DE102005042182B4 - Apparatus for ventilation - Google Patents

Abstract

Device for ventilation, which is designed as a ventilator and has at least one flow path and which consists of a plurality of interconnected components, which are arranged along the flow path one behind the other and through which the flow path passes, characterized in that the flow resistance of each individual component (1) is optimized for achieving a low resulting total flow resistance of all components (1), wherein the flow path (12) is provided with flow guide elements (18) in the region of at least one change in cross section and the change in cross section is formed as a stepped extension (20) having a first cross sectional area (14 ) into a second cross-sectional area (15), wherein the flow guide elements (18) extends from an edge (21) of the first cross-sectional area (14) into the flow area of the second cross-sectional area (15) and wherein the flow gsleitelemente (18) are formed as brush edges or as soft fins or of an open-pore material.

Description

The invention relates to a device for ventilation, which is designed as a respirator and which has at least one flow path and which consists of a plurality of interconnected components, which are arranged along the flow path one behind the other and through which the flow path passes.

In known ventilators, the airway is characterized by a plurality of components having different functions. In particular, these are air inlet filters, air lines in the ventilator, silencer, fan, air line to the patient, hose, patient interface (mask, tube, nasalpillow).

From the DE 100 51 891 A1 already a device for ventilation is known which has at least one flow path.

Likewise is from the DE 10 2005 031 541 A1 a device for ventilation, which has at least one flow path.

The WO 99/24749 A1 also describes a ventilation device having at least one flow path.

Another device for ventilation, which has at least one flow path, is from the US 4,967,744 known.

The DE 10 2004 025 674 A1 describes a ventilator for performing CPAP ventilation.

A further prior art is from the DE 10 2004 025 671 known.

The invention can be used, for example, in the following medical devices: CPAP, APAP, bilevel, titration, home ventilation, emergency, hospital ventilation, suction and other medical devices.

In the known devices, the individual elements of the airway are each optimized for their function, but not in the sense of optimal flow guidance. For example, the muffler should primarily minimize the sound, but not allow an ideal flow of the breathing gas. In interaction, however, there are particularly flow effects that increase the sound and energy consumption and worsen the quality of the therapy.

The large number of parameters makes it very difficult to objectify individual elements. Nevertheless, through the use of fluid mechanics experiments and numerics, individual parameters can be isolated and made accessible to an objective assessment. Of course, the optimization of individual elements will each have a different effect, so they must be mutually agreed.

The object of the present invention is to reduce energy consumption by reducing the total resistance coefficient and to reduce the development of noise by turbulence.

This object is achieved in that the flow path is formed as an airway in the ventilator and flow resistance of each formed as a molded body, component to achieve a low resulting total flow resistance of all components is optimized, wherein the flow path is provided in the region of at least one cross-sectional change with a flow ,

For this purpose, coordinated components are provided which do not necessarily have to fulfill an optimized property in the sense of their individual task, but which result in properties optimized for a respirator by the interaction of the entirety of the components.

• • Schaffung von strömungsoptimierten Oberflächen im gesamten Luftweg, beispielsweise ähnlich zu einer Haihaut,
• • Abstimmung der Übergänge/Schnittstellen im Sinne einer idealisierten Strömungsführung (keine Ecken und Kanten),
• • Berücksichtung physikalischer Gesetzmäßigkeiten im Sinne einer Verringerung des Strömungswiderstandes.

In particular, the following measures are used:

• Creation of flow-optimized surfaces in the entire airway, for example similar to a shark skin,
• • coordination of the transitions / interfaces in the sense of an idealized flow guidance (no corners and edges),
• • Consideration of physical laws in terms of reducing the flow resistance.

These specifications can be carried out, for example, on the following components: air inlet filter, air line in the ventilator, silencer, blower (optimization of the blade geometry, air baffles) air line to the patient, hose, patient interface, interfaces of the individual components.

In a ventilated patient, two systems - the respiratory system and the lungs - are connected. The connector of these systems is the tube and / or the patient interface (PI). In general, this connector has a smaller diameter than the part of the system before and after.

From this diameter dimensioning results in a significant flow resistance, which shows up as a pressure drop and can be quantified. It is defined as the pressure difference between the outer proximal end and the inner distal end of the tube.

To quantify this resistance, one can measure the pressure at each end and then calculate the resistance (ΔPPI PI = patient interface) from the measurements. Pprox is the pressure at the proximal end, Pdis the pressure at the distal end. This shows that it is a difference. The formula is: ΔPPI = Prox - Pdis

During inspiration, the pressure in front of the tube is greater than behind the tube. This results in a positive ΔPPI. During expiration, the higher pressure is found in the trachea, resulting in a negative ΔPPI. This difference depends on the internal diameter (ID) of the PI as well as on the flow (gas flow, F [l / s]).

• a) Patient
• b) Beatmungsgerät
• c) Beatmungsgerät und Patient

Measurements of the pressure drop of different PI at different flows give PI-specific pressure-flow-characteristics. The PI-induced pressure loss, means an additional, ineffective breathing work. This additional work of breathing must be done by:

• a) patient
• b) ventilator
• c) Respirator and patient

Should the patient measure the work, early respiratory fatigue threatens.

In the case of the takeover by the ventilation gag this must perform additional work in an inhalation, which can result in increased energy consumption, increased sound development and also a deteriorated control accuracy.

During the expiration the pressure in the PI has to be lowered in such a way that the exhalation is not obstructed and an effective CO2-elimination is possible.

A reduction of the flow resistance can take place in that the component has a surface profile.

In particular, it is contemplated that the surface profile has a lotus structure.

According to a further embodiment it is also provided that the surface profile has a sharkskin structure.

To form a laminar flow, it helps that the surface profile has longitudinal grooves.

