LS/T 6103-2010 PDF English
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Inspection of grain and oils. Determination of moisture content of grain. Waterlogged suspend method
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LS/T 6103-2010: PDF in English (LST 6103-2010) LS/T 6103-2010
LS
GRAIN INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 67.060
B 20
Case No.: 29842-2010
Inspection of Grain and Oils - Determination of Moisture
Content of Grain - Waterlogged Suspend Method
ISSUED ON: OCTOBER 20, 2010
IMPLEMENTED ON: DECEMBER 1, 2010
Issued by: State Administration of Grain
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 4
5 Instruments and Equipment ... 5
6 Operation Method ... 5
7 Repeatability ... 8
Appendix A (informative) Schematic Diagram of Instrument Structure and Master
Drawings of Main Components ... 9
Inspection of Grain and Oils - Determination of Moisture
Content of Grain - Waterlogged Suspend Method
1 Scope
This Standard specifies the principle, instruments and equipment, operation method and
repeatability requirements of the determination of moisture content of grain with the
waterlogged suspend method.
This Standard is applicable to the quick determination of grain moisture, especially to the
determination of moisture in high-moisture and frozen grains.
2 Normative References
The clauses of the following documents become clauses of this Standard through the normative
references in this Standard. In terms of references with a specified date, all subsequent
amendments (excluding errata content) or revisions do not apply to this Standard. However, the
various parties that reach an agreement in accordance with this Standard are encouraged to
explore whether the latest versions of these documents are applicable. In terms of references
without a date, the latest versions apply to this Standard.
GB 5491 Inspection of Grain and Oilseeds - Methods for Sampling and Sample Reduction
LS/T 3705 Technical Requirements and Test Method for Quick Moisture Content Tester of
Waterlogged Suspend
3 Terms and Definitions
The following terms and definitions are applicable to this document.
3.1 waterlogging suspend method
Waterlogging suspend method refers to the method, in which, the object to be determined is
completely immersed in water and suspended for weighing.
4 Principle
Weigh-take a certain amount of pulverized specimen into a constant-mass measuring vessel, fill
it with water to fully infiltrate the sample; completely immerse an airtight measuring vessel in
water, and weigh its mass. In accordance with the principle of buoyancy method, the obtained
mass is the dry matter of the sample and the mass of the measuring vessel, and the moisture
content of the specimen can be obtained through calculation.
5 Instruments and Equipment
5.1 Quick Moisture Content Tester of Waterlogged Suspend
The schematic diagram of the instrument structure and the master drawings of the main
components are shown in Appendix A. The instrument shall comply with the requirements of
LS/T 3705 and be accompanied by the following parts:
5.1.1 Water tanks: hold clear water (the water quality is clean fresh water), and the water quality
and temperature in each tank shall remain consistent.
---Operating tank: used for soaking the measuring vessel and water filling, etc. A
transparent plastic tank with a length of 240 mm, a width of 170 mm and a height of
150 mm.
---Weighing tank: used for the suspended weighing of the measuring vessel. A transparent
plastic tank with a diameter of 130 mm and a height of 150 mm.
5.1.2 Measuring vessel: an aluminum alloy container with a loading inlet (with a diameter of
21 mm) at the top and a water injection port with a one-way valve, equipped with a sealing
cover for the loading inlet, an inner diameter of 32 mm, an inner height of 45 mm and a wall
thickness of 2 mm.
5.1.3 Sample weighing dish: open on one side, and capable of holding about 10 g of specimen.
5.1.4 Stirring rod: made of stainless steel, with a diameter of 2 mm and a length of about 85
mm.
5.1.5 Water injector: 20 mL medical syringe.
5.1.6 Mortar: capable of holding about 100 g of sample.
5.2 Hammer-type Electric Pulverizer
Attached with round-hole sieves with diameters of 1.5 mm and 2.5 mm. During operation, the
temperature of the pulverizer shall not be greater than 25 C.
6 Operation Method
6.1 Instrument Preparation
In accordance with the instruction manual of the moisture content tester, prepare the instrument.
