The application methods of portable trace water analyzer cover multiple aspects such as operation process, maintenance, calibration and data management, as follows:
1、 Operation process
Power-on and warm-up
Connect the power cord or built-in battery to start the instrument. Some models (such as HDWS-II) require preheating for 3-10 minutes to ensure sensor stability.
Check the battery level and charge it if it is below 20% to avoid power outages halfway.
Connect sample
Gas sample: Connect SF6 equipment or other gas sources through the inlet pipe, ensuring that the joint is tightened and the outlet pipe points in a safe direction.
Liquid sample: Use an injector to draw 5-20 μ L of liquid (such as Koloa SF-T1) and slowly inject it into the titration cell, avoiding contact with the cell wall.
Parameter Settings
Flow regulation: Open the needle valve and adjust the flow rate to 0.5-0.6L/min (gas sample).
Mixing speed: Set the electrolyte mixing speed to 3-5 levels to avoid the formation of bubbles.
Measurement mode: Select Karl Fischer Coulomb method (default) or capacitance method, and adjust the endpoint judgment threshold (such as 10-50 μ A) according to the sample characteristics.
Start measurement
After automatic calibration of the instrument, real-time display of dew point value, volume ratio (ppmV), and measurement curve.
Gas sample measurement time: 5-10 minutes for the first device, 3-5 minutes for subsequent devices; The measurement time for liquid samples is about 1 minute.
Data saving and reading
Save data through touch screen or buttons (such as HDWS-II storing up to 100 records), and support querying historical records by number or time.
Some models (such as HDWS-SF6) support RS232/USB interface, which can synchronize data to computer-generated reports.
2、 Maintenance and upkeep
Daily cleaning
Immediately clean the titration cell and electrode after measurement: rinse 3-5 times with deionized water, disinfect with anhydrous ethanol, and finally blow dry with nitrogen.
The electrode needs to be soaked in a specialized cleaning solution for 5-10 minutes to remove adsorbed impurities.
Reagent management
Use Karl Fischer reagent that matches the characteristics of the sample to avoid mixing.
Reagents need to be stored at 6-8 ℃ and replaced immediately if precipitation or discoloration occurs.
Dispose of waste reagents according to environmental protection requirements, and store unused reagents in a sealed and cool place.
environmental control
Place on a sturdy tabletop, away from sources of vibration such as centrifuges.
Working temperature: 5-40 ℃, humidity ≤ 85% RH, good ventilation.
3、 Calibration and Calibration
zero point calibration
Replace the sample with high-purity nitrogen gas (pressure reducing valve pressure 0.5 bar) and observe the deviation between the test results and the zero point.
If the deviation is small, it is normal. If the deviation is large, the probe needs to be replaced or returned to the factory for calibration.
Range calibration
Inject standard samples (such as 0.1 μ L pure water), and the instrument automatically calculates the calibration coefficient.
Repeat calibration 2-3 times with an error within ± 3 μ g before sample measurement can be performed.
Sensor return to factory calibration
Some models (such as GE trace water analyzer) of probes need to be regularly returned to the factory for calibration, and users cannot operate them on their own.
4、 Data Management and Application
real-time monitoring
The LCD screen displays dew point, volume ratio, ambient temperature and humidity, and battery level, and supports dynamic curve analysis.
In industrial scenarios, 4-20mA output can be set to represent humidity, dew point, or temperature signals.
fault diagnosis
The instrument automatically detects electrode open/short circuits and electrolyte status (such as over iodine/over water).
Common problem handling:
Output at full range: Check if the sample temperature exceeds 50 ℃ and if the circuit is open.
Display value is zero: Check if the flow rate, pressure, and temperature are normal, and if the probe is at full range.
Long term storage
After shutting down, store in a dust cover and keep dry and ventilated.
When not in use for a long time, turn on the power every 1-2 months to prevent moisture damage.