Europaisches Patentamt
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European Patent Office
Office europeen des brevets
0 682
ation and mention
(45) Date of publication
of the grant of the patent:
13.01.1999 Bulletin 1999/02
(51) |nt. CI.6: A47J 3 1 / 0 6
(21) Application number: 94670006.9
(22) Date of filing: 19.10.1994
(54) Back-pressure filter, to prepare cream coffee
Gegen-DrLick Filter, zum Bereiten von Kaffee Creme
Filtre a pression opposee, destine a preparer du cafe creme
(72) Inventor:
Marques Ribeiro, Valdemar,
Estrada Exterior da
P-4450 Matosinhos (PT)
(84) Designated Contracting States:
(30) Priority: 11.03.1994 PT 898794
(43) Date of publication of application:
22.11.1995 Bulletin 1995/47
(73) Proprietor:
Custio, Matosinhos (PT)
(74) Representative:
Sousa da Silva Lourenco, Ludgero
A TECNAL-Gabinete de Registos Limitada,
Avenida Antonio Augusto de Aguiar,
80 r/c Esq.
1000 Lisboa (PT)
(56) References cited:
EP-A- 0 264 352
DE-A-4 129 814
EP-A- 0 459 323
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give
notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in
a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art.
99(1) European Patent Convention).
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EP 0 682 902 B1
The present invention relates to a novel back-pressure filter, to be inserted in a standard filter support of
pressurised water coffee machines for preparing cream
coffee, independently from the grinding degree to which
the coffee beans were formerly submitted.
There are several filters already known for coffee
machines, from the simple bases (more common) to the
double ones and those using a rubber ring with or without, a flat bar or helicoidal springs, all of them with the
purpose of retaining the pressure, but so far the results
obtained have not been too brilliant, because when the
grinding degree is low, the known filters let the water
pass quickly through the coffee without the consequent
cream effect.
From German Patent DE-A-41 2981 4, that relates to
a filter according to the preamble of claim 1, it is known
to use a spherical calotte shapped rubber ring, with a
cilindrical hole in the middle, which is placed between
the bottom part of a classic filter insert and the innermost bottom part of the filter support. This means that
this filter support can be used without the spherical
calotte rubber ring, thus only with the classic filter insert,
because they are separated parts.
From EP 459323, another filter is known, that
includes a classic filter insert in a filter support and
between these is placed a plate sealed against the inner
walls of the filter support by means of a ring, and
whereby the cream coffee is formed thanks to the flexible action of a flat spring bar, which closes more or less
a relative bore in said plate, all these parts being independent of the classic filter insert.
Those filters using rubber rings, or other peripheral
parts, do it simply by depositing it on the bottom of the
filter body, what provokes, very often, its fall into the
container of coffee mass already used or even to the
floor with the consequent disadvantages. Those with
rubber, have it fixed (or just placed on) to the filter support.
The present description refers a novel filter to coffee-machines, that proposes a back-pressure filter
according to claim 1.
Observing the annexed figures where, without any
limitative character, one can see a preferred way of construction of the present invention, which will be
described as follows:
Fig. 1 Fig. 2 -
The filter with its composing parts, by order
of fitting inside the filter body, with the rubber ring in cross-section along a diameter:
An exploded view in cross-section of the
encircled part of Fig. 1;
The described filter consists mainly in a filter body
(1) a silicone rubber ring (2) and a bored disk (3 ) with
very small holes, in a circular area of diameter roughly
limited by the straight lines "A" and "B".
The filter body (1) present an adequated external
shape as well as dimensions, in order to be used in any
common filter support, in the place of well known single
The filter body (1) has a general cilindrical form presenting in its bottom face one outlet (14) made in a portion that projects out wardly in such way that arises a
certain free volume (13), having a concentric circular
groove (7) and protrusion (8), to receive the rubber ring
The said rubber ring (2) has a circular and plan
shape in rest position characterized to have on its upper
surface a central hole (4) communicating with a coaxial
recess (5) in its bottom of a larger than hole (4).
The bottom side of said rubber ring (2) further comprises a concentric and peripheral circular protrusion (6)
which will be fitted into a circular groove (7) of the filter
body (1) and set upon the inner circular protrusion (8) of
the base or bottom side of the said filter body (1), which
provide, to keep it in position, when its flexible central
zone is deformed under pressure.
On the ring (2) positioned as above described, the
bored disk (3) compresses the ring (2) to the innermost
part of the body (1) and is thus retained in the inside of
the filter body, which will be later used in the filter supports of coffee machines.
The bored disk (3) constituted by a metallic plan
plate presents a little and peripheral edge (11) rising up,
to increase its mechanical resistance, and is pre-bored
by a very small holes, arranged in a circular area around
its centre, with a diameter between "A" and "B".
