INTERNATIONAL ISO

STANDARD 3684
Second edition
1990-03-15

Conveyors belts - Determination of minimum

pulley diameters

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Courroies transporteuses - D& termina tion des diam& tres minimaux des tambours

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ISO 3684:1990
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ab8eb70262f6/iso-3684-1990

Reference number
ISO 3684 : 1990 (El
ISO 3684 : 1990 (El

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. Esch 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, govern-
mental 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.

Draft International Standards adopted by the technical committees are circulated to

the member bodies for approval before their acceptance as International Standards by
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the ISO Council. They are approved in accordance with ISO procedures requiring at
least 75 % approval by the member bodies voting.

International Standard
(standards.iteh.ai)
ISO 3694 was prepared by Technical Committee ISO/TC 41,
Pulle ys and belts (including veebelts).
ISO 3684:1990
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This second edition cancels and replaces the first edition ab8eb70262f6/iso-3684-1990
(ISO 3684: 1976), of which it
constitutes a technical revision.

0 ISO 1990
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
International Organkation for Standardkation
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
INTERNATIONAL STANDARD ISO 3684 : 1990 (E)

Conveyor belts - Determination of minimum puHey

diameters

1 Scope agreements based on this International Standard are encouraged

to investigate the possibility of applying the most recent editions
This International Standard establishes a method of calculating of the Standards indicated below. Members of IEC and ISO main-
minimum pulley diameters for conveyor belts. tain registers of currently valid International Standards.

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3 : 1973, Preferred numbers - Series of preferred numbers.
lt applies to belts made of rubber or plastics with textile or
metal carcasses, of different carcass thickness and different
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ISO 583: 1975, Conveyor belts - Jolerances on total thickness
carcass materials, operating at any anticipated belt tension up
and thickness of covers.
to, but not exceeding, the maximum belt tension (RMBT).

ISO 3684:1990ISO 1536 : 1975, Con tinuous mechanical handling equipment

lt does not apply either to belts which have a carcass thickness
of more than 20 mm or to those which have intermediate layers for loose bulk ma terials - Jroughed belt conve yors (o ther than
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of rubber or plastics of more than 0,8 mm thickness ab8eb70262f6/iso-3684-1990 conveyors) - Belts.
between portable
the plies.
ISO 7590 : 1988, Steel Cord conveyor belts - Cover thickness
Nor does it apply either to heat-resistant belts on conveyors for measuremen t.
hot products at temperatures over 100 OC or to belts in Service
at ambient temperatures under -40 OC.
3 Definitions
The use on conveyor belts of pulleys with diameters too small
for the carcass construction may lead to premature belt failure.
3.1 Belt structure
NOTES
3.1.1 thickness of fabric carcass, h,: as defined by
1 The values indicated in this International Standard are minimum
values to be used in the absence of information provided by the con-
ISO 583.
veyor belt manufacturer.
2 The calculation of the minimum pulley diameter according to this 3.1.2 thickness of steel cord carcass, dz: as defined by
International Standard is valid for all general applications. For special ISO 7590.
purposes, the conveyor belt manufacturer may allow smaller pulley
diameters. For belts which are not listed in the following tables, consult
the manufacturer. 3.2 Types of pulley
3 In the case of use of pulleys with diameters larger than those cor- Figures 1 to 4 show the different types of pulley for conveyor
responding to the minimum diameter calculated fqr the recommended belts.
maximum belt tension, an increase of this maximum tension is not per-
missible.
A: Driving pulleys and pulleys exposed to high belt tension,
for example :
2 Normative references - main driving pulley at the head or tail;
The following Standards contain provisions which, through - delivery pulleys under full tension;
reference in this text, constitute provisions of this International
- loop pulleys in the tripper;
Standard. At the time of publication, the editions indicated
were valid. All Standards are subject to revision, and Parties to - terminal head pulleys in the case of tail driving, etc.