For adaptation to actual flow velocities and volume flows, it is provided that the longitudinal grooves have different widths relative to each other.

According to a further embodiment, it is also contemplated that the longitudinal grooves have different distances relative to each other.

An embodiment is that the longitudinal grooves are formed as sawing.

Another design according to the invention is defined by the fact that the longitudinal grooves are formed as trapezoidal grooves.

Another design variant is that the longitudinal grooves are formed as L-grooves.

In order to avoid the formation of turbulence, it is important that at least two components have flow paths which are continuously diverted into each other.

A sound emission can be reduced by the fact that the flow path in the region of at least one cross-sectional constriction has a porous trailing edge.

To avoid turbulence, it also contributes that the flow path is provided in the region of at least one cross-sectional change with a flow guide.

A preferred embodiment is that the flow guide is designed as a brush edge.

According to another embodiment, it is also thought that the flow guide is formed as a soft blade.

A combination of different advantageous material properties can take place in that the flow guide is formed porous.

Another object of the invention is to construct a medical device such that improved functionality is provided.

This object is achieved in that at least one provided with a surface coating component is included and / or in that in the region of the surface functional properties, at least one flow-optimized surface, are provided.

In addition, an additional object of the present invention is to improve a method of the type mentioned above such that a functional and at the same time inexpensive and long-term functional embodiment is provided.

This object is achieved in that the molding is produced by means of plastic injection molding and coated at closing at least partially.

In principle, the use of surface-coated components in medical devices opens up an extremely wide range of constructive freedom. The particular desired functional properties can be provided by the surface coating, regardless of the material of the base body. The functional properties may relate, for example, to slip properties, friction properties, surface designs or surface hardnesses.

The surface coating of the base body is selected according to the given functional property and the base material of the base body can be determined independently of the desired functional property of the surface and of the mechanical or static boundary conditions. For example, it is possible to provide a hard base body with a softer surface coating at high mechanical loads or to equip a soft and elastic body with a germ-repellent functional surface. Optionally, the desired surface coatings are applied to the base bodies using suitable intermediate layers as adhesion promoters.

In a preferred embodiment, the molded body is essentially as a device part, device upper shell, device inner part, device accessory, device component, humidifier, nebulizer, medicament atomizer, ventilator, air inlet filter, muffler, airway in the device, filters, respiratory mask, breathing tube, emergency ventilation device, suction device, suction tube, collection container of a suction device or as a housing part formed.

Preferably, such a shaped body of a medical device is at least partially and / or partially made of plastic. There are often used different plastics. The plastics fulfill different functions and must be best suited for the function to be performed. For example, the plastics for a ventilator with the components inlet filter - respirator - output filter - patient tube filter - patient contact point are each optimized for the intended use.

As plastics all known plastics are conceivable. For example. polyethylenes, polypropylenes, polyvinyl chlorides, polystyrenes, polycarbonates, cellophanes, cellulose acetates, polyelofins, fluorinated hydrocarbons (Teflon), polyhydroxyethyl methacrylates (PHEMA) (hydron), polymethyl methacrylates (PMMA), polysiloxanes, polyethers, polyesters, polyacetals, polyvinyls, polyether silicones , Polyurethanes, Natural and Synthetic Rubber, Silicone, Latex, ABS Resin, Acrylic Resins, Triacetates, Vinylidene and Reyon.

Furthermore, all polymers suitable for injection molding of injection-molded bodies can be used. As materials for injection molding, preference is given to using polymers or polymer blends comprising a polymer based on polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, polyethylenes, polypropylenes, aliphatic linear or branched polyalkenes, cyclic polyalkenes, polystyrenes, polyesters , Polyethersulfones, polyacrylonitrile or polyalkylene terephthalates, poly (vinylidene fluoride), poly (hexafluoropropylene), poly (perfluoropropylene oxide), poly (fluoroalkyl acrylate), poly (fluoroalkyl methacrylate), poly (vinyl perfluoroalkyl ethers) or other polymers of perfluoroalkoxy compounds, poly (isobutene), poly (4 -methyl-1-pentene), polynorbornene homo- or copolymer or mixtures thereof. Very particular preference is given to using as the material for injection molding polymers or polymer blends comprising a polymer based on poly (ethylene), poly (propylene), polymethyl methacrylates, polystyrenes, polyesters, acrylonitrile-butadiene-styrene terpolymers (ABS) or poly (vinylidene fluoride). have, wherein the plastics know in pure form and / or as a mixture know. Polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, polyethylenes, polypropylenes, aliphatic linear or branched polyalkenes, cyclic polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates, pols (vinylidene fluoride), or other polymers of poly (isobutene), Poly (4-methyl-1-pentene), polynorbornene homo- or copolymer, a polymer based on polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, polyethylenes, polypropylenes, aliphatic linear or branched polyalkenes, cyclic, polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates, poly (vinylidene fluoride), or other polymers of poly (isobutene), poly (4-methyl-1-pentene), polynorbornene homo- or copolymer and mixtures thereof, and their mixtures.

In addition to plastics, it is also possible to use metals and / or ceramics and / or glass or any combination of these materials, including with the abovementioned plastics.

The surface may be completely or partially covered with the polymers.

It is possible to melt the polymer only and / or to apply it only so slightly to the surface, which possibly retains a grain structure of the polymer. It is achieved as a structuring of the surface.

According to the invention it is proposed to make the surfaces rough and hydrophobic. This may be a surface with an artificial surface structure of elevations and depressions, which also has self-cleaning properties. The surface structures are preferably in the nm to μm scale. Particularly preferably, the surface structures have a substantially similar distance from one another.

In addition, the surface may have particles which are fixed by means of a carrier system on the surface.

