Mass Flow Sensor Placement in Feed Ducts to Prevent Condensation
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Solution Overview
Problem
Condensation and dew formation on mass flow sensors in combustion apparatuses occur due to temperature drops below the dew point, leading to inaccurate measurements and potential short circuits, and existing solutions like heating or using pressure sensors are either costly or provide incomplete flow information.
Innovation Solution
The mass flow sensor is positioned within the feed duct, with the side duct arranged such that it shares the same temperature as the fluid, ensuring no condensation occurs, and a flow restriction element is used to maintain stable flow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating apparatus is installed to prevent condensation on the sensor, then condensation is avoided, but additional component complexity and operational costs increase
Solution Approach 1:
The patent extracts the sensor from the side duct environment and relocates it to the feed duct where the temperature is inherently higher. By removing the sensor from the cold side duct environment, condensation is avoided without requiring additional heating apparatus, thus resolving the contradiction between reliability and device complexity
Solution Approach 2:
The patent uses the feed duct as an intermediary structure to house the sensor. The feed duct acts as a mediator that provides a warm environment for the sensor while still allowing it to measure flow parameters. This intermediary approach eliminates the need for direct heating of the sensor while maintaining operational reliability
2Reliability
If pressure sensors are used instead of mass flow sensors, then condensation problems are reduced, but direct flow measurement capability is lost
Solution Approach 1:
The patent uses a side duct as a copy or replica of the main feed duct flow path. The side duct contains a simplified flow measurement setup that replicates the flow conditions enough to allow accurate mass flow measurement. This copying approach enables direct flow measurement while avoiding the condensation problems of the main duct environment
3Measurement precision
If mass flow sensor is placed in side duct, then flow measurement is enabled, but condensation occurs on the sensor surface
Solution Approach 1:
The patent transitions the sensor placement from a two-dimensional surface mount in the side duct to a three-dimensional integrated position within the feed duct. By embedding the sensor in the feed duct's internal flow path, the sensor gains access to warmer temperatures while maintaining its measurement function, thus eliminating condensation without sacrificing measurement precision
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
Prevents condensation on the sensor, maintains accurate flow measurements, and ensures stable flow distribution without additional heating components or loss of flow information.
Implementation Method 1
a mass flow sensor (13) between the inlet and the outlet of the side duct (24); wherein the mass flow sensor (13) is configured to detect a signal corresponding to an amount of flow (15) of a fluid through the side duct (24)
Implementation Method 2
the first portion of the side duct (24) is arranged within the feed duct (11)... prevents condensation on the sensor
Data Source
AI summary
Various embodiments include a combustion apparatus. An example apparatus includes: a burner; a side duct; and a feed duct. The side duct comprises an inlet, an outlet, and a mass flow sensor between the inlet and the outlet of the side duct. The mass flow sensor is configured to detect a signal corresponding to an amount of flow of a fluid through the side duct. The side duct comprises a first portion and a second portion. The first portion of the side duct comprises the mass flow sensor. The first portion of the side duct is arranged within the feed duct.