Forced Air Warmer Flow Conditioner for Temperature Sensor Stability
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Solution Overview
Problem
Existing forced air warmers face challenges in accurately measuring the temperature of heated air due to variable errors caused by vortices generated downstream of the temperature sensor, especially when a flexible hose is used, leading to unreliable temperature readings that can result in underheating or overheating of patients.
Innovation Solution
Incorporating an air flow conditioner in the heated air flow path downstream of the temperature sensor to stabilize the air flow, prevent vortex formation, and reduce recirculation of air, thereby improving the accuracy of temperature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is positioned in the heated air flow path to measure temperature, then temperature measurement is enabled, but the air flow becomes unstable and vortices are generated causing variable errors in measurements
Solution Approach 1:
A flow conditioner is introduced as an intermediary component between the temperature sensor and the flexible hose. This flow conditioner stabilizes the air flow downstream of the temperature sensor, preventing vortex formation that would otherwise cause variable measurement errors. The flow conditioner acts as a mediator that decouples the temperature measurement function from the flow disturbance problem.
2Adaptability or versatility
If the flexible hose is used to transport heated air, then the system is adaptable and easy to operate, but the bending profile of the hose affects vortex formation and causes variable measurement errors
Solution Approach 1:
The flow conditioner serves as a buffer between the flexible hose and the temperature sensor. It isolates the temperature measurement zone from the flow disturbances caused by hose bending, allowing the flexible hose to maintain its adaptability while preventing it from affecting measurement precision.
Solution Approach 2:
The flow conditioner modifies the flow parameters (velocity profile, turbulence intensity) downstream of the temperature sensor, creating a stabilized flow regime that is insensitive to variations in hose configuration. This changes the flow state from vulnerable to hose bending effects to a robust, stable state.
3Device complexity
If no air flow conditioner is used, then the device complexity is reduced, but variable errors in temperature measurements occur due to vortex formation
Solution Approach 1:
A relatively simple flow conditioner component is introduced as an intermediary element that provides substantial improvement in measurement reliability. The flow conditioner is designed to be structurally simple (a passive flow management component) but functionally effective at stabilizing the flow and eliminating vortex-induced measurement errors.
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
The air flow conditioner enhances the reliability of temperature measurements, ensuring that the heated air provided by the forced air warmer is accurately regulated, preventing errors and maintaining the intended temperature for patient heating or cooling.
Implementation Method 1
an air heater arranged to heat air within the chamber
Implementation Method 2
an air propagator arranged to propagate heated air from the chamber along a heated air flow path
Implementation Method 3
a temperature sensor provided in the heated air flow path to measure the temperature of heated air
Data Source
AI summary
The invention provides a forced air warmer comprising: a chamber having an outlet port; an air heater arranged to heat air within the chamber; an air propagator arranged to propagate heated air from the chamber along a heated air flow path passing through the port; and a temperature sensor provided in the heated air flow path to measure the temperature of heated air propagated along the heated air flow path. The forced air warmer further comprises an air flow conditioner in the heated air flow path downstream of the temperature sensor, the air flow conditioner being arranged to condition air flow at the temperature sensor so as to improve the reliability of temperature measurements made by the temperature sensor. The forced air warmer may be used to supply heated air to an air warming blanket for regulating the temperature of a patient.