EP0000685B1 - Automatic infusion machine for preparing coffee and similar beverages - Google Patents

Description

The present invention relates to an automatic device for brewing espresso or other similar drinks in which a drawer. arranged above a cylinder can occupy two positions, the drawer having a bore for admission of the grinding dose passing through the thickness of the drawer and can be arranged in a position coaxially with the cylinder, a piston being slidably mounted in this latest.

There are already fully automatic coffee machines, tokens, coins or counter, but they pose maintenance problems due to their complexity.

They require either planetary or worm geared motors for positioning, or hydraulic oil power stations, the slightest leak of which gives off an unpleasant odor in the establishment.

There is also another problem which has hitherto been unsolved or poorly resolved, that of tamping down the dose of ground coffee to form a cake on the filter.

Indeed, the packing pressure is very high, too low the hot water which is sent to the filter for the infusion of coffee progresses in swirls in the cake, creates favored paths (chimneys) and only soaks part of the ground coffee cannot completely extract the aromatic elements from the coffee; too strong: the water, meeting a very compact mass, hardly drips through, punctures the cake creating a chimney, infuses only part of the amount of coffee and gives poor coffee; and, in extreme cases, the water not being able to pass through the wafer, the machine stops.

In addition, in the different types of automatic machines, several different operations are provided for, in which successively are carried out: reception of the milling dose, packing to form a cake, infusion, expulsion of the used cake, cleaning the filter ... or in some designs, after the infusion, the spent cake remains on the filter until the next cycle which can take place several hours later, with all the drawbacks that result ...

In other designs, it is necessary to use dosages of ground coffee to form the support of the pancake which will be infused, doses of ground coffee which will be discharged without being used for making coffee.

The continuation of these various operations requires mechanisms, complex transmissions, hydraulic, electrical, mechanical, resulting in significant dead times (sometimes 10 seconds per infusion cycle).

Various embodiments using a drawer, for example the patent FR-A-2 119113 include an infusion piston which must leave its cylinder, pass through the drawer and return to an opposite cylinder. This kind of mounting is not possible on quality material; the life of the seals is not sufficient.

The present invention is characterized in that, in the position of rest of the drawer, the bore which passes through it is coaxial with the cylinder for the admission of the grinding dose on the piston in the low position. The drawer then moves into the working position, the brewing chamber arranged on its underside becomes coaxial with the piston which moves at this time in the high position. When its upper surface is flush with the lower surface of the drawer, hot water is injected into the brewing chamber.

The piston remains in this position during the infusion and the return of the drawer to its rest position, the latter takes away the ejected marc cake, the piston returns to its low position to allow the start of a new cycle.

The brewing chamber is supplied from the bottom up which allows better extraction of the coffee aromas, but could also be done conventionally from top to bottom in another embodiment not shown.

. The marc is ejected by removing the spent coffee grounds from the mold by washing the brewing chamber against the current; but could also be done, in an embodiment not shown so as to evacuate dry, spent coffee grounds pancakes.

The drawer playing the role of distributor: infusion inlet, outlet of the brewed coffee, release of the water evacuation of spent marc; the sealing surfaces which are applied to it also serve as guiding in translation.

Another typical problem with the process according to FR-A-2 119 113 is that it requires too many solenoid valves (5 in the case of the patent cited above) which are necessary for the displacement of the piston cylinder and of the intake hot water.

The successive control of these solenoid valves requires either a series of microswitches actuated one after the other, or a programmer which has the disadvantage of slowing down the mechanism since it is necessary to allow times greater than the various movements so as not to risk the hazard.

• Le piston d'infusion parcourt une faible course dans son cylindre et ne sort pas, deux électrovannes fonctionnant à l'eau froide suffisent à l'ensemble du cycle, la distribution de l'eau chaude d'infusion est réalisée par le tiroir et un clapet largement dimensionné moins sensible au calcaire qu'une électrovanne.

