WO2020119963A1

WO2020119963A1 - Heating device for heating a liquid, in particular water, contained in a reservoir, and apparatus for preparing hot beverages, in particular coffee or tea, comprising such a heating device

Info

Publication number: WO2020119963A1
Application number: PCT/EP2019/074853
Authority: WO
Inventors: Jorgen Bodum
Original assignee: Pi-Design Ag
Priority date: 2018-12-11
Filing date: 2019-09-17
Publication date: 2020-06-18
Also published as: EP3893700A1; SG11202104922VA; AU2019395646A1; JP2022510896A; DE102018131823A1

Abstract

The present invention relates to a heating device (10) for heating a liquid, in particular water, contained in a reservoir (20), the heating device (10) comprising a base (12) comprising a base housing (14), a bulb socket (16) fastened to the base housing (14), a bulb (18) inserted or insertable into the bulb socket (16), the bulb (18) generating electromagnetic radiation for heating a liquid contained in a reservoir (20), a bulb housing (26) encompassing the bulb, fastened on the base housing (14) and comprising an opening (30) permeable to the electromagnetic radiation generated by the bulb (18), and an insulating layer (36) arranged between the base housing (14) and the bulb housing (26) for reducing the heat conduction between the base housing (14) and the bulb housing (26). Moreover, the present invention relates to an apparatus (50) for preparing hot beverages, in particular coffee or tea comprising such a heating device.

Description

Heating device for heating a liquid, in particular water, contained in a reservoir, and apparatus for preparing hot beverages, in particular coffee or tea, comprising such a heating device

The present invention relates to a heating device for heating a liquid, in particular water, contained in a reservoir.

Beyond that the present invention is directed to an apparatus for preparing hot beverages, in particular coffee or tea, comprising such a heating device.

When preparing hot beverages such as coffee or tea there is the need to heat up water up to or near to the boiling point in order to extract flavoring agents included in coffee powder or tea leaves. In probably the simplest way of preparing coffee or tea the infusible material such as the coffee powder or the tea leaves is filled in a pot and poured over with hot water. After a certain time enough flavoring agents are extracted so that the coffee or tea is ready to drink.

One disadvantage of this way of preparing coffee or tea is that the infusible material is still included in the hot beverage. Although the infusible material is settling on the bottom of the drinking vessel there is a certain probability that the infusible material is transported into the mouth of the person upon drinking the beverage. The presence of

infusible material in the mouth is considered as unpleasant and may significantly reduce the drinking pleasure.

As a countermeasure the infusible material is separated from the beverage by filters. In particular in the preparation of coffee one-way-filters are used. However, these filters are difficult to handle after use and cause a higher environmental footprint compared to reusable filters. However, to employ reusable filters the apparatuses for preparing hot beverages require a special design. One such design is the so-called siphon-coffee maker using the siphon principle. A flask-shaped reservoir is disposed on a heating device. A container is disposed over the reservoir and has an open bottom to which a water feed tube is secured. The water feed tube is inserted into the reservoir to enable the air-tight communication between the reservoir and the container. The upper open end of the water feed tube is covered by a reusable filter.

To prepare coffee using the above-described siphon coffee maker, a desired amount of water and coffee powder is supplied into the reservoir and the container, respectively. The water is heated by the heating device up to or near to the boiling point. Upon heating the water the aerial pressure in the reservoir is increasing so that the hot water is fed to the container through the water feed tube and the filter. The hot water is mixed with the coffee powder received by the

container. Thereafter, when the heating device is switched off or the reservoir removed from the heating device the reservoir cools down and the aerial pressure therein is decreased, whereby the hot water mixed with coffee powder in the

container is filtered by the filter and sinks back into the reservoir through the water feed tube. The container is then removed from the reservoir and coffee obtained in the

reservoir is poured into a drinking vessel.

