U.S. patent application number 14/965943 was filed with the patent office on 2016-04-21 for breathing mask and a sealing lip device for a breathing mask.
The applicant listed for this patent is ResMed R&D Germany GmbH. Invention is credited to Theodor LAUBOECK, Paris MELIDIS.
Application Number | 20160106942 14/965943 |
Document ID | / |
Family ID | 8163856 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160106942 |
Kind Code |
A1 |
MELIDIS; Paris ; et
al. |
April 21, 2016 |
BREATHING MASK AND A SEALING LIP DEVICE FOR A BREATHING MASK
Abstract
An elastomeric cushion for a breathing mask is configured for
sealed delivery of a flow of breathable gas at a positive pressure
with respect to ambient air pressure to an entrance of a patient's
airways including at least an entrance of the patient's nares. The
elastomeric cushion includes a sealing lip with an elastomeric wall
configured to form a seal with the patient's face. An elastomeric
wall thickness of the sealing lip is varied so that when the
sealing lip sealingly engages the patient's face, a portion of the
seal at the patient's nose bridge is formed by a relatively
thin-walled portion of the sealing lip and other portions of the
seal are formed by relatively thick portions of the sealing
lip.
Inventors: |
MELIDIS; Paris; (Olching,
DE) ; LAUBOECK; Theodor; (Hohenbrunn, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ResMed R&D Germany GmbH |
Martinsried |
|
DE |
|
|
Family ID: |
8163856 |
Appl. No.: |
14/965943 |
Filed: |
December 11, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14566115 |
Dec 10, 2014 |
9242062 |
|
|
14965943 |
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12320484 |
Jan 27, 2009 |
8931484 |
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14566115 |
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10220018 |
Jan 30, 2003 |
7827990 |
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PCT/EP2000/001586 |
Feb 25, 2000 |
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12320484 |
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Current U.S.
Class: |
128/205.25 |
Current CPC
Class: |
A61M 16/06 20130101;
A61M 2210/0618 20130101; A61M 16/0683 20130101; A61M 16/0611
20140204; A61M 16/0616 20140204; A61M 2016/0661 20130101; A61M
16/0605 20140204; B29C 45/1676 20130101; A61M 2205/0216 20130101;
B29L 2031/4835 20130101 |
International
Class: |
A61M 16/06 20060101
A61M016/06; A61M 16/08 20060101 A61M016/08; A61M 16/00 20060101
A61M016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2000 |
EP |
PCT/EP2000/001586 |
Claims
1. An elastomeric cushion for a breathing mask configured for
sealed delivery of a flow of breathable gas at a positive pressure
with respect to ambient air pressure to an entrance of a patient's
airways including at least an entrance of the patient's nares, the
elastomeric cushion having zones of differing load-bearing
capability, wherein a first zone includes a zenith of the cushion,
a second zone is positioned opposite the first zone and a pair of
intermediate zones extend between the first and second zones, the
elastomeric cushion comprising: a peripherally extending shell
engaging portion configured to secure the elastomeric cushion to a
shell of the breathing mask; a peripheral wall extending from the
shell engaging portion and defining a plenum chamber, a portion of
the peripheral wall in the first zone being more collapsible that
portions of the peripheral wall in the second zone and the
intermediate zones so that the cushion is pivotable around an axis
that is between the first zone and the second zone and extends
through the pair of intermediate zones; and an engagement surface
defining an opening to the breathing chamber and being configured
to engage the patient's face, the peripheral wall extending from
the shell engaging portion to the engagement surface, wherein
portions of the engagement surface in the first zone and the second
zone have a relatively thin elastomeric wall compared to
elastomeric walls of the portions of the elastomeric surface in the
pair of intermediate zones.
2. The elastomeric cushion of claim 1, wherein the portion of the
engagement surface in the first zone is configured to engage a
bridge of the patient's nose.
3. The elastomeric cushion of claim 1, wherein the shell engaging
portion is configured to be secured to the shell of the breathing
mask by way of a projection and groove system, the projection and
groove system comprising a plurality of projections interlocking
with a plurality of receiving grooves around a periphery of the
shell and a periphery of the cushion.
4. The elastomeric cushion of claim 1, wherein the portion of the
peripheral wall in the first zone comprises a bellows
structure.
5. The elastomeric cushion of claim 1, wherein the portion of the
engagement surface in the second zone is configured to engage the
patient's upper lip or a region between the patient's nose and
upper lip.
6. The elastomeric cushion of claim 1, wherein a cross-section of
the elastomeric walls of the peripheral wall taken along a line
from the shell engaging portion to the engagement surface has a
varied thickness.
7. The elastomeric cushion of claim 1, wherein the portion of the
engagement surface in the first zone is configured to engage a
bridge of the patient's nose, wherein the shell engaging portion is
configured to be secured to the shell of the breathing mask by way
of a projection and groove system, the projection and groove system
comprising a plurality of projections interlocking with a plurality
of receiving grooves around a periphery of the shell and a
periphery of the cushion, wherein the portion of the peripheral
wall in the first zone comprises a bellows structure, wherein the
portion of the engagement surface in the second zone is configured
to engage the patient's upper lip or a region between the patient's
nose and upper lip, and wherein a cross-section of the elastomeric
walls of the peripheral wall taken along a line from the shell
engaging portion to the engagement surface has a varied
thickness.
8. A patient interface for sealed delivery of a flow of breathable
gas at a positive pressure with respect to ambient air pressure to
an entrance to the patient's airways including at least an entrance
of a patient's nares, said patient interface comprising: the
elastomeric cushion of claim 1; the patient interface shell
configured to be secured to the shell engaging portion of the
elastomeric cushion, the patient interface comprising a central
aperture adapted to receive the flow of breathable gas; and
headgear configured to support the patient interface on the
patient's head and maintain the elastomeric cushion in sealing
contact with an area surrounding an entrance to the patient's
airways while maintaining a therapeutic pressure at the entrance to
the patient's airways.
9. The patient interface of claim 8, wherein the plenum chamber is
defined by the patient interface shell in conjunction with the
peripheral wall of the elastomeric cushion, and the plenum chamber
is pressurized at a pressure above ambient pressure.
10. The patient interface of claim 8, further comprising a gas
washout vent located on the patient interface shell, and wherein
the patient interface shell is comprised of a hard and transparent
material.
