Cut-off valve with leakage protection facility

摘要

The invention relates to a valve for the food and drink industry, in the case of which a mixture of product and cleaning liquid, for example, is prevented in the closed condition by means of two valve discs (5, 7). In order, in the event of any water hammer phenomena (hammer-like blows of water in the piping), to prevent the lifting of the valve discs, there is provided a pressure compensation cylinder (16). As the cylindrical outer surface (15) of the latter is alternatively loaded as the valve is switched by the product and the outside air, an additional valve position (Figure 3) is provided to permit cleaning of this outside surface. In this position, a substream (r2) of the cleaning liquid (R) flowing through the lower valve box is diverted in such a way that it emerges in a annular fashion between the pressure compensation cylinder (16) and the angular shoulder (18), is guided onto the outside surface (15) and cleans the latter intensively. <IMAGE>