HK1078448A - Coffee maker for brewing coffee powder contained in a cartridge - Google Patents

Description

Coffee machine for brewing coffee powder contained in a cartridge

Technical Field

The invention relates to a coffee machine for brewing coffee powder contained in a cartridge, comprising: a brewing chamber adapted to receive a coffee powder packet, at least one device for brewing through the coffee powder packet, and a pump for supplying hot brewing water into the brewing chamber.

Background

Such coffee machines are intended for domestic use, i.e. are intended for domestic use. Compared to a traditional coffee machine with a grinder for grinding whole coffee beans, the main advantages of the above coffee machine are: by using a pre-filled coffee powder cartridge, a high quality grade of coffee beverage can be prepared, especially when the coffee powder is optimally ground and retained in the cartridge in an air-tight manner. Furthermore, such a coffee maker is less subject to contamination by coffee powder.

To brew the coffee powder contained in the cartridge, manually operated or semi-automatic and fully automatic coffee machines are used. Generally, in manually operated coffee machines, the cartridge is inserted into a cartridge holder, which in turn is inserted into the coffee machine. In semi-automatic coffee machines, the cartridge is inserted into a cartridge holder or directly into the brewing chamber of the machine, so as to close the brewing chamber manually with a central lever mechanism. However, in fully automatic coffee machines, the charge is removed from the cartridge and automatically inserted into the brewing chamber; after the brewing operation, the cartridge is removed from the brewing chamber and discarded into a waste container without any intervention by the operator.

Coffee machines of all these kinds mentioned above usually comprise a hollow so-called brewing cone provided with radial outflow openings for injecting brewing water into the pad, the brewing cone being further adapted to punch through the bottom and the lid of the pad, respectively. It is also known that in manually operated coffee machines, the cartridge holder is provided with a plurality of projections on the outlet grid; these protrusions break the lid of the cartridge when brewing water is just injected into the cartridge from the opposite side of the cartridge, and the cartridge is pressed against these protrusions under the influence of the liquid overpressure created by the pressurized brewing water. During the subsequent brewing operation, the brewing water is injected into the cartridge through the brewing tip cone, with the result that the brewing water flows under pressure through the coffee powder contained in the cartridge and out of the cartridge through the openings created by the projections.

Regardless of the fact whether it is a manually operated coffee machine or a semi-automatic or fully automatic machine, the coffee machine is configured and adapted to said cartridge to produce a coffee beverage having foam on its surface; this foam is generally considered to be a characteristic of a good coffee beverage.

Even if great efforts have been made to ensure that the prepared coffee beverage has a long-lasting foam on its surface, there is a need in some countries: conventional coffee in the sense of filtered coffee can also be prepared with these coffee machines. The expression "soft coffee" is also used instead of the expression "filtered coffee".

U.S. patent No. 5,325,765 discloses a beverage filter cartridge comprising an impermeable pierceable floor having a predetermined shape and opening at one end thereof. A self-supporting wettable filter element is disposed in the base plate. It sealingly engages the opening in the bottom plate and has a form different from and smaller than the predetermined shape of the bottom plate, so that the filter element is divided from the bottom plate and divides the bottom plate into two sealed cavities, namely: a first chamber for storing an extract of a beverage to be made; and a second cavity into which a beverage is introduced, the beverage being made by mixing a liquid with the extract and then flowing out of the filter into the second cavity. In addition, it includes an impermeable pierceable lid sealingly engaged with the opening in the base plate to form an impermeable sachet. To extract the coffee powder, the two sides of the pad are punched with upper and lower punch members. The lower punch is eccentrically disposed such that it extends into the second chamber between the base plate and the filter element without damaging the filter element. The pressurized brewing water is fed into the cartridge through the punch. It passes through the coffee grounds and the filter element and into the second chamber. Whereby it flows through the lower punch member into the beverage package.

U.S. Pat. No. 3,537,384 discloses steam and water preparation machines, in particular machines for preparing coffee and tea beverages. It comprises a pump unit and a subsequent boiler. A removable filter head for containing ground coffee is provided. The pump is configured to discharge a constant volume of water per revolution, regardless of the internal resistance of the filter head, resulting in a precisely predetermined volume of water at a predetermined temperature being supplied through the coffee grounds contained in the filter head. By varying the flow rate of the pump and/or the heat output of the boiler, the temperature of the brewing water is said to be changed, so that a conventional coffee beverage or an espresso beverage can be prepared, since different flavourings are dissolved by different temperature levels. In particular, it is to be noted that: for the preparation of espresso coffee beverages it is necessary to use steam at a temperature of 110 ℃ in order to dissolve in particular the bitter flavourings contained in the coffee powder.

