COATED ANESTHETIC CONTAINER FOR AN ANESTHETIC DISPENSER AND MANUFACTURING PROCESS

Abstract

A coated anesthetic container for an anesthetic dispenser includes an anesthetic tank, which is capable of receiving a liquid anesthetic (Nm), as well as a refill unit for refilling liquid anesthetic (Nm). The anesthetic tank includes a wall and a coating on the inner surface of the wall. A wall of the refill unit is connected in a fluid-tight manner to the wall of the anesthetic tank. A coating is applied at least to the inner surface of the wall of the anesthetic tank. This coating is made of an alloy of nickel and phosphorus. The nickel portion is in a range of 80 wt.% to 97 wt.%, and the phosphorus portion is in a range of 3 wt.% to 15 wt.%. A process is provided for manufacturing such an anesthetic container.

Claims

1. An anesthetic container for use in an anesthetic dispenser, the anesthetic container comprising: an anesthetic tank for receiving a liquid anesthetic, the anesthetic tank comprising a wall with an inner surface and a coating on the inner surface, the inner surface pointing toward a liquid anesthetic in the anesthetic tank; and a refill unit for refilling liquid anesthetic into the anesthetic tank, wherein the coating of the anesthetic tank comprises an alloy with a nickel portion in a range of 80 weight % to 97 weight %, and a phosphorus portion in a range of 3 weight % to 15 weight %.

2. An anesthetic container in accordance with claim 1, wherein the range of the phosphorus portion is 10 weight % to 13 weight %.

3. An anesthetic container in accordance with claim 1, further comprising a visual inspection unit configured to provide a visible fill level of liquid anesthetic in the anesthetic tank from outside the anesthetic tank through the visual inspection unit.

4. An anesthetic container in accordance with claim 3, wherein the visual inspection unit comprises a transparent material including a quartz portion of at least 70 weight %, preferably a quartz portion of at least 80 weight %.

5. An anesthetic container in accordance with claim 3, further comprising a transparent coating comprising a plastic applied to an inner surface of the visual inspection unit.

6. The anesthetic container in accordance with claim 5, wherein the plastic of the transparent coating comprises: a parylene; or a polymer; or a transparent polytetrafluoroethylene; or a polyolefin; or any combination of a parylene, and a polymer, and a transparent polytetrafluoroethylene, and a polyolefin.

7. An anesthetic container in accordance with claim 1, wherein the wall of the anesthetic tank comprises at least one metal alloy with an aluminum portion of at least 80 weight %.

8. An anesthetic container in accordance claim 1, wherein the wall of the anesthetic tank comprises plastic, the plastic comprising at least one of: a polyamide; or a polyphenylene sulfide; or a polyether ether ketone.

9. An anesthetic container in accordance with claim 1, wherein the refill unit comprises: a refill unit wall; and a coating on an inner surface of the refill unit wall, wherein the refill unit wall is connected in a fluid-tight manner to the wall of the anesthetic tank, and wherein a refill unit wall coating of the wall of the refill unit comprises a same material as or is made of the same material than the coating of the anesthetic tank.

10. An anesthetic container in accordance with claim 3, wherein the visual inspection unit comprises a transparent material including a quartz portion of at least 80 weight %.

11. An anesthetic container in accordance with claim 3, wherein the visual inspection unit comprises a transparent material including a quartz portion of at least 90 weight %.

12. An anesthetic container in accordance with claim 3, wherein the visual inspection unit comprises a transparent material including a quartz portion of at least 99 weight %.

13. An anesthetic container in accordance with claim 1, wherein the wall of the anesthetic tank comprises at least one metal alloy with an aluminum portion of at least 95 weight %.

14. An anesthetic dispenser comprising: an anesthetic container comprising: an anesthetic tank for receiving a liquid anesthetic, the anesthetic tank comprising a wall with an inner surface and a coating on the inner surface, the inner surface pointing toward a liquid anesthetic in the anesthetic; and a refill unit for refilling liquid anesthetic into the anesthetic tank, wherein the coating of the anesthetic tank comprises an alloy with a nickel portion in a range of 80 weight % to 97 weight %, and a phosphorus portion in a range of 3 weight % to 15 weight %; a feed device configured to be in a fluid connection with the anesthetic container; and an anesthetic vaporizer, wherein the feed device is configured to feed liquid anesthetic from the anesthetic container into the anesthetic vaporizer, and wherein the anesthetic vaporizer is configured to generate gaseous anesthetic with the use of the liquid anesthetic fed in by the feed unit.

15. An anesthetic dispenser in accordance with claim 14, in combination with a gas mixer to form a gas mixture generator, wherein the gas mixer is configured to be in a fluid connection with the anesthetic dispenser, wherein the gas mixer is configured to generate a gas mixture comprising oxygen and at least one gaseous anesthetic, wherein the gaseous anesthetic is generated by the anesthetic dispenser.

