ICS 65.060.01  
 
Reference number  
DRS 269 -2: 2020  
© RSB2020  
  
 RWANDA 
STANDARD  DRS  
269-2 
 
2nd edition  
2020 -June  
 
Agroprocessing machines — Test methods 
— 
Part 2 : Power operated maize sheller  
   
DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB2020  
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 
prior written permission from R SB. 
Requests for permission to reproduce thi s document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
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Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 269 -2: 2020  
iii                ©RSB2020 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ....................  vii 
2 Normative references  ................................ ................................ ................................ ..........................  vii 
3 Terms an d definitions  ................................ ................................ ................................ .........................  vii 
4 General conditions for test and inspection  ................................ ................................ .....................  viii 
4.1 Role of manufacturer/dealer  ................................ ................................ ................................ ..............  viii 
4.2 Test site conditions  ................................ ................................ ................................ ............................  viii 
5 Susp ension of test  ................................ ................................ ................................ .............................  viii 
6 Test preparation  ................................ ................................ ................................ ................................ . viii 
6.1 Running -in and preliminary adjustments  ................................ ................................ ........................  viii 
6.2 Test materials  ................................ ................................ ................................ ................................ ..... viii 
7 Pre-test observation  ................................ ................................ ................................ ...........................  viii 
8 Performance test  ................................ ................................ ................................ ................................ .. ix 
8.1 Operation of the maize mill  ................................ ................................ ................................ .................  ix 
9 Test trial  ................................ ................................ ................................ ................................ .................  ix 
10 Sampling  ................................ ................................ ................................ ................................ ...............  ix 
10.1  Data collection  ................................ ................................ ................................ ................................ ...... ix 
10.1.1  Duration of test  ................................ ................................ ................................ ................................ ..... ix 
10.1.2  Noise level  ................................ ................................ ................................ ................................ .............  ix 
10.1.3  Speed of components  ................................ ................................ ................................ ..........................  ix 
10.1.4  Air velocity  ................................ ................................ .............................. Error! Bookmark not defined. ix 
10.1.5  Fuel consumption  ................................ ................................ ................................ ...............................  ixx 
10.1.6  Data recording and observations  ................................ ................................ ................................ ........  x 
11 Laboratory analysis  ................................ ................................ ................................ ...............................  x 
12 Data analysis  ................................ ................................ ................................ ................................ ..........  x 
13 Test report  ................................ ................................ ................................ ................................ ..............  x 
Annex  A (normative)  Test materials for power operated maize sheller  ................................ .................  xixii 
A.1 Sample characteristics  ................................ ................................ ................................ ....................  xixii 
A.2 Quantity to be supplied ................................ ................................ ................................ ....................  xixii 
A.3 Sample preparation  ................................ ................................ ................................ ..........................  xixii 
Annex  B (normative)  Specifications of power operated maize sheller  ................................ .................  xiixiii 
Annex  C (normative)  Sampling and measurements for test material  ................................ ...................  xvxvi 
C.1 Sampling from different outlets  ................................ ................................ ................................ .... xvxvi 
C.2 Collection of scattered maize kernels  ................................ ................................ ..........................  xvxvi 
C.3 Handling of samples  ................................ ................................ ................................ ......................  xvxvi 
C.4 Other measurements required during the test run  ................................ ................................ ... xvixvii 
C.5 Measurement of fuel consumption  ................................ ................................ .............................  xvixvii DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  iv 
 Annex  D (normative)  Performance test data sheet  ................................ ................................ ............  xviixviii  
Annex  E (normative)  Laboratory analysis  ................................ ................................ ...............................  xxxxi 
E.1 Measurement of ear maize dimensions  ................................ ................................ .......................  xxxxi 
E.2 Measurement of kernel -ear maize ratio  ................................ ................................ .......................  xxxxi 
E.3 Determination of Purity  ................................ ................................ ................................ .................  xxxxi 
E.4 Determination of losses  ................................ ................................ ................................ ................  xxxxi 
E.4.1  Blower loss  ................................ ................................ ................................ ................................ ..... xxxxi 
E.4.2  Separation loss  ................................ ................................ ................................ ..............................  xxxxi 
E.4.3  Unsh elled loss  ................................ ................................ ................................ ..............................  xxixxii 
E.4.4  Scattering loss  ................................ ................................ ................................ .............................  xxixxii 
E.5 Determination of net percent cracked kernels  ................................ ................................ .........  xxixxii 
