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Publication Number
US-10952290-B1
Publication Date
2021-03-16
Expiration Date
Abstract
The present invention is generally a radio frequency apparatus for warming fluids such as IV fluids. In exemplary embodiments, a uniform warming of fluids is achieved by exposing a fluid-carrying tube to Radio Frequency (RF) energy. The RF energy may be supplied by an RF generator, which is coupled to a waveguide. The waveguide typically includes an inlet into which a fluid tube may be introduced. Inside the waveguide, a pathway may be formed wherein the fluid tube may rest in a predetermined position. In exemplary embodiments, the pathway guides the positioning of the tube along a transmission-line length of the waveguide, in a manner such that the tube gradually approaches an electromagnetic field inside the waveguide and exits at a second terminal end of the waveguide. Having absorbed energy supplied from the RF generator, the fluid inside the tube exits the apparatus warmed to a desired temperature.
Core Innovation
The invention relates to a radio frequency (RF) in-line fluid warmer apparatus for receiving a fluid-carrying tube that traverses a waveguide. The apparatus includes a waveguide with first and second electromagnetic ports, an inlet, and an outlet, with the fluid-carrying tube routed inside the waveguide using a shaped pathway. The RF generator is coupled to the first electromagnetic port, and RF signals propagate along the length of the waveguide while the warmed fluid flows through the tube along the waveguide length.
A resistive termination is coupled to the second electromagnetic port to preserve a matched waveguide condition by collecting an unabsorbed portion of input RF power and dumping the unabsorbed portion into a match load. The waveguide and the tube pathway are configured to control field interaction along the transmission-line length. This arrangement is presented as enabling uniform heating and reducing hotspot formation by using a travelling-wave approach as compared to standing-wave hotspot effects.
The disclosed implementation further includes temperature sensing at the inlet and outlet and a controller to monitor fluid temperature and control RF power level based on the sensed temperature. The description also characterizes a cartridge-free/sterile-continuity implementation using a clam-shell waveguide housing, including low-loss foam pathway features and RF chokes to address electromagnetic behavior. Compact reduced-height waveguide implementation is described with integrated printed circuit board, sensors, controller functions including failsafe/self-procedure execution, and patient-specific programming and patient-specific record keeping.
Claims Coverage
The independent claims are clm-00001, clm-00017, and clm-00020. Across these claims, the coverage focuses on three inventive features: a waveguide-based RF fluid warming apparatus with electromagnetic ports and matched termination, tube routing and pathway configuration relative to the waveguide length and electromagnetic dissipation, and RF signal propagation along the waveguide length with fluid-flow direction aligned to that length.
Waveguide with electromagnetic ports and fluid-tube traversal with matched resistive termination
A radio frequency fluid warmer apparatus comprising a waveguide including first and second electromagnetic ports, an inlet, and an outlet for receiving a fluid-carrying tube that traverses the waveguide; a radio frequency generator coupled to the first electromagnetic port; and a resistive termination coupled to the second electromagnetic port for preserving a matched waveguide condition and adapted to collect an unabsorbed portion of input power and dump the unabsorbed portion of input power in a match load.
Rectangular waveguide with pathway-adjusted tube position for fixed electromagnetic dissipation
A radio frequency fluid warmer apparatus comprising a rectangular waveguide wherein an aspect ratio of the rectangular waveguide is greater than two to one including first and second electromagnetic ports, an inlet, and an outlet for receiving a fluid tube that traverses the waveguide; a pathway situated inside the rectangular waveguide for routing the fluid tube between the inlet and the outlet, wherein the pathway is configured to position the fluid tube such that a position of the fluid tube is adjusted for a fixed electromagnetic dissipation caused by fluid-absorption along a length of the waveguide; a radio frequency generator coupled to the first electromagnetic port; and a termination coupled to the second electromagnetic port for preserving a matched waveguide condition.
Fluid-flow along waveguide length with RF propagation and matched resistive termination
A radio frequency fluid warmer apparatus comprising a waveguide including first and second electromagnetic ports, an inlet, an outlet for receiving a fluid-carrying tube that traverses the waveguide, and a pathway for positioning the fluid-carrying tube inside the waveguide such that a direction of a fluid flow of the fluid-carrying tube is along a length of the waveguide; a radio frequency generator coupled to the first electromagnetic port; and a resistive termination coupled to the second electromagnetic port for preserving a matched waveguide condition, wherein radio frequency signals propagate along the length of the waveguide.
Taken together, the independent claim coverage defines an RF fluid warmer built around an RF waveguide with inlet and outlet for a traversing fluid tube, electromagnetic ports driven by an RF generator, and a resistive termination that preserves a matched waveguide condition while collecting and dumping unabsorbed input power into a match load. Further distinctions include using a rectangular waveguide aspect ratio and a pathway-configured tube position adjusted for fixed electromagnetic dissipation along the waveguide length.
Stated Advantages
Enables uniform heating by controlling field interaction along the transmission-line length while avoiding hotspot formation associated with standing-wave behavior.
Preserves a matched waveguide condition by collecting unabsorbed input power and dumping the unabsorbed portion into a match load.
Monitors fluid temperature at the inlet and outlet and controls RF power level based on sensed temperature.
Supports a cartridge-free/sterile-continuity implementation via a clam-shell waveguide housing with low-loss foam pathway and RF chokes.
Documented Applications
Warming of therapeutic fluids including IV fluids, blood products, peritoneal dialysis dialysate, and CRRT replacement fluids in an in-line configuration using an RF fluid warmer apparatus.
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