Various types of fluids, such as saline, are routinely introduced in some format into a patient, such as a human or an animal, as part of a medical procedure or for various medical reasons. Because these fluids are being introduced for example into the patient's bloodstream, the fluid needs to be provided in a sterile environment, and must not be contaminated as part of the process of transferring the fluid from the fluid's original packaging or container to the patient. In addition, to decrease any level of discomfort or chilling of the patient as a result of the introduction of the fluid into the patient's bloodstream, the fluid is often warmed, for example using a heating device, to a temperature above a normal room temperature and to a temperature that more closely corresponds to the body temperature of the patient. The heating of the fluid must be performed in a manner that does not cause or contribute to any contamination of the fluid prior to or following the introduction of the fluid into the patient.
Aspects/Embodiments of the disclosure may be better understood by referencing the accompanying drawings.
The drawings are provided for the purpose of illustrating example embodiments. The scope of the claims and of the disclosure are not necessarily limited to the systems, apparatus, methods, or techniques, or any arrangements thereof, as illustrated in these figures. In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same or coordinated reference numerals. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness.
The description that follows includes example systems, methods, techniques, and program flows that illustrate and describe various embodiments of a non-contact radio-frequency (RF) heating element and a control unit for operating a non-contact RF heating element. However, it is understood that this disclosure may be practiced without these specific details. For instance, this disclosure refers to non-contact RF heating applied to a flow-through non-contact RF heating element for use in medical procedures involving the heating of fluid for introduction into a patient in illustrative examples. However, aspects of this disclosure may be applied to other examples of systems used to heat a fluid, both in a flow-through and in static reservoir arrangements. In certain examples illustrated and described throughout the disclosure, well-known instruction instances, protocols, structures and techniques have not necessarily been shown in detail in order not to obfuscate the description.
In system 100, a dielectric barrier 106 at least partially surrounds the fluid passageway 108, and isolates the fluid passageway from electrodes 102, 104 so that the fluid passing through fluid passageway 108 is not brought into contact with the electrodes. Dielectric barrier 106 may be formed from an insulating material, such as but not limited to a plastic material such as polyimide. In various embodiments, dielectric barrier 106 may be part of the heating element body, and may be configured as a disposable sterile insert, such as a catheter, that is inserted within and extends through fluid passageway 108 to provide a sterile environment for the fluid to flow through while flowing through fluid passageway. In some embodiments, dielectric barrier 106 is part of the sterile environment used in contact with and to provide a conduit for the flow of fluid through the fluid passageway 108, and is removable and disposable after use in a fluid warming procedure utilizing system 100. A heating element body, such as body 110, may be configured to hold the electrodes 102, 104 in a position spaced apart from one another and proximate to fluid passageway 108. Electrode 102 and/or electrode 104 may be partially or wholly embedded within body 110 in some embodiments in order to maintain the proper positioning of the electrodes relative to each other and to dielectric barrier 106 and fluid passageway 108.
As further described below, system 100 may be configured to provide and control electrical energy that is output from the electrical power source 101 and provided to electrodes 102, 104, in order to provide a controlled heating of the fluid flowing through passageway 108, such as a fluid intended for introduction into a patient, while the fluid flows through or is present within the fluid passageway. System 100 may be further configured to warm the flow of fluid through fluid passageway 108 while maintaining a sterile environment with respect to any of the passageways and fluid conduits that come into direct contact with the fluid being heated subsequent to the introduction into the patient.
Element 250 includes a heating element body 251 (hereinafter “body 251”) having a first end coupled to a fluid input conduit 253 and a second end that is opposite the first end, the second end coupled to a fluid output conduit 254. A hollow passageway 252 extends from the first end to the second end of the body 251, forming a fluid passageway to transport a flow of fluid entering the first end of body 251 as provided by the fluid input conduit 253 to the second end of the body and to the outlet provided by fluid output conduit 254. Element 250 further includes one or more sets of electrodes positioned within body 251, the electrodes positioned proximate to passageway 252, and sealed from passageway 252, for example by a portion of the body 251, so that the electrodes will not come into contact with the fluid flowing through the passageway. Embodiments of passageway 252 are not limited to being formed as a single straight passageway, and in various embodiments may include a set of parallel passageways, or a single passageway that winds along, for example in a serpentine path or other non-linear path, through the body 251 of element 250.
As illustrated in
Electrical energy provided by control unit 201 to electrode 255 and return electrode 256 may establish an electromagnetic field in an area between the electrodes, and thus be imposed onto a fluid included within passageway 252. The field established between the electrodes may then induce non-contact RF heating of the fluid included in the passageway. By controlling the amount and format to the electrical energy provided to electrode 255 and return electrode 256, control unit 201 may be configured to controllably heat a flow of fluid passing through passageway 252 of element 250. In various embodiments, the fluid to be heated is saline, or a saline solution, which is being provided as a non-limiting example of a fluid that may be introduced into a patient after passing through element 250 and being heated to a desired temperature before being introduced into the patient. Heating of the saline may reduce patient discomfort related to the introduction of the heated fluid introduced into the patient at a body temperature or a near body temperature as opposed to a lower temperature, such as a room temperature where the saline fluid is initially stored and introduced into system 200. In addition, because the saline solution is being provided to the patient and in a medical setting, it is important that the heating of the saline be accomplished without contamination of the saline as part of the heating process. As show in
In various embodiments, element 250 of system 200 is configured to couple to a fluid source 260, wherein fluid source 260 may include a pump or other mechanism to produce a flow of fluid, such as a flow of saline, to fluid input conduit 253. Fluid input conduit 253 is coupled to the first end of body 251, and is in fluid communication with passageway 252. A flow of fluid, such as saline provided by fluid source 260, may flow through passageway 252 and between electrode 255 and return electrode 256, and exit body 251 through fluid output conduit 254. As the fluid flows through passageway 252, electrical energy under the control of control unit 201 may be provided to electrode 255 and return electrode 256, and produce non-contact RF heating of the fluid within passageway 252. One or more sensors, such as temperature sensor 257, may be positioned proximate to passageway 252, and may be configured to sense the temperature of the flow of fluid as the fluid passes through and exits passageway 252. The sensor(s) generate one or more sensor output signals that are indicative of the sensed temperature of the fluid passing through and/or exiting passageway 252, and provide the output signal(s) to a sensor input 218 of control unit 201, for example though sensor input lines 258. In some embodiments, sensor input 218 may include or be coupled to a multiplexer 219 configured to multiplex a plurality of input signals from multiple sensors into control circuitry 210, for example using some predefined sampling rate. Control unit 201 may be configured to receive and process the sensor input signal(s) related to temperature of the fluid, and to further control the output of electrical energy being provided to electrode 255 and return electrode 256 by controlling the electrical output being provided to electrode output terminal 206 and electrode return terminal 207 of the control unit.
