| 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 the 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 underlying 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 the fact that, in relation to the circumferential surface facing the valve stem, the seal is designed as a continual structure with stripping end faces and, on the circumferential surface facing towards the valve housing, in the region of the ends, has recesses which serve, on the one hand, as a clamping surface and, on the other hand, accommodate sealing rings consisting of a softer material than the harder sealing material, these rings being additionally clamped by corresponding surfaces in the valve housing and forming a seal. Use in... Original abstract incomplete. <IMAGE>
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