U.S. patent application number 11/660173 was filed with the patent office on 2008-04-03 for respirator.
Invention is credited to Martin Bechtel, Martin Eifler, Karl Andreas Feldhahn, Arnold Frerichs, Thomas Marx, Gerd Schulz.
Application Number | 20080078386 11/660173 |
Document ID | / |
Family ID | 34978741 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080078386 |
Kind Code |
A1 |
Feldhahn; Karl Andreas ; et
al. |
April 3, 2008 |
Respirator
Abstract
Disclosed is a respirator comprising at least one flow path.
Said respirator is composed of several interconnected components
which ar disposed one behind another in the flow path and through
which the flow path extends. The fluid resistance of each
individual component is optimized so as to obtain a low total fluid
resistance of all components.
Inventors: |
Feldhahn; Karl Andreas;
(Hamburg, DE) ; Schulz; Gerd; (Schenefeld, DE)
; Marx; Thomas; (Hamburg, DE) ; Frerichs;
Arnold; (Buxtehude, DE) ; Eifler; Martin;
(Gluckstadt, DE) ; Bechtel; Martin; (Winsen/Luhe,
DE) |
Correspondence
Address: |
FRIEDRICH KUEFFNER
317 MADISON AVENUE, SUITE 910
NEW YORK
NY
10017
US
|
Family ID: |
34978741 |
Appl. No.: |
11/660173 |
Filed: |
September 2, 2005 |
PCT Filed: |
September 2, 2005 |
PCT NO: |
PCT/DE05/01549 |
371 Date: |
February 14, 2007 |
Current U.S.
Class: |
128/204.18 |
Current CPC
Class: |
A61M 16/0875 20130101;
A61M 16/16 20130101; A61M 2202/20 20130101; A61M 16/107 20140204;
A61M 16/0858 20140204; A61M 16/12 20130101; A61M 16/0655 20140204;
A61M 16/0825 20140204; A61M 2202/20 20130101; A61M 16/0638
20140204; A61M 16/06 20130101; A61M 16/0633 20140204; A61M
2205/0238 20130101; A61M 2205/0205 20130101; A61M 16/0694 20140204;
F16L 11/12 20130101; Y10T 428/26 20150115; A61M 16/0683 20130101;
A61M 2202/0078 20130101 |
Class at
Publication: |
128/204.18 |
International
Class: |
A61M 16/00 20060101
A61M016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2004 |
DE |
10 2004 043 208.2 |
Mar 18, 2005 |
DE |
10 2005 013 079.8 |
Jun 14, 2005 |
DE |
10 2005 027 724.1 |
Claims
1. A ventilator, which has at least one flow path and comprises
several interconnected components, which are successively arranged
along the flow path, which runs through these components, wherein
the flow resistance of each individual component (1) is optimized
to achieve a low resultant total flow resistance of all components
(1).
2. A ventilator in accordance with claim 1, wherein the component
(1) has a surface profile (3).
3. A ventilator in accordance with claim 1, wherein that the
surface profile (3) has a lotus structure.
4. A ventilator in accordance with claim 1, wherein the surface
profile (3) has a shark skin structure.
5. A ventilator in accordance with claim 1, wherein the surface
profile (3) has longitudinal grooves.
6. A ventilator in accordance with claim 5, wherein the
longitudinal grooves have different widths relative to one
another.
7. A ventilator in accordance with claim 5, wherein the
longitudinal grooves are separated from one another by different
distances.
8. A ventilator in accordance with claim 5, wherein the
longitudinal grooves are formed as sawtooth grooves.
9. A ventilator in accordance with claim 5, wherein the
longitudinal grooves are formed as trapezoidal grooves.
10. A ventilator in accordance with claim 5, wherein the
longitudinal grooves are formed as L-shaped grooves.
11. A ventilator in accordance with claim 1, wherein at least two
components (1) have flow paths with a continuous transition into
each other.
12. A ventilator in accordance with claim 1, wherein the flow path
(12) has a porous trailing edge (19) in the vicinity of at least
one cross-sectional constriction.
13. A ventilator in accordance with claim 1, wherein the flow path
(12) is provided with a flow guide element (18) in the vicinity of
at least one cross-sectional change.
14. A ventilator in accordance with claim 13, wherein the flow
guide element (18) is designed as a brush-shaped edge.
15. A ventilator in accordance with claim 13, wherein the flow
guide element (18) is formed as a soft lamella.
16. A ventilator in accordance with claim 13, wherein the flow
guide element (18) is porous.
17. A ventilator in accordance with claim 1, with a molded body,
especially as a part of an apparatus or as a component or accessory
part of a medical device for ventilation, sleep therapy,
cardiotherapy and/or cardiovascular therapy, emergency supply, or
oxygen supply, including diagnostics in all of the specified areas,
wherein at least certain sections of its surface have a functional
property or impart a functional property.
18. A molded body in accordance with claim 1, wherein the
functional property is of a physical nature or has a physical
effect.
19. A molded body in accordance with claim 1, wherein the
functional property is at least also physical in nature or at least
also has a physical effect.
20. A molded body in accordance with claim 1, wherein the
functional property consists in an effect that reduces surface
adhesion.
21. A molded body in accordance with claim 1, wherein the
functional property consists in an effect that lowers the surface
energy or the flow resistance of the surface or in an effect that
lowers the noise generation of liquids or gases flowing along the
surface.
22. A molded body in accordance with claim 1, wherein the
functional property consists in an effect that lowers the kinetic
friction on or at the surface.
23. A molded body in accordance with claim 1, wherein the
functional property consists in an effect that alters (makes easier
or more difficult) the wettability or the fogging tendency.
24. A molded body in accordance with claim 1, wherein the
functional property consists in a hydrophilic effect.
25. A molded body in accordance with claim 1, wherein the
functional property consists in an oleophobic effect.
26. A molded body in accordance with claim 1, wherein the
functional property consists in an effect that enhances the
self-cleaning ability.
27. A molded body in accordance with claim 1, wherein the
functional property consists in an antireflective effect or in an
effect that lowers surface reflection at least for certain
wavelengths and/or certain polarizations and/or certain angles of
incidence.
28. A molded body in accordance with claim 1, wherein the given
functional property is already realized by suitable formation of
one or more limited parts or sections of the surface of the molded
body.
29. A molded body in accordance with claim 1, wherein at least two
of the functional properties selected from the group consisting of
a) wherein the functional property is of a physical nature or has a
physical effect; b) wherein the functional property is at least
also physical in nature or at least also has a physical effect; c)
wherein the functional property consists in an effect that reduces
surface adhesion; d) wherein the functional property consists in an
effect that lowers the surface energy or the flow resistance of the
surface or in an effect that lowers the noise generation of liquids
or gases flowing along the surface; e) wherein the functional
property consists in an effect that lowers the kinetic friction on
or at the surface; f) wherein the functional property consists in
an effect that alters (makes easier or more difficult) the
wettability or the fogging tendency; g) wherein the functional
property consists in a hydrophilic effect; h) wherein the
functional property consists in an oleophobic effect; i) wherein
the functional property consists in an effect that enhances the
self-cleaning ability; j) wherein the functional property consists
in an antireflective effect or in an effect that lowers surface
reflection at least for certain wavelengths and/or certain
polarizations and/or certain angles of incidence are simultaneously
realized in the molded body, at least with respect to the same part
or section of the surface.
