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 first shell;
a waveguide including first and second electromagnetic ports, an inlet for receiving a fluid, and an outlet for dispensing the fluid;
a tube for routing the fluid inside the waveguide between the inlet and the outlet during operation of the apparatus;
a source of electromagnetic energy coupled to the first electromagnetic port;
a termination coupled to the second electromagnetic port for preserving a matched waveguide condition; 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.
2. 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.
3. The apparatus of claim 1 , wherein the waveguide further includes a pathway for positioning the tube inside the waveguide.
4. The apparatus of claim 1 , wherein the radio frequency signals are applied along a length of the waveguide.
5. The apparatus of claim 1 , wherein the waveguide is a rectangular waveguide and the inlet is situated substantially at a sidewall of the rectangular waveguide.
6. The apparatus of claim 5 , wherein a position x of the tube along a width of the rectangular waveguide is given by:
P
∝
<
E
2
>=
1
2
μ
TE
E
y
2
=
1
2
μ
TE
E
0
2
sin
2
(
π
x
a
)
.
7. The apparatus of claim 5 , wherein the second electromagnetic port is situated in proximity to the outlet 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.
8. 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 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.
9. The apparatus of claim 1 , further comprising an electromagnetic choke implemented into mating edges of the first and second shells to prevent electromagnetic leakage.
10. A radio frequency fluid warmer apparatus, comprising:
a first shell;
a waveguide 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 waveguide for routing the fluid tube between the inlet and the outlet;
a radio frequency generator coupled to the first electromagnetic port;
a termination coupled to the second electromagnetic port for preserving a matched waveguide condition; and
a second shell configured to register with the first shell, wherein the second shell comprises a structure that forms the pathway for positioning the tube inside the waveguide.
11. The apparatus of claim 10 , wherein the waveguide is a rectangular waveguide and the inlet is situated substantially at a sidewall of the rectangular waveguide.
12. The apparatus of claim 11 , wherein a position x of the tube along a width of the rectangular waveguide is given by:
P
∝
<
E
2
>=
1
2
μ
TE
E
y
2
=
1
2
μ
TE
E
0
2
sin
2
(
π
x
a
)
.
13. The apparatus of claim 10 , 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 radio frequency generator and the one or more sensors, the control module configured to:
monitor a temperature of the fluid inside the tube based on sensing data from the one or more sensors; and
control an output of the radio frequency generator in response to the sensing data.
14. The apparatus of claim 10 , wherein the structure that forms the pathway for positioning the tube inside the waveguide comprises a foam structure.
15. A system for warming intravenous fluids using radio frequency signals, comprising:
a rectangular waveguide housed in a first compartment of an enclosure, the rectangular waveguide including first and second electromagnetic ports, an inlet situated substantially at a sidewall of the rectangular waveguide for receiving a fluid, and an outlet for dispensing the fluid;
a control module housed in a second compartment of the enclosure and configured to:
generate radio frequency signals from an energy source; and
apply the radio frequency signals to the first electromagnetic port;
a tube for routing the fluid inside the rectangular waveguide between the inlet and the outlet of the rectangular waveguide during operation of the system; and
a termination coupled to the second electromagnetic port for preserving a matched waveguide condition.
16. The apparatus of claim 15 , wherein the rectangular waveguide further includes a pathway for positioning the tube inside the waveguide.
17. The apparatus of claim 15 , wherein a position x of the tube along a width of the rectangular waveguide is given by:
P
∝
<
E
2
>=
1
2
μ
TE
E
y
2
=
1
2
μ
TE
E
0
2
sin
2
(
π
x
a
)
.
18. The apparatus of claim 16 , wherein the radio frequency signals are applied along a length of the rectangular waveguide.