The operation description in the HZZL-3 manual is very concise, and in fact, there are noteworthy details in each link. Organizing the complete operation process and comparing it can avoid most common mistakes.

Step 1: Horizontal calibration

Before starting up, adjust the three adjustable pins at the bottom of the instrument and observe the horizontal bubble - keeping the bubble in the middle position. The level of the instrument is the basis for the measurement accuracy of the platinum ring method. Tilting can cause the platinum ring to not be in horizontal contact with the liquid surface, resulting in asymmetric liquid film shape and lower measurement results.

Every time the instrument is moved, it must be leveled again, and it cannot be assumed that 'just placing it is enough'.

Step 2: Parameter Setting

Power on and enter the main interface, select "Parameter Settings", and enter the following in sequence:

Heavy liquid density: Lower liquid density (g/mL) - the density of input water when measuring interfacial tension (approximately 0.997g/mL), and the same lower liquid density is used when measuring surface tension

Light liquid density: When measuring surface tension, input air density (about 0.00129 g/mL); When measuring interfacial tension, input the density of the upper layer liquid (such as insulating oil)

Platinum wire radius and platinum ring radius: directly use the values on the random calibration card, do not measure them yourself instead

Current temperature: Enter the actual room temperature, and the instrument will automatically calculate the correction factor

Step 3: Weight calibration (after first use or movement)

Enter the "Weight Calibration" interface: first remove the platinum ring, wait for the reading to stabilize, and then press "Reset"; Hang the randomly attached 2g hook shaped weight on the platinum ring crossbeam, wait for the reading to stabilize, and then press "calibrate" to complete the full-scale calibration.

Step 4: Pure water calibration (validated before each use)

Select "Pure Water Calibration", place the test cup containing fresh distilled water on the test bench, press "Start", and the instrument will automatically lift the test bench. Immerse the platinum ring 5mm below the liquid level, and after a delay of 30 seconds, it will slowly descend automatically. Record the tension value when the liquid film ruptures. The surface tension of pure water at 25 ℃ should be between 71-72mN/m. If the deviation exceeds ± 1mN/m, the platinum ring cleaning status and parameter settings need to be rechecked.

Step 5: Sample measurement (interfacial tension)

Select "Sample Measurement", adjust the height of the test bench, place it in a test cup filled with distilled water, press "Start" - the instrument automatically lifts, immerses the ring, and prompts the addition of the upper layer liquid (slowly adding the tested insulating oil at this time), press "Continue", the instrument waits for 30 seconds (to stabilize the interface according to the national standard), and then automatically lowers the measurement. When the liquid film ruptures, the interfacial tension value is displayed. Press' Print 'to print out the paper, and' Exit 'to return to the main interface.