PASSIVE GAS MIXER WITH A HOLLOW SCREW

Abstract

A gas mixer (100), to which a first gas and a second gas are fed, mixes the two fed gases to form a gas mixture. A helical component (2) is arranged in an interior of an outer component (5). A helical mixing cavity (20) is formed between the outer component and the helical component (2). An additional mixing volume (6) is located in the interior of the outer component (5) or in the interior of the helical component (2). One gas is sent through a first feed line (31) to the helical mixing cavity (20), and the other gas is sent through a second feed line (32) to the additional mixing cavity (6). A gas mixture discharge line (40) discharges the produced gas mixture from the helical mixing cavity (20).

Claims

1. A gas mixer configured to mix a first gas and a second gas to form a gas mixture, the gas mixer comprising: an outer component; a helical component located in an interior of the outer component, an outer circumference of the helical component being in fluid-tight contact with an inner wall of the outer component; a helical mixing cavity formed between the outer component and the helical component; an additional mixing cavity formed in an interior of the helical component or in the interior of the outer component or in both the interior of the helical component and the interior of the outer component; a radial duct connecting the additional mixing cavity to the helical mixing cavity; a helical mixing cavity fluid connection of the helical mixing cavity with one of a feed line for the first gas and a feed line for the second gas; an additional mixing cavity fluid connection of the additional mixing cavity with another of the feed line for the first gas and the feed line for the second gas; and a discharge fluid connection of the helical mixing cavity or the additional mixing cavity with a gas mixture discharge line for discharging the formed gas mixture.

2. A gas mixer in accordance with claim 1, wherein the gas mixer further comprises: an outlet-side component; an inner outlet cavity in an interior of the outlet-side component, wherein the outer component fluid-tightly encloses the outlet-side component; an inner outlet cavity fluid connection of the inner outlet cavity with the gas mixture discharge line; and an inner outlet cavity radial duct connecting the helical mixing cavity or the additional mixing cavity to the inner outlet cavity.

3. A gas mixer in accordance with claim 2, further comprising: a gas sample cavity formed between the outer component and the outlet-side component; a sample cavity radial duct connecting the inner outlet cavity to the gas sample cavity; a sensor for testing the formed gas mixture; a gas sample cavity fluid connection of the gas sample cavity with the sensor.

4. A gas mixer in accordance with claim 3, wherein: the sensor comprises a concentration sensor configured to measure an indicator for a concentration of a gas in a gas mixture in the inner outlet cavity; or the sensor comprises a volume flow sensor configured to measure an indicator for a volume per unit of time of a gas mixture, which flows through the inner outlet cavity; or the sensor comprises a temperature sensor configured to measure an indicator for a temperature of a gas mixture in the inner outlet cavity; or the sensor comprises any combination of a concentration sensor configured to measure an indicator for a concentration of at least one gas in a gas mixture in the inner outlet cavity, and a volume flow sensor configured to measure an indicator for a volume per unit of time of a gas mixture, which flows through the inner outlet cavity, and a temperature sensor configured to measure an indicator for a temperature of a gas mixture in the inner outlet cavity.

5. A gas mixer in accordance with claim 1, wherein the additional mixing cavity is formed in the interior of the helical component.

6. A gas mixer in accordance with claim 1, wherein the additional mixing cavity is formed in the interior of the outer component.

7. A gas mixer in accordance with claim 1, further comprising a further additional mixing cavity, wherein: the additional mixing cavity is a first additional mixing cavity and the further additional mixing cavity is a second additional mixing cavity; the first additional mixing cavity is formed in the interior of the helical component; and the second additional mixing cavity is formed in the interior of the outer component.

8. A gas mixer in accordance with claim 1, wherein: the gas mixer extends along a longitudinal axis; and an extension of the helical mixing cavity or an extension of the additional mixing cavity or the extension of the helical mixing cavity and the extension of the additional mixing cavity is smaller than the extension of the outer component along the longitudinal axis of the gas mixer.

9. A gas mixer in accordance with claim 1, further comprising: an inlet-side component; an inlet cavity formed between the inner wall of the outer component, the inlet-side component and the helical component; an inlet cavity fluid connection of the inlet cavity with the helical mixing cavity or with the additional mixing cavity or with both the helical mixing cavity and with the additional mixing cavity; and an inlet cavity fluid connection of the inlet cavity with the feed line for the first gas or with the feed line for the second gas.

10. An arrangement comprising: a first feed line configured to feed a first gas; a second feed line configured to feed a second gas; a gas mixture discharge line to discharge a gas mixture; a gas mixer configured to mix the first gas and the second gas to form the gas mixture, the gas mixer comprising: an outer component; a helical component located in an interior of the outer component, an outer circumference of the helical component being in fluid-tight contact with an inner wall of the outer component; a helical mixing cavity formed between the outer component and the helical component; an additional mixing cavity formed in an interior of the helical component or in the interior of the outer component; a radial duct connecting the additional mixing cavity to the helical mixing cavity; a helical mixing cavity fluid connection of the helical mixing cavity with the feed line for the first gas; an additional mixing cavity fluid connection of the additional mixing cavity with the feed line for the second gas; and a discharge fluid connection of the helical mixing cavity or the additional mixing cavity with the gas mixture discharge line for discharging formed the gas mixture.

