FR2788954A1 - Coffee machine for preparing expresso coffee includes diffuser with inclined exterior wall inclined to control spread of injected water on coffee - Google Patents

Abstract

Machine has filter (1), wire screen (2) behind hot water injection circuit (15) allowing no water to pass onto coffee, jack (4) and piston (5) fixed by face (6) to screen moving down to compress coffee. Diffuser (7) is placed between screen and piston to produce turbulent spray of hot water, and has outer channel (11) with exterior wall (12) inclined to control spread of injected water on coffee.

Description

The present invention is a machine for the preparation

espresso type coffees.

  In this field, the machines are capable of filling a container such as a cup with coffee by passing hot water over a dose of ground coffee. Such machines include a filter allowing reception of the dose of ground coffee and a consecutive shower of a hot water injection circuit allowing

  the passage of hot water on the ground coffee.

  The present invention also relates to a process for preparing an espresso type coffee. The process according to

  the invention will be able to implement the machine presented.

  The process and the machine according to the invention may find their application in the field of manufacturing and

  the use of espresso-type coffee machines.

  The invention applies more particularly to machines for making espresso using non-pre-dosed ground coffee. In this field, numerous devices are currently known which do not, however, allow firing

  take full advantage of the beneficial components of coffee.

  In this context, European patent application EP 0 545 853 is more particularly known. This document presents an espresso coffee machine which essentially comprises a casing, a fresh water tank, a hot water preparer, a pump, a motor for piston, a piston for compacting the ground coffee, an infusion chamber for receiving the ground coffee and a hot plate. The engine that drives the

  piston is a DC motor.

  Current machines and especially those corresponding

  in document EP 0 545 853 have different drawbacks.

  Firstly, the existing tamping systems are produced with an additional tamping member. It follows a complex conception of the machines using an organ of

  tamping and an additional cost.

  Furthermore, the packing carried out according to document EP 0 545 853 does not allow the packing to be maintained during the forced leaching. We therefore obtain a packing of poor quality. Another disadvantage of current machines is that, even if packing is carried out, the distribution of the flow of hot water passing over the dose of ground coffee is poor. Indeed, there is a non-uniform flow of water on the dose of coffee. Water thus tends to find a preferential path during forced leaching, in particular by the edges of the

  filter for receiving the dose of ground coffee.

  Therefore, it is not currently possible to extract all the aromas contained in the dose of ground coffee, which

  harms the quality of the coffees produced.

  Furthermore, the machines do not allow forced leaching to be limited to the extraction of the components.

  aromatic beneficial to the quality of the coffee.

  These aromatic elements are mostly extracted at the start of leaching. The end of leaching leads to the passage of acid and other harmful elements such as caffeine. Thus, if you prolong the forced leaching, there is a strong risk of obtaining poor quality coffee with

  high caffeine and acid content.

  However, no current machine makes it possible to obtain a coffee beverage of sufficient volume while avoiding prolonging the forced leaching beyond the phase o

  the extraction of the beneficial aromatic elements is completed.

  We can therefore only make very short coffees or

  longer, but much lower quality coffees.

  In general, it should be noted that the current quality of the espresso produced is clearly optimizable. Indeed, the various drawbacks highlighted above have significant repercussions on the quality of the product produced. The invention proposes to remedy these drawbacks in order, during all the phases of preparation of the espresso, to avoid the degradation of

  properties of espresso type drinks.

  One of the first aims of the invention is to propose a machine integrating efficient packing means. To do this, the machine has the advantage of integrating means of

  tamping in the hot water injection system on the coffee.

  Compaction is therefore maintained during the forced leaching and possibly during a prior wetting of the

dose of ground coffee.

  Furthermore, the tamping means according to the invention make it possible to dry the dose of ground coffee at the end of

forced leaching.

  Another object of the invention is to provide a better flow of water over the dose of ground coffee. To do this, the machine includes possibilities for specific spraying of the dose by particular design of a diffuser placed in

upstream of the hand shower.

  The invention also makes it possible to master all the stages of the preparation of the drink of the espresso type. These stages notably include tamping, infusion or

soaking, forced leaching.