16. An anesthetic dispenser in combination with a gas mixer to form a gas mixture generator according to claim 15, in combination with a fluid delivery unit to form a ventilation system for the mechanical ventilation of a patient, wherein the patient is connected or connectable to a patient-side coupling unit, wherein a fluid connection is established or establishable between the ventilation system and the patient-side coupling unit, wherein the fluid delivery unit is configured to deliver the gas mixture through the fluid connection to the patient-side coupling unit.

17. A process for manufacturing an anesthetic container, the anesthetic container comprising: an anesthetic tank for receiving a liquid anesthetic, the anesthetic tank comprising a wall with an inner surface and a coating on the inner surface, the inner surface pointing toward a liquid anesthetic in the anesthetic tank; and a refill unit for refilling liquid anesthetic into the anesthetic tank, wherein the coating of the anesthetic tank comprises an alloy with a nickel portion in a range of 80 weight % to 97 weight %, and a phosphorus portion in a range of 3 weight % to 15 weight %, wherein a lower threshold is predefined for a layer thickness of the coating on the inner surface of the anesthetic tank and a pH value is predefined as a function of the predefined range for the phosphorus portion in the coating on the inner surface, and wherein the process comprises the steps of: manufacturing the wall of the anesthetic tank; providing a dipping bath with a liquid containing nickel and phosphorus, wherein the liquid has the predefined pH value, moving the wall in to a dipping bath; wherein the liquid in the dipping bath encloses the wall after the movement; and leaving the wall in the dipping bath, so that a coating is formed on both sides of the wall and leaving the wall in the dipping bath until at least the coating on the inner surface of the wall reaches a wall thickness that is greater than or equal to the predefined lower threshold for the layer thickness.

18. A process in accordance with claim 17, wherein an electroless nickel plating process is used during the step of leaving the wall in the dipping bath, so that the two coatings are formed.

19. A process in accordance with claim 17 wherein: the refill unit comprises: a refill unit wall; and a coating on an inner surface of the refill unit wall, wherein a refill unit wall coating of the wall of the refill unit comprises a same material as or is made of the same material than the coating of the anesthetic tank; and a part comprising the wall of the anesthetic tank and the wall of the refill unit is manufactured such that the two walls are connected to one another in a fluid-tight manner, the part is moved into the dipping bath, and the part is left in the dipping bath until at least the coating on the inner surface of the two walls has reached a wall thickness that is greater than or equal to the predefined lower threshold for the layer thickness.

20. A process for manufacturing an anesthetic container comprising the process steps of: providing an anesthetic container comprising an anesthetic tank for receiving a liquid anesthetic, the anesthetic tank comprising a wall with an inner surface and a coating on the inner surface pointing toward a liquid anesthetic space; and a refill unit for refilling liquid anesthetic into the anesthetic tank, wherein the coating of the anesthetic tank comprises an alloy with a nickel content in a range of 80 weight % to 97 weight %, and a phosphorus content in a range of 3 weight % to 15 weight %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the drawings:

[0048] FIG. 1 is a schematic view showing a system for the mechanical ventilation of a patient;

[0049] FIG. 2 is a schematic view showing a single anesthetic dispenser;

[0050] FIG. 3 is a schematic view showing an anesthetic tank in a cross-sectional view; and

[0051] FIG. 4 is a schematic view showing a front view of the anesthetic tank from FIG. 3 with an inspection tube.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0052] FIG. 1 schematically shows a system 200 for the mechanical ventilation of a patient Pt. The patient Pt is connected to a patient-side coupling unit 2, for example, to a breathing mask on the face or to a tube or to a catheter in the body of the patient Pt.

[0053] The ventilation system 200 carries out a sequence of ventilation strokes. During each ventilation stroke a ventilation gas mixture comprising oxygen and at least one anesthetic is delivered through a fluid connection 130 to the patient-side coupling unit 2. Because of the anesthetic in the gas mixture being fed, the patient Pt is sedated or even anesthetized. The air exhaled by the patient Pt is sent back to the ventilation system again, so that no anesthetic is released into the surrounding area. As a result, a ventilation circuit is established between the ventilation system 200 and the patient-side coupling unit 2. A fluid delivery unit in the form of a pump 120 maintains a gas flow in this ventilation circuit.

[0054] The ventilation system 200 comprises an anesthesia device 1, which carries out the ventilation strokes, and two gas mixture generators 100.1 and 100.2. The two gas mixture generators 100.1, 100.2 are connected to the anesthesia device 1 in a detachable manner. The pump 120 belongs to the anesthesia device 1. Each gas mixture generator 100.1, 100.2 is supplied with a carrier gas comprising oxygen from the anesthesia device 1 and generates an anesthetization gas mixture comprising the carrier gas and at least one anesthetic. The anesthesia device 1 generates the ventilation gas mixture with the use of the anesthetization gas mixture and delivers the ventilation gas mixture to the patient-side coupling unit 2. The oxygen portion content in the ventilation gas mixture may be the same as the oxygen portion in breathing air. It is possible that the anesthetization gas mixture is used as the ventilation gas mixture. The anesthesia device 1 optionally increases the oxygen portion in the ventilation gas mixture.