11. An arrangement according to claim 10, in combination with a medical device to provide a system for ventilation of a patient, wherein the medical device is configured to feed the gas mixture formed by the gas mixer to a patient-side coupling unit connected to the patient; the gas mixture discharge line establishes a fluid connection to the medical device; the arrangement is configured to deliver the first gas to the gas mixer through the first feed line and to deliver the second gas to the gas mixer through the second feed line; the gas mixer is configured to mix the delivered first gas and the delivered second gas to form the gas mixture; and the arrangement or a delivery unit of the medical device is configured to deliver the gas mixture formed by the gas mixer through the gas mixture discharge line to the medical device.

12. An arrangement in accordance with claim 11, wherein: the first gas is a carrier gas; the second gas comprises anesthetic; and the medical device is configured to feed to the patient the gas mixture to anesthetize the patient.

13. An arrangement according to claim 10, wherein the gas mixer further comprises: an outlet-side component; an inner outlet cavity in an interior of the outlet-side component, wherein the outer component fluid-tightly encloses the outlet-side component; an inner outlet cavity fluid connection of the inner outlet cavity with the gas mixture discharge line; and an inner outlet cavity radial duct connecting the helical mixing cavity or the additional mixing cavity to the inner outlet cavity.

14. An arrangement according to claim 13, further comprising: a gas sample cavity formed between the outer component and the outlet-side component; a sample cavity radial duct connecting the inner outlet cavity to the gas sample cavity; a sensor for testing the formed gas mixture; a gas sample cavity fluid connection of the gas sample cavity with the sensor.

15. An arrangement in accordance with claim 14, wherein: the sensor comprises a concentration sensor configured to measure an indicator for a concentration of at least one gas in a gas mixture in the inner outlet cavity; or the sensor comprises a volume flow sensor configured to measure an indicator for a volume per unit of time of a gas mixture, which flows through the inner outlet cavity; or the sensor comprises a temperature sensor configured to measure an indicator for a temperature of a gas mixture in the inner outlet cavity; or the sensor comprises any combination of a concentration sensor configured to measure an indicator for a concentration of at least one gas in a gas mixture in the inner outlet cavity, and a volume flow sensor configured to measure an indicator for a volume per unit of time of a gas mixture, which flows through the inner outlet cavity, and a temperature sensor configured to measure an indicator for a temperature of a gas mixture in the inner outlet cavity.

16. An arrangement according to claim 10, further comprising a further additional mixing cavity, wherein: the additional mixing cavity is a first additional mixing cavity and the further additional mixing cavity is a second additional mixing cavity; the first additional mixing cavity is formed in the interior of the helical component; and the second additional mixing cavity is formed in the interior of the outer component.

17. An arrangement according with claim 10, wherein: the gas mixer extends along a longitudinal axis; and an extension of the helical mixing cavity or an extension of the additional mixing cavity or the extension of the helical mixing cavity and to extension of the additional mixing cavity is smaller than the extension of the outer component along the longitudinal axis of the gas mixer.

18. An arrangement according to claim 10, further comprising: an inlet-side component; an inlet cavity formed between the inner wall of the outer component, the inlet-side component and the helical component; an inlet cavity fluid connection with the helical mixing cavity or with the additional mixing cavity or with both the helical mixing cavity and with the additional mixing cavity; and an inlet cavity fluid connection with the feed line for the first gas or with the feed line for the second gas.

19. A process comprising the steps of: providing an arrangement comprising: a first feed line configured to feed a first gas; a second feed line configured to feed a second gas; a gas mixture discharge line to discharge a gas mixture; and a gas mixer configured to mix the first gas and the second gas to form the gas mixture, the gas mixer comprising: an outer component; and a helical component located in an interior of the outer component, an outer circumference of the helical component being in fluid-tight contact with an inner wall of the outer component; a helical mixing cavity formed between the outer component and the helical component; an additional mixing cavity formed in an interior of the helical component or in the interior of the outer component; a radial duct connecting the additional mixing cavity to the helical mixing cavity; a helical mixing cavity fluid connection of the helical mixing cavity with the feed line for the first gas; an additional mixing cavity fluid connection of the additional mixing cavity with the feed line for the second gas; and a discharge fluid connection of the helical mixing cavity or the additional mixing cavity with the gas mixture discharge line for discharging the formed gas mixture; and supplying the formed gas mixture from the gas mixer, via the gas mixture discharge line to a ventilator, wherein the ventilator is configured for ventilation of a patient.

