SIST ISO 15117-1:2005
(Main)Coal flow properties -- Part 1: Bin flow
Coal flow properties -- Part 1: Bin flow
ISO 15117-1:2003 sets out methods for the measurement of the flow properties of coal, primarily for the design of bins and chutes. It also provides some guidance on the presentation of these data for analysis and design.
ISO 15117-1:2003 consists of a bulk density test and a yield locus test giving information on material flow properties. It also describes a further test, called the wall yield locus, which measures the friction between coal and bin wall material.
Although ISO 15117-1:2003 is nominally for coal, the principles and apparatus may be used for coke and other semi-cohesive particulate materials where a knowledge of flow properties is required.
Propriétés d'écoulement du charbon -- Partie 1: Écoulement d'une trémie
Lastnosti toka premoga – 1. del: Dotok v zabojnik
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 15117-1
First edition
2004-05-01
Coal flow properties —
Part 1:
Bin flow
Propriétés d'écoulement du charbon —
Partie 1: Écoulement d'une trémie
Reference number
ISO 15117-1:2004(E)
©
ISO 2004
---------------------- Page: 1 ----------------------
ISO 15117-1:2004(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
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Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 15117-1:2004(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Notation. 4
5 Sampling and sample preparation . 5
5.1 Sampling. 5
5.2 Sample preparation. 5
5.2.1 General. 5
5.2.2 Sample top size . 6
5.2.3 Sample division. 6
5.2.4 Moisture content. 6
6 Determination of yield locus. 6
6.1 Apparatus. 6
6.2 Instantaneous yield locus. 6
6.2.1 General. 6
6.2.2 Preconsolidation of the sample. 7
6.2.3 Shear consolidation. 8
6.2.4 Shearing of the sample. 9
6.2.5 Determination of the complete family of instantaneous yield loci . 10
6.3 Other yield loci. 10
6.3.1 High-pressure yield locus. 10
6.3.2 Time yield locus . 10
6.3.3 Temperature yield locus. 12
6.3.4 Vibration yield locus. 12
6.4 Reporting and presentation of results. 12
6.4.1 General. 12
6.4.2 Prorating procedure. 13
6.4.3 Determination of the instantaneous flow function .13
6.5 Acceptance of results and precision of the determination . 14
7 Determination of wall yield locus . 15
7.1 Principle. 15
7.2 Apparatus. 15
7.3 Sample. 15
7.4 Procedure. 15
7.5 Calculations. 16
7.6 Determination of wall friction angle (φ). 17
7.7 Precision of determination. 17
8 Determination of bulk density/compressibility. 18
8.1 General. 18
8.2 Apparatus. 18
8.3 Sample. 18
8.4 Procedure. 18
8.5 Calculations. 19
8.6 Presentation of results . 19
8.7 Precision of determination. 19
Annex A (informative) Bin design philosophy. 23
© ISO 2004 – All rights reserved iii
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ISO 15117-1:2004(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15117-1 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 1,
Coal preparation: Terminology and performance.
ISO 15117 consists of the following parts, under the general title Coal flow properties:
Part 1: Bin flow
Part 2: Rapid assessment
iv © ISO 2004 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 15117-1:2004(E)
Coal flow properties —
Part 1:
Bin flow
1 Scope
This part of ISO 15117 sets out methods for the measurement of the flow properties of coal, primarily for the
design of bins and chutes. It also provides some guidance on the presentation of these data for analysis and
design.
This part of ISO 15117 consists of a bulk density test and a yield locus test giving information on material flow
properties. It also describes a further test, called the wall yield locus, which measures the friction between coal
and bin wall material.
Although this part of ISO 15117 is nominally for coal, the principles and apparatus may be used for coke and
other semi-cohesive particulate materials where a knowledge of flow properties is required.
NOTE Some discussion of the relevance of coal flow properties to bin design philosophy is provided in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1213-2:1992, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and
analysis
ISO 1953:1994, Hard coal — Size analysis by sieving
ISO 589:1981, Hard coal — Determination of total moisture
ISO 13909-2: 2002, Hard coal and coke — Mechanical sampling — Part 2: Coal — Sampling from moving
streams
ISO 13909-4: 2001, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test
samples
ASTM D 6128-00, Standard Test Method for Shear Testing of Bulk Solids Using the Jenike Shear Cell
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 1213-2 and those below apply.
NOTE In this part of ISO 15117, the terms pressure and stress are used synonymously because this convention is
used in research and literature on this subject. Some other terms have not yet been standardized in the literature. These
are listed below, together with a reference to the preferred nomenclature.
