Steam function at the end of a brewing process

ES 2 344 331 T3

DESCRIPTION

Steam function at the end of an infusion process.

The present invention relates to a process for the preparation of hot drinks in a hot drinks machine, in which in a first stage a certain amount of water is pumped from a water tank to a heating installation. In a second stage, this quantity of water is heated in the heating installation. In a third stage the quantity of hot water is pumped from the heating installation to an infusion chamber and at the same time another quantity of water is pumped from the water tank to the heating installation. In a fourth stage, an infusion substance is prepared that is in the infusion chamber to obtain a hot drink. The stages do not necessarily have to take place in separate intervals from each other, but can also take place overlapping each other in time or simultaneously. Therefore, the steps can be understood essentially as defining a component of the process, respectively. During a preparation process, the steps can also be carried out several times. The hot drinks machine can be, for example, a cartridge coffee machine.

From document US 6,405,637 a filter coffee machine is known, which works, in principle, according to the method represented above. A valve at the filter outlet, which is open only when the coffee cup is placed underneath, prevents a subsequent drip of coffee from the used filter.

The object of the present invention is to develop a machine for hot drinks, in such a way that a continuation of the coffee output is prevented at the end of an infusion process also without a valve.

This task is solved by means of the characteristics of claim 1, according to which in a hot drinks machine of the type indicated at the beginning, the power of the pump and / or the power of the heating installation at the end of the process The preparation of a drink is controlled in such a way that the amount of water pumped last to the heating system is almost completely converted into steam. At the end of the preparation process, the last amount of water is therefore selectively converted as completely as possible into steam. The process can preferably be carried out with circulation heaters, which are generally operated with a high surface temperature of more than 100 ° C. Indeed, if the pump does not transport cold water from now on and thus does not cool the hot surface, the last water in the heating installation evaporates. The expansion involved with the formation of steam then presses with at least a part of the resulting steam all the liquids such as water and / or remains of the hot drink from all the fluid-conducting components connected downstream of the heating installation of the machine. hot drinks. In this way, at the end of the preparation, no drink or water can continue to flow out or drip into the beverage outlet.

During the entire preparation process, the heating installation is preferably permanently connected. This saves unnecessary switching processes of the heating installation. The pump can work either in pulses at time intervals, therefore in a pulse and pause relationship. Accordingly, alternating follows an operating interval (pulse), in which the pump runs, and a pause interval (pause). During the pause intervals, the heating system heats the amount of water in it to a specific brewing temperature. Through a corresponding activation, the pump conveys the hot infusion water from the heating installation to the infusion chamber in a timely manner and at the same time conveys fresh cold water from the water tank to the heating installation. Since the generation of steam during the infusion or preparation process is not desirable per se. Indeed, an optimal brewing result is achieved at a brewing temperature of the water clearly below the boiling point. In contrast, temperatures above the optimal infusion temperature or even optimal boiling temperature can have a negative influence on the flavor development of the hot beverage.

The pump can alternately work also continuously when the heating system is switched on. The power of the pump then causes the water to flow through the heating system, which enables the water to be heated to a required temperature. The pump then continuously conveys the water from the heating installation to the brewing chamber. The continuous operation of the pump avoids unnecessary switching processes of the pump and thus increases its service life. The heating power therefore depends on the water outlet temperature, the desired brewing temperature and the volumetric flow of the water. To adapt the heating power to changes in these parameters, its power output can be adjusted accordingly or the heating system can be controlled in a synchronized manner.

At the end of the preparation process, the heating installation is selectively pumped under vacuum, but the pump and the heating installation are switched off essentially at the same time. Therefore, the residual amount of water can remain. Since the heating installation, by virtue of its high operating temperature, now still has sufficient residual heat, the last amount of water in the heating installation is fully heated above the boiling point. In the heating installation, therefore, water vapor is generated and as a consequence of the increase in volume that this implies, pressure is generated, which leads to a short-term steam impact. By virtue of the pressure, all the liquid residues are expelled from the heating installation itself and from the pipes arranged downstream thereof, as well as from the infusion chamber and a cartridge or a capsule arranged therein. If the machine has other

ES 2 344 331 T3 components, such as a foaming chamber or an outlet, these are also completely emptied. Since the entire amount of water in the heating installation evaporates and the pipes downstream from it are emptied under pressure, at the end of the beverage preparation, no more water can leak. In addition, each drink is prepared with freshly heated water. The use of residual water laden, among other things, with germs from the drinking machine for the preparation of the drink can be totally excluded.

In addition to emptying the liquid, the steam line also has a purifying or disinfecting effect. This leads to improved hygiene, especially when the coffee machine is not used for a long time.

Another advantage is the drying effect. The steam expels the liquid remains that have so far remained in the infusion chamber ducts and especially in the cartridge or the capsule that is there. Since the replacement of the cartridge or the capsule is carried out by the user with the machine, this implies a considerable improvement in comfort, since during the extraction of the cartridge or the capsule, residual water is no longer present, and the Removing especially from a dry cartridge is more pleasant than a wet cartridge. In this way, contamination is largely excluded, as would occur, for example, in the case of transporting a dry cartridge from the coffee machine to a waste container.

