US-20260124069-A1 - HEATING DEVICE FOR PERFUSION FLUID, CHANNEL AND HEATING ASSEMBLY

Abstract

The invention relates to a heating device ( 100 ) for heating a fluid used in a medical procedure, comprising: a holder ( 110 ) arranged for receiving a channel ( 10 ) comprising a channel wall ( 11 ) arranged for conducting the fluid; and an electrical circuit ( 120 ) comprising: a first conductive surface ( 135 ), arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a first capacitor ( 130 ) contributing to the capacitance of the electrical circuit, and for generating a first electrical field in the channel wall for introducing a first capacitively coupled current in the fluid; a second conductive surface ( 155 ), arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a second capacitor ( 150 ) contributing to the capacitance of the electrical circuit, and for generating a second electrical field in the channel wall for introducing a second capacitively coupled current in the fluid; and an inductor ( 140 ) contributing to the inductance of the electrical circuit, and arranged to the holder for generating a magnetic field for introducing an inductively coupled current in the fluid; wherein the electrical circuit further comprises a connector ( 125, 125 ′) electrically coupled to the first conductive surface, the second conductive surface and the inductor, and couplable to a power source providing a quasi-static AC power to the electrical circuit at an operating frequency.

Inventors

• Klaus Werner
• Stephan Holtrup
• Anna Helena TER STEGE-HAKE

Assignees

• THERMASOLUTIONS LLC
• THERMASOLUTIONS EUROPE B.V.

Dates

Publication Date

20260507

Application Date

20251222

Priority Date

20220901

Claims (20)

