Sealed Fluid Temperature Sensing With Active Heat-Flow Feedback
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Solution Overview
Problem
Measuring temperature in medical devices is challenging due to sealed and sterile fluid flow paths, which complicates the introduction of temperature sensors without contamination risk, and requires high accuracy for diagnostic purposes while avoiding clot formation and ensuring compatibility with disposable components.
Innovation Solution
The development of active temperature measurement devices that include a fluid-side temperature sensor and a heating/cooling device, combined with a controller to regulate heat flow, allowing for precise temperature measurement within sealed fluid circuits by maintaining the sensor temperature equal to the fluid temperature, thus minimizing measurement errors and response time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is introduced into the sealed sterile fluid flow path, then temperature measurement capability is improved, but the risk of contamination increases
Solution Approach 1:
The patent uses the vessel wall as an intermediary medium to transmit temperature information from the fluid to the sensor. The sensor remains outside the sterile fluid path while measuring temperature through the wall, eliminating direct contact and contamination risk while maintaining measurement capability
Solution Approach 2:
The patent replaces direct mechanical contact between sensor and fluid with thermal conduction through the vessel wall. This substitution allows temperature measurement without physical penetration of the sterile barrier, solving the contamination problem
2Device complexity
If heat flow through the vessel wall is present, then temperature measurement is simplified, but measurement accuracy deteriorates
Solution Approach 1:
The patent employs a feedback control system where a heater adjusts its power output based on the temperature difference between the inner and outer sensor readings. This active compensation eliminates heat flow through the wall while maintaining measurement accuracy, resolving the contradiction between simplicity and precision
Solution Approach 2:
The system preemptively counteracts heat flow through the vessel wall by using the heater to maintain thermal equilibrium. This preliminary anti-action prevents measurement errors before they occur, ensuring accuracy without requiring complex measurement techniques
3Measurement precision
If the sensor temperature differs from fluid temperature, then heat flow occurs through the wall, but response time is reduced, then measurement accuracy improves
Solution Approach 1:
The feedback control system continuously monitors temperature differences and adjusts heater power in real-time. This dynamic control achieves both rapid response (by allowing initial temperature differences) and high accuracy (by compensating for resulting heat flow), resolving the time-accuracy tradeoff
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 enables accurate and rapid temperature measurement in medical fluids, reducing errors caused by heat flow through the vessel wall and ensuring compatibility with disposable medical components, thereby enhancing diagnostic precision and safety.
Implementation Method 1
A temperature sensor is attached to or placed against a wall of a vessel/channel configured for carrying or containing a fluid
Implementation Method 2
a heating/cooling device, combined with a controller to regulate heat flow, allowing for precise temperature measurement within sealed fluid circuits by maintaining the sensor temperature equal to the fluid temperature
Data Source
AI summary
A system for measuring electrical conductivity includes a fluid conduction measuring circuit and a temperature measuring element having at least one thermal contact portion with a temperature sensor and a temperature measuring circuit. A controller is configured to control the conduction measuring circuit and the temperature measuring element. A fluid circuit is configured to carry a fluid and has a wetted conductor inside a conductivity cell portion, the wetted conductor having a contact, external to the fluid circuit, for interfacing with the fluid conduction measuring circuit. Further, at least one temperature measurement portion has predefined thermal properties and is configured to touch the thermal contact portion. The controller controls the temperature measuring element and the conduction measuring circuit to generate and output at least one set of contemporaneous temperature and conduction measurements.