These problems are solved in the present invention:

• The infusion piston travels a short stroke in its cylinder and does not come out, two solenoid valves operating with cold water are sufficient for the whole cycle, the hot infusion water is dispensed by the drawer and a widely dimensioned valve less sensitive to lime than a solenoid valve.

A single microswitch is sufficient for the operation of the device and is used only to detect mine when the mechanism is in the rest position.

• Des organes moteurs pour déplacer la pièce où se trouve la chambre d'infusion, un vérin dans le cas du toiroir ou tout autre système d'avance dans le cas d'un autre mouvement.

Other devices of known types complete the group:

• Motor organs for moving the room where the brewing chamber is located, a jack in the case of the roofing rack or any other advance system in the case of another movement.

A double piston device, up and down, for the grinding receiving device, for forming and holding the pancake during the infusion.

Water dosing and coffee grinding devices are also part of the accessories necessary for fully automatic operation of the group.

The simplicity of the reciprocating movements by jack, not requiring end stops or positioning, provides very rapid maneuvering (less than 3 seconds per infusion cycle).

On the other hand, the jack controlled by two solenoid valves and the drawer itself serving as a hydraulic distributor makes it possible to simplify the hydraulic circuit and the electrical diagram; moreover, this design eliminates the use of solenoid valves on the hot water circuit, a source of scaling and breakdowns typical of this kind of machine.

The main advantage of the present invention consists in a rational realization of the various organs, without complex mechanism, which reduces the risk of incidents, moreover no trace of spent coffee grounds remains in the brewing chamber, nor on the filter, nor on the tamping piston, excluding any changes in taste and unpleasant odors.

• La fig. 1 est une coupe schématique d'un groupe automatique conforme à la présente invention, en position repos,
• La fig. 2 est une figure analogue à la fig. 1 mais en position travail.
• La fig. 3 est une vue de dessus, le couvercle 6 ôté, tiroir 7 en position repos avec des écorchés montrant la disposition des différents distributeurs prévus pour le passage de l'eau chaude d'infusion, de sortie du café infusé et d'eau d'évacuation du marc de café épuisé.
• La fig. 4 est identique à la fig. 3, mais le tiroir est en position travail.
• La fig. 5 est une figure schématique du corps seul indiquant les différents emplacements des distributeurs A, B, C, D, du robinet de décompression E et du clapet non retour 27.
• La fig. 6 est une vue de dessus de la fig. 5.
• La fig. 7 est une coupe brisée de la fig. 6 suivant les axes 0, P, montrant la disposition du clapet non retour 27 et du robinet de décompression E et la fixation de l'obturateur 18, toutes. les pièces étant en place sur le corps.
• La fig. 8 montre schématiquement le circuit hydraulique 10 sur lequel on distingue:
  • a-pompe de type connu
  • b et c-électrovanne à 3 voies de type connu
  • d-électrovanne à 2 voies de type connu
  • e-un verre doseur d'eau électronique de type connu
  • f-une chaudière à échangeur de température de type connu, sur laquelle est directement fixé le corps 1
  • g-un clapet non retour de type connu.

Other objectives and advantages of the present invention will emerge more fully from the following detailed description which relates to a preferred but not exclusive embodiment and which refers to the appended figures in which:

• Fig. 1 is a schematic section of an automatic group according to the present invention, in the rest position,
• Fig. 2 is a figure similar to FIG. 1 but in working position.
• Fig. 3 is a top view, the cover 6 removed, drawer 7 in the rest position with cut-away showing the arrangement of the various distributors provided for the passage of hot brewing water, outlet of the brewed coffee and water evacuation of spent coffee grounds.
• Fig. 4 is identical to FIG. 3, but the drawer is in the working position.
• Fig. 5 is a schematic figure of the body alone indicating the different locations of the distributors A, B, C, D, of the decompression valve E and of the non-return valve 27.
• Fig. 6 is a top view of FIG. 5.
• Fig. 7 is a broken section of FIG. 6 along the axes 0, P, showing the arrangement of the non-return valve 27 and the pressure relief valve E and the fixing of the shutter 18, all. the parts being in place on the body.
• Fig. 8 schematically shows the hydraulic circuit 10 on which there are:
  • a pump of known type
  • b and c 3-way solenoid valve of known type
  • 2-way solenoid valve of known type
  • e-a known type of electronic water measuring cup
  • f-a boiler with known type temperature exchanger, on which the body 1 is directly fixed
  • g-a non-return valve of known type.