30. A molded body in accordance with claim 1, wherein at least two
of the functional properties selected from the group consisting of
a) wherein the functional property is of a physical nature or has a
physical effect; b) wherein the functional property is at least
also physical in nature or at least also has a physical effect; c)
wherein the functional property consists in an effect that reduces
surface adhesion; d) wherein the functional property consists in an
effect that lowers the surface energy or the flow resistance of the
surface or in an effect that lowers the noise generation of liquids
or gases flowing along the surface; e) wherein the functional
property consists in an effect that lowers the kinetic friction on
or at the surface; f) wherein the functional property consists in
an effect that alters (makes easier or more difficult) the
wettability or the fogging tendency; g) wherein the functional
property consists in a hydrophilic effect; h) wherein the
functional property consists in an oleophobic effect; i) wherein
the functional property consists in an effect that enhances the
self-cleaning ability; j) wherein the functional property consists
in an antireflective effect or in an effect that lowers surface
reflection at least for certain wavelengths and/or certain
polarizations and/or certain angles of incidence are separately
realized in the molded body, at least with respect to two separate
parts or sections of the surface.
31. A molded body in accordance with claim 29, wherein the multiple
functional properties are produced with the same material or with
the same method of surface shaping or treatment or with an
analogous (physical, chemical, or biological) effective
mechanism.
32. A molded body in accordance with claim 1, wherein the
functional properties or at least one of the specified functional
properties is produced or enhanced with at least two different
materials or with at least two different methods of surface shaping
or treatment used together or with at least two different
(physical, chemical, or biological) effective mechanisms used
together.
33. A molded body in accordance with claim 1, wherein the molded
body is transparent, at least partially or at least in certain
sections, even in the area of the functional surface.
34. A molded body in accordance with claim 1, wherein the molded
body consists at least partially of plastic or consists of plastic
in certain sections.
35. A molded body in accordance with claim 1, wherein the surface
of the molded body contains a polymer as an active substance at
least partially or in certain sections.
36. A molded body in accordance with claim 1, wherein the surface
of the molded body is furnished with a coating.
37. A molded body in accordance with claim 36, wherein at least a
portion or section of the surface of the molded body has a surface
energy of less than 35 mN/m.
38. A molded body in accordance with claim 1, wherein at least a
portion or section of the molded body has a textured surface with
regular elevations or depressions.
39. A molded body in accordance with claim 1, wherein at least a
portion or section of the molded body has a textured surface with
irregular elevations or depressions.
40. A molded body in accordance with claim 1, wherein at least a
portion or section of the molded body has a textured surface with
both regular and irregular elevations or depressions.
41. A molded body in accordance with claim 38, wherein the
elevations and/or depressions have a height or depth of 5 nm to 200
.mu.m and/or are separated by a distance of 5 nm to 200 .mu.m.
42. A molded body in accordance with claim 38, wherein the
elevations and/or depressions have a height or depth of 20 nm to 25
.mu.m and/or are separated by a distance of 20 nm to 25 .mu.m.
43. A molded body in accordance with claim 38, wherein the
elevations and/or depressions have a height or depth of 50 nm to 4
.mu.m and/or are separated by a distance of 50 nm to 4 .mu.m.
44. A molded body in accordance with claim 1, wherein the molded
body is an apparatus casing, a hose, a gas or liquid line or flow
control system, a gas or liquid reservoir, a patient interface, an
atomizer, a nebulizer, a humidifier, an oxygen valve, a filter, a
sound absorber, a suction device, a collecting container, or a
defibrillator housing, or a part, a component, or an accessory part
(including fastening, conveying, and storage devices) of any of the
devices specified above.
45. A molded body in accordance with claim 1, wherein the
generation of noise in at least one operating variant is
simultaneously reduced by the functional property.
46. A molded body in accordance with claim 45, wherein the
reduction of noise generation, measured at a distance of 1 meter,
is at least 5% or at least 1 dB(A).
47. A molded body in accordance with claim 1, wherein the power
consumption in at least one operating variant is simultaneously
reduced by the functional property.
48. A molded body in accordance with claim 47, wherein the
reduction of power consumption is at least 2%.
49. A medical apparatus for ventilation, sleep therapy, emergency
supply, or oxygen supply with several molded bodies in accordance
with claim 1, wherein the functional property is realized in
several molded bodies, independently of the material that is used
or the physical, chemical, or biological surface shaping or
treatment.
50. A medical apparatus for ventilation, sleep therapy, emergency
supply, or oxygen supply with several molded bodies in accordance
with claim 1, wherein the functional property is realized in
several molded bodies, independently of the material that is used
but with the same-physical, chemical, or biological surface shaping
or treatment.
51. A method for producing a molded body or a medical apparatus in
accordance with claim 1, wherein the molded body is produced by
plastic injection molding, and then at least certain sections of
the molded body are coated.
52. A method in accordance with claim 51, wherein microparticles
are used which have a particle diameter of 0.02 to 100 .mu.pm,
preferably 0.1 to 50 .mu.m, and especially 0.1 to 10 .mu.m.
53. A method in accordance with claim 51, wherein a solvent that
contains particles is applied by spraying, doctoring, dropping, or
immersing.
54. A method in accordance with claim 51, wherein the surface is
rendered hydrophilic.
55. A method in accordance with claim 51, wherein the particles are
pressed into the surface.
56. A method in accordance with claim 55, wherein a mold is
provided with particles before the injection molding, and the
particles are pressed in during the injection molding.
57. A method in accordance with claim 51, wherein the surface of
the molded body is modified at least in certain sections by means
of a molding operation.
58. A method in accordance with claim 57, wherein the molding
operation is carried out by the LIGA process.
59. A ventilator with an air delivery system, to which a patient
interface can be connected by a respiratory gas hose, wherein at
least one area of at least one part of the total device, which
consists of the ventilator, the respiratory gas hose, and the
patient interface, has a surface that has flow-optimized and/or
textured and/or porous properties.
Description
[0001] The invention concerns a ventilator, which has at least one
flow path and comprises several interconnected components, which
are successively arranged along the flow path, which runs through
these components.
[0002] In previously known ventilators, the air path is
characterized by several components with different functions. In
particular, these components are air-intake filters, air lines in
the ventilator, sound absorbers, fans, air line to the patient,
hose, and patient interface (mask, tube, nasal pillow).
[0003] The invention can be used, for example, in the following
types of medical apparatuses: CPAP devices, APAP devices, bilevel
ventilation devices, titration devices, home ventilators, emergency
ventilators, hospital ventilators, suction devices, and other types
of medical apparatuses.
[0004] In the previously known devices, the individual elements of
the air path are optimized for their specific function and are not
necessarily designed for optimum flow guidance. For example, the
sound absorber is designed primarily to minimize sound and not to
allow ideal flow of the respiratory gas. However, the competing
goals can result especially in flow effects that increase the sound
and the power consumption and adversely affect the quality of the
therapy.
[0005] The large number of parameters makes it very difficult to
objectify individual elements. Nevertheless, the use of
fluid-mechanical experiments and numerical control systems makes it
possible to isolate individual parameters and make them accessible
to objective evaluation. Naturally, the optimization of individual
elements will have different effects elsewhere, so that it is
necessary to coordinate the optimization of the individual
elements.
[0006] The objective of the present invention is to lower power
consumption by reducing the total resistance coefficient and to
reduce sound generated by turbulence.
