EP2519128A1

EP2519128A1 - Hot-beverage machine with a valve arrangement

Info

Publication number: EP2519128A1
Application number: EP10790402A
Authority: EP
Inventors: Josef Daburger; Wolfgang Georg; Ulrike Gerl
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2009-12-29
Filing date: 2010-12-07
Publication date: 2012-11-07
Also published as: WO2011080029A1; US20120240783A1; DE102009055384A1; CN102665505A

Abstract

The invention relates to a hot-beverage machine (1) with a water-storage tank (3), a heating device (15) and a brewing chamber (23), these being connected to one another by a conduit system (9a, 9b), and with a valve arrangement (19; 19a; 19b) in the conduit system (9a, 9b). It is developed according to the invention in that the valve arrangement (19; 19a; 19b) comprises a gas-permeable membrane (39). The invention also relates to the use of such a valve arrangement (19; 19a; 19b).

Description

Hot beverage machine with a valve arrangement

The invention relates to a hot beverage machine for household use with a water storage tank, a heater and a brewing chamber, which are interconnected by a conduit system, and with a valve arrangement in at least one line section of the conduit system. The invention also relates to the use of a valve assembly in a piping system of a hot beverage machine between a water storage tank and a brewing chamber as a pressure equalization valve. The DE 10 2007 058 375 A1 describes a hot beverage machine of the type mentioned. The valve arrangement is designed as an automatically switching overpressure or vacuum valve of a coffee pod or multi-beverage machine, which is additionally actuated independently of pressure. In order to open or close such an overpressure or vacuum valve, a certain force has to be exerted that is above a certain threshold value. At very low pressure differences, however, do not create sufficient forces to lead to a corresponding change of the valve (closing or opening).

It is an object of the invention to enable an improved pressure equalization.

This object is achieved by a hot beverage machine of the type mentioned, in which the valve assembly comprises a gas-permeable membrane. A gas-permeable membrane is understood as meaning such a membrane which, owing to its pore size, allows the passage of those gaseous constituents of the air which make up its greatest volume fraction. In particular, nitrogen and / or oxygen are allowed to pass through. It is assumed that the passage of said gaseous air components is possible at least in the pressure range that typically occurs in a hot beverage machine. This pressure range is currently between 300 mbar (at low pressure) and 15 bar (at very high overpressure) for currently used hot beverage machines such as coffee machines. Moreover, it is advantageous if the membrane under the specified pressure conditions is additionally formed water vapor permeable, so that water vapor can escape.

As a valve assembly is generally understood a one- or multi-part arrangement of functional parts including housing parts and / or fasteners, the interaction of their function of a valve, namely the - automatic and / or actuators - controlled Durchläse of fluids meet. A valve assembly may therefore be composed of several components or be a very simple, consisting of only one component valve, such as a hose valve that is squeezed at overpressure that it closes.

Instead of a mechanically operated by means of an opening and closing mechanism valve, the invention thus uses a gas-permeable membrane as a pressure compensation element. This allows pressure equalization between the piping system and its environment to begin almost immediately when a pressure differential arises. Even a slight difference in the single-digit mbar range is sufficient to effect a gas flow through the membrane. This has the advantage that overpressure or underpressure in the piping system can be reduced faster and more completely than when using a mechanically opening or closing valve.

In addition, the inventive valve assembly is much less susceptible to contamination, because it completely manages without mechanical moving parts that could be affected by contamination. This danger for mechanical valves is especially in applications with very calcareous tap water. Deposits on the membrane, which could also affect their effect, can be counteracted by an easy-to-carry cleaning on the inside of the membrane facing the conduit system.

The use of a gas-permeable membrane as an element of the valve arrangement also has the advantage that the valve arrangement can provide pressure compensation in both flow directions without external influence. It acts as a bidirectional valve, but without the double risk of contamination as with a mechanical bidirectional valve. According to a first variant of the invention, the valve arrangement is arranged in a line section between the water storage tank and the heating device. In this case, it serves primarily to compensate for negative pressures. Negative pressures may be created by cooling the piping system while condensing water vapor at the end of a brewing process. Upstream of the heater so the resulting negative pressure is reduced, so that no water is sucked from the water storage tank in the direction of the heater.

