Silo design

The other cause of constmction problems is the introduction of badly chosen, or even unauthorized, changes during constmction in order to expedite the work. Any changes in details, material specifications, or erection procedure must be given careful consideration by both the builder and silo designer. 

J. W. Carson and R. T. Jenkyn, "Load Development and Stmctural Considerations in Silo Design," presented at Eeliable Flow of Particulate Solids II, Oslo, Norway, Aug. 1993. 

P. Marjanovic, Theoretical and practical silo design, Seminar on Storage and Transportation of Bulk Solids, Moreton-in-Marsh, UK, March 1996. 

Conversely, Ehlermann and Schubert (1987) sustained that compressibility results from materials of different composition cannot be compared and that flowability characterization through compressibility must be made specifically for each food variety. Moreover, confined uniaxial compression is a simple compression test that provides an approximate measure of the flowability of powders. Therefore, it is not suitable for silo design but may prove to be a convenient method for process control in any food laboratory (e.g., to evaluate particle cohesion). Table II offers a range value definition for flowability classification by comparing flow function (ratio between the maximum consolidation stress and unconfined yield stress) with compressibility. 

Van der Kooi, P. J. (1997) Silo design, well begun is half done. Powder Handling and Processing, 9 (4), October/December issue, 326-328. 

Core flow. This occurs when the powder flows towards the outlet of a silo in a channel formed within the powder itself [Figure 10.1(a) . We will not concern ourselves with core flow silo design. Figure 10.3 (a-d) shows sketches taken from a sequence of photographs of a hopper operating in core flow. Note the regions of... 

Vandellos I has three silos designed to store the grai ite sleeves (reactor fuel siq>port). In the silo number 1 some otiier radwastes were stored, as low level solid radwastes and two fuel elements. An intematioDal request for tenders was made in order to undertake the extraction and conditioning all these radwastes. The project was awarded to the Spanish/French Consortium EQUIPOS NUCLEARES-FRAMATOME. 

Brown, G. and J. Neilsen. 1990. Silos. London Spon. Silo design and construction from a U.K. perspective. 

Reimbert, M. L. and A. M. Reimbert. 1987. Silos, 2nd ed. Paris Lavoiser. The Reimberts have developed one of the most commonly used methods of silo design. 

Safarian, S. S. and E. C. Harris. 1985. Design and Construction of Silos and Bunkers. New York Van Nostrand Reinhold. U.S.-based silo design. 

Rotter, M.J. (2005) Silo design loads from stored bulk solids the provisions of the new Eurocode EN 1991-4 (2005). Proceedings of the IMechE Seminar on Specifying and Designing Safe Storage Silos, IMechE. 

Since the state was to pass from filling (close to an active stress state) to passive, the pressure just below an abrupt step is easily determined as the Janssen value multiplied by the ratio of passive to filling values of lateral pressure ratio K /Ki). The ratio of peak symmetrical discharge pressure to symmetrical filling pressure is a very widely used variable, and its origins can be seen here to have some foundation in mechanics. This ratio is so important in silo design that it is given a symbol and defined as... 

The topics covered by thebook will include the characterisation of individual particles and bulk particulate materials, silo design for strength and flow, pneumatic conveying systems, mechanical conveying, small-scale operations. Belt conveying will not be covered in this volume. 

Biaxial testers measure shear stresses related to normal stresses. However, the flow-function graph and its interpretation for silo design requires the calculation of principal stresses (fc and aO from the normal and shear stress data by the use of yield loci and Mohr s circles (a mathematical tool). In concept, a perfect imiaxial tester can directly apply and measure principal stresses, making the construction of yield loci and use of Mohr circles unnecessary. This would expedite the completion of flow functions and reduce testing time. 

Many users of flowability data, especially for quality control purposes, do not have the skills, patience, or need to interpret the graphical results of shear cell testing. These graphs show unconfined yield strength, bulk density, wall friction, and internal friction angles as functions of major principal stress. While this data is vital for a silo designer, most quality control users would prefer a single number that would tell them in quantitative units how one sample compares to another or to a reference value. 

Very often the testing of bulk solids is not done with respect to silo design. Typical other questions are ... 

Schwedes, J. Influence of Wall Friction on Silo Design in Process and Structural Engineering, Ger.Chem.Engng. 8(1985), 131/138... 

Taking into consideration all the different properties of cohesive to very cohesive powders tested (particle size distribution, moisture content, material properties etc.), the model fit can be characterised as satisfactory to good. Thus, the model has proved its effectiveness and can be accordingly applied in reliable silo design for flow and pressure calculation [26]. 

With the mechanistic approach in the background, there are two objectives in this paper. One is to present a method by which component stress data for Jenike loci (t, ctn), can be analysed to retrieve mechanistic failure property coefficients, assuming a statistically significant number of data. These coefficients may then be used in three ways to characterise the bulk solid, to numerically determine the data required for silo design or, to convert Jenike loci into principal stress loci presented in principal stress space. 

J. Schwedes, D. Schulze, Examples of Modem Silo Design, Bulk Solids Handling 11... 

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