Radio frequency fluid warmer and method
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 method performed by radio frequency fluid warmer system, comprising the steps of:
controlling a power level of a radio frequency generator coupled to a first electromagnetic port of a waveguide, wherein the waveguide includes a resistive termination coupled to a second electromagnetic port of the waveguide for preserving a matched waveguide condition, and wherein the waveguide is adapted to receive a fluid-carrying tube positioned between an inlet and an outlet of the waveguide;
receiving sensing data from one or more sensors situated in proximity to the inlet or the outlet of the waveguide; and
monitoring a parameter of a fluid inside the fluid-carrying tube based on sensing data from the one or more sensors.
2. The method of claim 1 , wherein controlling the power level of the radio frequency generator, comprises:
adjusting the power level of the radio frequency generator based on the sensing data from the one or more sensors.
3. The method of claim 1 , wherein controlling the power level of the radio frequency generator, comprises:
adjusting the power level of the radio frequency generator to bring a fluid temperature at the inlet of the waveguide (T 0 ) to a value less than a target temperature (T_target×N (%)).
4. The method of claim 1 , wherein controlling the power level of the radio frequency generator, comprises:
adjusting the power level of the radio frequency generator to bring a fluid temperature at the inlet of the waveguide (T 0 ) to at least a near equilibrium with a fluid temperature at the outlet of the waveguide (T 1 ).
5. The method of claim 1 , further comprising:
adjusting a pulse-wave-modulation (PWM) duty-cycle based on the sensing data of the one or more sensors.
6. The method of claim 1 , further comprising:
determining a waiting period based on a system response time.
7. The method of claim 1 , wherein controlling the power level of the radio frequency generator, comprises:
adjusting the power level of the radio frequency generator to bring a fluid temperature at the outlet of the waveguide (T 1 ) within a temperature range of a programmable upper error limit (T_target+upper error limit) and a programmable lower error limit T_target−lower error limit such that:
T 1 ≥(T_target−lower error limit); and
T 1 ≤(T_target+upper error limit).
8. The method of claim 1 , further comprising:
triggering a shut-off sequence in response to determining a fault condition based on the sensing data of the one or more sensors.
9. The method of claim 8 , wherein the shut-off sequence includes one or more of:
shutting off a fluid flow by activating a valve in fluid communication with the fluid-carrying tube;
shutting off a power supply to the radio frequency generator;
activating an audible indicator; or
activating a visual indicator.
10. The method of claim 1 , wherein the one or more parameters include:
a fluid temperature at the inlet of the waveguide;
a fluid temperature at the outlet of the waveguide; or
a flow speed of the fluid inside the fluid-carrying tube.