Most popular on the market today is the Zahn cup, which is widely used in the paint industry. It is a portable device for quickly checking the viscosity of liquids. There are five cup specifications, with different opening sizes ranging from 5 to 1840cSt. Large number cup sizes are used when viscosity is high, while low number cup sizes are used when viscosity is low. Zahan viscosity cup is also known as dip-type viscosity cup because of the manner in which viscosity of a test sample is determined. Simply dip the cup into the product to be measured, lift it out and measure how long it takes for the contents to empty through the opening.See more.
The viscosity of fluids is a measurement of the resistance to deformation by stress. For most liquids it represents the concept of “thickness”, as an example ketchup has a much higher viscosity than water. Viscosity is the collision between particles in a fluid which are at different velocities.
When a fluid is forced in a tube, the particles of the fluid move more quickly at the tubes axis and more slowly near the walls of the tube; therefore stress is needed to overcome friction between each particle layer in order to help keep the fluid moving along.
A popular Viscosity tester is the ‘ford viscosity cup’ which is a simple gravity device this allows the timed flow of a known volume of liquid to pass through a hole at the bottom. However, the conditions when using a viscosity cup are very important, and a drop in temperature will effect results, therefore getting consistent results ideally can be achieved from a controlled environment.
Another popular viscosity tester we sell at Ascott is the Zahn cup, which is mainly used by the paint industry as a measurement device. The Zahn cup is commonly made from stainless steel with a small hole drilled in the bottom of the cup. You can buy the Zahn cup in various different sizes which allows for lower viscosity fluids.
To find out the viscosity of a liquid using the Zahn cup, you would dip the cup completely in the substance filling the cup up. Once you have lifted the Zahn cup out of the substance, you will need to measure the time it takes for the liquid streaming out to break up, this is known as the “efflux time”.
At Ascott we stock a variety of different viscosity instruments including viscosity cups, beakers and stands.