| 摘要 |
In a system, the untreated raw sludge is conveyed from a tank (1) with a level controller (2) via a centrifugal pump (3), two slide valves (4, 5) and a heat exchanger (6) into a pasteurisation tank (7) with two level switches (8, 9). After the tank (7) has been filled the slide valve (4) is closed. The centrifugal pump (10) then circulates the sludge until the pasteurisation temperature is established by a thermostat (11). Circulation is continued for 30 minutes while maintaining the temperature. The heating medium is hot water. A second analogous circuit which can be connected to the pump (3) leads via slide valves (24, 25) into a heat exchanger (26) and into a pasteurisation tank (27). While the sludge is being pasteurised in the first circuit, the second circuit is emptied and then filled. The tank (27) is provided with two level controllers (28, 29). After completion of the filling process, the pump (30) is switched on to circulate, the slide valve (24) is closed and the pump (3) is switched off. The thermostat (31) establishes that the pasteurisation temperature has been reached and sets the start of the 30-minute maintenance time. The disinfection takes place free, with little cost for apparatus, saving energy. Disinfection is ensured. No operation takes place under pressure and there is no increase in the water content of the sludge. The danger of recontamination is very substantially eliminated. <IMAGE>
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