20. A process for manufacturing a gas mixer configured to mix a first gas and a second gas to form a gas mixture, the gas mixer comprising: an outer component; a helical component located in an interior of the outer component, an outer circumference of the helical component being in fluid-tight contact with an inner wall of the outer component; a helical mixing cavity formed between the outer component and the helical component; an additional mixing cavity formed in an interior of the helical component or in the interior of the outer component or in both the interior of the helical component and the interior of the outer component; a radial duct connecting the additional mixing cavity to the helical mixing cavity; a helical mixing cavity fluid connection of the helical mixing cavity with one of a feed line for the first gas and a feed line for the second gas; an additional mixing cavity fluid connection of the additional mixing cavity with another of the feed line for the first gas and the feed line for the second gas; and a discharge fluid connection of the helical mixing cavity or the additional mixing cavity with a gas mixture discharge line for discharging the formed gas mixture, the process comprising the step of: providing a computer program, which can be executed on a computer and when executed prompts the computer to actuate a 3D printer such that the actuated 3D printer produces one or more of the outer component and the helical component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In the drawings:

[0050] FIG. 1 is a schematic view showing the ventilation of a patient by means of a ventilator;

[0051] FIG. 2 is a schematic view showing a system for anesthetizing a patient with the use of a ventilator;

[0052] FIG. 3 is a cross-sectional view of the gas mixer according to a first embodiment of the present invention, wherein the longitudinal axis of the gas mixer is located in the drawing plane, as well as a front view, wherein the longitudinal axis is at right angles to the drawing plane;

[0053] FIG. 4 is a view of the gas mixer according to the first embodiment from one of two mutually opposite viewing directions and another view according to the first embodiment from another of the two mutually opposite viewing directions, wherein the longitudinal axis is located in the drawing plane;

[0054] FIG. 5 is a perspective view showing portions of the gas mixer from FIG. 3 and from FIG. 4;

[0055] FIG. 6 is a schematic view showing the gas mixer from FIG. 3 through FIG. 5 as well as two feed lines and a discharge line, wherein the longitudinal axes of the gas mixer and of the lines are located in the drawing plane;

[0056] FIG. 7 is a cross sectional view of an example of two gases being mixed in the helical mixing cavity between the helical component (screw) and the housing if gas 2 is under a higher pressure than gas 1;

[0057] FIG. 8 is a cross-sectional view of an example of two gases being mixed in the additional mixing cavity in the screw if gas 1 is under a higher pressure than gas 2;

[0058] FIG. 9 is a cross-sectional side view showing a second embodiment of the gas mixer; and

[0059] FIG. 10 is a cross-sectional side view showing a third embodiment, which combines aspects of the first embodiment and the second embodiment.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0060] Referring to the drawings, the present invention is used in the exemplary embodiment in a gas mixer 100 according to the present invention, wherein the gas mixer 100 produces a gas mixture, which is fed to a ventilator. The ventilator ventilates a patient. In one embodiment, the ventilator belongs to a system, which anesthetizes the patient.

[0061] FIG. 1 shows schematically how a ventilator 50 ventilates a patient P. The ventilator 50 delivers a quantity of a gas mixture G during each ventilation stroke to a patient-side coupling unit 43, which is connected to the patient P, for example, to a breathing mask on the face or to a tube in the body of the patient P. The gas mixture G consisting of breathing air (acting as the first gas G1) and oxygen (O2, acting as the second gas G2) is produced in the example shown in FIG. 1.

[0062] A supply port 61.1 in a wall W provides breathing air under overpressure, and a supply port 61.2 provides oxygen (O2) under overpressure. It is also possible that the first gas G1 and/or the second gas G2 are provided from a compressed air cylinder. A first feed line 31 sends the breathing air G1 from the supply port 61.1 to the gas mixer 100 according to the present invention, and a second feed line 32 sends the oxygen G2 from the supply port 61.2 to the gas mixer 100. A proportional valve or on-off valve 25.1 in the first feed line 31 changes the volume flow of breathing air, and a proportional valve or on-off valve 25.2 in the second feed line 32 changes the volume flow of oxygen. A signal-processing control device (controller), not shown, is preferably capable of actuating the two valves 25.1, 25.2 in order to achieve a respective desired volume flow. The gas mixer 100 produces a gas mixture G from breathing air and oxygen. This gas mixture G flows through a gas mixture discharge line 40 to the ventilator 50 and farther to the patient-side coupling unit 43.

[0063] FIG. 1 shows, furthermore, a system 200 for the assisted ventilation of the patient P, wherein the system 200 is in a fluid connection with the patient-side coupling unit 43. The system 200 comprises the ventilator 50, an arrangement 110 comprising the gas mixer 100 and the proportional valves 25.1 and 25.2 as well as a plurality of lines 31, 32, 40.

[0064] FIG. 2 shows an application in which the patient P is not only ventilated, but is additionally also anesthetized. Identical reference numbers have the same meanings as in FIG. 1. A gas is added to a carrier gas, the carrier gas being or containing air, O2 and/or N2O and the added gas being or containing anesthetic (one or more anesthetic agent—or at least one anesthetic agent). The anesthetic is especially an isoflurane, sevoflurane, halothane or desflurane. The added gas may contain an additional component, especially oxygen or breathing air, in addition to anesthetic. This gas mixture of the carrier gas and the gas containing anesthetic is used in the application according to FIG. 2 to anesthetize the patient P.

[0065] The carrier gas G1 acts in this application as the first gas, and the gas G2 containing anesthetic acts as the second gas. “Anesthetic” G2 will be referred to below for short. The mixture of the carrier gas G1 and anesthetic G2, which is produced by the gas mixer 100, acts as the produced gas mixture G.

