Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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84538pct
Microstructured high pressure nozzle with an in-built filter function
The present invention relates to a microstructured high pressure nozzle with
built-in filter
function for a high pressure atomiser for nebulising medical fluids.
Prior art
Inhalation therapy is of ever increasing importance in the treatment of
respiratory complaints
such as asthma or COPD.
Since chlorofluorocarbon-operated propellant formulations were banned there
has been more
and more success in developing equally effective or better approaches to the
production of
aerosols for inhalation into the lungs.
International Patent Applications WO 91/14468 and WO 97/12687 provided a new
approach
to inhalers which are characterised not only in that they deliver a propellant-
free aerosol on a
well-tolerated aqueous base the droplet distribution of which is tailor-made
for absorption
into the lungs, but also in that they are a handy size which is comparable to
the size of the
known propellant-driven inhalers.
This nebuliser, also known as Respimat , is able to atomise liquid
pharmaceutical solutions
in an amount of preferably less than 20 microlitres by a single operation into
an aerosol with
an average particle size of less than 10 microns. As a result the
therapeutically effective dose
of the drug can be administered to the patient in tiny volumes.
In this nebuliser, a pharmaceutical solution is first of all pumped out of a
reservoir through a
cannula with an integrated valve body into a pressure chamber and from there
is converted
into a aerosol intended for the lungs, using high pressures of up to 500 bar,
through a nozzle
and sprayed. The pressure is generated by means of a helical spring which is
re-tensioned by
the patient by the application of slight force before each actuation. At the
same time as the
tensioning action the pressure chamber is filled with the pharmaceutical
solution. Details of
this mechanism can be found in Figures 6a and 6b of WO 97/12687.
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This atomiser essentially consists of
- an upper housing part,
- a nozzle in the upper housing part,
- a spring housing which is connected to the upper housing part and on which
the lower
housing part is placed,
- a storage container which can be inserted in an inner space defined by the
spring
housing and
- a hollow plunger with an integrated valve body, the hollow plunger leading
from the
storage container towards the nozzle.
In the upper housing part there is also a pump housing on one end of which is
located the
nozzle body with the nozzle or nozzle arrangement. The hollow plunger also
opens into the
pump housing. There is a pressure chamber between it and the nozzle.
The spring housing is rotatably connected to the upper housing part and the
spring is finally
tensioned by the rotary movement via a tensioning locking mechanism in the
upper housing
part.
The tensioning of the spring moves a power takeoff flange which is located in
the upper part
of the spring housing and from which the hollow plunger is suspended.
The hollow piston with valve body corresponds to an apparatus disclosed in WO
97/12687.
The nozzle used is preferably a nozzle or nozzle body produced by
microengineering. A
microstructured nozzle body of this kind is disclosed for example in WO-
94/07607 or WO
99/16530. The nozzle of WO 99/16530 is the starting point for the present
invention.
Reference is therefore made to the entire specification of WO 99/16530,
particularly the
embodiment claimed by EP 1017469 B 1, with all its features.
The nozzle body consists of two sheets, preferably of glass and/or silicon,
securely fixed
together, at least one of which has one or more microstructured channels which
connect the
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nozzle inlet end to the nozzle outlet end. The nozzle outlet end with the
nozzle openings is
preferably on the opposite side from the nozzle inlet end.
The nozzle inlet end [has] a fluid inlet or a plurality of fluid inlets. The
inlet or inlets may be
constructed as a prefilter or prefilters. Alternatively, the prefilter may be
connected separately
downstream of the inlet/ inlets in the direction of flow.
After passing through the prefilter the fluid flows through a main filter
formed by a plurality
of projections.
Behind the main filter, viewed in the direction of flow, is a filtrate
collecting chamber for
fluid which has already been filtered.
From the fluid collecting chamber the fluid goes to an outlet which is
preferably constructed
in the form of a nozzle with one or more nozzle openings.
The main filter comprises a plurality of projections arranged in rows,
preferably in a zigzag
shape, projecting from a - preferably flat - base plate and hence an integral
part of the base
plate. The base plate is completely covered by a - preferably flat - cover
plate. This forms a
plurality of channels between the projections, the base plate and the cover
plate. These
channels form a passage from the inlet side to the outlet side of the filter
nozzle. The spacing
between the base plate in the area around the projections and the cover plate
within a row of
projections is about the same size as the width of the channels on the side of
the projections
where the fluid enters the series of channels. Unfiltered fluid enters the
filter through one or
more oblong inlet slot(s). The inlet slot(s) are about the same height as the
projections
protruding from the base plate on the inlet side of the filter.
