Butterfly valves are widely used in metallurgy, power and other industrial fields. In order to meet the requirements of various working conditions, butterfly valves have undergone the evolution of single eccentric butterfly valves and double eccentric butterfly valves, and finally have the currently widely used Triple Eccentric Butterfly Valvetterfly .
Working Principle of Triple Eccentric Butterfly Valveerfly Valve
The butterfly valve part mainly consists of packing plate, packing cover, packing, guide sleeve, valve body, butterfly plate assembly, valve stem and lower cover (see Fig. 1). When the butterfly plate is opened and closed, the butterfly plate sealing surface is designed as a diagonal conical sealing surface relative to the axis of the butterfly plate (see Figure 2), which ensures a certain contact angle between the butterfly plate sealing surface and the seat sealing surface (the seat and the valve body are integral), and at the same time can realize the valve plate 360. There is no jamming phenomenon on the sealing surface during the whole closing and opening process, which basically eliminates the friction in the rotating process and greatly reduces the opening moment of the valve.
Sealing structure of Triple Eccentric Butterfly Valveerfly 
Conventional single eccentric butterfly valve only has eccentricity 1 in Figure 2. It is only the rotation axis of the butterfly plate leaving the center of the sealing surface of the butterfly plate. Its characteristic is to avoid the gap in the longitudinal part of the sealing surface, resulting in leakage. But in the process of opening and closing the butterfly plate, there is always friction between the axial part of the sealing surface of the butterfly plate and the sealing surface of the valve seat, which is liable to cause sealing failure and leakage.

Double eccentric butterfly valve, only eccentricity 1, 2 in Figure 2, except that the rotation axis of the butterfly plate leaves the center of the sealing surface of the butterfly plate, the rotation axis adds an eccentricity to the axis of the butterfly plate. Its characteristic is that in the process of butterfly plate rotation, the sealing surface of butterfly plate is separated from the sealing surface of valve, which reduces friction. However, there is still serious friction in the range of 15-200 mm, which is easy to cause leakage.

Triple Eccentric Butterfly Valveerfly valve is based on double eccentric butterfly valve, which adds unique eccentricity 3. The contact angle between the sealing surface of the butterfly valve and the sealing surface of the seat generated by this eccentricity not only uniformly surrounds its circumference, but also equals to a slender wedge, and the sealing line of the longitudinal part of the butterfly plate is quasi-elliptic curve, both of which act as seals at the same time. Compensation effect.
The sealing surface of the Triple Eccentric Butterfly Valveerfly valve butterfly plate is an elliptical cross-section entity with a certain thickness intercepted from the cone (see figure 2). The first eccentricity refers to the relative eccentricity between the equilateral line of the seat sealing surface or the direction of the butterfly plate thickness and the center of the stem (length 1); the second eccentricity refers to the relative eccentricity between the stem and the valve passage (length 2); and the third eccentricity The center is the relative eccentricity (corner) between the center line of the conical sealing surface and the valve center line. AB represents the tangent line at a certain point N of the sealing surface on a certain plane, V represents the velocity direction of the point, and the angle between the velocity direction and tangent AB is p. As shown in Figure 1, no interference occurs in the seal when p is greater than or equal to o. When the velocity is in Y7 direction and the angle < o, the seal interferes.
Noticeable Problems in Selection and Use of Triple Eccentric Butterfly Valveerfly Valve
Applicable occasions: suitable for large caliber, large flow and low pressure difference occasions. Applicable fluids: Applicable to concentrated turbid liquids and fluids containing suspended particles. Sealing Material Selection: Corrosive fluids require the use of corrosive materials.
Application of Triple Eccentric Butterfly Valveerfly Valve in Chemical Plant
The normal control ratio of the Triple Eccentric Butterfly Valveerfly valve is more than 2 times that of the general butterfly valve, and the maximum control ratio can be as high as 100:1, which creates a good condition for the use of the Triple Eccentric Butterfly Valveerfly valve as the control valve. Especially in the case of large caliber, the cost of globe valve is extremely high, and the globe valve can not achieve zero leakage. In the case of emergency shutdown, the cut-off valve must be installed at the side of the globe valve. The Triple Eccentric Butterfly Valveerfly valve can be integrated with regulation and shutdown (to achieve zero leakage), and its economic benefits are very considerable. It has been tested in practice and successfully applied in polyethylene plant. Typical applications: Reactor cooler temperature regulation (as shown in Figure 3), process pipeline for large diameter 18 (1"to 25.4 mm), normal temperature regulation, Triple Eccentric Butterfly Valvetterfly valve as a common control valve, when interlocking occurs, Triple Eccentric Butterfly Valvetterfly valve plays a cut-off role, and completely shut off (zero leakage). At this time, the Triple Eccentric Butterfly Valveerfly valve integrates regulation and shutdown. From the operation of the device, it not only saves the investment cost, but also controls it stably, which brings great economic benefits to the enterprise.
Triple Eccentric Butterfly Valveerfly valve not only has excellent regulation performance, but also uses different sealing forms, which can be applied to the requirements of diversified media. If you have the purchase demand of Triple Eccentric Butterfly Valvetterfly ， please contact us. Beijing Ruito Jiangnan Automatic Control Equipment Co., Ltd. is a manufacturer of angle stroke control valves. It specializes in producing high temperature butterfly valves, Triple Eccentric Butterfly Valveerfly , metal sealed butterfly valves, etc.