3.1
axi-symmetric flow
SEE mass flow
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ISO 15117-1:2004(E)
3.2
bulk density
the mass of a sample of particulate solid including moisture, divided by its total volume
NOTE The level of consolidation stress is critical to any measurement of bulk density.
3.3
bulk material
semi-cohesive particulate material such as coal and other minerals
3.4
cohesion
the shear stress at yield under zero normal stress
NOTE This parameter is not normally quantified.
3.5
compaction
the process of permanent volume reduction of a bulk material by application of a consolidating stress
3.6
consolidation
SEE compaction
3.7
core flow
SEE funnel flow
3.8
critical consolidation, in a shear cell
the state existing in a bulk sample within a shear cell when the cell stem travel becomes independent of
applied shear force
NOTE Under these conditions, the bulk material is deforming without change in voidage. The material is said to be in
its critical state.
3.9
critical state
SEE critical consolidation
3.10
critical pipe or rathole diameter
the diameter of a rathole or pipe at which the rathole or pipe becomes unstable
NOTE The critical rathole diameter varies with consolidation pressures.
3.11
effective angle of internal friction
δ
the angle with the horizontal axis of a line through the origin and tangent to the Mohr circle through the end
point of the yield locus
See Figure 4.
NOTE The line through the origin is called the effective yield locus.
3.12
expanded flow
flow from a bin which has two distinct cross-section regimes
NOTE Funnel flow exists in the lower cylindrical section of the bin whereas mass flow exists in the conical outlet
hopper or hoppers.
2 © ISO 2004 – All rights reserved
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ISO 15117-1:2004(E)
3.13
flow function, instantaneous
FF
for a given bulk material, a plot of the unconfined yield strength σ versus the major consolidating pressure,
c
values being obtained from the yield loci
NOTE This is a measure of the bulk strength or flowability of a bulk material, in a de-aerated state, when first loaded
into a bin or consolidated in a shear cell.
3.14
flow function, time storage
for a given bulk material, a measure of the increase in unconfined yield strength of material subjected to
standard consolidation conditions for a defined time, typically 24 h to 48 h
3.15
funnel flow
the flow that occurs during gravity storage when bulk material sloughs off the surface of the material and
discharges through a vertical channel which forms within the material in the bin whenever material is drawn
from the outlet
NOTE Material adjacent to the bin walls remains stationary.
3.16
hopper half-angle
α
the angle between one wall of the hopper and the vertical
3.17
major consolidating pressure
major consolidating stress
σ
1
the pressure given by the Mohr circle passing through the end point of the instantaneous yield locus and the
tangent to the locus
See Figure 4.
3.18
mass flow
the flow that occurs when bulk material is in motion at every point in a bin whenever material is drawn from the
outlet
NOTE Mass flow is normally symmetric and is usually axi-symmetric in three dimensions in a conical hopper, or
plane in two dimensions in a wedge hopper.
3.19
natural fines
the fraction of the sample screened below 4 mm or 6 mm
3.20
particulate solid
an assembly of solid particles having properties independent of the number of particles present
SEE bulk material (3.3).
3.21
plane flow
SEE mass flow
© ISO 2004 – All rights reserved 3
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ISO 15117-1:2004(E)
3.22
shear apparatus
equipment for subjecting the material under test to shear deformation under conditions of controlled normal
pressure
3.23
unconfined yield strength
σ
c
the major principal stress that must be applied tangentially to an unconfined surface to cause yielding
3.24
voidage or voids ratio
the volume of the voids within a quantity of bulk material, divided by total volume (voids plus solids)
3.25
yield locus, effective
see effective angle of internal friction
3.26
yield locus, instantaneous
the shear force versus normal force curve for plastic failure of an over-consolidated bulk material of given
initial voidage; this defines conditions when material flow commences
3.27
yield locus, time
the shear force versus normal force curve for plastic failure of a bulk material after being held at rest under a
standard pressure for a given time
3.28
yield locus, wall
φ
the locus of shear force versus applied normal force on a sample of bulk material moving in contact with a
boundary surface or wall
NOTE This is the angle determined by the shear and normal force shown in Figure 10.