In this case, at least one surface of the shaped body made of a material selected from polymers, such as. As the polyamides, polyurethanes, polyether block amides, polyester amides, polyvinyl chloride, polyolefins, polysilicones, polysiloxanes, polymethylmethacrylates or polyterephthalates and metals, fibers, fabrics, glasses or ceramics made that has flow-optimizing properties.

For this purpose, the surface structure is produced by applying and fixing particles on the surface.

It is provided that the particles have a mean particle diameter of 0.05 to 2000 nm.

These particles form an irregular fine structure in the nanometer range on the surface.

In a preferred embodiment, it is provided that the shaped body has a structured surface with regular and / or irregular elevations and / or depressions in the nm and / or μM scale.

In this case, the surface has at least one firmly anchored layer of microparticles, which form elevations. The elevations have a mean height of 20 nm to 25 microns and a mean distance of 20 nm to 25 microns. However, an average height of 50 nm to 4 μm and / or an average distance of 50 nm to 4 μm is preferred.

Furthermore, it has self-cleaning properties and elevations formed by microparticles, wherein hydrophobic microparticles are pressed in to produce the surface of the surface extrudate. The microparticles used have an average particle diameter of 0.02 to 100 microns.

Furthermore, the invention includes structured surfaces with a low surface energy.

The present invention therefore structured surfaces having elevations with a mean height of 10 nm to 200 microns and a mean distance of 10 nm to 200 microns, and their outer shape by a mathematical curves and / or functions with a symmetry with respect to a Level.

A particularly low surface energy is particularly necessary if not only hydrophobic, but also oleophobic behavior is required. This is especially the case with non-solid, oily soils. (Lotus-Effect) (TM)

For the preparation, the structured, hydrophobic surface with elevations and depressions is mixed with an additive which has a particle size of 0.0001 to 20 μm and an organic matrix which has at least one thermoplastic, elastomeric or thermosetting plastic.

Preferred microparticles have an irregular fine structure in the nanometer range on the surface, a particle diameter of 0.02 to 100 .mu.m, particularly preferably from 0.1 to 50 .mu.m and very particularly preferably from 0.1 to 10 .mu.m. However, suitable microparticles may also have a diameter of less than 500 nm or be composed of primary particles to form agglomerates or aggregates having a size of 0.2 to 100 μm.

It may be advantageous if the microparticles have hydrophobic properties, wherein the hydrophobic properties may be due to the material properties of the materials present on the surfaces of the particles themselves or but can be obtained by treating the particles with a suitable compound. The microparticles may have been provided with functional properties before or after the application or bonding on or to the surface of the device or of the injection-molded body.

The invention further includes a process for the production of plastic granules and powders.

If products made of polyolefins are to be painted, printed, coated or glued, a pre-treatment of the molded parts is necessary since the non-polar surface of these plastics does not sufficiently adhere printing inks or adhesives. Common are thermal or wet chemical processes. The desired oxidation of the surface can also be achieved by means of an electronic plasma treatment.

A plasma process allows the treatment of polyolefin granules and powders, so that a subsequent treatment of the parts can be omitted. By means of an HF-CVD process, very thin nanolayers of, for example, polytetrafluoroethylene (PTFE, [Teflon]) can be deposited on various substrates. Thus, different material surfaces with any properties are functionalized.

The chemical sol-gel process in which nanomaterials are formed is a variant of inorganic synthetic chemistry that has hitherto been little used in materials development. It can be used to produce inorganic or inorganic organic materials from liquid starting materials via a low-temperature process and to make them broad in composition and structure.

The aim of the use of ceramics for nanostructuring of surfaces is to modify the properties of known materials or to provide known materials with new functions, for example to produce column structures in the range from 20 to 300 nanometers on metal and plastics by embossing processes. This leads to a change of the interface properties. The formation of hemispheres with a radius of 250 to 350 nanometers on, for example, glass surfaces significantly reduces their light reflection. This effect is based on the creation of a continuous transition between the surrounding air and the glass surface, which can only be achieved by nanostructures.

A combination of micro- and nanostructuring can be easily and easily used to modify the surfaces.

The application of the solvent having the particles on the polymer surface can, for. B. by spraying, knife coating, dripping or by immersing the polymer surface in the particles having solvent.

By means of the method according to the invention, it is possible to produce a flow-favorable polymer surface which has an artificial, at least partially hydrophobic surface structure of elevations and depressions, which are characterized in that the elevations and depressions are formed by particles fixed to the polymer surface.

The particles can also be present as aggregates or agglomerates, according to DIN 53 206 under aggregates surface or edge-shaped juxtaposed primary particles (particles) and under agglomerates punctiform mutually superposed primary particles (particles) are understood.

The structures described may, for. Example by an injection molding process in combination with a manufactured by LIGA process, conventional injection molding tool. The LIGA process is a structuring process based on basic processes of X-ray lithography, electroplating and impression taking. The method differs from micromechanics in that the structures are not produced by an etching process in the base material, but can be molded inexpensively via a tool. In the present case, the LIGA process is used to manufacture the tool.

Furthermore, unwanted changes in the physical properties of the substrates can largely be ruled out in this way since only a very thin layer on the surface of the substrate is changed. The process according to the invention can easily be combined with other surface treatment methods. So z. B. possible to perform a hydrophilization with water or acids after the thermally assisted application of the polymers.

The material properties of the various plastics are only insignificantly influenced. Characteristics such as continuous operating temperature, creep resistance, thermal and electrical insulation are retained. The compound can be used under all conceivable manufacturing, processing and application conditions. It is used in semi-finished products made of PEEK, PPSU, POM-C, PET as well as injection-molded parts, extruded profiles and calendered sheets.

