Radio frequency fluid warmer
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.
1. 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.
2. The apparatus of claim 1 , wherein the waveguide further includes a pathway for positioning the fluid-carrying tube inside the waveguide.
3. The apparatus of claim 1 , wherein:
the first electromagnetic port is situated in closer proximity to the inlet than to the outlet of the waveguide; and
the second electromagnetic port is situated in closer proximity to the outlet than to the inlet of the waveguide.
4. The apparatus of claim 1 , wherein the radio frequency signals propagate along a length of the waveguide.
5. The apparatus of claim 1 , wherein the inlet is situated substantially adjacent to a sidewall of the waveguide.
6. The apparatus of claim 1 , wherein the waveguide is a rectangular waveguide, and an aspect ratio of the rectangular waveguide is approximately two to one.
7. The apparatus of claim 1 , wherein the waveguide is a rectangular waveguide, and an aspect ratio of the rectangular waveguide is greater than two to one.
8. The apparatus of claim 1 , wherein the waveguide further includes a pathway for positioning the fluid-carrying tube inside the waveguide such that a position of the fluid-carrying tube along a length of the waveguide is adjusted for a uniform energy absorption along the length of the waveguide.
9. The apparatus of claim 1 , wherein the waveguide further includes a pathway for positioning the fluid-carrying tube inside the waveguide such that a position of the fluid-carrying tube is adjusted for a fixed electromagnetic absorption rate along a length of the waveguide.
10. The apparatus of claim 1 , wherein the waveguide is a rectangular waveguide and a position x of the tube along a width of the rectangular waveguide is given by:
P
∝
〈
E
2
〉
=
1
2
μ
T
E
E
y
2
=
1
2
μ
T
E
E
0
2
sin
2
(
π
x
a
)
.
11. The apparatus of claim 1 , wherein the second electromagnetic port is situated in proximity to the outlet port and substantially at the center of a back wall of the waveguide, and wherein a pathway inside the waveguide positions the tube between the inlet and the outlet.
12. The apparatus of claim 1 , wherein the second electromagnetic port is situated in proximity to the outlet port and the outlet port is situated substantially adjacent to a sidewall of the waveguide, and wherein a pathway inside the waveguide positions the tube between the inlet and the outlet.
13. The apparatus of claim 1 , further comprising:
one or more sensors situated in proximity to the inlet and outlet of the waveguide; and
a control module in communication with the one or more sensors, the control module configured to:
monitor a temperature of the fluid inside the fluid-carrying tube based on sensing data of the one or more sensors; and
control a power level of the source of electromagnetic energy in response to the sensing data.
14. The apparatus of claim 1 , wherein the waveguide further includes:
a first shell; and
a second shell configured to register with the first shell, wherein the second shell comprises a structure including a pathway for positioning the tube inside the waveguide.
15. The apparatus of claim 14 , further comprising an electromagnetic choke implemented into mating edges of the first and second shells to prevent electromagnetic leakage.
16. The apparatus of claim 14 , wherein the structure that forms the pathway for positioning the tube inside the waveguide comprises a low loss material such as a foam structure.
17. 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.
18. The apparatus of claim 17 , further comprising a circuit board including one or more sensors situated in proximity to the inlet and the outlet of the rectangular waveguide.
19. The apparatus of claim 18 , wherein the circuit board is configured, locally by a controller or remotely, to:
execute failsafe operations of self-administered procedures;
enable a custom remote programming of a warmer operating mode;
execute one or more executable instructions concerning patient-specific programming; or
execute one or more executable instructions concerning patient-specific record keeping.
20. 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.