[0007] In accordance with the invention, this objective is achieved
by optimizing the flow resistance of each individual component to
achieve a low resultant total flow resistance of all
components.
[0008] To this end, components that are coordinated with one
another are produced, which do not necessarily have optimized
characteristics with respect to their individual functions, but
rather produce optimized characteristics for a ventilator by the
interaction of all of the components.
[0009] In particular, the following measures serve this
purpose:
[0010] creation of flow-optimized surfaces in the total air path,
for example, similar to a shark's skin,
[0011] coordination of the transitions/interfaces to achieve
idealized flow guidance (no corners and edges), and
[0012] consideration of physical principles to reduce the flow
resistance.
[0013] These measures can be carried out, for example, on the
following components: air-intake filters, air line in the
ventilator, sound absorbers, fans (optimization of blade geometry,
air baffles), air line to the patient, hose, patient interface, and
interfaces between the individual components.
[0014] In a ventilated patient, two systems are connected with each
other--the ventilation system and the lung. The connecting piece
between these two systems is the hose and/or the patient interface
(PI). As a rule, this connecting piece has a smaller diameter than
the part of the system before it and the part after it.
[0015] This diameter dimensioning results in considerable flow
resistance, which manifests itself as a pressure drop and can be
quantified. It is defined as the pressure difference between the
outer, proximal end of the hose and the inner, distal end of the
hose.
[0016] To quantify this resistance, the pressure can be measured at
each end, and then the resistance (.DELTA.P.sub.PI; PI=patient
interface) can be computed from the measured values. P.sub.prox is
the pressure at the proximal end, and P.sub.dis is the pressure at
the distal end. This indicates that a difference is involved. The
formula is:
.DELTA.P.sub.PI=P.sub.prox=P.sub.dis.
[0017] During inspiration, the pressure before the tube is greater
than the pressure after the tube. This results in a positive
.DELTA.P.sub.PI. During expiration, the pressure in the trachea is
greater, and this results in a negative .DELTA.P.sub.PI. This
difference depends on both the inside diameter (ID) of the PI and
the flow (gas flow, F [L/s]).
[0018] The measurements of the pressure drop of different PI's at
different flows yield PI-specific pressure-flow characteristic
curves. The PI-produced pressure loss means additional, ineffective
respiratory work. This additional respiratory work must be
performed by the:
[0019] (a) patient
[0020] (b) ventilator
[0021] (c) ventilator and patient.
[0022] If the patient must take over the work, there is a risk of
early respiratory exhaustion.
[0023] If the ventilator takes over the work, it must perform
additional work during an inspiration, which can result in
increased power consumption, increased sound generation, and
diminished automatic control precision.
[0024] During expiration, the pressure in the PI must be reduced in
such a way that expiration is not hindered and effective
elimination of CO.sub.2 is possible.
[0025] The flow resistance can be reduced by providing the
component with a surface profile.
[0026] In particular, it is proposed that the surface profile have
a lotus structure.
[0027] In another embodiment, the surface profile has a sharkskin
structure.
[0028] If the surface profile has longitudinal grooves, this
contributes to the development of laminar flow.
[0029] To adapt to specifically prevailing flow velocities and
volume flows, it is provided that the longitudinal grooves have
different widths relative to one another.
[0030] In accordance with another design variant, it is also
proposed that the longitudinal grooves be separated from one
another by different distances.
[0031] In one embodiment, the longitudinal grooves are formed as
sawtooth grooves.
[0032] In another embodiment of the invention, the longitudinal
grooves are formed as trapezoidal grooves.
[0033] In another embodiment, the longitudinal grooves are formed
as L-shaped grooves.
[0034] If at least two components have flow paths with a continuous
transition into each other, this helps prevent the development of
turbulence.
[0035] Sound emission can be reduced if the flow path has a porous
trailing edge in the vicinity of at least one cross-sectional
constriction.
[0036] To avoid turbulence, it is also useful if the flow path is
provided-with a flow guide element in the vicinity of at least one
cross-sectional change.
[0037] In a preferred embodiment, the flow guide element is
designed as a brush-shaped edge.
[0038] In accordance with another embodiment, it is also proposed
that the flow guide element be formed as a soft lamella.
[0039] Different advantageous material properties can be combined
by using a porous flow guide element.
[0040] A further objective of the invention is to design a medical
apparatus in such a way that its functionality is improved.
[0041] In accordance with the invention, this objective is achieved
by providing at least one of the components of the apparatus with a
surface coating and/or by providing the surface with functional
properties that include at least optimized flow.
[0042] Another objective of the present invention is to improve a
method of the aforementioned type in such a way that an embodiment
is realized which is functional and at the same time inexpensive
and capable of operating for extended periods of time.
[0043] In accordance with the invention, this objective is achieved
by producing the molded body by plastic injection molding and then
coating at least certain sections of the molded body.
[0044] The use of surface-coated components in medical apparatuses
basically allows much greater design latitude. The functional
properties desired in a given situation can be provided by the
surface coating, independently of the material of the substrate.
The functional properties can be related, for example, to
antifriction properties, friction properties, surface shaping, or
surface hardening.
[0045] The surface coating of the substrate is selected according
to the predetermined functional property, and the base material of
the substrate can be determined independently of the desired
functional property of the surface and the mechanical or static
boundary conditions. For example, it is possible, when high
mechanical stresses are present, to provide a hard substrate with a
softer surface coating or to furnish a soft and elastic substrate
with an antiseptic functional surface. If necessary, the desired
surface coatings are applied to the substrates with the use of
suitable intermediate layers that serve as adhesion promoters.
[0046] In a preferred embodiment, the molded body is basically
formed as an apparatus part, apparatus cover, apparatus internal
part, apparatus accessory part, apparatus component, air
humidifier, nebulizer, medication atomizer, ventilator, air-intake
filter, sound absorber, air path in the apparatus, filter,
ventilator mask, ventilator hose, emergency ventilator, suction
device, suction hose, collecting container of a suction device, or
housing part.
[0047] A molded body of this type for a medical apparatus is
produced at least partly and/or in certain sections from plastic.
In this regard, different plastics are often used. The plastics
perform various functions and must be suited in the best possible
way for the given function to be performed. The plastics used to
make, for example, a ventilator are thus optimized for the specific
purposes of the individual components, i.e., intake
filter--ventilator--output filter--patient hose--filter--patient
contact point.
[0048] All known plastics can be used as the plastics, e.g.,
polyethylenes, polypropylenes, polyvinyl chlorides, polystyrenes,
polycarbonates, cellophanes, cellulose acetates, polyolefins,
fluorocarbon resins (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, vinylides, and
rayon.
[0049] In addition, it is possible to use all polymers that are
suitable for the injection molding of injection-molded parts.
