How the Triple Eccentric Butterfly Valve works?

What is a triple offset butterfly valve?

The butterfly valve has a very compact design belonging to the quarter family. It’s lightweight, easy to operate, and has lower torque. It’s considered a top choice for critical and severe applications. Triple offset butterfly valve design achieves zero leakage on metal-to-metal contact. The hard facing seat eliminates the rubbing between the seat and seal ring through the flow path to extend the cycle life. Its uniform sealing can operate more frequently, and open and close quickly.

Triple eccentric butterfly valve photo

Triple eccentric butterfly valve work

1. As the centre line of the valve seat is offset from the centre line of the valve body by forming a β angle on the basis of the double eccentric butterfly valve, it makes the sealing surface of the butterfly plate immediately detach from the sealing surface of the valve seat during opening and closing, while it only contacts and compresses the sealing surface of the valve seat at the moment of closing.
2. When fully opened, a gap is formed between the two sealing surfaces that is identical to that of the double eccentric butterfly valve. The design of the eccentric butterfly valve completely eliminates mechanical wear and abrasion between the two sealing surfaces, making the sealing performance and service life of the butterfly valve greatly improved.
3. When the valve is closed, the sealing ring is extruded by the sealing surface of the valve body and the butterfly plate, resulting in elastic deformation in two directions. The sealing surface is subjected to outward tension in the direction of the long axis and inward compressive stress in the direction of the short axis, with the long and short axes producing elastic deformation in different directions, thus enabling the sealing force between the sealing surfaces of the valve to gradually reach a higher value.
4. The unique eccentric combination utilises both the cam effect and the complete elimination of friction, thus achieving friction between the valve seat and the seal on the valve plate during the 90° stroke of the valve, removing the possibility of wear and leakage.

Benefits of a Triple Offset Butterfly Valve

The combination of these three offsets gives this valve its key benefits which are as follows:

• Geometric Design: The design of the sealing components takes up a right-angle cone shape. Resulting in a cam-action and right-angled design where the sealing components are never in contact until their final degree of closing. Thus, enabling a repeatable sealing and an extended valve life because of its friction-free nature. In addition, the friction-free stroking throughout the valve allows for a relatively lower torque actuator to be used in operating this type of valve. Such a design makes it ideal for automation.
• Metal-to-Metal Seal: Because of the frictionless sealing mechanism, triple offset butterfly valves use a metal-to-metal seal. This enables a tight shutoff in high-pressure and high-temperature systems. Applications that use friction in sealing often use elastomers or soft material for the valve trim, which may deteriorate with increasing temperature or when the valve is subjected to corrosion. But with the triple offset, corrosion-resistant alloys can serve for both the valve disc and seat, to deliver zero leakage performance.
• Absence of Cavities: In a triple-offset valve, there are no cavities between sealing components. Therefore, there is no room for debris to clog and disrupt the sealing mechanism, unlike gate and ball valves. This minimizes maintenance costs and extends the valve life.

It is a high performance butterfly valve that can be used in high temperature and high pressure environment. It is widely used in metallurgy, steel, electric power, petroleum, chemical industry, heating, air, gas, combustible gas, municipal water supply and water supply and drainage etc., as a stop or regulating medium flow.
If you need a quotation for a triple eccentric butterfly valve, feel free to contact VALTECCN: professional industrial butterfly valve manufacturer and supplier from China!