Multi-Tank Air-Pressure Level Sensing for RV Wastewater Tanks
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Solution Overview
Problem
Existing liquid level measurement systems for recreational vehicle holding tanks, particularly black water and gray water tanks, are prone to clogging and inaccuracy, leading to frequent tank draining or overflow risks, as they come into contact with wastewater, and existing indirect methods are not capable of measuring multiple tanks with a single gauge effectively.
Innovation Solution
A multi-tank indirect liquid level measurement system that uses pressure communication to measure liquid levels in freshwater and wastewater tanks, employing a tank selection unit, pressure gage, and normally-closed pressure switch to provide accurate and reliable readings across multiple tanks with a single device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct liquid level measurement devices (conductance, capacitance, floats) are used in wastewater tanks, then liquid level can be measured directly, but the devices are prone to clogging and failure within several weeks
Solution Approach 1:
The patent introduces an intermediary air gap system between the wastewater tank and the measurement device. A tube extends from the tank bottom up into the air space above the liquid, creating an air-filled measurement path. This intermediary air column transmits pressure information from the liquid level without requiring the measurement device to contact the wastewater, thereby maintaining measurement accuracy while eliminating clogging and failure issues.
2Measurement precision
If multiple separate measurement devices are used for each tank, then each tank can be measured accurately, but the system complexity and cost increase
Solution Approach 1:
The patent designs a universal measurement system where a single gauge can measure liquid levels in multiple tanks through a tank selection unit. The system uses a common air supply and pressure transducer that can be switched between different tanks via a selection mechanism, allowing one device to perform the function of multiple separate measurement systems, thereby reducing complexity and cost while maintaining measurement accuracy for each tank.
3Reliability
If indirect pressure measurement is used at the bottom of tanks, then device reliability improves, but the system cannot effectively measure multiple tanks with a single gauge
Solution Approach 1:
The patent implements a dynamic tank selection unit that can switch the connection between the pressure measurement system and different tanks. The selection mechanism allows the system to dynamically reconfigure which tank is being measured by routing the air pressure connection to the selected tank's bottom space. This dynamic switching capability enables a single reliable pressure measurement device to effectively measure multiple tanks, combining reliability with multi-tank versatility.
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
The system allows for easy installation and accurate measurement of liquid levels in multiple tanks, reducing the need for frequent tank draining and minimizing overflow risks, while being cost-effective and easy to use.
Implementation Method 1
measure a liquid level indirectly from the pressure of a liquid at the bottom of a tank or reservoir
Data Source
AI summary
A system and method for measuring liquid levels in a plurality of recreational vehicle holding tanks uses an electric air pump and a selection unit to measure the air pressure required to selectively pump air to the bottom of the holding tanks. The electric air pump is actuated using a user-operated electrical switch and is shut off by a normally-closed pressure switch when the air pressure at the outlet of the electric air pump exceeds a threshold. The liquid level in each tank can be measured using a pressure gage that reads the air pressure downstream of the electric air pump, which equals the pressure of the liquid at the bottom of each tank.