4 Notation
The following quantity symbols are used in this part of ISO 15117:
F Unconfined yield force under instantaneous conditions
h Compacted height, in bulk density test
S Steady-state shear force during the “shear consolidation” phase of the shear test
S Steady shear force obtained in the wall friction test
f
S An uncorrected value of S determined from the shear test
t
S The value of S selected for a particular level of consolidation, and used for prorating (S ) values
s i t
S Maximum value of shear force obtained during the “sample shear” phase of the shear test
i
()S An uncorrected value of S determined from the shear test
it
()S A corrected value of S obtained using Equation (1)
ip
4 © ISO 2004 – All rights reserved
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ISO 15117-1:2004(E)
V Vertical force due to total vertical load applied at the shear plane during the “shear consolidation” phase
of shear test X
V = V + V
a b
V Vertical force due to the weight of the shear lid, shear ring and bulk solid above the shear plane, i.e.
a
contained within the shear ring
V Vertical force due to the weight applied to the shear lid during the “shear consolidation” phase of the
b
shear test
Vertical force due to the weight applied to the shear lid during the “sample shear” phase of the shear
V
bi
test
V Vertical force applied in the wall friction test
f
Vertical force due to total vertical load applied at the shear plane during “sample shear” phase of the
V
i
shear test
= V +
V V
i a bi
V Vertical force due to the weight applied to the twisting lid during the “preconsolidation” phase of the
t
shear test
V Major consolidating force on sample
1
W Weights used in the wall friction test
f
W Mass of the weight hanger or carrier
h
σ Unconfined yield strength (or stress) of a bulk solid
c
σ Major consolidation pressure (or stress) of a bulk solid
1
φ Wall friction angle
5 Sampling and sample preparation
5.1 Sampling
The sample for flow property analysis shall be taken in accordance with ISO 13909-2. Care should be taken at
all stages of sampling, sample handling and testing to prevent undue breakage.
Where test results are to be used for design of bins and transfer points, the material sampled should be
related to the “problem” i.e., in the state that creates the most difficult flow conditions. For example, where the
material breaks down with time and moisture, a weathered sample should be used.
5.2 Sample preparation
5.2.1 General
Flow property measurements are carried out on the natural fines fraction of the sample. The top size of the
fraction used shall be recorded.
© ISO 2004 – All rights reserved 5
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ISO 15117-1:2004(E)
The sample for testing shall be prepared by the methods given in ISO 13909-4. Sufficient sample shall be
taken to yield at least 1 kg of the natural fines. If, however, time-delayed tests are to be carried out also,
sufficient sample to yield 5 kg of minus 4 mm material is required.
5.2.2 Sample top size
After drying, the sample shall be sieved according to the method set out in ISO 1953 to separate the natural
fines. All tests shall be carried out on the minus 4 mm material occurring naturally in the sample.
5.2.3 Sample division
Where necessary, the sample shall be divided by riffling or mechanical sample division to provide the required
quantity for analysis. Dust loss and size degradation shall be minimized.
5.2.4 Moisture content
In consideration of specific problems, the sample may need to be dry or at a predetermined moisture content.
The screened sample shall be at the required moisture content. The moisture contents of the initial sample
and screened sample shall be measured before and after flow property testing, in accordance with ISO 589,
and should not differ by more than 0,5 % on a mass basis. Samples should be stored in sealed containers to
maintain moisture content. The moisture content of the natural fines in relation to the bulk sample shall be
determined.
6 Determination of yield locus
6.1 Apparatus
A Jenike-type, direct shear tester having provision for the continuous display of shear/deformation using a
chart recorder is required. Standard shear cells (see Figure 1) have internal diameters of 95 mm or 63,5 mm.
The lower ring is fixed to the frame and the upper ring is free to move under the action of the applied force.
Ring movement is resisted by the material under test in the shear cell. To carry out the test, a twisting lid,
shear lid, mould ring, twisting wrench, weight carrier, weights, spoon, scraper and brush are required. The
standard deformation rate is (2,5 ±0,2) mm/min.
Where preconsolidation pressures are above 50 kPa, a cell of 63 mm nominal inside diameter cell is preferred.
The shear cell of smaller diameter permits the higher pressures to be generated with smaller, more
manageable normal loads. The cell diameter used should be a part of any statement of results.
NOTE Strict comparison is possible only on results from cells of the same dimensions.
6.2 Instantaneous yield locus
6.2.1 General
The instantaneous yield locus is determined using the 95 mm low pressure cell (see 6.1). The shear cell shall
be filled with a fresh sample for each test.
To ensure that the cell material is critically consolidated when measurements are made, the limited travel in
the Jenike cell necessitates an iterative trial-and-error consolidation procedure. Critical consolidation is the
point where cell stem travel is first independent of shear force as shown in Figure 3, curve B.
The trial-and-error procedure shall approach critical consolidation from below rather than above, as the latter
can lead to erroneous results (see Figure 3, curve C, point X).
