| 摘要 |
<p>The invention relates to a method and an apparatus for measuring and studying the surface tension of liquids in various conditions of temperature and chemical or bio-chemical kinetics. According to the invention, the method is based on the principle of measuring the maximum force (F) of stripping the circular surface of a piezoelectric oscillator off the surface of the studied liquid, for this purpose using the value of the frequency deviation (δf) from the resonance frequency (f) of the mentioned piezoelectric oscillator. As claimed by the invention, the apparatus consists of a laboratory structure which comprises a measuring unit (A) and an electronic unit (B), where the measuring unit (A) consists of a rigid frame (1), whereon there is mounted a positioning system, consisting, in its turn, of an actuation button (2), a toothed pinion (3), a rack column (4), a blocking screw (5), a cross body (6), as well as a tank (7) comprising the studied liquid (8), a Peltier-type thermostat jacket (9), a temperature sensor (10), as well as an electromechanical moving system consisting of a direct current electro-motor (11) equipped with an incremental rotary photoelectric sensor (12), a speed reducer (13), a system for transforming the motion of screw (14) - mobile nut (15)-type, and some interchangeable rods (18, 19, 20, 21), provided, at the lower part, with some piezoelectric oscillators (22, 23, 24, 25) of various diameters, but having the same thickness, which are fixed and clamped with a nut (17) knurled on the mobile nut (15), and the electronic unit (B) comprises an electronic oscillator, a phase and frequency comparator, a displacement measuring system, a system for assigning, measuring and controlling the speed of the electric motor (11) and a microprocessor for providing the measuring process.</p> |