The base plate preferably consists of silicon. This plate is preferably
covered from above by a
glass plate.
To produce the nozzles, the following steps are carried out-
- structuring a batch of the base plates;
- joining the batch of base plates and cover plates together; and
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- separating the individual nozzle arrangements.
The base plate is preferably structured by etching techniques in a manner
known per se. The
heights of the structures described above are between 2 and 40 microns,
usually between 3
and 20 microns, preferably between about 4 and 14 microns, and particularly
between 5 and 7
microns. The material used for the base plate is preferably a monocrystalline
silicon, as it is
cheap and available in a state (i.e. in wafers) in which it is sufficiently
flat and parallel with a
slight surface roughness, and it can be attached to the cover plate without
the additional
application of adhesives or other materials during the subsequent connection
process. In
order to produce a plurality of nozzle arrangements in parallel manner, a
plurality of
structured base plates are made from a silicon wafer.
After structuring the silicon plate is cleaned. The silicon plate is then
attached to a cover plate
by anodic bonding (cf. US Patent 3,397,278 of 13.8.1968, Pomerantz et al.).
Suitable cover plates may be, for example, sheets of glass such as alkali
borosilicate glass,
e.g. Pyrex, (#7740 Corning) or Tempax (Schott). These may be attached by
anodic bonding of
the silicon and glass.
After the bonding process the composite structure is divided into individual
units (e.g.
squares) using a high speed rotating diamond circular saw.
This known filter has set out to achieve the objective of economically
producing a nozzle of
this kind for an inhaler of the type mentioned above (Respimat ).
Surprisingly, it has now been found that the nozzles in their entirety exhibit
a spray pattern
which is more uniform and advantageous for long-term use if the configuration
of the
microstructures inside the nozzle is modified.
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Description of the invention
Against this background embodiments of the present invention may improve the
average spray pattern through a plurality of nozzles.
Further embodiments may avoid substantially increasing the flow resistance in
the
5 nozzle.
Other embodiments may use the nozzle according to the invention in an inhaler
of the
Respimat type.
Some embodiments relate to microstructured nozzle comprising: an inlet for
unfiltered
fluid, an outlet for filtered fluid defining a flow direction, a main filter
between the inlet
and outlet, the main filter comprising a plurality of zigzag projections
extending
transversely to the flow direction from a base plate, defining a plurality of
channels
and forming spikes in directions of the inlet and the outlet, and a filtrate
collecting
chamber between the main filter and the outlet, the filtrate collecting
chamber
comprising a plurality of pillar-shaped built-in elements extending from the
base plate
transversely to the flow direction covering an area between the outlet and the
main
filter and at least part of an area extending between the zigzag projections
directed
towards the outlet, wherein one or more spacings between the built-in
elements, each
of which forms a throughflow channel for the liquid passing through, are such
that a
resulting cross sectional area transverse to the direction of flow which is
effectively
permeable to the liquid is greater than a corresponding effective cross
sectional
surface area of the throughflow channels formed by the projections of the main
filter
such that the built-in elements do not substantially increase a flow
resistance.
In some embodiments in the nozzle of the type in question a second type of
microstructure, which differs from the filter structure, is formed in the
region between
the filter structure and the nozzle outlet, i.e. the filtrate collecting
chamber. This
second type of microstructure is referred to hereinafter as the secondary
structure
and the filter structures are classed as the primary structure. In the
direction of flow
this secondary structure comes after the primary structure.
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5a
According to some embodiments of the invention, in order to form the secondary
structure in the filtrate collecting chamber additional built-in elements are
constructed.
Preferably, they are cylindrical elevations extending from the bottom of the
base plate
to the cover plate. They are preferably cylinders of circular cross section.
It is advantageous to use built-in elements the height of which corresponds to
the
height of the filtrate collecting chamber.
The built-in elements may be formed out of the base plate.
In preferred embodiments, the built-in elements are arranged in parallel rows
in an
ABAB arrangement with preferably equidistant intervals within rows A and B and
between rows A and B. The adjacent rows A and B are preferably displaced in
the
direction of flow by the diameter of the built-in elements. The use of built-
in elements
of circular cross section produces a geometry in which each of the built-in
elements
forms the centre of an equilateral
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hexagon, each angle being formed by an adjacent built-in element (hexagonal
design).
