How to Measure Viscosity | Flow Cups | Elcometer USA

In this article we will cover how to conduct a simple and accurate viscosity test with the flow cup. Viscosity measurements are important when checking a products quality and efficiency. The Viscosity of a material is the measurement of its flow. This flow helps determine the proper consistency and can verify product quality. Viscosity tests are used in a variety of industries such as food in order to calculate the right consistency and the painting industry to verify that the product will operate correctly in machinery.

Determine The Proper Flow Cup

First check the products technical data sheet to see if a flow cup has been listed. If not listed, select a cup that will give an estimated flow time of 30 - 100 seconds. Validate there are no pre-set standards since certain viscosity tests have unique flow time standards.

Clean Measuring Device

Using a suitable solvent clean the cup, handle and orifice to verify there is no residue. Dirty equipment will impact the accuracy of the test. Using abrasive cleaning materials such as a wire brush could damage the cup again causing issues in accuracy.

Place the Cup

Place the flow cup into its stand and ensure that it is level. To ensure that everything is level put glass and a bubble level on top of the cup. Then adjust the feet until a level measurement has been achieved.

Measure the Viscosity

Verify that the cup temperature and the liquids temperature are uniform before testing. Then verify the substance has no air bubbles in it (ideally freshly strained). Once verified complete the following:

1. Cover the hole at the bottom of your flow cup with your finger.
2. Slightly over-fill the flow cup with your material.
3. Slide the glass plate over the liquid, removing any excess from when it was filled. Try avoiding any air bubbles.
4. Remove your finger from the cup and place a beaker under it. Grab your stop watch.
5. Slowly remove the glass and as soon as you do start the stop watch. When the materials flow breaks stop the watch.

Calculate the Viscosity

To calculate the viscosity into cST you will need the following data:

• Time (seconds)
• K and c Constants (provided by cup)

ElcoCalc Calculation

1. Download ElcoCalc App on Android or Apple
2. Open app and enter in the cup used and time
3. cST is instantly provided by the App

Traditional Calculation

1. Write down the following formula: K(t-c) = V
2. Find the cups constants in the provided tables
3. Set "t" equal to the flow time, set "K" and "c" equal to the constants
4. Calculate for "V" and you have your viscosity