[0066] FIG. 2 schematically shows a system 210, which is configured to anesthetize the patient P. Identical reference numbers have the same meaning as in FIG. 1. The ventilator 50 receives from the gas mixer 100 a gas mixture G, which contains oxygen and anesthetic (at least one anesthetic agent). The ventilator 50 carries out a sequence of ventilation strokes and delivers during each ventilation stroke a gas mixture G consisting of the carrier gas G1 with oxygen and the added gas G2 with anesthetic through a gas mixture line arrangement 62 to the patient-side coupling unit 43. A closed patient-side ventilation circuit is established between the patient-side coupling unit 43 and the ventilator 50, and the gas mixture line arrangement 62 comprises a lumen for the inhalation and a lumen for the exhalation. The ventilator 50 keeps the ventilation circuit running in this application by means of a pump, a blower or a piston. The exhaled breathing air flows back to the ventilator 50, and the ventilator 50 processes this breathing air. Since a circuit is established, anesthetic does not escape into the surrounding area.

[0067] A gas mixture discharge line 40 sends the gas mixture G from the gas mixer 100 according to the present invention to an anesthesia breathing circuit in the ventilator 50. In one embodiment, the ventilator 50 sucks in the gas mixture G through the gas mixture discharge line 40.

[0068] The gas mixer 100 is supplied with the carrier gas G1 by means of a carrier gas feed line 31. A mixer 70 for carrier gas produces the carrier gas G1 from a plurality of components, in the example from oxygen, breathing air and N2O, and it feeds same into the carrier gas feed line 31. It is possible that a valve (not shown) 25.1 changes the volume flow through the carrier gas feed line 31. The carrier gas G1 is preferably under an overpressure relative to the ambient pressure in the carrier gas feed line 31. A supply port 61 in a wall W supplies the carrier gas mixer 70 with the carrier gas components breathing air, O2 and N2O. The carrier gas may, of course, also be composed of additional and/or other components. It is also possible that breathing air is used as carrier gas and no carrier gas mixer 70 is necessary.

[0069] The gas mixer 100 is supplied with anesthetic G2 in the gaseous form by means of an anesthetic feed line 32. Gaseous anesthetic G2 is preferably under an overpressure relative to the ambient pressure in the anesthetic feed line 32. It is possible that a valve 25.2 changes the volume flow of anesthetic G2 through the anesthetic feed line 32.

[0070] In one embodiment, the anesthetic feed line 32 feeds pure anesthetic to the gas mixer 100. In another embodiment, which is shown schematically in FIG. 2, the anesthetic feed line 32 sends a mixture of anesthetic and pure oxygen to the gas mixture of anesthetic and pure oxygen to the gas mixer 100. A bypass line 34 bypasses the carrier gas mixer 70 and sends the oxygen from the supply port 61 directly to the anesthetic feed line 32.

[0071] In the embodiment according to FIG. 2, an anesthetic dispenser 55 with a heater 56 produces gaseous anesthetic G2 from liquid anesthetic G2, which is fed to the anesthetic dispenser 55 via a feed line 41. It is possible that the anesthetic dispenser 55 produces gaseous anesthetic G2 by evaporation or vaporization. It is also possible that the bypass line 34 sends oxygen to the anesthetic dispenser 55 and the anesthetic dispenser 55 feeds gaseous anesthetic into the oxygen.

[0072] In addition, FIG. 1 and FIG. 2 schematically show an arrangement 110, which comprises in the example shown a gas mixer 100, the two feed lines 31 and 32 as well as the gas mixture discharge line 40.

[0073] It is possible that the gas mixer 100 or the entire arrangement 110 is arranged in the interior of the ventilator 50. The arrangement 110 is shown in FIG. 1 and FIG. 2 for illustration outside of the ventilator 50. The arrangement 110 is a part of the system 200 or 210.

[0074] The gas mixer 100 according to the exemplary embodiment is a passive mechanical component, i.e., the gas mixer 100 comprises no component moving during the regular operation and also no component through which electrical current flows. Aside from seals, the gas mixer 100 comprises rigid components.

[0075] A desired concentration of oxygen in the gas mixture G is predefined in the exemplary embodiment according to FIG. 1. A concentration sensor 15 shown schematically measures an indicator of the actual concentration of oxygen G2 in the gas mixture G, which is produced by the gas mixer 100. A desired concentration of anesthetic G2 in the gas mixture G is predefined in the exemplary embodiment according to FIG. 2. A concentration sensor 15 shown schematically measures an indicator of the actual concentration of anesthetic G2 in the gas mixture G.

[0076] The concentration sensor 15 is arranged downstream of the gas mixer 100 and will be described farther below. In order to reduce a deviation between the desired concentration and the measured actual concentration of a component of the gas mixture G, the volume flow of a gas G1 and/or G2 to the gas mixer 100 can be changed. In one embodiment, a signal-processing control device, not shown, controls at least one of the valves 25.1 or 25.2 or a valve in a line of the anesthesia system 210 in order to change the volume flow of a gas to the gas mixer 100 and hence the composition or the volume flow of the gas mixture G. The control device preferably carries out a regulation with the desired concentration and/or with the desired volume flow as the command variable. The regulation target is to make the actual concentration or the actual volume equal to the desired concentration or to the desired volume flow.

