APPARATUS FOR PREPARING AND POURING EXTRACTION BEVERAGES

Abstract: An apparatus for brewing and pouring coffee or tea in unit doses has an upwardly and downwardly moveable extraction chamber (1), a filter unit with exchangeable filter (2), and a collection chamber (3). The collection chamber (5) is covered at the top by a grating (7), which abuts the filter paper, and is closed at the bottom by an impermeable membrane (8), coupled to a displacement mechanism, with which the membrane can be moved up and down. A pouring-out tube (12) is connected to the underside, and it is closed by a valve (21). During a working cycle, in a first phase, hot water and coffee or tea are introduced in extraction chamber (1); in a second phase membrane (8) moves up, by which air is pressed through the filter into the extraction chamber; in a third phase the membrane moves downwardly, by which the extract brewed in the extraction chamber is suctioned through the filter into collection chamber (5); and in a fourth phase the valve is opened and the brewed tea or coffee is poured through tube (12).

Description: APPARATUS FOR PREPARING AND POURING EXTRACTION BEVERAGES The invention relates to an apparatus for preparing and pouring unit doses of extraction beverages such as coffee or tea, comprising a filter unit with means for advancing a strip of filter paper over a fixed filter position, an upwardly and downwardly moveable extraction chamber, located above the filter position, with an at least partly open bottom, and provided at the topside with supply means for supplying doses of extraction agent, such as ground coffee or tea, and hot water, a collection chamber fixedly located under the filter position, of which the open top side, which is covered by a grating or perforated plate, abuts the filter paper on the filter position, and to which a pouring spout, provided with a valve, is connected at the underside, a pressure control means for regulating the air pressure in the collection chamber, and means for driving the various elements in a coordinated way for performing a working cycle, in which in a first phase, during which the bottom edge of the extraction chamber is pressed against the filter position, extraction agent and hot water are introduced in the extraction chamber through the respective feeds, in a second phase air is pressed from the collection chamber through the filter paper into the extraction chamber, in a third phase the brewed extract is suctioned through the filter paper to the collection chamber, and in a fourth phase the valve of the pouring spout is opened, the extrac¬ tion chamber is moved upwards, and the strip of filter paper is advanced. Such apparatuses are known, and are used in particular as automatic coffee or tea vending machines, and are gene¬ rally part of more extensive automatic beverage dispensers, from which other beverages also are available. Such an apparatus is known from several publications, including European patent publication no. 0 483 244. In this known device, the air pressure in the collection chamber is regulated by a driven double-action pump, of which the pump line is connected to the side wall of the collection chamber above the highest level attainable by the extraction flui suctioned into it. There is a fluid outlet at the centre o the bottom of the collection chamber, which serves as pouring spout and which is provided with a valve. In this known device an electronic circuit ensures tha the various elements can work in coordinated fashion. Fo preparing a cup of extraction beverage, e.g. a cup of cof fee, when the extraction chamber is pressed against th filter, and coffee grindings and hot water have been provi ded therein, the pump is switched to blowing, in which ai is blown into the collection chamber, which as a result o the overpressure created penetrates through the filter int the extraction chamber and through this causes an advantage ous mixing action, by which extraction agent (coffee) an hot water contact each other intimately, which allows fo good extraction. After this extraction phase the pump is switched t suctioning, by which as a result of the underpressure crea ted in the collection chamber the extraction fluid is sucti oned from the extraction chamber through the filter into th collection chamber. Finally, the last phase occurs, in whic the valve of the pouring spout is opened and the coffe poured. This known device functions well and purposively fo providing unit doses of extraction beverages such as coffee, but it has the disadvantage that the double-action pump is an expensive element, and further that it is expensive in terms of power consumption. There is further the possibility of the extraction fluid, drawn through the filter during the suctioning phase, being suctioned in part into the pump line when coming down, which entails a risk of damaging the expensive pomp installation. The object of the invention is to provide an apparatus such as described in the pre-characterizing clause, by which the stated disadvantages are avoided. To that end, the apparatus for preparing and pouring unit doses of extraction beverages according to the inventi¬ on is characterized in that the collection chamber has an open bottom, which is sealed by an impermeable, supple membrane, attached fixedly to the bottom edge, and connected at the centre to a displacement mechanism, with which the membrane can be moved upwards and downwards in and out of the collection chamber for regulating the pressure therein. By moving the membrane up and down the necessary underpres¬ sure or overpressure in the collection chamber can, through the resulting increase or decrease in volume of the collec¬ tion chamber, be brought to function such that when the membrane moves up, thus in the collection chamber, air is pressed from the collection chamber through the filter into the extraction chamber, by which