Infusion device having pressure variation

The present invention relates to a device for infusing a substance to be infused having an infusion chamber for receiving the substance to be infused and for passing a pressurized water flow through the substance to be infused, the infusion chamber having an inlet portion (4) for feeding water into the infusion chamber and an outlet portion (2) for the infused beverage, the injection channel in fluid communication via an injection end with the inlet portion (4) and adapted for connection via an intake end (39) to a pressurized water circuit, characterized in that it comprises adjustable means for varying the water pressure in the injection channel, adapted for generating a water pressure difference between the intake end (39) and the injection end (40) and controlled by control means outside the infusion chamber.

PRIORITY

This application is a U.S. National Phase application of International Application No. PCT/EP2011/058384 filed May 23, 2011, claiming priority to Application No. 10 54014 filed with the French Industrial Property Office on May 25, 2010, the contents of each of which incorporated herein by reference.

The present invention relates to a device for making a beverage by infusing a substance. Ground coffee, loose or in watertight or non-watertight packaging are included in such substances. Tea leaves or other products such as chocolate, soup or plants in leaf or extract form are also part of these substances to which the term infusion in its widest sense extends for the extraction of drinkable components by passing water through the substance. The invention applies particularly to drinks prepared by infusion, and in particular to espresso type drinks.

In this latter field, an espresso coffee is made by infusing a predefined quantity of roasted and ground coffee by passing hot water at high pressure through a previously closed infusion chamber.

The popularisation of espresso coffee has led to the emergence of domestic espresso coffee machines using premeasured portions of coffee in the form of pods or capsules containing the exact amount of previously roasted and ground coffee.

In this field, the infusion is typically accomplished by placing the premeasured dose in a volume, herein called the infusion chamber, through which is passed pressurised hot water. A drink is recovered downstream of the infusion chamber after the extraction of the infusible substance. The extraction phase requires that the chamber is closed, whereas the introduction of the substance and its removal take place with the chamber open.

Different systems have been developed over the last few decades to facilitate the positioning of the portion while limiting its handling. One of the most common systems is the use of an infusion chamber in two parts, one being fixed and the other mobile. The open and closed configurations of the infusion chamber can be generated by the relative mobility of the two parts of the infusion chamber. The publication WO-A1-9507041 is an illustration of this principle with packaging of the substance to be infused in pod form, the inner volume of which is enclosed in a filter paper envelope and a cardboard ring.

One of the two half chambers comprises the intake of pressurised hot water whereas the other has a spout through which the infused coffee is distributed from the pod contained in the infusion chamber. The infusion pressure is generated by a pump equipping the machine and which is usually a vibrating pump the operating principle of which is based on the movement of a magnetic core through a cylinder under the effect of a magnetic coil fed by the mains AC voltage through a diode. The cylinder is tightly connected to the water circuit both upstream and downstream of the pump so as not to leak. A diode cuts out every negative half alternation of the mains and causes the coil to be fed with power during half the time of each alternation. The power of the coil generates a magnetic field in the ferromagnetic parts around it proportional to the number of coil windings and the current flowing through it. The magnetic circuit formed of ferromagnetic parts around the core is intentionally open close to the central core. Under the effect of the coil's magnetic field, induction tend to close the magnetic circuit by the movement of the mobile core. A spring is applied to one side of the core to cause it to return to its initial position in the absence of a magnetic field. Due to the effect of the mains alternating voltage, the central core is moved during half the time of an alternation under the effect of the magnetic field generated by the coil, and returned to its position under the effect of the spring during the second half of the alternation time.

By the action of two non-return valves positioned correctly at the outlet of the tube in which moves the central magnetic core, the said core draws in water upstream of the pump intake and pushes it towards the downstream outlet. There is a relationship between the pressure in the hydraulic circuit downstream of the pump and its flowrate, a relationship that results in a characteristic operating curve and which remains similar for all the vibrating pumps on the market.

Document EP-A1-1 295 554 discloses a coffee machine with a plug fitted against a spring the pre-tensioning of which defines a water pressure to be achieved in order to open the plug and cause the water to circulate in the direction of the ground coffee. This document confirms that the hydraulic behaviour of the water injection circuit is generally defined in the factory.

