| 摘要 |
The invention relates to a butterfly valve comprising a valve housing 1 with a passage for fluid medium, a valve seat 10 formed by a ring 7 arranged so as to be capable of being displaced in the radial direction in a groove 8 in the valve housing and also to be capable of being elastically deformed in its shape in the radial direction in the groove, a valve member 3 with a sealing surface 6 on its periphery, the valve member having an oval shape in all sections which intersect said sealing surface in planes parallel to the side of the valve member with the long axis of the ovals at right angles to the axis of rotation of the valve member, which valve member is arranged so as to be capable of being rotated about an axis of rotation 4 by means of a spindle 5 between an open position and a closed position, in which the sealing surface 6 on the periphery of the valve member is pressed against the seat ring, and also means 2, 13, 15 arranged so as, when the valve member is rotated from the closed position to the open position, retain the seat ring in its position in the groove and also essentially maintain the shape adapted to the sealing surface on the valve member, which the seat ring has obtained. At least that part of the seat ring 7 which forms the seat 10 itself consists of a plastic ring. A resilient metal ring 13 separate from or integral with the seat ring is also arranged in said groove so as to increase the resistance of the seat ring to radial deformations and so as to prevent its circumference being lengthened when the seat ring is subjected to radial stresses. Finally, the seat has two seat surfaces 11, 12, the shape of which is adapted to and corresponds to the shape of the sealing surface 6a, 6b of the valve member facing the seat in the closed position of the valve member in a plane of intersection at right angles to the axis of rotation and coincident with said long axis. <IMAGE> |
