Electronic air pressure interlock switch
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Solution Overview
Problem
Existing gas-fired heating systems, such as HVAC systems and water heaters, rely on single-setpoint pressure switches to ensure the inducer fan is operational before opening the main gas valve, which can be inadequate for multi-stage or modulating systems and lacks comprehensive monitoring for safe and efficient operation.
Innovation Solution
A device incorporating a pressure sensor and processing circuitry that replaces the single-setpoint pressure switch, providing pneumatic communication with the inducer fan and sending signals to control the main gas valve based on predetermined pressure thresholds, allowing for safe operation and data recording for performance monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-setpoint pressure switch is used to sense inducer fan operation, then the system is simple and reliable for basic safety control, but it is inadequate for multi-stage or modulating systems that require multiple pressure thresholds
Solution Approach 1:
The pressure sensor serves multiple functions: it acts as both a safety control device and a diagnostic monitoring device. The single sensor replaces multiple pressure switches while providing continuous pressure data for different operating stages, making the system universally applicable to both single-stage and multi-stage furnaces without requiring additional components
Solution Approach 2:
The patent combines the functions of multiple pressure switches into a single electronic pressure sensor integrated with a microcontroller. This merging consolidates what would traditionally require multiple discrete pressure-switching devices into one unified component that can handle multiple pressure thresholds and provide diagnostic capabilities
2Measurement precision
If multiple pressure switches are installed to provide comprehensive pressure monitoring for multi-stage systems, then all pressure thresholds can be sensed, but the device complexity and number of components increase
Solution Approach 1:
The pressure sensor serves multiple functions: it acts as both a safety control device and a diagnostic monitoring device. The single sensor replaces multiple pressure switches while providing continuous pressure data for different operating stages, making the system universally applicable to both single-stage and multi-stage furnaces without requiring additional components
Solution Approach 2:
The system changes the parameter of pressure threshold detection by using an electronic sensor with programmable thresholds instead of mechanical pressure switches with fixed setpoints. The microcontroller can be configured with different pressure threshold values to accommodate single-stage, multi-stage, or modulating furnace requirements, providing precise measurement without increasing hardware complexity
3Reliability
If traditional pressure switches are used, then safety control is provided, but comprehensive performance monitoring and diagnostic capabilities are lacking
Solution Approach 1:
The system implements feedback by continuously monitoring pressure and providing diagnostic information back to the user or service technician. The microcontroller records pressure data over time and can report on inducer fan performance, allowing for preventive maintenance and troubleshooting while maintaining safety control functions
Solution Approach 2:
The pressure sensor serves multiple functions: it acts as both a safety control device and a diagnostic monitoring device. The single sensor replaces multiple pressure switches while providing continuous pressure data for different operating stages, making the system universally applicable to both single-stage and multi-stage furnaces without requiring additional components
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 ensures safe and efficient operation by allowing the main gas valve to open only when the inducer fan provides sufficient pressure, enhancing safety and diagnostic capabilities, particularly in multi-stage systems, by replacing multiple pressure switches with a single sensor and providing performance data for improved diagnostics.
Implementation Method 1
a pressure sensor in fluid communication with the combustion air and configured to measure the pressure of the combustion air and to output a signal proportional the measured pressure
Data Source
AI summary
A device that includes a pressure sensor that adds dynamic pressure sensing capability to a furnace. In some examples the device may include a relay and other circuitry to replace the single-setpoint pressure switch used to sense the operation of an inducer fan. The pressure sensor may measure the pressure from the inducer fan and send a signal to the other circuitry, such as a microcontroller. The other circuitry may determine when the pressure from the inducer fan reaches a predetermined threshold and allow the main gas valve of the furnace to open. The other circuitry may be configured to set the pressure sensor to a variety of predetermined pressure thresholds, and thereby replace multiple pressure switches. In some examples, the other circuitry may record pressure values received from the pressure sensor over time and provide performance data, as well as other signals or indicators.