11. An elastomeric cushion for a breathing mask configured for
sealed delivery of a flow of breathable gas at a positive pressure
with respect to ambient air pressure to an entrance of a patient's
airways including at least an entrance of the patient's nares, the
elastomeric cushion being configured to form a seal with the
patient's face and comprising: a first zone comprising a portion of
an elastomeric wall configured to sealingly engage a bridge of the
patient's nose; a second zone comprising a second portion of the
elastomeric wall configured to sealingly engage the patient's face
at a location opposite the first zone; and a pair of intermediate
zones comprising portions of the elastomeric wall configured to
sealingly engage the patient's face between the first and second
zones, wherein the portions of the elastomeric wall in the first
zone, the second zone and the pair of intermediate zones are
configured so that portions of the seal in the first and second
zone are formed by relatively thin elastomeric walls and portions
of the seal in the pair of intermediate zones are formed by
relatively thick elastomeric walls.
12. The elastomeric cushion of claim 11, wherein the relatively
thick portions of the elastomeric wall in the pair of intermediate
zones has a higher load bearing capability than the relatively thin
portions of the elastomeric wall in the first and second zones.
13. The elastomeric cushion of claim 11 further comprising a
bellows structure overlapping the first zone and configured to
increase a degree of flexibility of the portion of the elastomeric
wall in the first zone.
14. The elastomeric cushion of claim 13, wherein the bellows
structure overlaps portions of the intermediate zones.
15. The elastomeric cushion of claim 11, wherein the first zone,
the second zone and the pair of intermediate zones together define
an opening in the elastomeric cushion.
16. A patient interface for sealed delivery of a flow of breathable
gas at a positive pressure with respect to ambient air pressure to
an entrance to the patient's airways including at least an entrance
of a patient's nares, said patient interface comprising: a patient
interface shell with a central aperture adapted to receive the flow
of breathable gas; the elastomeric cushion of claim 11; and a
plenum chamber defined by the elastomeric cushion and the patient
interface shell, the plenum chamber being pressurized at a pressure
above ambient pressure.
17. The patient interface of claim 16, wherein the elastomeric
cushion and the patient interface shell are secured together by a
projection and groove system, the projection and groove system
comprising a plurality of projections interlocking with a plurality
of receiving grooves around a periphery of the shell and a
periphery of the cushion.
18. The patient interface of claim 17 further comprising headgear
configured to support the patient interface on the patient's head
and maintain the elastomeric cushion in sealing contact with an
area surrounding an entrance to the patient's airways while
maintaining a therapeutic pressure at the entrance to the patient's
airways.
19. The patient interface of claim 18, further comprising a gas
washout vent located on the patient interface shell.
20. The patient interface of claim 19, wherein the shell is
comprised of a hard and transparent material.
21. An elastomeric cushion for a breathing mask configured for
sealed delivery of a flow of breathable gas at a positive pressure
with respect to ambient air pressure to an entrance of a patient's
airways including at least an entrance of the patient's nares, the
elastomeric cushion comprising: a sealing lip with an elastomeric
wall configured to form a seal with the patient's face, an
elastomeric wall thickness of the sealing lip being varied so that
when the sealing lip sealingly engages the patient's face, a
portion of the seal at the patient's nose bridge is formed by a
relatively thin-walled portion of the sealing lip and other
portions of the seal are formed by relatively thick portions of the
sealing lip.
22. The elastomeric cushion of claim 21 further comprising: a
peripherally extending shell engaging portion configured to secure
the elastomeric cushion to a shell of the breathing mask; and an
intervening portion between the shell engaging portion and the
sealing lip, the intervening portion comprising a bellows structure
configured to increase a degree of flexibility of a nasal bridge
engaging portion of the elastomeric cushion.
23. The elastomeric cushion of claim 22, wherein the bellows
structure is positioned between a nose bridge engaging portion of
the sealing lip and the shell engaging portion.
24. The elastomeric cushion of claim 23, wherein a portion of the
bellows structure extends beyond the nose bridge engaging portion
of the sealing lip.
25. The elastomeric cushion of claim 24, wherein an elastomeric
wall thickness of the nasal bridge engaging portion of the
elastomeric cushion varies from the shell engaging portion to the
sealing lip to form an elastomeric thin-wall portion adjacent a
hinge of the bellows structure that promotes a hinged motion around
the hinge.
26. A patient interface for sealed delivery of a flow of breathable
gas at a positive pressure with respect to ambient air pressure to
an entrance to the patient's airways including at least an entrance
of a patient's nares, said patient interface comprising: a patient
interface shell with a central aperture adapted to receive the flow
of breathable gas; the elastomeric cushion of claim 21; and a
plenum chamber defined by the elastomeric cushion and the patient
interface shell, the plenum chamber being pressurized at a pressure
above ambient pressure.
27. The patient interface of claim 26 further comprising headgear
configured to support the patient interface on the patient's head
and maintain the elastomeric cushion in sealing contact with an
area surrounding an entrance to the patient's airways while
maintaining a therapeutic pressure at the entrance to the patient's
airways.
28. The patient interface of claim 27, further comprising a gas
washout vent located on the shell.
29. The patient interface of claim 28, wherein the shell is
comprised of a hard and transparent material.
30. The elastomeric cushion of claim 22, wherein a cross-section of
elastomeric walls of the peripheral wall taken along a line from
the shell engaging portion to sealing lip has a varied thickness.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/566,115, filed Dec. 10, 2014, now allowed, which is a
continuation of U.S. application Ser. No. 12/320,484 filed Jan. 27,
2009, now U.S. Pat. No. 8,931,484, which is a continuation of U.S.
application Ser. No. 10/220,018, filed Aug. 26, 2002, now U.S. Pat.
No. 7,827,990, which is the U.S. National Phase of International
Application PCT/EP00/01586, filed Feb. 25, 2000, which designated
the U.S. and that International Application was not published under
PCT Article 21(2) in English, the entire contents of each of which
are incorporated herein by reference.
BACKGROUND AND SUMMARY
[0002] The invention concerns a sealing lip device for a breathing
mask, a breathing mask per se and a method and a mold for producing
same.
[0003] In particular the invention concerns breathing masks which
can be fitted to the nose region in sealing relationship and which
have a sealing device extending in the region of the upper lip of
the mask wearer between the mouth and the nose. Breathing masks are
used in particular in the medical and technical areas for the feed
of a respiratory gas, in particular under an increased
pressure.
[0004] In those breathing masks, a seal in relation to the surface
of the face of a wearer is usually achieved by a peripherally
extending sealing lip made from an elastomeric material.