[0077] Liquid anesthetic G2 flows from an anesthetic tank 51 into the feed line 41 to the anesthetic dispenser 55. The gas, which is formed in the anesthetic tank 51 above liquid anesthetic G2, is under an overpressure relative to the ambient pressure. A supply port 60 in the wall W feeds compressed air or another gas, which is under an overpressure, into a supply line 42, so that an overpressure is admitted into the anesthetic tank 51 relative to the ambient pressure.

[0078] In order to refill liquid anesthetic G2 in the anesthetic tank 51, a cylinder 54 containing liquid anesthetic G2 is attached to a closure 53 in a fluid-tight manner, the closure 53 is opened, and liquid anesthetic G2 flows from the cylinder 54 obliquely downward through the feed line 52 into the anesthetic tank 51.

[0079] FIG. 3 through FIG. 6 show a first embodiment of the gas mixer 100 from different viewing directions. The following description pertains to the arrangement according to FIG. 2, in which a gas mixture G comprising anesthetic and a carrier gas is fed to the patient P and the patient P is anesthetized thereby. The gas mixer 100 described below can also be used in a corresponding manner to feed a gas mixture to the ventilator, in which case the ventilator 50 ventilates the patient P with this gas mixture without anesthetizing patient P, i.e., for the assisted ventilation according to FIG. 1. The gas mixer 100 can also be used to provide a gas mixture G, which the patient P inhales by means of his intrinsic respiratory muscles, i.e., without an assisted ventilation.

[0080] The gas mixer 100 has approximately the shape of a cylinder and extends along a longitudinal axis L, which is located in the drawing planes of FIG. 3, FIG. 4 and FIG. 6 and is directed obliquely on the drawing plane of FIG. 5. As can be seen in FIG. 6, the carrier gas G1 is fed to the gas mixer 100 in the exemplary embodiment via the carrier gas feed line 31, which is arranged laterally relative to the longitudinal axis L, and anesthetic G2 is fed via the centrally arranged anesthetic feed line 32. The longitudinal axis of the carrier gas feed line 31 is directed at right angles to the longitudinal axis L of the gas mixer 100. The longitudinal axes of the anesthetic feed line 32 and of the gas mixture discharge line 40 are identical to the longitudinal axis L. The gas mixture G leaves the gas mixer 100 via the centrally arranged gas mixture discharge line 40. A gas sample from the gas mixture G produced is delivered from the gas mixture discharge line 40 to the concentration sensor 15 and is fed again into the gas mixture discharge line 40. This preferably happens continuously.

[0081] The gas mixer 100 extends along the longitudinal axis L and comprises the following components, which are arranged—along the longitudinal axis L and seen in a flow direction from the anesthetic feed line 32 to the gas mixture discharge line 40—one after another, i.e., from left to right in FIG. 3 and FIG. 4 and FIG. 6: [0082] a hollow inlet cylinder 1, which acts as the inlet-side component, [0083] a hollow screw 2, which acts as the helical component, [0084] a neck 3, and [0085] a hollow outlet cylinder 4.

[0086] The neck 3 and the outlet cylinder 4 act together as the outlet-side component.

[0087] Each component 1, 2, 3, 4 as well as each line 31, 32, 40 is manufactured from a respective material that is resistant to each anesthetic agent and/or other gas being considered in the gas mixture. The material or at least one material is, for example, a hard plastic, especially a polyether ether ketone (PEEK) or another Polyaryletherketon (PEAK).

[0088] A tubular outer component in the form of a housing 5 encloses these four components 1 through 4. The outer component 5 preferably has a circular or elliptical cross section. The housing 5 is also manufactured from a material that is resistant to each anesthetic agent/other gas being considered as well as to the cleaning agents used in a medical setting. The inner wall of the housing 5 is in contact with the screw 2 in a fluid-tight manner and with the outlet cylinder 4 in a fluid-tight manner. The outside diameter of the inlet cylinder and the outside diameter of the neck 3 are smaller than the internal diameter of the housing 5. A ring-shaped inlet cavity 21, which encloses the inlet cylinder 1 and preferably has a rectangular cross section in a plane extending at right angles to the longitudinal axis L, is therefore formed in the housing 1.

[0089] A helical mixing cavity 20 is formed between the circular groove of the screw 2 and the inner wall of the housing 5. This helical mixing cavity 20 extends along a longitudinal axis, which is arranged parallel to the longitudinal axis L of the gas mixer 100, also encloses the neck 3 and is defined by the outlet cylinder 4. No cavity is formed between the housing 5 and the outlet cylinder 4, because the housing 5 is in contact with the outlet cylinder 4 in a fluid-tight manner.

[0090] A centrally arranged, additional mixing cavity 6 has the shape of a column, is passed through the entire inlet cylinder 1 and through a part of the screw 2, extends along a longitudinal axis, which is identical or parallel to the longitudinal axis L of the gas mixer 100, and ends in the end E. The column-shaped mixing cavity 6 preferably has the shape of a round or elliptical cylinder or truncated cone, but it may also have a polygonal cross-sectional area with n>=3 [sides]. A distance d occurs between the end E and the neck 3. The column-shaped mixing cavity 6 preferably encloses an area of the screw 2, whose length equals between 40% and 90%, especially preferably between 60% and 70%, of the total length of the screw 2 along the longitudinal axis L. The anesthetic feed line 32 opens into this mixing cavity 6 in a fluid-tight manner and axially.