Materials to be used for injection molding are preferably polymers
or polymer blends that contain a polymer based on polycarbonates,
polyoxymethylenes, poly(meth)acrylates, polyamides, polyvinyl
chloride, polyethylenes, polypropylenes, linear or branched
aliphatic polyalkenes, cyclic polyalkenes, polystyrenes,
polyesters, polyethersulfones, polyacrylonitrile or polyalkylene
terephthalates, polyvinylidene fluoride, polyhexafluoropropylene,
polyperfluoropropylene oxide, polyfluoroalkyl acrylate,
polyfluoroalkyl methacrylate, polyvinylperfluoroalkyl ether or
other polymers of perfluoroalkoxy compounds, polyisobutene,
poly(4-methylpentene-1), polynorbornenes as homopolymers or
copolymers or their mixtures. Especially preferred materials to be
used for injection molding are polymers or polymer blends that
contain a polymer based on polyethylene, polypropylene, polymethyl
methacrylates, polystyrenes, polyesters,
acrylonitrile-butadiene-styrene terpolymers (ABS), or
polyvinylidene fluoride, such that the plastics can be used in pure
form and/or as a mixture. Polycarbonates, polyoxymethylenes,
poly(meth)acrylates, polyamides, polyvinyl chloride, polyethylenes,
polypropylenes, linear or branched aliphatic polyalkenes, cyclic
polyalkenes, polystyrenes, polyesters, polyacrylonitrile or
polyalkylene terephthalates, polyvinylidene fluoride, or other
polymers of polyisobutene, poly(4-methylpentene-1), polynorbornenes
as homopolymers or copolymers, a polymer based on polycarbonates,
polyoxymethylenes, poly(meth)acrylates, polyamides, polyvinyl
chloride, polyethylenes, polypropylenes, linear or branched
aliphatic polyalkenes, cyclic polyalkenes, polystyrenes,
polyesters, polyacrylonitrile or polyalkylene terephthalates,
polyvinylidene fluoride, or other polymers of polyisobutene,
poly(4-methylpentene-1), polynorbornenes as homopolymers or
copolymers and their mixtures, and their mixtures.
[0050] In addition to plastics, it is also possible to use metals
and/or ceramic and/or glass, or any desired combinations of these
materials, including combinations with the plastics listed
above.
[0051] In this regard, the surface can be completely or partially
covered with the polymers.
[0052] It is possible merely to melt the polymer on and/or to apply
only such a small amount to the surface that, if desired, a
granular structure of the polymer is maintained. Surface texturing
is achieved in this way.
[0053] In accordance with the invention, it is proposed that the
surfaces be designed to be rough and hydrophobic. In this regard,
it can be a surface with an artificial surface structure consisting
of elevations and depressions and, in addition, with self-cleaning
properties. The surface structures are preferably on the nm to um
scale. It is especially preferred for the surface structures to be
spaced more or less evenly apart.
[0054] In addition, the surface can contain particles that are
fixed on the surface by means of a matrix system.
[0055] In this regard, at least one surface of the molded body is
made of a material which has flow-optimized properties and is
selected from among polymers, such as polyamides, polyurethanes,
polyether block amides, polyester amides, polyvinyl chloride,
polyolefins, polysilicones, polysiloxanes, polymethyl methacrylates
or polyterephthalates, metals, fibers, fabrics, glasses, or
ceramics.
[0056] To this end, the surface structure is produced by applying
and fixing particles on the surface.
[0057] In this connection, it is provided that the particles have a
mean particle diameter of 0.05 to 2,000 nm.
[0058] These particles form an irregular fine structure in the
nanometer range on the surface.
[0059] In a preferred modification of the invention, the molded
bodies have a textured surface with regular and/or irregular
elevations and/or depressions on the nm and/or um scale.
[0060] In this regard, the surface has at least one firmly anchored
layer of microparticles that form elevations. The elevations have a
mean height of 20 nm to 25 .mu.m and are spaced apart a mean
distance of 20 nm to 25 .mu.m. However, a mean height of 50 nm to 4
um and/or a mean spacing distance of 50 nm to 4 .mu.m is
preferred.
[0061] Furthermore, the surface has self-cleaning properties and
elevations formed by microparticles. It is produced by pressing
hydrophobic microparticles into the surface of the surface
extrudate. The microparticles that are used have a mean particle
diameter of 0.02 to 100 .mu.m.
[0062] Textured surfaces with a low surface energy are also part of
the invention.
[0063] Therefore, an object of the present invention is textured
surfaces which have elevations with a mean height of 10 nm to 200
.mu.m and a mean spacing distance of 10 nm to 200 .mu.m and whose
outer shape is described by a mathematical curve and/or function
with symmetry with respect to a plane.
[0064] An especially low surface energy is necessary especially
when not only hydrophobic but also oleophobic behavior is required.
This is the case especially with nonsolid oily contaminants (Lotus
Effect.TM.).
[0065] To produce such a surface, the textured, hydrophobic surface
with elevations and depressions is treated with an additive that
has a particle size of 0.0001 to 20 .mu.m and an organic matrix
that contains at least one thermoplastic, elastomeric, or
thermosetting plastic.
[0066] Preferred microparticles have an irregular fine structure in
the nanometer range on the surface and a particle diameter of 0.02
to 100 .mu.m, preferably 0.1 to 50 .mu.m, and especially 0.1 to 10
.mu.m. However, suitable microparticles can also have a diameter of
less than 500 nm or can be agglomerates or aggregates built up from
primary particles. These agglomerates or aggregates have a size of
0.2 to 100 .mu.m.
[0067] It can be advantageous for the microparticles to have
hydrophobic properties. The hydrophobic properties can be based on
the material properties of the materials themselves, which are
present on the surfaces of the particles, or they can be produced
by treating the particles with a suitable compound. The
microparticles can have been furnished with functional properties
before or after the application to or binding on the surface of the
device or injection-molded part.
[0068] The invention also includes a method for producing plastic
granules and powders.
[0069] If products made of polyolefins are to be lacquered,
printed, coated, or adhesively bonded, it is necessary to pretreat
the molded parts, since printing inks and adhesives do not adhere
sufficiently well to the nonpolar surface of these plastics.
Thermal or wet-chemical methods are customarily used. The desired
oxidation of the surface can also be realized by an electronic-type
plasma treatment.
[0070] A plasma method makes it possible to treat polyolefin
granules and powders, so that a subsequent treatment of the parts
can be eliminated. Very thin nanolayers, e.g., of
polytetrafluoroethylene (PTFE (Teflon)), can be deposited on
various substrates by an HF-CVD process. Different material
surfaces can be provided with the desired functional properties in
this way.
[0071] The chemical sol-gel process, which yields nanomaterials, is
a variant of inorganic synthetic chemistry which until now has
found little use in the development of materials. It uses liquid
starting materials and a low-temperature process to produce
inorganic or inorganic-organic materials with wide ranges of
composition and structure.
[0072] The goal of using ceramics for the nanotexturing of surfaces
is to alter the properties of known materials or to provide known
materials with new functions, e.g., to produce columnar structures
in the range of 20-300 nanometers on metal and plastics by stamping
processes. This causes a change in interfacial properties. The
formation of hemispherical structures with a radius of 250-350 nm
on, for example, glass surfaces, significantly reduces their
reflection of light. This effect is based on the creation of a
continuous transition between the surrounding air and the glass
surface, which can be achieved in this way only by
nanostructures.
[0073] A combination of microtexturing and nanotexturing can be
used simply and easily to alter the surfaces.
[0074] The solvent that contains the particles can be applied to
the polymer surface, e.g., by spraying, by doctoring, by dropping,
or by immersing the polymer surface in the solvent that contains
the particles.
[0075] The method of the invention can be used to produce a polymer
surface with favorable flow properties, which has an artificial, at
least partially hydrophobic surface structure that consists of
elevations and depressions formed by particles fixed on the polymer
surface.
[0076] The particles can also be present in the form of aggregates
or agglomerates. In this regard, according to DIN 53 206,
aggregates are understood to be primary particles joined together
along their surfaces or edges, while agglomerates are understood to
be primary particles with point contact.
