| 摘要 |
The invention concerns a method and a tubular diffuser for use in the wood pulp and cellulose process, which tubular diffuser has been connected to a transfer pipe for the pulp or directly as an extension to the storage and reactor tanks. The arrangement can be used as a diffuser and means of precipitation along with a chemical mixer. The tubular diffuser according to the invention consists of a tubular shell, inside which has been mounted a filter arrangement for separating a precipitated filtrate from the fibre pulp and a separating apparatus for feeding of the washing liquid. The feeding and discharge pipes of the tubular diffuser have been provided with valves or shutoff elements. In the pulp transport direction upstream from the discharge pipe of the arrangement there is a fluidising apparatus or a fluidising pulp pump. The washing and precipitation functions of the tubular diffuser are periodic. For the washing, the pulp suspension is halted between the shutoff elements, in which case the flow of the washing liquid through the pulp suspension is technically easier to control and it has a constrained transport route. In the precipitation function, the shutoff element of the arrangement is kept throttled or closed during the feeding of the pulp suspension, and the pressure of the incoming suspension filters the liquid in the suspension through the filter arrangement. The washing and precipitation functions if necessary can be combined in the same period. At the end of the period, the pulp which is in the form of a plug inside the diffuser is displaced by feeding a new pulp suspension. The periodic activity of the arrangement is compensated by parallel-connecting of arrangements in relation to the main pulp flow, so that the overall pulp flow remains continuous, either depending on the direct connection or by using equalisation tanks. The desired total washing effect is achieved by coupling arrangements in series. When the arrangement is used as a chemical mixer in the bleaching process, the desired chemicals whose mixing is done in the fluidiser of the outlet arrangement are fed in instead of the washing water. <IMAGE>
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