Intermittent Pilot Water Heater Control for Safe Main Gas Ignition
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Solution Overview
Problem
In intermittent pilot water heater systems, there is a risk of uncombusted fuel discharge into enclosed spaces due to the potential initiation of the main gas flow before the establishment of an active pilot flame, especially when the system is not connected to line voltage, where thermoelectric devices may not generate sufficient voltage and current to ensure safe operation.
Innovation Solution
The system incorporates a thermoelectric device that generates electrical power only when a pilot flame is established, using this power to energize the main gas valve operator, ensuring that the main gas flow to the burner is initiated only after a stable pilot flame is maintained, with an energy storage system providing backup power for the pilot valve operator when the thermoelectric device is not generating electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main gas valve is interlocked with pilot light operation to prevent uncombusted fuel discharge, then safety is improved, but the system complexity increases due to additional interlocking mechanisms
Solution Approach 1:
The patent combines the safety interlocking function with the existing pilot light control system by integrating the thermoelectric device into the valve operator circuitry. The thermoelectric device generates voltage only when the pilot flame is present, and this voltage directly controls the main gas valve operator, merging the safety detection and valve control functions into a unified system rather than adding separate interlocking mechanisms.
Solution Approach 2:
The thermoelectric device provides self-service safety interlocking by automatically generating the control voltage for the main gas valve operator based on the presence of the pilot flame. The system uses its own operational state (pilot flame presence) to automatically control the main gas flow without requiring external monitoring or additional control logic, making the safety function self-regulating.
2Adaptability or versatility
If a thermoelectric device is used to generate voltage and current without line voltage connection, then system adaptability is improved, but the available electrical power decreases
Solution Approach 1:
The patent changes the electrical parameters (voltage and current) available to the valve operators based on the operational mode. When the thermoelectric device is generating power, the system operates with limited electrical parameters suitable for safe main gas valve control. The system adapts its electrical parameter requirements to match the available power from the thermoelectric device, rather than requiring constant high-power availability.
Solution Approach 2:
The system uses partial electrical action by providing just enough voltage and current from the thermoelectric device to safely control the main gas valve operator, rather than providing full line voltage power. The thermoelectric device generates sufficient power for the critical safety function of controlling main gas flow based on pilot flame presence, without requiring excessive electrical capacity.
3Object-affected harmful factors
If the main gas flow is restricted until pilot flame establishment is confirmed, then harmful factors are reduced, but the response time increases
Solution Approach 1:
The system performs preliminary action by requiring the pilot flame to be established and generating voltage on the thermoelectric device before allowing the main gas valve to open. This preliminary verification of pilot flame presence ensures that the main gas flow will be immediately combusted when released, preventing uncombusted fuel discharge while maintaining a rapid response once the condition is met.
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 effectively prevents the discharge of uncombusted fuel into enclosed spaces by ensuring that the main gas flow is only initiated once a pilot flame is established, even in the absence of line voltage, thereby enhancing safety and operational reliability.
Implementation Method 1
a thermoelectric device that converts thermal energy from the flame into electrical energy to power components of the water heater
Data Source
AI summary
A water heater control system comprising an energy storage system electrically connected to a pilot valve operator and electrically isolated from a main valve operator. The energy storage system may be electrically connected to an ignition circuit. A thermoelectric device is in thermal communication with the pilot flame and electrically connected to a main valve operator. The water heater system may include a microcontroller configured to establish electrical communications between the device and the energy storage system, the pilot valve operator, and the main valve operator. The microcontroller may be configured to recognize a call for main burner operation, and may also be configured to check an available voltage of the energy storage system against a setpoint. The microcontroller may establish pilot flame operation with or without main burner operation, depending on whether a call for heat or recharging of the energy storage system is required.