Warm Air Heater Combustion Fan Control for Altitude Compensation

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Solution Overview

Problem

Existing forced supply and exhaust type warm air heaters require manual adjustments and additional devices to maintain optimal combustion states across varying altitudes, which is inefficient and labor-intensive.

Innovation Solution

A warm air heater system that includes a differential pressure detection unit to adjust the rotation speed of the combustion fan and fuel supply based on detected differential pressure, ensuring optimal combustion regardless of altitude without additional devices or manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an air pressure sensing circuit is added to sense air pressure of combustion air, then the combustion state can be optimized regardless of altitude, but the device complexity increases

Engineering Contradiction:

Improvecombustion optimization across altitudesVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The differential pressure detection unit is integrated into the existing air supply passage system to serve dual purposes: it detects differential pressure for combustion optimization while also functioning as part of the overall air flow control mechanism. This multi-functional integration allows altitude compensation without adding separate dedicated sensing systems, thereby resolving the contradiction between adaptability and device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the existing air supply passage structure itself to provide the detection function. The differential pressure detection unit leverages the natural pressure differential created by air flow through the passage, eliminating the need for external power sources or complex sensing circuits. The system essentially detects and corrects its own operational parameters using integrated sensors and control logic

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If air dampers with different hole areas are installed according to altitude, then the combustion air quantity can be optimized, but the ease of manufacture decreases due to multiple components

Engineering Contradiction:

Improvecombustion air quantity optimizationVSAvoidease of manufacture

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of using multiple static air dampers with fixed hole areas for different altitudes, the system employs a single adjustable air damper whose opening area can be dynamically modified. The degree of opening is controlled based on differential pressure detection, allowing the same physical component to adapt to various altitude conditions. This dynamic adjustment capability eliminates the need for manufacturing multiple damper variants while maintaining optimization performance

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter (air damper opening area) rather than changing the physical component itself. By controlling the opening area of a single air damper based on detected differential pressure, the system achieves altitude-specific combustion optimization without requiring multiple dampers with different fixed geometries, thereby simplifying manufacturing

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If switches are manually set according to installation altitude, then the combustion state can be optimized, but the ease of operation decreases due to manual setup requirements

Engineering Contradiction:

Improvecombustion state optimizationVSAvoidease of operation

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system implements automatic feedback control where the differential pressure detection unit continuously monitors the actual air flow conditions, and the combustion control unit automatically adjusts the air damper opening area and fuel supply based on the detected differential pressure. This closed-loop feedback mechanism eliminates the need for manual altitude-based switch settings, as the system self-adjusts to maintain optimal combustion states across different installation altitudes

Inventive Principle:

Principle #23Feedback

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

The system automatically optimizes combustion states by correcting fan speed and fuel supply quantities based on air density changes, maintaining optimal combustion performance across different altitudes without the need for manual adjustments or additional devices.

Implementation Method 1

a differential pressure detection unit which detects differential pressure between front and rear of the orifice in the air supply passage

Methodology Applied

Scientific EffectDifferential pressure detection: Pressure Drop

Implementation Method 2

a combustion fan which is disposed in the air supply passage, and supplies air in the outdoors to the combustion chamber through the air supply passage

Methodology Applied

Scientific EffectForced convection: Forced Convection

Data Source

PatentUS10113770B2Warm air heater

Publication Date: 2018.10.30 RINNAI CORP

AI summary

An orifice 26 is provided in an air supply passage 5a of a warm air heater 100, and a differential pressure sensor 28 detects differential pressure Δp between front and rear of the orifice 26 in the air supply passage 5a. Rotation speed of the combustion fan 24 is corrected on the basis of the differential pressure Δp detected by the differential pressure sensor 28.