Alternatively or additionally, the valve arrangement is arranged according to a second variant of the invention in a line section between the heater and brewing chamber. Here it serves primarily to compensate for overpressures that are built up towards the end of a brewing process when a steam pulse is generated to clean the brewing chamber and the brewing product stored there or a brewing capsule used there. The remaining after the steam surge pressure can be reduced by means of the pressure relief valve. As a result, can be reduced as the result of negative pressure during cooling of the system.

The membrane is substantially impermeable to water in a pressure region which usually occurs in the line section-in particular, in the above-indicated pressure zone. This prevents inadvertent leakage of moisture, especially (hot) beverage preparation water, from the piping system. This could cause damage to the hot beverage machine or to scalding users of the beverage machine. The pore size of the membrane is thus chosen so that the larger compared to most gas molecules water molecules can not get through, at least in the liquid state of aggregation. The removal of water vapor, however, - as already mentioned above - may be desired.

Advantageously, it is provided that the membrane comprises a material made of polytetrafluoroethylene (PTFE). This membrane material which is for example marketed by Gore under the trade name GORE-TEX ^® is well proven, and easily and in virtually any packaging available. It is flexible and can therefore be designed, for example, as a hose. It is therefore a possible advantageous embodiment of the invention, that the membrane as

Hose element is integrated in the pipe system. This saves space in the

Integrated line system and also offers a large surface, via which a pressure equalization can take place. In order to enable the fastest and most effective pressure equalization, it can also be provided that the membrane is coated in a water-repellent manner. The water present in the pipe system thus rolls off the membrane, so that even solids contained in the water, in particular lime, can not readily deposit on the membrane or clog their pores. Thus, the maintenance of the valve assembly can be effectively reduced.

This purpose is also an advantageous development, according to which the membrane is removably disposed in the valve assembly. Instead of replacing the entire valve assembly, only the consumable material, d. H. the contaminated membrane removed and possibly cleaned or replaced. A removability of the membrane may, for example, be made possible by the membrane being clamped in the valve arrangement. This can be done for example by means of two clamping parts of a valve housing, which are positively connected with each other by a screw or a bayonet lock or by means of a clip. By opening the closure, the membrane is then released. Alternatively or additionally, the membrane may also be detachably or permanently glued in the valve arrangement, so that it can only be removed by pulling out, detaching or cutting out.

It can also be provided that the valve arrangement comprises a mechanically opening and closing valve. Such an additional valve may be formed in the manner according to the prior art. It can thus be achieved that the valve device can be switched on and switched on at least in a direction of flow, either as a function of pressure or as a result of external actuation. In some applications, where venting is desired only when the underpressure or overpressure exceeds a certain threshold, the auxiliary valve serves to maintain this threshold. The invention further comprises the use of a gas-permeable membrane valve assembly in a piping system of a hot beverage machine between a water storage tank and a brewing chamber as a pressure equalization valve.

The principle of the invention will be explained in more detail below with reference to a drawing by way of example. In the drawing show:

1 shows a schematic structure of a first embodiment of a hot beverage machine according to the invention, Figure 2 shows a schematic structure of a second embodiment of a hot beverage machine according to the invention,

Figure 3 is a sectional view of an embodiment of a valve assembly for

Use within the scope of the invention.

In principle, a hot beverage machine 1, which is designed according to Figure 1 as Päd- or Mehrgetränkemaschine, a water storage tank 3, the fresh water provides, which passes through a first liquid line 9a through a flow meter 1 1 and a pump 13 in a heater 15. For this purpose, the water storage tank 3 is connected in the present embodiment via a docking valve 5 with a cleaning sieve 7 with the first liquid line 9a.

The pump 13 is also designed as a backstop, so that the fresh water is not promoted by the pressure due to its heating in the heater 15 when the pump 13 is not in the water storage tank 3, but in the direction of a brewing chamber 23. Between the pump 13 and the heater 15, a pressure-dependent opening pressure relief valve 27 is arranged, which derives a possibly resulting pressure upstream of the heater 15 via a return line 29, bypassing the pump 13 in the water storage tank 3. It can also be switched independently of pressure by an actuator. For example, in the event of a defect in the heating device 15, residual liquid can be removed via the return line 29 before the start of maintenance. In the illustrated construction, however, it is used exclusively for pressure-dependent overpressure reduction due to, for example, calcification-related pressure disturbances in the heater 15th

