Note: Descriptions are shown in the official language in which they were submitted.
WO 93/17932 ~ ~ ~ ~ ~ '~ ~ PC'f/EE93/00465
1
A DISPOSABLE CARTRIDGE FOR USE IN MAC~iINES FOR
EXTRACTION AND DISPENSING OF FIOT DRINKS
The present invention relates to a disposable cartridge
comprising a substantially rigid casing which cantains a
portion of powder, granular or like particulate material
for producing a drink by percolation, dissolution or
infusion with hot water under pressure, in which the
casing comprises a cylindrical, substantially hollow body
which includes an imperforate side wall, an inlet end
wall having a perforated central region and a perforated
opposite outlet end wall, and in which the inlet end wall
has an outer peripheral annular rib which surrounds the
perforated region and can be engaged under mechanical
pressure by a heated plate for introducing hot. water
under hydraulic pressure into the cartridge through the
said central region to produce the drink and dispense it
through the outlet end wall.
Cartridges of this general type are known from, among
others, document EP-A-0 057 671.
The peripheral annular rib serves as a kind of seal
cooperating with the delivery outlet plate of the machine
so as peripherally to contain the hot water under
', pressure which is introduced into the cartridge through
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the perforated region of its upper wall from the centre
of the delivery plate.
Given that the pressure of the hot water delivered by the
a delivery plate is of the order of 10-15 bar, it is
desirable that 'the plate should press on the annular rib
and couple with this in a precise manner to prevent hat
water from leaking peripherally before reaching the
interior of the cartridge.
However, it often happens that this coupling is not
perfect due to the fact that the plate and the top of the
rib are not coplanar.
The object of the present invention is to provide a
cartridge of the type discussed above in which a perfect
sealing coupling between the plate and the annular rib
will be guaranteed even in the event that the two parts
are not coplanar.
According to the invention this object is achieved by
means of a cartridge of the type described above,
characterised in that the said annular rib is made from
a plastics material which is softenable at the
temperature to which the water delivery plate is heated.
Preferably the rib has an annular crest which can be
WO 93/i7932 '" PCT/EP93/00465
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flattened under the mechanical pressure of the delivery
plate after softening of the plastics material.
In the preferred embodiment the rib has a frusto-conical
face the vertex of which coincides with the axis of the
cartridge and which has an obtuse vertex angle, as well
as a .radially outer surface forming, with 'the
frusto-conical face, the said flattenable annular crest.
With this arrangement the deformation of the rib under
the effect of the heat accommodates all defects due to
the rib and the plate not being coplanar, thus
guaranteeing a perfect water tight seal under pressure.
In the preferred embodiment the face of the rib has a
very shallow inclination towards the centre of the upper
wall: gradually as the annular crest softens the plate
is able to press on a surface of the rib which rapidly
grows as the plate deSCeTIdS and with a corresponding
rapid reduction in the specific mechanical pressure on
the upper surface of the rib, With this reduction in
specific pressure corresponds a gradually decreasing
softening of the plastics material, and deformation of
the rib is finally stopped without the rib becoming
entirely softened.
The object of the invention ;gill be understood better
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CVO 93/17932 PCT/EP93/O(3d65~.-'.v.
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from a reading of the following detailed description of
a preferred embodiment, given by way non-limitative
example and illustrated in the attached drawings.
In the drawings:
Figure 1 is a perspective view of a cartridge
provided with an annular rib according to the invention;
Figure 2 is a diametral section on an enlarged scale
of the same cartridge;
Figure 3 is a partial section, further enlarged, of
the region enclosed by the circle III in Figure 2; and
Figure 4 is a partial section corresponding to that
of Figure 3 , in which a part of a water delivery plate
pressed on the annular rib is schematically shown, with
the rib having been deformed by the effect of the heat
and the mechanical pressure exerted by the plate.
Referring naw to Figures 1 and 2, a disposable cartridge
comprises a hollow body or casing, generally indicated
10. The hollow body 20 has a substantially cylindrical
form and is able to contain a portion of a granular,
powder or particulate material M (Figure 2) able to
produce a drink by percolation, dissolution or infusion
with hot water under pressure. As far as the machine for
use of the cartridge is concerned, reference is made for
example to document EP-A-0 041 031 which relates to an
automatic coffee machine capable of utilising a cartridge
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~,p 93/17932 PCT/EP93/OOd65
such as that described and illustrated in the attached
drawings.