6 © ISO 2004 – All rights reserved
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ISO 15117-1:2004(E)
6.2.2 Preconsolidation of the sample
Place the cell base, shear ring and mould ring on the shear tester (see Figure 1). Adjust the offset of the shear
ring to approximately 3 mm.
Place a sample of the material to be tested in the shear cell, layer by layer, each layer being spread lightly and
uniformly with a spoon, taking care not to leave impressions which could lead to preferential shear planes.
Scrape off excess material flush with the top of the mould ring. Cover the material with the twisting lid.
Apply a vertical force, V , to the twisting lid by means of a weight carrier, and, by using the special twisting
t
wrench, apply a number of oscillating twists (amplitude approximately ± 20°) to the lid. During this procedure,
care should be taken not to press down on the twisting lid and not to impede the motion of the shear ring, as it
tends to follow the motion of the twisting lid.
Select the value of V and the number of twists to be applied by trial and error. For most dry samples, V is
t
t
made equal to V, the normal force used in the consolidation-under-shear procedure described below.
However, for high moisture samples, values of V equal to 2 to 4 times V may be required. The number of
t
complete twists applied initially is about 20.
Remove the weight carrier from the twisting lid.
Lift off the mould ring while holding down the twisting lid and shear ring.
Slide the twisting lid off and scrape off the excess material flush with the top of the shear ring. In these
operations, care should be taken to avoid any movement of the shear ring. Clean away excess material with
the brush.
Key
1 twisting lid
2 mould ring
3 shear ring
4 base
5 frame
a
Offset.
Figure 1 — Jenike shear cell — Set-up for preconsolidation
© ISO 2004 – All rights reserved 7
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ISO 15117-1:2004(E)
6.2.3 Shear consolidation
Consolidation of the sample is completed by a shearing operation, which causes the material to flow under the
consolidating stresses until a steady-state shear value is reached, or closely approached.
Place the shear lid on the sample, taking care to centre it within the shear ring, and ensure that the drive
bracket is aligned with the transducer stem. Apply the force, V , to the lid using an appropriate weight, and
b
advance the stem of the direct shear tester against the bracket (see Figure 2).
Allow shearing to proceed until a condition is reached where a layer of the material across the whole sample
is caused to flow plastically, and the recorded shear force reaches a steady value, S. Ideally, this steady value
of shear force should be reached when the shear ring is concentric with the base of the cell.
Reverse the stem travel until the shear force drops to zero. Then remove the force, V .
b
It is important that the steady-state shear force, S, is reached as indicated by curve B, Figure 3; the sample is
then critically consolidated. If the shear force continues to rise for the complete stem travel (curve A, Figure 3),
the sample was under-consolidated during the preconsolidation phase. Generally, this means that an increase
is needed in the preconsolidation force, V, or the number of twists used. If the shear force reaches a
t
maximum then reduces (curve C, Figure 3), the sample was over-consolidated during the preconsolidation
phase. Generally, this means that either the value of V or the number of twists was excessive. If either of
t
these conditions occurs, the test should be repeated.
Key 5 frame
1 shear lid 6 bracket
2 shear ring 7 loading stem
3 shear plane 8 pin
a
4 base Offset.
Figure 2 — Jenike shear cell — Set-up for shear consolidation
8 © ISO 2004 – All rights reserved
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ISO 15117-1:2004(E)
Key
A under-consolidated
B critically consolidated
C over-consolidated
X Stem travel
Y Shear force, S (N)
a
Limit of travel.
Figure 3 — Types of shear consolidation curve
6.2.4 Shearing of the sample
The third stage of the test is the actual shearing of the sample under force , smaller than V. The procedure
V
i
shall be as given below.
Apply force ( ) to the shear lid.
V
bi
Advance the stem of the machine until it almost touches the bracket.
Let shearing proceed until the recorder pen reaches and passes a maximum value, S .
i
Retract stem and remove force, .
V
bi
Remove the entire cell including the shear lid and split the shear ring and base apart. Striking the lid or bottom
of the cell, check to see that the shear plane is between the ring and the base and not angled up or down. If
the shear plane is not correct, the complete test shall be repeated.
Once for each level of consolidation, determine the additional vertical force (V ) above the shear plane.
a
NOTE V is the vertical force due to
a
a) shear lid,
b) shear ring, and
c) mass of material contained within the ring.
© ISO 2004 – All rights reserved 9
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ISO 15117-1:2004(E)
6.2.5 Determination of the complete family of instantaneous yield loci
Repeat the entire three-stage procedure two more times for the same level of consolidation, applying the force,
V , to the shear lid during shear consolidation by applying forces and to the lid during shear. A
V V
b
b2 b3
sample of fresh material is used for each test. This set of results will be used to provide one complete yield
locus.