  The invention firstly has the advantage of allowing the consecutive implementation of these three stages. It also makes it possible to limit forced leaching to a predetermined volume of water or as a function of the drop in water flow. In this way, it is possible to extract the desirable components of the dose of ground coffee (essentially the aromatic elements) while avoiding a massive extraction of the

  unfavorable elements (such as acids or caffeine).

  The water flow parameter is important because the applicant has highlighted that its evolution was linked to the coffee manufacturing phases: - a drop in the flow rate during brewing reveals that optimum inflation of the ground coffee is reached, - a decrease in flow during forced leaching reveals that most of the beneficial components

coffee has been extracted.

  The present invention also has the advantage of allowing adjustment at will of the dilution of the coffee drink produced. The implementation of the method and of the machine according to the invention therefore makes it possible to increase the quality of the coffee while

  throughout its preparation stages.

  Other goals and advantages will emerge during the

  description which follows which is however only given

indicative title.

  The present invention relates to a machine for preparing espresso type coffees, capable of filling a container with coffee by passing hot water over a dose of ground coffee comprising: - a filter for receiving a dose of ground coffee - a shower downstream of a hot water injection circuit, allowing the passage of hot water over the dose, characterized in that it comprises means for translating the shower to compact the dose of ground coffee. It also relates to a process for preparing a coffee of the espresso type, capable of filling a container with coffee by passing hot water over a dose of ground coffee, which can be implemented by the machine, characterized in that the the following successive steps are implemented: - the dose of ground coffee is cup the sprinkled dose of hot coffee is sprayed with hot water at network pressure until a drop in the water flow is measured or after a predetermined time in order to make an infusion of ground coffee before the

forced leaching.

  The method and the machine presented here can be implemented according to different embodiments including the following: - The means for translating are formed by a jack whose piston has a fixing face of

the hand shower.

  - A diffuser is inserted between the shower and the piston to create turbulence and distribute the water

  hot injected into the dose of ground coffee.

  - A peripheral channel whose outer wall is inclined to control the distribution of water

  injected on the dose of ground coffee is present.

  - The inclination of the outer wall of the peripheral channel is equivalent to that of the periphery of the

bottom of the filter.

  - The machine includes means for measuring the water flow injected to control the stopping of the circulation of water in the injection circuit when a predetermined value of water volume or threshold flow is

  reached, to limit forced leaching.

  - It has a circuit for direct addition of hot water to the coffee container, making it possible to obtain

the desired dilution.

  - The circulation of hot water in the circuit (s) is controlled by solenoid valves controlled by a

control center.

  - The rise and fall of the piston is controlled by two solenoid valves, one for the rise, the other for the descent, said solenoid valves being controlled

by a control center.

  - The control unit automatically closes the solenoid valve for controlling the circulation of hot water in the injection circuit when the information on the flow of injected water transmitted by the measurement means is equal to the predetermined value of threshold flow or that the volume of water injected is equal to the value

  predetermined maximum water volume.

  - After tamping and spraying, hot water overpressed on the dose of ground coffee is injected to achieve forced leaching, while measuring the volume of water injected, the hot water injection is stopped when a predetermined value volume of hot water is

  reached or when a drop in flow is measured.

  - Add, after leaching, a quantity of hot water directly in the container, according to the dilution

desired.

  - After the forced leaching, a compaction of the

ground coffee to dry the dose.

  The attached drawings are given by way of indicative and non-limiting example. They represent an embodiment according to the invention. They will help to understand

easily the invention.

  Figure 1 illustrates an exploded view of some elements

of the invention.

  Figure 2 is a diagram illustrating the circulation of water within the machine according to the invention and the control

of this circulation.

  Figure 3 illustrates the machine according to the invention in view

  partial in a particular embodiment.

  In general, the preparation of espresso type coffees is done by machines allowing the passage

  under hot water pressure on a dose of ground coffee.

  Generally, the dose of ground coffee is received in a filter 1 as shown in Figure 1. This figure shows a filter 1 for a dose corresponding to a cup of coffee and also a deeper filter 1 corresponding to

  one serving for two cups of espresso coffee.