In addition to temperature sensing, one or more other types of sensors, such as one or more flow sensors illustratively represented by sensor 259, and one or more ambient temperature sensors illustratively represented by sensor 264, may be included in system 200 to provide additional feedback to control unit 201. In various embodiments, flow sensor 259 is configured to determine a flow rate or a flow volume passing by the sensor, and provide an output signal to control unit 201 indicative of the flow rate or the volume of flow passing by the sensor. This flow rate/flow volume information may be received by control unit 201, and further incorporated into the control of the electrical energy being provide by the control unit to element 250 in order to maintain the temperature control of the flow of fluid passing through element 250 in a desired manner.
In various embodiments, ambient temperature sensor 264 is configured to determine an ambient temperature in one or more areas outside element 250, such as an ambient temperature of the area where the fluid source 260 is located, and/or an ambient temperature in the area where the fluid output conduit 254 passes between the element 250 and the point where the fluid is introduced into a patient. Ambient temperature sensor 264 may be configured to generate and to provide an output signal to control unit 201 indicative of the ambient temperature in one or more areas located outside of element 250. This ambient temperature information may be received by control unit 201, and further incorporated into the control of the electrical energy being provide by the control unit to element 250 to maintain the temperature control of the flow fluid passing through element 250 in a desired manner.
As shown in
As illustrated for system 200, input power processing circuitry 203 is coupled to at least one electrical power input source (not specifically shown in
Regardless of the power input configuration, input power processing circuitry 203 may be configured to perform conditioning of the incoming electrical power to provide electrical power that is coupled to the electrical components and devices included in control unit 201, including the electrical waveform generator 204, control circuitry 210, and power-delivery circuitry 205. For the sake of clarity and simplicity, actual lines showing the specific power connections between the electrical components and devices of control unit 201 and the input power processing circuitry 203 may not be illustrated in
In various embodiments, all or various combinations of these power conditioning processes may be performed by input power processing circuitry 203 on the power being provided by the input power processing circuitry to the electrical components and devices included in control unit 201. In one embodiment, the electrical power input provided to input power processing circuitry includes 120 VAC 60 Hz electrical power, and the output power provided by the input power processing circuitry 203 to the power-delivery circuitry 205 includes a rectified waveform. As further described below, an intermediate electrical waveform generated by the electrical waveform generator 204 and provided to the power-delivery circuitry 205 is used to switch ON and OFF, and otherwise control the coupling of the electrical power provided by the input power processing circuitry 203 to the electrodes of the element 250 through the electrical devices, such as switching devices, included in the power-delivery circuitry.
As shown in
The type of circuitry utilized by RF source 204A to generate the electrical waveform is not limited to any particular type of circuitry or to any particular technique for generating an electrical waveform. In some embodiments, RF source 204A includes one or more high speed timers configured to generate an varying voltage output signal. In various embodiments, RF source 204A includes a voltage controlled oscillator, or some other type of oscillator, configured to generate a varying voltage output signal. Other types of circuitry and techniques may be utilized as part of RF source 204A to generate the electrical waveform having a varying voltage output, and are contemplated for use as embodiment(s) of the RF source included in control unit 201.
As shown in
In addition to or instead of controlling the frequency of the electrical waveform provided by RF source 204A, modulator 204B may be configured to variably control a maximum voltage level or a voltage range, such as peak-to-peak voltage, of the electrical waveform received from the RF source. For example, modulator 204B may variably increase or decrease the amount of voltage variation, including varying a maximum voltage level or varying a voltage range (peak-to-peak voltage) of the electrical waveform received by the modulator from RF source 204A. The variations in the voltage level(s) generated by modulator 204B may then be provided as the intermediate electrical waveform that is output from the modulator. Controlling variations in the voltage levels of the intermediate electrical waveform output by modulator may be used to control the overall amount of electrical energy that is to be delivered to the electrodes of a non-contact RF heating element, such as element 250, that is being regulated by the intermediate electrical waveform as further described below.
In some embodiments, modulator 204B may be configured to modulate the electrical waveform received from the RF source 204A by varying the frequency of the electrical waveform to generate the intermediate electrical waveform that is then provided as an output from the modulator. Controlling variations in the frequency of the intermediate electrical waveform that is being output by modulator may be used to control the overall amount of electrical energy that is delivered to the electrodes of an non-contact RF heating element, such as element 250, that is being regulated by the intermediate electrical waveform as further described below.
As shown in
The switching devices included in the power-delivery circuitry 205 are also configured to be controllably switched OFF, and thus to disconnect the electrical power being provided by power lines 220 to the power-delivery circuitry from the outputs of the power-delivery circuitry coupled to electrode output terminal 206 (OUT 1) and the electrode return terminal 207. In various embodiments, during the periods of time when the switching devices are switched ON, the switching devices included in the power-delivery circuitry 205 may be further controlled by the intermediate electrical waveform received from the electrical waveform generator 204 to vary for example the voltage level being provided at the electrode output terminal coupled to the switching device(s) in order to provide a varying voltage output waveform having variations corresponding to the variations of the intermediate electrical waveform to the electrodes of element 250. As further described below, the various parameters of the intermediate electrical waveform generated by the electrical waveform generator 204 may be controlled by input signals provided to the electrical waveform generator by control circuitry 210. In various embodiments, electrical waveform outputs provided to the electrodes of element 250 as an output from the power-delivery circuitry 205 and as controlled by the intermediate electrical waveform generated by electrical waveform generator 204 may be configured to produce non-contact radio-frequency heating of a fluid flowing through passageway 252 of the element.