E.6 Determination of percent mechanically damaged kernels  ................................ ......................  xxixxii 
Annex  F (normative)  Laboratory grain analysis data sheet  ................................ ..............................  xxiixxiii  
F.1 Crop conditions  ................................ ................................ ................................ .........................  xxiixxiii  
F.2 Kernel -ear maize ratio  ................................ ................................ ................................ ..............  xxiiixxiv  
Anne x G (normative)  Formula used during calculations and testing  ................................ ..............  xxvxxvi  
 DRS 269 -2: 2020  
v                ©RSB2020 - All rights reserved  
 Foreword  
Rwanda Standards are prepared by Technical Committees and approved by Rwanda Standard s 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.  
RS 269 -2 was prepared by Technical Committee RSB/TC 047  Steel  aluminium and related product  
This second  edition  cancels and replaces the first  edition (RS  269-2:2015 ), which has been technically 
revised.  
DRS  269 consists of the following parts, under the general title Agroprocessing machinery — Test methods : 
 Part 1:  Rice thresher  
Part 3: Rice mill  
 Part 4  Heated air mechanical grain dryer  
Part 5: Maize mill  
Committee membership  
The following organizations were represented on the Technical Committee on Steel aluminium and related 
(RSB/TC 047) 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  
Rwanda Polytechnic/IPRC Ngoma  
Rwanda Polytec hnic/IPRC Musanze  
RWANTECH Boilers  DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  vi 
 Rwanda Inspectorate and competition authority  
Rwanda Institute for Conservation Agriculture  
ACER Ltd  
Rwanda Standards Board (RSB) – Secretariat  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DRS 269 -2: 2020  
vii                ©RSB2020 - All rights reserved  
 Agricultural machinery — Test methods — Part 2: Power operated maize 
sheller  
1 Scope  
This Draft Rwanda Standard specifies the methods of sampling, testing and inspection for power operated 
maize sheller.  
2 Normative references  
The following referenced documen ts 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.  
DRS 268 -2, Agroprocessing machines —Specification — Part 2: Power operated maize sheller  
RS 241, Agricultural machinery — Methods of sampling  
3 Terms and definitions  
For the purposes of this standard, the terms and definitions given in RS 268 -2 and t he following apply.  
3.1 
concave clearance  
clearance between cylinder shelling elements and concave component  
3.2 
corrected capacity  
actual capacity of the sheller corrected at 20 % kernel moisture content (wet basis), and 100 % purity  
3.3 
output capacity  
weight  of shelled kernel collected per unit of time  
3.4 
total kernel input  
sum of the weight of collected shelled kernels and all the shelling losses  DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  viii 
 4 General conditions for test and inspection  
4.1 Role of manufacturer/dealer  
The manufacturer/dealer shall comply with  the test procedures of national testing authority.  
4.2 Test site conditions  
The maize sheller shall be installed on a stable level ground on a site with sufficient working space, and shall 
be positioned in such a way that the wind cannot blow the maize cobs a nd other impurities into the clean 
kernel.  
5 Suspension of test  
5.1 If during the test run, the machine stops due to breakdown or malfunction so as to affect the machine’s 
performance, the test may be suspended.  
5.2 The decision to suspend or to continue th e test is at the discretion of the testing authority and concurred 
by the manufacturer’s representative.  
6 Test preparation  
6.1 Running -in and preliminary adjustments  
6.1.1  Before the start of the test, the maize sheller shall have undergone a breaking -in period .  
6.1.2  The maize sheller shall be operated at the test site for sufficient duration with and without load.  
6.1.3  During the running -in period, the various adjustments of the maize sheller shall be made according to 
the manufacturer’s recommendations.  
6.1.4 No other adjustments shall be permitted while the test is ongoing.  
6.2 Test materials  
The maize to be used in the test shall be prepared in sufficient quantity, using the procedure given in Annex A.  
7 Pre-test observation  
7.1.1  The specifications claimed b y the manufacturer and the physical details given in Annex B shall be 
verified by the recognized testing authority.  
7.1.2  A stable and level surface shall be used as reference plane for verification of dimensional machine 
specifications.  DRS 269 -2: 2020  
ix                ©RSB2020 - All rights reserved  
 8 Performance test  
8.1 Operation of the maize mill  
8.1.1  The maize sheller shall be operated at the recommended speed and feed rate of the manufacturer.  
8.1.2  The same feeding rate recommended by the manufacturer shall be maintained during the test run.  
8.1.3  After the test -run, the shelling area shall be cleaned and then prepared for the next test trial(s).  
8.1.4  This procedure shall be repeated for at least three test trial(s).  
9 Test trial  
A minimum of two (2) test trials, with duration of at least 15 min per trial, shall be ad opted.  
10 Sampling  
Sampling procedure is given in Annex C.  
10.1 Data collection  
10.1.1  Duration of test  
The duration of each test trial shall start with the feeding of the first sample and ends after the feeding of the 
last sample. However, all discharge from the differe nt outlets shall be included after the cut -off time.  
10.1.2  Noise level  
10.1.2.1  The noise emitted by the machine, with or without load, shall be measured using a noise level 
meter at the location of the operators and baggers.  
10.1.2.2  The noise, expressed in db (A), shall be measured in accordance with RS 236.  
10.1.3  Speed of components  
The speed of the shelling cylinder, oscillating screen shaft, fan shaft, prime mover and other rotating 
components shall be measured using a tachometer.  
10.1.4  Fuel consumption  
Before the start  of each test trial, the fuel tank shall be filled to its capacity and after each test trial, the fuel 
consumed shall be measured by refilling the tank to the same level using a graduated cylinder measured in 
L/hr. DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  x 
 10.1.5  Data recording and observations  
Record sh eet for all data and information during the test is given in Annex D . 
11 Laboratory analysis  
The laboratory procedures to be followed in the analysis are given in Annex E  and the data sheet to be used 
is given in Annex F.  
12 Data analysis  
12.1 For uniform result  of output due to variation in kernel moisture content and purity, the output capacity 
shall be corrected at 100 % purity and 20 % moisture content.  
12.2 The formula to be used in the calculation of different test parameters are given in Annex G.  
13 Test repo rt 
The test report shall include the following information:  
a) title; 
b) summary of result;  
c) methods of test;  
d) conditions of the machine;  
e) description of the machine;  
1) figure 1 – material flow diagram  
2) figure 2 – power transmission system  
3) figure 3 –arrangements of s helling elements on the cylinder  
4) table 1 – machine specifications  
f) results of test;  
g) table 2 – field performance test data;  
h) observations (include pictures); and  
i) name and signature of test engineers  DRS 269 -2: 2020  
xi                ©RSB2020 - All rights reserved  
 Annex  A 
(normative)  
 