1
ISO 3684 : 1990 (E)

B: Snub pulleys in the return run under lower tension, for where
example :
e is the thickness of the carcass, in millimetres;
- terminal tail pulleys in the case of head driving;
C is the factor for the carcass material, from table 2.
- terminal head pulleys for downward conveying if the
terminal tail pulley is braked;
- snub and bend pulleys in take-up devices. Table 2 - Factor C

Carcass material I C
C: Bend pulleys, for a Change of direction of the belts of less
than 30°. Cotton 80
Polyamide 90
3.3 Pulley diameter
Gotton/ Polyamide 90
pulley diameter: The Overall diameter of the pulley, disregar- Gotton/ Polyester 98
ding protective layers made of rubber, ceramic or similar
Polyester 108
material if they are exposed to wear.
Rayon 118
For crowned pulleys, the smallest diameter shall be at least the Steel cord 145
specified minimum.

The pulley diameters calculated using this formula shall be

4 Pulley diameters rounded up to the next larger Standard pulley diameter (RIO or
R20 series of preferred numbers according to table 1).
The pulley diameters follow the Steps of the RIO (or R20 for
1 400 mm and 1 800 mm) series of preferred numbers given in
ISO 3 (see table 1).
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5.2 Influence of the type of pulley

Table 1 - Pulley diameters (standards.iteh.ai)

In Order to take the type of pulley into account, it is possible to
choose smaller Standard pulley diameters from the series of
Dimensions in millimetres
preferred numbers according to table 3.
100 630 ISO 3684:1990
125 https://standards.iteh.ai/catalog/standards/sist/0181a6eb-058d-44ca-8ad3-
800
160 1000 ab8eb70262f6/iso-3684-1990
Table 3 - Diameters according to pulley type
200 1250
Type of
250 (1 400) Pulley diameter
pulley
315 1600 (see 3.2)
400 (1 800)
I A 1 Standard pulley diameter according to 5.1
500 2000 B One step lower in the RIO series of Standard
pulley diameters than the diameter for type
This table includes, in particular, all the values fixed by of pulley A (but see 5.4.1)
ISO 1536. C Two Steps lower in the R10 series of stan-
dard pulley diameters than the diameter for
type of pulley A (but see 5.4.2)
5 Determination of the recommended
minimum diameter
5.3 Influence of belt tension
5.1 Formula
In Order to take the effect of belt tension (as a percentage of the
The pulley diameter, D, in millimetres, is given by the formula recommended maximum belt tension, RMBT) into account, it
is possible to choose smaller Standard pulley diameters from
D= exc the series of preferred numbers according to table 4.
 ISO 3684 : 1990 (El

Table 4 - Diameters according to belt tension diameters below that which results from 5.1 (pulley type A at
60 % to 100 % of RMBT). i
Percentage
of the
recommended Pulley diameter 5.42 No pulley of type C for a conveyor belt shall have a
maximum belt diameter smaller than three Steps in the RIO series of Standard
tension used diameters below that which results from 5.1 (pulley type A at
60 % to 100 % of RMBT).
Standard pulley diameter according to 5.1
100 % of RMBT
For example :
over 30 % up to One step lower in the RIO series of Standard
60 % of RMBT pulley diameters than the pulley diameters
for “60 % up to 100 %” Table 5 - Pulley diameters
Two Steps lower in the RIO series of stan- Dimensions in millimetres

-1
dard pulley diameters than the pulley Percentage of the Pulley types
diameter for “60 % up to 100 %” (but see recommended maximum
5.4.1 and 5.42) belt tension used A I B I C
1 over 60 % up to 100 % of RMBT 1 1 000 1 800 1 630
1 over 30 % up to 60 % of RMBT 1 800 1 630 1 500 1
5.4 Combination of influences and limitations
1 up to 30 % of RMBT 1 630 1 630 1 5Oö1
The possibilities for reducing the pulley diameters because of
the influence of the type of pulley according to 5.2, and the belt
tension according to 5.3, may be considered at the same time. 6 Summary
However, pulley diameters which are too small shall be
avoided. For this reason, the following limitations shall be In table 6, the minimum pulley diameters have been calculated
observed. in accordance with clause 5, for different carcass thicknesses
and materials, for different types of pulleys and for different
iTeh STANDARD PREVIEW belt tensions. The table does not constitute a limitation on
5.4.1 No pulley of type B for a conveyor belt shall have a larger pulley diameters, which may result in longer Service from
(standards.iteh.ai)
diameter smaller than two Steps in the RIO series of Standard the belting used.

