Infusion fluid warmer comprising printed circuit board heating elements
Inventors
Assignees
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Publication Number
US-12138435-B2
Publication Date
2024-11-12
Expiration Date
Abstract
The present invention relates to an infusion fluid warmer comprising a heat exchanger and first and second printed circuit boards comprising respective integrally formed electrically resistive patterns acting as heating elements. The integrally formed electrically resistive patterns are heated by supply of electrical power and thermally coupled to a heat exchanger to warm an infusion fluid flowing through a fluid passage of the heat exchanger.
Core Innovation
An infusion fluid warmer includes a DC power supply input, a first carrier board with an integrally formed electrically resistive pattern, and a heat exchanger with an aluminium upper wall structure and a lower opposing wall structure separated by a fluid channel extending between fluid inlets and outlets. The fluid channel extends substantially straight along a longitudinal axis of the heat exchanger, and an outer surface of the upper wall structure is thermally connected to the first resistive pattern.
The controller connects the DC power supply input to the first or second integrally formed electrically resistive pattern to serve as a heating element during a first time period. During measurement time periods, the controller determines temperature from measured pattern resistance, based on circuitry that can include controllable semiconductor switches and, optionally, a reference resistor and switching circuitry.
The disclosure further constrains the fluid-channel geometry by specifying that a width-to-thickness ratio of a central zone of the fluid channel is at least 50:1 or at least 175:1 or at least 350:1, and dependent embodiments constrain a central zone thickness range. Additional packaging and electrical safety features are described, including an outer housing or casing and an electrically insulating frame, gasket, or ring contacting peripheral edges of the heat exchanger’s upper and lower wall structures to prevent physical and electrical contact.
Claims Coverage
The independent claims cover an infusion fluid warmer architecture that combines a heat exchanger with a substantially straight fluid channel, integrally formed electrically resistive patterns on a carrier board, and a controller that applies power during a first time period and determines temperature from measured resistance during measurement time periods. The inventive features include the specified straight channel geometry, the specified central-zone width-to-thickness ratio, and controller time-period selective power/measurement operation.
Infusion fluid warmer with DC power control and integrally formed resistive patterns
An infusion fluid warmer comprising a DC power supply input, a first carrier board having a first surface and a second opposing surface with a first integrally formed electrically resistive pattern on the second surface, a heat exchanger with aluminium upper and lower wall structures separated by a fluid channel, and a controller for connecting the DC power supply input to the first integrally formed electrically resistive pattern.
Thermal coupling between resistive pattern and aluminium heat-exchanger upper wall
The controller connects the DC power supply input to the integrally formed electrically resistive pattern so that an outer surface of the upper wall structure is thermally connected to the first resistive pattern, and power is dissipated in the pattern to serve as a heating element during a first time period.
Substantially straight fluid channel along a longitudinal axis
The heat exchanger comprises the aluminium upper wall structure and a lower opposing wall structure separated by a fluid channel extending between fluid inlets and outlets, wherein the fluid channel extends substantially straight along a longitudinal axis of the heat exchanger.
Central-zone width-to-thickness ratio constraint for the fluid channel
A width-to-thickness ratio of a central zone of the fluid channel is at least 50:1 or at least 175:1 or at least 350:1.
Time-period selective power connection for heating in a first time period
The controller connects the DC power supply input to the first or second integrally formed electrically resistive pattern during a first time period to dissipate power in the first or second integrally formed electrically resistive pattern to thereby serve as a heating element during the first time period.
Overall, the claim coverage centers on an infusion fluid warmer that uses integrally formed electrically resistive patterns thermally coupled to an aluminium heat exchanger with a substantially straight fluid channel, with controller time-period control for heating and temperature determination via resistance. Geometry is constrained by a central-zone width-to-thickness ratio, and dependent claims further refine electrical switching and resistance-based temperature determination.
Stated Advantages
Responsive/accurate control based on temperature determination from measured pattern resistance during measurement time periods.
Energy-efficient compact design for the infusion fluid warmer architecture.
Electrical safety via electrically insulating frame, gasket, or ring and electrically insulating/anodized aluminium features to prevent physical and electrical contact.
Documented Applications
Infusion fluid warming using an infusion fluid warmer having a substantially straight fluid channel between fluid inlets and outlets and resistive heating elements thermally coupled to aluminium heat-exchanger walls.
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