Naturally, this applies only partly or not at all to the built-in elements
positioned at the edge.
The dimensions of the built-in elements are selected so that they do not
substantially increase
the flow resistance. This is achieved by making the spacings between the built-
in elements,
each of which forms a throughflow channel for the liquid passing through, such
that the
resulting cross sectional area perpendicular to the direction of flow which is
effectively
permeable to the liquid is greater than the corresponding effective cross
sectional surface area
of the throughflow channels formed by the filter structures. Thus the flow
characteristics of
the liquid inside the nozzle are most strongly influenced by the structures of
the main filter.
The cross section of the built-in elements is preferably such that the flow
resistance for a fluid
flowing through is minimised. Round or oval cross sections are preferred for
this.
As an alternative to the cross sections described above they may also be
triangular,
trapezoidal or rectangular, while the angles should be aligned in the
direction of flow.
Advantageously there may be embodiments in which the dimensions and the
spacings of the
built-in elements relative to one another are such that they influence the
vaporisability of the
solution, by making use of the surface tension of the fluid.
Most preferably, the built-in elements have a spacing in the range from 0.005
mm to
0.02 mm. According to a preferred feature the built-in elements themselves
have a diameter
in the range from 0.005 mm to 0.02 mm. The spacings should be greater than the
smallest
spacings of the structures which form the zigzag-shaped filter structure.
The density of the built-in elements is preferably 200,000 to 300,000 per
square centimetre,
more preferably 250,000 per square centimetre.
However, it has also proved favourable to construct the built-in elements with
a concave or,
alternatively, a convex circumferential wall.
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Advantageously the structures of the main filter are projections extending in
a zigzag
configuration over the entire width of the interior of the nozzle. The spikes
in this
configuration point alternately in the direction of the inlet and outlet. An
imaginary central
line at right angles to the main direction of flow divides the configuration
into two areas of
roughly equal size.
Because of the zigzag arrangement of the built-in elements of the main filter,
the direction of
the fluid is changed substantially at right angles, viewed from the original
direction of flow.
Then in the fluid collecting chamber the direction of flow is changed again,
this time back
into the opposite direction to the first direction of rotation, at an internal
angle of less than 90
0
The above-mentioned projections may be arranged side by side over the entire
width of the
filter in order to build up the zigzag-shaped configuration.
In a first preferred embodiment the built-in elements are formed on the outlet
side behind the
zigzag configuration in the direction of flow. The built-in elements may
extend from the
imaginary central line of the zigzag-shaped configuration to the nozzle
openings.
Alternatively in a second embodiment the built-in elements may be formed right
into the
spikes of the filter system projecting in the direction of the inlet, but
preferably with the
exception of the region in front of the zigzag-shaped configuration.
In a third alternative embodiment the built-in elements may be arranged in the
direction of
flow both in front of and behind the zigzag configuration.
In an alternative embodiment the projections of the main filter may be
arranged in several
rows in a cascade. The projections arranged closer to the inlet side of the
filter may be larger
than the projections arranged more on the outlet side of the filter.
The spacing between the flat base plate and the flat cover plate in the area
around each row of
projections arranged in a cascade is about the same as the width of the
channels on the side of
the projections where the fluid enters the row of channels. This spacing is
between half and
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twice the width of the channel. This spacing may decrease from row to row -
viewed in the
direction of flow. The channels thus have a substantially square cross section
at their entry
end for the fluid.
In all the embodiments the spacing between the flat base plate in the area
around the
projections and the flat cover plate within a row of projections of the main
filter may be
constant. The spacing may be greater in the region of the end of the row which
is close to the
outlet side of the filter than in the region of the end of the row which is
close to the inlet side
of the filter. This spacing may preferably increase in substantially linear
fashion from one end
of the row of projections to the other.
The facing sides of two adjacent rows of projections define a cohesive chamber
into which
the fluid flows from all the channels between the projections of a first row
and from which the
fluid flows into all the channels between the projections of the adjacent row.
In front of the
first row of projections of the main filter there is a collecting chamber of
oblong cross section
into which the unfiltered or coarsely filtered fluid is conveyed and from
which the fluid flows
into all the channels between the projections of the first row. Behind the
last row of
projections is the filtrate collecting chamber of oblong cross section into
which the fluid from
all the channels of the last row flows and from which the filtered fluid is
discharged.
The projections of the main filter may take the form of posts which are
straight or curved,
viewed in the direction of flow. In addition, the projections may be in the
form of - preferably
straight - columns of any desired cross section, preferably of circular or
polygonal cross
section.
