Triple Eccentric Butterfly Valve

Triple Eccentric Butterfly Valve

Triple eccentric butterfly valve is widely used in metallurgy, electric power, petrochemical, water supply and drainage and municipal construction and other industrial pipelines with medium temperature≤425℃, for regulating the flow and carrying off the fluid. The material is divided into: cast iron, cast steel, stainless steel, three eccentric butterfly valve to high temperature resistance, must use hard seal, but the leakage volume is large; to zero leakage, must use soft seal, but not high temperature resistance. To overcome this contradiction of double eccentric butterfly valve, the third eccentric butterfly valve is also carried out. The structural feature is that while the double eccentric stem axis position is eccentric, the conical axis of the butterfly plate sealing surface is skewed to the body cylindrical axis, that is, after the third eccentric, the sealing section of the butterfly plate is no longer true circle, but ellipse, and its sealing surface shape is thus asymmetric, one side is skewed to the body center line, and the other side is parallel to the body center line. The most important feature of the third eccentric is that it fundamentally changes the sealing structure, which is no longer position sealing, but torsion sealing, that is, it does not rely on the elastic deformation of the valve seat, but completely relies on the contact surface pressure of the valve seat to achieve the sealing effect, thus solving the problem of zero leakage of the metal valve seat at one stroke, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance is also solved.

Zhejiang Huachi valve in the design process, special consideration in the application of the field of control, make full use of the sealing principle of the three eccentric butterfly valve, so that the butterfly plate does not scrape the valve seat when the valve is opened and closed, the torque of the stem through the butterfly plate directly to the sealing surface, that is, almost no friction between the butterfly plate and the valve seat, thus eliminating the common phenomenon of jumping when opening ordinary valves, eradicating the low opening range of the valve due to friction and other unstable factors caused by the inability to control the phenomenon, that is, the dead zone (no sense band), which means that Huachi valve can almost start from 0 degrees into the adjustable area, until the dead zone (no sense band). This means that the Hatch valve can enter the adjustable area from 0 degrees to 90 degrees, and its normal control ratio is more than 2 times that of normal butterfly valves, and the highest control ratio can be more than 100:1. This creates good conditions for the use of HCH control valve, especially in large diameter, the cost of the shut-off valve is very high, in addition, the shut-off valve can not achieve zero leakage, in the need for emergency shutdown conditions, the shut-off valve must be installed on the side of the shut-off valve, and HCH valve set control and shut-off in one, its economic benefits are extremely considerable.