Gas Water Heater Exhaust Fan Control for Wind Pressure Stability
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Solution Overview
Problem
Existing gas water heaters face issues with high device costs and operational interruptions due to wind pressure fluctuations, which affect combustion efficiency and safety, particularly in Q-type and G-type models.
Innovation Solution
A safety control system for gas water heaters that adjusts the exhaust fan's rotational speed and output power based on the difference between actual and reference values, ensuring optimal combustion conditions by actively controlling air volume and shutting off the system in extreme wind pressure situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wind pressure detecting unit is adopted to detect wind pressure and control the exhaust fan, then combustion safety is improved, but device cost increases and operational interruptions occur due to slight wind pressure
Solution Approach 1:
The patent extracts the wind pressure detection function from a separate detecting unit and integrates it into the control system through motor current monitoring. Instead of adding a dedicated wind pressure sensor, the system uses the existing motor current signal to infer wind pressure conditions, thereby eliminating the need for additional expensive sensors while maintaining safety monitoring capability.
Solution Approach 2:
The patent introduces motor current as an intermediary parameter to indirectly detect wind pressure conditions. Rather than directly measuring wind pressure with a sensor, the system uses motor current as a mediator that reflects the relationship between motor output and wind pressure, enabling safety monitoring through electrical parameter analysis instead of direct mechanical pressure sensing.
2Reliability
If a wind pressure detecting unit is used to ensure safe combustion, then combustion safety is improved, but operational continuity deteriorates due to interruptions from slight wind pressure
Solution Approach 1:
The patent changes the detection parameter from direct wind pressure measurement to motor current analysis. By monitoring changes in motor current under different wind pressure conditions, the system can distinguish between normal operational variations and actual safety hazards, allowing it to maintain operation during slight wind pressure fluctuations while still detecting dangerous conditions that require shutdown.
Solution Approach 2:
The patent applies partial monitoring action by focusing on specific motor current characteristics that indicate dangerous wind pressure conditions rather than responding to all current variations. The control system analyzes current patterns to determine when wind pressure actually threatens safety, avoiding unnecessary operational interruptions caused by minor or normal wind pressure changes.
3Productivity
If the exhaust fan rotational speed is controlled based on wind pressure detection, then combustion efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the wind pressure detection function with the existing motor control system by using the same microcontroller and current sensing circuitry. The control system that already manages exhaust fan rotation is enhanced to also monitor wind pressure conditions through current analysis, eliminating the need for separate detection and control systems while achieving both efficient exhaust control and safety monitoring.
Solution Approach 2:
The patent makes the motor control system multi-functional by enabling it to perform both its primary function of controlling exhaust fan rotation for combustion efficiency and the secondary function of detecting wind pressure conditions for safety. The same control unit and current sensors serve dual purposes, reducing overall system complexity while achieving multiple objectives simultaneously.
Data Source
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AI summary
Embodiments of the present invention provide a gas water heater and a safety control method and system for the same. The system includes: an exhaust fan; a rotational speed detecting unit, configured to detect a rotational speed of the exhaust fan; a power obtaining unit, configured to obtain a set value for output power of the exhaust fan; a rotational speed difference obtaining unit, configured to obtain an actual value of the rotational speed and a reference value of the rotational speed according to the set value for the output power, and to calculate a difference between the actual value of the rotational speed and the reference value of the rotational speed; and an exhaust control unit, connected to the exhaust fan, the rotational speed detecting unit and the power obtaining unit respectively, and configured to correct the rotational speed of the exhaust fan according to the difference, to determine a wind pressure situation at an air outlet of the exhaust fan according to corrected rotational speed and the set value for the output power, and to adjust the set value for the output power according to the wind pressure situation. The system can ensure that the gas water heater has a good combustion condition and can ensure that the gas water heater operates safely and reliably, and can improve the control accuracy.