  As shown in FIG. 2, the machine according to the invention

  will include a boiler 21 capable of heating the water used.

  In addition, a pumping system will be used to boost the water in order to achieve leaching. This pump

  is represented by the reference 20 in FIG. 2.

  Downstream of the pump 20 and the boiler 21, hot water is circulated until it is injected into the dose

  ground coffee received in filter 1.

  The hot water injection circuit 15 is also shown in FIG. 2. This injection circuit 15 ends

  commonly by a hand shower 2 shown in Figure 3.

  Shower 2 is the end element of the circuit

  15 and allows the spraying of the dose of ground coffee.

  The part of the machine for heating and injecting hot water into the ground coffee is generally called a group. Group 3 is partially shown in Figure 1. The shower 2 is generally partially fixed

  group 3 thus formed.

  According to the invention, the machine comprises means for translating the spray head 2. These means for translating allow the dose of ground coffee to be packed. In addition, they make it possible to prolong this compaction, including during the possible infusion phase and that of

forced leaching.

  In a particular embodiment, the translational means are formed by a jack 4 such that

shown in figure 3.

  This figure shows a hydraulic cylinder 4 but any other type of cylinder and in particular a pneumatic cylinder can be used. According to Figure 3, the cylinder 4 comprises a piston 5 itself comprising a face of

attachment 6 of the hand shower 2.

  As shown in Figure 3, the attachment of the shower 2 on the attachment face 6 can be achieved at

by means of a central screw 10.

  As shown in Figure 3, the injection circuit 15 ends, on the hand shower 2, through a channel

  injection 9 formed through the piston 5.

  FIG. 3 also illustrates certain conventional constituent elements of a coffee machine and in particular a peripheral seal 23 for sealing the door

filter 22 illustrated in FIG. 1.

  In a particular embodiment, the machine according to the invention comprises a diffuser 7 also presented in FIG. 3. The diffuser 7 is interposed between the spray 2 and the piston 5 in order to receive the flow of injected water. In this way, the water injected from the injection circuit 15

  is set in turbulence and distributed over the dose of ground coffee.

  Preferably, the diffuser 7 has a peripheral channel 11 whose outer wall 12 has a predetermined inclination. The choice of this inclination makes it possible to control the distribution of the water injected over the dose of ground coffee. The inclined outer wall 12 is also shown in FIG. 3. To promote good distribution of hot water over the dose of ground coffee and, in particular, avoid preferential passage of water at the bottom 13 of the filter 1, will form an exterior wall inclination 12 of one level

  equivalent to the inclination of the periphery 13 of the bottom of the filter 1.

  As shown in Figure 3, obviously 8 is advantageous

  to receive the diffuser 7 on the fixing face 6.

  As indicated previously, the invention has the advantage of allowing a limitation of the forced leaching to a predetermined volume of water in order to limit the extraction to the beneficial elements present in the ground coffee and mainly the

aromatic elements.

  To do this, the machine according to the invention may include means 14 for measuring the flow of water injected such

as shown in figure 2.

  As illustrated, the means 14 make it possible to obtain a flow measurement represented by the letter "D". The measurement carried out is then injected into a control member referenced 17 in FIG. 2. A measurement of the injection time can also be carried out at the control member by a chronometric counter. It is thus possible to control the stopping of the circulation of water in the injection circuit 15 according to one of the following three criteria: - a predetermined time for circulation of water has elapsed; - a predetermined volume of water has been injected; the volume of water injected being easily deduced from the connection of the circulation time and the flow rate;

  - a drop in water flow is measured.

  In the illustrated embodiment, the machine also comprises a circuit for direct addition 16 of hot water to the coffee container. In this way, the dilution of the drink can be adjusted as desired according to the wishes of the user. In doing so, the forced leaching is not continued beyond the extraction of the beneficial elements corresponding to the predetermined volume of water "V". To compare the value of the parameter of flow rate D, time and volume of water with the predetermined values and to stop or start the injection of hot water into the circuits (15 and 16), we Preferably use a control unit 17. FIG. 2 illustrates this control unit 17 comprising as input parameter the measured water flow "D" and having connections with solenoid valves referenced 18 and 19. The solenoid valve 18 controls l or closing the injection circuit 15. The solenoid valve 19 controls the opening or closing of the addition circuit

direct 16.