The invention overcomes at least in part the disadvantages of previously known techniques for this purpose and proposes a device for infusing a substance to be infused with:an infusion chamber for receiving the substance to be infused and passing pressurised water through the substance to be infused, the infusion chamber having a water intake part in the infusion chamber and an infused drink outlet part,an injection channel in fluid communication, by an injection end, with the intake part connectable by an intake end to a pressurised water circuit, characterised in that it comprises means for adjusting the water pressure in the injection channel arranged to generate a pressure difference between the intake end and the injection end.

According to one aspect, control means are used to control the adjustment means from outside the infusion chamber.

Preferably, this control of the pressure from outside the infusion chamber means that there is no need to intervene at the intake part and the outlet part, particular by their side situated inside the infusion chamber. The ability to change the pressure during the infusion process is a particularly interesting feature. Advantageously, the control means comprise means accessible to the user operating the beverage making machine. This accessibility is carried out advantageously from outside the device. The latter is preferably incorporated in a machine that includes other components. In this case, the control can be carried out using means present on the outer surface of the machine, in particular the surface of a hood. This does not mean that the control means are protected by a removable cover. They remain accessible throughout normal use of the device incorporated in the machine.

Thanks to the invention, and preferably without making heavy alterations to the water circuit and by using a conventional pump such as a vibrating pump, the resulting operating pressure and flow inside the infusion chamber can be varied within a wide range of values. This is a significant improvement because, at present, the application of this type of pump or other means for pressurising the water in domestic coffee machines limits their possibilities and it is now accepted that a machine is no longer devoted to one type of beverage or to types of beverages involving similar infusion pressures.

At present, there is significant prejudice against machines devoted exclusively to one type of beverage.

The advantage is to provide the user with new varieties of pods containing substances to be infused very different from espresso coffee, such as chocolate, soup, long coffees, tea and herbal infusions that can be infused in better conditions using the same machine. This advantage relies on the addition of means enabling the pressure/flow values to be adjusted to the ideal values giving the best taste quality for each type of beverage. The machine proposes simple adjustment means, preferably accessible to the user, such as the rotation of a control knob or pressing on a control button.

The advantage is to have a single item of household equipment that can be used to make all types of beverages. This saves considerable kitchen space, reduces energy consumption and generates less waste.

The addition of such an advantageous device also has a major impact on the industrial organisation, the production costs, and on the brand image and customers' perception of quality.

This variable pressure device can also be proposed as an option on machines equipped in series with a fixed device, thereby offering the user the opportunity to improve his/her machine by replacing a few parts and increasing the service life of the machine.

In an advantageous arrangement, the pressure is adjusted through changes to the pressure drops, in particular using components that constitute an obstacle with a variable configuration in the flow of water.

Other aims and advantages will become apparent from the following detailed description. Firstly, the following optional characteristics can be implemented alternatively or cumulatively in the context of this invention:a hood that covers at least partially the infusion chamber, the control means being accessible on the outside of the hood;the control means are configured so as to operate the adjusting means when the infusion chamber is closed;the control means are configured to allow operation of the adjusting means in order to vary the water pressure during the passage of water through the substance to be infused;the control means comprise a manually movable part, the water pressure being a function of the position of the manually movable part;the control means comprise an electric circuit and at least one button for operating the electric circuit;the control means comprise means for storing data relating to at least one pressure curve to be applied during an infusion cycle.the control means comprise a valve fitted opposing the elastic return means and configured to close off the injection channel when the water pressure exerted on the valve is less than the elastic means return force and the means for adjusting the return force;the elastic means comprise a compressible device and the adjustment means comprise means for varying the compression of the compressible device;the means for varying the compression comprise a component pressing on the compressible device, the position of the said component being adjustable to suit the direction of compression of the compressible device,the means for varying the compression force comprise a screw forming a helicoidal slide for movement of the compressing component,the compressing component is a slider that is translationarily movable by tightening or loosening the screw,the screw is fitted so as to be rotationally mobile only and the helicoidal slide is formed between the screw and the slider,the device comprises a surface for blocking translation of the screw, the said surface being movable between an active blocking position of the screw and an inactive position for extraction of the screw,the blocking surface is configured to press against a bearing surface of the screw by exerting a force on the screw opposing the decompression of the compressible part,the device comprises means for applying rotation to the screw,the said means comprise a manually-operated or motor-driven rotational control.the compressible member is a coil spring.

