Environmental Sensor Heating to Reduce Fog and Particle Contamination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing environmental sensors, particularly particulate matter (PM) sensors, are adversely affected by fog and contamination from large particles, leading to inaccurate readings and performance degradation, which is energy-intensive to address and requires frequent maintenance.
Innovation Solution
Utilizing waste heat from the sensor device's components to preheat the sensor gas flow upstream of the environmental sensor, reducing the number and size of evaporable droplets and preventing contamination by large particles through a heat exchanger design and flow barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If measures are taken to evaporate all droplets before they reach the PM sensor, then fog interference is eliminated, but energy consumption increases significantly
Solution Approach 1:
The patent changes the temperature parameter of the sensor housing from ambient to heated condition. By maintaining the housing temperature above the dew point (e.g., 5-15°C higher), water vapor condensation is prevented and existing droplets evaporate, eliminating fog interference without requiring high-energy evaporation measures. This parameter change resolves the contradiction by achieving reliable operation through moderate heating rather than energy-intensive droplet removal.
Solution Approach 2:
The patent converts the harmful effect of fog (water droplets interfering with measurements) into a beneficial situation by heating the housing to maintain temperatures above the dew point. This prevents condensation and promotes evaporation, turning the potential harm of moisture into a controlled environment where water remains in vapor form and does not interfere with optical measurements, thus improving reliability without excessive energy consumption.
2Reliability
If impactors are provided to separate large particles from small particles, then contamination is reduced, but device complexity increases and maintenance requirements arise
Solution Approach 1:
The patent extracts and addresses the root cause of contamination by heating the housing to prevent condensation and particle adhesion in the first place. Instead of adding complex impactor systems to separate particles, the solution removes the underlying problem (condensation creating contamination-prone conditions) through temperature control, thereby reducing contamination without increasing device complexity or maintenance needs.
Solution Approach 2:
The patent applies preliminary action by pre-heating the sensor housing before particles can condense and adhere to surfaces. By maintaining elevated temperature in advance, the housing prevents condensation and particle accumulation before they occur, eliminating the need for subsequent particle separation systems like impactors and their associated complexity and maintenance requirements.
3Use of energy by moving object
If the sensor device operates in cold environments, then energy consumption is reduced, but fog formation increases and affects measurement accuracy
Solution Approach 1:
The patent changes the temperature parameter of the sensor housing from cold (ambient) to warm (heated) condition. By actively heating the housing to maintain temperatures above the dew point, the system prevents fog formation despite operating in cold environments. This parameter change resolves the contradiction by prioritizing measurement accuracy through controlled heating rather than accepting fog-induced errors to save energy.
Solution Approach 2:
The patent converts the harmful effect of cold temperatures (fog formation reducing measurement accuracy) into a beneficial situation by using controlled heating to maintain temperatures above the dew point. This transforms the cold environment challenge into an opportunity to prevent condensation and fog, ensuring accurate measurements without completely eliminating energy consumption, thus balancing reliability and energy use.
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
Reduces the impact of fog and contamination on sensor accuracy without additional energy consumption, enhancing the reliability and longevity of the sensor by minimizing droplet interference and particle ingress.
Implementation Method 1
The sensor device comprises a heat exchanger for exchanging heat between at least a first portion of the sensor gas flow upstream of the environmental sensor and at least a second portion of the sensor gas flow downstream of the environmental sensor
Implementation Method 2
preheat at least a portion of the sensor gas flow upstream of the environmental sensor using waste heat generated by the environmental sensor itself
Implementation Method 3
reducing the number and size of evaporable droplets
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A sensor device (10) comprises an environmental sensor (22) for determining an environmental parameter associated with a sensor gas flow (F2) through the sensor device. The environmental sensor may be a particulate matter sensor for detecting particulate matter in the sensor gas flow. The sensor gas flow is preheated upstream of the environmental sensor (22). To this end, waste heat generated by the environmental sensor (22) itself and/or by a different sensor (12) that is comprised in the sensor device is used. In this manner, the effects of evaporable droplets in the sensor gas flow (F2), as typically present in fog, may be reduced. In some embodiments, a fog signal is derived.