As shown in
In various embodiments, control circuitry 210 may monitor, using one or more electrical sensors including in the input power processing circuitry 203 and/or the power-delivery circuitry 205, an impedance level of the electrical circuit provided across electrode 255 and return electrode 256. For example, the type of fluid flowing through passageway 252 may affect the impedance value of the electrical circuit that includes the area between electrode 255 and return electrode 256. By way of example, a fluid such as saline will present a different level of electrical impedance for an electromagnetic field established in the fluid as compared to water. In various embodiments, control circuitry 210 may be configured to measure an impedance that is presented in the electrical circuitry including the area between electrode 255 and return electrode 256, and to adjust the control parameters applied to the electrical waveform generator 204 and/or to the power-delivery circuitry 205 based on the sensed impedance measurements. In various embodiments, control circuitry 210 may be configured to estimate a temperature of a fluid flowing through or contained within passageway 252 of element 250 based on measurement(s) of the impedance of the circuit that includes the fluid present between electrode 255 and return electrode 256. By way of example, a measurement of the voltage, current, and phase applied to the electrodes 255, 256 may be made, and an impedance value (real and imaginary: R+jX), is determined based on these measured values. The determined impedance value is then comparted to values either in a look-up table, or applied to an equation in order to determined temperature value corresponding to the impedance value. In some embodiments, power and other variables, such as input voltage, may be used to determine a value for liquid conductivity, and then correlated to a temperature value of the liquid.
Control circuitry 210 may utilize one or more techniques to control the overall level of electrical energy provided to the electrodes of a non-contact radio-frequency heating element, such as element 250, and thus control the heating of a fluid flowing through the heating element. In various embodiments, control circuitry 210 may provide one or more control signals to input power processing circuitry 203. These control signals may allow the control circuitry to modify one or more parameters of the power that is to be or is being provided by the input power processing circuitry to the power-delivery circuitry 205. In various embodiments, control circuitry 210 may provide one or more control signals to electrical waveform generator 204 configured to control and/or vary the frequency of the intermediate electrical waveform being provided as an output from the electrical waveform generator. Varying the frequency of the electrical waveform generator's intermediate electrical waveform may change the overall impedance of the circuit that includes a fluid flowing past and/or positioned between electrodes of a non-contact radio-frequency heating element, and thus control the overall heating of the fluid. In various embodiments, control circuitry 210 may provide one or more control signals to electrical waveform generator 204 that are configured to control and/or vary one or more of voltage levels, such as peak voltage and/or peak-to-peak voltage, of the electrical output waveform provided as an output from the power-delivery circuitry 205. Varying one or more voltage levels of the intermediate electrical waveform being provided as an output from the electrical waveform generator 204 may change the overall level of electrical power being delivered by the power-delivery circuitry 205 to the electrodes of a non-contact radio-frequency heating element, such as element 250, and thus control the overall heating of the fluid passing through the non-contact radio-frequency heating element.
In various embodiments, control circuitry 210 may provide one or more control signals to electrical waveform generator 204, for example to modulator 204B, that are configured to control and/or generate a pulsed output of the intermediate electrical waveform provided as an output from electrical waveform generator 204 to the power-delivery circuitry 205, and thus control a duty cycle for the application of electrical power to the electrodes of a non-contact radio-frequency heating element, such as element 250. Controlling a duty cycle of the electrical power being provided as an output from the power-delivery circuitry 205 may change the overall level of electrical power being delivered to the electrodes of a non-contact radio-frequency heating element, and thus control the overall heating of the fluid passing through the non-contact radio-frequency heating element.
Various embodiments of control unit 201 include a user interface 214 communicatively coupled to control circuitry 210. User interface 214 may be configured to allow electrical communications, for example but not limited to communication utilizing a RS-232 format, between control circuitry 210 and one or more other computer systems, such as computer system 265 as illustrated in
In various embodiments, control unit 201 may include a temperature output 216 that is electrically coupled to control circuitry 210. Temperature output 216 may provide an output signal, such as a voltage output, that is indicative of a current temperature value for a fluid that is being heated by or at least flowing through the non-contact radio-frequency heating element coupled to control unit 201. The temperature output signal may in some embodiments be provided to a display device configured to visually display a value corresponding to the temperature indicated by the signal provided at the temperature output 216.
Control unit 201 may provide various features and perform various functions related to safety and regulation of a non-contact radio-frequency heating system such as system 200. For example, various types of shielding may be provided to limit or eliminate electromagnetic radiation associated with the higher frequencies that may be generated by and transmitted through the system. In various embodiments, certain fault conditions may be monitored for, and when detected may result in a shutdown and/or a power down of one or more portions of the control unit. For example, an overvoltage and/or an over current condition occurring in the power input power processing circuitry, 203, electrical waveform generator 204, and/or power-delivery circuitry 205 may be monitored for, and if any voltage or current levels exceed acceptable levels, one or all of these portions of the control unit 201 may be powered down. In various embodiments, the temperature of one or more switching devices, such as MOSFETs, that may be included in power-delivery circuitry 205 may be monitored, and if these temperature(s) exceed acceptable limits, the power-delivery circuitry 205 may be powered down. In various embodiments, a parameter related to a maximum fluid temperature sensed by one or more temperature sensors sensing temperatures of the fluid at or passing through the non-contact radio-frequency heating element coupled to the control unit may be monitored, and if the fluid temperature(s) exceeds any threshold level(s) set for fluid temperature, the control unit may shut down the electrical waveform generator and/or power-delivery circuitry of the control unit so that the electrical output waveform is disconnected from the electrode output terminal(s) of the control unit and is no longer being applied to the electrodes of the non-contact radio-frequency heating element. In various embodiments, a flow level or volume of fluid flow passing through the non-contact radio-frequency heating element is monitored, and if no flow is detected, or for example a minimum level of fluid flow is not detected, the control unit may be configured to stop providing electrical energy to the electrodes of the non-contact radio-frequency heating element, and thus cease any further heating of the fluid until and/or unless a fluid flow is detected, or the minimum level of fluid flow is re-established through the non-contact radio-frequency heating element.
