Process Know-how

Extraction characteristics of bulk materials from silos Part 2: Experimental results

Part 2: Experimental results

Summary: As part of this work experimental investigations were carried out with a rectangular silo. The main focus was on the stress states during emptying by two silo extraction screws and the relationships between the wall normal stresses, the flow profiles and the torques required for the extraction screws. Among other things it was established that the wall normal stresses are lower in moving zones than in stationary zones. The findings and relationships that were discovered can be applied reliably to industrial plants. Part 2 of the article presents the experimental results.

4 Test results
The test results for test series 1 and 4 are given below (Table 1; part 1). A complete evaluation can be found in [18].
4.1 Flow profiles
Knowledge of the flow profiles is very important for explaining and interpreting the stresses that occur in silos. The relationship between the flow profiles and the corresponding stresses is known from mass flow and funnel flow silos [6]. During the trials to determine the flow profiles the test silo described in Part 1 was first filled uniformly up to the specified mark. The sloping surface of the bulk material caused by the central filling...

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