Breath Test Simulator Headspace Heater Temperature Control
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Solution Overview
Problem
Existing breath test simulators fail to precisely control the temperature of the headspace and effluent passage, leading to variations in ethyl alcohol concentration, which affects the accuracy of breath test analyzer calibration.
Innovation Solution
A breath test simulator with a headspace heater, featuring a black anodized aluminum lid heated by a resistor, which maintains the headspace temperature and heats the effluent outlet passage to ensure precise temperature control and prevent condensation, using a temperature sensor to activate and deactivate the heater as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an immersion heater is used to heat the water-alcohol solution, then the solution temperature is maintained, but the headspace temperature cannot be precisely controlled due to evaporation cooling and air bubbling
Solution Approach 1:
The heating system is divided into two separate heaters: an immersion heater for the water-alcohol solution and a headspace heater for the effluent in the headspace. This segmentation allows independent temperature control of each zone, enabling precise control of headspace temperature and ethyl alcohol concentration despite evaporation cooling effects.
Solution Approach 2:
A headspace heater is introduced as an intermediary heating element that directly heats the effluent in the headspace. This intermediary heater compensates for the cooling effect of evaporation and air bubbling, allowing precise temperature control of the breath test effluent independent of the solution temperature.
2Quantity of substance
If air is bubbled through the solution to form effluent, then alcohol absorption occurs, but headspace temperature decreases due to evaporation and cooler air
Solution Approach 1:
The headspace heater is activated before and during the air bubbling process to preheat the headspace environment. This preliminary heating action compensates for the anticipated temperature drop from evaporation and cool air introduction, maintaining stable headspace temperature throughout the effluent generation process.
3Ease of manufacture
If the outlet passage is not heated, then heat loss occurs causing condensation and effluent temperature variation
Solution Approach 1:
The outlet passage is integrated with the headspace heater, merging the heating function with the effluent delivery system. This combination ensures that the outlet passage is heated along with the headspace, preventing condensation and maintaining effluent temperature stability without requiring a separate heating system for the passage.
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
This solution allows for very precise temperature control of effluent samples, improving the accuracy of breath test analyzer calibration and maintaining a consistent ethyl alcohol concentration.
Implementation Method 1
A temperature sensor on the lid actuates a switch to activate the resistor when the temperature of the lid falls below a desired temperature... The resistor heats the lid by conduction so that heat radiates evenly down from the lid into the headspace
Implementation Method 2
The resistor heats the lid by conduction so that heat radiates evenly down from the lid into the headspace and heats the effluent in the headspace
Implementation Method 3
An immersion heater heats the solution to a desired temperature
Implementation Method 4
When the solution is at the desired temperature, outside air is bubbled through the solution. Air bubbled through the solution absorbs a known amount of ethyl alcohol from the solution
Data Source
AI summary
A breath simulator for supplying a breath test analyzer with a sample effluent of ethyl alcohol that controls headspace and adjacent effluent passageway temperature.