The certification of a limestone powder for Jenike shear testing

Directorate-General For Translation European Commission

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CRM 116
Industrial research and development

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• Publié par: EUROPEAN-COMMISSION
• Nombre de lectures: 2
• Langue: English
• Poids de l'ouvrage: 3 Mo

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ISSN 1018-5593
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Commission, of the European Communities
Community Bureau of Reference
ber information
REFERENCE MATERIALS
The certification of a limestone powder
for Jenike shear testing
CRM 116 s
Commission of the European Communities
Community Bureau of Reference
REFERENCE MATERIALS
The certification of a limestone powder
for Jenike shear testing
CRM 116
R. J. Akers
Loughborough University of Technology
Loughborough, Leicestershire LE113TU
United Kingdom
Final report
Directorate-General
Science, Research and Development
PARI EÜR0P. Biblioth.
1992 N.C. EUR 14022 EN
CI. Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
L-2920 Luxembourg
LEGAL NOTICE
Neither the Commission of the European Communities nor any person
acting on behalf of the Commission is responsible for the use which might
be made of the following information
DISCLAIMER
Whenever, in this report, a commercial product is identified by the manufac­
turer's name or label, such identification should in no instance be taken
as an endorsement by the Commission or as an indication that the particu­
lar product or equipment is necessarily the best available for the particular
purpose
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1992
ISBN 92-826-3498-1 Catalogue number: CD-NA-14022-EN-C
© ECSC-EEC-EAEC, Brussels • Luxembourg, 1992
Printed in Luxembourg Abstract
In the 1950s Andrew JenDce, using soil mechanics theory as a basis, devised a design procedure which with
modifications and improvements has become a world-wide industry standard for the design for reliable
discharge of silos for powders and bulk solids. As part of this design procedure he devised a method for
characterising the properties of the material to be stored.
After several years of critical study in collaboration with Dr JenDce the Working Party on the Mechanics of
Particulate Solids of the European Federation of Chemical Engineering published a definitive description of the
technique1.
This technique has been used to test a candidate powder for certification by BCR. This report contains a brief
description of the underlying theory, the technique, reasons for the choice of a particular limestone as the
candidate powder, the experimental data and the analysis of that data presented to the Certification Committee.
1 Standard Shear Test Technique Using the Jenike Shear Cell (1989), Institution of Chemical Engineers, Rugby,
England Table of Contents
Page
Abstract III
1 Powder Shear Testing and the Design of Silos 1
2 The Shear Testing of Powders 3
3 Preparation and Characterisation of the Candidate
Powder 17
4 Results of Certification Testing 29
5 Statistical Analysis of Data 45
6 Tables of Certification Data 5
7 Recommendations for Use
Appendix A - Sample Laboratory Data Sheets 71 x B - Derived Data Sheets 7
Appendix C - Standard Shear Test Technique 10x D - Glossary of Terms 143
V-Section 1 • Powder Shear Testing and its use in the Design of Silos
Introduction
Since the 1950's it has been realised that silos for the bulk storage of granular and powdered materials
can be designed so that the stored material may be reelable removed by gravity flow. In this report the
term powder is used to refer to both powders and coarser granular materials. These design procedures
have developed from the work of A.W Jenike. The information about the material to be stored required
for the design procedure is obtained by measurement of its shear flow properties under defined
conditions. A general description of the flow properties of granular substances, their measurement and
use are given in Section 2.
The purpose of this project was to prepare a certified powder that could be used by mose making
these measurements so that they could be sure that their apparatus and technique were giving the
correct results. Many devices have been described for such measurements but for the purpose of this
project it was decided to restrict the investigation to the apparatus and measuring technique of A.W.
Jenike which is widely accepted as an industry standard. The test was devised by Jenike to provide the
necessary data for his method of designing mass-flow silos. Other types of shear apparatus are used
but there is standardisation of their design and insufficient information is available as to how the results
of measurements taken with them compare with those obtained from the Jenike design. The European
Federation of Chemical Engineering has a working party on the Mechanics of Particulate solids which
for some years has been working on the preparation of a standardised testprocedure. This has now
been finalised and published (1989). In carrying out this task the working party has surveyed data
obtained by approximately 20 laboratories using a particular sample of ground limestone. This
procedure was made available to the BCR/89 panel in draft (1982) form.
The reason for the working party publishing a detailed technical procedure is that the original
method of Jenike has never been published in detail except as the operating manual of the shear
apparatus sold by Jenike and Johanson Inc. and it was considered by many concerned that there were
many small details of technique that required attention if reliable results were to be obtained. Many
laboratories have constructed apparatus to the Jenike design, many incorporating improvements to
facilitate measurement, whilst still adhering closely to the design of the shear cell itself. The EFCE
procedure describes the technique in great detail and for consistency uses SI units when describing the
equipment and its use.
Section 3 of the report describes the selection and general properties of the candidate powder,
Section 4 presents the results of the measurements, the statistical analysis of the data is described in 5 and the final Certification Data is presented in Section 6. The Recommendations For Use are
presented as Section 7.
Appendix A comprises samples of laboratory data sheets, Appendix B is the derived data, for all
laboratories, Appendix C the test procedure and Appendix D a Glossary of Terms.