The heat required to heat the water may be provided by fuel such as spirit or natural gas, e.g. butane. However, the handling of corresponding heating devices is difficult and may lead to explosions and fires. An alternative way to provide the heat is to use electrical energy which is easier to handle. Such a heating device is disclosed in US 4 841 849 A. The heating device may include a conventional cooking plate. Alternatively, the heating device may include a bulb such as an infrared or halogen bulb that provide the heat. Such a device is disclosed in JP 2001 078889 A, KR 10 2013 0120289 A1 and KR 10 2012 0085494 A. Such heating devices comprise a base having a base housing to which a bulb socket is fastened. The bulb is encompassed by a bulb housing that is fastened on the base housing. Due to the heat produced upon the operation of the bulb the bulb housing is significantly heated. The heat is transferred to the base housing. As a result the user may burn her or his hand when inadvertently touching the bulb housing or the base housing. To reduce the risk of injury the devices disclosed in KR 10 2013 0120289 A1 and KR 10 2012 0085494 A are equipped with a fan that removes the heat from the bulb housing and the base housing. However, the use of a fan increases the complexity and the energy consumption of the heating device.

It is one task of one embodiment of the present invention to present a heating device of the type described above which is easy to manufacture, has a low energy consumption and

effectively reduces the risk of injury during operation.

Furthermore, an embodiment of the present invention has the object to provide an apparatus for preparing hot beverages that can be operated with such a heating device.

The task is solved by the features specified in claims 1 and 14. Advantageous embodiments are the subject of the dependent claims . One embodiment of the invention relates to a heating device for heating a liquid, in particular water, contained in a reservoir, the heating device comprising

- a base comprising a base housing,

- a bulb socket fastened to the base housing,

- a bulb inserted or insertable into the bulb socket, the bulb generating electromagnetic radiation for heating a liquid contained in a reservoir,

- a bulb housing encompassing the bulb, fastened on the base housing and comprising an opening permeable to the electromagnetic radiation generated by the bulb, and

- an insulating layer arranged between the base housing and the bulb housing for reducing the heat conduction between the base housing and the bulb housing.

The electromagnetic radiation can leave the bulb housing through the opening and reach the reservoir and the liquid contained therein, thereby enabling the heat transfer between the bulb and the liquid.

The insulating layer arranged between the base housing and the bulb housing reduces or even blocks the heat conduction between the bulb housing and the base housing. The heat generated by the operation of the bulb and absorbed by the bulb housing will not or only to a minimal extend be

transferred to the base housing. As a result the temperature of the base housing can be kept at a level that is harmless to a user. The risk of burning of the user's hands upon touching the base housing is significantly reduced.

According to one embodiment the bulb housing is fastened to the base housing by a number of first screws, the insulating layer being arranged such that it is compressed upon fastening of the first screws. In this embodiment the way the insulating layer is fastened is simple. As the bulb housing has to be fastened to the base housing anyway, in this embodiment the first screws not only fasten the bulb housing to the base housing but at the same time also fix the insulating layer.

The manufacturing process of the heating device is kept simple and the number of parts kept low.

In a further embodiment the insulating layer has a number of holes through which the first screws can be passed. In this embodiment the first screws not only fix the insulating layer to the heating device by friction but also by a form closure. Thus the position of the insulating layer is also fixed even in case the first screws are not strongly tightened.

A further embodiment is characterized in that the insulating layer is made of a first thermoplastic or a first elastomer, in particular a silicone elastomer. The first thermoplastic may be polystyrene or polypropylene. Silicone, polystyrene and polypropylene have a low thermal conductivity (< 0.15 W/ (m *

K) ) and a melting point (> 70°C) sufficiently high for this application. In particular silicone has a very high melting point of above 200°C. At the same time the material costs are acceptably low. Alternatively ceramics, cork or glass-fiber enforced plastic could also be used as they have similar properties regarding the thermal conductivity and the melting point as the materials previously discussed.

