Abstract: A liquid detector utilizing fiber optics, by which the presence of oils and various solvents can be detected. The detector is internally safe because the optical fiber is an insulator and may therefore be used to monitor liquids involving fire or explosive hazards. The detector may be used to detect leakage when storing oils and solvents, because it reacts most rapidly with these liquids. The detector makes use of capillarity of a sensing pick-up thereof, the optical reflection coefficient of the pick-up material changing as the pick-up material comes into contact with the liquid to be detected.

Abstract: The object of the present invention is to measure the magnitude of the friction and coefficient of friction or liquids with high viscosity or internal friction, such as molten plastic mix, e.g. in extruders by increasing the velocity of flow in a special measuring sleeve by stepwise reducing the flow cross section, whereby the flow velocity increases stepwise in accordance with the laws of hydrodynamics. When flow thermometers are installed at the points of reduction, the increase of friction energy can be assessed by the increase of temperature. When the temperature changes can be measured, the quantities describing the friction are calculable. The meter is applicable in numerous different situation and types of apparatus in which measurement of the friction energy is desired.