[0005] The sealing action achieved with a sealing lip of that kind
generally increases with the pressure with which the sealing lip is
pressed against the surface of the face. However the level of
wearing comfort is adversely affected by comparatively high contact
pressures. Depending on the respective sensitivity of the mask
wearer long-term use of the known breathing masks gives rise to
troubles.
[0006] The object of the present invention is to provide a
breathing mask in which a high level of sealing action can be
reliably achieved, with a high degree of wearing comfort.
[0007] In accordance with the invention that object is attained by
a sealing lip device for a breathing mask having a receiving
opening for receiving at least the nose tip region of a mask
wearer, a sealing lip which is formed from an elastomeric material
and which surrounds the receiving opening and which crosses the
bridge of the nose in the application position and which has a
contact zone provided for bearing against the face of a mask
wearer, wherein the sealing lip is elastically yieldingly arranged
in such a way that in the region of the bridge of the nose there is
a higher degree of flexibility than in the region of the nostrils
and/or the upper lip.
[0008] That advantageously affords a high degree of compatibility
with the most widely varying facial architectures, with a high
level of wearing comfort. The breathing mask according to the
invention is distinguished in particular in the region of the
bridge of the nose by a high degree of sealing integrity, without
considerable pressures in relation to surface area occurring in
that respect. The high level of sealing effect achieved in the
region of the bridge of the nose effectively obviates in particular
eye irritation effects and feeling the effects of drafts.
[0009] In accordance with a particularly preferred embodiment of
the invention the defined flexibility of the sealing lip zone which
fits on the region of the bridge of the nose is achieved by the
sealing lip device being suspended in the region of that zone on a
bellow structure. That bellows structure is preferably dimensioned
in such a way that it forms an abutment device, upon suitably deep
penetration of the bridge of the nose. The abutment surfaces which
come into effect there are preferably such that they form a
comparatively large contact area, at the latest in the inwardly
resiliently deflected condition, so that even when the bellows
structure becomes operative in the resiliently inwardly deflected
condition, the arrangement does not involve any unacceptably high
pressures in relation to surface area.
[0010] In a particularly advantage fashion, a hinge characteristic
which is defined by different wall thicknesses is imparted to the
bellows structure. Preferably the bend or hinge location is of a
comparatively thin-gauge nature, whereas the zones which are
disposed therebetween are slightly thicker. As an alternative
thereto or also in combination with that measure, it is also
possible to provide rolling bellows structures, by virtue of
suitable wall thicknesses.
[0011] In a particularly advantageous manner the bellows structure
has a plurality of fold indentations. Preferably at least one fold
indentation extends from the region of the bridge of the nose into
a region adjacent to the nostrils in the position of use of the
mask.
[0012] Particularly when the structure has a plurality of fold
indentations preferably at least one thereof extends around the
entire periphery of the sealing lip device. The spring
characteristic of the respective fold indentation can be definedly
established for given peripheral zones in such a way that there is
a higher level of flexibility in the region of the bridge of the
nose and there is a lower level of flexibility in the region of the
upper lip or in particular in the region of the nostrils. (Those
orientations are with reference to the application position of the
mask).
[0013] Particularly when using the bellows structure in the sealing
zone region of the bridge of the nose, the sealing device is
preferably designed in such a way that the flexibility of the
sealing lip, which is in opposite relationship to the application
direction, is so matched that there is an adaptation or
articulation axis in the nostril or upper lip region. That makes it
possible for the corresponding breathing mask to be fitted to the
face of the mask wearer predominantly in the region of the zones of
the face which are adjacent to the nostrils and on the upper lip,
in which respect the preferably extremely thin-wall sealing lip
zone which is provided for sealing at the bridge of the nose can be
pivoted with respect to the mask frame, in accordance with the
facial architecture. By virtue of the internal pressure obtaining
in the mask, that pivotably supported sealing lip zone can then be
uniformly pressed against the bridge of the nose of the wearer of
the mask, without in that situation the occurrence of surface
pressures which considerably exceed the internal pressure of the
mask.
[0014] The particularly advantageous kinematics and hinge
characteristic of the mask cushion or pad formed by the sealing lip
device can in particular be achieved by local zones with a higher
load-bearing capability being provided in the region of the sealing
lip, which is adjacent to the nostrils or the upper lip.
[0015] In accordance with a particularly preferred embodiment of
the invention the zones of higher load-bearing capability are
formed by locally thickened zones of the sealing lip. The
transition of the locally thickened zones is preferably effected
along regions in the manner of the edge of a lens, or also in a
shallowly terminating configuration, possibly without the
transition between the zones being clearly perceptible.
[0016] In accordance with a particularly preferred embodiment of
the invention the locally thickened zones are supported on a mask
frame zone by way of a support structure which is formed in the
sealing lip. That mask frame zone is preferably of a thick-wall
nature and in that respect involves a wall thickness in the range
of between 3 and 6 mm.
[0017] The zones of higher load-bearing capability are preferably
of a pad-like nature, as is shown by way of example in FIG. 1 to
which reference will be subsequently made in greater detail.
[0018] A form of support for the mask pad, which is particularly
advantageous from ergonomic points of view is achieved if the zones
of higher load-bearing capability, in the region of the
face-contact zone, are each of a substantially crescent moon-shaped
configuration. The limbs of those zones of higher load-bearing
capability, which are provided in the region for bearing against
the upper lip, are preferably of a shortened configuration in such
a way that a zone of high elasticity and flexibility in opposite
relationship to the application direction is provided in the region
of the upper lip between the zones of higher load-bearing
capability. That higher degree of flexibility can advantageously be
achieved by also providing here a local fold structure or a
correspondingly thin-walled zone.
[0019] In accordance with a particularly preferred embodiment of
the invention the sealing lip device is mounted to a mask base
body. The mask base body can also be formed from an elastomeric
material, for example silicone rubber. In accordance with a
particularly preferred embodiment of the invention however the mask
base body is formed by a hard shell, for example comprising a fully
transparent material. The hard shell preferably has a conduit
connection facing in the application position towards the forehead
region of the mask wearer. As an alternative thereto it is also
possible for the hard shell to be provided with a central or
lateral connecting structure for coupling a respiratory gas
conduit.
[0020] Mounting the sealing lip device or the sealing pad to the
hard shell or a mask base body is preferably effected by using a
coupling structure. In accordance with a particularly preferred
embodiment of the invention that coupling structure comprises, on
the part of the hard shell, a peripheral bead portion and, on the
part of the sealing lip device, a frame portion with a
complementary receiving groove. The groove and the bead are
preferably such that in the case of an expansion of the mask pad,
caused by mask internal pressure, in the region of the coupling
structure, there are surface pressures which are always higher than
the internal pressure in the mask. That provides for a particularly
reliable sealing action, without the addition of adhesives.
