Sealing principles(graphic)
Single eccentric sealing butterfly valve sealing principles
double eccentric sealing butterfly valve sealing principles
As on the basis of single eccentric butterfly valve to form dimension b bias of butterfly plate rotation center (both valves axis center) and the body centerline, making butterfly valve in its opening process, the disc sealing surface is faster sperated from seat sealing surface compared with single eccentric butterfly valve, when disc rotates to 8 °~ 12 °, the butterfly plate sealing surface is completely out of the valve seat sealing, when fully opened, it forms a larger gap y between the two sealing surface, this type butterfly valve design, significantly reduces mechanical wear between the two sealing surface and crowding pressure deformation, so make the sealing performance improve even more.
As the disc rotating center (ie, valve shaft center) and disc sealing section according to a bias setting, makes the valve in opening process, the disc sealing surface gradually away from the valve seat sealing surface, disc rotates to 20 °~ 25 °, the disc sealing surface is completely out of the valve seat sealing surface, when fully opened, the two sealing surface forms gap x, and thus makes the butterfly valve in the hoist process, relatively mechanical wear and extrusion between two sealing surface substantially reduces, thus ensuring the sealing butterfly valve.
three eccentric sealing butterfly valve sealing principles
As on the basis of double eccentric butterfly valve make the seat centerline and body centerline further forming aβangle bias, making the butterfly valve in its opening process, the disc sealing surface immediately away from the valve seat sealing surface in the opening moments, while in the closing moments will contact and compress the valve seat sealing surface. When fully opened, between the two sealing surface forms a same gap y with double eccentric sealing butterfly valve, this butterfly valve design, completely eliminating the mechanical wear and abrasion between two sealing surface, making the sealing performance and service life of butterfly valve greatly enhanced.
variable eccentric sealing butterfly valve sealing principles
Variable eccentric butterfly valve is unique in installation of disc stem axis is a three-axis structure, the two-axis segment of three sections axis stem is concentric, while the center section shaft centerline deviates a center distance at both ends, disc is installed on the middle shaft segment. This eccentric structure makes the disc become double eccentric shape in full open position, while disc rotates to the closed position, it has become a single eccentric shape. Due to the eccentric shaft effect, when nearly closed, disc moves a distance into the seat sealing cone surface, disc is consistent to the seat sealing surface, to achieve a reliable sealing performance.