[0091] An outlet cavity 8, which preferably has the shape of a column, is passed through the neck 3 and the entire outlet cylinder 4. This outlet cavity 8 opens into the gas mixture discharge line 40 in a fluid-tight manner. The screw 2 blocks the direct path from the additional mixing cavity 6 to the outlet cavity 8.

[0092] The two cylinders 1 and 4, the neck 3 and the two cavities 6 and 8 are positioned rotationally symmetrically to the longitudinal axis L of the gas mixer 100. The screw 2 is arranged around this longitudinal axis L. The central axis of the screw 2 is preferably identical to the longitudinal axis L.

[0093] A ring-shaped gap 7 is recessed into the outer wall of the outlet cylinder 4 and forms a gas sample cavity. A line 33, which leads to the concentration sensor 15, is connected to this gap 7. In addition, a circular groove is recessed in the outer wall of the outlet cylinder 4 for a sealing ring 9.

[0094] A plurality of radial ducts 10 in the screw 2 connect the column-shaped mixing cavity 6 to the helical mixing cavity 20. The radial duct 10, which is the last duct when viewed in the flow direction, adjoins the end E of the additional mixing cavity 6, so that no dead space is formed in the column-shaped mixing cavity 6. A plurality of radial ducts (inner outlet cavity radial ducts) 12 in the neck 3 connect the column-shaped mixing cavity 6 to the outlet cavity 8. The ducts 12 have larger cross-sectional areas than do the ducts 10, and each duct 12 with its cross-sectional area preferably occupies the total length of the neck 3 along the longitudinal axis L, so that no dead space is formed in the outlet cylinder 4. The two cavities 6 and 8 are in a fluid connection with one another via the ducts 10 and 12 as well as via the helical mixing cavity 20.

[0095] A plurality of radial ducts (sample cavity radial ducts) 11 in the outlet cylinder 4 connect the outlet cavity 8 to the ring-shaped gap 7. As a result, the concentration sensor 15 is in a fluid connection with the outlet cavity 8, through which the gas mixture G flows.

[0096] An angle between 80° and 100° and especially preferably a right angle is preferably formed between the longitudinal axis 1 of the gas mixer 100 and the radial ducts 10, 11, 12.

[0097] Both the carrier gas G1 and anesthetic G2 are under an overpressure relative to the ambient pressure in the exemplary embodiment and they flow as a result to the gas mixer 100.

[0098] The carrier gas G1 flows through the laterally arranged carrier gas feed line 31 into the inlet cavity 21 and from there into the helical mixing cavity 20. The screw 2 and the housing 5 force the carrier gas G1 to move along a helical path through the helical mixing cavity 20, and this path ends at a front wall of the outlet cylinder 4. Anesthetic G2 flows through the centrally arranged feed line 32 into the column-shaped mixing cavity 6.

[0099] FIG. 7 and FIG. 8 illustrate as an example how the two gases G1 and G2 are mixed with one another in the interior of the gas mixer 100. The longitudinal axis L is at right angles to the drawing planes of FIG. 7 and FIG. 8.

[0100] In the example according to FIG. 7, anesthetic G2 is under a higher pressure than the carrier gas G1. Anesthetic G2 therefore flows from the column-shaped mixing cavity 6 through the radial ducts 10 and into the helical mixing cavity 20. The two gases G1 and G2 are mixed with one another in the helical mixing cavity 20 and form the gas mixture G there. Since the outlet cylinder 4 defines the cavity 20, the gas mixture G is pressed through the ducts 12 into the outlet cavity 8. The gas mixture G flows from the outlet cylinder 8 into the gas mixture discharge line 40.

[0101] By contrast, the carrier gas G1 is under a higher pressure than anesthetic G2 in the example according to FIG. 8. The carrier gas G1 flows therefore from the helical mixing cavity 20 through the radial ducts 10 and into the column-shaped mixing cavity 6. The two gases G1 and G2 are mixed with one another in the column-shaped mixing cavity 6 and form a gas mixture G there. The pressure in the column-shaped mixing cavity 6 rises, and the gas mixture G leaves again the additional mixing cavity 6 through radial ducts 10 and flows into the helical mixing cavity 20. The further path of the gas mixture G is the same as that described with reference to FIG. 7.

[0102] A small portion of the gas mixture G flows through radial ducts 11 into the ring-shaped gap 7 and from there to the concentration sensor 15 through the line 33. This sensor 15 measures an indicator of the actual concentration of anesthetic G2 in the gas mixture G. The quantity of the gas mixture G that was branched off as a gas sample through the ducts 11 and was sent to the concentration sensor 15 is preferably fed later again to the rest of the gas mixture G.

[0103] An angle, which is between 80° and 100°, is preferably formed between each duct 10, 11, 12 and the longitudinal axis L of the gas mixer 100. A gas G1, G2, G is therefore deflected by an angle of at most 100° when it flows through the gas mixer 100. A right angle each is formed especially preferably between each duct 10, 11, 12 and the longitudinal axis L, and the gas G1, G2, G is deflected by a right angle at the maximum.