[0077] The structures described above can be produced, e.g., by an
injection-molding process in combination with a conventional
injection-molding die produced by the LIGA process. The LIGA
process is a texturing process that is based on basic processes of
x-ray lithography, electroforming, and molding. The process differs
from micromechanics in that the structures are not produced in the
base material by an etching process but rather can be molded
inexpensively by a die. In the present case, the LIGA process is
used to produce the die.
[0078] In addition, undesired changes in the physical properties of
the substrates can be largely eliminated in this way, since only a
very thin coating on the surface of the substrate is changed. The
method of the invention can be readily combined with other methods
of surface finishing treatment. For example, it is possible, after
the thermally assisted application of the polymers, to render the
surface hydrophilic with water and acids.
[0079] The material properties of the various plastics are affected
to only an insignificant extent. Characteristics such as the
continuous use temperature, creep strength, and thermal and
electrical insulation are preserved. The compound can be used under
all conceivable conditions of production, processing, and use. It
is used with semifinished products made of PEEK, PPSU, POM-C, and
PET and with injection-molded parts, extruded sections, and
calendered sheets.
[0080] Alternatively and/or in addition to the aforementioned
properties, the molded bodies of the invention can have the
following properties. It is also contemplated that a molded body of
the invention can have several properties, at least in certain
sections.
[0081] flame-retardant
[0082] low kinetic friction
[0083] flow-optimized
[0084] anticorrosive
[0085] electrochemically active
[0086] low reflection
[0087] electrochromic
[0088] photochromic
[0089] piezoelectric
[0090] conductive
[0091] scratch-resistant
[0092] antireflective
[0093] Alternatively and/or in addition to the aforementioned
method for producing molded bodies of the invention, the following
processes can be used.
[0094] plasma process
[0095] laser process
[0096] sol-gel process
[0097] galvanic processes
[0098] production of nanostructures by self-organization
[0099] nanotexturing of materials and surfaces
[0100] vacuum evaporation (electron-beam evaporation)
[0101] vacuum evaporation (resistance crucible evaporation)
[0102] cathode sputtering
[0103] CVD processes (chemical vapor deposition)
[0104] PVD processes (physical vapor deposition
[0105] LIGA process
[0106] thermal oxidation
[0107] microelectroforming (hard alloy depositions)
[0108] injection molding of plastic microcomponents
[0109] vacuum coating
[0110] chemical electroplating
[0111] in-mold coating
[0112] precoating
[0113] In addition, the invention includes a method for producing
molded bodies of the invention. Advantageous embodiments of the
method of the invention are specified in the dependent claims.
[0114] Specific embodiments of the invention are illustrated in the
accompanying schematic drawings.
[0115] FIG. 1 shows surface shaping with the use of sawtooth
grooves.
[0116] FIG. 2 shows surface shaping with the use of trapezoidal
grooves.
[0117] FIG. 3 shows surface shaping with the use of L-shaped
grooves.
[0118] FIG. 4 shows a block diagram illustrating the basic
functional components of a device for measuring flow
resistance.
[0119] FIG. 5 is a table that summarizes the flow resistance of
various ventilator masks at various volume flows.
[0120] FIG. 6 is a graphic summary of the test results compiled in
the table in FIG. 5.
[0121] FIG. 7 shows an elbow angle that has been optimized for
flow.
[0122] FIG. 8 is a perspective drawing in viewing direction XIII in
FIG. 7.
[0123] FIG. 9 shows a modification of the embodiment illustrated in
FIG. 8.
[0124] FIG. 10 is a schematic drawing illustrating the development
of turbulence in the vicinity of a cross-sectional constriction of
the flow path.
[0125] FIG. 11 shows a modification of the embodiment illustrated
in FIG. 10 with the use of brush-like transition elements.
[0126] FIG. 12 is a schematic drawing illustrating flow guidance in
the vicinity of a cross-sectional expansion with the use of
brush-like flow elements.
[0127] FIG. 13 shows the arrangement according to FIG. 12 without
the use of flow guide elements.
[0128] FIG. 14 shows a graph that summarizes flow resistance as a
function of flow for various embodiments.
[0129] FIG. 15 shows a medical device.
[0130] FIG. 16 is a perspective drawing of a humidifier, which can
be inserted between the ventilator and a ventilation hose.
[0131] FIG. 17 shows a ventilator with an oxygen supply valve for
supplying an increased oxygen concentration.
[0132] FIG. 18 is a perspective drawing of a ventilator mask with a
forehead support.
[0133] FIG. 19 shows a surface profile.
[0134] FIGS. 20-25 show various types of surface topography.
[0135] In the embodiment illustrated in FIG. 1, the surface of a
flow path is shaped to take advantage of the effect that the flow
resistance can be reduced by fine longitudinal grooves in the
surface of bodies over or around which flow is occurring.
Resistance reductions of up to about 10% were measured, compared to
a "smooth surface". Resistance-reducing grooved surfaces (riblets)
are of interest whenever high demands are placed on surface quality
at relatively high flow velocities. This is the case even though
the surface area of the body is significantly increased by the
grooves and even though, according to classical theory, the grooved
surface is a "rough surface". In accordance with the invention, it
is proposed that some portions of the inside wall of the tube be
provided with grooves of varying sizes and configurations.
[0136] Resistance-reducing grooved surfaces (riblets) consist of
microscopically small grooves that are aligned parallel to the
flow. The grooves must be dimensioned in such a way that they act
as a hydraulically smooth surface for the flow. The
resistance-reducing effect consists in hindrance of the turbulent
transverse components of the flow at the wall. The riblet surfaces
of the invention can reduce turbulent wall friction by up to
10%.
[0137] A correlation between flow velocity and groove spacing
exists inasmuch as narrower grooves have a greater probability of
being smaller than the half lateral wavelength and thus generate
smaller turbulence. In accordance with the invention, therefore, it
is proposed that the riblet surfaces have different riblet
dimensions and/or different riblet spacing in the area of the
ventilator, depending on the flow conditions prevailing there.
[0138] Test results show reduced resistance of the grooved film of
5-10% compared to the smooth structure.
[0139] The lowering of resistance by the grooved structure can be
explained by the occurrence of different, textured subregions in
the boundary layer. These boundary layers have an effect on the
turbulence.
[0140] In the laminar lower flow layer, strips of high velocity
alternate with strips of low velocity. These structures affect the
turbulence behavior at the boundary layer. The spaces between the
strips can be calculated as follows:
[0141] W=100 1
[0142] l=v/U.sup.T
[0143] W: groove spacing
[0144] l: characteristic length of the lower layer
[0145] v: kinematic viscosity
[0146] U.sup.T: friction velocity
[0147] The friction velocity is defined as: Reynolds
number=inertial forces/frictional forces. It describes the
hydrodynamic similarity of a body as a function of the viscosity of
the medium surrounding it.
[0148] The invention provides for the use of surfaces with high
Reynolds numbers. The inertia of the medium is constant; high
Reynolds numbers are produced by very low frictional forces near
the surface, which are achieved by the characteristic grooved
structure.
[0149] In summary, it can be said that grooves with smaller spacing
are used in regions of faster flow than in regions of slow flow;
the grooves are aligned with the flow and overlap one another.
[0150] Another aspect of the invention in that the surfaces of the
invention experience hardly any contamination, i.e., a lotus effect
is observed.