We see in fig. 1 and 2 that the group consists of the body in which a cylinder is arranged which receives a cylinder 3 forming the hollow piston; inside this cylinder slides a piston 4.

Parallel to the axis of the piston 4 and to the left in figs. 1 and 2, there is a funnel 5 which receives the spent coffee grounds to direct it towards the evacuation, the emptying.

A cover 6 closes the top of the body and provides a housing in which a drawer 7 slides; the drawer 7 carries a bore 8 which in the rest position fig. 1 is coaxial with the piston 4. On the underside of the drawer 7 is machined a recess 9 of frustoconical shape, large base downwards, a filter 10 is fixed at a certain distance from the bottom of this recess 9 so as to form a bedroom 1 1; in the working position this recess is coaxial with the piston 4.

The drawer 7 receives its translational movement by a hydraulic cylinder of known type with double effect 12 connected to the drawer 7 by the rod 13 and the axis 14.

The piston 4 is fixed to a rod 15 which carries a piston 16 at its lower end.

The piston 1 6 slides in a cylinder 17 arranged in the lower part of a shutter 18 closing the cylinder 2.

The shutter 18 is fixed to the body 1 by the screws 19 fig. 6; it also maintains in position a spacer 20.

A valve 21 is housed in a chamber 20a of the spacer 20; inside this valve 21 slides the rod 15 of the piston 4; by means of a spring 22, the valve 21 presses tightly on a flat seal 23.

It is between a flat seal 24 located on the upper edge of the cylinder 3 and a flat seal 25 fixed under the cover 6 around a bore 26 coaxial with the cylinder 3, that slides the drawer 7.

• En A-distributeur en communication directe avec une chaudière de type connu à échangeur de température.
• en B-distributeur éjection marc et remise au point mort.
• en C-distributeur d'entrée eau pour la montée du piston en position infusion (fig. 4 tiroir en position travail).
• En D-Distributeur sortie café infusé. Le rôle de ces différents distributeurs sera expliqué plus en détail au cours de l'exposé ci-après:
  • L'eau de la chaudière f étant à la tem- perature idéale: par un contact électrique de type connu, on fait tomber une dose de café moulu délivrée par un système connu en soi, à l'intérieur du cylindre 3 au travers des alésages 26 et 8 respectivement du couvercle 6 et du tiroir 7; le même contact électrique a excité l'électrovanne qui délivre au verre doseur e une quantité d'eau électroniquement dosée par un système connu. Cette quantité obtenue l'électrovanne d est coupée, la pompe a est mise sous tension de même que l'électrovanne à 3 voies c.

Figures 3 and 4 show the different distributors:

• In A-distributor in direct communication with a boiler of known type with temperature exchanger.
• in B-marc ejection distributor and return to neutral.
• in C-water inlet distributor for mounting the piston in the infusion position (fig. 4 drawer in the working position).
• In D-Dispenser brewed coffee outlet. The role of these different distributors will be explained in more detail during the presentation below:
  • The water in the boiler f being at the ideal temperature: by an electrical contact of known type, a dose of ground coffee delivered by a system known per se is dropped inside the cylinder 3 through the bores 26 and 8 respectively of the cover 6 and of the drawer 7; the same electrical contact has excited the solenoid valve which delivers a quantity of water electronically dosed to a metering glass by a known system. This quantity obtained the solenoid valve d is cut, the pump a is energized as well as the 3-way solenoid valve c.

