Double eccentric sealing butterfly valve introduction, pictures, sales
The double eccentric sealing butterfly valve is further improved on the basis of the single eccentric butterfly valve. Its structural feature is that the shaft center of the valve stem deviates from the center of the disc and the center of the body. The sealing structure is shown in the figure below.
The center of rotation of the double eccentric sealing butterfly valve disc (ie, the center of the valve shaft) forms a dimension a offset from the disc sealing section and a dimension b offset from the centerline of the valve body.
On the basis of the single eccentric sealing butterfly valve, the center of rotation of the valve plate (that is, the center of the valve shaft) is offset by a dimension b with the center line of the valve body. As a result of the offset, when the double eccentric sealing butterfly valve is fully open, The valve plate sealing surface will be completely separated from the valve seat sealing surface, and a gap y larger than that in the single eccentric sealing butterfly valve is formed between the valve plate sealing and the valve seat sealing surface.
Due to the appearance of the dimension b offset, the turning radius of the valve plate is also divided into long-radius rotation and short-radius rotation. On the large semicircle of the valve plate with long-radius rotation, the tangent of the rotation trajectory of the sealing surface of the valve plate will seal with the valve seat The surface forms a p angle, so that when the valve plate is opened and closed, the sealing surface of the valve plate has the effect of gradually exiting and gradually entering the sealing surface of the valve seat relative to the sealing surface of the valve seat, thereby further reducing the gap between the two sealing surfaces of the butterfly valve sealing pair when the valve plate is opened and closed. mechanical wear and abrasions.
When this type of butterfly valve is opened, the butterfly plate is immediately separated from the valve seat, which greatly reduces the unnecessary excessive extrusion and scraping between the butterfly plate and the valve seat, reduces the opening resistance, reduces wear, and improves the life of the valve seat.
Double eccentric butterfly valve can use metal seat, which can be used in high temperature field. Because the sealing principle belongs to the position sealing structure, that is, the sealing surface between the disc and the valve seat is a line contact seal, and the elastic deformation caused by the disc pressing the valve seat produces a sealing effect, so the closed position is required to be high, and the pressure bearing capacity is relatively high. This is the main reason why people think that butterfly valve products are not resistant to high pressure and have a large surge.
Double eccentric butterfly valve is mainly used as a shut-off and adjustment equipment on water pipes.
When buying a double eccentric butterfly valve, it is very important to choose a good manufacturer. It not only saves costs, but also has high cost performance, reliable quality and perfect after-sales service. VALTECCN valve has been engaged in the manufacture of butterfly valves for many years. You may wish to consult and understand VALTECCN before making a decision.