In various embodiments the control circuitry 210 performs the monitoring and alarm function, and controls output signals to the electrical waveform generator 204 and/or the power-delivery circuitry 205 to power down or shut down portions of the control unit when an unacceptable, fault, or alarm condition is detected. In various embodiments, other devices, such as fuses and/or circuit breaker, which may or may not be controlled by the control circuitry 210, may provide protection, such as protection against electrical overloads within the control unit 201 and/or associated with the electrical power being provided to the non-contact radio-frequency heating element by the control unit and/or to the control unit from any electrical power input sources coupled to lines 202.
The overall wattage level of electrical energy provided by control unit 201 to a RF heating element, such as element 250, is not limited to any particular wattage, and in various embodiments is configured and controlled based on the particular application, such as the type of fluid being processed, the amount of heating of the fluid that is required, and/or the configuration of the RF heating element itself. In various embodiments, a control unit, such as control unit 250, is configured to provide an overall wattage level in a range of 0 to 500 watts of electrical power in a controlled manner to a RE heating element. Embodiments may include higher wattage levels for example up to and including 2000 watts or more, again depending on the application. In various arrangements, the application of the electrical energy to the fluid as part of the RF heating process may generate bubbles, such as gas bubbles, in the fluid. The formation of bubbles may create issues, for example in medical applications involving a patient, and/or may change the impedance across the electrodes of the RF heating element, which in turn may affect the regulation of the RF heating process being performed by the control unit and the RF heating element. In various embodiments, operations utilizing the RF heating element may include positioning the exit end of the element in a vertical or upward orientation to: 1) allow for all bubbles to exit the tubing, 2) for preventing any new bubbles from getting trapped, 3) and/or allow any generated gas to escape. In various embodiments, one or more bubble sensors may be incorporated into a RF heating system, such as system 200, to detect the presence of gas bubbles in the fluid being heated, and to provide an output signal to the control unit 201 indicative of the presence or absence of bubbles that may be detected in the fluid. An embodiment of a bubble sensor may comprise a light source, such as but not limited to a laser light source, and a photo detector, such as but not limited to a photodiode, configured to detect the light provided by the light source. The bubble detector may be configured to provide an output signal that is indicative of the presence or absence of bubbles in the fluid. In various embodiments, the bubble sensor may be built into the RF heating element, and/or may be incorporated into the fluid output conduit, such as fluid output conduit 254 as shown in
As shown in
Following time T3, a subsequent time period 310 may include waveform 301 switched to an ON state, extending to time T4 as represented by arrow 310, wherein at time T4 waveform 301 is switched back to the OFF state for a time period represented by arrow 311 extending from time T4 to time T5. The time periods 310 and 311 represent another and subsequent ON/OFF switching cycle of waveform 301 having a duty cycle and an overall period that may be adjusted to control the overall amount of electrical power provided during this subsequent cycling of waveform 301. Additional switching cycles, as represented by the partially illustrated time period of at arrow 312, may follow after time T5 and may include variable time periods and/or variable duty cycles as described above for the previous ON/OFF switching cycles of waveform 301.
The ON/OFF switching of waveform 301 may represent a switching of an electrical power output from an electrical waveform generator (e.g., electrical waveform generator 204,
As shown in
As further illustrated in
As shown in
In various embodiments, the time period during which waveform 361 is provided as having a first frequency illustrated by arrow 365 may be varied, as illustratively indicated by double arrows 366, and/or the time period during which waveform 361 is provided as having a second frequency different from the first frequency, as illustrated by arrow 367 may be varied, as illustratively indicated by double arrows 368. In addition to varying frequency of waveform 361 over different and subsequent time periods, waveform 361 may be switched ON and OFF in a manner similar to that described above for waveform 301 and graph 300. In the alternative or in addition to switching the waveform 361 ON and OFF, the overall peak-to-peak volte of waveform 361 may be varied in a same or similar manner as described above with respect to graph 330 and waveform 331.
As shown in
In various embodiments, each of electrodes 411, 412, 413, and 414 is electrically isolated from one another, and positioned above and proximate to passageway 252 of non-contact radio-frequency heating element 250. A return electrode 420 is electrically isolated from each of the electrodes 411, 412, 413, and 414, and is positioned below passageway 252 on an opposite side of the passageway relative to electrodes 411, 412, 413, and 414. As shown in
In various embodiments, electrode conductor wiring 422 may include shielding coupled to return electrode 420, and to electrode return terminal 207 of control unit 201, wherein separate sets of wiring may be utilized to couple and/or shield each individual electrode 411, 412, 413, and 414 along with a respective return conductors for coupling the respective electrode and return electrode 420 to control unit 201. In various embodiments, instead of being formed as a single electrode, return electrode 420 may comprise individual electrodes (not specifically shown in
In various embodiments, electrodes 411, 412, 413, and 414, along with return electrode 420, are generally formed having a planar flat shape. However, embodiments of the electrodes and the return electrode or return electrodes are not limited to having a planar flat shape, and may for example have a curved arch-shape the extends at least partially around the longitudinal axis 262 at some radial distance from the longitudinal axis while remaining electrically isolated from direct contact with all other electrodes included in the element 250.