Test materials for power operated maize shelle r 
A.1 Sample characteristics  
Test materials to be used shall have the following characteristics:  
a) variety: commonly or locally grown;  
b) moisture content: 18 % - 24 %, wet basis; and  
c) kernel -ear maize ratio: 0.77 – 0.81.  
A.2 Quantity to be supplied  
The amount of test material to be supplied shall be sufficient for at least three hour of continuous shelling 
operation including samples to be used for running -in prior to the actual conduct of test trials.  
A.3 Sample preparation  
Prepare the sample in such a way that test sample to be used for the running -in and in each test trial shall 
have identical characteristics in terms of moisture content, variety and date of harvest and cultural 
management practices such as water management, fertilizer input.  
 DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xii 
 Annex  B 
(normative)  
 
Specific ations of power operated maize sheller  
Name of Applicant (or Distributor): _____________________________________________  
Address: ___________________________________________________________________  
Telephone No: ____________________________________________ __________________  
Name of Factory/Distributor: __________________________________________________  
Address: __________________________________________________________________  
General information  
Make: _____________________ Brand/Model: ____________________ _______________  
Serial No: _____________________ Classification: ________________________________  
Production date of machine sheller to be tested: ___________________________________________  
Table B 1 — Items to be inspected  
Manufacturer’s Items  Manufactur er’s 
Specifications  Verification by the  
testing Agency  
B.1 Dimensions and weight of sheller    
B.1.1 Overall length (mm)    
B.1.2 Overall width (mm)    
B.1.3 Overall height (mm)    
B.1.4 Weight of the machine (kg), without 
engine    
B.2 Crop(s) for which machine is suitable    
B.3 Rated output capacity (kg/h)    
B.4 Recommended cylinder speed (rpm)    
B.5 Engine    
B.5.1 Brand    
B.5.2 Model    
B.5.3 Serial Number    DRS 269 -2: 2020  
xiii                ©RSB2020 - All rights reserved  
 B.5.4 Make    
B.5.5 Rated power (kW)    
B.5.6 Rated speed (rpm)    
B.5.7 Type    
B.5.8 Weight    
B.5.9 Starting system    
B.5.10 Cooling system    
B.6 Type of power transmission system    
B.6.1 Engine to    
B.6.2 Cylinder shaft to    
B.6.3 Fan shaft to    
B.6.4 Oscillating sieve/screen to    
B.6.5 Others (specify)    
B.7 Shelling Cylinder    
B.7.1 Type    
B.7.2 Size (L x D), mm    
B.7.3 Cylinder teeth    
B.7.3.1 Type    
B.7.3.2 Size    
B.7.3.3 Number/row    
B.7.3.4 No. of rows    
B.7.3.5 Arrangement    
B.7.3.6 Means of attachment    
B.7.3.7 Material    
B.7.3.8 Others    
B.7.4 Material    
B.8 Fan    
B.8.1 Type    
B.8.2 No. of units    
B.8.3 Impeller    
B.8.3.1 Material    
B.8.3.2 Number of blades    
B.9 Oscillating screen    
B.9.1 Dimension (L x W), mm    
B.9.2 Size of perforations, mm    
B.9.3 Length of stroke, mm    
B.9.4 Material    
B.10 Concave component    DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xiv 
 B.10.1 Overall diameter, mm    
B.10.2 Clearance    
B.10.2.1Maximum, mm    
B.10.2.2Minimum, mm    
B.10.3 Material    
B.11 Hopper (if available)    
B.11.1 Location    
B.11.2 Material    
B.11.3 Feature    
B.12 Feeding Table (if available)    
B.12.1 Dimensions (L x W), mm    
B.12.2 Height from the ground (mm)    
B.12.3 Orientation    
B.12.4 Mode of attachment    
B.12.5 Material    
B.13 Transport device    
B.13.1 Type    
B.13.2 Size    
B.14 Safety device(s), if any    
B.15 Discharge device    
B.16 Labour requirement    
B.17 Adjustment(s)    
B.18 Other special features    
 
 DRS 269 -2: 2020  