Perform a complete series of tests at two other levels of consolidation, one higher and one lower than the first
level. Thus, the minimum number of valid tests which are performed to obtain the family of instantaneous yield
loci is nine.
NOTE In order to clarify the procedure and to illustrate with numerical values, an example is set out in 6.4.3, using a
coal at 10 % total moisture content. This example gives an idea of the forces needed to be applied to the shear lid for the
nine tests required. In the selection of vertical forces, care should be taken that all results lie in the valid range, as
indicated in Figure 4. The numerical values used later are set out in Table 1.
Table 1 — Yield locu
...
SLOVENSKI STANDARD
SIST ISO 15117-1:2005
01-november-2005
Lastnosti toka premoga – 1. del: Dotok v zabojnik
Coal flow properties -- Part 1: Bin flow
Propriétés d'écoulement du charbon -- Partie 1: Écoulement d'une trémie
Ta slovenski standard je istoveten z: ISO 15117-1:2004
ICS:
73.040 Premogi Coals
SIST ISO 15117-1:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 15117-1:2005
---------------------- Page: 2 ----------------------
SIST ISO 15117-1:2005
INTERNATIONAL ISO
STANDARD 15117-1
First edition
2004-05-01
Coal flow properties —
Part 1:
Bin flow
Propriétés d'écoulement du charbon —
Partie 1: Écoulement d'une trémie
Reference number
ISO 15117-1:2004(E)
©
ISO 2004
---------------------- Page: 3 ----------------------
SIST ISO 15117-1:2005
ISO 15117-1:2004(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 15117-1:2005
ISO 15117-1:2004(E)
Contents Page
Foreword. iv
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Notation. 4
5 Sampling and sample preparation . 5
5.1 Sampling. 5
5.2 Sample preparation. 5
5.2.1 General. 5
5.2.2 Sample top size . 6
5.2.3 Sample division. 6
5.2.4 Moisture content. 6
6 Determination of yield locus. 6
6.1 Apparatus. 6
6.2 Instantaneous yield locus. 6
6.2.1 General. 6
6.2.2 Preconsolidation of the sample. 7
6.2.3 Shear consolidation. 8
6.2.4 Shearing of the sample. 9
6.2.5 Determination of the complete family of instantaneous yield loci . 10
6.3 Other yield loci. 10
6.3.1 High-pressure yield locus. 10
6.3.2 Time yield locus . 10
6.3.3 Temperature yield locus. 12
6.3.4 Vibration yield locus. 12
6.4 Reporting and presentation of results. 12
6.4.1 General. 12
6.4.2 Prorating procedure. 13
6.4.3 Determination of the instantaneous flow function .13
6.5 Acceptance of results and precision of the determination . 14
7 Determination of wall yield locus . 15
7.1 Principle. 15
7.2 Apparatus. 15
7.3 Sample. 15
7.4 Procedure. 15
7.5 Calculations. 16
7.6 Determination of wall friction angle (φ). 17
7.7 Precision of determination. 17
8 Determination of bulk density/compressibility. 18
8.1 General. 18
8.2 Apparatus. 18
8.3 Sample. 18
8.4 Procedure. 18
8.5 Calculations. 19
8.6 Presentation of results . 19
8.7 Precision of determination. 19
Annex A (informative) Bin design philosophy. 23
© ISO 2004 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 15117-1:2005
ISO 15117-1:2004(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15117-1 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 1,
Coal preparation: Terminology and performance.
ISO 15117 consists of the following parts, under the general title Coal flow properties:
Part 1: Bin flow
Part 2: Rapid assessment
iv © ISO 2004 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 15117-1:2005
INTERNATIONAL STANDARD ISO 15117-1:2004(E)
Coal flow properties —
Part 1:
Bin flow
1 Scope
This part of ISO 15117 sets out methods for the measurement of the flow properties of coal, primarily for the
design of bins and chutes. It also provides some guidance on the presentation of these data for analysis and
design.
This part of ISO 15117 consists of a bulk density test and a yield locus test giving information on material flow
properties. It also describes a further test, called the wall yield locus, which measures the friction between coal
and bin wall material.
Although this part of ISO 15117 is nominally for coal, the principles and apparatus may be used for coke and
other semi-cohesive particulate materials where a knowledge of flow properties is required.