In various embodiments, control unit 201 may be configured to individually control an electrical output waveform provided to each of the electrode output terminals, 401, 402, 403, and 404, thus providing individually controlled outputs to each of the electrodes 411, 412, 413, and 414, respectively. In various embodiments, control unit 201 may operate all of the electrode output terminals 401 at the same time with respect to a switched ON and OFF state for application of an electrical output waveforms to the electrodes. In various embodiments, control unit 201 or may operate these ON and OFF states to individually control the output of an electrical output waveform to the respective electrode output terminals, and thus to the electrodes of the element 250 on an individual basis, wherein one or more of the electrode output terminals may be switched to an OFF state while other ones of the electrode output terminals are switched to an ON state. In various embodiments, an added number of temperature sensors, for example five temperature sensors as illustrated in
In various embodiments, different electrical output waveforms, such as but not limited to the electrical output waveforms described above with respect to
The windings forming inductive coils 281, 282, 283, and 284 are not limited to any particular type of winding, or to any particular number of turns per used to form each coil, or to any particular type of material used to form the inductive coils. In some embodiments, each of inductive coils 281, 282, 283, and 284 comprises a same type of electrical conductor, such as a conductive metal such as copper, aluminum, silver, or gold, which may be used to form each winding, and a same number of turns of the electrical conductor. However, embodiments of the element 270 are not limited to having four coils in number, and may have more or less than four coils, including having just a single (one) coil. Further, embodiments of element 270 are not limited to having each of a plurality of coils included in the element comprising a same type of coil winding. For example, one or more of a plurality of coils included in element 270 may include more or less turns of winding of the electrical conductor used to form the inductive coil, and/or may be formed from a different electrical conductor, for example a different gauge of wire or other conductive element used to form the inductive coil(s).
In operation, control unit 201 may be configured to provide one or more electrical output waveform(s) to inductive coils 281, 282, 283, and 284 in order to generate an electromagnetic field in the area surrounding each inductive coil, including within the area surrounding each inductive coil included within passageway 278 of inner tube 273. The electromagnetic field(s) generated by inductive coils 281, 282, 283, and 284 may be configured produce heating for fluid that is flowing through or contained within the passageway 278. In various embodiments, control unit 201 applied a same electrical output waveform to each of inductive coils 281, 282, 283, and 284 at or over a same time period, including applying a pulsed electrical output waveform to each of the inductive coils 281, 282, 283, and 284 at a same period and same phase relative to the pulses of the electrical output waveform. However, embodiments may include control unit 201 providing different electrical waveform(s) to one or more of the inductive coils 281, 282, 283, and 284 at a same or at different times, wherein various combinations of the inductive coils 281, 282, 283, and 284 may be energized and de-energized at different time relative to one another and energized using different electrical output waveforms at a same or different time relative to the electrical waveform(s) being applied to energize other ones of the inductive coil. By varying and controlling the electrical waveform(s) used to energize the inductive coils 281, 282, 283, and 284, and/or the timing of the energization of each of the inductive coils 281, 282, 283, and 284, either individually or together is some combination, the heating of the fluid that is flowing through or contained within passageway 278 may be controlled.
Embodiments utilizing element 270 may be configured and operated to provide any of the features and to perform any of the functions related to heating, sterilization, or other processing of fluid as described throughout this disclosure, and any equivalents thereof. For example, as shown in
Driver/switching circuitry 605 may be an example embodiment of the power-delivery circuitry 205 (
Microprocessor 610 as illustrated in
Various features and functions of the embodiment of a non-contact radio-frequency heating control unit have been described additional features and function that may be provided by and included as part of the embodiments of the non-contact radio-frequency heating control units as described throughout this disclosure are further described below.
Embodiment of the non-contact radio-frequency heating may be performed using frequencies in a range of 10 kHz to 30 MHz, or as high as 100 MHz, or as high as 300 GHz, which may allow a volume of liquid to be heated faster with a lower surface area to volume ratio as the energy is transferred into the liquid more uniformly. The energy may also be transferred into the liquid through a non-conductive surface to eliminate the risk of forming steam and/or bubbles due to “hot spots” generally accompanied with rapid heating using conductive methods. The end result is similar to microwave heating of a liquid except higher electrical to thermal efficiencies can be realized. Using a resonant inverter at megahertz frequencies also may provide very fast response time and fine control over the heating system. Strategies for passive/natural power factor correction may be incorporated that limit or eliminate the need for an active power factor correction stage common in more conventional switching regulators. In various embodiments, the control circuitry of the control unit may provide output signals to control a device, such as fluid pump, wherein the flow rate of the liquid is adjusted so as to maintain the monitored temperature at, or within a band around, a constant value.
In various embodiments, the passageway for the flow of fluid to be heated includes a flexible passageway. In various embodiments, the fluid to be heated is an ionic liquid. In various embodiments, the fluid to be heated is saline, and is physiological saline. In various embodiments, wherein the temperature of the fluid being heated is to be maintained within a temperature range of between 49° C. and 51° C., inclusive. In various embodiments, the fluid exiting the conduit conveying the heated fluid from the non-contact radio-frequency heating element is configured for conveying heat to a liquid and delivering said liquid at a temperature elevated above that of the human body into an external body orifice, such as but not limited to a urinary meatus of a patient. Various embodiments further include a catheter extending through the urethra of a patient for receipt within the bladder and configured to convey a fluid heated by a non-contact radio-frequency heating unit to the bladder of a patient.
In various embodiments, the control unit includes a resonant inverter, such as but not limited to a Class E resonant inverter. In various embodiments, the Class E resonant inverter further comprises a wide-bandgap transistor, and/or wherein the signal driving the gate of the transistor comprising the Class E resonant inverter is supplied by the microcontroller. In various embodiments, the supply to the Class E resonant inverter is the unfiltered rectified line voltage.
In various embodiments, the input voltage of the resonant electrical waveform generator is configured to vary in time at the fundamental of the line frequency (50 Hz or 60 Hz), and as a result the current drawn by the electrical waveform generator scales with voltage. If the voltage at the input of the electrical waveform generator is allowed to drop nearly to zero in sync with the rectified line, the electrical waveform generator itself may present approximately a resistive load to the line, and therefore nearly unity power factor can be achieved without any active or passive filtering elements.
In various embodiments, one or more of the temperature sensors configured to provide an output signal to the control unit may be read by the control circuitry during an OFF cycle of the modulation of the electrical output waveform(s) being provided to the electrode output terminal of the control unit. Temperature (and other) measurements may be susceptible to noise from switching power converters. Incorporation of temperature sensor(s) that can be read during the off-cycle modulation such that no switching noise is present, greatly improving the accuracy of the temperature reading. In various embodiments, one or more of the temperature sensors configured to provide an output signal to the control unit may be read during a minimum voltage level of the rectified line voltage. The gating of the resonant electrical waveform generator is disabled at the minimum rectified line voltage at the point of approximately zero power such that the temperature reading and off period due not adversely affect the power factor characteristics of the system.
