Hot beverage preparation device

Abstract

The invention relates to a hot beverage preparation device, in particular a coffee machine, having a water heater for heating and storing hot water and / or hot steam for the preparation of a hot beverage, having a cold water inlet, a storage container with a heater and a hot water and / or steam outlet, wherein it is provided that the storage container is at least partially provided with or at least partially surrounded by a vacuum insulation. By means of the vacuum insulation the heat losses of the water heater can be reduced.

Description

Technical Field

[0001] The present invention relates to a hot beverage preparation apparatus, particularly a coffee machine, having a water heater for heating and storing hot water or steam for preparing hot beverages, the water heater having a cold water inlet, a storage container with a heater, and a hot water or steam outlet. Background Technology

[0002] In automatic coffee machines, a water heater is typically used to store the hot water needed for beverage preparation. This water heater stores water at a temperature below 100 degrees Celsius, usually around 90°C. Often, there are even separate water heaters for hot water and steam. The waste heat inevitably generated when the water heater produces hot water must be dissipated to prevent overheating inside the machine. Excessive temperatures inside an automatic coffee machine can lead to temporary component failure, long-term malfunctions due to premature aging, and fluctuations in product quality. Thermal problems can occur, especially with very compact machines where there is insufficient space to dissipate waste heat. Active cooling of the automatic coffee machine is usually necessary using a fan to dissipate waste heat during hot water preparation. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide a hot beverage preparation apparatus that improves temperature management and achieves a very compact structure.

[0004] The objective is achieved through the features of Scheme 1. Advantageous design schemes are derived from subordinate schemes.

[0005] In the hot beverage preparation apparatus of the type described above, according to the present invention, the storage container is at least partially provided with a vacuum insulation structure or at least partially surrounded by a vacuum insulation structure.

[0006] Compared to conventionally insulated water heaters, vacuum insulation significantly reduces heat loss. Low waste heat positively impacts the quality, shelf life, and grinding characteristics of fresh coffee beans, which are typically stored at the top of the equipment and thus particularly susceptible to rising waste heat. By reducing waste heat, active cooling or ventilation of the equipment can be eliminated, or at least cooling power can be significantly reduced. Due to the reduced waste heat in vacuum-insulated water heaters, energy consumption is lowered, thereby improving energy efficiency and reducing operating costs and CO2 emissions.

[0007] In its simplest form, the outer wall of the water heater's storage container can be designed, at least partially, as a double-walled structure, with the double-walled area enclosing a vacuum space. This allows the water heater to be compactly constructed and generate less waste heat.

[0008] Alternatively, to achieve vacuum insulation, the storage container can be housed within an outer shell that is at least partially double-walled, the double-walled area of ​​which encloses a space for vacuum removal. This allows the use of a conventional water heater, which can then be removed from the vacuum-insulated shell and replaced for repair and replacement in case of malfunction.

[0009] In both cases, a non-vacuum insulated cover can be fitted to the double-walled storage container or the double-walled outer shell, through which the electrical and / or hydraulic connections of the water heater pass. This allows for a simpler implementation of the connection without the need for complex passages through a vacuum casing. The non-vacuum insulated cover can, for example, be fitted with an insulated structure made of insulating material in a conventional manner.

[0010] Within the scope of this invention, a water heating device for providing and storing steam can also be considered a water heater, wherein the steam, in normal operation, comprises a certain volume of steam under pressure and a certain volume of hot water that has not yet evaporated under the existing temperature and pressure conditions. Water heaters within the scope of this invention can also be used to simultaneously provide hot water and steam and have both a hot water outlet and a steam outlet.

[0011] In a preferred embodiment of the invention, hot water with a storage temperature above 100°C is stored, and during beverage preparation, cold water is added to bring the preparation temperature below 100°C. To this end, the storage container of the water heater is designed as a pressure vessel, in which hot water is stored at a temperature above 100°C during operation, and the hot water outlet is connected to a metering valve for metering the addition of cold water, so that cold water is added to the hot water upon output, thereby outputting mixed water at a temperature below 100°C for beverage preparation.