The length of the channels extending between the posts is at least twice as
great as their
height at the entry side for the fluid. The cross section of the channels is
approximately square
or barrel-shaped or trapezoidal; in the latter case the longer side of the
trapezium may be
formed by the cover plate. The channels may for example have a length of 5 to
50 m, a
height of 2.5 to 25 m and a width of 2.5 to 25 m. The width of the channels
may increase
towards the outlet side.
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The spacing between the rows of projections of the main filter is preferably
twice as great as
the width of the channel on the entry side. The rows of projections may run
parallel to one
another or in a meandering pattern or preferably in a zigzag. The rows
arranged in a zigzag
pattern may be inclined relative to one another at an angle of 2 to 25 .
The particles to be filtered out are initially deposited, as a result of the
rows of projections
arranged in a zigzag configuration, in the areas on the fluid inlet side
located close to the
outlet side of the filter, the space between the rows of projections gradually
increases, starting
in the region of the outlet side of the filter. The filter is not completely
blocked and the filter
capacity used up until the inlet space between two rows of projections is
almost entirely filled
with particles to be filtered out.
The degree of separation of the filter is relatively clearly defined owing to
the limited
fluctuations in the dimensions of the channels. The filter does not require
any inflow
distributor for the fluid which is to be filtered or any filtrate collector
for the fluid once it has
been filtered.
The filtered fluid is conveyed in the filtrate collecting chamber to a nozzle.
This preferably
has two openings inclined towards each other. The fluid is thereby divided by
the nozzle into
two streams which are directed towards each other so as to meet behind the
nozzle opening.
In preferred embodiments, first the primary filter structure and then the
secondary structure
are formed inside the nozzle in the direction of flow. The filter structure
extends over the
entire width of the cavity formed inside the nozzle and over a length of
preferably 30 to 70%,
more preferably 40 to 50% of the entire length of the cavity formed inside the
nozzle.
Preferably, the filter structures start immediately after or at the nozzle
inlet. In particularly
preferred embodiments the filter area has two types of filter systems: a
preliminary coarse
filter and a fine main filter. The coarse filter may be made up of a single
row of structural
elements formed in parallel over the width of the chamber. The main filter
preferably has the
zigzag configuration already described. The secondary structure is then formed
in the area
between the end of the filter and the nozzle outlet.
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The nozzle according to the invention may be produced by the methods discussed
above from metal, silicon, glass, ceramics or plastics. The base plate may be
made
of the same material as the cover plate, or a different material. The filter
is suitable
for high pressure operation, e.g. up to 30 MPa (300 bar).
5 In the manufacture of the nozzle according to the invention, in a departure
from the
method known in the art, the underside of the microstructured silicon wafer
firmly
attached to the glass plate is provided with an adhesive film before the
individual
nozzles are formed from the plate.
The microstructured filter nozzle according to the invention is of particular
importance
10 for filtering and atomising a pharmaceutical composition dissolved in a
solvent, in
order to produce an aerosol for administration by inhalation. Suitable
solvents are
water or ethanol or mixtures thereof. Suitable pharmaceutical preparations
include
for example Berotec (fenoterol hydrobromide), Atrovent (ipratropium bromide),
Berodual (ipratropium bromide plus fenoterol hydrobromide), salbutamol (as the
sulphate or free base), Combivent (ipratropium bromide plus salbutamol),
Oxivent,
tiotropium bromide and others.
The present invention may thus comprise not only the nozzles according to the
invention which are described above but also their mass production, the
nozzles thus
produced, as well as inhalers, preferably those of the Respimat type, which
contain
these nozzles and with which medicinally active inhalant formulations can
preferably
be atomised.
The microstructured filter nozzle according to embodiments of the invention
may
have the following advantages in addition to those already mentioned:
- thanks to the large number of channels over a small area it remains
operational even when some of the channels are blocked by contaminants from
the
fluid. This property is critical to the usability of the filter, which is
combined with a
nozzle. When used in an atomiser for dispensing a medicament, failure of the
atomiser within a given usage period may have serious consequences for the
user.
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- The channels are narrowly defined in terms of shape, cross sectional area
and length.
According to one particular embodiment, the dimensions of all the channels
within a
filter are the same.
- The cross section of the channel may be adapted to suit other requirements,
e.g. so as
to fit the cross section of a nozzle downstream thereof.
- A large filtering surface can be accommodated within a small filter volume.
