gasket is usually EDPM rubber, Viton rubber, or Teflon (PTFE).
• Actuator: This is the part that creates force on the valve shaft to open or close the valve. This can be a handwheel, lever, electric controller, or pneumatic controller.

>> You can see more about flanged ball valves to see the difference in structure between these two types of valves.

Operating principle of the flange butterfly valve

The operation of this butterfly valve is similar to other industrial valves. It mainly depends on the rotation ability of the valve shaft. Specifically:

When the valve shaft is not affected, the valve disc will fit tightly to the valve body. In other words, it is in a completely closed state, and the fluid cannot pass through.

Conversely, when the valve shaft is affected (by handwheel, lever, electricity, or compressed air), it will pull the valve disc. It will rotate 90 degrees or less to create a gap for the fluid to pass through.

When you want to close the valve, you just need to stop applying force to the shaft, and the valve will return to the closed state. The rubber gasket will help seal the valve body and valve disc tightly and block the flow of fluid. Specifically, you can turn the steering wheel in the opposite direction compared to when opening/pushing the valve handle in the opposite direction, turning off the electric switch, or turning off the pneumatic switch.

It can be seen that you are completely in control when operating the flanged butterfly valve. Depending on the needs, we can control the opening and closing of the valve or the large or small level of the fluid flow.

Flange butterfly valve classification

Double-flange butterfly valves are very diverse in materials as well as operating methods. These are also factors that help classify this type of valve. Specifically:

Classification by production material

Cast iron flanged butterfly valve: Cast iron here is usually ductile iron. It has good load-bearing capacity, impact resistance, and heat resistance. Normally, cast iron butterfly valves will be coated with an additional layer of epoxy to limit rust. The price of cast iron flange valves is also quite reasonable, so it is very popular.

Stainless steel flanged butterfly valve: The main stainless steel used is Inox 304 and Inox 316. With a beautiful shiny appearance, excellent hardness, and less rust, stainless steel flanged butterfly valves are trusted in many large and small systems. However, because of many outstanding advantages, this type of butterfly valve also has a higher price than valves made from other materials.

Plastic flanged butterfly valve: As the name suggests, the main material here is plastic (PVC, uPVC,…). It can work under PN16 pressure and at a temperature of 95 degrees Celsius. The valve is quite sturdy, light, and easy to move and install. Flanged plastic butterfly valves are also less corrosive, so they are suitable for gasoline and oil pipelines. Because they are made of plastic, this valve is quite cheap. However, its lifespan is not as long as other types of valves.

The material of the flange will directly affect the pipe it connects to. Because only the right material when connecting will work well and ensure safety. In addition, it also affects the price of that valve. You can read more articles about the price of steel and stainless steel flanges for more interesting knowledge.

Classification by operating method

Flange handwheel butterfly valve

This valve operates through a handwheel (handwheel). When the handwheel is turned clockwise, the valve will open and vice versa, the valve will close. This handwheel flange butterfly valve is operated manually. This helps technicians easily monitor and handle problems quickly when they occur.

Flange Lever Butterfly Valve

This valve is also manually controlled. Just hold the lever and move it left or right at a sufficient angle to close or open the valve. It can be seen that controlling the valve is very easy and quick. In addition, the cost of buying a flanged lever butterfly valve is also very affordable compared to many other types of flanged valves.

Electric control flanged butterfly valve

This valve is equipped with an actuator. It will receive electrical energy and convert it into mechanical energy for the valve to operate. The voltage levels used are 24V, 110V, 220V, 380V… The valve opens and closes very quickly. It can operate with many devices at the same time. This valve can even be controlled remotely, so the valve can be operated anywhere.

Pneumatically controlled flanged butterfly valve

The main energy used to operate this type of butterfly valve is compressed air. There will be a pneumatic actuator on the valve body. It will convert compressed air into mechanical energy to control the valve to open or close. We only need to supply an appropriate amount of compressed air for the valve to operate. Similar to the electric control valve, this valve can be installed in many different locations. However, its installation cost is quite high because we have to buy additional equipment such as air compressors, air pipes, gauges, etc. Therefore, only large systems that require high productivity use this flanged butterfly valve.

Popular types of flanged butterfly valves

If you have a flanged butterfly valve catalog, you will now have many different types of flanged butterfly valves. They come from many brands with a variety of sizes and specifications. However, in Vietnam, there will only be a few lines of 2-flange butterfly valves that are widely used. You can refer to:

Wonil Korea Flange Handwheel Butterfly Valve

This is also one of the valve brands that is very popular with Vietnamese users. This brand has fully applied advanced technology and international standards to its valve production and assembly process. Below are some parameters of Wonil flanged butterfly valves:

• Size: DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350, DN400.
• Material: Cast iron body, stainless steel wing
• Gasket: EPDM
• Operation method: Handwheel (steering wheel)
• Connection type: Flange
• Connection standard: JIS, BS
• Pressure: PN10, PN16
• Working temperature: 80 degrees C

YDK Korea Flange Lever Butterfly Valve

This is currently one of the leading prestigious industrial valve manufacturing brands in Korea. Manufacturer YDK has applied many advanced technologies and modern machinery to produce quality valve products. Therefore, valves from this brand are highly appreciated, including flanged butterfly valves. You can see more technical specifications of this valve:

• Size: DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350
• Material: Cast iron body, stainless steel wing
• Gasket: NBR, VITON, EPDM, PTFE
• Operation method: Lever
• Connection standard: BS
• Connection type: Flange
• Pressure: PN10, PN16
• Working temperature: 80 degrees C

China JS Flange Butterfly Valve

This is one of the major valve manufacturers from China. The products from here are guaranteed quality, and the price is also very affordable. In particular, flanged butterfly valves always ensure a simple structure and a relatively long life.

• Size: DN50, DN65, DN80, DN100, DN125, DN150
• Material: Cast iron body, stainless steel wing
• Gasket: NBR, EPDM
• Operation method: Handwheel (steering wheel)
• Connection type: Flange
• Connection standard: BS, JIS, DIN
• Working pressure: PN16
• Working temperature: Max 120 degrees

It can be seen that this type of valve is widely used in our country. In addition to Korea and China, we also have Japanese, Taiwanese, and Malaysian flanged handwheel butterfly valves… Each type of valve will have its advantages. Therefore, you need to know clearly which type you need and what the technical parameters are to buy the right valve.

Above is information about flanged butterfly valves as well as their diversity. Please contact Bao Tin Steel immediately if you need help and receive a quote for this flanged valve! 0932 059 176.