WO1983000612A1

WO1983000612A1 - Extraction-filtration device, particularly intended for the preparation of coffee

Info

Publication number: WO1983000612A1
Application number: PCT/BE1982/000017
Authority: WO
Inventors: Camille Lejeune
Original assignee: Camille Lejeune
Priority date: 1981-08-18
Filing date: 1982-08-17
Publication date: 1983-03-03
Also published as: IT1152806B; IT8222880A0; EP0086802A1; ES8307518A1; ES515065A0

Abstract

Extraction-filtration device wherein a material to be extracted is contacted with an extraction liquid, whereafter the residue is separated from the liquid by filtration-centrifugation. According to the invention, the filtration is carried out through the joining of a lower conical element (1) and an upper conical element (2) rotatingly driven at 6000 revolutions per minute. The ejection of coffee grounds is done through the opening of the conical elements (1, 2), the grounds being blown towards the outlet of a volute (119) and then into a container provided to this effect. The devices comprises a locking and a system for rising or lowering the casing of the filter which are particularly appropriate.

Description

Extraction-filtration device, intended in particular for the preparation of coffee.

There are many devices intended in particular for the preparation of coffee. A certain number of these machines are more or less automated and allow coffee to be prepared from soluble coffee extracts or powders. It is generally accepted that the coffee thus produced is not very pleasant to drink.

There are also a number of devices which make it possible to prepare coffee from coffee beans which have been more or less fully ground and it is generally accepted that such machines provide better quality coffee. Some of these machines are partially or fully automated, in particular for use in vending machines or for use in the Horeca sector. Most of the known devices are based either on the use of a filter (filter paper, canvas, etc.) or a sieve. Although the quality of the coffee produced is generally satisfactory, there are difficulties due to the presence of residue of marc in the filter or on the sieve. In certain cases, these residues, in particular if they have remained in the machine for a fairly long time, give a disagreeable taste to the coffee which is then prepared.

Also known from patent FR-A-2 236 456 is a method and a device comprising centrifugation. According to this method, a rotating centrifugation enclosure, having a sharp edge at its periphery, is formed by two surfaces of revolution of different respective profiles. The device described comprises a hollow cone having its top turned upwards, applied to a flat lower support, during the rotation of the assembly.

Although it is indicated in this patent that an infusion of coffee is caused in the enclosure, it seems difficult to admit that such an infusion actually occurs because the lower flat support cannot contain liquid and the closing of the enclosure occurs in rotation, which produces a centrifugation and an immediate expulsion of the coffee. In addition, during the expulsion of the coffee grounds, it is projected onto the entire drive mechanism of the centrifuge, which therefore requires regular and costly maintenance of the apparatus.

The present invention aims to provide a device for preparing good quality coffee while avoiding the drawbacks of the state of the art; the device of the invention also has the advantage of allowing very rapid production of ca ^' fé and of being largely auto¬ matisable and in particular of being adaptable to automatic dispensers while allowing a priora¬ infusion coffee, before centrifugation.

The invention therefore relates to a device in which a material to be extracted is brought into contact with an extraction liquid, after which the residue is separated from the liquid by filtration-centrifugation. According to the invention, filtration is carried out through the joint of a lower hollow volume of revolution and an upper obtu¬ ration element, driven in rotation so that rapid filtration is carried out by centrifugation. This procedure allows to introduce into the hollow volume of revolution, a metered amount of coffee or other material to be extracted with the extraction liquid preferably heated and to allow an infusion to take place before or simultaneously with filtration-centrifugation operation.

Other features and advantages of the invention will become apparent. reading the following description, given by way of illustration without limitation of an embodiment of the invention and the claims. It should be noted that this description is made with reference to an extraction-filtration operation intended to prepare coffee but is in no way limited to this use, other applications within the framework of the invention being possible as will be described below. In the drawings:

Figure 1 shows a sectional view of a device according to the invention in the "closed" position, which corresponds to the different stages of coffee preparation; Figure 2 is a view corresponding to that of Figure 1 of the device in the "open" position which corresponds to the position of cleaning and removal of the grounds; Figure 3 shows a detailed sectional view of the locking mechanism of the device; Figure 4 is a section at level IV-IV in the locking mechanism of Figure 3; Figure 5 is a half-section at v-V of the mechanism of the sliding coupling of Figure 3; 6 shows a sectional view corresponding to that of Figure 2, in which the grounds collection device is constituted by a volute and the device for raising and lowering the centrifuge consists of a drive to cams; FIG. 7 represents a section at level VII-VII of the filtration-evacuation assembly of the infusion of FIG. 6; Figure 8 shows a side view of a cam drive mechanism shown in section in Figure 6; FIG. 9 represents a sectional view along line IX-IX of FIG. 8.