1. 1 .- 36 . (canceled)
2. 37 . A heating device for heating a fluid used in a medical procedure, comprising: a holder arranged for receiving a channel comprising a channel wall arranged for conducting the fluid; and an electrical circuit comprising: a first conductive surface, arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a first capacitor contributing to the capacitance of the electrical circuit, and for generating a first electrical field in the channel wall for introducing a first capacitively coupled current in the fluid; a second conductive surface, arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a second capacitor contributing to the capacitance of the electrical circuit, and for generating a second electrical field in the channel wall for introducing a second capacitively coupled current in the fluid; and an inductor contributing to the inductance of the electrical circuit, and arranged to the holder for generating a magnetic field for introducing an inductively coupled current in the fluid; wherein the electrical circuit further comprises a connector electrically coupled to the first conductive surface, the second conductive surface and the inductor, and couplable to a power source providing a quasi-static AC power to the electrical circuit at an operating frequency; and wherein the fluid is selected from a perfusion fluid, a transfusion fluid, and an infusion fluid.
3. 38 . The heating device of claim 37 , wherein one of the channel has a channel diameter and a longitudinal axis; the distance between the first conductive surface and the second conductive surface along the longitudinal axis is at least 1.0 times; the distance between the first conductive surface and the second conductive surface along the longitudinal axis is at most 15 times the channel diameter; and the first conductive surface and the second conductive surface are arranged such that respectively the first capacitively coupled current in the fluid is substantially a first axial current and the second capacitively coupled current in the fluid is substantially a second axial current.
4. 39 . The heating device of claim 37 , wherein the first conductive surface has a first truncated conical inner shape; the second conductive surface has a second truncated conical inner shape; and the channel wall has at least a partly truncated conical shape for cooperating with the first conductive surface and the second conductive surface.
5. 40 . The heating device of claim 39 , wherein the first truncated conical shape has a minimum diameter; the second truncated conical shape has a maximum diameter; and the minimum diameter is larger than the maximum diameter; or the first truncated conical shape and the second truncated conical shape are aligned to form one virtual conical shape; or the inductor is arranged for surrounding the channel.
6. 41 . The heating device of claim 37 , wherein the channel comprises an input opening and an output opening; and the input opening and the output opening are arranged on the same side of the magnetic field, the inductor, the first electric field, the second electric field, the first conductive surface and/or the second conductive surface; or the second capacitively coupled current matches the first capacitively coupled current for introducing a capacitively coupled current in the fluid between the first conductive surface and the second conductive surface; or the first conductive surface and the second conductive surface are arranged on either side of the inductor, such that the first capacitively coupled current and the second capacitively coupled current flow through the magnetic field.
7. 42 . The heating device of claim 37 , wherein the inductor is split in a first half and a second half; the first half of the inductor and the second half of the inductor are electrically coupled to the connector; an other side of the first half of the inductor is electrically coupled to the first conductive surface; and an other side of the second half of the inductor is electrically coupled to the second conductive surface; or in use the fluid has a resistivity per volume; the first conductive surface and the second conductive surface are spaced apart a coupling distance; and the coupling distance is selected such that the fluid resistivity between the first conductive surface and the second conductive surface substantially matches the output resistivity of the power source.
8. 43 . The heating device of claim 37 , wherein the fluid is a perfusion fluid.
9. 44 . The heating device of claim 37 , wherein the fluid is a transfusion fluid.
10. 45 . The heating device of claim 37 , wherein the fluid is an infusion fluid.
11. 46 . The heating device of claim 37 , wherein in use the channel wall at the first conductive surface has a first relative permittivity; in use the first capacitor has a first capacitance depending on the first relative permittivity and a thickness of the channel wall local to the first conductive surface; in use the channel wall at the second conductive surface has a second relative permittivity; in use the second capacitor has a second capacitance depending on the second relative permittivity and a thickness of the channel wall local to the second conductive surface; in use the fluid has a magnetic permeability; the inductance is based on the magnetic permeability of the fluid; the electrical circuit has a resistance based on the resistivity of the first capacitively coupled current, the inductively coupled current, and the second capacitively coupled current; the electrical circuit has a reactance based on the capacitance and the inductance; and at the operating frequency, the ratio of the resistance and reactance is more than 2:1.
12. 47 . The heating device of claim 37 , wherein the operating frequency is below 450 MHz; the operating frequency is within the range of 433.05 MHz to 434.79 MHz; the operating frequency is within the range of 40.66 MHz to 40.7 MHz; the operating frequency is within the range of 26.957 MHz to 27.283 MHz; the operating frequency is within the range of 13.553 MHz to 13.567 MHz; or the operating frequency is within the range of 6.765 to 6.795 MHz.
13. 48 . The heating device of claim 37 , wherein in use the electrical circuit has a Q-factor based on the resistance, the capacitance, and the inductance; the Q-factor is selected to accommodate for changes of the relative permittivity of the fluid and/or the magnetic permeability of the fluid over the temperature range of the fluid, and/or for changes of the relative permittivity of the fluid and/or the magnetic permeability of the fluid over different production batches; the Q-factor is selected to accommodate in use for an air gap between the channel wall and the first conductive surface, the channel wall and the second conductive surface, of up to 100 μm; and the heating device comprises a reactance sensor for sensing a reactance of the electric circuit relative to a predefined reactance range for detecting the presence of a channel in the holder, the correct placing of the channel in the holder, the filling degree of the channel with fluid, and/or if the correct fluid is in the channel.
14. 49 . The heating device of claim 37 , wherein the heating device is arranged for heating the fluid up under atmospheric pressure to a maximum temperature of 55 degrees Celsius; the holder is arranged for replacing the channel; the channel has an outer channel shape, and the holder has a tapered shape for receiving a tapered outer channel shape; or in use the fluid has a magnetic permeability, in use the channel has a magnetic permeability, and the electric circuit is arranged for a fluid and a channel wherein the channel magnetic permeability is neglectable compared to the fluid magnetic permeability, such as in a ratio of 1:5; or in use the fluid has a relative permittivity, in use the channel has a relative permittivity, and the electric circuit is arranged for a fluid and a channel wherein the fluid relative permittivity is neglectable compared to the channel relative permittivity, such as in a ratio of 1:25.
15. 50 . A heating assembly comprising: the heating device of claim 37 ; and a channel for use in the heating device.
16. 51 . A flow sensor for measuring the flow of a fluid in a conduit, comprising: the heating device of claim 37 ; a first temperature sensor arranged upstream of the heating device for measuring the temperature of the fluid going into the heating device; a second temperature sensor arranged downstream of the heating device for measuring the temperature of the fluid coming from the heating device; and an electrical power sensor arranged for measuring the electrical power inputted into the fluid by the heating device; and a controller arranged for: receiving a first temperature from the first temperature sensor; receiving a second temperature from the second temperature sensor; receiving an electrical power value representing the electrical power inputted into the fluid; retrieving the thermal capacity of the fluid; retrieving the volumetric mass density of the fluid; and calculating the flow of the fluid based on the first temperature, the second temperature, the electrical power value, the thermal capacity, and the volumetric mass density.
17. 52 . The flow sensor of claim 51 , wherein the step of calculating comprises the steps of: subtracting the first temperature from the second temperature for providing a temperature change; determining a received energy value based on the heat capacity and the temperature change; dividing the electrical power value by the received energy for providing the mass per time unit of the flow; and dividing the mass of the flow by the volumetric mass density for providing the volume per time unit of the flow.
18. 53 . The flow sensor of claim 52 , further comprising a first pressure sensor arranged for measuring the pressure of the fluid at the first temperature sensor; and a second pressure sensor arranged for measuring the pressure of the fluid at the second temperature sensor; wherein the step of determining a received energy value is based on the pressure measurement of the first pressure sensor and the pressure measurement of the second sensor, more specific on the pressure difference of the fluid at the first temperature sensor and at the second temperature sensor.
19. 54 . A temperature sensor for sensing the temperature of a fluid, comprising: the heating device according to claim 37 , wherein the fluid is conducted in the channel; a power source providing a quasi-static AC power to the electrical circuit of the heating device, comprising: a supply circuit for generating the operating frequency at a power output; and an impedance sensor for detecting an impedance of the electrical circuit; and a controller arranged for: retrieving a function relating temperature and resonance frequency of the fluid; determining a resonance frequency of the fluid in the channel based on changing the operating frequency; and determining the fluid temperature of the fluid in the channel based on the resonance frequency and the function relating temperature and resonance frequency.
20. 55 . The temperature sensor of claim 54 , wherein the step of determining the resonance frequency comprises: changing the operating frequency over a frequency range; receiving impedance measurements, measured while changing the operating frequency, from the impedance sensor for detecting the impedance; and determining the resonance frequency based on an operating frequency with a lowest impedance.

