Multi-Heater Flue Gas System Control for Backpressure Stability

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Solution Overview

Problem

Heating systems with multiple heaters on a common flue gas system face instability due to varying exhaust gas back pressures, leading to restricted modulation ranges and issues like misfires and increased emissions, primarily because of the cost disadvantage of additional sensors like mass flow sensors.

Innovation Solution

A method where the operating states of multiple heaters are transmitted to a higher-level management device, allowing for processing and adjustment of operating parameters to adapt to simultaneous operation, thereby reducing the need for additional sensors and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mass flow sensor is installed in the air-exhaust system to help with modulation, then the modulation accuracy and stability are improved, but the system cost increases significantly

Engineering Contradiction:
Improvemodulation stabilityVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a flue gas backpressure sensor as an intermediary device that indirectly measures mass flow information by detecting backpressure changes in the exhaust system. This mediator approach allows the system to obtain modulation control data without directly installing expensive mass flow sensors in the air-exhaust path, thereby resolving the contradiction between measurement accuracy and system cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the modulation range is restricted for multiple occupancy installation, then the operating stability at high or low back pressure is improved, but the device output modulation capability is reduced

Engineering Contradiction:
Improveoperating stabilityVSAvoidmodulation range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic modulation range adjustment based on detected backpressure conditions. The control device automatically adapts the modulation range according to the current operating state and backpressure level, allowing the system to maintain optimal stability while preserving modulation capability across different occupancy scenarios. This dynamic adaptation resolves the contradiction by making the modulation range flexible rather than statically restricted.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (modulation range limits) based on detected backpressure conditions and occupancy state. By dynamically adjusting these parameters, the system maintains stability during high backpressure conditions while preserving full modulation capability when conditions permit, thus resolving the contradiction between stability and adaptability.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the heater continues to ignite with varying starting powers due to varying exhaust gas back pressures, then the ignition adapts to different conditions, but misfires or increased exhaust gas emissions or noises occur

Engineering Contradiction:
Improveignition adaptabilityVSAvoidexhaust gas emissions
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements a feedback control mechanism where the flue gas backpressure sensor continuously monitors exhaust conditions and feeds this information back to the control device. The control device then adjusts the ignition power and combustion parameters in real-time based on this feedback, ensuring optimal ignition under varying backpressure conditions while preventing misfires and reducing harmful emissions. This closed-loop feedback resolves the contradiction by making ignition adaptability precise rather than variable.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3719404B1Method for operating a heating system with multiple components
Publication Date: 2021.12.08 VAILLANT GMBH(DE)
  • EP3719404B1 patent drawingFigure 1~2
  • EP3719404B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a heating system (1) with at least two heating devices (2, 3) connected to a common exhaust system (4), comprising at least the following steps: a) transmitting operating states from the at least two heating devices (2, 3) to a higher-level management unit (5), b) processing the operating states transmitted in step a) by the higher-level management unit (5), c) transmitting at least one result from step b) to at least one of the at least two heating devices (2, 3), d) adjusting at least one operating parameter setting of the at least one of the at least two heating devices (2, 3) when it has been detected that at least two of the heating devices (2, 3) are being operated simultaneously in heating mode.