The invention also relates to a machine for making drinks by infusion comprising a device according to the invention and a pressurised water circuit equipped with a pump that may be a vibrating pump.

The invention also relates to a method for infusing a substance wherein the following steps are performed: reception of a substance to be infused in an infusion chamber with water inlet portion and an infused beverage outlet portion; passage of a flow of pressurised water through the substance to be infused via a fluid injection channel in fluid communication with an injection end, with the inlet portion and connected, by an injection end to the pressurised water circuit, characterised in that it comprises a step for varying the water pressure in the injection channel in order to generate a different pressure between the inlet end and the injection end, the said change being operated from outside the infusion chamber.

The variation stage takes place preferably during the passage of the water flow through the substance to be infused.

In the example shown inFIG. 1, and as a preferred arrangement, the invention relates to machines for packaging substances to be infused partly automated to produce beverages from the infusion of the substance in the packaging.

The machine shown inFIG. 1comprises a chassis1in the form of peripheral belt capable of supporting the various internal components. One of these is an inlet portion4, another is an output portion2. Portions2and4may be moved closer together or further apart, for instance by the movement of the inlet portion4which, in the example shown, acts with a cylinder piston which forms the drive means5connected to the input portion4. The cylinder also comprises a body16and means for bringing the infusion chamber back to the default open position. This type of mobility is not limiting and other means of movement fall within the scope of this invention. Similarly, it is also possible to combine the translational and rotational mobilities and a movement of the outlet portion2.

When brought together and docked, the portions2and4define an inner volume that constitutes an infusion chamber. Packaging, for example made from sheets of filter paper joined around their periphery, may contain different substances to be infused as indicated in the introduction to the present description. There follow various procedures in terms of the water flow conditions through the substance to be infused.

Below is an example of water circulating through the invention machine. In general, the machine is configured in order to co-act with a pressurised water circuit. The circuit in question is advantageously equipped with a water storage tank, a boiler capable of heating the water, in particular to make hot beverages, and a pump such as a vibrating pump for pressurising the water in the water circuit up to a predetermined pressure. The circuit is connected to the invention machine by a connection opening8, an example of which is shown in particular inFIGS. 1 and 2, in order to bring the water in the circuit at the intake end39to an injection channel, situated at least in part in the case shown, inside the cylinder constituting the drive means5. More specifically, the piston of the drive means5is guided round a central guide part38within which is formed a downstream portion6of the injection channel, the term “downstream” depending on the direction of the water flow. An upstream portion9of the injection channel is formed, the portions6and9being separated by means which will be detailed further on.

The downstream portion6of the injection channel connects at the inlet portion4to an injection end40shown here in the form of a bowl with perforations capable of ensuring the supply of water to the inner volume of the infusion chamber when the latter is in the closed position. It will be understood that the water passes through the inner volume of the infusion chamber containing the substance to be infused and then flows through one or several passages formed in the outlet portion2towards a spout3at the level of which a container may be positioned. The present invention enables the flow parameters in the machine to be adjusted and especially at the injection channel. In the example shown, the variation consists in a variation of the pressure by a modifiable pressure drop between the upstream portion9and the downstream portion6of the said injection channel. It is to be noted that the configuration shown for the injection channel is not exhaustive.

FIGS. 2 to 5show in greater detail an embodiment of the means for adjusting the pressure of the water in the injection channel.

FIG. 2shows a valve7adapted to apply on an opening in the injection channel between its upstream part9and its downstream part6. More specifically, the injection channel has an intermediate opening in the injection channel at the valve7at which the valve7could have a clearance that allows the water to flow into the injection channel or closes the said duct to prevent the flow of water. The valve7is shown rounded or substantially ogival and closes the injection channel. In order to be applied to the upstream part9, the valve7is fitted opposing the elastic return means in the closed default position. As an illustration, the elastic means may be a coil spring able to be compressed as shown in the various figures. One of the ends of the spring10, the lower end, presses on a part of the valve7opposite its surface plugging the injection channel. The other end of the spring10, the upper end, presses on a support base12shown onFIG. 3. It will be understood that spring compression applies pressure to the valve7so as to place it in the default closed position. This closed position can be countered when the pressure exerted on the valve7by the water from the pressurised circuit is greater than a predetermined value corresponding to the return force applied by the elastic means, in the present case in the form of a spring10. According to the invention, the device is adjustable so that the return force of the elastic means can be varied in order to alter the pressure drops created by the operation of the valve7.

