The invention relates to an apparatus and a method for determining the filling level of a liquid in a container (4). The apparatus comprises at least one element (1, 2) which transmits and/or receives acoustic signals. The acoustic signals propagate along a surface of a solid (3). The solid (3) is arranged in such a manner that at least one part of a surface of the solid (3) can be wetted by the liquid. The solid (3) has, at different container heights, regions (5) which reflect the acoustic signals.

Liquid level detection using acoustic surface waves

Filling level measurement

The invention relates to a method and an apparatus for investigating a filling of liquid in a container, e.g. a fuel tank in respect of actual volume, density, temperature, opacity or other condition. From an emitter (19) at the bottom of the container there are emitted pulses of ultrasonic waves which are reflected by one or more horisontal border faces (17, 21) of the liquid and returned to the bottom of the container and detected by a receiver (20) there. The passage times of the reflected signals are compared with the passage times of direct and not-reflected signals that are detected by a plurality of receivers (1, 2, 3, 4, 5) placed above each other in fixed known positions. The result of said comparison is made the basis of a calculation of the sought qualitity. Measurement of the passage times, comparison, calculation and exposition of the result takes place by the use of electronic or data equipment (23).

Method and apparatus for testing liquid fillings in tanks

A multi-frequency ultrasonic liquid level gauging system 30 includes a storage apparatus 34 for storing a volume of liquid 32 and a plurality of ultrasonic transducers 36a-d. Each transducer introduces a distinct ultrasonic signal into the storage apparatus 34 and receives a reflected signal back. A circuit 40 drives and receives signals from the ultrasonic transducers. a processor calculates the liquid level at each of the locations of ultrasonic transducers 36a-d based on the reflected signal received from each transducer. the transducers 36a-d are connected in parallel, thereby allowing the circuit 40 to communicate to the transducers through a single conductive path. A method of measuring a liquid level in the storage apparatus 34 includes emitting a single drive signal to the plurality of ultrasonic signal sources 36a-d, wherein each source is operable to transmit ultrasonic signals having unique frequencies. The ultrasonic signals are transmitted through the liquid 32 and each is reflected at the liquid surface 44. The reflected signals also have unique frequencies and are communicated to a processor. The reflected signals are distinguished and the depth of the liquid level at various storage apparatus locations is calculated from each of the distinguished reflected signals. The depth of the liquid 32 is a function of the propagation time of each signal through the liquid.

Multiple probe ultrasonic liquid level gauging system

A container tilt or slope measurement device measures the inclination of a container relative to the level of liquid in the container and includes at least two sensors (3) mutually spaced apart by a given distance over a given range of liquid levels, and providing output signals depending on the liquid level in the range of the sensor. Also included is an evaluation circuit (11) for detecting an inclination signals derived from the difference of the output signals and spacing of the sensors. The outputs of each of the two sensors (3) are connected specifically to a comparator with the evaluation circuit (11) connected in series therewith.

Liquid level detection using acoustic surface waves

Citations

Filling level measurement

References

Method and apparatus for testing liquid fillings in tanks

Multiple probe ultrasonic liquid level gauging system

Oil level sensor e.g. for motor vehicle

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