[0021] In a particularly advantageous fashion, there are provided
means for fixing the position of the sealing lip device with
respect to the hard shell in the peripheral direction. Those means
can be formed for example by positioning projections or in
particular by apertures in the peripheral bead.
[0022] A prestressing is preferably imparted to the sealing lip
device, which prestressing is advantageously achieved by elastic
deformation upon coupling to the hard shell. That makes it possible
to definedly influence the deformation characteristics of the
sealing lip device. In particular it is possible to prestress given
zones of the sealing lip device in such a way that the formation of
wrinkle folds in the region of the face-sealing zone is
advantageously precluded.
[0023] In accordance with an advantageous embodiment of the
invention the frame portion is such that it extends substantially
in one plane. That permits the hard shell to be of a comparatively
flat structure and allows the mask pad to be prestressed in a
simple fashion.
[0024] As an alternative thereto however it is also possible for
the mask arrangement to be designed in such a way that the frame
portion is of a configuration which advances in the region of the
articulation axis relative to the zone of high load-bearing
capability. That makes it possible to already impart to the hard
shell itself a configuration which substantially corresponds to the
statistically most probable facial architecture.
[0025] Advantageously the wall thickness of the thin zone is in the
range of between 0.65 and 1.85 mm. That wall thickness imparts to
the mask a resistance to pressure which is sufficient even in the
case of mask pressures in the region of 15 mbars.
[0026] The wall thickness of the zone of high load-bearing
capability is preferably in the range of between 0.80 and 4 mm.
[0027] In accordance with a particularly preferred embodiment of
the invention the mask pad is produced by a multi-stage mold cavity
filling method. That makes it possible to impart to the zone of
high load-bearing capability, a coloring which differs from the
zone of low load-bearing capability. It is also possible to
definedly match the mechanical properties of the materials
respectively used for the respective zone.
[0028] The zone of high load-bearing capability is preferably
formed by two elastomeric portions which project up from the lower
corner region of the frame portion and which pass out into the
sealing lip in the form of flat limbs. The sealing lip itself is
preferably formed from an elastomeric material, in particular fully
transparent silicone rubber. The outside surface of the mask pad,
which comes directly into contact with the face of the mask wearer,
is preferably of a velvety matt finish. That affords an improved
feel when wearing the mask.
[0029] An embodiment of the invention which is particularly
advantageous from manufacturing procedure points of view is
afforded if the hard shell is injection molded to the sealing lip
device. Besides particularly reliable coupling of the hard shell or
the mask base body and the mask pad, that also precludes the
formation of a gap, which is disadvantageous from bacteriological
points of view.
[0030] In regard to a method of producing a sealing lip device for
a breathing mask, the above-specified object is attained by an
elastomeric material being introduced into a mold cavity formed by
a mold, at least partially setting in the mold cavity, and being
removed from the mold after opening thereof, wherein the
elastomeric material is introduced into the corresponding mold
cavity in two steps which occur in succession in time.
[0031] In that way it is possible to provide a mask pad which has a
single sealing lip which in the application direction affords
flexibility which is defined in accordance with the load-bearing
capability and the statistically expected architectural variance of
the corresponding zone of the face.
[0032] Advantageously, a carrier structure of the sealing lip
device and a thin-wall zone of the sealing lip are formed in steps
which are separate in terms of time, and possibly using materials
involving different mechanical properties and possibly color.
[0033] Preferably the carrier structure is formed in a first
injection step and the thin-wall zone is formed in a subsequent
second injection step. The operation of introducing the respective
material is preferably effected by injection or beforehand by
suitably introducing same into the mold cavity to fill it.
[0034] The mold cavity which is provided for filling with the
material forming the thin-wall zone is preferably defined by a mold
which delimits the outside of a sealing lip being lifted off a core
which delimits the inside of the sealing lip.
[0035] As an alternative thereto it is also possible for the
carrier structure to be formed by a mold cavity which is defined by
a core delimiting the inside of a sealing lip and an outer mold,
wherein to form the thin-wall zone of the sealing lip the outer
mold is changed and then the material for forming the thin zone is
introduced into the mold cavity which is now present and which is
intended for the thin-wall zone, and sets therein.
[0036] In the mold aspect of the invention, the above-specified
object is attained by a mold for producing a sealing lip device for
a breathing mask, comprising a mold core device which in
conjunction with an outer mold defines a mold cavity having a fold
portion.
[0037] It is advantageously possible in that way to produce the
sealing lip device for example in the context of a fully automated
silicone injection molding method.
[0038] In accordance with a particularly preferred embodiment of
the invention the outer mold is of a multi-part nature. Preferably
the outer mold comprises a mold half which delimits the outside
surface of the sealing lip and a mold half which co-operates with
said mold half and which delimits the rest of the region of the
outside surface of the sealing pad. The inner region of the sealing
pad is delimited by a preferably integral core device. With the
described two-part embodiment of the outer mold, it is possible for
an outer mold half to be withdrawn along a mold-opening axis which
extends in a direction in opposite relationship to the side at the
bridge of the nose or a direction remote from the upper lip sealing
zone. The bellows zone which is locally provided in the region of
the bridge of the nose and the mold-opening axis as well as the
configuration of the coupling frame of the mask pad are preferably
matched in such a way as to afford mold-opening angles at least in
the region of 2.degree..
[0039] In particular in this case the outside of the sealing lip,
which is towards the mask wearer, is preferably formed by an outer
mold portion in conjunction with the mold core device, wherein the
outer mold portion has a peripherally extending mold cavity channel
which defines the outside of the sealing lip.
[0040] The outer separation edge of the mold cavity channel
preferably extends in the region of the outer peripheral edge of
the sealing lip. That advantageously avoids any burrs in the region
of the face-contact surfaces.
[0041] In accordance with a particular aspect of the invention, an
embodiment, which can be particularly advantageously implemented
from production procedure points of view, of a leakage device for
the discharge of at least partially consumed respiratory air into
the ambient atmosphere is afforded by a breathing mask having a
mask body and sealing pad device which is formed from an
elastomeric material and which in conjunction with the mask body
delimits a mask internal space and an outlet device for the
discharge of at least partially consumed respiratory gas out of the
mask internal space, wherein the outlet device has a flow path
portion which is at least partially defined by the sealing pad
device.
