| 摘要 |
In the beverage industry, use is made of valves which may be classified as double-seat valves and have a plurality of valve stems. Appropriate stripping operations are required during complete opening of the valve heads to ensure that no extraneous matter is swept into the valve space during the opening operations. The valve stems must furthermore be moved from the first to the second displacement position and then reach the actual third position as the open position and displacement devices of correspondingly generous proportions are required. Correspondingly high pressure conditions of the incorporated seals occur in the process. The object is therefore to provide a sealing device by means of which it is possible to meet all the requirements set and to achieve a significant reduction in the size of the displacement device required or its actuating forces. This object is achieved by means of a sealing device, in which the packing is, in relation to the casing surface facing the valve stem, designed as a continuous structure with end surfaces serving as stripping surfaces, and, on the casing surface facing the valve housing, has, in the region of the ends, recesses which, on the one hand, serve as a clamping surface and, on the other hand, accommodate packing rings consisting of a softer material than the harder packing material, these rings being additionally clamped by corresponding surfaces in the valve housing and forming a packing. The sealing device is used in valves, in particular double-seat valves, in the beverage industry. <IMAGE>
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