BREATHING SYSTEM DEVICE FOR CO2 REMOVAL BASED ON AN ELECTRO-CHARGING AND DISCHARGING METHOD

Abstract

The invention relates to a reusable device for CO2 removal, suitable for use in a breathing system, as part of an anaesthesia arrangement, and based on an electro-charging and discharging method. The invention is related to holders, containers and so-called canisters including any subparts of such devices and methods of operating used in an anaesthesia arrangement, wherein the CO2 removal takes place.

Claims

1-14. (canceled)

15. A device for CO2 removal from an expiration or breathing gas stream, suitable for use in a breathing system, part of an anaesthesia arrangement, the device comprising: a holder adapted for fitting in the breathing system; and a container for CO2 removal from a gas stream, the container being adapted for fitting in the holder, wherein: the CO2 removal by the container is based on an electro-charging and discharging method, the container comprises a plurality of plates arranged in that the expiration or breathing gas stream passes between the plates; each of the plates comprises at least two electrodes arranged for charging and/or discharging the plates; and the at least two electrodes comprise an active electrode and a counter electrode separated from the active electrode by a separator; and the device further comprises means for providing electricity to the active electrode and/or the counter electrode.

16. The device of claim 15, wherein the plurality of plates are adapted for absorbing CO2 when the electrodes are being charged and for releasing CO2 when the electrodes are being discharged.

17. The device of claim 15, further comprising electronic means to control charging or discharging of the electrodes.

18. The device of claim 15, adapted for having a pressure less than 2 mbar at a nominal flow rate from 20 L/min to 65 L/min, and comprising at least two plates, wherein a distance d between the plates or the electrodes thereof is selected therefor.

19. The device of claim 15, wherein a surface of the electrodes is selected to react with CO2 in the gas stream.

20. The device of claim 19, wherein the surface of the electrodes is covered with a polymer, the polymer comprising a material for attracting CO2.

21. The device of claim 20, wherein the material for attracting CO2 is (anthra)quinone.

22. The device of claim 21, adapted to be operable for concentrations of CO2 as low as about 400 ppm by selecting an amount of (anthra)quinone and a total surface applicable in the container.

23. The device of claim 19, wherein the surface of the electrodes is covered with a polymer, the polymer comprising a material for enhancing conductivity of the electrodes.

24. The device of claim 23, wherein the material for enhancing conductivity of the electrodes comprises carbon nanotubes.

25. The device of claim 19, wherein the surface of the electrodes is covered with a polymer, the polymer comprising (anthra)quinone for attracting CO2 and carbon nanotubes for enhancing conductivity of the electrodes.

26. The device of claim 15, adapted for being operable for at least one day, by adjusting a number of the plates in the container for CO2 removal.

27. The device of claim 15, adapted to be operable for at least 2000 charging-discharging cycles with less than 30% efficiency loss of charging-discharging operation.

28. A breathing system comprising the device for CO2 removal from a gas stream according to claim 15.

29. An anaesthesia arrangement comprising the breathing system according to claim 28.

30. An electro-charging and discharging method for operating the device according to claim 15 for CO2 removal from an exhaustion or breathing gas stream in a breathing system as part of an anaesthesia arrangement, the method comprising: when the device is installed in a gas flow circulation of the breathing system from which CO2 is to be removed, providing electricity of a first polarity to the container to charge the electrodes; and when the device is removed from the gas flow circulation, providing electricity of a second polarity opposite the first polarity to the container to discharge the electrodes.

31. A discharging equipment, adapted to receive the device according to claim 15 and to provide electricity of a suitable polarity for discharging the device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 illustrates schematically an embodiment of a device comprising an electrochemical plate and corresponding electrodes for CO2 removal from a gas stream, suitable for use in a breathing system, part of an anaesthesia arrangement, in accordance with the invention.

[0020] FIG. 2 shows a further embodiment of a device comprising two electrochemical plates with respective electrodes for CO2 removal from a gas stream, suitable for use in a breathing system, part of an anaesthesia arrangement, in accordance with the invention.

[0021] FIG. 3 illustrates a more detailed version of the embodiment of FIG. 1 including means to provide electricity to the CO2 removal device, in accordance with the invention.

[0022] FIG. 4 illustrates an exemplary embodiment of (a) charging, and (b) discharging process of a CO2 removal device with a plate defined by electrodes and separators there in between, and wherein means for providing electricity to the electrodes are foreseen, in accordance with the invention.