Upstream of the heating device 15, a first temperature sensor 17a, downstream of the heating device 15 in a second liquid line 9b, a second temperature sensor 17b is arranged. The two temperature sensors 17a, 17b serve to detect the input and the output temperature of the water passed through, which are detected as input values for a control (not shown) of the heating power of the heater 15. Downstream of the second liquid line 9b immediately before the brewing chamber 23, a backstop 21 is positioned. It prevents a pressure equalization by suction of air from the brewing chamber takes place at a negative pressure in the second liquid line 9b This would namely the risk of contamination of the second liquid line 9b with Brühresten. Between the heating device 15 and the brewing chamber there is a valve arrangement 19a, which serves to equalize the pressure of the line system consisting of the first liquid line 9a and the second liquid line 9b. The valve assembly 19a according to the invention comprises a gas-permeable membrane. For a beverage preparation, the pump 13 fresh water from the water storage tank 3 in the heater 15. There, it is heated and fed to the brewing chamber 23. For an exact filling quantity or dosage of the brewing water provides the flow meter 1 1, the required temperature for successful preparation of the drink monitor the two temperature sensors 17a, 17b. At the end of a brewing process, the pump 13 turns off the water feed, while the heater 15 continues to run. The still in the heater 15 located water is quickly converted into steam due to the lack of cool inflowing water and causes a vapor pressure, which presses the liquid residues downstream of the heater 15 in the second liquid line 9b through the brewing chamber 23 in a provided cup 25. The vapor pressure also rinses out liquid residues of a beverage capsule in the brewing chamber 23 or dries in the brewing chamber 23 located Brühreste. A dripping when removing a used beverage capsule or from scraps can be largely avoided, which the operation of the hot beverage machine simplified. The remaining vapor pressure, which is still present in the second liquid line 9b after flushing the brewing chamber, is reduced in the further sequence via the valve arrangement 19a. This is due to the membrane in the valve assembly 19a successively and without a certain pressure difference threshold between the pressure in the second liquid line and would be overcome outside.

After completion of the beverage preparation operation, the heater 15 is turned off, so that the second liquid line 9 b cools downstream of the heater 15. The volume of the air and possibly remaining liquids is reduced, as a result of which a negative pressure is created in the two liquid lines 9a, 9b. So that the negative pressure no liquid or substrate residues from the brewing chamber 23 sucks into the liquid line 9b and further into the heater 15, the check valve 21 prevents pressure equalization via the brewing chamber 23. It can, for. B. may be formed as an elastic slotted membrane. Due to aging or manufacturing tolerances, however, their function may suffer, so that they are no longer completely airtight. However, a pressure equalization from the brewing chamber 23 is additionally avoided by the valve arrangement 19 a, due to which a local pressure equalization takes place away from the brewing chamber. Thus, if a negative pressure builds up in the second liquid line 9b, it is degraded early on via the valve arrangement 19a functioning as a vacuum valve.

Figure 2 shows a second embodiment of the invention, which is in principle almost identical to that shown in Figure 1 and differs only in the placement of the valve assembly: Instead of the valve arrangement 19a in Figure 1, which is arranged in the second liquid line 9b downstream of the heater 15 Here, an identical valve arrangement 19b is placed upstream of the heater 15 in the first liquid line 9a.

The placement of the valve assembly 19b at this point causes negative pressure, there is degraded, where otherwise due to the negative pressure fresh water from the water storage tank 3 in the direction of the heater 15 would be promoted. The negative pressure arises when the conduit system cools down after a brewing process and, for example, condenses water vapor. Fresh water that has entered the heater due to the negative pressure, would no longer be detected by the flow meter 1 1 in the next brewing process and the heater 15 would pass unheated. The result would be a thinner, and colder drink whose temperature is below the actually desired. The compensation of the negative pressure in the region of the liquid line 9a, however, avoids that fresh water enters the liquid line 9a and does not penetrate to the heating device 15.

The valve arrangement 19b, just like the valve arrangement 19a from FIG. 1, comprises a gas-permeable membrane. FIG. 3 shows a sectional view of a possible construction of a valve arrangement 19, as may be realized, for example, in the embodiments according to FIGS. 1 and 2 as valve arrangement 19a or 19b.

The valve assembly 19 (Figure 3) comprises a cylindrical valve housing 31, consisting of a lower part 35 and an upper part 33, which are releasably connected to each other. The connection consists of a clip closure whose elements are not shown in the sectional view. Instead of a clip closure, for example, a screw cap, such as a screw thread or a bayonet lock can be used. In a circumferential clamping region 41, which is located between the upper part 33 and the lower part 35, a gas-permeable membrane 39 is clamped from water-repellent coated PTFE material. The valve arrangement 19 is attached to a hose 37 of a line system in the region of an opening 43 of the hose 37.