The process can be used both in cartridge machines as well as in beverage capsule machines. Like cartridges, capsules can contain a solid powdered infusion substance. Alternatively, they can be filled with a liquid infusion concentrate or with a soluble powder. The hot drink is then obtained by diluting the concentrate or the solution of the powder with hot water. During the preparation of the beverage, water is drawn into the capsule and the concentrate or powder is washed off.

Through the instant of disconnection of the heating towards the pump, the intensity of the steam impact can be controlled. An increase can be achieved because the heating is switched off delayed in time with respect to the pump. According to an advantageous configuration of the invention, the pump can be switched off in a time-delayed manner compared to the heating installation. In this way the effect of the pressure impact can be attenuated, so that the driven water is displaced and, consequently, injected less quickly.

The intensity of the steam impact can then be further influenced by the characteristic curve of the heating power or of the pump power during switch-off. If, for example, the heating is not restored immediately and the pump power is not restored immediately and completely, then the impact of steam can be reduced in this way. Conversely, it can be increased when the heating power is continuously restored from the moment the pump is switched off. Through the two controls, therefore, the impact of steam can be controlled in an even more differentiated way than only through the moments of disconnection of the heating and the pump.

According to another advantageous configuration of the invention, at the end of the infusion process, the steam line can also be used to clean one or more sieves, which are located in the liquid supply conduit in front, behind or in the infusion chamber. . Regular cleaning of such sieves slows down their uptime and reduces the number of maintenance intervals at the same time. Especially when several sieves are arranged one behind the other or one on top of the other or in the case of multilayer sieves, in this case, in addition to cleanliness, the emptying of chambers between the sieves is also ensured by end of each preparation process.

The development of the preparation method according to the invention of a beverage machine is explained in detail below by way of example with the aid of a drawing. In the drawing:

Figure 1 shows a block diagram for pulse and pause operation of the pump, and

Figure 2 shows a block diagram for continuous pump operation.

The block diagram according to figure 1 shows five stages of the procedure S_to), S_b), S_c), S_d) and S_and)of a working procedure of a beverage machine, An additional stage of the procedure, which is executed during stage S_and), is designated as S_i). Since stage S_i) it is only done when the machine also has sieves, it is surrounded by a dotted line.

In stage S_to), after the input of a desire for a drink from a control facility, the connection of a pump is triggered. This pumps water from a water tank to a heating installation. The heating installation is connected in the same way. The pump is then switched off again, while the heating system remains switched on.

During step Sb) the water in the heating installation is heated to an infusion temperature. The temperature in the heating installation is monitored in this case by the control system by means of a

ES 2 344 331 T3 NTC resistor, which is arranged in or next to the heating installation. For different beverages, different brewing temperatures can be stored in the control device.

After reaching the infusion temperature, the control system switches on the pump again (stage S_to), so that the heating system remains switched on. In this way the hot infusion water is pumped from the heating installation to an infusion chamber. In the meantime, the heating system is filled again with cold water from the water tank. As soon as the heating system is full, the pump is switched off again.

In the brewing chamber, the hot brewing water now has time to react with a brewing substance there.

The infusion of the infusion substance is carried out with a first partial quantity of hot drink (step S_d), which leaves the brewing chamber through an outlet into a beverage tank.

Stages S_b), S_c), S_d) are repeated until a quantity of water deposited in the control installation for the desired drink has been reached. Repetition is symbolized by the arrow A.

At the end of the preparation process, in stage S_and), the control modifies the activation of the pump and heating; both are permanently disconnected. Due to the residual heat in the heating installation and the remaining pumping of the hot water, its temperature in the heating installation now rises above the infusion temperature to and above the boiling point.

In this way, water vapor appears in the heating system, thereby increasing the system pressure at the same time. This effect is used to completely expel the water found in the pipes or the remains of hot drink that are in the infusion chamber through the outlet. Furthermore, in this case the sieves can be cleaned (step Si), which can be arranged in the conduits or in the area of ​​the brewing chamber.

Therefore, no residual liquid remains in the machine, which could lead, precisely in prolonged inactivity times, to depositions. The hot water steam cleans and disinfects the components passed through by the steam stream and dries them at the same time. The drying further improves the handling of the spent brewing substance, which can be discharged dry more easily and more comfortably, since disturbing drying is suppressed. In addition, through the steam function at the end of the brewing process the post dripping time at the outlet is reduced, if the post dripping is not completely suppressed. The tank filled with the hot beverage can thus be evacuated more quickly from the machine, which essentially improves convenience.

After the new selection of a drink, the sequence of the procedure described above is repeated, symbolized by the arrow B.

On the other hand, the block diagram according to figure 2 represents a procedure with continuous operation of the pump. In opposition to the procedure represented above according to figure 1, now the pump in stage S_to) continuously pumps water to the connected heater. The pump is only switched off again when all the water that is necessary for the preparation of a selected drink has been transported. The pumped water stream is dimensioned in such a way that the water is heated during circulation through the heating fully to the desired temperature. Accordingly, the hot infusion water is conveyed for the infusion of the beverage in step Sd) continuously to an infusion chamber, whereby the preparation of the beverage is continued in the manner described above. Therefore, neither the infusion process Sd) is carried out at intervals or in waves as in the procedure described in FIG. 1, but is characterized by a continuous intake stream of water to the infusion chamber.