The pressurized water delivered by the pump, drawn from the dosing glass e reaches the jack 12 at 12a and through the non-return valve g to the temperature exchanger f.

In the rest position of the drawer 7 fig. 3 the water coming from the exchanger cannot flow, the distributor A being closed by 1 the drawer 7. The water arrives at the jack 12 at 12a and pushes the drawer 7 to the right in the working position.

The water contained in the jack, on the opposite face of its piston exits at 12 b, passes through the solenoid valve b which, without voltage passing through in the direction of the arrow bb and is sucked by the pump a.

At the end of travel stop, the jack 12 pushed the slide 7 into the working position; the differential section duct hh then puts the distributor A of the exchanger f into communication with the distributor C fig. 4.

The pressurized water from distributor C descends into a conduit i fig. 5, 6 which brings it into an annular groove i 'fig. 5 and 6 of the non-return valve 27, by the conduit i "to the annular groove j fig. 7 and by the conduits j 'fig. 7 from the spacer 20 to the housing 20a of the valve 21 held in a sealed manner on the joint 23 by spring 22.

The pressurized water having no outlet on this side there pushes up a ball 28 of the non-return valve 27 passing in this direction and penetrates by a conduit K in an annular space L formed by the chamfer of the lower inner edge of the cylinder 3. The lower front wall of the cylinder is pierced with holes 29.

Under the action of the water pressure, the upper edge of the cylinder 3 comes to bear in a sealed manner by means of a seal 24 around the recess 9 FIG. 2, placed in the working position coaxially with the cylinder 3. Through the holes 29 the water penetrates inside the cylinder 3 and pushes the piston 4; the latter going up causes the rod 15 the piston 16 which is integral with it. In its movement, the piston 16 drives out the water contained in the cylinder 17 by conduits M opening into a circular groove N, a nipple 30 directing the water through. through the solenoid valve C, de-energized, passing in the direction of the arrow aa towards the pump a.

In its upward movement and at the end of the stroke, when the piston 4 is flush with the lower base of the drawer 7, after having compacted the amount of ground coffee in the recess 9, the rod 15, by a shoulder 31, drives the valve 21 thus delivering switching to pressurized hot water. The latter, coming from the exchanger and under the pressure of the pump, passes through conduits o 'o "to a cavity 32 of the piston 4 and through a diffusion grid 33 which covers it allowing the coffee infusion. The coffee will flow into the cup through a pipe P opening into the chamber 11, above the filter 10 of the recess 9, come in concordance, drawer in working position fig. 4, with the dispenser D and its conduit 34.

When the quantity of selected water contained in the measuring cup e, is completely sucked by the pump, a known electrical circuit interrupts the arrival of the current to the solenoid valve c and energizes the solenoid valve b.

The pump continuing to operate, the pressurized water arrives at the jack 12 at 12b and pushes it to the left, to bring the drawer 7 to the rest position fig. 4; the water contained in the jack is sucked by the pump through the solenoid valve C, de-energized, passing in the direction of the arrow aa fig. 8; the pump also discharges through the nipple 30 fig. 7 in the annular groove N and the conduits M in the cylinder 17 fig. 7; but the presence of the non-return valve 27 fig. 7 opposing the passage of the water contained in the chamber 35 fig. 4 formed in the cylinder 3 under the piston 4; the piston 4 is therefore kept in the high position fig. 2. Consequently, the piston 16 secured to the piston 4 by the rod 15 of the piston 16 cannot descend.

The water drainage from the chamber 35 fig. 4 will be through the duct r leading to the distributor B. fig. 4 when the drawer 7 has reached the rest position will bring the conduit P of the recess 9 into line with the said distributor B FIG. 4.

In its downward movement, the piston 16 fig. 2 will drive the piston 4 in the low position.

This design allows the drawer 7 since the piston 4 is flush in this position fig. 2 its underside, to entrain the whole of the spent coffee cake being in the recess 9.