NOTE Some discussion of the relevance of coal flow properties to bin design philosophy is provided in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1213-2:1992, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and
analysis
ISO 1953:1994, Hard coal — Size analysis by sieving
ISO 589:1981, Hard coal — Determination of total moisture
ISO 13909-2: 2002, Hard coal and coke — Mechanical sampling — Part 2: Coal — Sampling from moving
streams
ISO 13909-4: 2001, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test
samples
ASTM D 6128-00, Standard Test Method for Shear Testing of Bulk Solids Using the Jenike Shear Cell
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 1213-2 and those below apply.
NOTE In this part of ISO 15117, the terms pressure and stress are used synonymously because this convention is
used in research and literature on this subject. Some other terms have not yet been standardized in the literature. These
are listed below, together with a reference to the preferred nomenclature.
3.1
axi-symmetric flow
SEE mass flow
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3.2
bulk density
the mass of a sample of particulate solid including moisture, divided by its total volume
NOTE The level of consolidation stress is critical to any measurement of bulk density.
3.3
bulk material
semi-cohesive particulate material such as coal and other minerals
3.4
cohesion
the shear stress at yield under zero normal stress
NOTE This parameter is not normally quantified.
3.5
compaction
the process of permanent volume reduction of a bulk material by application of a consolidating stress
3.6
consolidation
SEE compaction
3.7
core flow
SEE funnel flow
3.8
critical consolidation, in a shear cell
the state existing in a bulk sample within a shear cell when the cell stem travel becomes independent of
applied shear force
NOTE Under these conditions, the bulk material is deforming without change in voidage. The material is said to be in
its critical state.
3.9
critical state
SEE critical consolidation
3.10
critical pipe or rathole diameter
the diameter of a rathole or pipe at which the rathole or pipe becomes unstable
NOTE The critical rathole diameter varies with consolidation pressures.
3.11
effective angle of internal friction
δ
the angle with the horizontal axis of a line through the origin and tangent to the Mohr circle through the end
point of the yield locus
See Figure 4.
NOTE The line through the origin is called the effective yield locus.
3.12
expanded flow
flow from a bin which has two distinct cross-section regimes
NOTE Funnel flow exists in the lower cylindrical section of the bin whereas mass flow exists in the conical outlet
hopper or hoppers.
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3.13
flow function, instantaneous
FF
for a given bulk material, a plot of the unconfined yield strength σ versus the major consolidating pressure,
c
values being obtained from the yield loci
NOTE This is a measure of the bulk strength or flowability of a bulk material, in a de-aerated state, when first loaded
into a bin or consolidated in a shear cell.
3.14
flow function, time storage
for a given bulk material, a measure of the increase in unconfined yield strength of material subjected to
standard consolidation conditions for a defined time, typically 24 h to 48 h
3.15
funnel flow
the flow that occurs during gravity storage when bulk material sloughs off the surface of the material and
discharges through a vertical channel which forms within the material in the bin whenever material is drawn
from the outlet
NOTE Material adjacent to the bin walls remains stationary.
3.16
hopper half-angle
α
the angle between one wall of the hopper and the vertical
3.17
major consolidating pressure
major consolidating stress
σ
1
the pressure given by the Mohr circle passing through the end point of the instantaneous yield locus and the
tangent to the locus
See Figure 4.
3.18
mass flow
the flow that occurs when bulk material is in motion at every point in a bin whenever material is drawn from the
outlet
NOTE Mass flow is normally symmetric and is usually axi-symmetric in three dimensions in a conical hopper, or
plane in two dimensions in a wedge hopper.
3.19
natural fines
the fraction of the sample screened below 4 mm or 6 mm
3.20
particulate solid
an assembly of solid particles having properties independent of the number of particles present
SEE bulk material (3.3).
3.21
plane flow
SEE mass flow
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3.22
shear apparatus
equipment for subjecting the material under test to shear deformation under conditions of controlled normal
pressure
3.23
unconfined yield strength
σ
c
the major principal stress that must be applied tangentially to an unconfined surface to cause yielding
3.24
voidage or voids ratio
the volume of the voids within a quantity of bulk material, divided by total volume (voids plus solids)
3.25
yield locus, effective
see effective angle of internal friction
3.26
yield locus, instantaneous
the shear force versus normal force curve for plastic failure of an over-consolidated bulk material of given
initial voidage; this defines conditions when material flow commences
3.27
yield locus, time
the shear force versus normal force curve for plastic failure of a bulk material after being held at rest under a
standard pressure for a given time
3.28
yield locus, wall
φ
the locus of shear force versus applied normal force on a sample of bulk material moving in contact with a
boundary surface or wall
NOTE This is the angle determined by the shear and normal force shown in Figure 10.