[0042] This measure can also be used independently of the
above-described design configurations. Advantageous developments of
this combination of the invention, which is independent per se, are
set forth in the appendant claims.
[0043] Further advantageous configurations of the invention are
recited in the appendant claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Further details of the invention will be apparent from the
description hereinafter with reference to the drawing in which:
[0045] FIG. 1a shows a perspective view of a mask pad in accordance
with a first embodiment of the invention with a local bellows
structure and pad-like zones of increased load-bearing capability
in the region of the sealing lips adjacent to the nostrils in the
application position,
[0046] FIGS. 1b, 1c and 1d provide illustration and accompanying
explanation for the perspective view of FIG. 1a,
[0047] FIG. 2a shows a simplified side view of a further breathing
mask with a fold indentation and a frame portion extending
substantially in one plane
[0048] FIG. 2b shows a simplified side view of a further breathing
mask with a rolling bellows and a frame portion extending
substantially in one plane,
[0049] FIG. 3a shows a simplified side view of a further embodiment
of a mask pad, also with a bellows-like fold indentation and an
indicated adaptation or articulation axis,
[0050] FIG. 3b shows a simplified side view of a further embodiment
of a breathing mask with a fold provided only in the rear third of
the mask pad,
[0051] FIG. 4 shows a simplified plan view of a sealing lip and
diagrams for qualitative illustration of preferred matching of the
load-bearing capability of the sealing lip,
[0052] FIG. 5a shows a view in section to describe a preferred
embodiment of a fold region with a hinge characteristic established
by zones of differing wall thicknesses,
[0053] FIG. 5b shows an enlarged view of a portion of the sectional
view illustrated in FIG. 5a,
[0054] FIG. 5c is a diagrammatic sketch showing the mechanics of
the microsealing lip structure of FIG. 5a,
[0055] FIGS. 6, 6a, 6b, 6c, 6d, 6e, 6f, and 6g show diagrammatic
views to describe preferred cross-sectional configurations in the
case of a sealing lip device according to the invention,
[0056] FIG. 7 shows a diagrammatic view to describe the flexibility
of the hinge-like suspension for a sealing lip,
[0057] FIG. 8 shows a diagrammatic view to describe a preferred
measure for fixing the mask pad in the peripheral direction,
[0058] FIG. 9 shows a further diagrammatic view to describe a
preferred structure of a mold in conjunction with advantageous
configurations of a mask base body (hard shell),
[0059] FIG. 10 shows a simplified view in section to describe a
fold portion with a plurality of fold indentations and a defined
hinge characteristic,
[0060] FIG. 11 shows a perspective view of a further preferred
embodiment of a breathing mask with a mask sealing pad provided
with a local bellows structure,
[0061] FIG. 12 shows a perspective view of the breathing mask of
FIG. 11 from below,
[0062] FIG. 13 shows a simplified view in section through the
sealing device which is disposed on the upper lip, to describe the
substantially smooth-wall transition of the sealing lip into the
hard shell mask body,
[0063] FIG. 14a shows a simplified view in section through a
sealing lip with integrated leakage opening,
[0064] FIG. 14b shows a simplified view in section through a
sealing lip with integrated leakage opening, but with a flow path
partially delimited by the mask frame,
[0065] FIG. 14c shows a simplified view in section through a
sealing lip with integrated leakage opening, with a flow path which
is formed in the mask frame and which passes into the sealing lip
frame portion,
[0066] FIG. 14d shows a simplified view in section through a
sealing lip with integrated leakage opening, but with mutually
aligned passages in the hard shell and the sealing lip device,
[0067] FIG. 14e shows a simplified view in section through a
sealing lip with integrated leakage opening, but with a portion
which is extended upwardly in a bib-like configuration from the
interior to a through opening, and with a through opening formed
therein,
[0068] FIG. 14f shows a side perspective view of the sealing pad
device of FIG. 14b,
[0069] FIGS. 15a, 15b, 15c, and 15d show simplified diagrammatic
views of preferred cross-sections of the flow paths, and
[0070] FIG. 16 shows a simplified diagrammatic view in principle to
describe preferred leakage zones.
DETAILED DESCRIPTION OF THE INVENTION
[0071] The sealing lip device which is shown in FIG. 1a and which
is in the form of a mask cushion or pad 1 is made from an
elastomeric material, here transparent silicone rubber.
[0072] The mask pad 1 includes a sealing lip 3 which extends around
the nose receiving opening 2. The sealing lip 3 has an outer
surface which is curved convexly in the embodiment illustrated
here.
[0073] The sealing lip 3 is of such an arrangement and
configuration that it has, of itself, zones of differing
load-bearing capability. In the embodiment illustrated here that is
achieved by suspension, which is flexible in opposite relationship
to the application direction Z, of the sealing lip zone a provided
for bearing against the bridge of the nose (see FIG. 1b).
[0074] In addition thereto, in the region of the zone b1, b2 (FIG.
1b) adjacent to the nostrils, the sealing lip 3 is of such a
configuration that here it is of a higher load-bearing capability.
That provides for pivotability of the mask pad about an adaptation
axis X, which extends transversely through the mask pad in the
region identified in FIG. 1b by the letter e.
[0075] The higher load-bearing capability is achieved here by zones
4 which are thickened in a pad-like manner and which here
advantageously run into the sealing lip 3 in a crescent moon-like
configuration. The zones 4 of higher load-bearing capability are
respectively supported at a support wall portion 5 which is also
comparatively thick-walled. The support wall portions 5 also form
an integral component part of the mask pad 1 and are embodied in
the form of thick-wall zones of the front peripheral wall which
extends in the zones b1, c and b2.
[0076] The degree of flexibility in opposite relationship to the
application direction decreases along the sealing lip 3, starting
from the zones 4 of high load-bearing capability, to the zenith Q
at the side at the bridge of the nose, and then slowly rises to the
outer edge point R.
[0077] In the illustrated embodiment, the mounting of the zone a of
the sealing lip 3, which is yielding in opposite relationship to
the application direction Z, is achieved by means of a folding
bellows structure of differing load-bearing capability.
[0078] The differing load-bearing capability is achieved here both
by the geometry and arrangement of the bellows structure and also
by a particular wall thickness configuration. That wall thickness
configuration will be discussed in greater detail hereinafter in
particular with reference to FIGS. 5a-6g.