[0023] FIG. 5 illustrates an embodiment of the use of the CO2 removal device in a breathing system context, in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] With the present invention, a traditional soda lime canister is replaced by a canister, holder or device containing a stack of electrochemical plates absorbing carbon dioxide from the circuit breathing gasses (or other gas stream) passing over its electrodes or e.g. a stack of electrodes, as the electrodes of the plates are charged up, and then releasing the CO2 gas as the electrodes of the plates are discharged. Hence, a new way of removing CO2 in the breathing system (wherein a stream of rebreathing gasses of the patient and/or fresh gas mixture is circulated) of an anaesthesia arrangement or workstation, is provided by means of an electro-charging and discharging system. According to an embodiment, CO2 is removed from a gas mixture of air, oxygen, nitrous oxide and/or anaesthetic agent (isoflurane, enflurane, desflurane, halothane and sevoflurane). This mixture may be either as combination of these different gasses, as well as in combination with individual gasses.

[0025] While charging, an electrochemical reaction takes place at the surface of the electrodes (or each of a stack of electrodes) and will attract the CO2 in the breathing circuit, meaning that the electrodes (or the surfaces thereof) will capture and absorb the CO2 present in the gas stream passing by. The electrodes may have a natural affinity for carbon dioxide and may readily react with its molecules in the gas stream, even when it is present a very low CO2 concentrations (down to the roughly 400 parts per million currently found in the atmosphere). The whole system operates at room temperature and normal pressure. The electrodes can be coated with a polymer, containing (anthra)quinone and composited with carbon nanotubes. The reverse reaction will take place while discharging.

[0026] According to an embodiment, the electrochemical plates comprise of one or more active coated electrodes, one or more counter electrodes and a separator between each active and counter electrode respectively. In an embodiment, the active electrodes and counter electrodes are placed or separated far enough from each other, such that a separator in between them is no longer necessary. In an embodiment, the complete electrochemical cell consists of an active electrode (or stack of electrodes), a counter electrode and/or a separator (depending on mounting position). By means of example, a graphene sheet can be used as counter electrode. The system can work at virtually any CO2 concentration level, even down to the roughly 400 parts per million currently found in the atmosphere.

[0027] The canister containing the electrodes can be placed or located in the breathing system on the inspiratory side, as well as the expiratory side.

[0028] The number of electrode plates or the total electrode surface (e.g. given by a stack of electrodes) used will determine the capacity of the CO2 absorbing. According to an embodiment, the distance/openings between the different plates (or 1 plate in the form of honeycomb) is between 0.8 mm and 5.4 mm.

[0029] With the present invention, a reusable system for CO2 removal can be provided for at least 2000 charging-discharging cycles, with less than 30% efficiency loss of that time. The full assembly of the system, meaning all parts, subparts including the materials they are made of, being not only reusable, but is moreover autoclavable and biocompatible for use with humans. By means of example, materials such as Makralon 2458, and Valox Resin HX420HP are applicable. There is no need of daily or weekly replacement, as the system can be charged and discharged for e.g. 5000 charging-discharging cycles with less than 30% efficiency loss. Having such amount of charging-discharging cycles, the system in accordance with the invention is much more sustainable, and has a significant life time as compared to the art.

[0030] The electrodes or stack of electrodes can be mounted in a container or canister, with sufficient distance between the electrodes, such that the breathing gasses can pass without causing more than 1 cm H2O pressure at a flow of 60 litres/min.

[0031] The canister or container for CO2 removal can be placed in the circle system (on inspiratory side or expiratory side), as an add on by means of e.g. 22 mm Male connector output, and 22 mm Female connector input. The CO2 removal system in accordance with the invention can also be mounted into the existing absorber canister of the respective manufacturer.

[0032] According to an embodiment, an existing canister of anaesthesia arrangement or workstation can be used (or new one made compatible), comprising the CO2 removal system in accordance with the invention, such that this CO2 removal system can be connected at same position of current soda lime canister.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 illustrates schematically a device 10 for CO2 removal from a gas stream 60, suitable for use in a breathing system, part of an anaesthesia arrangement. The device comprises a holder 20, adapted for fitting in the breathing system and a container 30 for CO2 removal from a gas stream 60, adapted for fitting in said holder. The container 30 removes CO2 from the gas stream 60 passing through, based on an electro-charging and discharging method. For enabling this, the container 30 in FIG. 1 comprises a plate 40, e.g. an electrochemical plate, comprising of electrodes 50, amongst which for example an active electrode 70 and a counter electrode 80, being separated from each other by means of a dielectric or isolating separator 90. The charging of the device 10 for absorbing CO2 from the gas steam 60 takes place when charging the active electrode 70 by means of providing electricity there through. According to an embodiment, the surface of the active electrode 70 is provided with material, e.g. a polymer, for attracting CO2. For the electricity provided, one may use for instance voltages of 1-3V. Discharging of the device 10 occurs when the electricity going through the active electrode changes polarity, and thus the CO2 flow is reversed, i.e. instead of CO2 being attracted by the active electrode 70, the CO2 is now being repelled.