According to another embodiment the heating device comprises a heat protection unit encompassing the bulb housing. As

mentioned above, the bulb housing absorbs heat during the operation of the bulb. As a consequence there is the risk that the user burns her or his hand upon touching the bulb housing. The heat protection unit arranged radially outwards of the bulb housing prevents the user from being able to touch the bulb housing. The operational safety of the heating device is increased .

In a further embodiment the heat protection unit is fastened to the bulb housing omitting the opening. In this embodiment no further fastening structures are needed so that the design of the heating device can be kept simple. By omitting the opening the structure does not aggravate the heat transfer between the bulb and the liquid contained in the reservoir.

A further embodiment is characterized in that the heat protection unit is fastened to the bulb housing by second screws. The fastening is realized in a simple and cost efficient way. The use of screws enables the simple

replacement of the heat protection unit.

According to another embodiment the heat protection unit is fastened to the bulb housing leaving a gap between the heat protection unit and the base housing. The gap can be kept small, e.g. below 5 mm. As a result there is no contact between the heat protection unit and the base housing. The heat conduction between the heat protection unit and the base housing is interrupted so the heat that may be transferred between the heat protection unit and the base housing is minimized.

In a further embodiment the heat protection unit comprises a number of recesses. As mentioned above the heating device may be used in combination with an apparatus for preparing hot beverages using the siphon principle. Such apparatuses often comprise a holding device to position the reservoir above the heating device. The feet of the holding device may extend into the recesses. In this embodiment the heat protection unit is not an obstacle for holding devices. There is no need for providing holding devices particularly tailored to the present heating device. Instead, commercially available holding devices may be used.

A further embodiment is characterized in that the heat

protection unit is made of a second thermoplastic or a second elastomer, in particular a silicone elastomer. The second thermoplastic may be polystyrene or polypropylene. Silicone, polystyrene and polypropylene have a low thermal conductivity (< 0.15 W/ (m * K) ) and a sufficiently high melting point (> 70°C) sufficiently high for the present application. In particular silicone has a very high melting point of above 200°C. At the same time the material costs are acceptably low.

According to another embodiment the first thermoplastic and the second thermoplastic are the same, or the first elastomer and the second elastomer are the same. As the insulating layer and the heat protective unit have similar functions, in particular to reduce heat conduction, they may both be made of the same material which facilitates the manufacturing process and reduce the costs.

A further embodiment the heating device comprises a

reinforcing structure for reinforcing the heat protection unit. In particular in case the heat protection unit is made of an elastomer it may be difficult to design the heat

protecting unit in a self-supporting way. Using a reinforcing structure the freedom of design of the heat protection unit is increased . According to another embodiment the heating device comprises switch-off means interrupting the power supply to the bulb after a preset time. Switch-off means may be integrated into a switch by which a user may turn on and off the heating device. The switch-off means may be configured to automatically switch off the heating device after a preset time, e.g. 15 or 30 minutes in case no contrary command is received. In this embodiment an over-heating is prevented which may damage the heating device. Moreover, the thermal load of the heating device is reduced, thereby increasing the durability of the heating device. Beyond that unnecessary energy consumption is reduced .

Another implementation of the invention is directed to

apparatus for preparing hot beverages, in particular coffee or tea, comprising

- a reservoir for containing water,

- a container for receiving coffee powder or tea leaves or the like, the container connectable to the reservoir such that the container is arranged above the reservoir,

- the container having a water feed tube extending

downwardly from the bottom thereof into the reservoir when the container is connected to the reservoir, thereby providing a fluid communication between the reservoir and the container, and

- a heating device according to one of the preceding

embodiments positioned such that the opening is facing the reservoir.

The technical effects and advantages as discussed with regard to the present heating device equally apply to the apparatus. Briefly, the temperature of the base housing is kept at a certain level that is harmless to a user. The operational safety of the heating device and the apparatus for preparing hot beverages as a whole is increased.

In a further implementation the apparatus comprises a holding device connectable to the reservoir such that the reservoir is located above the heating device. By means of the holding device the reservoir may be located above the heating device.