• • Flammschutz
• • gleitreibungsarm
• • strömungsoptimiert
• • Korrosionsschutz
• • elektrochemisch aktive
• • reflektionsarm
• • elektrochrom
• • photochrom
• • piezoelektrisch
• • leitfähig
• • Kratzschutz
• • Antireflex

The shaped bodies according to the invention may alternatively and / or in addition to the aforementioned Properties have the following properties. It is also envisaged that a shaped body according to the invention can have at least some properties in several sections.

• • flame retardant
• • Low friction
• • flow-optimized
• • corrosion protection
• • electrochemically active
• • low reflection
• • electrochromic
• • photochromic
• • piezoelectric
• • conductive
• • Scratch protection
• • Anti-reflex

• • Plasmaverfahren
• • Laserverfahren
• • Sol-Gel-Verfahren
• • Galvanische Verfahren
• • Erzeugung von Nanostrukturen durch Selbstorganisation
• • Nanostrukturierung von Materialien und Oberflächen
• • Aufdampfen im Hochvakuum (Elektronenstrahlverdampfen)
• • Aufdampfen im Hochvakuum (Widerstandstiegelverdampfen)
• • Kathodenzerstäubung
• • CVD-Verfahren (Chemical Vapour Deposition)
• • PVD (Physical Vapour Deposition)
• • LIGA-Verfahren
• • Thermische Oxidation
• • Mikrogalvanik (Hartlegierungsabscheidungen)
• • Spritzguß von Mikrokomponenten aus Kunststoffen
• • Vakuumbeschichtung
• • chemisch galvanischen Beschichtung
• • lnmould-coating
• • Pre-coating

For the production of shaped articles according to the invention, the following methods may alternatively and / or additionally be used in addition to the abovementioned methods.

• Plasma process
• • Laser process
• • Sol-gel method
• • Galvanic process
• • Generation of nanostructures through self-organization
• • Nanostructuring of materials and surfaces
• Vapor deposition in a high vacuum (electron beam evaporation)
• Vapor deposition in a high vacuum (resistance crucible evaporation)
• • sputtering
• • CVD process (Chemical Vapor Deposition)
• • PVD (Physical Vapor Deposition)
• • LIGA procedure
• • Thermal oxidation
• • Microplating (hard alloy depositions)
• • Injection molding of microcomponents made of plastics
• • Vacuum coating
• • chemically galvanic coating
• • Inmould-coating
• • Pre-coating

In addition, the invention relates to a process for the preparation of moldings according to the invention. Advantageous embodiments of the method according to the invention are specified in the subclaims.

In the drawings, embodiments of the invention are shown schematically. Show it:

1 a surface design using sawing,

2 a surface design using trapezoidal grooves,

3 a surface design using L-grooves,

4 a block diagram illustrating the main functional components of a measuring device for flow resistance,

5 a table summarizing the flow resistance of different ventilation masks at different volume flows,

6 a graphic summary of the test results according to the table in 5 .

7 a flow-optimized arc angle,

8th a perspective view corresponding to viewing direction XIII in 7 .

9 one opposite the representation in 8th modified embodiment,

10 1 is a schematic representation for illustrating the formation of turbulences in the region of a cross-sectional constriction of the flow path,

11 one too 10 modified embodiment using brush-like transition elements,

12 a schematic representation of the flow guidance in the region of a cross-sectional enlargement using brush-like flow elements,

13 the arrangement according to 12 without the use of flow guide elements,

14 a diagram for summarizing the dependence of the flow resistance of the flow for different embodiments,

15 a medical device,

16 a perspective view of a humidifier, which is used between the ventilator and a breathing tube,

17 a ventilator with a connection valve for providing an increased oxygen concentration,

18 a perspective view of a respiratory mask with forehead support

19 a surface profile and

20 - 25 different surface topographies.

According to the embodiment in FIG 1 is used for the surface design of a flow path of the effect that can be reduced by fine longitudinal grooves in the surface of bodies flow around the flow resistance. In comparison to the 'smooth surface', resistance reductions of up to about 10% are measured. Resistant groove surfaces (riblets) are of interest where high surface quality requirements are imposed at higher flow rates. This is despite the fact that the grooves considerably increase the surface area of the body, and although, in the classical theory, the groove surface is a 'rough surface'. According to the invention it is proposed to equip the inner tube wall partially with grooves of different sizes and arrangements.

Resilient groove surfaces (riblets) consist of microscopic grooves aligned parallel to the flow. The grooves must be dimensioned to act as a hydraulically smooth surface for the flow. The resistance-reducing effect is a hindrance of the turbulent transverse portions of the flow on the wall. The riblet surfaces according to the invention can reduce the turbulent wall friction by up to 10%.

A correlation between flow velocity and groove spacing exists in that narrower grooves are more likely to be less than half the lateral wavelength and thus generate smaller turbulence. According to the invention, it is therefore proposed that the riblet surfaces in the area of the respirator have different riblet dimensions and / or different riblet spacings, depending on the prevailing flow conditions there.

The results of experiments show a 5-10% lower resistance of the scoring foil to a smooth structure.

The drag reduction by the groove structure can be explained by the appearance of different, structured subregions in the boundary layer. These boundary layers have an influence on the turbulence.

In the laminar underlayer of the flow, high speed streaks alternate with low speed streaks. These structures influence the turbulence behavior at the boundary layer. The distances of the stripes can be calculated as follows:
W = 100 l
l = v / Uτ
W - score distance
l - characteristic length of the lower layer
v - kinematic viscosity
Uτ - friction speed

The friction rate is defined as: Reynolds number = inertial forces / friction forces. It describes the hydrodynamic similarity of a body, depending on the viscosity of its surrounding medium.

According to the invention, the use of surfaces with high Reynolds numbers is provided. The inertia of the medium is the same, high Reynolds numbers are achieved by very low frictional forces in the area of the surface. These are achieved by the characteristic ridge structure.