During the filter fitting, the machine, that presses
down the bored disk (3), against the rubber ring (2), produces around the outside of the filter body (1) one slight
groove (9) which gives rise to a protrusion (1 0) on the
innerside, which will fix peripherally and definitively the
said disk (3) on its edge (11). So, all the constitutents
parts of the present filter, remain as one piece.
The operation will be as follows, that is to say, as
soon as the "filter" object of present description is put
inside a common filter support of a coffee machine
(under-pressure), and previously ground coffee is put, in
the container part (12) of the filter body (1) and the filter
support is applied to respective machine.
When the hot water under-pressure is turned on, it
tends to pass through the ground coffee, but the detail
of the rubber ring (2), which only has one little passage
hole (4) and consequently lesser flowing capacity than
the bored disk (3), the pressure forces the ring (2), duly
fixed in its periphery (6,7,8), to deform itself, due to its
intrincical elasticity, and it creates a back-pressure, that
when deformed can occupy the free volume (13) immediately below, in the lower part of the filter body (1).
The coffee remaining, momentarily, in the area
between the said disk (3) and the said ring (2) and passing through the central hole (4) of the ring (2), which
presents little notches on the upper and lower sides,
creates foam which increases, when the pressure
EP 0 682
682 902
)2 B1
decreases in the lower recess (5), even before said coffee passes through the outlet (14) to the cup(s) where it
collects, giving rise to cream coffee.
1. Back-pressure filter to be inserted in a standard filter support of a pressure coffee machine for preparing cream coffee comprising a cylindrical body (1)
presenting a bottom face characterised in that the 10
bottom face of said body (1) comprises a central
outlet (14) projecting outwardly and a concentric
circular groove (7) surrounding said outlet (14), in
that the filter further comprises a rubber ring (2)
presenting on its upper surface a central hole (4) 15
communicating with a coaxial recess (5) in its bottom surface of a larger diameter than said hole (4),
the bottom surface of said rubber ring (2) further
comprising a concentric circular protusion (6) to fit
into the circular groove (7) of said body (1) so as to 20
retain the rubber ring (2) inside the body (1), and a
bored disc (3) provided with holes arranged in a circular area around its centre, the bored disc (3)
being peripherally fixed in the filter body (1) on top
of the rubber ring (2) by means of a circular protu- 25
sion (10) on the inner side wall of said filter body
1. Einer Gegendruck-Filter dass in einen ublich Filtergestell von eine Kaffeemachenddruck-Maschine fur
die einen Sahne-Kaffee Vorbereitung angeordnet
ist und dass einer zylindrischer Korper (1) mit einen
Unterflach, dadurch gekennzeichnet, dass das
Unterflach von bettrefend Korper (1) einen zentral
Ausgang (14) nach aussen erstreckend und einer
konzentrisch kreisformiger Nut (7) dass den daruber erwhanten Ausgang 14 umgibt aufweist, dass
der Filter einen Gummi-Ring (2) der am seines
Uberflasch einen Zentral-Borung (4) aufweist welches in Verbindung mit eine koaxiale Vertiefung (5)
in seiner Unterflach ist und dass einen grosser
Durchmesser auweist dann dariiber erwhant
Borung (4), das Underflach von bettrefend GummiRing (2) enthaltend noch einen kreisformiger Vorsprung (6) zum einfiigung im kreisformiger Nut (7)
vom dariiber erwhante Korper (1) urn dem GummiRing (2) innerhalb des Korpers (1) zu festhalten,
und einen Durchgebohrt-Scheibe (3) mit in einer
kreisformiger Bereich seiner Zenter umgebend
angeordneten Lochern versehen, und der Durchgebohrt-Scheibe (3) befestigt zu dein Filters Korper
(1) oberhalb dem Gummi-Ting (2) einer kreisformiger Vorsprung (10) an den Innenseite-Wand von
bettrefend Filter Korper (1).
Filtre de contre-pression pour insertion dans un
support de filtre standard d'une machine de cafe a
pression pour la preparation de cafe creme, constitue par un corps cilindrique (1) lequel presente une
face de fond characterisee parce que la dite face de
fond du corps (1) comprend un trou central de sortie (14) qui se projecte vers I'exterieur et une rainure annulaire concentrique (7) entourant le susdit
passage (14), le filtre comprend en outre un
anneau en cautchouc (2) lequel presente sur la surface superieure un trou central (4) communiquant
avec un evidement coaxial (5) sur sa surface inferieure d'un diametre plus grand que celui du susdit
trou (4), comprenant en outre la surface inferieure
du susdit anneau de cautchouc (2) une projection
circulaire concentrique (6) pour raccordement dans
la rainure circulaire (7) du susdit corps (1) de fagon
a retenir I'anneau de cautchouc (2) dans I'interieur
du corps (1), et un disque forete (3) equipe de trous
disposes periferiquement fixes sur le corps du filtre
(1) sus I'anneau de cautchouc (2) par intermise
d'une projection circulaire (10) de la paroi laterale
du susdit corps de filtre (1).
EP 0 682 902 B1
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