Questions about Automatic Kinematic Viscosity Tester

What solution is used in the constant temperature bath of an automatic kinematic viscosity tester?

The liquid medium in the constant temperature bath depends on the test temperature:

1. Low / room temperature (≤75°C or ≤80°C)

Distilled water / deionized water

Sometimes purified water

Features: clean, good heat transfer, non-corrosive

2. Medium to high temperature (80°C–100°C)

Glycerin (glycerol)

25% ammonium nitrate aqueous solution (recommended by GB/T 265)

Silicone oil (flash point > 190°C, 10–20 mm²/s)

3. Low temperature (around 0°C or below)

Ice-water mixture

Ethanol + dry ice (for lower temperatures)

Summary:

≤75°C: water

75–100°C: glycerin / ammonium nitrate solution / silicone oil

<0°C: ice-water or ethanol system

Can it be used for gear oil testing?

Yes, it can be used. Gear oil is a standard application for kinematic viscosity testers.

Standards: GB/T 265, ASTM D445

Applications: gear oil, hydraulic oil, engine oil, transmission oil, and other lubricants

Gear oil viscosity grades (such as 100, 150, 220, 320) are defined by kinematic viscosity at 40°C and 100°C.

Key points:

Use larger-diameter capillary tubes for high-viscosity oils

Preheat and degas the sample before testing to avoid bubbles

Calibration specification of kinematic viscosity tester

The calibration follows JJF 1274—2025 “Calibration Specification for Kinematic Viscosity Tester”, applicable to instruments operating between 20°C and 100°C.

1. Key updated metrological requirements

Temperature indication error added as a key index

For integrated instruments: include constant stability

Focus on practical operational stability

2. Calibration items

Temperature system calibration

Use standard platinum resistance thermometer or secondary standard thermometer at 40°C and 100°C.

Error requirement: ≤ ±0.1°C

Viscosity system calibration

Use certified standard oil. Compare measured viscosity with reference value.

Relative error: typically ≤ 1.0%

Timing system calibration

Verify with precision stopwatch or calibrator.

Time error: ≤ ±0.1 s

3. Calibration interval

Recommended: every 6–12 months

High-frequency use or after maintenance: shorten interval or perform intermediate checks

4. Records

Calibration data, environment, standards used, and results must be recorded and retained for at least 3 years.

Price of kinematic viscosity tester

Prices vary significantly depending on configuration:

1. Basic manual / semi-automatic models

¥3,000 – ¥6,000

2. Standard automatic models

¥15,000 – ¥25,000

(automatic timing, temperature control, basic automation)

3. High-precision full automatic models

≥ ¥39,800

(±0.05°C temperature control, higher stability)

4. Research-grade / customized systems

Up to ¥100,000+

(used for polymer research and high-end laboratory analysis)

Key factors affecting price

Level of automation (manual vs fully automatic)

Temperature control accuracy (higher precision = higher cost)

Number of test channels (single vs multi-sample testing)

Sensor and component quality (imported vs standard components)

2026-04-22 15:59