[0079] The mask pad 1 further includes a peripherally extending
frame 8 provided with a fixing profile means which is of a
complementary configuration to a fixing profile portion provided on
a mask base body (not shown).
[0080] The peripheral length of the frame 8 and the configuration
thereof around a central axis z of the mask pad 1 are selected in
such a way that, in conjunction with a mask base body, the
arrangement provides for defined prestressing of the mask pad 1, in
particular a tendency towards forward curvature in an outward
direction.
[0081] In the illustrated embodiment the wall thickness of the
sealing lip 3 is in the range of between 0.6 and 3.2 mm.
[0082] The configuration of the peripheral edge u which borders the
nose receiving opening 2 is selected in such a way that there are
formed two segments s1, s2 (FIG. 1d) which project inwardly
slightly relative to the axis z of the mask.
[0083] By virtue of the configuration of the peripheral edge u
being matched to the convex curvature of the sealing lip 3, it is
possible to achieve a deformation characteristic with which an
expansion of the sealing lip 3 in the region of the peripheral edge
results in a definedly increased surface pressure against the face
of the wearer of the mask.
[0084] Provided in a front end center region c is a further zone of
reduced load-bearing capability. That definedly reduced
load-bearing capability is afforded here by a markedly reduced wall
thickness. It is also possible to provide local folding bellows
structures or rolling bellows structures in the zone c.
[0085] A particularly preferred embodiment of a sealing lip device
is afforded by virtue of the fact that integrated into the same are
outlet openings 50, by way of which a defined flow of gas can flow
away out of the interior (or plenum chamber) of the breathing mask.
Those outlet openings are preferably of an outwardly conically
tapering cross-section, as shown in FIG. 1c.
[0086] Preferably, those outlet openings are initially closed for
example by a thin film and are then opened as required for example
by puncturing with a needle. As can further be seen from this
sketch the mask pad 1 can be mounted to a mask base body 12 by way
of a frame portion 8. For that purpose the arrangement preferably
has a peripheral bead structure of a crochet needle-like
cross-section and with rounded edges.
[0087] FIGS. 2a and 2b show side views of further embodiments of a
mask pad 1. In those views, the frame 8 extends substantially in a
flat frame-defining plane f.
[0088] The mask pad 1 also has in the sealing region of the bridge
of the nose a local folding bellows structure 9 which provides for
flexible suspension of the sealing lip 3.
[0089] A fold indentation 10 is also provided in the front region c
(definition similar to the FIG. 1b). The arrangement afforded in
that way defines an adaptation and articulation axis X or an
instantaneous center of rotation about which the sealing lip 3 can
be elastically tilted. The arrangement here is such that tilt
angles .alpha. in a range of up to 15.degree. are possible. Besides
the tilting movement itself the sealing lip 3 can also experience
individual deformation, corresponding to the facial architecture.
In particular the peripheral edge u of the nose receiving opening
is stretched.
[0090] When relatively large tilt angles are involved, here the
bellows structure becomes effective as an abutment device and
limits in an also elastically yielding manner further engagement of
the bridge of the nose into the mask pad 1.
[0091] The bellows structure 9 has the greatest indentation depth t
in the region of the end which is towards the bridge of the nose.
That indentation depth t gradually decreases to the front end E of
the bellows structure 9.
[0092] In the embodiment illustrated here, the end of the bellows
structure 9 is of a rounded configuration. Advantageously, provided
in the region of the front end E of the fold indentation is a
microfold structure e which provides for a more uniform reduction
in stresses in the material in that region. That affords improved
durability.
[0093] FIG. 3a shows a further embodiment of a mask pad 1 in
conjunction with a mask body 12 which is only indicated.
[0094] This embodiment also has a local folding bellows structure
9. The geometry of this bellows structure 9 is so selected that the
fold flanks 9a, 9b extend inclinedly relative to each other.
Overall in this case also the indentation depth t in the region of
the end towards the bridge of the nose is larger than in the other
regions. The mask pad 1 also defines an adaptation axis X which
extends in the region of the zones c1, b2 and c at the level of the
nostrils of the wearer of the mask.
[0095] The mask pad 1 also has a higher degree of flexibility in
opposite relationship to the application direction Z by virtue of
the suspension arrangement provided here for suspending the sealing
lip 3 at a local bellows structure 9, in the region of the zone a
which seals off the bridge of the nose.
[0096] FIG. 3b shows a further view of a breathing mask with a mask
pad 1 according to the invention. The mask pad 1 is here fixed by
way of a frame 8 to a mask base body 12. A bellows structure 9 is
provided here in the region of the portion of the sealing lip 3
which seals off the bridge of the nose. In a departure from the
above-described embodiments in this case also the peripheral wall
of the mask pad is also of thin-wall configuration in the region of
the bellows structure 9. The mask pad 1 is stretched onto the mask
base body 12 with considerable expansion and stretching of the
frame 8.
[0097] FIG. 4, in conjunction with a plan view onto a half of the
sealing lip 3, illustrates the load-bearing capability and the
flexibility of the mask pad 1.
[0098] The lowest level of flexibility E of the mask pad 1 obtains
in the region b. The highest level of flexibility obtains in the
region a which covers over the bridge of the nose and the upper
side flanks of the nose of the mask wearer. Obtaining in the region
c in addition to the flexibility in opposite relationship to the
application direction Z there is also a relatively high level of
flexibility in the radial direction.
[0099] The adaptation axis A extends through the zone b of
relatively high load-bearing capability. When a predetermined depth
of penetration into the mask pad 1 is exceeded, the bellows
structure becomes operative in a region d as an abutment device and
in that case causes a rapid rise in the pressure force F
transmitted by way of the sealing lip 3, as is indicated by the
dash-dotted line portion fl.
[0100] The particular mechanical properties of the suspension
arrangement for the sealing lip 3 are preferably determined by the
wall thickness in the region of the bellows structure 9 and by the
indentation depth and the orientation of the bellows flanks 9a, 9b
(FIG. 3a).
[0101] FIGS. 5a and 5c show a preferred configuration of the wall
thicknesses of the bellows structure 9. The mask pad 1 is fixed to
a mask base body 12 in this case by way of a rounded profile
structure 12a which extends along the frame 8. In the illustrated
embodiment that profile structure 12a is of a crochet needle-like
cross-section. Provided at least in a portion-wise manner in the
region of the contact zone between the frame 8 and the mask base
body 12 are peripherally extending profile legs 15 which, even in
the case of a considerable relative movement, provide a secure
sealing action.
