| 摘要 |
The invention relates to a method for measuring the level of a liquid in a receptacle, whereby at least one sensor (3) is arranged inside the receptacle (1). The sensor (3) is provided in the form of an optical waveguide with an air cell (22) located between both electrodes (21, 24) in which a certain quantity of the liquid (2) flows according to the level of liquid. The volumetric quantity or the level in the receptacle (1) can be determined by determining the capacitance or the change thereof as a function of the immersed sensor (3). As an evaluation method, either a change in capacity is measured or the sensor (3) is subjected to the action of a high-frequency signal and wave properties are used for determining the fluid. For example, the resonance frequency, the standing wave ratio, the frequency of a standing wave, which is generated in a defined manner, between the liquid and the feeding point, the impedance or another electrical property can all be utilized for measuring. According to the shape of the tank, a number of sensors (3) can also be arranged inside the receptacle (1) and they can be evaluated individually or by connecting them in parallel. A special embodiment incorporates the use of a special delay waveguide and operates using an electrical pulse-echo method. |