In summary, in regions of faster flow, grooves are used at a smaller distance than in areas with slow flow; the grooves are aligned along the flow and overlap each other.

Another aspect of the invention is that the surfaces according to the invention hardly pollute, so it is a lotus effect observed.

The air resistance can be described by the formula W = Rho / 2 * cw * A * V ² .

If you want to achieve a faster flow with a certain power, then this can be done by reducing the cw value and the area A (the air density Rho is given by air pressure and temperature). While the area can only be reduced to a certain extent, the cw value has extreme potential. The air resistance W can be decomposed into a pressure and a friction component.

The pressure resistance includes shape errors and resulting vortices. If no complete pressure compensation takes place due to flow separations, a resistance force called pressure resistance arises. However, perfect shaping can reduce it to a minimum.

Another object of the present invention is to make the shape close to the absolute optimum so that the "streamlines" close again with almost no pressure losses / swirls. This increases the proportion of friction, which therefore must be paid more attention here. Of the Frictional resistance arises from shear stresses between the body and the medium flowing around it.

The frictional resistance can be broken down into a laminar and a turbulent fraction. In the front part of the cladding, the flow is initially laminar, but then bends depending on the shape and surface at one point in turbulent flow, which means a significant increase in resistance in the following area. Consequently, it is necessary to try to keep the flow in the boundary layer as laminar as possible for as long as possible. This can be achieved by the use of laminar profiles, where the largest width is reached at the earliest at 50% of the total length, whereby the flow is accelerated longer and can be kept easier laminar on this acceleration section.

Another way to keep the flow laminar is to optimize the front surface by, for example, riblet surfaces. If, on the other hand, the flow has been torn off by a shape error at a certain point, then by increasing the roughness in this region, it is possible to recapture the flow through this defined energy supply and thus to reduce the resistance (the pressure resistance).

Alternatively, the turbulent part of the boundary layer can be at least partially laminarized by discharging "mini-vortexes" created by small holes in the surface.

According to the invention, an application of the numerical fluid mechanics is also intended to detect wall shear stress, friction coefficients, wall friction, air resistance and their absolute value to the total resistance.

In 1 becomes a component ( 1 ) of a respirator, which in the region of a surface ( 2 ) with a surface profile ( 3 ) is provided. The surface profile ( 3 ) consists of surveys ( 4 ), the groove-like depressions ( 5 ) limit.

The embodiment according to 1 shows a course of the surface profile ( 3 ) with Sägerillen, which extend in a flow longitudinal direction. The surveys ( 4 ) and the depressions ( 5 ) each span angles of about 60 degrees. The breadth of the surveys ( 4 ) and the depressions ( 5 ) is chosen substantially the same.

2 shows an embodiment of the surface profile ( 3 ) in the form of trapezoidal grooves. The surveys ( 4 ) are essentially corresponding 1 formed, however, have a narrower opening angle of about 45 ° degrees. The distance between the upper extensions of two elevations ( 4 ) is about twice the level of the surveys ( 4 ).

3 shows an embodiment in which the surface profile ( 1 ) consists of L-grooves. Over the surface ( 2 ) rise here web-like projections. A distance of the respective webs is about twice the web height.

4 shows a basic structure of a device for measuring flow resistance. A flow source ( 6 ) is connected to a flowmeter ( 7 ) connected. Behind the flowmeter ( 7 ) is a valve ( 8th ) arranged. To a connecting line between the flowmeter ( 7 ) and the valve ( 8th ) is a pressure gauge ( 9 ) connected.

5 summarizes tabulated measurement results obtained using the measuring device according to 4 were determined. Using the example of eight respiratory masks, the flow resistance of different patient interfaces was determined. In this case, the total flow resistance of the individual masks was determined. The test specimens 1 to 6 represent masks according to the known prior art, the test specimens 7 and 8 were optimized according to the invention with regard to the flow guidance. Specifically, the following samples were measured using the measurement setup according to 4 examined:
DUT 1 ResMed; Mirage (from current series)
Test item 2 ResMed; Ultra Mirage (from current series)
Examinee 3 Respironics; Comfort Select (from current series)
DUT 4 MAP; Papillon (from current series)
Examinee 5 Weinmann; SOMNO mask (from current series)
Examinee 6 Weinmann; SOMNO plus (from current series)
Examinee 7 Weinmann; vented (near-series prototype)
Examinee 8 Weinmann; nonvented (near-series prototype)

As test equipment was the Timeter PM no. 107-015 used as a flowmeter. As pressure gauge came the SI PM no. 205-029 used. In addition, the use of a Weinmann type SOMNOcomfort device modified to allow the setting of a constant speed was carried out. The in 4 illustrated experimental design will be further explained below.

The flow resistance of the specimens was measured for the volume flows 50 l / min and 100 l / min. The measure of the flow resistance is the height of the dynamic pressure in front of the test object compared to the ambient pressure. The dynamic pressure is passed through a thin tube, which is connected to the test object on the flow channel, to the pressure gauge and measured there. The two volume flow rates (50 l / min and 100 l / min) were generated by a modified SOMNOcomfort, whose speed can be set constant, and checked by Timeter. All wanted (outflow) and unwanted (interfaces, eg between angle and rotating sleeve) openings were sealed before starting the measurement.

6 summarizes the test results 5 for the flow rates of 50 and 100 l / min together. The registered numbers of the individual candidates correspond to the numbers in 5 , It can be seen that, in particular in the case of the test specimen No. 7, the flow resistance with respect to the best comparison device of the prior art could be further halved by the construction according to the invention.