4 Notation
The following quantity symbols are used in this part of ISO 15117:
F Unconfined yield force under instantaneous conditions
h Compacted height, in bulk density test
S Steady-state shear force during the “shear consolidation” phase of the shear test
S Steady shear force obtained in the wall friction test
f
S An uncorrected value of S determined from the shear test
t
S The value of S selected for a particular level of consolidation, and used for prorating (S ) values
s i t
S Maximum value of shear force obtained during the “sample shear” phase of the shear test
i
()S An uncorrected value of S determined from the shear test
it
()S A corrected value of S obtained using Equation (1)
ip
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V Vertical force due to total vertical load applied at the shear plane during the “shear consolidation” phase
of shear test X
V = V + V
a b
V Vertical force due to the weight of the shear lid, shear ring and bulk solid above the shear plane, i.e.
a
contained within the shear ring
V Vertical force due to the weight applied to the shear lid during the “shear consolidation” phase of the
b
shear test
Vertical force due to the weight applied to the shear lid during the “sample shear” phase of the shear
V
bi
test
V Vertical force applied in the wall friction test
f
Vertical force due to total vertical load applied at the shear plane during “sample shear” phase of the
V
i
shear test
= V +
V V
i a bi
V Vertical force due to the weight applied to the twisting lid during the “preconsolidation” phase of the
t
shear test
V Major consolidating force on sample
1
W Weights used in the wall friction test
f
W Mass of the weight hanger or carrier
h
σ Unconfined yield strength (or stress) of a bulk solid
c
σ Major consolidation pressure (or stress) of a bulk solid
1
φ Wall friction angle
5 Sampling and sample preparation
5.1 Sampling
The sample for flow property analysis shall be taken in accordance with ISO 13909-2. Care should be taken at
all stages of sampling, sample handling and testing to prevent undue breakage.
Where test results are to be used for design of bins and transfer points, the material sampled should be
related to the “problem” i.e., in the state that creates the most difficult flow conditions. For example, where the
material breaks down with time and moisture, a weathered sample should be used.
5.2 Sample preparation
5.2.1 General
Flow property measurements are carried out on the natural fines fraction of the sample. The top size of the
fraction used shall be recorded.
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The sample for testing shall be prepared by the methods given in ISO 13909-4. Sufficient sample shall be
taken to yield at least 1 kg of the natural fines. If, however, time-delayed tests are to be carried out also,
sufficient sample to yield 5 kg of minus 4 mm material is required.
5.2.2 Sample top size
After drying, the sample shall be sieved according to the method set out in ISO 1953 to separate the natural
fines. All tests shall be carried out on the minus 4 mm material occurring naturally in the sample.
5.2.3 Sample division
Where necessary, the sample shall be divided by riffling or mechanical sample division to provide the required
quantity for analysis. Dust loss and size degradation shall be minimized.
5.2.4 Moisture content
In consideration of specific problems, the sample may need to be dry or at a predetermined moisture content.
The screened sample shall be at the required moisture content. The moisture contents of the initial sample
and screened sample shall be measured before and after flow property testing, in accordance with ISO 589,
and should not differ by more than 0,5 % on a mass basis. Samples should be stored in sealed containers to
maintain moisture content. The moisture content of the natural fines in relation to the bulk sample shall be
determined.
6 Determination of yield locus
6.1 Apparatus
A Jenike-type, direct shear tester having provision for the continuous display of shear/deformation using a
chart recorder is required. Standard shear cells (see Figure 1) have internal diameters of 95 mm or 63,5 mm.
The lower ring is fixed to the frame and the upper ring is free to move under the action of the applied force.
Ring movement is resisted by the material under test in the shear cell. To carry out the test, a twisting lid,
shear lid, mould ring, twisting wrench, weight carrier, weights, spoon, scraper and brush are required. The
standard deformation rate is (2,5 ±0,2) mm/min.
Where preconsolidation pressures are above 50 kPa, a cell of 63 mm nominal inside diameter cell is preferred.
The shear cell of smaller diameter permits the higher pressures to be generated with smaller, more
manageable normal loads. The cell diameter used should be a part of any statement of results.
NOTE Strict comparison is possible only on results from cells of the same dimensions.
6.2 Instantaneous yield locus
6.2.1 General
The instantaneous yield locus is determined using the 95 mm low pressure cell (see 6.1). The shear cell shall
be filled with a fresh sample for each test.