[0012] The use of water heaters that store hot water under pressure at temperatures above 100°C and incorporate cold water during extraction is essentially independent of vacuum-insulated water heaters and constitutes an independent inventive contribution. Here, although water heaters using vacuum insulation offer special advantages due to their higher storage temperatures, water heaters insulated using normal, conventional methods can also be used in principle.

[0013] By incorporating cold water, the amount of hot water provided for beverage preparation is increased, or in other words, the water heater can be designed more compactly while maintaining the same amount of hot water available for beverage preparation. Conventional water heaters experience significantly increased waste heat due to their higher storage temperatures. However, the vacuum insulation structure according to the invention significantly reduces waste heat, thus allowing for a compact design of the device despite higher storage temperatures without exceeding the device's internal operating temperature.

[0014] Here, the storage temperature can be selected to be above 110°C, preferably in the range of 110°C to 180°C, and particularly in the range of 120°C to 140°C.

[0015] Furthermore, it is preferable to incorporate cold water in an adjustable manner, wherein the metering valve for incorporating the cold water is designed as an adjustable valve, particularly a proportional valve, and the hot beverage preparation apparatus has a second temperature sensor for determining the temperature of the mixed water and a controller for adjusting the temperature of the mixed water by manipulating the metering valve. Thus, the output temperature of the hot water can be adjusted to different values ​​depending on the desired beverage. For example, less cold water can be incorporated for distilled coffee, while more cold water can be incorporated for brewing green tea.

[0016] A static mixer, particularly a spiral mixer, can be installed between the metering valve and the temperature sensor to mix the cold and hot water flows. This mixer ensures rapid and thorough mixing of the water flows. The temperature of the mixed water after mixing can then be measured directly after the mixer as a control variable. This allows for a particularly compact design.

[0017] The heater of the water heater can be suitably configured as a heating spiral filament disposed within the storage container. This allows the water heater to have a particularly compact structure. In particular, the heater can be configured as a spiral tubular heater in such a way that the heating spiral filament extends inside a spiral heating tube, which is preferably filled with magnesium oxide powder to electrically insulate the heating spiral filament.

[0018] Within the scope of this invention, not only can a single vacuum-insulated water heater be installed, but multiple water heaters can also be installed, such as one water heater configured to generate steam and another water heater configured to generate hot water, and both water heaters are respectively provided with or surrounded by a vacuum-insulated structure. It is also possible to use more than two water heaters, for example, to allow for the simultaneous extraction of two beverages. Attached Figure Description

[0019] Other advantages and design features of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

[0020] in: Figure 1 shows a first embodiment of a vacuum-insulated water heater. Figure 2 shows an embodiment of a water heater housed in a vacuum-insulated casing. Figure 3 shows the water circuit diagram of a hot beverage preparation device with two vacuum-insulated water heaters, one for providing hot water and the other for providing steam. Figure 4 shows a time curve of the hot water temperature inside the water heater. The curve also shows a record of the cooling curve to assess the quality of the vacuum insulation. Figure 5 shows a water circuit diagram of a hot beverage preparation apparatus according to another embodiment, in which a static mixer is additionally provided for mixing cold water supplied via a mixing valve with hot water extracted from a water heater. Detailed Implementation

[0021] According to the present invention, a water heater 10 used in a hot beverage preparation apparatus, such as, for example, a coffee machine, is... Figure 1 The image is shown in cross-sectional view. The water heater 10 includes a storage container 11, which has double walls in the lower region and has an inner outer wall 11a and an outer outer wall 11b. A space 12 exists between the outer walls, which is evacuated, thus providing vacuum insulation for the outer walls 11a and 11b. In the upper region, the water heater 10 has a cover 13 designed as a single-walled structure, through which electrical and hydraulic conductors extend. Inside the storage container 10 is a spiral tubular heating element 14. The tubular heating element has two electrical connectors 14a and 14b, which extend outward through corresponding conductors in the cover 13. Furthermore, the water heater has multiple free conductors 15, 16, and 17. These conductors allow connection to supply and outlet pipes, as well as measuring instruments such as pressure gauges or thermometers. A vacuum valve 18 is provided in the lower region, through which the space 12 between the inner and outer outer walls 11a and 11b is evacuated.