[0104] The positions of the ducts 10 and 12 ensure in the exemplary embodiments that a dead space will not be formed either in a mixing cavity 6, 20 or in the inlet cavity 6. Such a dead space in a cavity is undesirable since gas can collect in a dead space and is not moved further as a gas outside of the dead space at all or is moved only more slowly. This could lead to a relatively poor mixing quality. The respective overpressure, under which the carrier gas G1 in the carrier gas feed line 31 and anesthetic G2 in the anesthetic feed line 32 are, as well as the construction of the gas mixer 100 do rather keep the two gases G1 and G2 as well as the gas mixture G in the gas mixer 100 steadily in motion, while the gas mixer 100 is being used. It is especially due to this fact that the gas mixer 100 according to the exemplary embodiment has achieved a mixing quality above 98% in in-house tests. “Mixing quality” is defined as the minimum and mean concentration or the quotient of the mean concentration and the maximum concentration of anesthetic G2 in the gas mixture G at a given time.

[0105] FIG. 9 shows a second embodiment of the gas mixer 100 according to the present invention. Identical reference numbers have the same meaning as in FIG. 3 through FIG. 8.

[0106] Contrary to the first embodiment, the additional mixing cavity 6 is arranged in the second embodiment in the interior of the tubular outer component 5 rather than in the interior of the screw 2. The outer component 5 is therefore thicker in the second embodiment than in the first embodiment. The screw 2 is configured in the second embodiment as a massive component, i.e., it has no cavity in the interior. The extension of the additional mixing cavity 6 is also smaller in the second embodiment than is the extension of the screw 2 or of the outer component 5. The additional mixing cavity 6 preferably has the shape of a centered tube in the second embodiment, and this tube encloses the screw 2 and the longitudinal axis of the tube is identical to the longitudinal axis L of the gas mixer 100. The additional mixing cavity 6 may, however, also have the shape of a laterally offset column or of a laterally offset tube, i.e., it cannot enclose the screw 2. The longitudinal axis of the additional mixing cavity 6 is parallel to the longitudinal axis L and is located at a spaced location from same in this embodiment.

[0107] If the additional mixing cavity 6 is oriented as a centered tube, an inlet cavity 23 in the form of a ring gap connects the carrier gas feed line 31 to the additional mixing cavity 6. If the additional mixing cavity 6 is configured as a column or as a laterally offset tube, the carrier gas feed line 31 may open directly into the additional mixing cavity 6. An inlet cavity 22 connects the anesthetic feed line 32 to the helical mixing cavity 20.

[0108] In the second embodiment according to FIG. 9, the carrier gas G1 is consequently sent into the additional mixing cavity 6, and anesthetic G2 into the helical mixing cavity 20. Just as in the first embodiment, a plurality of radial ducts 10 connect the additional mixing cavity 6 to the helical mixing cavity 20.

[0109] FIG. 10 shows a third embodiment, which is a combination of the first embodiment with the second embodiment. The gas mixer 100 according to FIG. 10 is capable of forming a gas mixture from three fed gases, for example, from [0110] a carrier gas, which is fed through the carrier gas feed line 31, [0111] anesthetic (one or more anesthetic agent), which is fed via the anesthetic feed line 32, and [0112] pure oxygen, which is fed via at least one additional feed line 35.

[0113] It is also possible that the carrier gas or the same anesthetic or another anesthetic is fed via the additional feed line 35.

[0114] The gas mixer 100 according to the third embodiment comprises two additional mixing cavities, namely, both a column-shaped mixing cavity 6.1 in the interior of the screw 2 and a tubular mixing cavity 6.2 in the interior of the tubular outer component 5. The tubular mixing cavity 6.2 encloses the hollow screw 2. The two mixing cavities 6.1 and 6.2 are two additional mixing cavities. Just as in the first embodiment, the anesthetic feed line 32 leads into the column-shaped mixing cavity 6.1. Just as in the second embodiment, the carrier gas feed line 31 leads into the tubular mixing cavity 6.2. The additional feed line or each additional feed line 35 opens into the helical mixing cavity 20.