the above-mentioned mixing action of the mixture of hot water and extraction agent located in the extraction chamber can occur effectively as a result of the rising air. Conversely, if the membrane moves down or, as the case may be, out of the uptake chamber space then the underpressure created as a result of an increase in volume causes the extraction fluid to be drawn through the filter into the collection chamber in the same way as with the apparatus according to patent publication EP 0 483 244, in order to be finally poured out. There are no particular requirements as regards the membrane. It is only necessary that the membrane is fluid-impermeable and sufficiently strong. It is not necessary for the functioning of the membrane for the membrane to be elastic. Such membranes may be made of suitable plastics materials, such as polyethene, in suitable layer thicknesses. To obtain an action which is as purposive as possible, it is preferable that the collection chamber widens conical- ly in downward direction. This allows for displacement of the membrane upwards or downwards to ensure the largest possible change in volume of the collection chamber, by which the pumping action or suctioning action thereof is improved. According to a practical embodiment of the invention, the membrane is connected at its centre section to a connec¬ ting member, to which the pouring spout is connected. There is also a lever arm connected to this connecting member for an upward or downward movement of the connecting member and membrane. This embodiment entails an appreciable reduction in terms of components, since on the one hand the connecting member provides for the transmission of power from the lever arm to the membrane, and thereby protects the membrane against damage, while on the other hand the pouring function through the pouring spout can take place through it. In this, the embodiment is such that the valve of the pouring member is attached to the underside of the connecting mem- ber, which valve is normally closed and which opens in the lowest position of the connecting member, in which position during operation the extraction fluid is drawn through the filter to the collection chamber. It is noted, that the principle of increase or decrease of the volume for generating underpressure or overpressure in the collection chamber of an apparatus is in itself known from patent publication US 3565641. In this known device the collection chamber is in fact a piston cylinder, in which a pump cylinder is movable to and fro. Here, too, air is pressed through the filter into the extraction chamber by thrusting the cylinder upwards, and underpressure sufficient to be able to draw the extraction fluid from the extraction chamber into the piston cylinder, is generated by moving the piston downwards. When the piston reaches below a certain height during the downward stroke thereof, it passes the opening of a pouring spout, so that the brewed fluid may be poured through it. The piston is further purposively connec¬ ted to a rod which moves to and fro, which —through a crank arm— can perform a complete working cycle. This known device, however, has the disadvantage that the piston needs to fit closely in the cylinder, in order to prevent leaks, as a result of which there is considerable piston wear, resulting in that abrasive particles will come into the beverage to be poured. Furthermore, the drive of the piston is relatively heavy as a result of the relatively close fit, this requiring a relatively high-powered driving engine. In contrast, the invention can be worked with a low power driving engine, and there is no probability at all of contaminating the beverage to be poured as a result of abrasive particles or suchlike. According to a preferred embodiment of the invention the pouring member is formed by a tube of flexible, elastic plastics material, and the valve comprises a clamp roller, connected to a hinge lever biased by a spring, which keeps the clamp roller pressed in a certain position, in which the tube is pinched off, and a bumper edge is provided below the connecting member, against which the free end of the hinge lever in the lowest position of the connecting member, is pressed counter to the spring force, by which the clamp roller releases the tube. In this way the opening and clo- sing of the valve is combined in very simple fashion with the upward and downward movement of the connecting member and membrane, by which a working cycle can be performed during one to-and-fro movement of the connecting member with the membrane, whereby the pouring spout is opened or closed at the right moment. For the required to-and-fro movement the embodiment may be such that the lever arm, connected to the connecting member for an upward and downward movement, is eccentrically coupled to a drive axle, of which a circular stroke co - prises a total working cycle of the apparatus. To this end the lever arm connected to the connecting member may be purposively coupled through a crank rod to the drive axle. In the embodiments described in the foregoing, a layer of flexible material is used for the membrane, which is dimensioned such that it is displaceable upwardly and down¬ wardly at the centre. It is, however, also possible to make use of folding bellows instead of such a simple membrane, which (bellows) folds in and out during the to-and-fro movement and through that provides the required actions. Such folding bellows have the advantage that greater pressu¬ re differences can be achieved, when e.g. larger suction forces are required for suctioning fluid through the filter. The invention will now be described further with refe¬ rence to the drawings, in which: Figure 1 is a cross-sectional view of an embodiment of an apparatus according to the invention, in particular intended for brewing and pouring out coffee in doses, in which the apparatus is shown during