The hollow body 10 includes a cup-shaped part, generally
indicated 12, and a part constituting a cover, generally
indicated 1,4. Moth the parts 12 and 14 can be made
economically in substantially rigid plastics material
suitable for use with foods. The use of a plastics
material is not however limitative except for the
characteristics which will be described further below.
A convenient material for producing the parts 12 and 14
is a polypropylene wtii.ch, in order to achieve the obj ects
of the invention which will be discussed, has a softening
temperature around 100°C.
The cup-shaped part 12 includes an imperforate
substantially cylindrical side wall 16 which constitutes
the side wall of the casing 10, and a bottom wall 18
which constitutes an outlet end wall of the casing l0.
The bottom wall 18 is surrounded by an annular rib 19
which serves to form a seal on a lower plate or like
element on which~:ne cartridge can be supported by its
lower wall.
The bottom wall 18 is perforated and can have a plurality
of holes, as illustrated for example in document EP-A-0
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041 931, or a single central hole, as described and
illustrated in document EP-A-0 057 671.
The cover 14 includes a perforated circular central
region 20 which constitutes an inlet end wall of the
casing 10. The central region 20 is surrounded outwardly
by a peripheral annular flange 22 coupled to a
corresponding annular flange 24 formed integrally with
the upper edge of the side wall 16 of the cup-shaped part
12.
The central region 20 can have a plurality of holes, as
shown, or other apertures, or one or more peripheral .
holes as in document EP-A-0 057 671 to which reference is
made.
The outer face of the perforated central region 20 of the
cover 14 is surrounded by an outer peripheral annular rib
26 the function of which will now be explained with
reference to Figures 3 and 4.
Referring to Figure 3, the outer peripheral annular rib
26 which surrounds the perforated central region 20 of
the inlet end wall has a frusto-conical face 28 the vertex
of which is coincident with the axis of the cartridge.
The vertex angle of the frusto-conical face 28 is obtuse.
This vertex angle is preferably almost flat, with a value
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of the order of 175°.
The annular rib 26 is delimited by a radially outer
surface 3o which, forms, with the frusto conical face 28,
a circular crest or annular apex 32. Preferably, at
' least in 'the region of the annular apex 32, the front
face 28 and radially outer :Face 30 form between them an
,, angle equal to about 90°.
A preferred material at least for the rib 26 and
preferably for the whole of the body 10 is a food grade
polypropylene having a softening point slightly less than
the temperature of boiling water, but a melting point .
higher than the temperature of boiling water (for example
110°C) .
Tn Figure 4 the reference letter P indicates a metal
plate which forms part of a coffee machine or other
machine for the extraction of a drink starting from the
material M (Figure 2) contained in the cartridge. The
machine can be of the type described and illustrated in
document EP:-A--0 041 031.
The plate P has a central hole for the delivery of hot
water, for example at a temperature of 90°C and at a
pressure between 10 and 15 bar.
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For delivery of hot water under pressure the plate P has
been lowered or otherwise pressed in the direction of the
arrow F onto the annular rib 26. The temperature of the ,
plate P .is substantially equal to that of the hot water,
that is to say of the order of 90°C.
Under the mechanical pressure exerted in the direction of
'the arrow F the plate P has softened and deformed first
the annular apex 32 and then, partially, the upper part
of the rib 26.
In Figure 4 reference numeral 26a represents 'the integral
part of the rib 26 before softening and the reference 26b
indicates the bulge deriving from the softened part 28a
underlying the apex 32. As can be seen, the flat
pressure surface S of the plate P has largely transformed
the initially frusto-conical face 28 into a flat face 28a
which seals against the surface S of the plate P thus
guaranteeing an hermetic seal against the escape of hot
water under pressure from the space, indicated 32, lying
between the perforated central region 20 of the corer 14
and the corresponding central region of the plate P.
The plastics material of the annular rib 26, softened and
deformed under the effect of the heat does not melt due
to the fact that its temperature does not exceed about
100°C which is the temperature of the water introduced
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into the cartridge. It remains in what may be called a
°'rubbery" state and in this state behaves practically as
a resilient seal to the advantage of the sealing effect.
As can be seen in Figure 4, the contact interface between
the plate P and the rib 26, corresponding to the
reference 28a, obtained by the thermal deformation of the
' plastics material of the apex 32 and the remaining part
of the rib 26, occupies a major part of the initially
frusto -conical surface thus guaranteeing a specific
mechanical pressure in the direction of the arrow F such
as not to cause complete softening of the rib 26 which
would give rise to the loss of the sealing effect.
