AC Water Level Sensing Probes with Rectifier Circuit
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Solution Overview
Problem
Existing methods for sensing water levels in reservoirs are often expensive and complex due to the need for intricate circuitry and materials that are prone to corrosive breakdown from direct current, necessitating the use of alternating current to mitigate electrolysis.
Innovation Solution
A device using two electrically insulated probes with an air gap, powered by low-voltage alternating current, which generates a control voltage through a shunted full-wave bridge rectifier and solid-state control driver to activate water flow control devices using direct current, simplifying the sensing mechanism and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct current is used to power the sensing probes, then the device can operate with simple electrical power requirements, but the probe material undergoes corrosive breakdown due to electrolysis
Solution Approach 1:
The patent applies periodic action by using alternating current (AC) instead of direct current (DC) to power the sensing probes. The AC current periodically reverses direction, preventing the continuous electrochemical reactions that cause electrolysis and corrosive breakdown of probe materials. This periodic reversal of current direction eliminates the progressive material degradation while maintaining simple electrical power requirements.
2Reliability
If alternating current is used to minimize electrolysis, then probe material stability is improved, but expensive current sensing devices and complex circuitry are required to process the signal
Solution Approach 1:
The patent extracts and eliminates the need for expensive current sensing devices, magnetic field sensors, optics, and complex logic matrices by using the AC current itself as the sensing mechanism. The probes are connected directly to AC power sources, and the presence or absence of water is detected by monitoring the AC current flow through the conductive water path, simplifying the circuitry to basic AC switching without requiring additional sensing components.
Solution Approach 2:
The AC-powered probes perform both power delivery and sensing functions simultaneously. The AC current that would otherwise require separate sensing devices now directly indicates water presence through its conductive path, making the power supply serve the dual purpose of energizing the probes and providing the sensing signal.
3Difficulty of detecting and measuring
If conventional probes are used with intricate control circuitry, then water level sensing capability is achieved, but the overall system cost increases significantly
Solution Approach 1:
The patent replaces complex mechanical and electronic control systems with a simple AC-powered electrical switching mechanism. Instead of using expensive current sensing devices, magnetic field sensors, optical systems, or capacitance networks, the invention uses the fundamental electrical conductivity of water to create a simple on/off circuit that directly controls water flow devices, dramatically reducing system cost while maintaining sensing capability.
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 enables economical and reliable water level sensing and control, reducing the complexity and expense of water flow management systems while preventing corrosive breakdown, allowing for efficient operation of fill, sump, or alarm mechanisms.
Implementation Method 1
low-voltage alternating current (AC) is sent via the probes to a shunted full-wave bridge rectifier which then provides a reference DC voltage output dependent on whether the probes are shorted, electrically open, or at some other state of conductance
Implementation Method 2
When a voltage potential is provided across the probes when submerged in a conducting liquid, a current passing between them is used to create a control voltage in control circuit
Data Source
AI summary
A simplified method and device for sensing water level is disclosed. In particular applications the invention may be used for activating a fill valve or other control circuitry in order to maintain an average level in a reservoir or provide notification of a low fluid level. By incorporating a standard rectifier circuit as a biasing network for a solid-state circuit control driver on one side of a probe network, the level of the water may be determined when contact is made with the probes. AC current drawn across metallic probes provides a DC bias at the output of the rectifier that may be incorporated into various control circuits.