[0055] A gas mixture generator 100.1 or 100.2 is usually used to sedate or to anesthetize a patient Pt. The other gas mixture generator 100.2 or 100.1 is likewise connected to the anesthesia device 1 and is currently not used, but is available to be used immediately as needed. As a rule, it is possible to switch over rapidly from the one gas mixture generator 100.1 to the other gas mixture generator 100.2, without interrupting the anesthetization of the patient Pt.

[0056] FIG. 1 further shows a supply port 20 for the carrier gas and a supply port 21 for compressed air, wherein both supply ports 20, 21 are arranged in a wall W and belong to a stationary supply system. In the ventilation circuit, excess gas is generated, which is sent to a disposal port 22 in the wall W and is received there.

[0057] FIG. 2 schematically shows a single gas mixture generator 100. This gas mixture generator comprises an anesthetic dispenser 80 and a gas mixer 60. The carrier gas is fed to the gas mixer 60 via an inlet 17. The anesthetic dispenser 80 generates gaseous anesthetic, which is likewise fed to the gas mixer 60. The gas mixer 60 generates the anesthetization gas mixture from the gaseous anesthetic and the carrier gas. The anesthetization gas mixture generated is then discharged via an outlet 19 and delivered to the patient-side coupling unit 2, cf. FIG. 1.

[0058] Liquid anesthetic Nm is stored in an anesthetic tank 5 of an anesthetic container 8 of the anesthetic dispenser 80. It is possible that the anesthetic dispenser 80 comprises an additional anesthetic tank (not shown), wherein this additional anesthetic tank is in a fluid connection with the anesthetic tank 5 and hence does not necessarily comprise a closable refill unit of its own. This fluid connection acts as the refill unit of the additional anesthetic tank.

[0059] An inspection glass 30 is inserted into a wall of the anesthetic tank 5. A user or even a camera can visually determine from outside through the inspection glass 30 the current fill level of the liquid anesthetic in the anesthetic tank 5. A protective layer, which protects the inspection glass 30 from mechanical damage from outside, is located outside on the inspection glass 30 in one embodiment. A fill level sensor 4 measures a value indicative of the current fill level of the liquid anesthetic Nm in the anesthetic tank 5.

[0060] Liquid anesthetic Nm can be refilled through a closable neck 7. The neck 7 acts as the refill unit of the anesthetic tank 5 and comprises an adapter, onto which a container can be placed in a fluid-tight manner for refilling liquid anesthetic. A cylinder 32 containing liquid anesthetic is shown as an example as a refill container for refilling. The cylinder 32 can be placed onto an adapter at the neck 7 such that a fluid-tight connection is established and the liquid anesthetic can flow from the cylinder 32 through the neck 7 downwards into the anesthetic tank 5. The neck 7 is fastened to a side wall of the anesthetic tank 5 in the embodiment being shown. It may also be arranged in the cover 10 of the anesthetic tank 5.

[0061] A gas mixture comprising anesthetic is present in the anesthetic tank 5 above the level of the liquid anesthetic. The boiling point of some frequently used anesthetics is below 40° C. Hence, an overpressure compared to the ambient pressure especially develops in the interior of the anesthetic container 8. In the exemplary embodiment, the anesthetic container 8 is configured such that it can withstand an overpressure up to a structure-related overpressure threshold. This overpressure threshold is in a range of 1 bar to 50 bar, and preferably in a range of 1 bar to 20 bar.

[0062] A pressure sensor 3 measures a value indicative of the pressure of this gas mixture. The anesthetic tank 5 is connected to a port 59 via a line. The pressure in the anesthetic tank 5 can be altered by means of a proportional valve 66. A signal-processing control device, not shown, preferably receives measured values from the pressure sensor 3 and actuates the proportional valve 66 as a function of the measured pressure in the anesthetic tank 5. The control device actuates the proportional valve 66 with the control target that the actual pressure in the anesthetic tank 5 follows a predefined pressure time curve.

[0063] Liquid anesthetic Nm flows through a vaporizer feed line 40 to a vaporizer chamber 13 of an anesthetic vaporizer 50. An actuatable proportional valve 11 as well as a feed device in the form of an actuatable injection valve 12 are arranged in this line 40. The control device actuates the proportional valve 11 and as a result controls the volume flow of liquid anesthetic Nm through the line 40. The injection valve 12 injects liquid anesthetic Nm into the vaporizer chamber 13 of the anesthetic vaporizer 50. An actuatable heater 16 contributes to vaporizing the liquid anesthetic Nm in the vaporizer chamber 13. A temperature sensor 14 measures a value indicative of the temperature in the vaporizer chamber 13.

