Grain analyzer is a key equipment used to detect grain quality, and its usage details directly affect the detection accuracy and instrument life. The following provides a detailed explanation from six aspects: operational procedures, parameter settings, environmental control, sample processing, data interpretation, and maintenance.

1、 Preparation before operation

1. Instrument self inspection and calibration

-Preheat for 15-30 minutes after turning on (different models require different requirements) to ensure the stability of sensors and circuits.

-Calibration standard parameters: Use standard weights or grain samples with known parameters (such as rice with a moisture content of 20%) for calibration, with an error controlled within ± 0.5%.

-Check whether the light source system (near-infrared or laser light source) is clean and avoid dust affecting the optical detection accuracy.

2. Sample pretreatment

-Cleanliness: To remove impurities (such as sediment and debris) from grains, it is recommended to use a sieve (with a pore size of 1-2mm) for filtration.

-Crushing rate control: If it is necessary to crush the sample (such as measuring starch content), it needs to pass through a 60-80 mesh sieve after crushing to avoid uneven particle size and result deviation.

-Temperature and humidity balance: The sample should be placed at room temperature (25 ℃± 2 ℃) for more than 2 hours to avoid moisture condensation and interference with detection due to temperature differences.

2、 Core operational steps

1. Sample weighing and installation

-The sample size should be strictly measured according to the instrument requirements (usually 10-50g). Too much may squeeze and affect the sensor, while too little may result in insufficient signal.

-When loading the sample, it should be evenly spread to avoid stacking and tilting, especially when using bulk density measurement, it is necessary to ensure that the grain is naturally dense.

2. Parameter settings

-Selection of detection mode: Select detection items according to needs (such as moisture, protein, fat, particle size distribution, etc.), and some instruments support multi parameter synchronous detection.

-Threshold adjustment: For example, near-infrared spectroscopy analysis requires setting an absorbance threshold to avoid background noise interference; The laser particle size analyzer needs to set the range of scattered light receiving angles.

3. Monitoring of the detection process

-Real time observation of data fluctuations: If the values fluctuate violently, it may be due to uneven sample loading or sensor failure.

-Avoid vibration interference: Do not touch the instrument or move the table during the detection process, and keep the magnetic stirrer running at low speed (if necessary).

3、 Key points of environmental control

1. Temperature and humidity

-The fluctuation of environmental temperature should be controlled within ± 1 ℃. High temperature may cause the electronic components of the instrument to overheat, while low temperature may affect the sensitivity of the sensor.

-Excessive humidity (>70%) can easily cause moisture absorption in grains. It is recommended to test or activate the dehumidification function of the instrument in a drying oven (humidity ≤ 40%).

2. Avoid light and dust

-The optical detection module should avoid direct sunlight and use a light shield; Regularly clean the lens and wipe it with lens cleaning paper.

-The sample chamber needs to be well sealed to prevent dust from entering and affecting the optical path or blocking the gas path system.

4、 Data interpretation and exception handling

1. Result verification

-Perform parallel testing at least 3 times, calculate the average, and eliminate outliers with deviations exceeding ± 2%.

-Comparison with industry standards: For example, the normal range of wheat moisture content is 12% -14%. If the result exceeds this range, it is necessary to check whether the calibration is invalid.

2. Common abnormal troubleshooting

-Data drift: Check if the sensor connection wire is loose, or recalibrate the zero point.

-Poor repeatability: It may be due to uneven mixing of the sample, requiring resampling and thorough mixing.

-Low value: Due to aging of the light source (such as insufficient energy of near-infrared lamps) or decreased sensitivity of the detector, replacement of accessories is required.

5、 Maintenance and upkeep

1. Daily maintenance

-Clean the sample residue after each test, and use a soft bristled brush to clean the testing chamber and conveyor belt.

-Check the sensor window monthly and gently wipe it with a dust-free cloth dipped in alcohol (concentration<70%).

2. Periodic calibration

-Use standard substances to calibrate instruments every quarter and record calibration logs.

-Every year, professional organizations conduct metrological certification to ensure compliance with national standards (such as GB/T 24499-2009).

3. Long term storage management

-Clean and place desiccants before shutting down, and cover with a dust cover.

-When not in use for a long time, disconnect the power supply and preheat the components for 1 hour every month to prevent them from getting damp.

6、 Special scenario precautions

1. Detection of high oil content samples (such as soybeans and corn)

-It is necessary to add a solvent cleaning step to avoid contamination of the sensor by grease adhesion.

-Priority should be given to selecting specialized modes (such as "high-fat detection"), and some instruments require manual input of fat correction factors.

2. Testing of aged grains

-The decrease in enzyme activity in aged grains may lead to delayed detection results. It is recommended to extend the detection time or increase the light source intensity.