xv                ©RSB2020 - All rights reserved  
 Annex  C 
(normative)  
 
Sampling and measurements for test material  
C.1 Sampling from different outlets  
C.1.1  During each test trial, samples shall be collected from the different outlets to be analyzed in the 
laboratory for losses, purity and kernel quality.  
C.1.2  The minimum amount of samples to be taken shall be twice as much as what is needed for a 
particular  analysis.  
C.1.3  The excess sample shall be used for reference purposes or for an eventual second check in case of 
review. The sampling procedures shall be undertaken at the following sheller outlets:  
a) main  kernel outlet – Using a plastic bag or an appropriate container, collect three or more samples of 
approximately 0.5 kg each from the outlet.  
b) maize -cob outlet – In the collection of sample in this outlet, use a rectangular box shaped nylon catch with 
a dim ension of 1.5 m x 1.5 m x 0.5 m open at one end of the small side. Three samples shall be collected 
from this outlet for a minimum duration of five (5) sec per collection. Separate the free maize kernel mixed 
with the cob and the kernels that are still att ached to the cob. Put them in separate containers and label 
them as separation loss and unshelled loss, respectively.  
c) fan outlet – During the test, three samples shall be taken from the fan outlet for a duration of at least 15 
sec per collection by using a  nylon net with a dimension of 1.5 m x 1.0 m held by two persons at both 
ends. These samples shall be placed in appropriate containers and labelled as blower loss.  
C.2 Collection of scattered maize kernels  
C.2.1  For testing purposes, scattered maize kernels sh all be gathered since these maize kernels are part of 
the total maize kernel input. Spread canvas sheets to the shelling floor area to catch these maize kernels after 
each trial. Placed the collected maize kernels in appropriate containers and label them a s scattered maize 
kernels.  
C.2.2  Provisions shall be provided for the collection scattered maize kernels with maximum distance of 1.0 
m away from the base of the machine.  
C.3 Handling of samples  
All samples to be taken to the laboratory shall be placed in appr opriate containers and properly labelled. If the 
samples are not to be immediately analyzed they should be air -dried and if necessary, treat samples with 
chemicals such as insecticide in order to prevent the samples from possible damage. If the sample is t o be 
used for determining moisture content, it must be kept in dry and airtight containers.  DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xvi 
 C.4 Other measurements required during the test run  
C.4.1  Data shall be taken for the following:  
a) speed of rotating components;  
b) air velocity; and  
c) noise level at the lo cation of the operators and baggers.  
C.4.2  For each data, there shall be a minimum of five observations. These shall be taken without and with 
load. Before taking data, it should be ensured that the feed rate, speed and other functional characteristics 
have stabilized. The time of sampling shall be properly space during the whole duration of the test trials. For 
air velocity, measurement shall be taken in at least six measuring points. The test engineer shall decide on the 
location of the measuring points t hat can provide him with a good estimate of the fan’s air velocity.  
C.5 Measurement of fuel consumption  
To get the amount of fuel consumed, the tank shall be filled to full capacity before the test. After the test, fill 
the tank with measured fuel to the same level before the test. When filling up the tank, careful attention shall 
be paid to keep the tank horizontal and not to leave empty space in the tank.  
 DRS 269 -2: 2020  
xvii                ©RSB2020 - All rights reserved  
 Annex  D 
(normative)  
 