In various embodiments, the ON and OFF switching cycles and the modulation periods may be synchronized with the line voltage or other electrical power input provided to the control unit. In various embodiments, the principal AC frequency; or the duty cycle of the transistor gate drive signal; are adjusted so as to optimize the heating efficiency; delivered power; or the power factor of the apparatus. As input voltage to the resonant electrical waveform generator varies with the rectified line voltage or otherwise, the optimal switching frequency and/or duty cycle may be affected, leading to reduced efficiency, and/or power factor. Varying frequency and/or duty cycle can lead to optimal efficiency and power factor for a given instantaneous input voltage or load impedance. Frequency and/or duty cycle may also be used to control power delivered to the load by deliberately tuning/detuning the impedance seen by the electrical waveform generator.
In various embodiments, the impedance characteristics of the liquid being heated is sensed by the control unit, and a resultant temperature is determined based on said impedance values. The impedance of saline changes very predictably with temperature. By monitoring the electrical performance of the electrical waveform generator during operation, the impedance can be determined and thus real-time temperature of the liquid can be predicted.
Various examples including and transporting the heated liquid into a human body where in the vicinity of the entry orifice of said liquid into the body, the temperature of the liquid is above that of the body.
In various embodiments the control unit in conjunction with a non-contact radio-frequency heating element may utilize high voltage DC pulses to transfer electrical energy into a liquid. The process of pulse electric field sterilization (PEF) is a method of applying high voltage DC pulses (could be bipolar DC voltages) to a liquid in order to destroy the cell walls of any bacteria that may be present within the liquid. In addition to sterilizing the liquid, the temperature of the liquid also increases moderately. PEF can be used to both sterilize and heat the liquid in real-time. The DC pulses can be on the order of 1 microsecond or greater in length. Generally, electric field strengths of 800 V/mm or higher are desired to achieve significant bacteria reduction in a liquid. The electrode strategy is similar to the AC method but in various embodiments may have exposed electrodes in contact with the liquid, such as metal electrodes.
Embodiments of method 700 may include processing incoming electrical power to produce processed electrical power, (block 702). Processing of electrical power may include rectification, filtering, and voltage, current, and/or phase regulation of incoming electrical power. In various embodiments, processor(s) of the control circuitry may provide control signals, for example to an input power processing circuitry, to modify or control one or more parameters, such as a voltage or a power level provided an output of the electrical power processed and provided as an output from the input power processing circuitry.
Embodiments of method 700 may include generating and modulating an RF waveform to produce an intermediate electrical waveform, (block 704). Generation of an RF waveform may be performed by an RF source, such as RF source 204A (
Embodiments of method 700 may include controlling a power-delivery circuitry using the intermediate electrical waveform to control coupling of the processed electrical power to one or more sets of electrodes of a RF heating element (block 706). In various embodiments, the control provided by power-delivery circuitry may include switching ON and switching OFF the electrical coupling between the processed electrical power being provided to the power-delivery circuitry and the one or more sets of electrodes in order to provide a modulated or a pulsed electrical output waveform to the one or more sets of electrode included in the RF heating element, and thereby control the heating of a fluid flowing through or contained within the heating element. Embodiments of method 700 may include coupling the electrical output waveform from the one or more electrode output terminals of a control unit to one or more sets of electrodes positioned in a non-contact radio-frequency heating elements through one or more electrical conductors, such as but not limited to one or more shielded co-axial cables. Providing the electrical output waveform from the one or more electrode output terminals to one or more sets of electrodes positioned in a non-contact radio-frequency heating element may result in a heating of a fluid passing between or contained within an area between the one or more sets of electrodes.
Embodiments of method 700 may include sensing parameters associated with a fluid flowing through and/or contained within the RF heating element (block 708). Sensed parameter may include but are not limited to sensing a temperature of the fluid, sensing a flow rate or a flow volume associated with the fluid, and/or sensing of a impedance value of the electrical circuit including the electrodes and the fluid present within the area between the electrodes.
Embodiments of method 700 may include determining, for example using control circuitry, adjustments to the electrical power that is/are being applied to the one or more sets of electrodes of the non-contact radio-frequency heating element based at least in part on the sensed parameters (block 710). In various embodiments, a determination of any adjustments to the electrical output waveform(s) is based on one or more sensed temperatures associated with the fluid being heated by the non-contact radio-frequency heating element. In various embodiments, a determination of any adjustments to the electrical output waveform(s) is based on one or more sensed flow rates or a sensed flow volume associated with the fluid being heated by the non-contact radio-frequency heating element. In various embodiments, a determination of any adjustments to the electrical output waveform(s) is based on one or more sensed impedance values measured for the electrical circuitry that includes the electrodes of the non-contact radio-frequency heating element and the fluid being heated by the non-contact radio-frequency heating element.
Based on a determination of any adjustment that may need to be made to the electrical output waveform(s), method 700 returns to block 704, as indicated by return line 714, where further control of the electrical waveform generator and/or the power-delivery circuitry is performed based on any of the adjustments determined to be made at block 710. Heating of the fluid may continue in a loop including blocks 702 through 710 until an operator shuts the control unit that is performing method 700 off, or an alarm condition is detected (block 720).
When an alarm condition is detected, embodiments of method 700 may include shutting down the electrical waveform generator and/or the power-delivery circuitry of the control unit. Alarm conditions can include but are not limited to an over temperature detected for the fluid being heated by the non-contact radio-frequency heating element, an unacceptable condition related to the flow rate or flow volume associated with the fluid being heated by the non-contact radio-frequency heating unit, and/or an electrical or temperature condition associated with the control unit and/or the non-contact radio-frequency heating unit, such as a short circuit, loss of input electrical power to the control unit, and any unacceptable and detected over temperature, overcurrent, or overvoltage condition that might exist within the control unit. In various embodiments, the control unit is configured to output a warning signal, for example through a user interface, to one or more devices located external to the control unit, the warning signal(s) including information related to the detection of an alarm condition, and/or information related to the nature and the extent of the condition that generated the alarm condition.
