GB/T 6499-2022 English PDF (GBT6499-2022)

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GB/T 6499-2022: Test method for percentage of trash content in raw cotton
GB/T 6499-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.060.10
CCS B 32
GB/T 6499-2022
Replacing GB/T 6499-2012
Test method for percentage of trash content in raw cotton
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: MAY 01, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Sampling of batch sample and laboratory sample ... 6
5 Test methods ... 6
6 Precision ... 9
7 Test report ... 9
Annex A (informative) Precision of test methods ... 11
Annex B (informative) Test report sheet of percentage of trash content in raw cotton
... 12
Bibliography ... 13
Test method for percentage of trash content in raw cotton
1 Scope
This document specifies the test method for determining the percentage of trash content
in raw cotton using raw cotton trash analyzer (method A) and fully automatic raw cotton
trash analysis system (method B).
This document applies to raw cotton, including saw ginned cotton and roller ginned
cotton.
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.
GB 1103.1 Cotton - Part 1: Saw ginned upland cotton
GB 1103.2 Cotton - Part 2: Roller ginned upland cotton
GB/T 1103.3 Cotton - Natural color uplands cotton
GB/T 6097 Sampling method for testing of cotton fibers
GB/T 8170 Rules of rounding off for numerical values and expression and judgement
of limiting values
GB/T 19635 Cotton - Sea island cotton
GB/T 32139 Terms of cotton processing
3 Terms and definitions
For the purpose of this document, the following terms and definitions and those defined
in GB/T 32139 apply.
3.1
trash
Non-cotton fiber materials contained in raw cotton and fibers attached to these materials,
such as sand, branches and leaves, boll shells, insect feces, insect corpses, cottonseeds,
seed cotton, seed coat fragments, motes, seed-coat fragments with lint, soft seed
epidermis, etc.
3.2
percentage of trash
The percentage of the mass of trash in the raw cotton sample to the mass of the sample.
4 Sampling of batch sample and laboratory sample
The sampling of batch sample of raw cotton shall be carried out in accordance with the
provisions of GB 1103.1, GB 1103.2, GB/T 1103.3, GB/T 19635, and the sampling of
laboratory sample shall be carried out in accordance with the provisions of GB/T 6097.
The laboratory sample shall be no less than 600 g.
5 Test methods
5.1 Method A - raw cotton trash analyzer method
5.1.1 Principle
According to the principle of aerodynamics, the cotton fibers and trashes attached to
them are separated by the combined action of high-speed rotating mechanical parts and
airflow, the trashes are collected and weighed, and the percentage of trash mass to the
sample mass is calculated to obtain the percentage of trash content in raw cotton.
5.1.2 Instruments and tools
5.1.2.1 Raw cotton trash analyzer, which consists of a cotton feeding table, a cotton
feeding roller, a licker-in roller, a dust removal knife, a streamline plate, a cotton
stripping knife, a dust cage, a trash box, a fan, and a motor.
5.1.2.2 Balance: range ≥ 100 g, division value 0.01 g.
5.1.2.3 Brown brush, tweezers.
5.1.3 Sample preparation
From the laboratory sample, use the quartering method to extract two (50 ± 1) g test
samples and one (50 ± 1) g spare sample, and weigh the sample mass with a balance to
an accuracy of 0.1 g.
5.1.4 Test steps
5.1.4.1 Start the machine and run for 1 min ~ 2 min, then stop the machine to clean the
trash box, clean cotton box, cotton feeding table, and licker-in roller.
5.1.5.5 All test results shall be rounded off according to GB/T 8170.
5.2 Method B - fully automatic raw cotton trash analysis system method
5.2.1 Principle
According to the principle of aerodynamics, the sample is fed into the fully automatic
raw cotton trash analysis system; under the action of the combing roller, the sample is
loosened; under the action of the dust removal knife and streamline knife, the fibers and
trashes in the sample are separated; the fibers in the sample are attached to the surface
of the dust cage with the movement of the airflow and fall into the waste cotton box;
the trashes in the sample fall on the electronic scale tray in the trash box because of
their greater specific gravity than the fibers, and the trashes are automatically weighed;
through the automatic calculation system, the percentage of trash content in raw cotton
is obtained.
5.2.2 Instruments and reference materials
5.2.2.1 Fully automatic raw cotton trash analysis system, which consists of an efficient
trash separation and collection system, an automatic trash weighing and calculation
system, etc.
5.2.2.2 Balance: range ≥ 100 g, division value 0.01 g.
5.2.2.3 Reference material of percentage of trash content in raw cotton, GSB 11-3812.
5.2.3 Sample preparation
From the laboratory sample, use the quartering method to extract two (100 ± 10) g test
samples and one (100 ± 10) g spare sample, and weigh the sample mass with a balance
to an accuracy of 0.1 g.
5.2.4 Equipment calibration and calibration check
Select the reference material of percentage of trash content in raw cotton (GSB 11-
3812), and calibrate according to the calibration procedure of the fully automatic raw
cotton trash analysis system. If the test difference of the reference material is within the
uncertainty range of the reference material, it is determined to have passed the
calibration.
For the fully automatic raw cotton trash analysis system in use, reference materials shall
be selected regularly for calibration checks. If the test difference is within the
uncertainty range of the reference material, it is determined to have passed the
calibration check.
5.2.5 Test steps
5.2.5.1 Check and empty the waste cotton box and trash box of the instrument.
5.2.5.2 Select the instrument test procedure.
5.2.5.3 Enter the cotton sample type (saw ginned cotton or roller ginned cotton) and
sample information.
5.2.5.4 Spread the test sample evenly on the sample table or automatic cotton feeding
device.
5.2.5.5 The test instrument automatically performs steps such as combing, trash
collection, trash weighing, and result calculation on the cotton sample.
5.2.5.6 Repeat test steps 5.2.5.1 ~ 5.2.5.5 to test the second sample.
5.2.6 Calculation of test results and rounding off of numerical values
5.2.6.1 The percentage of trash content of a single sample shall be rounded off to two
decimal places according to GB/T 8170; the final percentage of trash content of sample
shall be expressed as the average value of the samples and rounded off to one decimal
place.
5.2.6.2 For saw ginned cotton with percentage of trash content less than 2.5 %, if the
difference between the two test results is greater than 0.34, test a spare sample; the final
result shall be expressed as the arithmetic mean of the three samples and rounded off to
one decimal place.
5.2.6.3 For saw ginned cotton with percentage of trash content greater than 2.5 %, if
the difference between the two test results is greater than 0.5...