Hand-portable kinematic viscometer

In this paper a new microfluidic kinematic viscometer that offers effortless cleaning, simple operation, and rapid results is presented. Kinematic viscosity measurement is performed in minutes, with no calibration, no density verification, and no temperature measurement required. The unique microchannel design, in which the fluid is bound on two sides by two parallel aluminum plates, leaves the fluid exposed to air on the other two sides. This unbounded microchannel enhances the signal clarity of internal optics, but more important, it vastly simplifies cleaning. The fluid does not overflow the microchannel because there is a favorable balance of surface-tension-induced pressure over hydrostatic pressure. Kinematic viscosity is calculated based on the average velocity of the fluid front traveling down the microchannel as measured by three sets of emitters and detectors arranged along the sides of the microchannel. The results are shown to be in agreement with values obtained using commercial laboratory equipment for fluids with viscosities of less than 300 cSt measured at a constant temperature of 40°C.