[0115] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

[0116] 1 Inlet cylinder; it encloses the tubular additional mixing cavity 6; enclosed by the ring-shaped inlet cavity 21 [0117] 2 Screw; it encloses the inlet cavity 6, has the radial ducts 10, acts as the helical component [0118] 3 Neck between the screw 2 and the outlet cylinder 4; it has the radial ducts 12, belongs to the outlet-side component [0119] 4 Outlet cylinder; it encloses the outlet cavity 8, has the radial ducts 11, belongs to the outlet-side component [0120] 5 Tubular outer component, in the form of a housing in the first embodiment, encloses the additional mixing cavity 6 in the second embodiment and encloses the additional mixing cavity 6.2 in the third embodiment, encloses the inlet cylinder 1 and the neck 3 [0121] 6 Additional mixing cavity, enclosed by the inlet cylinder 1 and by the screw 2 or by the outer component 5; it ends at the end E [0122] 7 Ring-shaped gap in the outlet cylinder 4 [0123] 8 Outlet cavity, enclosed by the outlet cylinder 4 [0124] 9 Sealing ring, arranged in a circular groove in the outer wall of the outlet cylinder [0125] 10 Radial ducts in the screw 2; they connect the additional mixing cavity 6 or 6.2 to the cavity 20 [0126] 11 Radial ducts in the outlet cylinder 4; they connect the outlet cavity 8 to the ring-shaped gap 7 [0127] 12 Radial ducts in the neck 3; they connect the helical mixing cavity 20 to the outlet cavity 8 [0128] 15 Sensor, which measures the concentration of anesthetic G2 in the gas mixture G [0129] 20 Helical mixing cavity between the circumferential groove of the screw 2 and the housing 5, connected through the radial ducts 10 to the additional mixing cavity 6 or 6.2, enclosed by the outer component 5 in a fluid-tight manner [0130] 21 Ring-shaped inlet cavity; it connects the carrier gas feed line 31 to the helical mixing cavity 20 in the first embodiment [0131] 22 Inlet cavity; it connects the anesthetic feed line 32 to the helical mixing cavity 20 in the second embodiment [0132] 23 Ring-shaped inlet cavity; it connects the carrier gas feed line 31 to the additional mixing cavity 6 in the second embodiment and to the additional mixing cavity 6.2 in the third embodiment [0133] 25.1 Actuated proportional valve in the first feed line 31 [0134] 25.2 Actuated proportional valve in the second feed line 32 [0135] 31 First feed line for the first G1 (breathing air or carrier gas); it opens into the ring-shaped inlet cavity 21 or 23 [0136] 32 Second feed line for the second gas G2 (oxygen or anesthetic); it opens into the inner mixing cavity 6 [0137] 33 Line from the ring-shaped gap 7 to the concentration sensor 15 [0138] 34 Optional bypass line for oxygen; it bypasses the carrier gas mixer 70; opens into the anesthetic feed line 32 [0139] 35 Additional feed line; it opens into the helical mixing cavity 20 in the third embodiment [0140] 40 Gas mixture discharge line; it sends the mixture of gas 1 and gas 2 to the ventilator 50 [0141] 41 Feed line for liquid anesthetic G2; it leads from the anesthetic tank 51 to the anesthetic dispenser 55 [0142] 42 Feed line for compressed air; it leads from the compressed air port 60 to the anesthetic tank 51 [0143] 43 Patient-side coupling unit, connected to the ventilator 50 by means of the gas mixture line arrangement 62 [0144] 50 Ventilator; it receives the gas mixture G through the gas mixture discharge line 40, carries out ventilation strokes, delivers the gas mixture G through the gas mixture line arrangement 62 to the patient-side coupling unit 43 [0145] 51 Anesthetic tank; it contains anesthetic G2 in the liquid form; connected to the gas mixer 100 via the feed line 32 [0146] 52 Feed line for gaseous anesthetic; it opens into the anesthetic tank 51 [0147] 53 Closure for the feed line 52 [0148] 54 Cylinder containing liquid anesthetic [0149] 55 Anesthetic dispenser; it evaporates or vaporizes liquid anesthetic G2 and feeds gaseous anesthetic into the feed line 32 [0150] 56 Heater for the anesthetic dispenser 55 [0151] 60 Supply port for compressed air in the wall W [0152] 61 Supply port for the components of the carrier gas G1 in the wall W; it supplies the carrier gas mixer 70 [0153] 61.1 Supply port in the wall W for pressurized breathing air [0154] 61.2 Supply port in the wall W for pressurized oxygen [0155] 62 Gas mixture line arrangement from the ventilator 50 to the patient P; it delivers the gas mixture G to the patient P [0156] 70 Mixer for carrier gas; it produces the carrier gas G1 and feeds it into the carrier gas feed line 31 [0157] 100 Gas mixer according to the present invention; it receives a carrier gas G1 from the carrier gas feed line 31 and anesthetic G2 from the anesthetic feed line 32 and it optionally feeds a third gas from the feed line 35; it sends a gas mixture G into the gas mixture discharge line 40 [0158] 110 Arrangement comprising the gas mixer 100, the feed lines 31 and 32, the gas mixture discharge line 40 and the proportional valves 25.1 and 25.2 [0159] 200 System for the assisted ventilation of the patient P; it comprises the ventilator 50 and the arrangement 110 [0160] 210 System for anesthetizing the patient P; it comprises the ventilator 50, the anesthetic dispenser 55, the anesthetic tank 51, the carrier gas mixer 70 and the arrangement 110 [0161] D Distance between the end E and the neck 3 [0162] E End of the additional mixing cavity 6 in the screw 2 [0163] G Gas mixture consisting of gas 1 and gas 2; produced by the gas mixer 100; it flows through the gas mixture discharge line 40 [0164] G1 Gas 1: Breathing air or carrier gas [0165] G2 Gas 2: Oxygen or anesthetic L Longitudinal axis of the gas mixer 100 [0166] P Patient, who is ventilated by the ventilator 50 and is optionally anesthetized; [0167] connected to the patient-side coupling unit 43 [0168] W Wall; it has the supply ports 60 and 61