It is not necessary to place the reservoir directly on the upper end of the heating device. Therefore, even ball-shaped reservoirs may be used. As initially mentioned apparatuses for preparing hot beverages using the siphon principle may also be run with heating devices using fuel. It is usually not

possible to place the reservoir directly on the burner of the heating device so a holding device is needed to locate the reservoir above the burner. The same equipment may thus be used in combination with the present heating device so no specially designed equipment is needed.

The present invention is described in detail with reference to the drawings attached wherein

Figure 1 is a perspective view of one embodiment of a heating device for heating a liquid according to the present invention,

Figure 2 is a sectional view through the heating device shown in Figure 1,

Figure 3 is an enlarged view of the detail C defined in Figure

2, Figure 4A is a side-sectional view through an apparatus for preparing hot beverages comprising the heating device shown in Figures 1 to 3, and

Figure 4B is a perspective view of the apparatus shown in

Figure 4A.

Reference will now be made in detail to one present exemplary embodiment of the disclosure, example of which is illustrated in the accompanying drawings. Whenever possible, the same or similar reference numbers will be used throughout.

In Figures 1 and 2 a heating device 10 according to one embodiment of the invention is shown by means of a perspective view and a sectional view, respectively. The heating device 10 comprises a base 12 having a base housing 14 to which a bulb socket 16 is fastened. A bulb 18, in this case a halogen bulb 18, is inserted into the bulb socket 16. The bulb 18 provides electromagnetic radiation which is used to heat up a liquid comprised in a reservoir 20 (see Figures 4A and 4B) . The bulb 18 can be switched on and off by a switch 22 which is also indirectly fastened to the base housing 14. The wiring for supplying electrical energy to the bulb 18 is not shown. The switch 22 comprises switch-off means 24 to turn off the bulb 18 after a preset time, e.g., 15 or 30 minutes.

The bulb 18 is surrounded by a bulb housing 26 which is fastened to the base housing 14 by means of first screws 28.

The bulb housing 26 has an opening 30 which is permeable to the electromagnetic radiation generated by the bulb 18. In the embodiment shown the opening 30 is covered by a glass plate 32 that is also fastened to the bulb housing 26. The opening 30 and the glass plate 32 are arranged near a free end 34 of the bulb 18.

As in particular visible in Figure 3 an insulating layer 36 is arranged between the base housing 14 and the bulb housing 26. The insulating layer 36 comprises holes 38 through which the first screws 28 can be passed. The insulating layer 36 has a thickness d of between 5 and 10 mm, in particular between 5 and 7 mm. The insulating layer 36 is made of a first

thermoplastic like polystyrene or polypropylene or a first elastomer, in particular a silicone elastomer. When the first screws 28 are fastened the insulating layer 36 is compressed so that the insulating layer 36 is fixed relative to the base housing 14 and the bulb housing 26.

Beyond that the heating device 10 is equipped with a heat protection unit 40 that is arranged around the bulb housing 26. In the shown embodiment the protection unit is tubular and is fastened to the bulb housing 26 by means of second screws 42. The heat protection unit 40 is not covering the opening 30 of the bulb housing 26. Moreover, the heat protection unit 40 is fastened to the bulb housing 26 such that a gap 44 of 1 to 5 mm is formed between the heat protection unit 40 and the base housing 14. As in particular visible in Figure 1 the heat protection unit 40 further comprises a number of recesses 46 in which the distance between the heat protection unit 40 and the base housing 14 is significantly bigger than within the gaps 44. The distance may be between 10 and 25 mm. The heat protection unit 40 is made of a second thermoplastic or a second elastomer, in particular a silicone elastomer. The first thermoplastic or the first elastomer the insulating layer 36 is made of and the second thermoplastic or the second elastomer the heat protection unit 40 is made of are the same. The heating device 10 comprises a reinforcing structure 48 for reinforcing the heat protection unit 40. The reinforcing structure 48 of the embodiment shown is annular and located radially inwards of the heat protection unit 40. The second screws 42 run through the reinforcing structure 48. The reinforcing structure 48 is made of metal.

