The Development and application of three eccentric butterfly valve

       Chinabase is able to offer custom, cost-optimized solutions in accordance with customer drawings - such as ready-to-install machine parts and profiles - in addition to our standard products. Our internal Application Technology department and field staff are happy to provide free advice on custom solutions.

     Guides for roller chains that comply with DIN 8187 and round link chains that comply with DIN 766 and DIN 764.

Our guides are range of : Steel C profiles , Shaft Collar，Chain guides for roller chains , Lifting Chain，Chain guides for round link chains , Belt guides,power transmission equipment.

       Three eccentric butterfly valve and its scope of application canwithstand up to 2500 pounds, low temperature resistance to -196 ℃, 700 ℃, seal leakage, control ratio reached 0 above 100:1.That is to say, in a variety of harsh, key process control line,whether the valve or control valve, as long as the selection of appropriate, now can safely use butterfly valve, and low cost.

Drive Line 

      Closely related to performance butterfly valve and its continuouseccentric, evolution, development. In order to meet therequirements of various conditions, the butterfly has gone through the evolution from concentric to the single eccentric, eccentricand three eccentric. Development and application of the evolution process of butterfly valve of the 3 eccentric butterfly valve andintroduced briefly as follows

      一.Butterfly classification

     The structural characteristics of the butterfly valve 1, concentricbutterfly valve stem axis, the disc center, central body in the same position. Has the advantages of simple structure,convenient manufacture. Rubber lined butterfly valve that is common in this category. Due to the shortcomings of the butterfly plate and the valve seat is always squeeze, scratch state, from the resistance, wear faster. To overcome the squeeze, scratch,to ensure the sealing performance, seat basically adopts elastic material such as rubber or PTFE, but also result in the use of limited by temperature, which is why people think the traditionalhigh-temperature butterfly valve is not of reasons.

      二.A single eccentric butterfly valve to squeeze, address concentric butterfly valve and valve seat of the resulting in a single eccentric butterfly valve, the structural characteristics of the stem axis deviated from the center of the disc, so that the disc is no longer a rotary axis, dispersion, reduce the excessive squeezingis connected with the valve seat of the butterfly plate. But because the scratch phenomenon single eccentric structure in the switching process of the valve disc with the valve seat has not disappeared, very much the same, and in the application of the concentric butterfly valve is not used.

      三.Double eccentric butterfly valve of the most widely, the double eccentric butterfly valve in a single eccentric valve on the basis offurther improvement of molding is used at present. Its structural characteristics both in the stem axis deviation from the center of the disc, but also deviate from the body center. The effect of the double eccentric valve can be opened immediately after the discfrom the valve seat, substantially eliminating the butterfly plate and valve seat unnecessary over extrusion, scratching phenomenon, reduce the resistance from the open, reducing thewear, improve seat life. Significant reduction of scratching, but also makes double eccentric butterfly valve metal valve seat can also be used, improved valve in the field of high-temperature applications. But because of its position of sealing structure sealing principle is, that the butterfly plate and valve seat sealing surface for line contact, deformation effect, so the closed position demanding sealing with the valve seat disc extrusion caused byelastic (especially metal seat), the ability of low pressure, which iswhy people think the traditional butterfly valve not resistant to high voltage, the leakage of reasons.

     四.Three eccentric butterfly valve to high temperature, you must use the seal, but the leak volume; to zero leakage, you must use the soft seal, but not high temperatures. In order to overcome this contradiction double eccentric butterfly valve, and a valve on the third eccentric. The structural characteristics of the stem axisposition of the eccentric double eccentric butterfly board at the same time, the sealing surface of the conical cylinder axis deviation in the body axis, that is to say, the sealing section after the third eccentric, the disc is no longer is really round, elliptical,but the shape of the sealing surface and thus also asymmetric,side in the center of the body line, the other side of the body is parallel to the center line. The biggest characteristic of the thirdeccentric is fundamentally changed the seal structure, location is not sealed, but the torque seal, it is not dependent on the elastic deformation of the valve seat, but to rely completely on the valve seat surface contact pressure to achieve the sealing effect, so one has solved the problem of zero leakage metal seat, and because of the contact surface pressure and medium pressure is proportional to the resistance, high pressure and high temperature can be smoothly done or easily solved.