ZECO company currently mainly supplies the following five forms of butterfly valves, including triple offset butterfly valve, LUG butterfly valve, high-performance butterfly valve, metal seated butterfly valve, and double offset butterfly valve. Each is designed and produced according to customers' needs in the industry. We promise the product quality and the competitive price of our butterfly valve.
ZECO double eccentric(double offset) butterfly valve: the design upgrades from a single eccentric butterfly valve and double eccentric butterfly valve is currently the most commonly used butterfly valve. The feature is that the stem offset from the centerline of the disc and centerline of the valve body. The double eccentric effect makes the disc to be quickly disengaged from the valve seat after opening, which greatly eliminates unnecessary over-squeezing and scraping of the disc and valve seat, decreases the opening torque, reduces wear and improves the service life of it. The scraping is greatly decreased, and the double eccentric butterfly valve is also available for metal to metal seats, which improves the application of the butterfly valve in high-temperature working conditions. However, the sealing design is of position sealing structure, that is, the contact surface of valve disc and seat is in line contact, and the sealing relies on elastic deformation created by the disc pressing valve seat, so it has strict requirement of valve closure (especially for metal to metal seat), the bearing only suitable for low pressure, which is why people think that butterfly valves are not suitable for high-pressure and low leakage application.
ZECO triple eccentric(triple offset) butterfly valve: to make the valve suitable for a high-temperature application, metal to metal seal should be used, but there will be a leakage in the meantime. In order to achieve zero leakage, soft material for sealing should be considered, but obviously soft seal is not suitable for high-temperature applications.Therefore the third eccentricity of the butterfly valve was designed to make up the shortcoming of a double eccentric butterfly valve. The feature is that the conical axis of the contact surface of the valve disc is deflected to the axis of the valve body, which means, after the third eccentricity, the disc sealing is not eccentric at the axial position of the double eccentric valve stem. In addition, the sealing is an ellipse and asymmetrical in the meantime, one side of sealing is inclined to the body center line and the other side is parallel to it. The biggest difference of double eccentric and triple eccentric butterfly valve is that the sealing design is not a positional seal but a torsion seal, which means, triple eccentric butterfly valve achieves sealing by sealing surface pressure of valve seat. Triple eccentric butterfly valve allows the metal to the metal seat to achieve zero leakage and makes the butterfly valve suitable for medium pressure, high pressure and high-temperature application.