[0102] Beneath the frame 8 there is initially a thick-wall portion
16 which gradually reduces to a first bellows hinge location or
vertex 17. That bellows hinge location or vertex 17 is adjoined by
a first bellows flank limb 9b. That bellows flank limb 9b has in
cross-section zones of differing wall thickness and extends to a
bellows inner hinge location 18 defined by a thin-walled zone. The
variable wall thickness of the flank limb 9b forms an indentation
region or thin wall portion 77 that promotes a hinged motion around
the hinge location or vertex 17 (see FIG. 5a).
[0103] The bellows inner hinge location or vertex 18 is in turn
adjoined by a second bellows flank limb 9a which also has zones of
differing wall thickness. The variable wall thickness of the flank
limb 9a forms another internal indentation region or thin wall
portion 78 that promotes a hinged motion around the hinge location
or vertex 18.
[0104] Finally, the sealing lip 3 is suspended on the second
bellows flank limb 9a at a vertex 79. The sealing lip 3 is here
extremely thin-walled in comparison with the bellows structure
9.
[0105] The sealing pad cross-section illustrated here corresponds
in qualitative terms to the sealing pad cross-section in the region
of the zone identified as a1 in FIG. 4.
[0106] In the course of applying the mask pad to the face of a mask
wearer, the sealing lip 3 firstly bears against the face. The
bellows flank limbs 9a, 9b are then deflected resiliently inwardly,
corresponding to the depth of engagement of the bridge of the nose,
as illustrated by the arrows P1 and P2. In the case of particularly
deep engagement of the bridge of the nose the inner surface of the
sealing lip 3 possibly comes into contract in the region of the
zone k with the inside surface, which faces theretowards, of the
bellows flank limb 9b. The bellows flank limb 9b in turn can bear
on the outside surface, which faces theretowards, of the bellows
flank limb 9a.
[0107] The kinematics of the sealing pad suspension configuration
will be clear by reference to FIG. 5c. Thus the frame can be viewed
as a fixed suspension means K1 at which the bellows flank limb 9b
is mounted pivotably at the hinge location or vertex 17. The
inherent elasticity of the elastomeric material in the region of
the hinge location or vertex 17 is symbolically indicated by the
spring F1.
[0108] The bellows inner hinge location or vertex 18 also involves
an inherently elastic characteristic which is indicated by the
spring F2. The loose mounting K2 and the spring F3 are due to the
fact that this involves a spatial, ring-like structure which also
carries forces in the radial direction.
[0109] The hinge location or vertex 18 is adjoined by the bellows
flank limb 9a and the same is adjoined by the diaphragm-like
sealing lip 3.
[0110] As illustrated in FIG. 5b, provided along the inner
peripheral edge u is a microsealing lip structure by which a
sealing edge which terminates in a thin configuration is slightly
prestressed outwardly. The microsealing lip structure has a bead
portion 19 which increases the resistance to tearing of the sealing
lip 3.
[0111] The mechanics of this microsealing lip structure is
indicated in FIG. 5c by a spring F4 and a hinge location 20. The
sealing lip which is elastically suspended in that way, as
indicated by the small arrows, can be urged, flexibly against the
surface of the face of the mask wearer, as a consequence of the
internal pressure obtaining in the interior (or plenum chamber) of
the mask.
[0112] As can be seen from FIG. 6 the mask pad 1 is preferably of
differing cross-sections along its configuration around the axis Z
of the mask, as is diagrammatically indicated here.
[0113] The cross-section illustrated in FIG. 6a has a marked hinge
characteristic with abutment properties.
[0114] The cross-section illustrated in FIG. 6b already has a lower
hinge characteristic and a smaller fold indentation.
[0115] In the regions of the cross-sections illustrated in FIGS. 6c
and 6d the bellows property decreases still further.
[0116] The higher load-bearing capability of the cross-sections
illustrated in FIGS. 6d and 6e is achieved by local thickenings R1,
R2 which extend lens-like into the sealing lip. In the zones of
high load-bearing capability, it is possible to forego the bellows
structure, as has happened here.
[0117] The alternative cross-sections illustrated in FIGS. 6f and
6g are such that there is flexibility in the directions r1 and r2
indicated here. That affords improved adaptability, in terms of the
upper lip architecture, immediately beside the load-bearing
zones.
[0118] It is also possible for the bellows structure 9 to be of a
thin-wall nature. The kinematics of a structure of that kind is
diagrammatically shown in FIG. 7. The diaphragm-like sealing lip 3
is here suspended on two limbs (bellows flank limb 9a, 9b). This
embodiment, even with low internal pressures in the mask,
guarantees a high level of adaptability. The elasticity
characteristics are illustrated, with reference to a unit force,
for all loading angles, by the polar diagrams II1, II2 which are
diagrammatically shown here. As can be seen, a defined degree of
adaptability is afforded by the suspension arrangement according to
the invention for the sealing lip 3, not only in opposite
relationship to the application direction Z but also in all other
directions. The location vectors .pi.1, .pi.2, .pi.3 and .pi.4
clearly show that flexibility in the region of the bellows inner
hinge location or vertex 18. The mobility options of the bellows
inner hinge location or vertex 18 are also transmitted (under the
influence of the mask pad peripheral forces) to the suspension
region of the sealing lip 3.
[0119] FIG. 8 diagrammatically shows a profile structure 21 which
is provided in respect of a mask base body 12 and which
advantageously provides for reliable fixing of the mask pad in the
peripheral direction. The illustrated embodiment for that purpose
has a plurality of individual fixing projections 22 along the
periphery of the mask base body 12. As an alternative thereto or
also in combination with that measure, it is also possible to
provide further fixing means, in particular peg-like
projections.
[0120] FIG. 9 shows in greatly simplified form the structure of a
mold for producing the mask base body 12. By virtue of the aperture
in the peripheral bead 23 in the region of the respective strap
loops, it is possible for the strap loops to be injection molded
integrally with the mask base body 12, without the need for sliding
mold portions in that respect.
[0121] In the embodiment of the mask base body 12 diagrammatically
illustrated here, provided in parallel with a respiratory gas
passage 24 is a secondary passage 25 by way of which for example
pressure measurement can be effected, without reductions in
cross-section occurring in that case.
[0122] The tool here is of a three-part construction and includes
an upper mold half 26, a lower mold half 27 and a sliding mold
portion 28 which can be withdrawn in the direction r3 from the
respiratory gas passage 24.