As will be appreciated, aspects of the disclosure may be embodied as a system, method or program code/instructions stored in one or more machine-readable media. Accordingly, aspects may take the form of hardware, software (including firmware, resident software, micro-code, etc.), or a combination of software and hardware aspects that may all generally be referred to herein as a “circuit,” “circuitry,” “module,” or “system.” The functionality presented as individual modules/units in the example illustrations can be organized differently in accordance with any one of platform (operating system and/or hardware), application ecosystem, interfaces, programmer preferences, programming language, administrator preferences, etc.
Any combination of one or more machine readable medium(s) may be utilized. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable storage medium may be, for example, but not limited to, a system, apparatus, or device, that employs any one of or combination of electronic, magnetic, optical, electromagnetic, infrared, or semiconductor technology to store program code. More specific examples (a non-exhaustive list) of the machine readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a machine readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. A machine readable storage medium is not a machine readable signal medium.
While the aspects of the disclosure are described with reference to various implementations and exploitations, it will be understood that these aspects are illustrative and that the scope of the claims is not limited to them. In general, techniques for non-contact radio-frequency heating control units and non-contact radio-frequency heating elements as described herein may be implemented with facilities consistent with any hardware system or hardware systems. Many variations, modifications, additions, and improvements are possible.
Plural instances may be provided for components, operations or structures described herein as a single instance. Finally, boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of the disclosure. In general, structures and functionality presented as separate components in the example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure.
Use of the phrase “at least one of” preceding a list with the conjunction “and” should not be treated as an exclusive list and should not be construed as a list of categories with one item from each category, unless specifically stated otherwise. A clause that recites “at least one of A, B, and C” can be infringed with only one of the listed items, multiple of the listed items, and one or more of the items in the list and another item not listed.
Example embodiments include the following.
Embodiment 1. An apparatus comprising: a control unit for heating a fluid within a non-contact radiofrequency heating element, the control unit comprising: a radio-frequency (RF) source configured to generate an electrical waveform; a modulator coupled to the RF source and configured to receive the electrical waveform from the RF source and to generate an intermediate electrical waveform having a waveform based at least in part on the electrical waveform; and a power-delivery circuitry coupled to the modulator and configured to receive an electrical power input and to receive the intermediate electrical waveform, and a to generate an electrical output waveform using the electrical power input, the electrical output waveform corresponding to the intermediate electrical waveform; wherein the power-delivery circuitry is configured to deliver the electrical output waveform to a set of electrodes included as part of the non-contact radiofrequency heating element, the set of electrodes positioned proximate to a fluid flow passageway of the radiofrequency heating element while not in fluid communication with the fluid flow passageway, and wherein the electrical output waveform is configured to produce volumetric radiofrequency heating in a fluid contained within the fluid flow passageway when the electrical output waveform is being applied to a set of electrodes and while the set of electrodes is not in physical contact with the fluid.
Embodiment 2. The apparatus of embodiment 1, wherein the control unit further comprises a control circuitry including at least one processor, wherein the at least one processor is communicatively coupled to the modulator, and wherein the at least one processor is configured to provide one or more control signals to the modulator to control at least one parameter of the intermediate electrical waveform generated by the modulator.
Embodiment 3. The apparatus of embodiment 2, wherein controlling at least one parameter of the intermediate electrical waveform includes controlling a duty cycle of the intermediate electrical waveform.
Embodiment 4. The apparatus of embodiment 2, wherein the control unit further comprises one or more sensor inputs, the one or more sensor inputs coupled to the control circuitry and configured to receive one or more sensor signals generated by one or more sensors, and wherein the at least one processor is configured to process the one or more sensor signals, and to generate the one or more control signals provided to the modulator based at least in part on the one or more sensor signals.
Embodiment 5. The apparatus of embodiment 4, wherein at least one of the one or more sensor signals is generated by a temperature sensor, and is configured to provide a signal corresponding to a sensed temperature of the fluid flowing through or exiting the non-contact radiofrequency heating element.
Embodiment 6. The apparatus of embodiment 4, wherein at least one of the one or more sensor signals is generated by a flow sensor, and is configured to provide a signal corresponding to a sensed flow rate of the fluid flowing through or exiting the non-contact radiofrequency heating element.
Embodiment 7. The apparatus of embodiment 4, wherein at least one of the one or more sensor signals is generated by a ambient temperature sensor, and is configured to provide a signal corresponding to a sensed temperature of an ambient area where a fluid source configured to provide the fluid flow to the non-contact radiofrequency heating element is located.
Embodiment 8. The apparatus of any of embodiments 1 to 7, wherein the electrical output waveform generated by the electrical waveform generator has a frequency in a range of 10 kilohertz to 30 megahertz, inclusive.
Embodiment 9. The apparatus of any of the embodiments 1 to 8, wherein at least some portion of the electrical output waveform configured to be delivered to the set of electrodes comprises a sine wave.
Embodiment 10. The apparatus of any of embodiments 1 to 9, wherein the electrical output waveform is configured to produce volumetric radiofrequency heating in a fluid comprising saline.
Embodiment 11. The apparatus of any of embodiments 1 to 10, wherein the power-delivery circuitry comprises one or more electrical switching devices configured to controllably connect and disconnect the electrical output waveform to and from, respectively, the set of electrodes.
Embodiment 12. The apparatus of any of embodiments 1 to 11, wherein the control unit comprises a plurality of electrode output terminals, each of the plurality of electrode output terminals configured to be electrically coupled to a separate one of the set of electrodes included as part of the non-contact radiofrequency heating element, and wherein the power-delivery circuitry is configured to connect and disconnect the electrical output waveform to and from, respectively, each of the plurality of electrode output terminals individually.
