ICS 65.060.01
Reference number
DRS 268-3: 2020
© RSB 2020
RWANDA STANDARD
DRS
268-3
2nd edition
2020-June
Agroprocessing machines — Specification —
Part 3:
Rice mill
DRS 268-3: 2020
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Contents Page
Foreword .......................................................................................................................................................... 3iv
1 Scope ................................................................................................................................................... 51
2 Normative references ......................................................................................................................... 51
3 Terms and definitions ........................................................................................................................ 51
4 Classification ....................................................................................................................................... 62
5 Material of construction ..................................................................................................................... 73
6 Performance and safety requirements ............................................................................................. 73
7 Workmanship and finish .................................................................................................................... 84
8 Maintenance and operation ............................................................................................................... 84
9 Sampling and testing ......................................................................................................................... 84
10 Marking ................................................................................................................................................ 84
DRS 268-3: 2020
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Foreword
Rwanda Standards are prepared by Technical Committees and approved by Rwanda Standards Board (RSB) Board of Directors in accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT agreement on the preparation, adoption and application of standards.
The main task of technical committees is to prepare national standards. Final Draft Rwanda Standards adopted by Technical committees are ratified by members of RSB Board of Directors for publication and gazettment as Rwanda Standards.
DRS 268-3 was prepared by Technical Committee RSB/TC 047, Steel aluminium and related products.
In the preparation of this standard, reference was made to the following standard (s):
1) XYZ: Title
2) XYZ: Title
The assistance derived from the above source is hereby acknowledged with thanks.
This second edition cancels and replaces the first edition (RS 268-3: 2015) which has been technically revised.
DRS 268 consists of the following parts, under the general title Agroprocessing machinery — Specification:
Part 1: Rice thresher
Part 2: Power operated maize sheller
Part 4: Heated air mechanical grain dryer
Part 5: Maize mill
Committee membership
The following organizations were represented on the Technical Committee on Title of TC (RSB/TC nnn) in the preparation of this standard.
University of Rwanda/college of science and technology
University of Rwanda/College of agriculture animal science and veterinary medicine
Kabizu business group
Rwanda Polytechnic/IPRC Kigali
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Rwanda Polytechnic/IPRC Ngoma
Rwanda Polytechnic/IPRC Musanze
RWANTECH Boilers
Rwanda Inspectorate and competition authority
Rwanda Institute for Conservation Agriculture
ACER Ltd
Rwanda Standards Board (RSB) – Secretariat
DRS 268-3: 2020
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Agroprocessing machines — Specification — Part 3: Rice mill
1 Scope
This Draft Rwanda Standard specifies the classification, requirements, sampling and methods of test for rice mill.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.
DRS 269-3, Agroprocessing machines — Test methods — Part 3: Rice mill
DRSRS 241, Agriculture machinery — Methods of sampling
RS 236, Acoustics — Noise pollution — Tolerance limit
RS 340, Food processing machines — Specifications
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply
3.1
bran
outer layer of the brown rice consisting of the aleurone cells covering the endosperm of the rice grain
3.2
broken grains
grains that broken in the process of milling which have a size of less than eight-tenth (8/10) of the average length of whole grain
3.3
coefficient of hulling
measure of the ability of the machine to remove the hulls
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3.4
coefficient of wholeness
measure of the ability of the machine to remove the hulls without breaking the grain
3.5
head rice
grain or fraction of grain with its length equal to or greater than eight per tenth (8/10) of the average length of the whole grain
3.6
hulling efficiency
product of the coefficient of hulling and the coefficient of wholeness of grains, expressed in percent
3.7
input capacity
weight of palay per unit loading time into the hopper/intake pit, expressed in kilogram per hour
3.8
milling degree
extent or degree by which the bran layer of the brown rice is removed as a result of whitening
3.9
percent head rice
ratio of the weight of grains that do not break in the process of milling and with a size of three-fourth (3/4) or more of the whole grain to the total weight of milled rice, expressed in percent
3.10
percent head rice index
ratio of the percent head rice obtained in actual testing, to the percent head rice obtained from the laboratory test mill.
4 Classification
A paragraph.
The rice mill shall be classified based on the following:
a) method of operation; and
DRS 268-3: 2020
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1. single-pass rice mill; and
2. multi-pass rice mill
b) type of huller
1. under-runner stone disc; and
2. rubber roll type
5 Material and construction
5.1 Food zone area shall be made from food grade materials.
5.2 Non-food zone area may be made from carbon steel that has been rendered corrosion resistant
5.3 Construction of rice threshing machine shall be done in accordance with RS 340.
6 Performance and safety requirements
6.1 The performance criteria for rice mill shall be as specified in Table 1
Table 1 — Performance criteria for rice mill
criteria Performance
Single Pass Multi Pass
Cono Rubber roll Cono Rubber roll
Milling Recovery
Index, min.
0.97 0.98 0.97 0.98
Percent Head Rice
Index, min. 0.90 0.90 0.90 0.90
Hulling Efficiency
percent, min. 80 80 80 80
Milling Degree Well milled
6.2 The specified capacity at the brown rice output of the paddy separator shall be attained, with maximum of 10 pieces of palay per kilogram of brown rice output.
6.3 Lubrification shall be provided for non-sealed type bearings and belt tightening.
6.4 Provisions for safety of the operator from all moving components of the rice mill such as belt guard or cover shall be included.
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6.5 6.2 The maximum level for Noise Level, [db] (A) for threshing machine shall be as specified in RS 236.
7 Workmanship and finish
7.1 Rice mill shall be free from manufacturing defects that may be detrimental to its operation.
7.2 Any uncoated metallic surfaces shall be free from rust and shall be painted properly with food grad paint for metallic in contact with rice.
7.3 Rice mill shall be free from sharp edges and surfaces that may injure the operator.
7.4 Rice mill shall be constructed to ease to operation and cleaning
8 Maintenance and operation
8.1 Each rice mill shall be provided with a set of relevant mechanic tool kit.
8.2 An instruction manual (User’s manual, parts catalogue and service manual) shall be provided.
8.3 All components that require regular maintenance, servicing and adjustment should be easily accessible.
9 Sampling and testing
9.1 The rice mill shall be sampled for testing in accordance with RS 241.
9.2 The sampled rice mill shall be tested in accordance with RS 269-3.
10 Marking
Rice mill shall be indelibly and legibly marked with the following information in one of three official languages used in Rwanda:
a) Name and registered trademark of the manufacturer;
b) brand;
c) model;
d) serial number;
e) country of manufacture;
f) input capacity, kg/h;
g) rating power, kW;
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h) production capacity
DRS 268-3: 2020
Price based on nnn pages
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