a first phase of a working cycle, Figure 2 is a view of the same apparatus during a second phase of the working cycle, Figure 3 is a view of the same apparatus during a third phase of the working cycle, and Figure 4 is a view of the same apparatus during a fourth phase of the working cycle. The apparatus depicted in Figures 1-4 is in particular intended for brewing and pouring out coffee in a dosis quantity, for example a cup. The apparatus has an extraction chamber 1 with means for feeding ground coffee and hot water (indicated schematically) . There is a filter strip 2 of suitable filter paper under the extraction chamber. This filter strip is driven by a drive mechanism, indicated schematically by a drive roller 3 and a counter roller 4, with the filter strip lying inbetween. The extraction cham¬ ber 1 is moveable upwards and downwards by means of suitable raising means (not shown) . There is a collection chamber below the filter strip, indicated generally with reference 5, which has a side wall 6, which widens conically in downward direction, in the shape of an inverted funnel. There is a grating or perfora¬ ted plate 7 at the open top side of this inverted funnel 6, with the filter paper lying above this. The inverted funnel 6 is closed at the bottom by a membrane 8, which is made of flexible plastic and which is impermeable. This membrane is attached on the outside around the lower edge 9 of the inverted funnel 6, and attached at its centre to a connec- ting member 10, which has a thorough connection opening 11 at the centre, in which a plastics discharge tube is inser¬ ted, forming the pouring spout of the apparatus. A screw ring 13, which clamps the membrane, serves to fix the mem¬ brane 8 onto the connecting member 10. The connecting member further has a blind assembly opening, in which a lever arm 15 is assembled. This lever arm 15 is hingedly connected at its bottom end to a crank arm 16, which is fixedly attached to a horizontal drive axle 17 behind a bearing block 18 of this drive axle. The drive axle 17 is driven by a drive motor (not shown) , which can also provide for the driving of the paper strip, and e.g. is coupled to the drive axle 17 by means of a chain transmis¬ sion (not shown) . There is a hinging angle lever 19 attached via a hinge point 20 below the connecting member 19. This angle lever has at its one end, which faces the discharge tube 12, a hinging clamp roller 21 connected to it, which clamps the plastic tube 12 —mounted obliquely in the connecting member 10— by means of the bias of a spring 22 and by this keeps it closed. Further, above the bearing block 18 for the drive axle 17 is an upright rod 23, of which the flanged upper part 24 forms a buffer edge against which the free end of the hinging angle lever 19 is pressed when the closure member goes down, by which the clamp roller 21 comes off the plastic tube 12, so that the latter is opened. When using the apparatus described above, a complete working cycle is performed during one complete rotation of the drive axle, in which a cup or another unit dosis of coffee is brewed and poured out. Successive phases of this working cycle are illustrated in —in succession— Figures 1, 2, 3 and 4. The drive axle 17 rotates during all these phases. In the first phase, illustrated in Figure 4, crank arm 16 is positioned in an obliquely forward position, and extraction chamber 1 is in its lowest position, the bottom edge thereof being pressed against filter strip 2, which in this phase is not driven, above the top edge of the inverted funnel 6, so that the filter is clamped between the bottom edge of extraction chamber 1 and the top edge of collection chamber 5. During this phase coffee and hot water are sup- plied in doses, while crank arm 16 slowly rotates upwards, guided by the continuously rotating drive axle. With that the membrane is pressed upwards in phase 2, illustrated in Figure 2, and air is pressed through filter 2 into the mixture of hot water and ground coffee, by which the mixture undergoes a stirring action that ensures that the coffee is properly brewed. During phase 3, when crank arm 16 has passed its high¬ est position, membrane 8 is pulled down again, creating a suction action that ensures that the hot coffee extract 25 formed in the extraction chamber is drawn through filter 2 and grating 7 into collection chamber 5. During the above- described three phases of the working cycle, the pouring spout —formed by plastic tube 12— is closed, because it is kept pinched by the resilient force of spring 22, which keeps clamp roller 21 pressed against tube 12. Finally, in the fourth phase, illustrated in Figure 4, when further pulling down membrane 8, the lowest position of crank arm 16 is reached, in which closure member 10 has been brought down so low that the free end of hinging angle lever 19 is pressed against buffer edge 24, by which clamp roller 21 comes off plastic tube 21, and opens it, and the coffee extract 25 is poured out through the tube into a cup 26 placed underneath it. At the same time extraction chamber 1 rises and the drive mechanism 3,4 ensures that filter strip 2 is advanced and that the used filter paper is replaced by clean filter paper, ready for use in the following cycle. The invention has been described in the foregoing by way of an example of an embodiment. It will be apparent that the invention is not limited to this sole embodiment, but that numerous variations as regards the construction are possible, all of them operating according to the same prin¬ ciple as the one stated hereinabove. Further, the invention is not limited to coffee alone, but other extraction bevera- ges, too, —e.g. tea or cocoa— may be used. When incorporated in an automatic coffee or beverage dispenser, further usual provisions for sugar, milk, etc. are available. Given the foregoing, all these further aspects will be clear to the skilled person.