Embodiment 13. A system comprising: a non-contact radiofrequency heating element comprising a set of electrodes arranged proximate to a fluid passageway extending through the non-contact radiofrequency heating element, the set of electrodes physically isolated from the fluid passageway by a barrier and configured to produce non-contact radio-frequency heating in a fluid flowing through the fluid passageway when an electrical output waveform is applied to the set of electrodes; and a control unit coupled to the non-contact radiofrequency heating element and configured to provide the electrical output waveform for heating the fluid flowing within the non-contact radiofrequency heating element, the control unit comprising: a radio-frequency (RF) source configured to generate an electrical waveform; a modulator coupled to the RF source and configured to receive the electrical waveform from the RF source and to generate an intermediate electrical waveform having a waveform based at least in part on the electrical waveform; and a power-delivery circuitry coupled to the modulator and configured to receive an electrical power input and to receive the intermediate electrical waveform, and a to generate an electrical output waveform from using the electrical power input, the electrical output waveform corresponding to the waveform of the intermediate electrical waveform; wherein the power-delivery circuitry is configured to deliver the electrical output waveform to the set of electrodes included as part of the non-contact radiofrequency heating element, and wherein the electrical output waveform is configured to produce volumetric radiofrequency heating in a fluid contained within the fluid flow passageway when the electrical output waveform is being applied to a set of electrodes and while the set of electrodes is not in physical contact with the fluid.
Embodiment 14. The system of embodiment 13, wherein the non-contact radiofrequency heating control unit further comprises one or more sensor inputs, the one or more sensor inputs coupled to the control unit and configured to receive one or more sensor signals generated by one or more sensors, and to couple the one or more sensor signals to at least one processor, wherein the processor is configured to process the one or more sensor signals, and to generate one or more control signals provided to the modulator to control the generation of the intermediate electrical waveform based at least in part on the sensor signals.
Embodiment 15. The system of embodiment 14, wherein at least one of the one or more sensor signals is generated by a temperature sensor, and is configured to provide a signal corresponding to a sensed temperature of the fluid flowing through or exiting the non-contact radiofrequency heating element.
Embodiment 16. The system of any of embodiments 13 to 15, wherein at least some portion of the intermediate electrical waveform generated by the modulator comprises a frequency in a range of 10 kilohertz to 30 megahertz, inclusive.
Embodiment 17. The system of any of embodiments 13 to 16, wherein the intermediate electrical waveform generated by the modulator comprises a sine wave.
Embodiment 18. The system of any of embodiments 13 to 17, wherein the control unit is configured to control the non-contact radio-frequency heating of a flow of a saline fluid flowing through the non-contact radiofrequency heating element.
Embodiment 19. The system of any of embodiments 13 to 18, wherein the power-delivery circuitry comprises one or more electrical switching devices configured to controllably connect and disconnect the electrical output waveform to and from, respectively, the set of electrodes.
Embodiment 20. The system of any of embodiments 13 to 19, wherein the control unit comprises a plurality of electrode output terminals, each of the plurality of electrode output terminals configured to be electrically coupled to a separate one of the set of electrodes included as part of the non-contact radiofrequency heating element, and wherein the power-delivery circuitry is configured to connect and disconnect the electrical output waveform to and from, respectively, each of the plurality of electrode output terminals individually.
Embodiment 21. A method comprising: generating a radiofrequency(RF) waveform; modulating the RF waveform to produce and intermediate electrical waveform; and controlling a power-delivery circuitry using the intermediate electrical waveform to controllably couple an electrical output waveform to a set of electrodes included as part of a radiofrequency heating element, the set of electrodes positioned proximate to a fluid flow passageway of the radiofrequency heating element while not in fluid communication with the fluid flow passageway; wherein the electrical output waveform is configured to produce volumetric radiofrequency heating in a fluid contained within the fluid flow passageway when the electrical output waveform is being applied to a set of electrodes and while the set of electrodes is not in physical contact with the fluid.
Embodiment 22. The method of embodiment 21, further comprising: receiving a sensor output signal corresponding to a sensed temperature of the fluid; and adjusting at least one parameter of the electrical output waveform being applied to the set of electrodes based at least in part on the sensed temperature.
Embodiment 23. The method of embodiment 22, wherein adjusting the at least one parameter of the electrical output waveform comprises adjusting a duty cycle of electrical output waveform.
Embodiment 24. The method of embodiment 22, wherein adjusting the at least one parameter of the electrical output waveform comprises adjusting a voltage level of the electrical output waveform.
Embodiment 25. The method of embodiment 22, wherein adjusting the at least one parameter of the electrical output waveform comprises adjusting a frequency of the electrical output waveform.
Embodiment 26. The method of any of embodiments 21 to 25, wherein at least some portion of the electrical output waveform comprises a sine wave having a frequency in a range of 10 kilohertz to 30 megahertz, inclusive.
Embodiment 27. The method of any of embodiments 21 to 26, wherein the set of electrodes comprises four electrodes and at least one return electrode.
Embodiment 28. The method of any of embodiments 21 to 27, further comprising: monitoring a sensor signal corresponding to a temperature of the fluid being heated, determining that the temperature of the fluid has exceeded a temperature threshold value based on the sensor signal; and controlling a shutdown of the modulator or a power-delivery circuitry so that the electrical output waveform is no longer applied to the set of electrodes.
Embodiment 29. A non-transitory, computer-readable medium having instructions stored thereon that are executable by a computing device to perform operations comprising: generating a radiofrequency(RF) waveform; modulating the RF waveform to produce and intermediate electrical waveform; and controlling a power-delivery circuitry using the intermediate electrical waveform to controllably couple an electrical output waveform to a set of electrodes included as part of a radiofrequency heating element, the set of electrodes positioned proximate to a fluid flow passageway of the radiofrequency heating element while not in fluid communication with the fluid flow passageway; wherein the electrical output waveform is configured to produce volumetric radiofrequency heating in a fluid contained within the fluid flow passageway when the electrical output waveform is being applied to a set of electrodes and while the set of electrodes is not in physical contact with the fluid.
Embodiment 30. The non-transitory, computer-readable medium of embodiment 29, further comprising: monitoring a sensor signal corresponding to a temperature of the fluid being heated, determining that the temperature of the fluid has exceeded a temperature threshold value based on the sensor signal; and shutting down the power-delivery circuitry so that the electrical output waveform is no longer applied to the set of electrodes.
Filing Document | Filing Date | Country | Kind |
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PCT/US2020/057339 | 10/26/2020 | WO |
Number | Date | Country | |
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62933173 | Nov 2019 | US |