System and method for operational control of a water heater apparatus with a combustible gas burner
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Solution Overview
Problem
In water heater systems with intermittent pilot burners, detecting the effective ignition of the main burner is crucial to prevent malfunctions and potential explosions, but existing methods, such as using a second electrode, increase system complexity and costs, and fail to safely manage valve closure issues.
Innovation Solution
A control system that uses a single flame detection electrode to measure the ionization current, distinguishing between the ignition states of the pilot burner alone and the main burner by detecting variations in ionization current intensity, and introduces a delay between valve closures to ensure safe extinguishing of the main burner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a second electrode with a second flame detector is used to detect the effective ignition state of the main burner, then the detection accuracy is improved, but the system complexity and costs increase significantly
Solution Approach 1:
The single electrode serves multiple functions: detecting the pilot flame presence and detecting the main burner ignition state by measuring ionization current variations. The control unit processes different ionization current patterns to distinguish between pilot-only operation and main burner operation, eliminating the need for separate detection systems.
Solution Approach 2:
The system detects changes in ionization current parameters (intensity variations) to differentiate between different burner states. By monitoring the magnitude and pattern of ionization current changes, the system can identify when the main burner is effectively ignited without requiring additional sensors.
2Loss of energy
If the pilot valve is closed immediately when the temperature setpoint is reached, then the energy efficiency is improved, but the safety is worsened due to the risk of explosion during subsequent pilot ignition
Solution Approach 1:
The control unit performs preliminary detection of main burner ignition status using ionization current measurement before closing the pilot valve. This preliminary action ensures that the system confirms safe conditions (main burner is off and combustion chamber is clear) before allowing pilot valve closure and subsequent re-ignition sequences.
Solution Approach 2:
The system continuously monitors ionization current to provide feedback on the actual combustion state. This feedback mechanism allows the control unit to make informed decisions about valve closure timing, ensuring that the pilot valve is only closed when the main burner is confirmed to be off, thereby preventing dangerous gas accumulation and explosion risks.
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 approach allows for effective ignition detection of the main burner, managing potential faults and preventing explosions by containing costs and complexity, while ensuring safe operation and reducing the risk of gas flow mismanagement.
Implementation Method 1
a flame detection electrode which is provided to be introduced into the flame of the pilot burner and which is configured to conduct an ionization current which is generated by ionizing effect produced by the flame
Data Source
AI summary
A control system of a water heater apparatus with a combustible gas burner is presented where the apparatus includes a pilot burner with an intermittent-type pilot flame, a main burner, a pilot valve and a main valve, a control unit, a flame detection electrode, introduced into the flame of the pilot burner, and which is configured to conduct an ionization current. The control unit is configured to measure/detect a variation involving increase/decrease of the intensity of ionization current detected, the variation in intensity of ionization current being generated during the change between a first condition, in which the ionization current identifies the ignition state of only the pilot burner, and a second condition, in which the ionization current identifies the simultaneous ignition state of the pilot burner and the main burner so that, by detection of the measurement/variation of ionization current, the effective ignition of the main burner is recognized.