Acoustic Liquid Level Sensor With Gas Flow Equalization
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Solution Overview
Problem
Existing devices for measuring liquid levels in tanks face inaccuracies due to slow adaptation to changes in gas composition and temperature, leading to non-optimal levelling of sound speed, especially when the liquid level is low and the distance to the reference portion is large.
Innovation Solution
A device with a waveguide that includes a channel for fluid connection between the reference and measurement portions, where a gas pump creates a flow to equalize gas composition, ensuring accurate acoustic measurements by leveling out differences in gas composition and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference system in the waveguide is used to determine current speed of sound, then the liquid level measurement can be performed, but the device adapts slowly to changes in gas composition and temperature leading to non-optimal levelling of sound speed
Solution Approach 1:
A gas pump is introduced as an intermediary device to actively transport gas between the reference portion and measurement portion of the waveguide. This mediator accelerates the equalization of gas composition and temperature, resolving the slow adaptation problem while maintaining measurement accuracy through active gas flow control.
Solution Approach 2:
The system uses its own internal resources (gas already present in the reference portion) to achieve gas composition equalization. The gas pump circulates and redistributes the existing gas within the waveguide, eliminating the need for external gas sources while achieving rapid adaptation to temperature and composition changes.
2Length of moving object
If the liquid level is low and the distance between the liquid level and the reference portion is large, then the measurement range is extended, but the levelling out effect of the speed of sound becomes non-optimal due to differences in gas composition and temperature
Solution Approach 1:
The gas pump creates controlled pneumatic flow through the waveguide to actively equalize gas composition and temperature across large distances. By using pneumatic principles to circulate gas from the reference portion through the measurement portion, the system maintains uniform acoustic properties even when the liquid level is far from the reference element, enabling accurate measurements over extended ranges.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables more accurate liquid level measurements, even at low levels or large distances, by ensuring consistent gas composition throughout the waveguide, reducing measurement errors and improving the accuracy of acoustic measurements.
Implementation Method 1
a gas pump arranged to create, during operation, a gas flow in the channel from the at least one inlet to the at least one outlet
Implementation Method 2
a waveguide for guiding acoustic signals from the transmitter to the liquid surface and for guiding reflections of the acoustic signals back to the receiver
Implementation Method 3
a receiver adapted to receive reflections of the acoustic signals
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
A device for providing a gas and temperature compensated acoustic measurement of the level of a liquid surface (3), comprising a transmitter (10), a receiver (10), and a waveguide (30) for guiding acoustic signals. The waveguide (30) comprises a reference portion (34) extending from a first end (31) to a reference element (33), and a measurement portion (35) extending from the reference element (33) towards the end (32). The device further comprises a channel (42) extending from at least one inlet (41) in said reference portion (34) to at least one outlet (44) in said measurement portion (35), the channel being separated from the waveguide so as to provide a fluid flow independent of the waveguide, and a gas-pump (40) arranged to create a gas flow in said channel (42) from said at least one inlet (41) to said at least one outlet (44).