[0022] exist Figure 2 A second embodiment of the vacuum-insulated water heater 10 is also shown in a partially cut-away view. The water heater 10 includes a storage container 11', which is conventionally constructed with a single-walled structure. A spiral tubular heating element 14 is disposed within the storage container, the heating element having two electrical connectors 14a and 14b, which extend outwards through a conductive section located in the upper region of the storage container 11'. Other conductive sections are used to connect supply and outlet pipes and, if necessary, to connect measuring instruments, with only one conductive section 15... Figure 2 It is visible in the middle.

[0023] The storage container 11' is located within a vacuum-insulated outer shell 20, the lower region of which is designed with double walls, having an inner outer wall 21a and an outer outer wall 21b. A space 22 exists between the outer walls, which has been evacuated by a vacuum valve 28. In the upper region, the outer shell 20 is closed by a non-vacuum-insulated cover 23 through which electrical and hydraulic conductors extend. The cover 23 can be insulated in a conventional manner using insulating materials such as needle felt made of synthetic fibers, silicone foam, glass wool, or the like. The cover 23 can be opened for the installation or removal of the water heater 10 or for repair of the water heater, thereby allowing maintenance and replacement of the water heater 10 without the vacuum-insulated outer shell 20.

[0024] exist Figure 3 The diagram shows a so-called water circuit diagram of a coffee machine according to the invention, having two water heaters 10a and 10b, which, as previously described, are provided with or surrounded by a vacuum-insulated structure according to the invention. Water heater 10a is used to prepare and store hot water for preparing beverages, and water heater 10b is used to prepare and store steam for frothing milk, and contains a volume of water and a volume of steam in thermal equilibrium.

[0025] An assembly 30 is provided at the water inlet on the input side, connected to a connector for water supply or to a water container. This assembly includes a water filter 31, a shut-off valve 32, two check valves 33 connected sequentially, a water pump 34, and a third temperature sensor 35. The water pump 34 allows cold water to reach the inlet of the water heater 10a via a flow meter 36 and another check valve 37. The water in the water heater 10a is heated to a storage temperature of 120°C to 140°C. The temperature in the water heater 10a can be determined by a first temperature sensor 39 and can be adjusted by operating the heater 14 of the water heater 10a. A pressure relief valve 28 at the inlet of the water heater directs water from the water heater 10a to the outlet in case of overpressure. The hot water outlet of the water heater 10a leads to two valve blocks 41 and 42. A proportional valve 40 is provided between the inlet and outlet of the water heater 10a, which allows cold water to be mixed into the hot water from the water heater 10a. The temperature of the mixed water can be measured by the second temperature sensor 44, and the water temperature can be adjusted accordingly by operating the proportional valve.

[0026] Mixing hot water with cold water supplied via proportional valve 40 can be carried out in a flexible hose downstream of the hot and cold water junction. To achieve the fastest possible mixing of the two water streams, a static mixer 43, such as a spiral mixer, can be additionally provided, which thoroughly mixes the two streams. This is schematically illustrated in... Figure 5As shown in the diagram, a spiral mixer is a static mixer in which multiple 180° spiral structures, each deflected 90° relative to the others, are arranged sequentially within a tubular housing. Furthermore, the successive spiral structures have opposite directions of rotation. Each spiral structure divides the flowing liquid into two streams. These streams further divide into two streams at each transition point to the corresponding subsequent spiral structure and merge with the streams from the preceding spiral structure. This achieves thorough mixing of the liquid flow.

[0027] The hot water outlet of water heater 10a is connected to two valve blocks 41 and 42. Hot water for tea preparation can be output through valve 41a, and valve 41b can fill water heater 10b for steam preparation. Valve 41c is not used in this embodiment and can be used for other optional functions. The input of valve 41d is connected to the output of valve 41b and also leads to the hot water outlet, thus allowing simultaneous output of hot water and steam. Hot water can be output at beverage outlet 45 through valve 42a, which can be used, for example, for instant beverages or for blending coffee. Furthermore, valve 42a can be used to flush the output pipe from brewing assembly 52 to outlet 45. Valve 42b is not used in this embodiment and can be used, for example, for the "instant beverage" option.