[0064] The gaseous anesthetic flows from the vaporizer chamber 13 through a mixer feed line 41 with a pneumatic resistance 15, which is preferably actuatable, into a mixing chamber 18 of the gas mixer 60. The gaseous anesthetic is mixed together with a carrier gas in this mixing chamber 18. An actuatable heater 69 is capable of heating the gas mixture in the mixing chamber 18. A temperature sensor 70 measures a value indicative of the temperature in the mixing chamber 18.

[0065] In addition, a plurality of filters 49 are shown in FIG. 2.

[0066] FIG. 3 schematically shows a cross section through the anesthetic container 8, wherein the anesthetic container 8 comprises the anesthetic tank 5, the neck 7, the closure 23 and the inspection glass 30. The geometry of the anesthetic container 8 is shown in a simplified manner. A tub of the anesthetic tank 5 is closed in a fluid-tight manner by a cover 10. During the regular operation, this cover 10 remains on the tub of the anesthetic tank 5. The cover may be opened, e.g., for the purpose of maintenance. The tub and the cover 10 are intended by “the anesthetic tank” below. The neck 7 is closed by a closure 23 in a fluid-tight manner. The closure 23 can be removed from the neck 7, especially in order to refill liquid anesthetic Nm into the anesthetic tank 5, without having to remove the cover 10.

[0067] The anesthetic tank 5 comprises a wall 24. This wall 24 is formed by the tub and by the cover 10 in the embodiment being shown. The neck 7 comprises a wall 26. The respective wall thickness of the wall 24, 26 is set such that the anesthetic container 8 can withstand an overpressure in its interior up to the above-mentioned overpressure threshold. The wall thickness is preferably in a range of 4 mm to 30 mm.

[0068] In one embodiment, the wall 24, 26 of the anesthetic container 8 is manufactured as one part. In another embodiment, two halves of the wall 24, 26 are manufactured separately from one another. These two halves are subsequently connected to one another by laser welding or by another joining technique. A process for manufacturing the wall 24, 26 of the anesthetic container 8 in such a manner is described in DE 10 2004 041 448 B3 and US 7,648,039 B2.

[0069] Different processes are possible for how the wall 24, 26 or even the two halves are manufactured. It is possible to manufacture the wall 24, 26 from a liquid material by means of a casting process, and preferably by means of die-casting. It is also possible to manufacture the wall 24, 26 from at least one metal sheet using an extrusion process. If an extrusion or casting process is used, then the wall thickness is preferably in a range of 4 mm to 23 mm. In another embodiment, the wall 24, 26 is manufactured by milling. The wall thickness may then be above 23 mm.

[0070] At least two of these processes can also be combined with one another. For example, some parts, for example, connection pieces between the neck 7 and the anesthetic tank 5, are manufactured by milling and the remaining parts are manufactured by die-casting or extrusion. The milled parts are subsequently connected to the remaining parts by means of laser welding or by means of another joined connection. It is possible that the parts of the wall 24, 26, which are manufactured using extrusion or casting, have a lower wall thickness than the parts that are manufactured by milling.

[0071] The walls 24 and 26 are preferably manufactured from the same material. It is possible that one material is used for die-casting or for extrusion and a different material is used for milling.

[0072] Different materials for the wall 24, 26 are possible. In a preferred embodiment, the material is a metal alloy, which has an aluminum (Al) portion of at least 80%, preferably of at least 90%, and especially preferably of 95%. Because the aluminum portion is at least 80%, the wall 24, 26 has a relatively low weight and can be molded into a desired shape relatively easily. Aluminum has, in addition, a sufficiently high corrosion resistance.

[0073] An aluminum alloy according to EN AW-6063 is especially preferably used as the material for the extrusion or die-casting. This material for the wall 24 has a magnesium (Mg) portion in a range of 0.45 wt.% to 0.9 wt.%, a silicon (Si) portion in a range of 0.2 wt.% to 0.6 wt.%, an iron (Fe) portion of 0.35 wt.% as well as additional elements with lower contents. An aluminum alloy according to EN AW-5083 is especially preferably used for the milling. The magnesium (Mg) portion is in a range of 4 wt.% to 4.9 wt.%, the manganese (Mn) portion is in a range of 0.4 wt.% to 1 wt.%, and the silicon (Si) portion and the iron (Fe) portion are each 0.4 wt.%.

[0074] The metal alloy may also have a magnesium (Mg) portion of at least 80 wt.%, and preferably of at least 90 wt.%. This alloy preferably contains an aluminum portion, which is in a range of 6 wt.% to 12 wt.%, as well as a zinc portion and a manganese portion, which are each below 1 wt.%. The metal alloy may also have a brass portion of at least 80 wt.%, preferably of at least 90 wt.%. As is known, brass is an alloy containing at least 50 wt.% copper (Cu) and at most 40 wt.% zinc (Zn).