Thus, onFIG. 3, a minimal compression of the spring10is shown producing an initial low return force on the valve7. InFIG. 4, the spring10is further compressed so that the pressure on the valve7increases. An even higher compression is shown inFIG. 5. It will be understood that, whereas in the case ofFIG. 3the pressure downstream of the valve7will be lower and the flow higher, these 2 volumes will evolve inversely as the compression of the spring10is increased. Thus, in the situation shown onFIG. 5, the downstream pressure at valve7is much higher and the flow much less. Thanks to the adjustments of the pressure exerted by the elastic means on the valve7, the flow parameters and especially the pressure can be varied in a wide range, for example between 2 and 20 bars.

This variation takes place in the embodiment shown by way of a system operating a helicoidal slide. More specifically, the compression of the compressible body consisting of the spring10is modified by a translational movement of the support base12on which bears the end of the spring10opposite the valve7. In a preferred arrangement, the support base12is a surface portion of a slider11fitted so as to carry out the translational movement in a direction corresponding to the direction of the spring10in a hole23created in the body of the device as shown in particular onFIG. 6. It will be noted that, onFIGS. 6 and 7the outer shape of the slider11and the shape of the hole23are formed in a similar manner so that these 2 elements coact and the slider11can be advantageously guided in translation by removing its rotational feature. This takes place in particular through the guide surface22, shown here as flats in a relatively oblong section of the slider11.

The slider11has an internal thread24, an example of which is partially shown in the part17of the slider11inFIG. 9co-acting with a second part18added to it. The slider consists advantageously of two asymmetrical parts, one of which is integral with the support base to allow its extraction. The simple shapes of the parts17and18allow economic manufacture by pressurised injection of the plastic material.

The thread24coacts with the threads15of a screw14so as to perform the above-mentioned helicoidal slide. This connection leads to a translational movement of the slider11when the screw14is rotated that can move upwards or downwards the support base12on which applies the compressible device consisting in the example of the spring10.

The screw14has a head25, the configuration of which can be adapted to the required rotational mode of operation. For example, in the case ofFIGS. 9 to 11, the head25comprises a peripheral part constituting a ring gear26facilitating its handling by the user. Thus, the ring gear forms the means providing manual operational control. Other possibilities for rotationally driving the screw14will be described below. In particular, the control means may include an electrical or electronic part for operation by the motor.

The part of the hole23in which is situated the spring10and the valve7is brought into contact with the water flowing in the injection channel (this part of the hole23is an opening that is part of the injection channel in which circulates the water to be brought to the infusion chamber). The seal relative to the rest of the hole23and in particular relative to the part situated outside for adjusting the rotation of the screwed14has to be ensured. To do this, the slider11as a groove19in the example in which can be inserted a seal13adapted to apply a seal on the periphery of the hole23at this preferably circular location. The radial force of the seal causes friction to arise that, in the absence of pressure in the hole23, leads to translational blocking of the slide11. The integration of the seal with the part17forming the slider11forces the movement of the slider11under the action of the thread15on the internal thread24and facilitates its entire extraction if required.

Moreover, the adjustment system can be easily removed, particularly for maintenance or repair work. An example of the ease of dismantling and reassembly is given below with reference to theFIGS. 12 and 19. This dismantling occurs advantageously from the outer shell of the machine without removing any parts of the infusion chamber.

OnFIG. 12has been identified a bearing component21on the body of the screw14able to coact with a portion of a lock28to stop the translation of the screw14in the longitudinally direction. This lock28allows the screw14to make a rotational movement by prohibiting a translational movement. Advantageously, the bearing surface21is formed at a cruise20identified inFIG. 8. The bearing component21is preferably sloping as is the corresponding surface on the lock28. This functional configuration to allow the adjustment of the water pressure as shown onFIG. 12.