In addition to the surface design according to the invention also the flow control is of considerable importance. In particular, in the case of a patient interface in the form of a mask, an angle-shaped connecting piece is frequently used for connection to the breathing tube. The geometry of the angle and the hose connection represent a significant influencing factor for the resulting flow resistance. With regard to the reduction of the flow resistance, a connection angle of <70 ° degrees and a connection diameter> 18 mm proves to be particularly advantageous. By reducing the flow resistance, the pressure generated by the ventilator comes directly to the patient. The reduction of the flow resistance thus contributes to an improved implementation of the therapy. In addition, the control accuracy can be increased and energy savings can be achieved.

7 shows an intended for connection to a breathing mask, not shown, angular fitting ( 10 ), which with a ball joint ( 11 ) is provided. The arc angle is about 70 degrees.

8th shows the connector ( 10 ) according to 7 according to the viewing direction VIII in 7 , The diameter at the narrowest point is about 15.2 mm.

9 illustrates that the narrowest point of the fitting ( 10 ) has an area of about 210 mm ² .

The importance of a fluid mechanical shape optimization decreases nonlinearly with the flow velocity. However, especially in the area of high ventilation pressures and high flows, the influence of a fluid-favorable form is particularly energy-saving, reduces sound and increases the quality of the therapy.

Further investigations aimed at reducing the radiation efficiency of overflowed edges. Sound is created at overflowed edges by converting part of the turbulent wall pressure fluctuations into propagatable pressure waves. Since this process is causally related to the unsteady change of the boundary conditions at the edge, a change of the edge properties in the sense of a more steady transition from the hard wall to the free flow was regarded as a potential solution for noise reduction.

10 shows a flow path ( 12 ) with a main flow direction ( 13 ). In mainstream direction ( 13 ) the respiratory gas flow first passes through a first cross-sectional area ( 14 ) and then a second cross-sectional area ( 15 ). The first cross-sectional area ( 14 ) is characterized by a step-shaped rejuvenation ( 16 ) in the relative to the first cross-sectional area ( 14 ) smaller second cross-sectional area ( 15 ). 10 shows that in such a rejuvenation of the rejuvenation ( 16 ) generated turbulences ( 17 ).

In 11 are used to avoid turbulence ( 17 ) Flow guide elements ( 18 ) used. The practical implementation took place in the form of a main flow direction ( 13 ) aligned brush attachment at the upper edge. A reduction of the noise by 2 to 3 dB was achieved. Noise reduction is observed mainly at low frequencies.

An adaptation to the respective application requirements can be achieved by the geometry of the flow guide elements (FIG. 18 ) respectively. In particular, the thickness, the density, the length and the flexibility can be varied. Particularly significant was the flexible design of the flow guide elements ( 18 ).

According to a further embodiment, it is also contemplated, alternatively or in addition to the flow guide ( 18 ) flow-optimized trailing edges ( 19 ) to use. Outflow edges ( 19 ) made of a porous material. It is also conceivable, the flow guide elements ( 18 ) from a porous or open porous material. Ideally, this is done in combination with a further flexible design of the flow guide elements ( 18 ). The use of the flow guide elements ( 18 ) led experimentally to a noise reduction of up to 12 db.

Another field of application for the optimization of the flow control relates to the generation of respiratory gas and the components used for this purpose. The rotor of the fan is the most important sound source and shows a strong dependence on the gap width to the rotor boundaries. By systematically reducing the gap width (up to 85% of the initial state), a considerable reduction in noise could be achieved, caused in large part by the lowering of the discharge velocity at the trailing edge associated with the gap narrowing.

The bleed noise at the end and side edges and the transitions can be significantly reduced by suitable edge shaping (eg brushes, porous end edges).

12 shows the use of flow guide elements ( 18 ) in the transition region from a first cross-sectional area ( 14 ) to a second cross-sectional area ( 15 ), wherein the second cross-sectional area ( 15 ) larger than the first cross-sectional area ( 14 ) is trained. The first cross-sectional area ( 14 ) is of a heel-like extension ( 20 ) in the second cross-sectional area ( 15 ). The flow guide elements ( 18 ) extend from one edge ( 21 ) of the first cross-sectional area ( 14 ) in the flow area of the second cross-sectional area ( 15 ) into it.

13 shows the arrangement according to 12 without the use of flow guide elements ( 18 ). It is the resulting turbulences ( 17 ) to recognize.

Measurements of the pressure drop of differently optimized ventilators at different flows give specific pressure-flow characteristics. 14 shows pressure-flow characteristics for different ventilators. The horizontal scale shows the flow (flow rate) in liters / second, the vertical scale shows the pressure loss APPI in mbar. During inspiration there is a positive flow and a positive pressure difference, during expiration there is a negative flow and a negative pressure difference.

14 shows that the pressure difference does not change strongly at a flow between 0 and 25 l / min, but then increases significantly with each increase in speed. This can be explained by the fact that the air flows laminar at a low flow up to about 20 l / min, but turbulence occurs at higher flows, which increases the resistance. The flow changes with each phase of a breath. With moderate ventilation, the pressure loss is between 0 and 10 mbar. With increased ventilation, this pressure loss can be up to 25 mbar.

• a – normal
• b – Bürsten
• c – Haihaut
• d – Geometrie des Anschlußstückes PI – Schlauch
• e – Bürsten + Haihaut + Geometrie des Anschlußstückes PI – Schlauch

The different lines in 14 represent the pressure-flow characteristics for differently optimized ventilators.

• a - normal
• b - brushes
• c - shark skin
• d - geometry of the connector PI - hose
• e - brushes + shark skin + geometry of the fitting PI - hose

• a) Patient
• b) Beatmungsgerät
• c) Beatmungsgerät und Patient.

The pressure loss means an additional, ineffective work of breathing. This additional work of breathing must be done by:

• a) patient
• b) ventilator
• c) Respirator and patient.

