| 摘要 |
A vertical pulp treatment vessel having a top and bottom, such as a continuous or batch digester, has at least a first substantially annular screen assembly disposed within the vessel between the top and bottom. A first substantially annular header is associated with the first screen assembly and first and second withdrawal conduits extend outwardly from the header and are in fluid communication with it. A barrier, such as a radially extending plate, is disposed in the header between the withdrawal conduits, the withdrawal conduits being adjacent each other (typically spaced from each other between about 2-30 DEG , e.g. between about 10-20 DEG ). A small, compared to the prior art, platform is provided for allowing access to the withdrawal conduits, and automatically controlled valves or like structures in or associated with the conduits, the platform having an arcuate extent of less than 180 DEG , typically less than about 110 DEG (e.g. about 90 DEG or less). Typically, a second annular screen assembly, like the first screen assembly, with third and fourth withdrawal conduits circumferentially spaced from each other between about 2-30 DEG , and have a centerline that is circumferentially spaced from the first and second withdrawal conduit centerline less than about 110 DEG (e.g. about 80-110 DEG , typically about 90 DEG ), so that on the single platform the four withdrawal conduits, and the automatically operated valves associated therewith, may be accessed. |