In Figures 4A and 4B an apparatus 50 for preparing hot

beverages, in particular coffee or tea, is shown by means of a side-sectional view and a perspective view, respectively. The apparatus 50 uses the siphon principle and comprises the reservoir 20 as already mentioned into which a desired amount of water can be poured. Moreover, the apparatus 50 comprises a container 52 to which an infusible material (not shown) like coffee powder or tea leaves may be supplied. The container 52 comprises a water feed tube 54 that is inserted into the reservoir 20 in an air-tight manner. To this end, a sealing 56 is arranged between the reservoir 20 and the container 52. The upper open end of the water feed tube 54 is covered by a reusable filter 58. As in particular evident from Figure 4A the filter 58 is connected to a spring 60 having a grip section 62. By pulling the grip section 62 the filter 58 can be inserted into the water feed tube 54 and thereby positioned relative to the container 52 as desired.

To expose the water received in the reservoir 20 to the electromagnetic radiation generated by the bulb 18 of the heating device 10 the reservoir 20 has to be positioned close to the opening 30 of the bulb housing 26. For that purpose the apparatus 50 comprises a holding device 64 connectable to the reservoir 20. The holding device 64 is placed on the upper surface 66 of the base housing 14. Referring to Figure 4B the feet 68 of the holding device 64 extend through the recesses 46 of the heat protection unit 40.

To prepare coffee a desired amount of water and coffee powder is supplied into the reservoir 20 and the container 52, respectively. The water is heated by the heating device 10 to or near to the boiling point. Upon heating the aerial pressure in the reservoir 20 is increasing so that the hot water is fed to the container 52 through the water feed tube 54 and the filter 58. The hot water is mixed with the coffee powder in the container 52. As soon as the heating device 10 is switched off or the reservoir 20 removed from the heating device 10 the reservoir 20 cools down and the aerial pressure therein is decreased, whereby the hot water mixed with coffee powder in the container 52 is filtered by the filter 58 and sinks back into the reservoir 20 through the water feed tube 54. The container 52 is then removed from the reservoir 20 and coffee obtained in the reservoir 20 is poured into a drinking vessel.

In operation of the heating device 10 the electromagnetic radiation generated by the bulb 18 not only heats the water contained in the reservoir 20 but is also absorbed by the bulb housing 26 (see Figure 2) . The insulating layer 36 prevents the heat to be transferred to the base housing 14. As a result the temperature of the base housing 14 and in particular of the upper surface 66 of the base housing 14 is kept at a level harmless to a user. Moreover, the thermal load to the

components located inside the base housing 14 like the switch 22 or located on the upper surface 66 of the base housing 14 like the holding device 64 is kept low. As already mentioned the switch 22 and the switch-off means 24 are indirectly fastened to the base housing 14. As a result they are almost unaffected by the temperature of the base housing 14 as there is no direct heat conduction between the base housing 14 and the switch 22 or the switch-off means 24, respectively.

Further, the heat protection unit 40 prevents the direct contact of a user's hand with the bulb housing 26 reducing the risk of injury. The switch-off means 24 turn off the bulb 18 after a preset time, e.g. after 15 minutes, in case no other command is received. Thereby over-heating is prevented which may damage the heating device 10. Moreover, the thermal load of the heating device 10 is reduced, thereby increasing the durability of the heating device 10. Beyond that unnecessary energy consumption is reduced.