Should the patient have to do the work, premature respiratory fatigue is imminent. In the case of takeover by the ventilator this must perform additional work in a Binatmung, which can result in increased energy consumption, increased sound development and also a deteriorated control accuracy. During the expiration the pressure in the PI has to be lowered in such a way that the exhalation is not obstructed and an effective CO2-elimination is possible.

15 shows the basic structure of a device for ventilation. In the area of a device housing ( 22 ) with control panel ( 23 ) as well as display ( 24 ) is arranged in a device interior, a breathing gas pump. Via a coupling ( 25 ) is formed as a connecting hose connection line ( 26 ) connected. Along the connecting tube ( 26 ), an additional pressure measuring hose ( 27 ), which via a pressure input port ( 28 ) with the device housing ( 22 ) is connectable. To enable data transmission, the device housing ( 22 ) an interface ( 29 ) on.

In the area of the device housing ( 22 ) facing away from the expansion of the connecting line ( 26 ) is an exhalation element ( 30 ) arranged. Also, an exhalation valve can be used.

15 also shows a ventilation mask ( 31 ), which is designed as a nasal mask. A fixation in the region of a head of a patient can be achieved via a hood ( 32 ) respectively. In the area of their connection hose ( 26 ) facing the respiratory mask ( 31 ) a coupling element ( 33 ) on.

The surface coatings can be prepared in different methods, some of which have already been exemplified above. The surface coatings can are generated by the described incorporation of particles, but there are also vapor depositions, laminations or plasma coatings used. Likewise, the already explained methods for applying liquid coatings in pure form or diluted with solvents can be used. Also surface treatments, for example using mechanical means, laser or electron beams are possible.

19 shows a portion of a surface profile of a modified molded article for a medical device with surveys of various shapes having a height with respect to the background of 0.1 nm to 5000 nm. The distance from the individual elevations is also in the range of 0.1 nm to 5000 nm.

These elevations are arranged in various forms forming regular structures on the surface.

The invention includes in one embodiment, for example, the following accessories that can be used in the field of ventilation:
Humidifier ( 16 ), O2 valve ( 17 ), Hood, patient interface (for example, mask, nasal pillows, tube) hose, filter, bracket, clutch, heater, change parts, bag. In the following it will be explained how the invention contributes to the improvement of said accessories.

With ventilators, an air volume flow of up to 400 l is generated per minute. The dimensions of a ventilator, the patient tube and the patient interface are essentially fixed within narrow limits. The energy required to generate the air flow therefore increases disproportionately with increasing flow velocity. At the same time, the noise increases with increasing flow velocity.

The reduction in noise measured at 1 meter distance may typically be at least 5% or at least 1 dB (A). With regard to a reduction of the required energy requirement is especially thought that the reduction is at least 2%. Another variant is that the reduction of a time required for a required cleaning is at least 10%.

According to the invention it is therefore proposed to reduce the frictional force of the surfaces in order to save energy and / or limit the noise. The resistance-reduced surfaces according to the invention consist of microscopically small structures of the surface, for example grooves, which are preferably aligned parallel to the flow of the medium. Such surfaces are known from nature, for example from the shark skin. The surface structures are to be dimensioned to act as a hydraulically smooth surface for the flowing medium. The resistance-reduced effect consists in a hindrance of the turbulent portions of the flow on the wall.

Preferably, the surface structures have a substantially equal distance from each other, which is in the range 100 nm-200 microns. Particularly preferred in the range 5 microns to 100 microns. Particularly preferably, the surfaces according to the invention have a resistance reduction in the range of> 1.0%.

According to the invention, the air-carrying part of a respirator and / or hose at least in sections has a structured surface with regular and / or irregular elevations and / or has a surface which reduces the friction of a flowing medium and / or has a flow-optimized surface.

To avoid dehydration of the respiratory tract, humidification of the respiratory air is typically carried out. Since patients perceive heated air as pleasant and because by heating, for example by means of a heating element ( 35 ), the air can absorb more water vapor, typically a heating as a liquid reservoir ( 36 ) used water supply of the humidifying system indirectly and / or directly, for example via the metallic bottom of the water supply or for example by means of a heating element ( 35 ) directly in the water. A breathing gas humidifier can be connected via a coupling ( 25 ) externally connected to a respirator and / or disposed within a ventilator. Due to the hygienic requirements to be complied with the humidifier must be removable for cleaning and still ensure adequate sealing against the water. The humidifier is divided into a, substantially air-conducting, upper part ( 38 ), which also connects the ventilator ( 22 ) and connecting hose ( 26 ), and a lower part ( 39 ) that can hold the water supply. In the area of the upper part ( 38 ) is a filling opening for liquid ( 40 ) with closure ( 41 ) arranged.

In the area of the humidifier, a gas line ( 42 ), which is preferably designed as Druckmeßleitung and / or oxygen supply. The gas line is via a gas coupling ( 43 ) connected to the humidifier. The humidifier is connected via a connection adapter ( 44 ) with a connecting hose ( 26 ) can be coupled. A communication with the ventilator ( 22 ) can be connected via an existing connector ( 45 ) between the humidifier and the ventilator. In the area of the moistener, an ad ( 46 ).

17 shows a perspective view of a ventilator ( 22 ) coupled with a coupling ( 25 ), a control panel ( 23 ) is provided. With the coupling ( 25 ) is a connecting tube ( 26 ), through which a Druckmeßleitung ( 27 ) extends therethrough.

On the outside of the connection hose ( 26 ) is an oxygen line ( 49 ), which are equipped with an oxygen connection valve ( 47 ) connected is. The connection valve ( 47 ) is via a supply line ( 50 ) connected to an oxygen source, not shown. Via a control line ( 51 ) is the connection valve ( 47 ) with an interface ( 29 ) of the ventilator ( 22 ) connected.