U.S. patent No. 4,583,449 discloses a coffee maker for selectively making regular coffee or espresso. It includes a water flow passage extending between the cold water source inlet and the brewing unit. The flow path is divided into: a first branch containing a pressure pump; and a second branch containing a valve adapted to be closed or to be closed in an espresso coffee making mode. It also comprises control means for actuating the valve and/or the pump according to the form of coffee to be made. The flow path is common to water used for making espresso coffee and regular coffee and is divided only in the vicinity of the pump into a first flow path branch containing the pump and a second flow path branch constituting a bypass through the pump.

Disclosure of Invention

The object of the present invention is to provide a coffee machine for brewing coffee powder contained in a cartridge with which not only espresso beverages but also normal coffee beverages can be prepared, the latter one having no foam on its surface and corresponding in taste to normal filtered coffee.

To meet this and other objects, the present invention provides a coffee machine for brewing coffee powder contained in a cartridge, comprising: a brewing chamber adapted to receive a coffee powder packet, at least one device for brewing through the coffee powder packet, and a pump for supplying hot brewing water into the brewing chamber. In addition, means are provided for limiting the amount of brewing water fed into the brewing chamber per unit of time, such that the brewing water flows through the ground coffee pad contained in the brewing chamber, which is substantially non-pressurized.

The formation of foam on the surface of the coffee beverage can be substantially avoided in that means are provided which limit the quantity of brewing water supplied to the brewing chamber per unit of time to such an extent that the brewing water flows through the ground coffee pad accommodated in the brewing chamber which is substantially unpressurized. Preferably, the lid and bottom of the sachet are punched before the brewing operation begins.

Drawings

Embodiments of the coffee maker according to the invention will be further described below with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic view of a coffee maker with an open brewing chamber; and

fig. 2 shows a schematic view of a coffee maker with a closed brewing chamber.

Detailed Description

Figures 1 and 2 show schematically the main elements of a coffee machine according to the invention, namely: a common water tank 1, a pump 2, a boiler 3, a throttle valve 4, a brewing chamber 5, a beverage outlet 6, a control unit 7 and a selector switch 8. All these elements are mounted inside a schematically indicated housing G. A coffee mug 17 is shown below the beverage outlet, the mug 17 being adapted to receive a prepared coffee beverage. The cartridge to be placed in the brewing chamber 5 and containing ground coffee is indicated with the reference numeral 20. In this example, the bottom 22 of the sachet 20 is provided with a hole 25, the hole 25 being covered by a thin metal sheet 26 provided inside the bottom 22 of the sachet 20. Since such a pad is mainly suitable for preparing filtered coffee, it will be referred to below as filter pad 20, whereas a traditional pad without any holes, with an integral bottom, will be referred to as espresso pad.

The brewing chamber 5 comprises an upper closure plate 11 and a bottom packet holder 12. The inner contour of the cartridge holder 12 substantially corresponds to the outer contour of the filter cartridge 20. In the figures, the closure plate 11 and the cartridge holder 12 are shown in cross-section. The cartridge holder 12 is movable in a vertical direction as indicated by the double-headed arrow 18. The means for moving the cartridge holder up and down and possibly the means for feeding and moving the cartridge are not shown, as their structure is well known to the skilled person.

Punched pieces 13 and 15 are provided in both the lower surface of the closing plate 11 and the bottom of the cartridge holder 12, respectively. Thus, the upper punch 13 is used for punching the lid 21 of the cartridge 20, while the lower punch 15 is used for punching the bottom 22 of the cartridge 20. Both punch members 13 and 15 are located centrally in the bottom of the closure plate 11 and the cartridge holder 12, respectively. Furthermore, both punch members 13 and 15 comprise a conical front portion, respectively, which comprises grooves 14 and 16, respectively, through which the brewing water can flow into the cartridge 20 and the prepared coffee beverage can flow out of the cartridge 20, respectively.

The selection switch 8 is used to select the coffee beverage to be prepared. The letter "E" designates espresso coffee, while the letter "F" designates filtered coffee. The selector switch is electrically connected to the control unit 7. The control unit 7 is operatively connected to the pump 2 via a lead 9 and to the throttle valve 4 via a lead 10. The throttle valve is inserted in a line 19 extending from the pump 2 to the closure plate 11. Furthermore, a sensor 28 is provided which is electrically connected to the control unit 7 by means of a conductor 10 a. The sensor 28 is adapted to detect and read a label or indicia 27, which label or indicia 27 is provided on the cartridge 20 and contains information about the type and/or content of the cartridge 20. Such a label or indicia 27, for example, may consist of a bar code printed on the packet 20; however, other kinds of markers are possible, e.g. in electronic form. It will be appreciated that the sensor 28 and the tag or label 27 are matched to one another so as to enable the sensor 28 to read the tag or label 27 and communicate the information contained therein to the control unit 7. In case a single cartridge 20 is used and such a label or marking 27 is provided, the selection switch 8 can be omitted, since the type of cartridge 20 is automatically identified by the sensor 28, and therefore the control unit 7 influences certain operating parameters of the coffee maker, such as the output rate of the pump 2, the adjustment amount of the throttle valve 4, etc.