Performance test data sheet  
Test Trial No:_______________________ Date: __________________ ____________  
Test Engineers:_______________________ Location: __________________________  
Test Specimen:_______________________  
Table D 1 — Items to be inspected  
Items  Trial  
1 2 3 Average  
D.1 Crop Condition      
D.1.1 Kind/Variety      
D.1.2 Days after harvest      
D.1.3 Moisture content (%)      
D.1.4 Size of ear maize      
D.1.4.1 Length (mm)      
D.1.4.2 Diameter (mm)      
D.1.5 Kernel -ear maize ratio      
D.2 Performance test      
D.2.1 Speed of components (rpm)      
D.2.1.1 Primemover      
D.2.1.1.1  Without load      
D.2.1.1.2 With load      
D.2.1.2 Shelling cylinder shaft      
D.2.1.2.1 Without load      
D.2.1.2.2 With load      
D.2.1.3 Fan shaft      
D.2.1.3.1 Without load      
D.2.1.3.2 With load      
D.2.1.4 Oscillating screen shaft      
D.2.1.4.1 Without load      
D.2.1.4.2 With load      
D.2.2 Fan air velocity (m/sec)      
D.2.2.1 Without load      DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xviii 
 D.2.2.2 With load      
D.2.3 Noise level [db(A)]      
D.2.3.1 Feeder      
D.2.3.1.1 Without load      
D.2.3.1.2 With load      
D.2.3.2 Bagger      
D.2.3.2.1 Without load      
D.2.3.2.2 With load      
D.2.4 Shelling time (min)      
D.2.5 Shelled kernel (kg)      
D.2.6 Shelling capacity (kg/h)      
D.2.7 Fuel time (min)      
D.2.8 Fuel consumed (L)      
D.2.9 Fuel consumption (L/h)      
D.3.1  Observations  
D.3.1.1  Ease of transporting the machine  
___________________________________________________________________________  
___________________________________________________________________________  
D.3.1.2  Adjustments such as belt tensions, clearan ce, air velocity and others  
___________________________________________________________________________  
___________________________________________________________________________  
D.3.1.3  Safety features  
____________________________________________________ _______________________  
___________________________________________________________________________  
D.3.1.4  Ease of cleaning the concave and cylinder  
___________________________________________________________________________  
___________________________________________________________________________  
D.3.1.5   Ease of cleaning the fan component  DRS 269 -2: 2020  
xix                ©RSB2020 - All rights reserved  
 ___________________________________________________________________________  
____________________________________________________________ _______________  
D.3.1.6   Labour requirement  
___________________________________________________________________________  
___________________________________________________________________________  
D.3.1.7   Failure or abnormalities that may be observed on th e sheller or its component parts during and 
after the shelling operation.  
___________________________________________________________________________  
___________________________________________________________________________  
D.3.18   Others  
_______________ ____________________________________________________________  
___________________________________________________________________________  DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xx 
 Annex  E 
(normative)  
 