Identical reference marks are used for identical or analogous elements shown in the different views.

Referring to Figures 1 and 2, there is essentially a centrifugal filter which is composed of a hollow volume of revolution 1 having the shape of a cone and of an upper closure element 2 also having the shape of 'a cone, the two cones being opposite by their large base. The cone upper 2 carries an inlet strainer and can be lifted by pressing. on the mechanism 4 housed in the drive shaft, so as to pass from the closed position shown in FIG. 1 to the open position shown in Figure 2. Inside the filter, vanes 5 are arranged radially to reduce the inertia of the liquid during startup while allowing a good distribution of the mixture of materials to be centrifuged, namely the mixture of water and ground coffee in the filter. In this way, we are assured of a good static and dynamic balancing during the centrifugation operation.

A peripheral collector 6 is intended to receive the coffee separated by filtration of its marc and it is advantageously heated by a coil 7 connected to the water heater (not shown) of the device in thermo-siphon. This provision also allows immediate availability of very hot water to the solenoid valve 8 controlling the supply of hot water intended for the preparation of coffee.

The device also includes an endless screw 23 connected to a container (not shown) which during the initial impul¬ sion brings a metered quantity of coffee which falls into the funnel 24. The solenoid valve 8 simultaneously allows passage enough hot water to entrain the ground coffee inside the filter. Advantageously, the mixture of coffee and water is allowed to infuse for some time and then, according to the form of execution of the invention, the two conical elements 1 and 2 are made to rotate constituting the essential element of the device d extraction-filtration at a speed of the order of, for example, 6000 revolutions / minute, with a view to centrifugation. By centrifugal force, the ground coffee sticks to the joint of the two cones, the adjustment of which is adjusted so that in centrifugal operation, the spacing of the peripheral lips of the cones is less than the grinding of the coffee. As a result, the coffee extract forcefully crosses the layer

of ground coffee and comes out through the joint of the cones. This coffee is collected by the collector 6 and leaves through the pipe 9.

To cause the ejection of the residue after filtration, a geared motor 10 drives a set of four screws 11 ^* synchronized by a crenellated belt 12. The action of the screws 11 on nuts 13 lowers the assembly constituted by the bearing 14 and the filter element formed by the cones 1 and 2 at a conical recovery chamber 15 intended to receive the grounds. The motor 16 for driving the filter as for the fluid in place and the rotation of the filter continues thanks to the sliding coupling 17. When it is opened, the filter passes from the position shown in FIG. 1 to the position shown in Figure 2. Arrived at the level of the conical recovery chamber 15 for the grounds, the locking mechanism 4 presses against the motor shaft 18 (see Figure 3), thus separating the cones 1 and 2. The descent of the cone 2 being stopped while the cone 1 continues the descent for another 5 mm, for example. Following the separation of the cones 1 and 2, the marc is in turn expelled by centrifugal force and is driven towards the outlet orifice 19 of the recovery cone by scrapers 20 which are driven by the belt 21 and the pulley 22 secured to the screw 11. After a short stop in the open position, sufficient to remove all of the grounds, the assembly constituted by the bearing 14 and the filter 1 and 2 returns to its initial position (position of the figure 1) opposite the collector 6. Advantageously, a baffle 25 is provided to prevent spattering of marc in the collector 6 intended for coffee during the cleaning of the filter intended to remove the marc therefrom at each operating cycle. In operation, at the indicated centrifugation speeds, it is necessary to provide an effective locking mechanism preventing the opening of the two conical elements (1, 2) during centrifugation. According to a particularly preferred embodiment of the invention, the locking device as it is shown in Figure 1 is constituted by a return spring 31 of the upper cone 2 which presses on the rear of the sleeve 32 secured to the rod 33 which by its other end is screwed to the upper cone 2 in order to hold the two cones 1 and 2 in the closed position as shown in FIG. 1.

The threaded part of the rod, at its end on the side of the cone 2, allows the spacing of the cones 1 and 2 to be adjusted. This spacing is given by the compression of the spring 31 resulting from the thrust <to the product to be filtered during the rotation of the two cones. A spring 35 pushes the lock 36 at the end of the sleeve 32. The cylindrical part 37 of the lock 36 wedges 3 balls 38 in the groove 39 against the hardened steel nozzle 40 and prevents the sleeve 32 from sliding.

During the opening phase of the filter by spacing of the cones 1 and 2, a minimum force exerted on the latch 36 by the motor shaft 18 unlocks the assembly when the filter is lowered for the ejection of the grounds. By depressing the latch 36, the conical part 42 thereof allows the three balls 38 to be housed in the sleeve 32 which allows the sliding of this sleeve 32 in the nozzle 40, the compression of the return spring 31 and of this done, the opening of the filter by separation of the cones 1 and 2. This movement is strongly helped by the centrifugal force applying the grounds with a significant force to the joint of the cones 1 and 2.

