Devansh Gupta presents on measuring cup viscosity. A Zahn cup is a stainless steel cup with a small hole in the bottom used to measure the viscosity of liquids in industries like paint, rubber, petrochemicals and more. There are five numbered Zahn cups where higher numbers are used for more viscous liquids. To determine viscosity, the proper cup is selected based on liquid density and immersed in the sample. The time for the liquid to drain completely through the hole is measured and used to calculate viscosity.

1. Measurement of Cup
Viscosity
Presented by
Devansh Gupta
M.Sc Polymer Science
Semester 2

2. • Viscosity is a measure of the resistance of a fluid which is
being deformed by either shear stress or tensile stress.
• A Zahn cup is a device which is used in a paint industry,
In paint industry, rubber industry, petrochemical
industry, cosmetics, Sugar mills & dairy to measure
viscosity of liquids.
• Generally it is a stainless steel cup with a tiny hole drilled
in the center of the bottom of the cup. A handle is also
attached on the sides of the cup.
• There are five types of cups are available labled as Zahn
cup #X, where X is the number from one to five, when the
viscosity is high the cup with large X will be used and
when the viscosity is low the cup with low X will be used.
Introduction

3. How To Determine Cup Viscosity?
• To determine the viscosity of a liquid by this method, first according to the
density the appropriate cup is taken.
• After selecting the proper cup Immerse the cup and a thermometer in the
sample container and stir the sample well to ensure uniform temperature and
density. Allow the cup to remain in the fluid for at least 5 minutes to allow
the cup temperature to stabilize, record the temperature.
• Now, lift the cup out of the container and hold it vertically.
• As the liquid in the cup starts to come out, start the timer.
• Measure the time until the whole liquid comes out through the tiny hole in
the bottom, generally the time for the cup to empty should be between 20 and
80 seconds.
• Following each determination, clean the cup with a suitable solvent and a soft
cloth or soft brush.
• Record the all the data, which can be used in some equation to calculate the
viscosity of the liquid.

4. That’s All