Aircraft Lavatory Tank Measurement Using External Support Rod Load Cells
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Solution Overview
Problem
Existing tank measurement systems for storing liquid and solid materials, particularly those used in aircraft lavatories, are prone to failures due to sensor fouling, leading to erroneous readings and high maintenance costs, and are not sanitary or efficient.
Innovation Solution
A tank measurement system using unobtrusive load measurement sensors integrated into support rods that hang the tank within the aircraft fuselage, generating output signals proportional to the tank's weight, with software algorithms compensating for rod failures and allowing external measurement without drilling into the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If probes and sensors are inserted into the tank for measurement, then measurement capability is achieved, but sensor fouling occurs leading to erroneous readings and premature shutdown
Solution Approach 1:
The measurement system is extracted from the tank interior to the exterior. Load cells are mounted on support rods outside the tank, eliminating the need for probes inserted into the tank. This extraction removes the sensors from the fouling environment while maintaining measurement capability through external weight measurement.
Solution Approach 2:
The support rods act as intermediaries between the tank and the measurement system. The load cells are mounted on these rods, which transmit the tank's weight to the sensors without requiring direct contact between sensors and tank contents. This intermediary structure enables measurement while preventing fouling.
2Reliability
If multiple sensors are installed for redundancy, then reliability is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The system uses the existing support rod structure as the measurement platform, extracting the measurement function from complex internal sensor installations to simple external load cell mounting. This reduces device complexity while maintaining reliability through the inherent redundancy of multiple support rods.
3Measurement precision
If wash nozzles are installed to clean sensors, then measurement accuracy is maintained, but water consumption increases and maintenance becomes less sanitary
Solution Approach 1:
By extracting sensors from the tank interior to external load cells on support rods, the system eliminates the need for wash nozzles entirely. The sensors are positioned where they can be easily accessed for cleaning without requiring water injection systems, thus eliminating water consumption and improving sanitation.
Solution Approach 2:
The external positioning of load cells on support rods allows for easy manual cleaning and maintenance without complex automated wash systems. The design enables self-service maintenance where technicians can directly access and clean sensors without elaborate water delivery infrastructure.
4Measurement precision
If holes are drilled in the tank for sensor insertion, then measurement capability is achieved, but tank integrity and manufacturing complexity are compromised
Solution Approach 1:
The measurement system is completely extracted from the tank structure, using external support rods and load cells instead of drilling holes in the tank. This preserves tank integrity and simplifies manufacturing by eliminating the need for sensor openings, welds, or seals in the tank body.
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 provides a more accurate, reliable, and low-maintenance tank measurement system, reducing maintenance delays and costs, while maintaining passenger comfort and convenience by eliminating the need for elaborate wash nozzles and minimizing contact with hazardous materials.
Implementation Method 1
Each of these support mechanisms generates an output signal proportional to the weight of the tank
Data Source
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AI summary
A measurement system for a tank includes a tank configured to contain material, a plurality of support rods to support the tank and each of the plurality of support mechanisms including a load measurement sensor. The system further including a weight measurement circuit configured to determine an amount of material contained in the tank in response to the load measurement sensor.