[0028] In addition, a pipe leads from the hot water outlet of the water heater 10a to the brewing valve 51 in the brewing unit 50. The brewing unit 50 includes a brewing assembly 52 with a movable brewing piston that closes a cylindrical brewing chamber. The brewing chamber can be automatically filled with freshly ground coffee powder by two separate grinding mechanisms 53a and 53b for different types of coffee. When the brewing valve 51 is open, hot water flows from the water heater 10a under the pressure of the water pump 34 through the brewing assembly 52. ​​An adjustable back pressure valve 54 is provided at the output end of the brewing assembly 52, through which the flow rate of the freshly brewed coffee beverage can be adjusted. The freshly brewed coffee flows from here to the coffee machine's output head 45.

[0029] Steam for heating and, if necessary, frothing the milk is provided by water heater 10b. Steam pipe 61, leading to steam nozzle 62, can be opened via valve block 60 having two valves 60a and 60b connected in parallel. Air can be added to the steam during output via air pump 63 and check valve 64 to froth the milk. Furthermore, a fourth temperature sensor 65 can be provided on steam nozzle 62 to measure the temperature of the milk being heated or frothed by steam.

[0030] A pressure relief valve 66, a pressure gauge 67, and a fifth temperature sensor 68 are also provided at the steam outlet of the water heater 10b. The temperature inside the water heater 10b can be monitored by the first temperature sensor 69, and this temperature can be adjusted by correspondingly controlling the heater 14.

[0031] By utilizing the vacuum insulation structure of water heaters 10a and 10b according to the invention, a significant reduction in heating waste heat can be achieved, allowing the devices to be configured very compactly without thermal issues. Furthermore, the vacuum insulation enables the storage of hot water at higher temperatures, allowing for the addition of cold water to provide a larger volume of water at output. This allows for a more compact design of water heater 10a, or the preparation of larger quantities of hot beverages before the need for reheating.

[0032] The vacuum in the double-walled region of a vacuum insulation structure is typically below one millibar, preferably even below one microbar, and more preferably even below 0.1 µbar. Additionally, to achieve long-term vacuum stability, a so-called getter material can be introduced into the vacuum to absorb gases in the event of minimal leaks and when the material releases gas. The getter, or degassing agent, is a chemically reactive material used to maintain the vacuum for as long as possible. Gas molecules form compounds (oxides) with the atoms of the getter material on the surface of the getter, or the gas molecules are fixed by adsorption. Gas molecules can be "captured" in this way. Metals, such as barium alloys, aluminum alloys, or magnesium alloys, are suitable as getters; these metals can be heated after evacuation if necessary to cause the getter metal to evaporate.

[0033] A reflective film may be additionally introduced into the vacuum-vented spaces 12, 22, which further reduces the waste heat of the water heaters 10, 10'.

[0034] As already explained, the vacuum insulation structure can be part of the water heater and mechanically connected to it or form a unit with it, or the vacuum insulation structure can be designed as a separate component and the water heater can be enclosed within it.

[0035] exist Figure 4 The graph shown illustrates the recording of cooling curves, which can be used to evaluate the quality of vacuum insulation, and the graph shows the time curve of the hot water temperature inside the water heater.

[0036] To this end, additional software functions are implemented through a control device that can simultaneously operate the heater 14 and regulate the hot water temperature in the water heater 10. These software functions determine the insulation quality based on the cooling curves of the water heaters 10 and 10', which can be measured using first temperature sensors 39 and 69. This allows for the inspection of the vacuum insulation. If rapid cooling is detected, it can be concluded that the vacuum in the vacuum insulation structure is defective, and a corresponding error message can be generated, indicating that the vacuum insulation structure needs to be replaced or repaired. This information can be retrieved either from the device itself or through remote maintenance.

