Capacitance Probe for Grease Interceptor Level Analysis
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Solution Overview
Problem
Conventional grease interceptors lack efficient and automated methods for measuring FOG (fats, oils, grease) and sludge levels, leading to high maintenance costs and inaccuracies due to reliance on manual methods or prone-to-fouling ultrasonic and resistivity-based technologies.
Innovation Solution
A capacitance-based grease interceptor level analyzer with a fixed or portable probe featuring electrode ring pairs and a microprocessor algorithm for real-time measurement of FOG, water, sludge, and air levels, using a daisy chain arrangement for varying heights and communication via LoRa or Bluetooth for remote monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic transducer and receiver are used to measure FOG levels, then electronic measurement capability is provided, but the device fouls easily and is confused by spurious reflections
Solution Approach 1:
The patent replaces the ultrasonic transducer system with a capacitance-based sensing system. Instead of using ultrasonic waves that are prone to fouling and spurious reflections, the invention uses electrical capacitance measurements between a probe electrode and a reference electrode to detect FOG levels. This substitution of the measurement mechanism eliminates the fouling problem while maintaining measurement capability.
2Ease of manufacture
If resistivity-based measurement with electrodes is used, then the method is simple and inexpensive, but the oily environment quickly coats the electrodes and decreases measured resistivity
Solution Approach 1:
The patent changes the measurement parameter from resistivity to capacitance. While resistivity measurements are simple and inexpensive, they are highly sensitive to electrode coating by oil. The invention switches to capacitance measurements, which are less sensitive to the oily environment. The capacitance-based system measures the dielectric properties of the FOG layer rather than electrical resistance, thereby avoiding the fouling problem while maintaining ease of manufacture.
3Ease of manufacture
If manual core sampler is used to measure FOG levels, then upfront cost is low, but operating costs are very high due to time required for measurement and cleaning
Solution Approach 1:
The patent implements an automated capacitance-based measurement system that continuously or periodically monitors FOG levels without requiring manual intervention. The system self-measures the FOG layer thickness by detecting capacitance changes, eliminating the need for manual sampling, measurement, and cleaning operations. This automation significantly reduces time loss while keeping device costs reasonable through the use of simple capacitance sensing circuitry.
4Measurement precision
If ultrasonic analyzer is used, then electronic measurement is provided, but it is limited to large interceptors due to fouling and spurious reflections
Solution Approach 1:
The patent replaces the ultrasonic measurement system with a capacitance-based system that is not subject to fouling and spurious reflections. This substitution enables the measurement system to work effectively in both large and small interceptors. The capacitance probe can be positioned close to the FOG-water interface even in small interceptors without suffering from the limitations that plague ultrasonic systems, thereby achieving universal adaptability across different interceptor sizes.
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 accurate, real-time, and cost-effective monitoring of grease interceptor contents, reducing the need for frequent servicing and providing reliable data transmission to minimize regulatory compliance issues and maintenance costs.
Implementation Method 1
A capacitance-based grease interceptor level analyzer with a fixed or portable probe featuring electrode ring pairs
Data Source
AI summary
An analyzer for a grease interceptor for measuring identity of materials and levels of fat, oil, and grease (FOG), water, sludge and air having a probe which includes a controller and a sensor sub-unit. Sensor circuits include a microcontroller, timers, and sampling capacitors. The sensor sub-unit includes a plurality of electrode ring pairs coupled to a plurality of timers for converting capacitance measurements to frequencies under the control of a microprocessor in the controller. The frequencies identify the measured levels. A calibration of the probe converts a range of frequency values of each sensor circuit to an arbitrary scale for improved accuracy.