[0075] It is also possible to use a plastic instead of a metal alloy. When the wall 24, 26 is manufactured from plastic and not from a metal alloy, then it is not magnetic and also cannot be magnetized. In addition, it is then not able to corrode and has in many cases a lower weight than a wall 24, 26 made of a metal alloy. A wall 24, 26 made of plastic is preferably manufactured by means of a casting process, and especially preferably by means of die-casting. At least one of the following plastics is preferably used: [0076] a polyamide, [0077] a polyphenylene sulfide (PPS) or [0078] a polyether ether ketone (PEEK, also called PEAK).

[0079] It is desired that the wall 24, 26 be continuously made of a homogeneous material. However, in practice, pores may develop in the wall 24, 26. The wall 24, 26 is preferably manufactured such that the maximum diameter of a pore is at most 30 .Math.m.

[0080] In one embodiment, the closure 23 is manufactured from a flexible plastic. As a result, the closure 23 fills out the entire cross-sectional area of the neck 7, on the one hand, and, on the other hand, can be compressed to pull the closure 23 from the neck 7, or it is compressed when the closure 23 is pulled from the neck 7. The material, from which the closure 23 is manufactured, preferably comprises a polyphenylene sulfide (PPS), especially preferably a polyphenylene sulfide reinforced with glass fiber. The closure 23 may also comprise a rigid part with an external thread, wherein the external thread meshes with an internal thread of the neck 7. The rigid closure 23 preferably comprises, furthermore, a seal.

[0081] The anesthetic tank 5 is capable of receiving a liquid anesthetic. The same anesthetic tank 5 is able to receive different anesthetics one after the other. During refilling, liquid anesthetic Nm flows through the neck 7 into the anesthetic tank 5. What requirements result from the anesthetic tank 5 receiving a liquid anesthetic and how these requirements are met according to the present invention will be explained below.

[0082] A frequently used anesthetic has become known by the name sevoflurane. Sevoflurane has the chemical empirical formula (CF3).sub.2CHOCHF.sub.2 and the chemical name 1,1,1,3,3,3-hexafluoro-2-fluoromethoxy propane. Other frequently used anesthetics have the names isoflurane and desflurane.

[0083] It is known that liquid anesthetics, for example, the anesthetics just mentioned, are chemically aggressive. Hence, only materials with a sufficient chemical resistance to liquid anesthetics may be considered to be materials that come into contact with liquid anesthetics. The inventors have, in addition, found in internal experiments that a wall 24, 26 with a high aluminum portion can easily be manufactured, but has an undesirable action on a liquid anesthetic Nm in the anesthetic tank 5 under unfavorable conditions, especially when one of the anesthetics just mentioned is used. In particular, the metal alloy of the wall 24 may chemically alter the anesthetic Nm in the anesthetic tank 5 or reduce the anesthetizing action thereof or even decompose the anesthetic Nm. A chemical action of the wall alloy on the liquid anesthetic Nm may lead to so-called Lewis acids being formed. The formation of these Lewis acids may lead to harmful substances, and especially hydrofluoric acid (HF), being formed. The risk of this undesirable action occurs especially when the liquid anesthetic Nm remains in the anesthetic tank 5 for a relatively long time or when the anesthetic container 8 is exposed to a relatively high ambient temperature of above 35° C.

[0084] A coating 25, which is arranged between the wall 24 and the liquid anesthetic Nm in the anesthetic tank 5, is applied to the inside of the wall 24 of the anesthetic tank 5, including of the cover 10. The coating 25 covers the entire inside of the wall 24 and largely prevents the liquid anesthetic Nm from coming into contact with the wall 24. In the exemplary embodiment, a coating 27 that covers the entire inside of the wall 26 is applied to the inside of the wall 26 of the neck 7. The coating 25, 27 preferably forms a continuous coating for the entire inner wall of the anesthetic container 8. Two possible exceptions: The inner surface of the closure 23 and the inner surface of the inspection glass 30 are free from this coating 25, 27.

[0085] It is also possible that only the inner surface of the anesthetic tank 5 is provided with the coating 25 according to the present invention and the inner surface of the neck 7 is not coated at all or has a different coating. Especially when the neck 7 is arranged in or close to the cover 10, the neck 7 comes into contact with a liquid anesthetic Nm for a shorter time, for example, during the refilling, than the tub of the anesthetic tank 5.

[0086] The coating 25, 27 ideally completely prevents a liquid anesthetic in the anesthetic container 8 from coming into contact with the wall 24, 26. In practice, the coating 25, 27 does not cover the wall 24, 26 completely and in a gap-free manner, so that a contact occurs between the wall 24, 26 and the liquid anesthetic Nm in spite of the coating 25, 27. One possible cause are pores in the wall 24, 26, the maximum diameter of which is greater than the layer thickness of the coating 25, 27. In many cases, however, it is possible to achieve that the size of this remaining contact surface is at most 5%, in some cases even at most 1%, of the entire area of the wall 24, 26.