ISO 3684:1990
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ab8eb70262f6/iso-3684-1990

3
ISO 3684 : 1990 (EI

Figure 3

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Figure 2

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ab8eb70262f6/iso-3684-1990

Figure 3

k
&c A
Figure 4

= Driving pulley 0 = Non-driving pulley

4
 iTeh STANDARD PREVIEW
c
(standards.iteh.ai) Table 6 - Summary
Dimensions in millimetres
Material of the warp
ISO 3684:1990 Percentage of the RMBT used
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Polyamide ab8eb70262f6/iso-3684-1990 over 60 % up to 100 % over 30 % up to 60 % up to 30 %
Gotton/ Rayon Steel cord
Cotton and cotton/ Polyester Types of pulley
Polyester
Polyamide
(1d = 80 c = 90 C = 98 C = 108 C= 118 c = 145 A B 1 C A B
Carcass thickness
commen ed minim Jm diame
fr0 rnl to I from to Ifrom to 1from 1 to from to from to
7--
12 IJ 1 03 W3 W3 100
1,3 1,5 12 lt3 IJ 12 1 IJ 03 1 OJ 018 125 100 100
1,6 2 14 1‘7 lt3 V 12 L4 IJ L3 03 IJ 160 125 100 125 100 100 100
2 ,I 2,5 lt8 22 117 2 L5 lt43 19 M 12 1,3 200 160 125 160 125 100 125 125 100
2 ,6 311 213 2,7 71 2,5 13 2,3 L7 211 L4 L7 200 160 200 160 125 160 160 125
32 33 23 315 2,6 3,2 2,4 23 22 216 13 Zl 250 200 250 200 160 200 200 160
4 5 316 49 3,3 4 3 3,7 2,7 3,3 22 2,7 315 250 315 250 200 250 250 200
5J 62 4,5 5,5 4,1 5J 3,8 4,6 3,4 42 218 314 400 315 400 315 250 315 315 250
6 ,3 7,8 516 7 5,2 6,4 417 5,8 4,3 5,3 315 4,3 630 500 400 500 400 315 400 400 315
7 ,9 10 711 w3 6,5 61 53 714 5,4 617 414 5,5 800 630 500 630 500 400 500 500 400
10,l 12,5 83 11,l 82 IO,2 7,5 92 68 814 5,6 63 1 000 800 630 800 630 500 630 630 500
12,6 15,6 11,2 13,8 IO,3 12,7 93 11,5 815 IO,5 7 w3 1250 1 060 800 1 000 800 630 800 800 630
15,7 17,5 13,9 15,5 12,8 14,2 11,6 12,9 IO,6 11,8 817 W 1400 1250 1000 1 250 1 000 800 1 000 1 000 800
17,6 20 15,6 l7,7 14,3 16,3 13 14,8 11,9 13,5 917 11 1 600 1 250 1000 1 250 1 000 800 1 000 1 000 800
17‘8 20 16,4 18,3 14,9 16,6 13,6 15,2 11,l 12,4 1800 1400 1250 1400 1 250 1 000 1250 1250 1 000
I / 18,4 20 16,7 18,5 15,3 16,9 12,5 13,8 2000 1 600 1 250 1 600 1 250 1000 1250 1 250 1 000
EX,arnp/e of reading: Carcass belt with Polyester warp of 4 mm thickness, working on a driving pulley (type A) at 75 oh of RMBT: recommen&d minimum diameter = 500 mm,

m
ISO 3684 : 1990 (El

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ISO 3684:1990
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ab8eb70262f6/iso-3684-1990

UDC 621 n5.051 : 621.867.2

Descriptors : conveyors, belt conveyors, belts, conveyor belts, pulleys, dimensions, diameters.

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