[0034] FIGS. 2 shows a further embodiment of the device of FIG. 1, wherein two plates 40 comprising electrodes 50 are drawn, adapted for absorbing CO2 when the device 10 being charged and releasing CO2 when the device 10 is discharged. Between the plates 40, or the electrodes 50 thereof, a distance d is provided. The distance d between the plates 40 plays a role in relation to the pressure requirements for given nominal rates of the gas stream 60 passing between the plates 40, or the electrodes 50 thereof. The distance d between the plates 40 is for example 2 mm, with a minimum of 14 mm total distance available within the container 30 or canister. According to an embodiment (not shown), by means of example 6 to 8 plates 40 could be provided at 2 mm distance from each other within a single container 30. Pressure resistance on the inspiratory side of the canister, may be up to 0.9 cm H2O at peak flow between 20 to 65 litres a minute. With active canister in the breathing system, resistance test of the complete system, including the inventive canister, complies to MDR standards (total maximum resistance lower than 6 cm H2O). The canister can be put on the inspiratory side of the circle anaesthesia rebreathing system, as well as on the expiratory side. Total content of the canister may be for example 1.8 litre (but can be changed to other sizes as well). Pressure in the circuit (and the absorber device) may be between 0 to 120 cm H2O, without any influence on the functionality of the CO2 absorption. The complete canister set is autoclavable, e.g. 134° c. steam sterilization, 8 minutes cycle.

[0035] FIG. 3 shows schematically the electricity 120 being provided to the device 10 of FIG. 1, using means 100 being for example an electrically conducting cable or wire. The means 100 is on one hand connected to the container 30 within the holder 20 of the device 10. More in particular (not shown), the means 100 is connected to the electrodes 50, e.g. the active electrode 70 of the plate 40 for charging the electrodes 50 thereof. On the other hand, the means 100 is connected to a power supply, and an electronic means 110 such as an electronic circuit including e.g. an on-off switch for controlling the electro-charging operation of the device 10.

[0036] FIG. 4 illustrates an exemplary embodiment of part of the device for CO2 removal in accordance with the invention. A plate 200 is defined by electrodes, in particular an active electrode 210, on the outer side of the plate 200, and a counter electrode 220, on the inner side of the plate 200. The electrodes 210, 220 are separated from each other by a separator 230 having an electrical isolating function. Means 240 e.g. electrical cables or wires, for providing electricity 250 to the active electrodes 210 and/or the counter electrode 220 are foreseen. FIG. 4 also illustrates the two modes of operating for the embodiment wherein in a first mode, depicted in FIG. 4 (a) one provides electricity of a first polarity to charge, and thus removing CO2 from the gas stream wherein the device is immersed, while the CO2 is captured by the active electrodes 210 of the plate 200 and for example being absorbed onto their outer surfaces. The first polarity is indicated by means of the arrow next to e−. A second mode is depicted in FIG. 4 (b). The device is now removed from the gas stream, as for instance being saturated by CO2, and hence ready to be discharged out of the breathing system. Here electricity 250 is provided of a second polarity being different or reverse of the first policy, as indicated by means of reverse arrow next to e−. With this second polarity of electricity 250, the device is now discharged and hence CO2 stored in the device (as being captured thereby) is being released.

[0037] FIG. 5 illustrates the use of the invention in a breathing system context. It is worth emphasizing that the holder or container, also called canister in the field, is or can be provided with suitable connectors of different types (male, female) with typical dimensions of 22 mm diameter. According to this embodiment, the CO2 removal device is placed at the inspiratory side, although it could also be provided at the expiratory side.

[0038] According to an embodiment (not shown) the breathing system comprises of at least two CO2 removal devices in accordance with the invention. While one of those devices is switched on for charging, the other one could simultaneously be switched off for charging, and e.g. switched on for discharging. This way, the containers or canisters can alternatingly charge and discharge in parallel, and in a synchronous manner, meaning while one is charging, the other one is discharging at the same time. This time could be for instance one day (or 24 hours) while also depending on the capacity of the canister for CO2 absorption, and hence depending on the amount of CO2 concentration present or captured by the canister after one day. Moreover, the more CO2 in the breathing system, the more needs to and will be captured and absorbed by the CO2 removal device.

[0039] It is further noted that, in case only one single CO2 removal device is used in the breathing system, the operational settings may be such that discharging goes faster than charging. In other words, it would probably be desirably then, that the charging on-status of the CO2 removal device is much longer than the off-status when discharging can take place, and hence not much time is lost or spent during the discharging operation.