The rotation of the filter during the ejection of the grounds is transmitted by the sliding coupling 17. Advantageously, according to another embodiment, the ejection of the grounds is carried out through a volute whose base, from the beginning of the spiral , may be steeply sloping towards an exit. In this way, the centrifugal effect of the air sucked through a paddle wheel driven by the drive axis of the two cones, ensures ejection of the marc when said cones open through the volute. Referring to FIGS. 6 and 7, it can be seen that the marc recovery system, namely the marc recovery manifold 15 with scrapers 20, has been replaced by a volute 115, the base of which is horizontal. The pallets 5 inside the filter 1 have been fashioned like blades, as shown in FIGS. 6 and 7.

Pushed back towards the periphery after the opening of the conical elements according to the principle described above and using the centrifugal effect of the air sucked through the strainer 3 by means of the impeller, located in the conical element 1 provided for example from four blades 5, the marc is blown towards the outlet of the volute 119. Then it passes through a nozzle and is ejected, for example in a container provided for this purpose, without contaminating the drive mechanism. The conical elements may also include, at the joint, a lip preventing the backdraft of dry marc from the volute 115 towards the liquid collector 6 disposed above the latter.

Advantageously, the volute 115 is of toroidal shape and has a rectangular section easy to manufacture by stamping. It can however also have the shape of a spiral.

According to the variant of FIGS. 6, 8 and 9, the gearmotor driving the crenellated belt and therefore also the screws (fig.l and 2) can be replaced by a cam mechanism. According to said figures, a bearing 14 slides in a nozzle 125, the fixed upper part being supported by three rigid columns 130. To open the filter, that is to say separate the conical elements 1 and 2 from one other, the gearmotor 10 rotates the crank 126 which controls the articulated rod 127 connected to the pivot provided with a roller 128 secured to the bearing 14. A half turn of the crank 126 lowers the pivot-roller assembly in the groove of helical guidance 129 practiced in the nozzle 125 to the lowest point thereby causing the descent of the bearing 14 and of the conical elements.

WIPO conical elements 1 and 2 and the locking are effec¬ killed according to the same operating mode as that of the embodiment of Figures 1 and 2.

The complete revolution of the crank 126 brings the bearing assembly - conical elements back to the initial position. To prevent the bearing 14 from stalling (in the nozzle 125, a second helical guide groove and a second roller are arranged at 180 °, as also shown in Figure 9. The guide grooves can end at the top and bottom by horizontal parts which keep the bearing 14 fixed relative to the axis while allowing its rotation during the movement of the connecting rod 127. These ends make it possible to mark the stop in the open position to facilitate the ejection of the grounds and ensure locking in the high position.

In order to overcome the inertia of the geared motor 10, it can be provided with a magnetic braking system for example. It can therefore be seen that the control by guide groove and roller 128 has the effect of a control by cam.

It should be noted that the device described can find applications in sectors other than extraction-filtration of coffee. This device can be used for filtration and separation or even washing of all solid materials, the particle size of which must, of course, be chosen so as to be retained at the join¬ ture of the trays while the extracted liquid escapes by this join. Sectors given as an indication for an application of the device of the invention are in particular the chemical industry, the pharmaceutical industry and the food industry.

By way of illustration of possible variants of the mechanism of the invention, mention may be made, for example, of modifications for ejection so as to keep the filter in place, the shaft rising to actuate the ejection mechanism. . In this case, the collector of the recovery chamber must disappear.

It is also possible, of course, to provide numerous alternative embodiments to the locking mechanism, but it must be understood that a sufficiently effective mechanism must be provided because, the effect of the entrifying force on the residue to be separated tends to spread the cones and a locking allowing a rotary movement will be advantageously provided .for a good functioning of the device.

In the example which follows, the invention has been illustrated with reference to the semi-automated production of coffee. Example

After the start pulse (switch, push-button, etc.), the machine starts and the coffee is dosed by worm screw 23 to prepare a cup of coffee; the device has been calibrated to deliver 7 g of coffee which falls into the funnel 24.