Reference signs

10 heating device

12 base

14 base housing

16 bulb socket

18 bulb

20 reservoir

22 switch

24 switch-off means 26 bulb housing

28 first screw

30 opening

32 glass plate

34 free end

36 insulating layer 38 hole

40 heat protection unit 42 second screw

44 gap

46 recess

48 reinforcing structure 50 apparatus

52 container

54 water feed tube 56 sealing

58 filter

60 spring

62 grip section

64 holding device

66 upper surface

68 feet

d distance

Claims

1. Heating device (10) for heating a liquid, in particular water, contained in a reservoir (20) , the heating device ( 10 ) comprising

- a base ( 12 ) comprising a base housing ( 14 ) ,

- a bulb socket (16) fastened to the base housing ( 14 ) ,

- a bulb (18) inserted or insertable into the bulb socket (16), the bulb (18) generating electromagnetic radiation for heating a liquid contained in a reservoir (20) ,

- a bulb housing (26) encompassing the bulb, fastened on the base housing ( 14 ) and comprising an opening (30) permeable to the electromagnetic radiation generated by the bulb (18), and

- an insulating layer (36) arranged between the base

housing ( 14 ) and the bulb housing (26) for reducing the heat conduction between the base housing ( 14 ) and the bulb housing (26) .

2. Heating device ( 10 ) according to claim 1 ,

characterized in that the bulb housing (26) is fastened to the base housing ( 14 ) by a number of first screws (28) , the insulating layer (36) being arranged such that it is compressed upon fastening of the first screws (28) .

3. Heating device ( 10 ) according to claim 2 ,

characterized in that the insulating layer (36) has a number of holes (38 ) through which the first screws (28) can be passed .

4. Heating device ( 10 ) according to one of the preceding

claims , characterized in that the insulating layer (36) is made of a first thermoplastic or a first elastomer, in particular a silicone elastomer.

5. Heating device (10) according to one of the preceding

claims ,

characterized in that the heating device (10) comprises a heat protection unit (40) encompassing the bulb housing (26) .

6. Heating device ( 10 ) according to claim 5,

characterized in that the heat protection unit (40) is fastened to the bulb housing (26) omitting the opening (30) .

7. Heating device ( 10 ) according to claim 6,

characterized in that the heat protection unit (40) is fastened to the bulb housing (26) by second screws ( 42 ) .

8. Heating device ( 10 ) according to claims 6 or 7,

characterized in that the heat protection unit (40) is fastened to the bulb housing (26) leaving a gap (44) between the heat protection unit (40) and the base housing (14) .

9. Heating device ( 10 ) according to claims 5 to 8,

characterized in that the heat protection unit (40) comprises a number of recesses (46) .

10. Heating device ( 10 ) according to one of the claims 5 to 7, characterized in that the heat protection unit (40) is made of a second thermoplastic or a second elastomer, in

particular a silicone elastomer .

11. Heating device (10) according to claims 4 and 10, characterized in that

- the first thermoplastic and the second thermoplastic are the same, or

- the first elastomer and the second elastomer are the

same .

12. Heating device ( 10 ) according to one of the claims 5 to 11 , characterized in that the heating device (10) comprises a reinforcing structure (48) for reinforcing the heat

protection unit (40) .

13. Heating device ( 10 ) according to one of the preceding

claims ,

characterized in that the Heating device (10) comprises switch-off means (24 ) interrupting the power supply to the bulb (18) after a preset time .

14. Apparatus (50) for preparing hot beverages , in particular coffee or tea, comprising

- a reservoir (20 ) for containing water;

- a container (52 ) for receiving coffee powder or tea

leaves or the like, the container ( 52 ) connectable to the reservoir (20) such that the container (52 ) is arranged above the reservoir (20),

- the container ( 52 ) having a water feed tube (54 )

extending downwardly from the bottom thereof into the reservoir (20) when the container ( 52 ) is connected to the reservoir (20) , thereby providing a fluid

communication between the reservoir (20) and the

container ( 52 ) , and - a heating device (10) according to one of the preceding claims positioned such that the opening (30) is facing the reservoir (20) .

15. Apparatus according to claim 14 ,

characterized in that the apparatus comprises a holding device ( 64 ) connectable to the reservoir (20) such that the reservoir (20) is located above the heating device (10).