Pneumatic valve adjustment during the development process of the formation of the classification

the third time that the biggest characteristic of eccentric fundamentally changed the seal structure and seal position is no longer, but the torque seal, which is not dependent on the elastic deformation of pneumatic valve seat, but entirely on pneumatic seat contact pressure to achieve sealing effect, thus solve the metal pneumatic seat the problem of zero leakage, and because of the contact pressure and the medium pressure is proportional to the resistance to high pressure high temperature is solved.

a, concentric butterfly pneumatic valve structure features of this kind of butterfly pneumatic valve for pneumatic valve stem axis, the butterfly plate center, center of ontology in the same position. Simple structure, convenient manufacturing. Rare line with rubber butterfly pneumatic valve which belongs to and so on. Defect is due to the butterfly plate remain the state of extrusion, scraping and pneumatic valve seat, is apart from the big, fast wear. To overcome the extrusion, scratches, ensure the sealing performance, pneumatic seat basically use the elastic material such as rubber or ptfe, but also on the use is limited by temperature, which is why people think butterfly on radical pneumatic valve is not the cause of the high temperature resistant.
2, single eccentric butterfly pneumatic valve
to solve the problem of concentric butterfly butterfly plate of pneumatic valve and pneumatic seat extrusion problems happened, the single eccentric butterfly pneumatic valve and its structure characteristics of pneumatic valve rod axis deviation from the center of butterfly plate, so that the butterfly plate up and down side is no longer a rotary axis, scattered, reduced the butterfly plate up and down side and use. caking of pneumatic seat. But as a result of single eccentric structure butterfly plate in the process of the whole pneumatic valve switch with pneumatic seat scratches phenomenon did not disappear, application scope and concentric butterfly pneumatic valve is the same, is not much. Three pneumatic valve, double eccentric butterfly

single eccentric butterfly pneumatic valve on the basis of further improve molding is currently the most widely used double eccentric butterfly pneumatic valve. Its structure characteristics is in the center of the pneumatic valve stem axis deviation both disc and deviating from the center of ontology. The effect of the double eccentric butterfly plate can immediately after pneumatic valves are open from pneumatic valve seat, greatly eliminates the butterfly plate and pneumatic seat unnecessary phenomenon of excessive extrusion, scratches, reduce the opening distance, reduces the abrasion resistance, improve the pneumatic seat life. Scraping slash, but also makes the double eccentric butterfly pneumatic valve can also use a metal pneumatic valve seat, improves the butterfly pneumatic valve in the field of high temperature applications. But position because its sealing principle of sealing structure, namely the butterfly plate and pneumatic valve seat sealing surface of line contact, through the butterfly plate extrusion pneumatic seat elastic deformation caused by the high requirement of sealing effect, therefore, to the closed position, Especially the metal pneumatic seat bearing capacity is low, this is why people don't think butterfly pneumatic valve on radical resistance to high pressure, a large quantity of leakage.
four, three eccentric butterfly pneumatic valve
to use hard seal, high temperature resistant, necessary but leakage; To zero leakage, must use soft seal, but it is not resistant to high temperature. In order to overcome the double eccentric butterfly pneumatic valve this contradiction, and for the third eccentric butterfly pneumatic valve. The structure characteristics of the double eccentric pneumatic valve rod eccentric axis position at the same time, make the butterfly plate type sealing face of the cone axis deflection in the cylindrical axis of ontology, that is to say, after the third eccentric, butterfly plate sealing section is no longer true circle, but the ellipse, and so the seal face shape asymmetry, tilt to the center line of the ontology, on the other side is parallel to the centerline of ontology.