In-line Microwave Warming Apparatus with Integrated Temperature Control
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Solution Overview
Problem
Existing in-line microwave warming apparatuses for blood and fluids are complex, require multiple temperature monitors, have large priming volumes, and suffer from radiation leakage due to their design, which limits their application and increases costs.
Innovation Solution
A simplified in-line microwave warming apparatus with a single-turn tubing cartridge and internal temperature monitors, utilizing a three-dimensional waveguide with a thin slot and internal conductive ridge to minimize radiation leakage and reduce the number of external transducers, featuring a printed circuit with waveguide-to-MIC transitions for efficient temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple temperature monitors (transducers and radiometers) are used to ensure safety, then temperature control reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple temperature monitoring functions into a single integrated temperature sensor positioned within the heating cavity that can detect fluid temperature at critical locations. This eliminates the need for separate transducers and radiometers while maintaining safety through precise internal monitoring.
Solution Approach 2:
The patent introduces an intermediary control system that uses the single temperature sensor's data to regulate microwave heating power. This intermediary controller processes temperature information and adjusts heating intensity accordingly, ensuring safe operation without requiring multiple complex monitoring devices.
2Measurement precision
If multiple cables and external components are used for temperature monitoring, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the temperature sensing function from external components and integrates it directly into the heating cavity structure. The temperature sensor is positioned inside the cavity to directly measure fluid temperature, eliminating the need for external transducers and multiple cables while maintaining measurement accuracy.
3Temperature
If a large cartridge with multiple tubing turns is used, then warming effectiveness is improved, but priming volume increases
Solution Approach 1:
The patent transitions from a multi-turn coiled tubing design to a compact three-dimensional waveguide structure. This dimensional change allows the heating element to achieve effective warming through a more space-efficient configuration, reducing the volume of fluid required to prime the system while maintaining thermal effectiveness.
4Ease of operation
If a large opening is provided in the heating cavity, then cartridge accessibility is improved, but radiation leakage increases
Solution Approach 1:
The patent employs a waveguide structure with controlled aperture dimensions that acts as an electromagnetic barrier. The specific geometry and size of the opening in the waveguide allow cartridge insertion while inherently blocking microwave radiation leakage, eliminating the need for complex ground planes or shields.
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 solution reduces complexity, minimizes radiation leakage, and decreases the priming volume, allowing for precise temperature control with fewer external components, thus enhancing safety and cost-effectiveness while maintaining efficient fluid warming.
Implementation Method 1
Microwave energy has, in the past, been used in connection with the heating of blood and intravenous fluids
Implementation Method 2
heating of blood and intravenous fluids... rapid, uniform heating of the fluid flowing through the cartridge
Implementation Method 3
an external fluid inlet temperature transducer and an external fluid outlet temperature transducer... measure the temperature of the fluid
Data Source
Figure 1
Figure 2~2A
Figure 3
AI summary
Microwave warming apparatus includes a housing defining a heating waveguide with a longitudinal ridge and a heating cavity. A slot extends through the ridge into the heating cavity for receiving a cartridge containing a looped tube so that the tube extends into the heating cavity where the tube contents are heated by energy coupled into the waveguide. Receiving waveguides adjacent to the slot sense the thermal radiation emanating from the tube and deliver corresponding signals to a radiometer which produces a temperature indication. The cartridge includes a support member which maintains the shape of the tube loop. A pair of notches in the support member have walls enabling the notches to complete the receiving waveguides in the housing.