[0123] Although the invention has been described hereinbefore with
reference to preferred embodiments in which there is a single fold
indentation which does not extend around the entire periphery of
the mask pad, the invention is not limited to embodiments of that
kind.
[0124] For example it is possible for the bellows structure to be
provided with a plurality of fold indentations, of which possibly
one or more extend around the entire periphery of the mask pad.
[0125] An example of a corresponding cross-sectional configuration
is shown in FIG. 10. The mask pad 1 which is here fixed to a mask
base body 12 which is only indicated in respect of a portion
thereof, by way of a peripheral bead structure of a crochet
needle-like cross-section, has two local fold indentations 39, 49.
The wall of those local fold indentations 39, 49 is matched in
regard to a defined hinge and flexibility characteristic.
[0126] In this embodiment the sealing lip 3 is of a comparatively
thick-wall nature. That cross-section is suitable in particular for
silicone rubber material with an extremely low Shore hardness.
[0127] The breathing mask shown in FIG. 11 includes a mask base
body 12 which is made from a preferably fully transparent
thermoplastic material. Provided in a wall portion which in the
application position of the mask is adjacent to the forehead region
of the mask wearer is a connecting portion 60 which here is of a
polygonal cross-section.
[0128] The sealing pad device 3 is fixed to the mask base body 12
by way of a peripheral bead structure (not visible here). The
sealing pad device 3 has a bellows structure which extends locally
from the upper end region to an adaptation axis A. Provided in the
region of the adaptation axis A on both sides of the sealing pad
are zones of higher load-bearing capability which are formed by
thicker-walled, spherically curved zones of the sealing pad
device.
[0129] For the purposes of fitting the breathing mask to the face
of a mask wearer, provided at both sides of the mask are fixing
devices 61, by way of which a head band 61a can be coupled to the
breathing mask.
[0130] On its top side the mask body 12 is provided with a
projection 62 by which the mask body generally is stiffened,
thereby affording an improved characteristic in terms of sound
conduction through solids.
[0131] Also provided in the region of the top side of the mask body
12 are a plurality of outlet openings 63, 64, by way of which a
low-noise, directed discharge flow of partially consumed
respiratory air can occur from the interior (or plenum chamber) of
the mask. The discharge of that leakage gas flow is promoted by a
break-away edge 65 of a spoiler-like configuration. The openings 64
direct the flow substantially in the direction indicated by the
arrow P1. The openings 63 which are also provided on the opposite
side (not visible here) of the projection 62 open in the directions
P2 and P3.
[0132] FIG. 12 shows the breathing mask of FIG. 11 from a direction
of view which is directed inclinedly from below onto the zone 4 of
high load-bearing capability. It is also possible to see here,
beside the local bellows structure 9, the region of the sealing lip
3 which bears against the face of the mask wearer. In the region of
the zone a the mask is distinguished by a high level of
adaptability to different nose bridge heights. In the zones b1 and
b2 the mask pad 1 is supported in a defined manner against the face
of the mask wearer. In the region c once again there is a higher
level of flexibility and a higher degree of adaptability to
different upper lip contours.
[0133] The mask pad is of such a design configuration that there is
a relief of load in the region of the zones b1 and b2, as a
consequence of the internal pressure in the mask which occurs in
the context of over-pressure artificial respiration. The surface
pressure of the mask pad in the region of the zones a and c is
substantially determined by the internal pressure in the mask. In
the peripheral direction the sealing pad 1 has a high level of
radial stiffness whereby the tendency to oscillation of the sealing
pad in relation to alternating artificial respiration pressures is
markedly reduced.
[0134] FIG. 13 is a greatly simplified view in section through the
region of the sealing lip device 3, which fits on the upper lip 70
of a mask wearer. In a transitional region from the sealing pad
device into the hard shell body 12, the configuration of the
cross-sections of the sealing pad device 3 and the hard shell body
12 is such that there is a substantially smooth transition in
respect of the respective internal surfaces. That ensures a
favorable flow path directly in the region of the nostrils of the
mask wearer.
[0135] As indicated, in this case also there is a local bellows
structure 66 which ensures improved adaptability to different upper
lip architectures.
[0136] FIG. 14a shows a portion of the arrangement illustrating the
transitional region between the hard shell body 12 and the sealing
pad device 1. Formed directly in the sealing pad device 1 is a
leakage opening 67 which is here of a cross-section which decreases
in the discharge direction. The cross-sections of that leakage
opening 67 are preferably of the configuration diagrammatically
shown in FIG. 15.
[0137] FIG. 14b shows a further embodiment of a leakage opening 68
which is integrated into the sealing pad device 1. In the
embodiment illustrated here a wall formed by the hard shell body 12
extends into the flow path. This embodiment can be cleaned in a
particularly advantageous manner as the flow path is exposed over a
large area after removal of the sealing pad device 1 from the hard
shell body 12. Illustrated FIG. 14f is a view of a detail of that
sealing pad, in the direction of view identified as x1. As can be
seen therein the peripheral bead 12a of the hard shell body 12
extends partially into the recess 69 formed in the cushion pad
device 1.
[0138] In the embodiment shown in FIG. 14c, provided in the region
of the joint between the hard shell body 12 and the sealing pad
device 1 in the hard shell body is a channel portion 76 by way of
which there can be a discharge flow of gas, as indicated by
dash-dotted lines. The exit region of the channel portion 76, as
illustrated, opens into an outlet passage 71 which is defined
jointly by the sealing pad device 3 and the hard shell body 12.
[0139] In the embodiment shown in FIG. 14d, provided in the hard
shell body 12 is at least one outlet passage 72 which goes into an
aligned discharge passage 73 in the sealing device 1.
[0140] FIG. 14e shows an embodiment of a leakage device in which a
wall portion 74 which is integral with the sealing pad device 1 is
taken from the interior (or plenum chamber) to an outlet opening
region 75 of the hard shell body 12. That wall portion 74 is here
provided with an outlet opening 67 which tapers conically in the
discharge direction and which is arranged coaxially with respect to
a preferably considerably larger outlet opening 75a.
[0141] The flow paths described with reference to FIGS. 14a through
14e are preferably of at least one of the cross-sections 78-84
diagrammatically shown in FIGS. 15a-15d.
[0142] FIG. 16 indicates a preferred location for providing the
discharge flow openings which are provided jointly with the sealing
pad device 1 or also separately therefrom. Preferably the discharge
flow occurs in the region of the zone c in combination with the
zones b1 and b2, but preferably larger volume flows are admitted in
the region c.
[0143] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *