| 摘要 |
A method and apparatus for automatically measuring the grain fineness, the gypsum content and the limestone content of a cement sample. A first fraction of the sample is loaded by a vibrating hopper into a crucible resting on an automatic scale. This crucible is handled sequentially by tongs on two revolving arms carried on slidable vertical shafts. The circular paths of the arms intersect at a point just above the scale. Motions of the arms and of the tongs are controlled by a programming unit. The weighed sample is poured into a sieve and the weight of oversize grains is automatically related to the sample weight. Gypsum is measured by heating a second fraction of the sample at 1000 DEG C. plus in an oxygen stream, Fe powder being added from a fixed hopper. The crucible is raised into an induction furnace. Released SO2 is bubbled in a titration cell to which potassium iodate is gradually added by a burette giving an automatic read-out of the SO3 (gypsum) titration. Limestone is also measured by heating a third fraction of the sample to release CO2, and measuring the weight increase of a column, filled with NaOH which absorbs the released CO2, which is placed on a second automatic scale. The column is automatically disconnected from the gas circuit before being weighed.
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