A portable instrument with disposable cells for in-situ measurements of viscosity in liquids

Abstract

Viscosity is a very important property of liquids and its measure is mandatory for quality analysis in different industrial fields, such as food, paints, petroleum based products and cosmetics. Different types of viscometers exist that can measure fluids’ viscosity with high accuracy exploiting different physical principles, however these instruments are generally laboratory based and not suitable for quick in-situ measurements by untrained personnel.
In this paper a portable instrument for in-situ measurement of liquids’ viscosity is presented. The instrument is based on the falling ball principle and features a battery operated electronic board, an LCD display and a disposable cell for measurements on samples for which cleaning would be difficult and time consuming.
The instrument has been successfully tested by measuring the viscosity of tap water in the temperature range 15° - 45 °C and the viscosity of metalworking fluids in order to estimate oil concentration.