To ensure that the cell material is critically consolidated when measurements are made, the limited travel in
the Jenike cell necessitates an iterative trial-and-error consolidation procedure. Critical consolidation is the
point where cell stem travel is first independent of shear force as shown in Figure 3, curve B.
The trial-and-error procedure shall approach critical consolidation from below rather than above, as the latter
can lead to erroneous results (see Figure 3, curve C, point X).
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6.2.2 Preconsolidation of the sample
Place the cell base, shear ring and mould ring on the shear tester (see Figure 1). Adjust the offset of the shear
ring to approximately 3 mm.
Place a sample of the material to be tested in the shear cell, layer by layer, each layer being spread lightly and
uniformly with a spoon, taking care not to leave impressions which could lead to preferential shear planes.
Scrape off excess material flush with the top of the mould ring. Cover the material with the twisting lid.
Apply a vertical force, V , to the twisting lid by means of a weight carrier, and, by using the special twisting
t
wrench, apply a number of oscillating twists (amplitude approximately ± 20°) to the lid. During this procedure,
care should be taken not to press down on the twisting lid and not to impede the motion of the shear ring, as it
tends to follow the motion of the twisting lid.
Select the value of V and the number of twists to be applied by trial and error. For most dry samples, V is
t
t
made equal to V, the normal force used in the consolidation-under-shear procedure described below.
However, for high moisture samples, values of V equal to 2 to 4 times V may be required. The number of
t
complete twists applied initially is about 20.
Remove the weight carrier from the twisting lid.
Lift off the mould ring while holding down the twisting lid and shear ring.
Slide the twisting lid off and scrape off the excess material flush with the top of the shear ring. In these
operations, care should be taken to avoid any movement of the shear ring. Clean away excess material with
the brush.
Key
1 twisting lid
2 mould ring
3 shear ring
4 base
5 frame
a
Offset.
Figure 1 — Jenike shear cell — Set-up for preconsolidation
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6.2.3 Shear consolidation
Consolidation of the sample is completed by a shearing operation, which causes the material to flow under the
consolidating stresses until a steady-state shear value is reached, or closely approached.
Place the shear lid on the sample, taking care to centre it within the shear ring, and ensure that the drive
bracket is aligned with the transducer stem. Apply the force, V , to the lid using an appropriate weight, and
b
advance the stem of the direct shear tester against the bracket (see Figure 2).
Allow shearing to proceed until a condition is reached where a layer of the material across the whole sample
is caused to flow plastically, and the recorded shear force reaches a steady value, S. Ideally, this steady value
of shear force should be reached when the shear ring is concentric with the base of the cell.
Reverse the stem travel until the shear force drops to zero. Then remove the force, V .
b
It is important that the steady-state shear force, S, is reached as indicated by curve B, Figure 3; the sample is
then critically consolidated. If the shear force continues to rise for the complete stem travel (curve A, Figure 3),
the sample was under-consolidated during the preconsolidation phase. Generally, this means that an increase
is needed in the preconsolidation force, V, or the number of twists used. If the shear force reaches a
t
maximum then reduces (curve C, Figure 3), the sample was over-consolidated during the preconsolidation
phase. Generally, this means that either the value of V or the number of twists was excessive. If either of
t
these conditions occurs, the test should be repeated.
Key 5 frame
1 shear lid 6 bracket
2 shear ring 7 loading stem
3 shear plane 8 pin
a
4 base Offset.
Figure 2 — Jenike shear cell — Set-up for shear consolidation
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Key
A under-consolidated
B critically consolidated
C over-consolidated
X Stem travel
Y Shear force, S (N)
a
Limit of travel.
Figure 3 — Types of shear consolidation curve
6.2.4 Shearing of the sample
The third stage of the test is the actual shearing of the sample under force , smaller than V. The procedure
V
i
shall be as given below.
Apply force ( ) to the shear lid.
V
bi
Advance the stem of the machine until it almost touches the bracket.
Let shearing proceed until the recorder pen reaches and passes a maximum value, S .
i
Retract stem and remove force, .
V
bi
Remove the entire cell including the shear lid and split the shear ring and base apart. Striking the lid or bottom
of the cell, check to see that the shear plane is between the ring and the base and not angled up or down. If
the shear plane is not correct, the complete test shall be repeated.
Once for each level of consolidation, determine the additional vertical force (V ) above the shear plane.
a
NOTE V is the vertical force due to
a
a) shear lid,
b) shear ring, and
c) mass of material contained within the ring.
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6.2.5 Determination of the complete family of instantaneous yield loci
Repeat the entire three-stage procedure two more times for the same level of consolidation, applying the force,
V , to the shear lid during
...
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