LimsPulse
Petroleum testing

Kinematic Viscosity Bath

A clear, stirred liquid bath held to within about ±0.02 °C, in which calibrated glass capillary viscometers are timed. Flow time multiplied by the viscometer constant gives kinematic viscosity in mm²/s (cSt).

  • Lubricant blending
  • Petroleum refining
  • Fuel terminals
  • Marine fuel testing
  • Fleet and machinery oil condition monitoring
  • Independent testing laboratories
Illustration of Kinematic Viscosity Bath
LEARN & PRACTICE

Test your Viscosity bath knowledge

Multiple-choice questions

Pick an answer to see whether you are right and why.

  1. Q1. Kinematic viscosity is calculated as…

    basic

  2. Q2. What temperature control does ASTM D445 require between 15 and 100 °C?

    basic

  3. Q3. What is the minimum flow time in a glass capillary viscometer under D445?

    intermediate

  4. Q4. A viscometer has C = 0.0500 mm²/s² and the flow time is 640.0 s. What is ν?

    intermediate

  5. Q5. Kinematic viscosity is 42.0 mm²/s and density 0.860 g/cm³. What is the dynamic viscosity?

    intermediate

  6. Q6. Which type of viscometer is used for dark, opaque used engine oils?

    basic

  7. Q7. Two flow times from one filling differ by 0.6%. What should you do?

    advanced

Viva questions

Think of your answer first, then open it to compare.

  1. 1. Why must the viscometer hang exactly vertically?

    Tilting changes the effective height of the liquid column (the driving head) and the path of flow, which changes the flow time. Holders are designed to keep viscometers vertical.

  2. 2. How do you verify a viscometer constant?

    Measure the flow time of a certified viscosity standard at the certified temperature, divide the certified viscosity by the mean flow time to get C, and compare with the certified constant. Deposits, damage or wrong temperature can make it differ.

  3. 3. What is the difference between kinematic and dynamic viscosity?

    Dynamic viscosity (mPa·s) is resistance to flow under an applied force. Kinematic viscosity (mm²/s) is dynamic viscosity divided by density; it is what a gravity-driven capillary viscometer measures.

In LimsPulse · Calibration Management

Keep every Viscosity bath in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how