The drawer 7 which has reached the rest position fig. 3, the water contained in room 35 fi ^g . 2 is evacuated through the conduit K fig. 5, 6 and 7, by the conduit r having its origin in the chamber 28a above the ball 28 of the non-return valve 27 which opens in "r '" in the distributor B, from there by the conduit P which ends in the chamber 11 above the filter 10 of the recess 9; this water expels all of the spent coffee grounds in the funnel 5 fig. 1 and wash the filter 10 against the current.

The piston 16 arriving at the full stroke meets the lever 36a controlling the microswitch 36 which stops the pump. The tap E gives the option of evacuating through the pipe S, when acting on it, in the event of a grinding dosage error, the water contained in the chamber 35 fig. 2 authorizing the return of the drawer 7 to the rest position and the start of a new cycle.

Sealing surfaces 38, 39, 40 and 41 with low friction are disposed respectively in line with the distributors A, B, C and D; pressing against the drawer 7 they also serve as a guide for its transverse movement.

Claims (9)

1. Automatic device for the infusion of expresso coffee or other similar beverages in which a drawer (7) places above a cylinder (3) can hold two positions, the drawer (7) having an opening (8) for the measure of grinding coffee which goes through the depth of the drawer (7) and can be placed in a position co-axial with the cylinder (3), a piston (4) sliding into the latter when raised. It is characterised by:

- A reception chamber for the measure of grinding coffee is delimited by the interior lateral surface of the cylinder (3) and the upper surface of the piston (4) in lower position, the drawer being in rest position in which the opening (8) is co-axial with the cylinder (3), thus allowing the introduction of the measure of grinding coffee into the aforementioned receptior chamber.

An infusion chamber is delimited by a blind hole (9) placed on the lower surface of the drawer (7) and the frontal upper side of the piston (4) in upper position, the drawer (7) being in work position, position in which the blind hole (9) caps the cylinder (3 and is co- axial with this latter, the frontal surface of the piston (4) touching the lower surface of the drawer (7) the water being injected into the infusion chamber, the piston (4) staying in this upper position during the infusion off and ejecting the cake of used grounds, the piston (4) returning to its lower position so that a new cycle can begin.

2. Automatic device for the infusion of beverages in accordance with Claim (1) in that the water is fed into the infusion chamber from the bottom towards the top through a diffusion grid (33) placed on a piston (4).

3. Automatic device for the infusion of beverages in accordance with (Claim 2) in that the cylinder (3) forms a hollow piston, its upper frontal surface having a watertight gasket applied by the hydraulic pressure of infusion against the drawer (7) only during infusion.

4. Automatic device for the infusion of beverages in accordance with Claim (1 to 3) in that, in work position, the drawer (7) bored by a pipe (h, h') ensures connection with distributors (A) and (C), the distribution of hot water for infusion of the coffee, a pipe (P) ensuring together with the distributor (D) the distribution of beverage infused and in that in rest position, the pipe (P) in connection with the distributor (B) ensures distribution of water for the ejection of the used grounds and for cleaning the filter (10) and infusion chamber.

5. Automatic device for the infusion of beverages in accordance with one of the Claims (1 to 4) in that the hollow (9) is shaped like a truncated cone.

6. Automatic device for the infusion of beverages in accordance with one of the Claims (1 to 5) in that the low friction watertight bearings (38, 39, 40, 41) are placed straight to the distributors (A, B, C, D), maintained on the drawer (7) and serving as guides for its transversal movement.

7. Automatic device for the infusion of beverages in accordance with one of the Claims (1 to 6) in that a valve (21) permitting entry of water for the infusion is opened by the piston (4) at the end of its upward movement.

8. Automatic device for the infusion of beverages in accordance with Claim (7) in that when the valve (21) is open, the volume of water under the piston (4) is maintained by a non-return valve (27).

9. Automatic device for the infusion of beverages in accordance with Claim (1) in that the drawer (7) is equipped with a jack (12) and displaced by the water, sucked out on one side of the piston of the jack (12) and driven over to the other side.

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