[0151] The air resistance can be described by the formula:
W=rho/2.times.cw.times.A.times.V.sup.2.
[0152] If one wishes to achieve faster flow with a certain power,
this can also be accomplished by reducing the cw value and the area
A (the air density rho is predetermined by air pressure and
temperature). While the area can be reduced only to a certain
limit, there is a great deal of potential in the case of the cw
value. The air resistance W can be broken down into a pressure
component and a friction component.
[0153] The pressure drag involves defects of form and the
turbulence resulting from them. If complete pressure equalization
can no longer occur due to burble, a drag arises which is known as
pressure drag. However, it can be reduced to a minimum by perfect
shaping.
[0154] Another objective of the present invention is to make the
shape close to the absolute optimum, so that the "streamlines"
close again with practically no pressure losses / vortices. This
increases the friction component, to which it is therefore
necessary to devote more attention. The frictional resistance
arises from shear stresses between the body and the medium flowing
around it.
[0155] The frictional resistance can be broken down into a laminar
component and a turbulent component. In the front part of the
lining, the flow is initially laminar, but then, depending on the
shape and surface, it becomes turbulent flow at a certain point,
which means a definite increase in resistance in the region which
follows. Consequently, an effort must be made to keep the flow in
the boundary layer laminar for as long as possible. This can be
accomplished by the use of laminar profiles, in which the greatest
width is not reached until at least 50% of the total length, so
that the flow is accelerated for a longer period of time, and
laminar flow can be maintained more easily in this acceleration
interval.
[0156] Another possible means of maintaining laminar flow consists
in optimization of the surface in the front region by, for example,
riblet surfaces. If, on the other hand, the flow is separated at a
certain point by a defect of form, it is possible, by increasing
the roughness in this area, to capture the flow again by this
well-defined energy input and thus reduce the resistance (the
pressure drag).
[0157] Alternatively, the turbulent part of the boundary layer can
be made at least partially laminar by removing "mini-vortices" that
develop through small drill holes in the surface.
[0158] In accordance with the invention, it is also proposed that
numerical fluid mechanics be used to determine wall shear stresses,
coefficients of friction, wall friction, air resistance, and their
contributions to the total resistance.
[0159] FIG. 1 shows a component 1 of a ventilator. The surface 2 of
the component 1 is provided with a surface profile 3. The surface
profile 3 consists of elevations 4 which bound groove-like
depressions 5.
[0160] The specific embodiment according to FIG. 1 shows a pattern
of the surface profile 3 with sawtooth grooves that extend in the
longitudinal direction of flow. The elevations 4 and the
depressions 5 each form angles of about 60.degree.. The width of
the elevations 4 and the width of the depressions 5 are selected to
be basically equal.
[0161] FIG. 2 shows an embodiment of the surface profile 3 in the
form of trapezoidal grooves. The elevations 4 are formed
essentially the same as in FIG. 1, but they have a narrower apex
angle of about 45.degree.. The distance (S) between the peaks of
two elevations is about twice the height (S/2) of the elevations
4.
[0162] FIG. 3 shows an embodiment in which the surface profile 1
consists of L-shaped grooves. Fin-like projections rise above the
surface 2. The distance (S) between the fins is about twice the
height (S/2) of the fins.
[0163] FIG. 4 shows a basic design for a device for measuring flow
resistance. A flow source 6 is connected to a flowmeter 7. A valve
8 is located after the flowmeter 7. A pressure gage 9 is connected
to a line connecting the flowmeter 7 and the valve 8.
[0164] Measurement results obtained with the use of the measuring
device shown in FIG. 4 are tabulated in FIG. 5. The flow resistance
was determined for eight ventilator masks, which were used as
examples of different patient interfaces. The total flow resistance
of the individual masks was determined. Test objects 1 to 6 are
state-of-the-art masks, and test objects 7 and 8 were optimized
with respect to their flow guidance in accordance with the
invention. In particular, the following test objects were tested
with the test setup according to FIG. 4:
TABLE-US-00001 Test Object 1: ResMed; Mirage (from current
production) Test Object 2: ResMed; Ultra Mirage (from current
production) Test Object 3: Respironics; Comfort Select (from
current production) Test Object 4: MAP; Papillon (from current
production) Test Object 5: Weinmann; SOMNO mask (from current
production) Test Object 6: Weinmann; SOMNO plus (from current
production) Test Object 7: Weinmann; vented (prototype close to
production) Test Object 8: Weinmann; nonvented (prototype close to
production)
[0165] The testing device used as the flowmeter was the Timeter
PM-No. 107-015. The SI PM No. 205-029 was used as the pressure
gage. In addition, a device was used, the Weinmann SOMNOcomfort
model, which was modified to allow a constant speed to be set. The
test setup illustrated in FIG. 4 is explained in greater detail
below.
[0166] The flow resistance of the test objects was measured for
volume flows of 50 L/min and 100 L/min. The measure of the flow
resistance is the level of the dynamic pressure in front of the
test object compared to the ambient pressure. The dynamic pressure
is conducted to the pressure gage, where it is measured, through a
thin hose, which is connected in front of the test object in the
flow channel. The two volume flow values (50 L/min and 100 L/min)
were produced by a modified SOMNOcomfort, whose speed can be set to
a constant value, and checked by the Timeter. All of the intended
openings (discharge openings) and unintended openings (interfaces,
e.g., between elbow and turn sleeve) were sealed before the start
of the measurement.
[0167] FIG. 6 summarizes the test results according to FIG. 5 for
the volume flows of 50 and 100 L/min. The values plotted for the
individual test objects correspond to the values in FIG. 5.
Especially in the case of test object No. 7, it is apparent that
the flow resistance could be halved by the design of the invention
compared to the best state-of-the-art comparison device.
[0168] In addition to the surface shaping in accordance with the
invention, the flow guidance is also quite important. Especially in
the case of a patient interface in the form of a mask, an angled
connector is often used for connection to the ventilator hose. The
geometry of the angle and of the hose connection is a significant
factor affecting the resulting flow resistance. With respect to the
reduction of the flow resistance, a connection angle
of<70.degree. and a connection diameter of>18 mm have been
found to be especially advantageous. Furthermore, the automatic
control precision can be increased, and energy savings can be
achieved.
[0169] FIG. 7 shows an angled connector 10 with a ball-and-socket
joint 11 for connection to a ventilator mask (not shown). The elbow
angle is about 70.degree..
[0170] FIG. 8 shows the connector 10 according to FIG. 7 in viewing
direction VIII in FIG. 7. The diameter at the narrowest point is
about 15.2 mm.
[0171] FIG. 9 illustrates that the connector has an area of about
210 mm.sup.2 at its narrowest point.
[0172] The importance of fluid-mechanical shape optimization
decreases nonlinearly with flow velocity. However, it is precisely
in the range of high ventilation pressures and high flows that a
fluid-mechanically favorable shape has an especially strong effect
on energy savings, sound reduction, and the quality of therapy.
[0173] Additional tests were aimed at reducing the sound-emitting
effect of edges over which flow is occurring. Sound arises at edges
over which flow is occurring by conversion of some of the turbulent
wall pressure fluctuations to propagable pressure waves. Since this
process is causally related to the nonuniform change in the
boundary conditions at the edge, a change of the edge
characteristics towards a more uniform transition from the hard
wall into the free flow was also seen here as a potential solution
to the problem of noise reduction.