At the in 17 illustrated embodiment, the sequence valve ( 47 ) on the outside of the ventilator ( 22 ) arranged. However, it is also thought to integrate the Zuschaltventil in the ventilator.

The oxygen-switching valve may preferably have a self-cleaning and / or hydrophilic and / or oleophobic and / or low-friction and / or conductive surface.

As a next application example, a patient interface will be explained below. According to the in 18 illustrated embodiment, a patient interface as a face mask ( 31 ). Usually a mask is designed as a modular system and typically consists of the following components, this list is not exhaustive:
Mask body ( 52 ) and / or mask bead ( 53 ) and / or exhalation system ( 54 ) and / or coupling element ( 33 ) and / or joint ( 55 ) and / or forehead support ( 56 ) and / or holder of the forehead support ( 57 ) and / or forehead pads ( 58 ) and / or fastening device ( 62 ) for a headband circlip and / or ripcord. Not all individual components must necessarily be arranged in the region of a mask, so that it is functional.

The mask bead ( 53 ) is designed to fit on the face of a patient and ensures the required seal. About a joint of the mask body with a coupling element ( 33 ), which serves for connection to a breathing gas hose. To ensure a secure positioning of the breathing mask in the head region of a patient, a forehead support ( 57 ) used with a forehead pad ( 58 ) Is provided. The forehead support is via a holder ( 53 ) connected to the mask body.

As an alternative to a mask, various other patient interfaces are used. Examples include the following: nasal pillows, tubes, tracheostoma, catheter.

In the following, masks and all mask components, as well as other patient interfaces, such as Nasal pillows, are simplified in the term patient interfaces.

Patient interfaces may preferably at least in sections have a germ-repellent and / or self-cleaning and / or hydrophobic and / or oleophobic and / or photocatalytic and / or scratch-resistant and / or anti-fogging and / or skin-friendly and / or low-friction and / or electrically conductive surface.

It is particularly preferred to provide patient interfaces in the region of their side facing the air flow by suitable smooth plastics and / or coated surfaces and / or coated plastics and / or surfaces structuring on the nanometer to micrometer scale equip in such a way that thereby a reduced Friction can be achieved.

The invention can also be used in conjunction with a filter. Especially in respirators, but also in other medical devices, filters are mainly used in the intake of the air to retain suspended matter, dust particles, microorganisms. With the help of the filters impurities of the device and the contamination of the patient should be avoided. Alternatively and / or additionally, filters are also used in the area between the device and the patient or user, in particular in order to avoid hygienic contamination. Usually, the filters are used interchangeably as plug-in filters. Also called combination filters are used, which may be formed, for example, as coarse and fine filters. If a filter is not regularly cleaned and / or replaced, retained particulate matter, dust particles, microorganisms can increase the flow resistance of the filter, which leads to a decrease in the performance of the device or contamination to the patient. Filters of the prior art must be replaced frequently, which is time consuming and expensive.

According to the invention, it is intended to equip the filters with functional surfaces. This allows a longer operating time of the filters, which helps to save costs.

Preference is given to filter in the area of your air flow side facing by suitable smooth plastics and / or painted surfaces and / or coated plastics and / or surfaces structuring on the nanometer to micrometer scale equipped in such a way that thereby achieves a reduced friction can be. Preference is likewise given to equipping so-called HME filters (heat moisture exchange) in such a way that they have a reduced frictional resistance and / or are germ repellent and / or self-cleaning and / or oleophobic and / or photocatalytic.

Functional surfaces are also beneficial for hoses. Especially in ventilators, but also in other medical devices such as suction devices hoses are used especially in the field of a connection between the user / patient with the device to direct a medium. Usually, the hoses are used interchangeably as plug-in hoses. If a hose is not regularly cleaned and / or replaced, retained particulate matter, dust particles, contaminants, microorganisms can increase the flow resistance, which leads to a decrease in the performance of the device or contamination to the patient. Hoses according to the prior art must be cleaned and / or replaced frequently, which is time consuming and costly. The cleaning must be done frequently and thoroughly to effectively remove contaminants.

The invention is intended to equip the tubes with functional surfaces. As a result, a longer operating life of the hoses is possible at the same time less time spent on cleaning, which saves costs.

Preference is given to hoses in the area of your air flow / media flow side facing by suitable smooth plastics and / or painted surfaces and / or coated plastics and / or surfaces structuring on the nanometer to micrometer scale to equip such a way that thereby reduced Friction can be achieved. It is also preferred that hoses have an electrically conductive surface.

Claims (3)

Device for ventilation, which is designed as a ventilator and has at least one flow path and which consists of a plurality of interconnected components, which are arranged along the flow path one behind the other and through which the flow path passes, characterized in that the flow resistance of each individual component ( 1 ) to achieve a low resulting total flow resistance of all components ( 1 ), wherein the flow path ( 12 ) in the region of at least one cross-sectional change with flow guide elements ( 18 ) and the cross-sectional change as a heel-shaped extension ( 20 ) is formed, which has a first cross-sectional area ( 14 ) in a second cross-sectional area ( 15 ), whereby the flow guiding elements ( 18 ) starting from an edge ( 21 ) of the first cross-sectional area ( 14 ) in the flow area of the second cross-sectional area ( 15 hineinerstreckt and wherein the flow guide elements ( 18 ) are formed as brush edges or as soft fins or of an open-pore material. Device according to claim 1, characterized in that at least two components ( 1 ) have continuously flowed into each other flow paths. Device according to one of claims 1 or 2, characterized in that the flow path ( 12 ) in the region of at least one cross-sectional narrowing a porous trailing edge ( 19 ) having.

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