When it is required to dismantle the adjustable means, the force exerted by the locking surface33of the lock28on the bearing component21of the screws14has to be countered to allow movement of the lock28. The need to overcome this force is an additional safety feature offered by the invention that avoids a user from not being able to easily move the lock28when the water exerts a high-pressure. Furthermore, the removal of the adjustable means is advantageously made impossible when setting at the highest pressure. Indeed, when adjusting the maximum pressure, the contact surfaces under the slider identified42,42onFIG. 10come into contact with the surface of the limit switch41limiting the upper part of the hole23visible onFIG. 6. In this configuration, the vertical translation downwards of the slider assembly11and the screw14is prevented. The screw14on the slider11then has to be unscrewed in order to decompress the system until there is sufficient distance between the surface21and the locking surface33to permit transversal displacement of the lock28. To this end, the water pressure at part23in which the water flows provides the opportunity for dismantling the adjustable means conditioned at low pressures.

In the case ofFIG. 13, as the pressure is low enough to allow the user to start the movement of the screw14in a compression direction, the lock28can be operated advantageously by the translational movement in a direction transversal to the direction of spring10compression so as to alter its position. The lock28may be moved translationarily through the flat side surfaces30formed on the lock28and co-acting with the rails27formed on a part of the machine body. This example can be seen notably onFIG. 19.

This sameFIG. 19shows transversal stops43, the purpose of which is to limit the travel of the lock28so as not to damage the screw14during assembly by severing this screw at its throat20which has a small cross-section and which is therefore more liable to break.

The lock28that is placed in a position for dismantling brings the assembly to the configuration shown onFIG. 14. At this stage, whereas previously the locking surface33was active in order to prevent the translation of the screw14, the surface33is then inactive and is no longer opposite the bearing component21. Thus, while in this blocking position, the screw14passes through a locking orifice of the lock28and finds itself in the case ofFIG. 14opposite an extraction orifice31, the dimensions of which are such that the screw14is able to cross it. The movement to extract this screw14which follows is shown inFIG. 15.FIG. 16shows a successive extraction stage, the movement of the slider/spring/valve assembly following the extraction movement of the screw14. InFIG. 17, the extraction of the adjustable means has been entirely completed.FIG. 18shows the result in perspective andFIG. 19illustrates the capacity to separate the constituent parts of the adjustable means in particular for their replacement or cleaning.

A first possibility of action by the user is the capacity to act directly and manually on the screw14in order to alter its angular position. This is the case shown inFIGS. 21 and 22in which the device comprises a hood36secured to the chassis1with a lumen37through which the ring gear36of the head25of the screw14is at least partially accessible for handling by the user. An indicator of the angular position of the screws may be provided so that it is possible to read the working pressure corresponding to the angular position of the screw14.

In another possibility, the rotation of the screw14may be motor-driven. This allows operation through a control button, for example positioned on the front of a beverage making machine, or a control that is entirely automatic on the detection of a type of packaging from a list of predetermined types of packaging, each one of which is assigned water pressure settings. For example, the sensor is able to identify a type of packaging based on its colour, its shape, any tag that it might bear or other such system, and generate specific control for the motor drive system.

The motor drive system is shown inFIG. 20in the form of a motor14, such as an electric motor, driving a worm screw35, itself meshing with a ring gear25integral with the screw14.

It is thus possible to simply and effectively vary the pressure/flow operating point of the machine so that it is able to execute low pressure infusion, for example of filter coffee, chocolate or other substances, or ultra-high pressure infusion of tea or, in the intermediate pressure position, the infusion of espresso coffee drinks.

It is to be noted that the change of pressure developed by the invention may take place before an infusion cycle begins so as to reach a target pressure level, or follower pressure curve, at least during part of the infusion cycle. Therefore, the pressure can be adjusted manually or automatically during the infusion process.

The machine may be equipped with data storage means in order to store the pressure curves and/or types of packaging. Advantageously, the user is able to store fixed or variable pressure curves throughout the cycle.

All the parts comprising the device described here can be executed with simple forms enabling them to be manufactured using injected plastic techniques rendering its manufacture extremely economical.