Autori: Spanu, A., Hadar, A., Dragoi, G

Editorial: Mat. Plast., 43 (3), p.199-203, 2006.

Rezumat:

In order to test the presence of some chemical substances within the composition of specific liquids and fluids, such as cosmetics, beverages, hydraulic oil, it is absolutely necessary to measure the foam level as a quality condition for selling them on the market. The paper deals with designing an original device for measuring the foam level, which has the following main components: a mechanical subassembly for positioning the sensors, a closed volume with a propeller subassembly for mixing the liquid and the PC controller. We recommend the use of Thermo-Russel sensors, taking into account the accuracy of the final results. Electrical micro actuators, such as brushless electrical micromotors, are used for actuating the mechanical components. The designed device may have the following original features: the electro-mechanical positioning system for sensors and propeller in the way regarding the increasing of the positioning accuracy of the sensors; the possibility of having different rotational speed of the propeller, as function of liquid viscosity. Taking into account that the foam level could be rapidly destroyed, so that the process time should be over 0.1 s, the device might be controlled either by microcontrollers or by a PC with data acquisition boards. Knowing that the creep of the propeller is altering the measuring final results by reducing the speed of the liquid, the paper presents the tridimensional model of the propeller and its translational displacements using the finite elemet method.

Cuvinte cheie: modelling simulation, generating wet foam into liquids, measurement