Description
Zahn Cup # 2
Using the Zahn Cup
A Zahn cup is a viscosity measurement device originally developed for use in the paint industry. It is a stainless steel cup with a tiny hole drilled in the center of the bottom of the cup. There is also a long handle attached to the sides. There are five cup specifications, labeled Zahn cup #x, where x is the number from one through five. Use large number cup sizes when viscosity is high, use low number cup sizes when viscosity is low. To determine the viscosity of a liquid, the cup is dipped and completely filled with the substance. After lifting the cup out of the substance the user measures the time until the liquid streaming out of it first stops flowing. This is the corresponding “efflux time”. A conversion table relating efflux time in seconds (to the nearest tenth of a second) to viscosity in centistokes (the viscosity unit of measurement) is furnished with each Zahn Cup.