[0087] The layer thickness of the coating 25, 27 is in a range of 0.5 .Math.m to 80 .Math.m, preferably in a range of 10 .Math.m to 20 .Math.m. The coating 25, 27 especially preferably has a uniform layer thickness of 15 .Math.m ± 2 .Math.m.

[0088] An alloy comprising nickel (Ni) and phosphorus (P) and optionally additional components is used as the material for the coating 25, 27 according to the present invention. This alloy is sufficiently chemically resistant to a liquid anesthetic in the anesthetic container 8 and does not exert an undesirable action on the liquid anesthetic Nm. The phosphorus content in this alloy is at least 3 wt.% and at most 15 wt.%. The phosphorus portion is preferably at least 10 wt.% and at most 13 wt.%. Such a coating is also called nickel phosphorus (NP) or even “chemical nickel.” Thanks to the phosphorus portion, the coating 25, 27 is relatively resistant to wear and corrosion.

[0089] In case the phosphorus portion is above 10 wt.%, the coating has, moreover, a fully amorphous structure. Therefore, the risk that inhomogeneities such as grain boundaries or separated phases will develop in the coating 25 is relatively low. Furthermore, the risk that crystals, which may lead to an uneven surface of the coating 25, will be formed during the manufacture of the coating 25, 27 is low.

[0090] Different alternatives for manufacturing an anesthetic container 8 according to the present invention will be described below. In all these alternatives, first a part is manufactured, which comprises the two walls 24, 26 and the optional inspection window 30, but no coating according to the present invention on the inner surface.

[0091] It is possible to spray the coating 25, 27 onto the inner wall of the provided part 24, 26, 30. It is also conceivable to fill a suitable liquid into the interior of the provided part 24, 26, 30, to leave this liquid there until the coating 25, 27 has formed, and then pouring out the liquid again.

[0092] In a preferred embodiment, the coating 25, 27 is, by contrast, generated in a dipping bath with a liquid comprising nickel and phosphorus. The part having the wall 24, 26 and having the optional inspection window 30 is lowered into this dipping batch, especially preferably such that the part 24, 26, 30 is completely submerged in the liquid. The coating 25, 27 is formed on the wall 24, 26 by a chemical or electrochemical reaction.

[0093] If a dipping bath is used, then not only is the inside of the wall 24, 26 coated, but also the outside. Possible holes, bulges, undercuts as well as optional lines are likewise coated in the dipping bath. This coating on the outside increases the chemical and mechanical resistance of the wall 24, 26 in many cases.

[0094] The coating process by means of a dipping bath leads to the layer thickness of the coating 25, 27 being relatively consistent over the entire extension of the wall 24, 26. It is possible in many cases to achieve that the thickness of the coating 25, 27 varies spatially by at most ± 5 .Math.m or even only by ± 3 .Math.m. Often, it is possible to achieve that unevennesses in the inner surface of the wall 24, 26 of the anesthetic container 8 are compensated for by the coating 25, 27 and even at least some of the pores are closed.

[0095] The coating 25, 27 is preferably applied to the part 24, 26, 30 in a dipping bath by means of a redox reaction or by means of a galvanic process with an electrolyte or by anodization. The part 24, 26, 30 is lowered into the dipping bath. The dipping bath comprises, for example, a tub and provides a liquid that contains nickel and phosphorus. During the redox reaction, which is also known by the name electronic nickel or “chemical nickel,” nickel ions are deposited on the inner surface of the wall 24, 26 by means of a chemical oxidation reaction.

[0096] The redox reaction generates the necessary electrons proper. Hence, it is not necessary to apply an electrical voltage. In some cases, it is therefore possible to apply the coating 25, 27 to the wall 24, 26 by means of a chemical reaction in a dipping bath even if the wall 24, 26 is manufactured from a plastic or from another material, which is not electrically conductive, and therefore, a galvanic process is not possible. In addition, no supply with electric energy is needed in some cases.

[0097] Two chemical partial reactions, namely [0098] (1) 3 NaH.sub.2PO.sub.2 + 3 H.sub.2O + NiSO.sub.4 ➨ 3 NaH.sub.2PO.sub.3 + H.sub.2SO.sub.4 + 2 H.sub.2 + Ni and [0099] (2) NaH.sub.2PO.sub.2 + H.sub.nas ➨ H.sub.2O + NaOH + P take place during the coating in one embodiment.

[0100] The lower the pH value of the electrolyte is in the dipping bath, the slower the partial reaction (1) proceeds and the faster the partial reaction (2) proceeds. The phosphorus portion in the coating 25, 27 can be set by means of a suitable selection of the pH value of the liquid in the dipping bath. A pH value of the liquid provided in the dipping bath is therefore derived and predefined as a function of a desired phosphorus portion in the coating 25, 27 to be manufactured. The residence time of the part with the two walls 24, 26 in the dipping bath determines the obtained layer thickness of the coating 25, 27.