- The flow of the fluid before it enters the channels between the rows
arranged in a
zigzag configuration is substantially directed perpendicularly to the flow in
the
channels.
- The open filter surface (sum of the cross sectional area of all the
channels) is at least
50 % of the total filter surface.
- The filter has a small dead volume, particularly when there is a high
density of built-
in elements.
- The nozzles can be mass-produced in large numbers with low rejection rates.
- Crystallisation or precipitation processes in the pharmaceutical fluid in
the filtrate
collecting chamber are reduced by the built-in elements.
- Finally, the change to the structure of the nozzle according to the
invention has meant
that in mass production the proportion of nozzles which do not exhibit a
permanently
uniform spray pattern has been reduced by roughly a factor of 100, from 0.1-
0.5% to
0.001-0.005%.
The invention will now be explained in more detail with reference to the
drawings.
Fig. 1 shows an embodiment of the filter nozzle, viewed from the side which is
initially
open, which is subsequently covered with the cover plate (not shown). The base
plate
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(1) is microstructured between the edge regions (2a, 2b). The rows (3) of
projections
are arranged in a zigzag; the rows are inclined towards each other by an angle
cc. At
the fluid inlet side in front of the zigzag arrangement there is another row
of
projections (4) which act as prefilters. In front of the projections (4) there
are inlet
slots (5), through which the unfiltered fluid enters the filter. In this
embodiment,
adjacent to the filter there is a nozzle (6) from which the filtered fluid
emerges. The
nozzle is an integral part of the base plate. The space between the filter
rows (3) and
the nozzle (6) is the filtrate collecting chamber. In this, a secondary
structure (50) is
disposed between the base plate and the cover plate. This secondary structure
comprises a large number of built-in elements (51) which extend between these
two
plates. The partial enlargement shown on the right illustrates this state of
affairs. The
spacings between the built-in elements (51) are preferably 0.02 mm from centre
to
centre. Similarly, the diameter of the built-in elements (51) is ideally 0.01
mm.
Fig. 2 shows, on a larger scale, the arrangement of the projections in the
rows (3). The
projections (7) are in this case rectangular posts.
Fig. 3 shows a cross section through a row of projections along the line A-A
in Fig. 2. The
projections (7) have concave curved longitudinal sides between which there are
channels (8) of barrel-shaped cross section.
Fig. 4 shows several embodiments of projections, in each case viewed from the
initially
open side of the filter. The drawing shows a rectangular post (11), an oblong
post
(12) of constant width and rounded short sides, a wing-like post (13), a post
(14) of
constant width and a sloping short side and a post (15) curved in the shape of
a
segment of a circle. The drawing also shows: a square column (16), a
triangular
column (17), a round column (18) and an octagonal column (19).
Fig. 5 shows cross sections through various posts, specifically a rectangular
cross section
(21), a cross section (22) with concave curved longitudinal sides, a
trapezoidal cross
section (23), wherein the long side of the trapezium is connected to the base
plate (1),
a trapezoidal cross section (24) wherein the short side of the trapezium is
connected
to the base plate (1), and a post (25) with two rounded longitudinal edges.
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Fig. 6 shows various arrangements of projections, the projections -
irrespective of their
shape - being indicated by dots of different sizes. The projections may be
arranged in
a matrix (31) or in linear fashion in a row (32) or in a meandering shape (33)
or
zigzag shape (34). A plurality of projections arranged in a row (35), in a
meandering
shape or in a zigzag shape (36) may be arranged in a cascade behind one
another.
Fig. 7 shows the orientation of posts in relation to the direction of inflow
(41) of the fluid.
The posts (42) are arranged parallel to the direction of inflow, the posts
(43) are
arranged perpendicularly to the direction of inflow and the posts (44) are
inclined by
different amounts to the direction of inflow.
Figures 8a/b, which are identical to Figures 6 a/b of WO 97/12687, illustrate
the nebuliser
(Respimat ) with which the aqueous aerosol preparations according to the
invention can
advantageously be inhaled.
Fig. 8a shows a longitudinal section through the atomiser with the spring
biased,
Fig. 8b shows a longitudinal section through the atomiser with the spring
relaxed.
