Portable indirect fuel fired heater with automated combustion optimization
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Solution Overview
Problem
Portable construction heaters face challenges in maintaining optimal combustion across varying environmental conditions, including altitude, temperature, and fuel type/density changes, due to fluctuations in air density and fuel properties, which affects the air/fuel ratio and requires continuous manual adjustment to ensure reliable and safe operation.
Innovation Solution
A fully automatic combustion control system using an oxygen sensor to continuously adjust the air/fuel ratio by varying the combustion air blower rate, with an actuator and controller maintaining a prescribed oxygen set point, allowing the heater to adapt to different conditions without manual supervision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual adjustment of air/fuel ratio is used, then the heater can operate in varying environmental conditions, but continuous personnel supervision is required which reduces productivity and increases operational complexity
Solution Approach 1:
The heater system performs self-adjustment of the air/fuel ratio through an automated control system that senses oxygen levels in exhaust gases and modifies combustion air blower rate accordingly, eliminating the need for continuous manual supervision and personnel intervention while maintaining optimal combustion across varying environmental conditions
Solution Approach 2:
The system incorporates a combustion control system with oxygen sensing that continuously monitors exhaust gas composition and provides feedback to the controller, which then adjusts the combustion air blower rate to maintain optimal air/fuel ratio, creating a closed-loop control system that adapts automatically to changing conditions
2Adaptability or versatility
If manual adjustment of air/fuel ratio is used, then the heater can adapt to different fuel types and densities, but requires continuous personnel intervention which increases device complexity
Solution Approach 1:
The automated combustion control system performs self-adjustment by sensing oxygen levels in exhaust gases and automatically modifying the combustion air blower rate to compensate for variations in fuel type, density, and energy content, eliminating the need for personnel to manually adjust settings for different fuels
Solution Approach 2:
The system replaces manual mechanical adjustment mechanisms with an automated electronic control system that uses oxygen sensing technology and electronic actuators to modify combustion air flow, reducing operational complexity while maintaining adaptability to different fuel types
3Ease of operation
If fixed air/fuel ratio is used, then the combustion system is simpler to operate, but combustion efficiency deteriorates under varying environmental conditions such as altitude and temperature changes
Solution Approach 1:
The system transitions from a fixed air/fuel ratio to a dynamic, continuously adjustable ratio by incorporating an automated control system that modifies the combustion air blower rate in real-time based on oxygen sensing feedback, allowing optimal combustion efficiency across varying environmental conditions while maintaining ease of operation through automation
Solution Approach 2:
The control system dynamically changes the combustion air flow parameter in response to sensed oxygen levels, automatically adjusting the air/fuel ratio to maintain optimal combustion efficiency across different altitudes, temperatures, and fuel types without requiring manual intervention
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
Enables reliable and consistent operation of portable construction heaters across a wide range of environmental conditions and fuel types, ensuring optimal combustion and safety without the need for continuous personnel intervention.
Implementation Method 1
a combustion sensor in communication with the combustion passage so as to be arranged to sense an oxygen level in the exhaust gases
Implementation Method 2
a heat exchanger defining a heating air passage extending therethrough from a heating inlet to the heating outlet of the heater for receiving air to be heated therethrough, the heat exchanger being in heat exchanging relationship with at least a portion of the combustion passage
Implementation Method 3
combusting the fuel in the combustion chamber to produce exhaust gases
Data Source
AI summary
A portable indirect fuel fired heater includes a burner assembly having a fuel burner to deliver fuel from a fuel supply to a combustion chamber of the heater and a combustion air blower to deliver combustion air to the combustion chamber with the fuel for combustion in the combustion chamber to produce exhaust gases. A heat exchanger receives air to be heated in heat exchanging relationship with at least a portion of the combustion chamber. A sensor senses an oxygen level as a partial pressure of oxygen in the exhaust gases. A controller operates an actuator operatively connected to the burner assembly to controllably vary the delivery rate of combustion air and thus vary the ratio of the air and fuel responsive to the oxygen level sensed by the combustion sensor so as to maintain the sensed oxygen level at a prescribed set point level stored on the controller.