Description

FIELD OF THE INVENTION The invention relates to a heating device for heating a fluid used in a medical procedure. The invention further relates to a channel for use in a heating device. The invention further relates to a heating assembly comprising the heating device and the channel. BACKGROUND OF THE INVENTION Perfusion is a medical procedure where a fluid is passed through the circulatory system or lymphatic system to an organ or a tissue. Hyperthermic perfusion is a medical procedure, in which a warmed solution containing anticancer drugs, is used to bathe, or is passed through the blood vessels of, the tissue or organ containing the tumour. A known solution providing a sterile heating of the perfusion fluid is to heat a primary fluid. The primary fluid is then passed through a heat exchanger together with the perfusion fluid to transfer the heat to the perfusion fluid. A disadvantage is that the temperature control of the perfusion fluid is coarse as well as slowly ramping up. Another solution is to place a heating element inside the channel. A disadvantage of this solution is that local to the heating element the fluid can get very hot, such that local temperatures exceed some predefined temperature causing irreversible changes in the fluid, which typically contains medicines or proteins. SUMMARY OF THE INVENTION An object of the invention is to overcome one or more of the disadvantages mentioned above. According to a first aspect of the invention, a heating device for heating a fluid used in a medical procedure, comprising: a holder arranged for receiving a channel comprising a channel wall arranged for conducting the fluid; and an electrical circuit comprising: a first conductive surface (135), arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a first capacitor contributing to the capacitance of the electrical circuit, and for generating a first electrical field in the channel wall for introducing a first capacitively coupled current in the fluid; a second conductive surface (155), arranged to the holder for in use annularly surrounding the channel and together with the channel wall and the fluid forming a second capacitor (150) contributing to the capacitance of the electrical circuit, and for generating a second electrical field in the channel wall for introducing a second capacitively coupled current in the fluid; and an inductor contributing to the inductance of the electrical circuit, and arranged to the holder for generating a magnetic field for introducing an inductively coupled current in the fluid; wherein the electrical circuit further comprises a connector electrically coupled to the first conductive surface, the second conductive surface and the inductor, and couplable to a power source providing a quasi-static AC power to the electrical circuit at an operating frequency. The holder is shaped for receiving the channel. The channel may have a particular shape for accommodating use in a medical room, such as an operating room. The channel may be couplable to tubing, conduits and/or ducts for guiding the fluid from and to the patient for forming a fluid circuit. The channel comprises a channel wall impermeable for the fluid and for guiding, conducting and/or carrying the fluid in a predefined direction. The holder may have a beaker shape. The heating device may comprise a housing forming the holder. The fluid may be a perfusion fluid, an infusion fluid, a transfusion fluid, blood, or any other fluid that might be used in a medical procedure. The electric circuit comprises a first conductive surface for forming in use a first capacitor, and an inductor. The electrical circuit further comprises a connector. The connector is electrically coupled to the first conductive surface and the inductor, such that when the connector is coupled to a power source providing power, the first conductive surface and the inductor are provided with this power from the power source. The power from the power source is quasi-static AC power. AC is short for alternating current. Quasi-static limits the frequencies provided by the power source to the electrical circuit. Quasi-static may be Galilean electromagnetism. Quasi-static may be considered as local equilibrium thermodynamics. Quasi-static are typically frequencies of which the wavelength of the AC power is larger than the size of the heating device, such as twice, preferably five times, more preferably ten times, most preferably twenty times. Quasi-static AC power typically means that the wave properties or wave propagation effects inside the heating device may be neglected or are neglectable when modelling the circuit, when modelling the working of the heating device, and/or when predicting efficiency and/or effects of the heating device, more specific the electrical circuit. The first capacitor comprises a first conductive surface. The first conductive surface is arranged to the holde