[0101] The coating 25, 27 is especially preferably manufactured according to DIN EN ISO 4527. The alloy comprising nickel and phosphorus with a phosphorus portion of preferably at least 10 wt.% leads to a supersaturated solution of phosphorus in the nickel.

[0102] Some process steps, which belong to the manufacturing process, by means of which the anesthetic tank 8 is manufactured, will be explained below as examples. [0103] A part, which comprises the wall 24, 26 and the optional inspection window 30, is first manufactured. [0104] Lubricants and optionally welding burrs are removed from this part 24, 26. [0105] An oxide layer is removed at least once from the two surfaces of the wall 24, 26. [0106] In addition, the part 24, 26, 30 is rinsed at least once. [0107] The two surfaces of the wall 24, 26 are pretreated so that the coating 25, 27 according to the present invention adheres better. [0108] The part with the wall 24, 26 is inserted into a dipping bath, which contains a mixture comprising nickel and phosphorus in the liquid form and has a predefined pH value. An expanding coating 25, 27 is formed in the dipping bath on the two surfaces of the wall 24, 26. The part 24, 26, 30 is left in the dipping bath until the layer thickness of the coating 25, 27 has reached a predefined lower threshold for the layer thickness. For example, it is empirically determined beforehand at what rate the layer thickness of the coating 25, 27 increases in the dipping bath, and a residence time of the part 24, 26 in the dipping bath is derived from the empirically determined rate of increase and from the predefined lower threshold.

[0109] At least some of the steps, removing lubricants as well as an oxide layer, rinsing the part and pretreating the surfaces, can also be carried out in a respective dipping bath.

[0110] A user may visually determine the fill level of the liquid anesthetic Nm in the anesthetic tank 5 from outside. Hence, in the embodiment according to FIG. 3, a transparent inspection glass 30 is inserted into the wall 24 of the anesthetic tank 5. An O ring preferably encloses the inspection glass 30 and seals the gap between the inspection glass 30 and the wall 24. This O ring is manufactured from an elastic material, which is sufficiently chemically resistant to anesthetics. An elastomer, especially preferably the material ethylene propylene diene rubber (EPDM), is preferably used as a material for the O ring.

[0111] FIG. 4 shows in a front view an alternative embodiment. In the view according to FIG. 4, the neck 7 points toward the viewer. A vertical inspection tube 31 is inserted in a fluid-tight manner into the wall 24 of the anesthetic tank 5. In the example shown, the wall 24 forms an indentation 33 and the inspection tube 31 is enclosed by the indentation 33 such that the inspection tube 33 does not protrude over the wall 24 on the outside. The inspection tube 31 is in a respective fluid connection with the interior of the anesthetic tank 5 both at the top and at the bottom, so that the fill level of the liquid anesthetic Nm in the anesthetic tank 5 is consistent with the fill level in the inspection tube 31 according to the principle of communicating tubes. For example, liquid anesthetic enters into the inspection tube 31 from the bottom during the refilling, and gas may leak out of the inspection tube 31 upwards.

[0112] The generic term “visual inspection unit” is used below for the inspection glass 30 from FIG. 3 and the inspection tube 31 from FIG. 4.

[0113] In a preferred embodiment, the visual inspection unit 30, 31 is manufactured from a material that has a quartz (silicon dioxide, SiO.sub.2) portion of at least 85 wt.%, preferably a quartz portion of at least 95 wt.%, and especially preferably a quartz portion of at least 99 wt.%.

[0114] In addition, the material contains metals, preferably especially aluminum (Al). A material with a quartz portion of at least 85 wt.% is in many cases sufficiently chemically resistant to anesthetics, so that a coating on the inside of the inspection glass 30 is possible, but frequently not necessary.

[0115] In an alternative embodiment, the visual inspection unit 30, 31 is manufactured from a material that does not necessarily have a quartz portion of at least 85 wt.%. For example, a borosilicate glass is used as material. Borosilicate glass comprises 70 wt.% to 80 wt.% silicon dioxide (SiO.sub.2), 7 wt.% to 13 wt.% boron trioxide (B.sub.2O.sub.3), 4 wt.% to 8 wt.% alkali oxides, for example, sodium oxide (Na.sub.2O) or potassium oxide (K.sub.2O), as well as optionally additional components.

[0116] A transparent coating consisting of a plastic is applied to the inner surface of the visual inspection unit 30, 31 especially in case of a quartz portion below 85 wt.%. This transparent coating on the inner surface prevents an undesirable interaction between the visual inspection unit 30, 31 and the liquid anesthetic Nm in the anesthetic tank 5. The transparent plastic preferably comprises at least one of the following substances: [0117] a Parylene, [0118] a polymer, preferably an epoxy phenolic polymer, [0119] a transparent polytetrafluoroethylene (PTFE), [0120] a polyolefin.