The brewing operation for preparing foamless coffee, called filtered coffee, is carried out as follows:

the selector switch 8 is manually turned to position "F" and inserts the cartridge 20 into the cartridge holder 12. Then, the holder 12 is moved upward toward the closing plate 11. When this upward movement is completed (see fig. 2), both the lid 21 and the bottom 22 of the sachet, i.e. the sheet 26, are punched. Once the upper end position is reached, the closure plate 11 not only closes the brewing chamber 5, but also squeezes the cartridge lid 21 along an annular contact area against the top end face of the cartridge holder 12, thereby liquid sealing the upper portion of the cartridge 20 with respect to the bottom 22 of the cartridge 20. The pump 2 is activated as soon as the brewing chamber 5 is closed. The quantity of brewing water fed to the brewing chamber 5 per unit of time is limited, when compared to the brewing operation of espresso coffee, to such an extent that: the brewing water flows through the substantially non-pressurized cartridge 20. The flow restriction rate is determined by a pre-selected stored value or based on a number contained in the label or indicia 27 of the cartridge 20. The flow restriction may be achieved by reducing the flow of the pump 2 or by adjusting the throttle valve 4. For reducing the flow of the pump 2, a phase controller or a radio frequency pulse controller may be used in the case of an alternating current driven pump. Alternatively, the operating frequency of the pump 2 may be changed. It should be understood that: in practice, only one measure is taken to reduce the flow of brewing water through the brewing chamber 5 per unit of time, i.e. either means are provided for reducing the flow of the pump 2 or a throttle 4 is provided for reducing the effective flow cross-sectional area. It should also be understood that: other means for reducing the flow rate of brewing water per unit of time through the brewing chamber 5 may be provided.

In any case, the previously mentioned means for reducing the flow rate of brewing water flowing through the brewing chamber 5 per unit of time ensure that: the flow rate, even without counter pressure, is reduced to not more than 12 litres per hour, preferably 8 litres per hour.

It is furthermore important that both the lid 21 of the cartridge 20 and the bottom 22 of the cartridge 20 are punched through, i.e. that holes are provided before the brewing operation is started, to ensure that no liquid pressure is generated, which would cause foaming in the beverage.

As can be further seen in the figures, the filter cartridge 20 is provided with an upper filter element 23 and a lower filter element 24. Such filter elements 23, 24 facilitate a constant flow of the infusion water through the filter cartridge 20 and prevent the coffee powder contained in the cartridge 20 from escaping through the holes punched out. Each filter element 23, 24 is provided with a recess directed towards the inside of the cartridge 20, said recess being located in the punched area of the lid 21 and the bottom 22 of the cartridge 20, respectively, and the punches 13, 15 extend into the cartridge 20 once the cartridge lid 21 and the bottom 22 are punched through. In order to ensure that the bottom 22 of the cartridge 20 is reliably punched through when closing the brewing chamber 5, a thin metal sheet 26 is provided, which thin metal sheet 26 has a low ductility and a low tensile strength compared to the material of the cartridge itself, so that it is easily torn open by the action of the lower punch 15 at the bottom of the cartridge holder 12.

To prepare a conventional espresso, the selector switch 8 is manually turned to position "E". In this mode of operation, the brewing water flows under high pressure through a conventional espresso cartridge. In this case, the word "espresso" will denote a coffee beverage having a foam layer on top of it, irrespective of the amount of brewing water used for preparing the coffee beverage. For preparing filtered coffee, it is preferred to use a different sachet than for preparing espresso. In addition to the different configuration of the bottom of the cartridge, there may be different blends of coffee powder, amounts of coffee powder and/or degrees of grinding. Furthermore, in the case of filtering coffee pods, the cuts in the filter elements 23, 24 are larger and/or their number is increased, so that the filter elements 23, 24 do not constitute a liquid resistance to the brewing water flowing through the grooves there.

As an alternative to the embodiments discussed previously herein, the coffee maker may contain a wider range of features: for example, means may be provided for brewing through the bottom of the cartridge after brewing through the cartridge lid, depending on the kind of coffee beverage to be prepared. In the case of espresso coffee to be prepared, the bottom of the espresso coffee cartridge is only punched through after a certain liquid pressure has built up inside the cartridge, since this measure, as is known, facilitates the generation of foam.

