Ultrasonic Liquid Level Sensor with Reflector
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Solution Overview
Problem
Conventional liquid level detection systems using ultrasonic sensors face challenges in measuring low liquid levels due to the 'insensitive band' region, where measurement is not possible, and require time-consuming operations.
Innovation Solution
A liquid container design featuring an ultrasonic sensor attached to the outer side wall and a reflecting means at the inner bottom, which reflects ultrasonic waves to the liquid surface, allowing measurement beyond the insensitive band by increasing the distance the wave travels through the liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the ultrasonic sensor is disposed at the bottom portion to enable external measurement, then the container can be cleaned easily, but the liquid level cannot be measured when the level becomes equal to or lower than the insensitive band
Solution Approach 1:
The patent changes the measurement dimension by introducing a reflecting means that creates a folded ultrasonic wave path. Instead of measuring directly from the bottom sensor to the liquid surface (vertical dimension only), the system uses a reflected path that travels from the sensor to the reflecting means and then to the liquid surface, effectively utilizing both vertical and horizontal dimensions to achieve measurement capability at low liquid levels.
2Ease of operation
If the ultrasonic sensor is disposed at the bottom portion, then measurement can be performed from outside the container, but measurement time increases due to repeated displacement operations
Solution Approach 1:
The reflecting means is pre-installed at the bottom portion of the container before measurement begins. This preliminary arrangement of the reflection path eliminates the need for repeated sensor displacement operations, allowing continuous and rapid measurements to be performed from the fixed bottom-mounted ultrasonic sensor.
3Device complexity
If the ultrasonic sensor is disposed at the bottom portion, then the container structure is simplified, but the measurement is affected by the insensitive band of the sensor
Solution Approach 1:
The reflecting means acts as an intermediary element between the bottom-mounted ultrasonic sensor and the liquid surface. This intermediary component enables the ultrasonic wave to reach the liquid surface indirectly by reflection, allowing accurate measurement of low liquid levels without requiring the sensor to be positioned directly above the measurement point, thus maintaining both structural simplicity and measurement precision.
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
Enables rapid and accurate liquid level measurement even at low levels without being affected by the insensitive band, and reduces the impact of bubbles and wave attenuation.
Implementation Method 1
an ultrasonic sensor which is disposed so as to contact an outer side wall of the container main body and so as to emit an ultrasonic wave into the liquid
Implementation Method 2
reflecting means which is disposed at an inner bottom portion of the container main body and reflects an ultrasonic wave emitted into the liquid from the ultrasonic sensor, towards the liquid surface
Implementation Method 3
a liquid level detection means for detecting an absolute value of the level of liquid stored inside the tank, on the basis of the time from emission of the ultrasonic wave until receiving the reflected ultrasonic wave
Data Source
AI summary
A liquid container includes: a container main body which stores a liquid; an ultrasonic sensor which is disposed so as to contact an outer side wall of the container main body and so as to emit an ultrasonic wave into the liquid; and a reflecting means which is disposed at an inner bottom portion of the container main body and reflects the ultrasonic wave emitted into the liquid from the ultrasonic sensor towards a surface of the liquid, the reflecting means being disposed at a position where a distance the ultrasonic wave travels through the liquid in a path of the ultrasonic wave from the ultrasonic sensor to a reflecting surface of the reflecting means, is greater than a distance at which an insensitive band of the ultrasonic sensor is obtained.