Optical Liquid Level Measurement System for Dairy Dispensing
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Solution Overview
Problem
Existing liquid level determination systems for gravity-aided dispensing systems, such as those used in dairy product dispensers, face challenges including calibration complexities due to temperature variations, residual product accumulation, and variability in tank geometry, leading to inaccurate volume dispensing and potential contamination risks.
Innovation Solution
An optical liquid height determination system is implemented with a translucent tank and light sensors positioned within a container, using infrared light sources and sensors to calculate liquid levels based on calibrated signal values, eliminating the need for direct tank attachment and reducing temperature-dependent errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load cells or pressure sensors are used to measure liquid level, then liquid level can be determined, but calibration complexity increases due to temperature variations, residual product accumulation, and tank geometry variability
Solution Approach 1:
The patent replaces mechanical load cells and pressure sensors with an optical measurement system using light sources and light sensors. This substitution eliminates the need for mechanical contact with the liquid, removing sources of contamination and reducing calibration complexity related to temperature and residual product accumulation. The optical system measures liquid level by detecting light transmission through the liquid column without requiring physical interaction with the liquid or tank contents.
Solution Approach 2:
The patent introduces an optical intermediary system (light source and light sensor) that indirectly measures liquid level by detecting changes in light transmission properties. Instead of directly measuring weight or pressure, the system uses light as an intermediary to detect liquid column height, thereby avoiding the calibration issues associated with direct mechanical measurement methods.
2Measurement precision
If photodiodes are affixed to the tank to sense light, then liquid level can be detected, but contamination risk increases and cleaning becomes difficult
Solution Approach 1:
The patent extracts the light sensing function from direct contact with the liquid by positioning light sensors on the external surface of the tank rather than immersing them in the liquid. The sensors detect light transmitted through the liquid column from the outside, eliminating the need for liquid contact and thereby removing contamination risks and cleaning requirements for the sensing components.
Solution Approach 2:
The patent replaces direct liquid-contacting photodiodes with an optical system where light sensors remain external to the liquid. This substitution maintains liquid level detection capability while eliminating the harmful contamination effect by ensuring no part of the measurement system enters the liquid.
3Measurement precision
If multiple light sensors are positioned on the tank wall, then liquid level measurement is possible, but manufacturing complexity and component costs increase
Solution Approach 1:
The patent segments the measurement function into a light source positioned at one location and light sensors positioned at another location on the tank. This segmentation allows for simpler individual components that can be manufactured separately and assembled, reducing overall manufacturing complexity compared to integrating multiple sensors directly into the tank wall structure.
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 system provides accurate and consistent liquid level measurements across various temperatures and products, reducing component costs and preventing contamination, while allowing for easy tank installation and maintenance without electrical connections.
Implementation Method 1
The at least two light sensors are attached to a second inner wall of the compartment and proximate to a wall of the tank for generating respective electrical signals in response to the received light, where the specific liquid blocks or attenuates light from the light source reaching the at least two light sensors
Data Source
AI summary
An optical liquid height determination system of the present embodiments includes light sensors capturing different amounts of light, based on level of liquid in the tank that blocks or limits light to particular sensors. The tank is enclosed in a container with a light source and the light sensors are installed on walls of the container. Light emitted by the light source is transmitted to the light sensors by passing through the liquid product, scattered, diffused, diffracted or reflected by the dairy product, through the tank walls which may be transparent or translucent, or from other surfaces in the container within which the tank is enclosed by. The set of electrical signals received from all the light sensors are compared against sets of calibrated signals corresponding to known liquid levels in the tank. The known height corresponding to the nearest set of calibrated signals is determined as the measured liquid height in the tank.