Claims: - C L A I M S - 1. Apparatus for preparing and pouring unit doses of extraction beverages such as coffee or tea, comprising a filter unit with means for advancing a strip of filter paper over a fixed filter position, an upwardly and downwardly moveable extraction chamber, located above the filter position, with an at least partly open bottom, and provided at the topside with supply means for supplying doses of extraction agent, such as ground coffee or tea, and hot water, a collection chamber fixedly located under the filter position, of which the open top side, which is covered by a grating or perforated plate, abuts the filter paper on the filter position, and to which a pouring spout, provided with a valve, is connected at the underside, a pressure control means for regulating the air pressu¬ re in the collection chamber, and means for driving the various elements in a coordinated way for performing a working cycle, in which in a first phase, during which the bottom edge of the extraction cham¬ ber is pressed against the filter position, extraction agent and hot water are introduced in the extraction chamber through the respective feeds, in a second phase air is pressed from the collection chamber through the filter paper into the extraction cham¬ ber, in a third phase the brewed extract is suctioned through the filter paper to the collection chamber, and in a fourth phase the valve of the pouring spout is opened, the extraction chamber is moved upwards, and the strip of filter paper is advanced, characterized in that the collection chamber has an open bottom, which is sealed by an impermeable, supple membrane, attached fixedly to the bottom edge, and connected at the centre to a displa¬ cement mechanism, with which the membrane can be moved upwards and downwards in and out of the collection chamber for regulating the pressure therein. 2. Apparatus according to Claim 1, characterized in that the collection chamber widens conically in downward direction. 3. Apparatus according to Claim 1 or 2, characterized in that the membrane is connected at its centre section to a connecting member, to which the pouring spout is connected, there also being a lever arm connected to this connecting member for an upward or downward movement of the connecting member and membrane. 4. Apparatus according to Claim 3, characterized in that the valve of the pouring member is attached to the underside of the connecting member, which valve is normally closed and which opens in the lowest position of the connec¬ ting member. 5. Apparatus according to Claim 4, characterized in that the pouring member is formed by a tube of flexible, elastic plastics material, and that the valve comprises a clamp roller, connected to a hinge lever biased by a spring, which keeps the clamp roller pressed in a certain position, in which the tube is pinched off, and a bumper edge is provided below the connecting member, against which the free end of the hinge lever in the lowest position of the connecting member, is pressed counter to the spring force, by which the clamp roller releases the tube. 6. Apparatus according to any of Claims 3-5, characterized in that the lever arm, connected to the connecting member for an upward and downward movement, is eccentrically coupled to a drive axle, of which a circular stroke comprises a total working cycle of the apparatus. 7. Apparatus according to Claim 6, characterized in that the lever arm connected to the connecting member is coupled through a crank rod to the drive axle. 8. Apparatus according to Claim 6, characterized in that the membrane is formed by a folding bellows. — « — » —

Inventors: VERHOEF KEES, VERHOEF, KEES
Applicants: VERHOEF KEES, VEROMATIC INT BV, VERHOEF, KEES, VEROMATIC INTERNATIONAL B.V.
Application year: 1995
Main classification: A47J31
IPC codes: A47J31