  Based on the comparison made between the flow value "D" and the predetermined value, the control unit

  17 will act on the solenoid valves 18, 19.

  In a particular embodiment of the means for translating the spray 2, the piston 5 is raised and lowered by a hydraulic cylinder 4

  having an ascent circuit and a descent circuit.

  As illustrated in FIG. 2, the rise of the piston 5 can be controlled by a solenoid valve 24 and the descent can

  be controlled by a solenoid valve 25.

  The command to open or close the solenoid valves

  24, 25 can be implemented by a control unit 17.

  In the case of FIG. 2, a single central unit 17 is used for the control of raising and lowering of the piston 5 and of opening and closing of the injection circuits 15 and

direct addition 16.

  The machine according to the invention can be implemented according to the following operating steps described in

  a particular embodiment.

  Reference is made to the sequence of this operation in Figure 2 illustrating an embodiment of the invention. Once the user has positioned the dose of ground coffee in filter 1 and the latter is maintained at the level of the lower part of group 3 by means of the filter holder 22, the user can initiate the start-up of

the machine.

  At this start-up, the central control unit 17 performs an opening of the solenoid valve 25 for the descent of the piston 5. Preferably, an infusion step will then be carried out prior to the forced leaching. To do this, the control unit 17 controls the opening of the solenoid valve 17 in order to allow the circulation of water in the injection circuit 15. This circulation is only carried out, for the infusion phase, at network pressure. The pump

is then inactive.

  An adjustable time delay can be used to set a

predetermined infusion time.

  The infusion can also be stopped before the end of the timer if a drop in water flow D below

  a predetermined threshold is measured.

  Once the infusion has been carried out, the pump 20 is activated, for example by the control unit 17 also, so as to circulate the hot water under pressure in the

injection circuit 15.

  Forced leaching is then initiated.

  During the phase of forced leaching, measurement means 14, positioned as in FIG. 2 between the pump 20 and the boiler 21 and which can be constituted by a flow meter,

  performs a measurement of the water flow "D".

  This value "D" is received at the level of the control unit 17 in order to deduce therefrom the volume of water injected (knowing the injection time) in order to perform a

  comparison with a predetermined water volume value.

  This predetermined value is fixed by construction or by the user according to the volume of water necessary for leaching to release the beneficial elements from the ground coffee without extracting the unfavorable elements. When the value of the volume injected reaches the predetermined value, the control unit 17 stops the circulation of water in the injection circuit 15 by closing

of the solenoid valve 18.

  Furthermore, the injection can be stopped when a drop below a predetermined flow threshold

of water D is measured.

  The combination of these two stop conditions can be achieved and the closing of the solenoid valve 18 will occur as soon as

  that either of the two conditions will be checked.

  The decrease in the water flow rate D in the leaching phase corresponds in fact substantially to the end of the extraction of the beneficial elements from the ground coffee but the criterion of volume of water injected may be useful to compensate for an absence of

significant drop in water flow.

  Automatically or by manual control of the user, an opening of the solenoid valve 19 can be carried out in order to allow the circulation of water in the direct addition circuit 16. In this way, a dilution

espresso is made.

  After this stage or simultaneously, it is possible to carry out an additional packing of the dose of ground coffee in order to dry it. To do this, the control unit 17 can command an additional descent of the

  piston 5 by playing on the opening of the solenoid valve 25.

  Once this step has been completed, the solenoid valve 25 can be closed and the rise solenoid valve 24 activated so as to raise the

piston 5 in rest position.

  Likewise, the solenoid valve 19 is closed at the end of direct addition of water to the container, either manually by the user once the desired dilution is reached,

either automatically.

  In a particular embodiment of the machine according to the invention, the pump 20 is used not only for carrying out the overpressure of hot water in the injection circuits 15 and direct addition 16 but also for the supply of the solenoid valves 24 and 25 controlling the

raising and lowering of the piston.

  The process for preparing an espresso type coffee presented here has the advantage of combining the steps of tamping down the dose of ground coffee and sprinkling this dose with water.

hot at network pressure.