[0174] FIG. 10 shows a flow path 12 with a principal direction of
flow 13. In the principal direction of flow 13, the respiratory gas
flow first passes through a first cross-sectional area 14 and then
through a second cross-sectional area 15. The first cross-sectional
area 14 makes the transition to the relatively smaller second
transition area 15 by means of a step-like constriction 16. FIG. 10
shows the turbulence 17 produced by the constriction 16 at this
type of transition.
[0175] In FIG. 11, flow guide elements 18 are used to prevent
turbulence 17. The practical realization of the flow guide elements
18 takes the form of a set of brushes aligned in the principal
direction of flow 13 on the upper edge. A noise reduction of 2 to 3
dB was achieved. Noise reduction is observed chiefly at low
frequencies.
[0176] The geometry of the flow guide elements 18 can be varied to
adapt to the specific application specifications. In particular,
the thickness, the density, the length, and the flexibility can be
varied. In particular, a flexible design of the flow guide elements
18 has been found to be important.
[0177] In accordance with another embodiment, it is also proposed
that flow-optimized trailing edges 19 be used alternatively or
additionally to the flow guide element 18. Especially trailing
edges 19 made of a porous material have been found to be
advantageous. It is also possible to make the flow guide elements
18 from a porous or open-pored material. Ideally, this is done in
combination with a flexible design of the flow guide elements 18.
The use of the flow guide elements 18 resulted in experimental
noise reduction of up to 12 dB.
[0178] Another area of application for optimization of the flow
guidance is related to the generation of the respiratory gas and
the components used for this purpose. The rotor of the fan is the
most important source of sound, and the sound is strongly dependent
on the clearance of the rotor perimeter. By systematic reduction of
the clearance (up to 85% of the initial state), it was possible to
achieve considerable noise reduction, which is due to a great
extent to the reduction of the flow-off speed at the trailing edge
that is associated with the clearance reduction.
[0179] The flow-off noises at the terminal and lateral edges and
the transitions can be considerably reduced by suitable edge design
(e.g., brushes, porous terminal edges).
[0180] FIG. 12 shows the use of flow guide elements 18 in the
transition zone from a first cross-sectional area 14 to a second
cross-sectional area 15, which is larger than the first
cross-sectional area 14. The first cross-sectional area 14 makes a
transition to the second cross-sectional area 15 by a shoulder-like
expansion 20. The flow guide elements 18 extend out from an edge 21
of the first cross-sectional area 14 into the flow zone of the
second cross-sectional area 15.
[0181] FIG. 13 shows the arrangement according to FIG. 12 without
the use of flow guide elements 18. This results in turbulence
17.
[0182] The measurements of the pressure drop of variously optimized
ventilators at varied flow yield specific pressure-flow
characteristic curves. FIG. 14 shows pressure-flow characteristic
curves for different ventilators. The horizontal scale shows the
flow (flow rate) in liters/second, and the vertical scale shows the
pressure drop APPI in mbars. During inspiration, a positive flow
and a positive pressure difference are present, and during
expiration, a negative flow and a negative pressure difference
prevail.
[0183] FIG. 14 shows that the pressure difference does not change
sharply at a flow between 0 and 25 L/min, but then increases
rapidly with further increases in the flow rate. This can be
explained by the fact that the air shows laminar flow at low flow
rates up to 20 L/min, but turbulence develops at higher flow rates,
and this increases the resistance. The flow varies with each phase
of a breath. At moderate ventilation, the pressure drop is 0-10
mbars.
[0184] The different lines in FIG. 14 represent the pressure-flow
characteristic curves for differently optimized ventilators.
[0185] a--standard
[0186] b--brushes
[0187] c--sharkskin
[0188] d--geometry of the PI-hose connector
[0189] e--brushes+shark skin+geometry of the PI-hose connector
[0190] The pressure drop means additional, ineffective respiratory
work. This additional respiratory work must be performed by
the:
[0191] (a) patient,
[0192] (b) ventilator, or
[0193] (c) ventilator and patient.
[0194] If the patient must take over the work, there is a risk of
early respiratory exhaustion. If the ventilator takes over the
work, it must perform additional work during an inspiration, which
can result in increased power consumption, increased sound
generation, and diminished automatic control precision. During
expiration, the pressure in the PI must be reduced in such a way
that expiration is not hindered and effective elimination of
CO.sub.2 is possible.
[0195] FIG. 15 shows the basic design of a ventilator. A
respiratory gas pump is installed inside a ventilator housing 22,
which has an operating panel 23 and a display 24. A connecting line
26 in the form of a hose is attached by a coupling 25. An
additional pressure-measuring hose 27, which can be connected with
the ventilator housing 22 by a pressure input connection 28, can
run along the connecting hose 26. To allow data transmission, the
ventilator housing 22 has an interface 29.
[0196] An expiratory device 30 is installed in an expanded area of
the connecting hose 26 that faces away from the ventilator housing
22. An expiratory valve can also be used.
[0197] FIG. 15 also shows a ventilation mask 31, which is designed
as a nasal mask. The mask can be fastened on the patient's head by
a head fastening device 32. A coupling device 33 is provided in the
expanded region of the ventilation mask 31 that faces the
connecting hose 26.
[0198] The surface coatings can be produced by various methods,
which have already been partly explained above in connection with
examples. The surface coatings can be produced by introducing
particles, as described above, but it is also possible to use vapor
deposition techniques, lamination techniques, or plasma coating
techniques. It is likewise possible to use the aforementioned
methods for applying liquid coatings in pure form or diluted with
solvents. Surface treatments, for example, those involving the use
of mechanical means, laser beams, or electron beams, are also
possible.
[0199] FIG. 19 shows a section of a surface profile of a modified
molded body for a medical apparatus with elevations of various
shapes, which have heights of 0.1 nm to 5,000 nm relative to the
base. The distance between the individual elevations is likewise in
the range of 0.1 to 5,000 nm.
[0200] These elevations are arranged in various forms on the
surface to form regular structures. In one embodiment, the
invention comprises, for example, the following accessory parts
that can be used for ventilation applications:
[0201] Humidifier (FIG. 16), 02 valve (FIG. 17), head fastening
device, patient interface (for example, mask, nasal pillows, tube),
hose, filter, mounting, coupling, heater, interchangeable parts,
pocket. It will now be explained how the invention contributes to
improvement of the specified accessory parts.
[0202] Ventilators produce an air volume flow of up to 400 L per
minute. The dimensions of a ventilator, the patient hose, and the
patient interface are basically fixed within narrow limits.
Therefore, the amount of power consumed in producing the air flow
increases at a disproportionately high rate with increasing
velocity of flow. At the same time, the generation of noise
increases with increasing velocity of flow.
[0203] The reduction of noise generation, measured at a distance of
1 meter, can typically amount to at least 5% or at least 1 dB(A).
In regard to the reduction of power consumption, it is intended
especially that the reduction should be at least 2%. In another
variant, the amount of time needed for a necessary cleaning should
be reduced by at least 10%.
[0204] Therefore, in accordance with the invention, it is proposed
that the frictional forces of the surfaces be reduced in order to
save energy and/or limit noise generation. The resistance-reducing
surfaces of the invention consist of microscopically small surface
structures, for example, grooves, which are preferably aligned
parallel to the direction of flow of the medium. Surfaces of this
type are known in the natural world, for example, shark's skin. The
surface structures are dimensioned in such a way that they act as a
hydraulically smooth surface for the flowing medium. The
resistance-reducing effect consists in hindrance of the turbulent
components of the flow.