At the same time, the solenoid valve 8 allows hot water to pass which carries the coffee inside the filter. The temperature of this water is regulated between 80 and 90 ° C by conventional thermostatic devices. Advantageously, two adjustment buttons are provided either to prepare a "long coffee" in which case, approximately 150 ml of water are supplied, or to prepare a coffee type "espresso" in which case, approximately 100 ml of water are powered. The duration of this operation is of the order of approximately 3 seconds. One can also provide a continuous control by timer, for example, to choose the desired amount of water. Then the screw 23 is stopped, the solenoid valve 8 is closed and for 10 seconds for example, the mixture of ground coffee and water is allowed to infuse. At the end of this time, the filter, namely the plates 1 and 2 are rotated. By centrifugal effect, the coffee which is heavier sticks to the joint of the two cones 1 and 2. The grinding of the coffee must

WIPO of course be chosen so â. that only liquid can be expelled by centrifugal force through the joint of the two cones after passing through the layer of ground coffee. The coffee drops are propelled into the collector 6 and exit through the pipe 9 towards the cup or the cup. The hot water contained in the heating coil 7 prevents cooling of the coffee produced.

The duration of this operation can for example be of the order of 10 seconds.

The next step consists in that the filter descends opposite the conical chamber 5. By action on the mechanism 4, the two filter cones 1 and 2 separate and the marc is ëj.ectëe and brought towards the orifice outlet 19 by scrapers 20, for example-

Then, the assembly goes back up again bringing the two conical plates 1 and 2 in contact (position of closing which brings us back to the start of the cycle). It takes about 6 seconds for this last step which gives a total of about 30 seconds for all operations,

Claims

Claims.

1. Extraction-filtration device in which a material to be extracted is brought into contact with an extraction liquid after which the residue is separated from the liquid by filtration-centrifugation, characterized in that the filtration is carried out through the joining of a lower hollow volume of revolution (1) and an upper sealing element (2), driven in rotation so that rapid filtration is carried out by centrifugation.

2. Device according to claim 1, characterized in that the lower hollow element is a conical element

(1) opposite by the large base to the closure element.

3. Device according to one of the preceding claims, characterized in that the closure element is a conical element (2) opposite by the large base to the lower element of revolution (1).

4. Device according to any one of the preceding claims, characterized in that pallets (5) are arranged radially to reduce the inertia of the liquid during start-up, while allowing good distribution of the mixture of materials to be treated contained in the filtered.

5. Device according to any one of the preceding claims, characterized in that the two filter elements (1,2) are rotated at a speed of the order of 6000 revolutions / minute for centrifugation.

6. Device according to any one of the preceding claims, characterized in that it comprises a locking mechanism intended to prevent the opening of the two filter elements (1,2) during centrifugation, mechanism constituted by a return spring (31) of the upper element (2) which presses on the rear of a sleeve (32) integral with a rod (33) which, by its other end, is screwed to the upper element (2) in order to maintain the two elements (1 and 2) in the closed position, by a spring (35) which pushes a latch (36) to. the end of the sleeve (32), the cylindrical part (37) of the latch (36) wedging three balls (38) in a groove (39) against a hardened steel nozzle (40) preventing the sliding of the sleeve (32), so that a minimum force exerted on the latch (36) can however unlock the part conical (42) of the bolt (36) allowing the three balls

(38) to be housed in this case in the sleeve (32) which allows the sliding of this sleeve (32) in the nozzle

(40), the compression of the return spring (32) and therefore the opening of the filter by separation of the filter elements (1 and 2).

7. Device according to any one of the preceding claims, characterized in that the ejection of the residues after filtration is carried out by separating the two filter elements (1, 2) and by expelling the residue by centrifugal force.

8. Device according to claim 6, characterized in that scrapers (20) entrain said residue towards an outlet orifice (19) of a conical recovery chamber (15).

9. Device according to any one of claims 1 to 7, characterized in that the ejection of the residue after filtration is carried out through a volute (115).

10.A device according to claim 9, characterized in that an impeller formed by the filter ^element ^{^(s)} provided with blades (5) and driven by the drive axis of the two filter elements ensures ejection of the residue after filtration upon opening of said elements through the volute under the centrifugal effect of the aspirated air.

11. Device according to any one of the preceding claims, characterized in that the upward or downward movement of the centrifuge is controlled by a gear motor (10) driving a set of four screws (11) synchronized by a crenellated belt (12), the action of the screws (11) on nuts (13) lowering or mounting the assembly constituted by the bearing (14) t the filter element.

12. Device according to one of claims 1 to

10, characterized in that the movement of raising or lowering of the centrifuge is controlled by a gear motor (10) actuating, by means of a crank (126), an articulated connecting rod (127) connected to the pivot provided with 'A roller (128) integral with the bearing (14), the roller 128 being guided in at least one helical guide groove (129) formed in the fixed nozzle 125 surrounding the bearing (14).

13. Device according to claim 12, characterized in that two helical guide grooves (129) are arranged at 180 ^β C.

14. Application of the device according to any one of claims 1 to 13 to 1 extraction-filtration of coffee by producing a marc containing little moisture.

--FORE