Laboratory analysis  
E.1 Measurement of ear maize dimensions  
This shall be taken using at least ten representa tive samples of ear maize and measure the length and 
diameter.  
E.2 Measurement of kernel -ear maize ratio  
E.2.1  In measuring the kernel -ear maize ratio, take at least ten representative samples of ear maize.  
E.2.2  Take the weight of each ear maize and manually  shelled the kernels.  
E.2.3  Determine the weight of the kernel for each ear maize then compute for the kernel -ear maize ratio.  
E.3 Determination of Purity  
E.3.1  Take three 500 g samples from the main maize kernel outlet.  
E.3.2  Clean the maize kernels to remo ve the impurities and other foreign matters, the clean maize kernel 
shall be weighed and recorded.  
E.3.3  The percent purity is calculated using the formula  in Annex G.  
E.4 Determination of losses  
E.4.1  Blower loss  
E.4.1.1  Three samples shall be taken from the fan outlet to collect the maize kernels mixed with 
impurities.  
E.4.1.2  Each sample shall be cleaned and weighed.  
E.4.1.3  The total weight of the clean maize kernels and the total time of collection shall be recorded for 
the computation of blower loss (see Annex G).  
E.4.2  Separation loss  
E.4.2.1  Three samples shall be taken at the cob outlet to collect loose maize kernels mixed with the cob.  DRS 269 -2: 2020  
xxi                ©RSB2020 - All rights reserved  
 E.4.2.2  The total time of collection of the three samples shall be taken and record ed for the computation 
of separation loss (see G).  
E.4.3  Unshelled loss  
E.4.3.1  Unshelled kernels collected at the cob outlet shall be hand shelled and weighed.  
E.4.3.2  The total weight and time of collection shall be taken and recorded for the computation of 
unshelled loss (see Annex G).  
E.4.4  Scattering loss  
Kernels scattered around the sheller with a maximum distance of 1.0 m away from the base of the machine, 
shall be collected after each trial, cleaned and weighed for the determination of scattering loss. (see An nex 
G). 
E.5 Determination of net percent cracked kernels  
E.5.1  Three samples each from manually shelled and machine shelled maize kernels shall be taken for 
analysis. Each sample consists of 100 maize kernels.  
E.5.2  These maize kernels shall be inspected for the presence of fissures.  
E.5.3  The net percent cracked kernels shall be taken as the difference between the values obtained from 
the manual and machine shelled kernel samples (see Annex G).  
E.6 Determination of percent mechanically damaged kernels  
E.6.1  Three samples from machine shelled kernels shall be taken for analysis.  
E.6.2  Each sample shall consist of 100 g.  
E.6.3  Separate those kernels that were broken or crushed and weigh.  
E.6.4  Compute for the percent broken kernels (see Annex G).  DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xxii 
 Annex  F 
(normative)  
 
Laboratory grain analysis data sheet  
Machine tested: _____________________ Analyzed by: _____________________  
Date of test: _____________________ Date Analyzed:_____________________  
F.1 Crop conditions  
Table F.1 — Moisture content, (% w.b)  
Sample  
No. Initial 
weight  Final weight  Moisture 
content%  
    
    
    
Average  
 
Table F 2 — Kernel -ear maize ratio  
Sample  
No. Weight of ear Maize (g)  Weight of kernel (g)  Kernel -ear maize ratio  
1    
2    
3    
4    
5    
6    
7    
8    
9    
10    
Average     
 
 
 DRS 269 -2: 2020  
xxiii                ©RSB2020 - All rights reserved  
 F.2 Kernel -ear maize ratio  
Initial weight of samples (uncleaned) = 500 g  
Table F 3 — Purity determination  
Items  Trail 1  Trail 2  Trail 3  Gen 
Avg 1 2 3 Avg 1 2 3 Avg 1 2 3 Avg 
Cleaned (g)               
Purity (%)               
 
Table F 4 — Loss determination  
Trial No.  Blower  
loss Separation  
loss Unshelled  
loss Scattering  
loss 
Sample 
wt (g)  Total 
(Kg) Sample wt 
(g) Total 
(Kg) Sample 
wt (g)  Total 
(Kg) Sample 
wt (g)  Total 
(Kg) 
Average          
1 a         
b         
c         
Average          
2. a         
b         
c         
Average          
3. a         
b         
c         
Average          
Gen. average          
 
 
 
 
 
 
 
 
 DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xxiv 
  
Table F 5 — Shelling efficiency/recovery determination  
Trial 
No. Blower loss  Separation  
loss Unshelled  
loss Scattering  
loss Total  
Wt % wt % wt % wt % Output 
(kg) Input 
(kg) 
1           
2           
3           
Average            
 DRS 269 -2: 2020  
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 Annex  G 
(normative)  
 
Formula used during calculations and testing  
 
DRS 269-2: 2020  
©RSB 2020 - All rights reserved                  xxvi 
  
DRS 269 -2: 2020  
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DRS 269 -2: 2020  
1                ©RSB2020 - All rights reserved  
  DRS 269 -2: 2020  
 
Price based on nnn pages  
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