On the other hand, in the case of an espresso coffee cartridge, the bottom thereof is only partially punched by the lower punch in the first stage, i.e. to such an extent that: the end of the punch has just penetrated the bottom of the pad, but the slot 16 of the punch 15 is not in communication with the inside of the espresso pad. In this way, during the first phase of the brewing operation, an overpressure of liquid can be established inside the espresso coffee cartridge.

On the other hand, in the brewing of a coffee beverage by means of a filter cartridge, the lid and the bottom of the filter cartridge are flushed through before the actual brewing operation begins, in order to avoid an overpressure of liquid inside the filter cartridge, which would be advantageous for the generation of foam.

The coffee machine according to the invention is known under the name "espresso machine"; it is suitable for preparing filtered coffee beverages and in particular espresso beverages. The coffee machine may be configured as a manually operated machine, with a cartridge holder that can be manually inserted into the machine, or as a semi-automatic or fully automatic coffee machine.

To achieve the above measures, for example, the lower punch 15 at the bottom of the cartridge holder 12 is vertically adjustable. The adjustment of the height position thereof can be done by means of an electric motor or an electromagnet under the control of the common control unit 7.

Claims (14)

1. Coffee machine for brewing coffee powder contained in a cartridge, comprising: a brewing chamber adapted to receive said coffee grounds packet, at least one device for brewing through said coffee grounds packet, and a pump for supplying hot brewing water into said brewing chamber; the method is characterized in that: it further comprises means for limiting the quantity of infusion water fed to said infusion chamber per unit of time, so that it flows through said ground coffee pad contained in said infusion chamber, which is substantially non-pressurized.

2. A coffee machine according to claim 1, characterized in that: said means for limiting the quantity of brewing water limits the quantity of brewing water fed into said brewing chamber per unit of time to not more than 12 litres per hour.

3. A coffee machine according to claim 1, characterized in that: at least two punch members are provided for punching through the bottom of the cartridge and the lid of the cartridge, whereby means are provided for punching through the bottom of the cartridge and the lid by means of the punch members before the brewing water is supplied to the cartridge by means of the pump.

4. A coffee machine according to claims 1 and 3, characterized in that: the brewing chamber comprises a cartridge holder and a closure plate, each of which is provided with a punch, so that the coffee machine further comprises means for moving the cartridge holder and the closure plate relative to each other from an open state to a closed state of the brewing chamber, so that when closing the brewing chamber, the cartridge contained in the brewing chamber is punched through at its lid and at its bottom by means of the punch.

5. A coffee machine according to claim 4, characterized in that: both the closure plate and the cartridge holder are provided with a centrally located punch.

6. A coffee machine according to claim 4, characterized in that: the closure plate or the cartridge holder is provided with a centrally located punch.

7. A coffee machine according to claim 1, characterized in that: the means for limiting the quantity of brewing water fed into said brewing chamber per unit of time comprise means for limiting the flow of said pump.

8. A coffee machine according to claim 7, characterized in that: the pump is driven with alternating current, whereby the means for limiting the pump flow comprises a phase controller, a radio frequency pulse controller or a variable frequency controller.

9. A coffee machine according to claim 1, characterized in that: the means for limiting the quantity of brewing water fed into the brewing chamber per unit of time comprise an adjustable throttle valve inserted in a conduit extending from the pump to the brewing chamber for varying the effective cross-sectional flow area of the conduit.

10. A coffee machine according to claims 1 and 9, characterized in that: a manually operated selector switch is provided that is connected to a control unit such that the control unit is operatively connected to the pump and/or the throttle valve to limit the amount of brewing water supplied to the brewing chamber per unit of time.

11. A coffee machine according to claim 4, characterized in that: when closing the brewing chamber, the closure plate is adapted to press the cartridge along an annular seat area against an end surface of the cartridge holder.

12. A coffee-making machine according to claims 1 and 10, further comprising: at least one sensor for decoding a label or a tag provided on the cartridge, whereby the sensor is operatively connected to the control unit for limiting the amount of brewing water supplied to the brewing chamber per unit of time depending on the information content of the label or tag.

13. Coffee powder cartridge adapted to be used in a coffee machine according to claim 1, the bottom of the cartridge comprising an aperture covered by a thin metal sheet, the thin metal sheet being fitted inside the bottom.

14. A coffee powder cartridge according to claim 13, which cartridge comprises a cup-shaped lower part, the bottom of which constitutes the bottom of the cartridge, whereby the foil covering the hole provided in the bottom of the cartridge is made of a material having a lower ductility and a lower tensile strength than the material of the cup-shaped lower part, so as to ensure that: the thin metal sheet is reliably torn under the action of the punch when the brewing chamber is closed.