[0205] The surface structures are preferably spaced essentially
equal distances apart. These essentially equal distances are in the
range of 100 nm to 200 .mu.m, and preferably in the range of 5
.mu.m to 100 .mu.m. It is especially preferred for the surfaces of
the invention to have reduced resistance on the order
of>1.0%.
[0206] In accordance with the invention, the air-conveying part of
a ventilator and/or hose has, at least in certain sections, a
textured surface with regular and/or irregular elevations and/or
has a surface that reduces the friction of a flowing medium and/or
has a flow-optimized surface.
[0207] To prevent the respiratory passages from becoming dry, the
respiratory air is typically humidified. Since patients perceive
warmed air to be pleasant, and since the air can hold more water
vapor when it is heated, for example, by a heating element 35, a
water supply tank that is used as a liquid reservoir 36 of the
humidification system is typically heated indirectly and/or
directly, for example, by the metallic base of the water supply
tank or, for example, by means of an immersion heating element 35.
A respiratory gas humidifier can be externally connected to a
ventilator on the outside by a coupling 25 and/or it can be
installed inside a ventilator. Due to hygienic requirements that
must be met, it must be possible to remove the humidifier for
cleaning and nevertheless to guarantee a sufficient seal from the
water. The humidifier consists of an upper part 38, which serves
essentially for conveying the air and also for connecting the
ventilator 22 and the connecting hose 26, and a lower part 39 that
holds the water supply. The upper part 38 has a liquid filling hole
40 with a closure 41.
[0208] A gas line 42, which is preferably designed as a pressure
measurement line and/or oxygen supply line, can be arranged in the
vicinity of the humidifier. The gas line 42 is connected with the
humidifier by a gas coupling 43. The humidifier can be coupled with
a connecting hose 26 by a connecting adapter 44. Communication with
the ventilator 22 can be realized by a plug connector 45 between
the humidifier and the ventilator. A display 46 can be positioned
near the humidifier.
[0209] FIG. 17 is a perspective drawing of a ventilator 22 with a
coupling 25 and an operating panel 23. A connecting hose 26 is
connected by means of the coupling 25, and a pressure measurement
line 27 passes through the connecting hose 26.
[0210] An oxygen line 49 is mounted on the outside of the
connecting hose 26 and is connected with an oxygen supply valve 47.
The supply valve 47 is connected to an oxygen source (not shown) by
a supply line 50. A control line 51 connects the supply valve 47
with an interface 29 of the ventilator 22.
[0211] In the embodiment illustrated in FIG. 17, the supply valve
47 is mounted on the outside of the ventilator 22. However, it is
also possible to integrate the supply valve in the ventilator.
[0212] The oxygen supply valve preferably has a self-cleaning
and/or hydrophilic and/or oleophobic and/or low-friction and/or
conducting surface.
[0213] A patient interface will now be explained as the next
example of an application. In the embodiment illustrated in FIG.
18, a patient interface is designed as a face mask 31. A mask is
usually designed as a modular system and typically consists of the
following components, which do not constitute a complete
enumeration:
[0214] Body 52 of the mask and/or protruding edge 53 of the mask
and/or expiratory system 54 and/or coupling element 33 and/or joint
55 and/or forehead support 56 and/or forehead support mount 57
and/or forehead pad 58 and/or fastening device 62 for a head
harness, securing ring, and/or release cord. The mask does not
necessarily have to have all of the individual components for it to
be functional.
[0215] The protruding edge 53 of the mask rests against the
patient's face and provides the necessary seal. The body of the
mask is connected with a coupling element 33 by means of a joint. A
forehead support 57 with a forehead pad 58 is used to ensure
reliable positioning of the ventilator mask on the patient's head.
The forehead support is connected with the body of the mask by a
mount 53.
[0216] Various other patient interfaces can be used as alternatives
to a mask. The following are named as examples: nasal pillows,
tubes, tracheostoma, catheter.
[0217] Hereinafter, masks and all mask components, as well as other
patient interfaces, such as nasal pillows, will be combined under
the term patient interfaces.
[0218] At least certain sections of the patient interfaces
preferably have an antiseptic and/or self-cleaning and/or
hydrophobic and/or oleophobic and/or photocatalytic and/or
scratch-resistant and/or nonfogging and/or nonirritating to the
skin and/or low-friction and/or electrically conducting
surface.
[0219] It is especially preferred that the area near the end of the
patient interface that faces the air flow be furnished with
suitable smooth plastics and/or lacquered surfaces and/or coated
plastics and/or surfaces with texturing on the nanometer to
micrometer scale in such a way that reduced friction can be
realized.
[0220] The invention can also be used together with a filter.
Especially in ventilators but also in other types of medical
apparatus, filters are used, mainly in the air intake area, to
retain particulate matter, dust particles, and microorganisms. The
filters are intended to prevent contamination of the apparatus and
contamination of the patient. Alternatively and/or additionally,
filters are used in the area between the apparatus and the patient
or user, especially to avoid hygienic contamination. The filters
usually take the form of replaceable plug-in filters. So-called
combination filters are also used, which can be designed, for
example, as coarse filters and fine filters. If a filter is not
regularly cleaned and/or replaced, retained particulate matter,
dust particles, and microorganisms can increase the flow resistance
of the filter, which causes the efficiency of the apparatus to
decrease or contaminants to be carried to the patient.
State-of-the-art filters must be frequently replaced, which is
time-consuming and expensive.
[0221] In accordance with the invention, it is proposed that the
filters be provided with functional surfaces. This increases the
service life of the filters and thus lowers costs.
[0222] It is preferred that the area near the end of the filter
that faces the air flow be furnished with suitable smooth plastics
and/or lacquered surfaces and/or coated plastics and/or surfaces
with texturing on the nanometer to micrometer scale in such a way
that reduced friction can be realized. It is also preferred to
finish HME filters (heat and moisture exchange filters) in such a
way that they have reduced frictional resistance and/or that they
are antiseptic and/or self-cleaning and/or oleophobic and/or
photocatalytic.
[0223] Functional surfaces have also been found to be effective for
hoses. Especially in ventilators but also in other types of medical
apparatus, such as suction devices, hoses are used to convey a
medium, especially in the area of a connection between the
user/patient and the device. The hoses usually take the form of
replaceable plug-in hoses. If a hose is not regularly cleaned
and/or replaced, retained particulate matter, dust particles,
contaminants, and microorganisms can increase the flow resistance,
which causes the efficiency of the apparatus to decrease or
contaminants to be carried to the patient. State-of-the-art hoses
must be frequently cleaned and/or replaced, which is time-consuming
and expensive. Cleaning must be performed frequently and thoroughly
to eliminate contamination effectively.
[0224] In accordance with the invention, it is proposed that the
hoses be provided with functional surfaces. This increases the
service life of the hoses and at the same time reduces the amount
of time needed to clean them, thereby reducing costs.
[0225] It is preferred that the area near the end of the hose that
faces the air flow/medium flow be furnished with suitable smooth
plastics and/or lacquered surfaces and/or coated plastics and/or
surfaces with texturing on the nanometer to micrometer scale in
such a way that reduced friction can be realized. It is also
preferred that hoses have an electrically conducting surface.
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