If there is a higher pressure in the hose 37 than outside the hose 37, then gas is guided through the gas-permeable membrane 39 in an outlet direction O, whereby the pressure in the interior of the hose 37 is reduced. If there is a negative pressure in the hose 37, gas is passed through the gas-permeable membrane 39 in an inlet direction I, whereby the negative pressure in the interior of the hose 37 is reduced. A pressure equalization, as desired, for example, in the embodiments according to Figures 1 and 2, that is possible in both directions.

The water-repellent coating of the membrane 39 also ensures that no water can settle on it permanently, causing lime deposits can be largely avoided. In addition, the water that runs off also carries other entrained solid particles with it. The pores of the membrane 39 are thus largely protected from contamination.

The membrane 39 is removably secured by the clamping between the upper part 33 and the lower part 35, because by opening the clip of the valve assembly, the upper part 33 can be removed from the lower part 35 and the membrane 39 are released for removal. If required, the membrane 39 can additionally be fixed on the upper part 33 and / or on the lower part 35 by means of a pressure-sensitive adhesive (not shown here). In such a case, it is further necessary to remove the adhesive 39 for removal of the membrane or to cut out the membrane 39.

In addition to the diaphragm 39, the valve arrangement may also comprise a mechanically operable valve (not shown here). As a result, it can be ensured, for example, that pressure equalization is enabled only in one direction and / or only above a certain threshold value of the pressure difference inside and outside of the hose 37.

Since the foregoing detailed valve arrangement and the hot beverage machine are exemplary embodiments, they may be readily modified by one skilled in the art to a wide extent without departing from the scope of the invention. In particular, the specific configuration of the closure mechanism of the valve arrangement or the type of membrane and the arrangement of the valve arrangement within the conduit system can take place in a different form from those described here. Likewise, the hot beverage machine can be configured in another form or provided for other preparation functions. In addition, the arrangement of individual functional elements to each other within the hot beverage machine can be modified and designed in a variety of ways, if this is necessary for reasons of space or designerischen reasons. Furthermore, the use of the indefinite article "on" or "one" does not exclude that the characteristics in question may also be present multiple times. LIST OF REFERENCE NUMBERS

1 hot beverage machine

3 water storage tank

5 docking valve

7 cleaning sieve

9a first liquid line

9b second liquid line

1 1 flow meter

13 pump

15 heating device

17a first temperature sensor

17b second temperature sensor

19, 19a, 19b valve arrangement

21 backstop

23 brewing chamber

25 cup

27 pressure relief valve

29 return line

31 valve housing

33 top part

35 lower part

37 hose

39 membrane

41 clamping area

43 opening

I inlet direction

o outlet direction

Claims

A domestic hot beverage machine (1) comprising a water storage tank (3), a heater (15) and a brewing chamber (23) interconnected by a conduit system (9a, 9b) and a valve assembly (19; 19a; 19b) a conduit section (9a; 9b) of the conduit system (9a, 9b), characterized in that the valve arrangement (19; 19a; 19b) comprises a gas-permeable membrane (39).

Hot beverage machine according to claim 1, characterized in that the valve arrangement (19; 19a; 19b) is arranged in a line section (9a) between the water storage tank (3) and the heating device (15).

Hot beverage machine according to claim 1, characterized in that the valve arrangement (19; 19a; 19b) is arranged in a line section (9b) between heating device (15) and brewing chamber (23).

Hot beverage machine according to one of the preceding claims, characterized in that the membrane (39) comprises a material made of PTFE.

Hot beverage machine according to one of the preceding claims, characterized in that the membrane (39) is water-repellent coated.

Hot beverage machine according to one of the preceding claims, characterized in that the membrane (39) is removably arranged in the valve arrangement (19; 19a; 19b).

Hot beverage machine according to claim 6, characterized in that the membrane (39) is clamped in the valve arrangement (19; 19a; 19b).

8. Hot beverage machine according to one of the preceding claims, characterized in that the valve arrangement (19; 19a; 19b) comprises a mechanically closing and opening valve.

9. Use of a gas-permeable membrane (39) comprehensive valve arrangement (19, 19a, 19b) in a line system (9a, 9b) of a hot beverage machine (1) between a water storage tank (3) and a brewing chamber (23) as a pressure equalization valve.