The upper housing part (77) contains the pump housing (78) on the end of which
is mounted
the holder (79) for the atomiser nozzle. In the holder is the nozzle body (80)
and the filter
according to the invention (55). The hollow plunger (57) fixed in the power
takeoff flange
(56) of the locking mechanism projects partially into the cylinder of the pump
housing. At its
end the hollow plunger carries the valve body (58). The hollow plunger is
sealed off by
means of the seal (59). Inside the upper housing part is the stop (60) on
which the power
takeoff flange abuts when the spring is relaxed. On the power takeoff flange
is the stop (61)
on which the power takeoff flange abuts when the spring is biased. After the
biasing of the
spring the locking member (62) moves between the stop (61) and a support (63)
in the upper
housing part. The actuating button (64) is connected to the locking member.
The upper
housing part ends in the mouthpiece (65) and is sealed off by means of the
protective cover
(66) which can be placed thereon.
The spring housing (67) with compression spring (68) is rotatably mounted on
the upper
housing part by means of the snap-in lugs (69) and rotary bearing. The lower
housing part
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(70) is pushed over the spring housing. Inside the spring housing is the
exchangeable storage
container (71) for the fluid (72) which is to be atomised. The storage
container is sealed off
by the stopper (73) through which the hollow plunger projects into the storage
container and
is immersed at its end in the fluid (supply of active substance solution).
A spindle (74) for the mechanical counter is mounted in the covering of the
spring housing.
At the end of the spindle facing the upper housing part is a drive pinion
(75). A slider (76)
sits on the spindle.
An atomiser with which an aerosol is to be produced from a medicament-
containing fluid
contains the nozzle according to the invention which is of similar
construction to the nozzle
shown in Fig. I.
A preferred embodiment will now be described. The numerical values given are
preferred
numerical values inclusive of 20% deviations. A nozzle of this kind has a base
plate 2.6 mm
wide and about 5 mm long. Over a width of about 2 mm it preferably contains 40
rows of
projections arranged in a zigzag. Each row is 1.3 mm long. The projections are
rectangular
posts which are 10 gm long and 2.5 gm wide; they project 5 gm from the base
plate. Between
the posts there are channels which are 5 gm high and 3 gm wide. The built-in
elements of the
secondary structure have a diameter of 0.01 mm. The spacing of the built-in
elements is also
0.01 mm. At the fluid inlet side into the nozzle there is a row of 10
rectangular posts which
are 200 gm long and 50 gm wide; they project 100 gm from the base plate.
Between these
posts are the channels, which are 100 gm high and 150 gm wide. At a spacing of
about 300
gm in front of the row of posts is the inlet slot which is about 22 mm wide
and 100 gm high.
Behind the rows of posts arranged in a zigzag configuration is the filtrate
collecting chamber
which is 5 gm high and gradually narrows from a width of 2 mm and opens into a
nozzle of
rectangular cross section which is 5 gm high and 8 gm wide. This nozzle
opening has been
produced at the same time as the microstructuring of the base plate.
Also shown in Fig. I is the central line 52 which runs through the zigzag-
shaped arrangement
of the rows 3 about halfway between the spike 53 on the inlet side and the
spike 54 on the
outlet side.
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List of reference numerals
1 base plate
2a, 2b edge region
3 row of projections (7)
4 projections (prefilter)
5 inlet slot
6 nozzle
7 projections
8 channel
11, 12, 13, projections (7) in the form of posts
14, 15
16, 17, 18, projections (7) in the form of columns
19
21 rectangular cross section of post
22 cross section of post with concave long sides
23 trapezoidal cross section of post (long side attached)
24 trapezoidal cross section of post (short side attached)
post with rounded longitudinal edges
20 31 matrix-like arrangement of projections (7)
32 linear arrangement of projections (7)
33 meander-shaped arrangement of projections (7)
34 zigzag-shaped arrangement of projections (7)
projections (7) arranged in several rows
25 36 projections (7) arranged in a cascade
41 inlet opening for fluid
42 posts aligned parallel with the inlet opening
43 posts aligned perpendicular to the inlet opening
50 secondary structure
30 50a filtrate collecting chamber
51 built-in elements
52 central line
53 spikes at the inlet side
CA 02530746 2005-12-28
WO 2005/000476 16 PCT/EP2004/006768
54 spikes at the outlet side
55 filter
56 power takeoff flange
57 hollow plunger
58 valve body
59 seal
60 stop
61 stop
62 locking member
63 support
64 actuating button
65 mouthpiece
66 protective cover
67 spring housing
68 compression spring
69 snap-in lugs
70 lower housing part
71 storage container
72 fluid
73 stopper
74 spindle
75 drive pinion
76 slider
77 upper housing part
78 pump housing
79 holder
80 nozzle body