[0037] exist Figure 4 A temperature curve over time t is plotted using the first temperature sensor 39 or 69 of water heater 10b or 10b. After the heater is turned off, the temperature slowly decreases until it reaches the lower adjustment threshold. If this adjustment threshold is reached, heater 14 is turned on for a heating period H. The temperature then rises again to the upper adjustment threshold, or to the desired temperature in the water heater. A predetermined time period of 60 seconds is then waited until heater 14 has released all its heat energy to the hot water. The time period Δt is then measured, during which the temperature decreases by a predetermined temperature difference ΔT, which is 1°C in this embodiment. This cooling time is an indicator of the insulation performance of the vacuum insulation structure. If the cooling time of 1°C is lower than the minimum value for a good vacuum insulation structure, an error message is generated and reported to the monitoring center via data connection, indicating a possible malfunction in the vacuum insulation of water heater 10a or 10b, requiring inspection. This allows for a simple evaluation and confirmation of the vacuum insulation structure and the presence of defects in the vacuum. Alternatively, the time period between two heating periods H can also be recorded as the cooling time, that is, the time until the temperature drops to the lower adjustment threshold and heater 14 is reactivated.

Claims

1. A hot beverage preparation apparatus, the hot beverage preparation apparatus having at least one water heater for heating and storing hot water and / or hot steam for preparing hot beverages, the water heater having a cold water inlet, a storage container with a heater (14) and a hot water and / or steam outlet, Its features are, The storage container is at least partially provided with a vacuum insulation structure (12, 22) or at least partially surrounded by a vacuum insulation structure (12, 22); The hot beverage preparation apparatus has a control device set using program technology, which is connected to a first temperature sensor (39, 69) located inside the water heater for monitoring and / or adjusting the temperature of hot water or steam. The control device is configured to detect the cooling time after the heater (14) is turned off and generate an error message when the time is below a threshold, the error message indicating that the vacuum insulation has failed.

2. The hot beverage preparation apparatus according to claim 1, wherein, The outer walls (11a, 11b) of the storage container are at least partially constructed as double walls for vacuum insulation, and the double-walled regions of the outer walls enclose a space for vacuum discharge.

3. The hot beverage preparation apparatus according to claim 1, wherein, The storage container is housed in a shell (20) that is at least partially double-walled for vacuum insulation, wherein the double-walled regions (21a, 21b) of the shell enclose a space for vacuum removal.

4. The hot beverage preparation apparatus according to claim 2 or 3, wherein, The double-walled storage container (11') or the double-walled outer shell (20) has a non-vacuum insulated lid (13, 23) through which electrical and / or hydraulic connections (14a, 14b, 15, 16, 17) pass.

5. The hot beverage preparation apparatus according to claim 1, wherein, The storage container is designed as a pressure vessel in which hot water is stored at a temperature above 100°C during operation, and the hot water outlet is connected to a metering valve (40) for metering the addition of cold water so that cold water is added to the hot water at the output, thereby outputting mixed water at a temperature below 100°C for the preparation of beverages.

6. The hot beverage preparation apparatus according to claim 5, wherein, The storage container is configured to store hot water at temperatures above 110°C during operation.

7. The hot beverage preparation apparatus according to any one of claims 5 or 6, wherein, The metering valve (40) for adding cold water is designed to be adjustable, and the hot beverage preparation device has a second temperature sensor (44) for determining the temperature of the mixed water and a controller for adjusting the temperature of the mixed water by manipulating the metering valve (40).

8. The hot beverage preparation apparatus according to claim 7, wherein, A static mixer is provided between the metering valve (40) and the second temperature sensor (44) for mixing cold water flow and hot water flow.

9. The hot beverage preparation apparatus according to claim 1, wherein, The heater (14) is configured as a heating spiral wire disposed within the storage container.

10. The hot beverage preparation apparatus according to claim 9, wherein, The heating spiral wire extends inside the spiral-shaped heating tube.

11. The hot beverage preparation apparatus according to claim 1, wherein, The hot beverage preparation apparatus has a first water heater configured to generate hot water and a second water heater configured to generate steam, both of which are provided with or surrounded by a vacuum insulation structure (12, 22).

12. The hot beverage preparation apparatus according to claim 2 or 3, wherein, Insert air-absorbing material into the vacuum-vented space.

13. The hot beverage preparation apparatus according to claim 2 or 3, wherein, A reflective film is installed in the vacuum-vented space.

14. The hot beverage preparation apparatus according to claim 6, wherein, The storage container is configured to store hot water at temperatures ranging from 120°C to 140°C during operation.

15. The hot beverage preparation apparatus according to claim 10, wherein, The heating tube is filled with magnesium oxide powder to provide electrical insulation for the heating spiral wire.

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