  In this way, an infusion of the ground coffee is made while maintaining a compaction. For the infusion step, the pump 20 is not necessary, the expansion of the hot water sufficient to

  bring it up to the dose of ground coffee.

  In a particular embodiment of the method, after compaction and sprinkling for infusion, an injection of hot water is carried out to effect forced leaching while measuring the flow rate and calculating the volume.

water injected.

  In this way, it is possible to stop the injection of hot water when the measured value reaches a predetermined value. By the process presented here, it is also possible, after forced leaching, to directly add a quantity of hot water to the container of the espresso in order to obtain the

desired dilution.

  Finally, an additional packing of the

  dose to dry the ground coffee.

  Each of the stages and each of the means described above makes it possible to optimize the quality of the espresso obtained. Their global implementation gives the drink a

  level of quality not currently existing.

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Claims (14)

  1. Machine for preparing espresso type coffees, capable of filling a container with coffee by passing hot water over a dose of ground coffee, comprising: - a filter (1) for receiving a dose of ground coffee; - a hand shower (2) downstream of a hot water injection circuit (15), allowing the passage of hot water over the dose, characterized in that it comprises means for translating the   hand shower (2) to compact the dose of ground coffee.   2. Machine according to claim 1 characterized in that the translational means are formed by a cylinder (4) whose piston (5) has a fixing face (6) of the hand shower (2).   3. Machine according to claim 2, characterized in that a diffuser (7) is interposed between the spray (2) and the piston (5) to put in turbulence and distribute the water   hot injected into the dose of ground coffee.   4. Machine according to claim 3, characterized in that the diffuser (7) has a peripheral channel (11) whose outer wall (12) is inclined to control the   distribution of the water injected over the dose of ground coffee.   5. Machine according to claim 4, characterized in that the inclination of the outer wall (12) of the peripheral channel (11) is equivalent to that of the periphery (13) of the bottom of the filter (1).   6. Machine according to any one of claims 1 to   , characterized in that it comprises means (14) for measuring the flow of water injected to control the stopping of the circulation of water in the injection circuit (15) when a predetermined value of volume of water or flow threshold is reached, in order to limit forced leaching.   7. Machine according to any one of claims 1 to   6, characterized in that it has a circuit for direct addition (16) of hot water to the container of the coffee, making it possible to obtain the desired dilution.   8. Machine according to claim 6 or 7 characterized in that the circulation of hot water in the circuit (s) (15, 16) is controlled by solenoid valves (18, 19)   controlled by a control center (17).   9. Machine according to claim 2 in combination with   any one of claims 3 to 8, characterized by   fact that the raising and lowering of the piston (5) is controlled by two solenoid valves (24, 25), one (24) for raising, the other (25) for lowering, said solenoid valves (24, 25)   being controlled by a control unit (17).   10. Machine according to claims 6 and 8 characterized   by the fact that the control unit (17) automatically closes the solenoid valve (18) for controlling the circulation of hot water in the injection circuit (15) when the information on the flow rate of injected water transmitted by the means (14) is equal to the predetermined threshold flow value or that the volume of water injected is equal to the predetermined value of maximum water volume.   11. Method for preparing espresso type coffee, capable of filling a container with coffee by passing hot water over a dose of ground coffee, which can be implemented by   machine according to any one of claims 1 to 10,   characterized by the fact that the following successive steps are implemented: - the dose of ground coffee is cup, - the dose of ground coffee is sprayed with hot water at the network pressure until a drop in water flow or after a predetermined time, in order to make an infusion of ground coffee before forced leaching.   12. Method according to claim 11, characterized in that after compaction and sprinkling: - hot water overpressed on the dose of ground coffee is injected to carry out the forced leaching, while measuring the volume of water injected - the hot water injection is stopped when a predetermined value of hot water volume is reached or   when a drop in flow is measured.   13. Method according to claim 11 or 12 characterized in that one adds, after the forced leaching, a quantity of hot water directly in the container, according to the desired dilution.   14. Method according to any one of claims 11 to 13, characterized by the fact   after forced leaching, the ground coffee is packed to dry the dose.