Place the moisture content tester (5.1) on a stable operating table, and fill the two water tanks
(5.1.1) with clean water (the water surface reaches the water level). Put the measuring vessel
(5.1.2) and the sealing cover of the measuring vessel into the operating water tank for soaking;
put the weighing water tank under the lower scale hook of the moisture content tester (see
Figure A.1 of Appendix A).
Use the water injection hose to inject clean water with the same temperature as the water in the
water tank into the water storage tank of the moisture content tester; observe the water level
mark, make the water level reach the marked line, then, remove the water injection hose.
Adjust the weighing device to horizontal and turn on the power. Use the standard weight
provided with the instrument and in accordance with the instruction manual of the instrument,
calibrate the weighing device. In accordance with the type of the sample to be tested, select the
measurement mode of the corresponding grain type on the operation panel of the host machine.
If the moisture content tester is not used for a long time or continuously used for more than 100
times, it shall be calibrated in accordance with LS/T 3705.
6.2 Constant-mass Measuring vessel
6.2.1 Use the water injection suppression clamp to clamp the water injection port of the soaked
measuring vessel, press the “water filling” key on the instrument panel to suppress once, so as
to discharge the air in the water injection port of the measuring vessel.
6.2.2 In the operating tank, fill the measuring vessel with clean water (there shall be no air
bubbles), then, use a sealing cover to properly seal the measuring vessel. Use the water injection
pressure clamp to clamp the water injection port of the measuring vessel, press the “water filling”
key on the instrument panel to suppress once.
6.2.3 Loosen the water injection suppression clamp, remove the measuring vessel, hang the
water-filled measuring vessel on the lower scale hook at the bottom of the weighing device,
suspend it in the weighing tank for weighing; record the stable weighing data displayed by the
weighing device. Repeat the operation of 6.2.1 ~ 6.2.3, until the mass difference between the
two weighing before and after is not greater than 3 mg, i.e., the constant mass is achieved. Store
a larger data in the constant-mass measuring vessel interference of the moisture content tester
as the constant-mass data (refer to the instruction manual of the moisture content tester) and
record it as m1.
6.2.4 During the determination, the difference between the water temperature and the ambient
temperature of the laboratory shall not exceed 3 C. When the difference between the ambient
temperature and the water temperature exceeds 3 C, operate in accordance with 6.2.1 ~ 6.2.3
again.
6.3 Specimen Preparation
6.3.1 Sampling and sample reduction
Comply with GB 5491.
6.4.5 On the instrument determination interface, if the estimated moisture content of the sample
is not greater than 19%, select the “dry sample mode” for weighing; if the estimated moisture
content of the sample is greater than 19%, select the “wet sample mode” for weighing.
6.4.6 Loosen the water injection suppression clamp, remove the measuring vessel, hang the
measuring vessel on the lower scale hook at the bottom of the weighing device, suspend it in
the weighing tank for weighing. After the displayed weighing indication becomes stable, store
the data in the column of determination value on the determination interface (refer to the
instruction manual of the moisture content tester) and record it as m2.
6.4.7 In accordance with the determination result, if the moisture content of the sample is
consistent with the estimated content before the sample is pulverized (if the determination result
is that the estimated moisture content is greater than 19%, 0.5 percentage points shall be
subtracted), then, the determination result is valid; otherwise, in accordance with 6.3.2 ~ 6.4.6,
re-operate it, and pay attention to select the correct sample pulverization mode and
determination mode (i.e., dry sample mode or wet sample mode).
6.5 Result Calculation
The moisture content tester automatically calculates the moisture content determination result
in accordance with the weighing data m, m1 and m2, displays the moisture content of the sample
being tested. Or the determination results can also be printed out and output by a printer, and
the determination data can be saved. In accordance with Formula (1), calculate:
Where,
X---the moisture content (mass fraction) of the sample;
m---the sample mass, expressed in (g);
m1---the mass of the water injection measuring vessel in water, expressed in (g);
m2---the mass of the water injection measuring vessel and the dry matter of the sample in water,
expressed in (g);
k---the conversion coefficient (2.8 for corn and wheat; 2.7 for unhusked rice and other grain
varieties).
7 Repeatability
Under repeatability conditions, the same sample shall be subject to parallel determination twice,
and the absolute difference between the two determination results shall not be greater than 0.2%.
Take the arithmetic mean of the two determination results as the moisture content of the
specimen.
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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