| 摘要 |
A description is given of a valve, whose generation of sealing force is independent of the closing movement of the valve disc 2. This is achieved by virtue of the fact that a sealing element 6 is only acted upon by internal pressure once the valve disc 2 has reached its closed position in the core 14. This internal pressure is proportional, in each operating state, to the differential pressure above the valve disc, resulting in a seal which can only be abraded mechanically between the expanded seat ring 6 and the housing 1 by means of solids found in the operating medium. For higher operating temperatures, a modified design is proposed which exclusively uses metallic components. Due to the completely symmetrical design of the valve disc 2 and its central mount, it is possible to operate the valve disc 2 by means of a pneumatic or hydraulic cylinder and, by using different pressure levels within or outside the fitting, to operate it solely by the operating medium itself. Only a minimum operating torque is required for this due to a special arrangement of the sealing elements. <IMAGE>
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