[0121] 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.

TABLE-US-00001 List of Reference Characters 1 Anesthesia device; it belongs to the ventilation system 200; it comprises the fluid delivery unit 120 2 Patient-side coupling unit; it is connected to the patient Pt 3 Pressure sensor; it measures a value indicative of the pressure in the anesthetic tank 5 4 Fill level sensor; it measures a value indicative of the fill level of the liquid anesthetic Nm in the anesthetic tank 5 5 Anesthetic tank; it contains the liquid anesthetic Nm; it comprises the wall 24 and the coating 25 7 Closable neck for refilling liquid anesthetic Nm into the anesthetic tank 5 8 Anesthetic container; it comprises the anesthetic tank 5 and the neck 7 10 Cover on the tub of the anesthetic tank 5; it belongs to the wall 24 11 Proportional valve in the line 40 12 Actuatable injection valve for liquid anesthetic; it acts as a feed device 13 Vaporizer chamber, in which liquid anesthetic Nm is vaporized or evaporated; it belongs to the anesthetic vaporizer 50 14 Temperature sensor; it measures a value indicative of the temperature in the vaporizer chamber 13; it belongs to the anesthetic vaporizer 50 15 Pneumatic resistance in the line 41; it can be optionally actuated 16 Anesthetic heater of the anesthetic vaporizer 50; it heats the vaporizer chamber 13; it belongs to the anesthetic vaporizer 50 17 Inlet, via which the carrier gas is fed to the gas mixture generator 100 18 Mixing chamber, in which the gaseous anesthetic is mixed with the carrier gas; it belongs to the gas mixer 60 19 Outlet, via which the anesthetization gas mixture comprising carrier gas and anesthetic is discharged from the gas mixture generator 100 20 Supply port in the wall W for carrier gas 21 Supply port in the wall W for compressed air 22 Disposal port in the wall W for receiving excess gas mixture from the ventilation system 200 23 Removable closure for the neck 7 24 Wall of the anesthetic tank 5; it is provided with the coating 25 on the inner surface 25 Coating on the inner wall of the wall 24 of the anesthetic tank 5, consisting of nickel with at least 3 wt.% and at most 15 wt.% phosphorus 26 Wall of the neck 7; it is provided with the coating 27 on the inside 27 Coating on the inner wall of the neck 7 30 Inspection glass for visually determining the fill level in the anesthetic tank 5; it is inserted into the wall 24 in a fluid-tight manner; it is manufactured from quartz glass or borosilicate glass; it optionally comprises an inner coating 31 Inspection tube for visually determining the fill level in the anesthetic tank 5; it is arranged in the indentation 33; it is connected to the wall 24 in a fluid-tight manner 32 Refill container for liquid anesthetic Nm; it can be placed on the neck 7 33 Indentation in the wall 24; it accommodates the inspection tube 31 40 Vaporizer feed line; it leads from the anesthetic tank 5 to the vaporizer chamber 13 41 Mixer feed line; it leads from the vaporizer chamber 13 to the mixing tank 18 49 Filter 50 Anesthetic vaporizer; it comprises the vaporizer chamber 13, the anesthetic heater 16 and the temperature sensor 14; it belongs to the anesthetic dispenser 50 59 Port of the anesthetic dispenser 100, via which the pressure in the anesthetic tank 5 is controlled 60 Gas mixer; it comprises the mixing chamber 18, the mixing chamber heater 69 and the temperature sensor 70; it generates an anesthetization gas mixture comprising a carrier gas and gaseous anesthetic; it belongs to the gas mixture generator 100 66 Proportional valve, with which the pressure in the anesthetic tank 5 is controlled 69 Mixing chamber heater; it is capable of heating the gas mixture in the mixing chamber 18; it belongs to the gas mixer 60 70 Temperature sensor; it measures a value indicative of the temperature in the mixing chamber 18; it belongs to the gas mixer 60 80 Anesthetic dispenser; it comprises the anesthetic container 8, the anesthetic vaporizer 50 and the vaporizer feed line 40; it belongs to the gas mixture generator 100 100, 100.1, 100.2 Gas mixture generator; it comprises the anesthetic dispenser 80 and the gas mixer 60 120 Fluid delivery unit in the form of a pump; it maintains a stream of gas in the ventilation circuit 130 Fluid connection between the ventilation system 200 and the patient-side coupling unit 2 200 System for the mechanical ventilation of the patient Pt; it comprises the anesthesia device 1, the pump 120 and the anesthetic dispensers 100.1, 100.2 Nm Liquid anesthetic in the anesthetic tank 5 Pt Patient; he is mechanically ventilated; he is connected to the patient-side coupling unit 2 W Wall; it carries the supply ports 20 and 21 and the port 59