The calibration of a high flow laser dust particle counter needs to follow a rigorous process to ensure the accuracy and reliability of the detection data. Based on the characteristics of the KQ-4011 high flow 28.3L desktop laser dust particle counter, the specific calibration process is as follows:
1. Preparation before calibration: Firstly, select a qualified calibration institution, such as an instrument manufacturer or a third-party metrology institution recognized by the National Accreditation Service (CNAS). Calibration personnel need to check whether the appearance of the counter is damaged, confirm the instrument model, number and other information, and prepare the standard particle generator, flow calibration device, temperature and humidity meter and other equipment required for calibration. At the same time, ensure that the temperature, humidity, cleanliness and other conditions of the calibration environment meet the instrument calibration requirements. Generally, the temperature is controlled between 20 ℃ -25 ℃, the relative humidity is between 40% -60%, and it is carried out in a clean room to prevent external particles from interfering with the calibration results.
2. Appearance and functional inspection: Carefully inspect the all 304 stainless steel body of KQ-4011 for scratches and deformation, check if the 7-inch high-definition large screen display is normal, whether the touch screen operation is sensitive, and whether each function button can respond normally. Turn on the instrument and check the data storage and export functions, such as 20000 sets of large capacity data storage and one click export of PDF files from a USB drive, to ensure smooth operation of the human-computer interaction interface. The functions of 400 room point presets and 20 user management run smoothly.
3. Flow calibration: Use a high-precision flow calibration device and connect it to the sampling inlet of KQ-4011. KQ-4011 has a high flow sampling function of 28.3L. Set the instrument to run at different flow levels, read and record the flow values displayed by the instrument. Comparing the standard flow rate value with the instrument display value, if the deviation exceeds the allowable range of ± 5% (taking KQ-4011 as an example), the flow rate is calibrated using the instrument's built-in flow adjustment function and a real-time flow self adjustment system implemented by flow sensors and intelligent algorithms until the error between the instrument display flow rate and the standard flow rate is within the specified range.
4. Particle size detection calibration: Use a standard particle generator to generate standard particles with known particle sizes and concentrations, such as 0.1um, 0.5um, 5um, and other different particle size ranges (KQ-4011 can detect up to 0.1um). Introducing standard particles into the detection area of the counter, KQ-4011 counts particles based on the principle of light scattering and photoelectric sensing technology. Record the counting results of standard particles with different particle sizes by the instrument, and compare them with the actual concentration and particle size of the standard particles. If the particle size distribution error exceeds ± 20%, or the concentration indication error exceeds ± 20% FS at a particle size of 0.5 μ m (taking KQ-4011 technical parameters as an example), the optical detection system and signal processing system of the instrument need to be adjusted and calibrated to ensure accurate detection of particles of various sizes.
5. Laser source calibration: KQ-4011 is equipped with a 10-year imported semiconductor laser diode, which is the core component for testing. Using a professional optical power meter to measure the output power of a laser diode, if the power drops beyond the specified range or the laser wavelength shifts, it will affect the sensitivity and accuracy of particle detection. At this time, the laser diode needs to be calibrated or adjusted, and if necessary, replaced according to the manufacturer's requirements (calibrated annually). After calibration, the performance of the laser light source should be verified again to ensure its stability and reliability.
6. Data accuracy verification: After completing the above calibration steps, conduct a comprehensive test on the instrument again. Using standard particle samples with different concentrations and particle size distributions, simulate actual detection scenarios, and perform multiple repeated tests on KQ-4011 to check whether its relative error of repeatability is less than ± 5% (taking KQ-4011 as an example). At the same time, verify whether the audit trail, log management, and other functions are recording the calibration process and results properly, ensuring the integrity and traceability of data, and complying with the FDA 21CFR PART11 specification requirements.
7. Issue calibration certificate: After the calibration is completed and all indicators meet the requirements, the calibration institution will issue a detailed calibration certificate, indicating the calibration basis, calibration items, calibration results, calibration date and other information, confirming that the instrument meets the calibration standards in its current state and can continue to be used. Users should keep the calibration certificate properly as an important proof of instrument measurement qualification.