JPH0329404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal filter which is removably connected to a motor shaft and receives hot water from a heated water tank located below it by a conveying device which is arranged there and rotates along with it. About the coffee maker.

In the case of this type of coffee maker, in which the conveying device and the centrifugal filter both rotate without relative rotation, there is a problem that the conveying device sprays hot water unevenly onto the coffee powder ring that is formed inside the coffee filter. This creates an imbalance and consumes the coffee grounds unevenly. Furthermore, in order to prevent unbalances, the centering device allows the centrifugal filter to be well centered with respect to the motor shaft together with the conveying device without requiring very precise and therefore expensive production. There is a problem.

The object of the invention is to create a coffee maker of the type mentioned at the outset in such a way that imbalances are prevented, hot water is supplied evenly distributed over the coffee grounds, and the coffee grounds are consumed in a good manner.

This object, according to the invention, is such that the conveying device has a plurality of conveying channels for hot water distributed over the circumference, which conveying channels are preferably arranged inside the conveying device distributed over the circumference. This is achieved by being formed between ribs. Therefore, the hot water that enters these channels is sprayed onto the coffee grounds.
It is supplied to a predetermined area of the outlet opening, thereby spraying the coffee grounds evenly and circumferentially. The ribs then preferably extend over the entire height of the conveying device as far as the outlet opening.

Preferably, a portion of the rib is used for centering the conveying device on a transmission body mounted on the motor shaft. This provides great flexibility of the centering device, allowing for large manufacturing tolerances and therefore low manufacturing costs. As the conveying device, a hollow cone is used which widens upwards and on the inside of which ribs extend preferably vertically. The ribs are then preferably formed as projections on the inner wall of the hollow cone. A gently inclined truncated cone is used as the transmission body, with a centering rib adjoining the truncated cone at its inner edge. This inner edge is inclined at the same angle as the outer peripheral surface of the transmission body with respect to the central axis.

The conveying capacity of the conveying device, the actual outer filter and the filter shape of the centrifugal filter, when using fine or medium-grained coffee grounds,
They are mutually determined so that a hot water pool is formed in the centrifugal filter that extends inward to the front of the coffee powder layer. For example, a filter cavity is used as the actual filter.

In this way, when hot water flows through the centrifugal filter over a long period of time, there is a uniformly distributed hot water ring in the centrifugal filter, in which the coffee grounds are accommodated, and the filter Even if non-uniform distribution occurs within the range, no imbalance will occur.

Preferably it is provided that the centrifugal filter is completely filled with hot water. The conveying device therefore has a much larger conveying capacity than the centrifugal filters with which coffee powder is normally filled, so that the overall feed rate depends on the resistance of the actual filter and the coffee powder layer around the circumference of the centrifugal filter. It depends only on In this way it is ensured that coffee grounds are always present in the hot water reservoir.

The conveying device is preferably closed at its outlet end by one or more outlet openings, the minimum internal width of which is no greater than approximately 1/100 to 50/100 mm. This ensures that even if the motor is stopped prematurely, the coffee powder particles flow back into the conveying device through the outlet opening and are pushed back into the water tank.
This prevents the aquarium from getting dirty. The coffee grounds block the opening and prevent the coffee present in the coffee filter from flowing back into the conveying device and into the water tank.

Preferably this minimum inner width is approximately 1/100 and 30/10
0 mm and in particular between 1/100 and 5/100 mm, which in particular ensures a good prevention of backflow of coffee grounds. If an annular gap extending around the axis of rotation of the conveying device is formed between the conveying device in the form of a hollow cone as an outlet opening and a lid fitted into the upper end of the hollow cone, the part In order to obtain a sufficient annular gap when the parts are completely abutted against each other, the surfaces of the parts do not need to be flat. Preferably, the total cross-sectional area of the outlet opening or the total cross-sectional area of all outlet openings is such that a pool of hot water is created in the conveying device. This reservoir produces a uniform distribution over all openings or over the entire length of the annular gap, so that the coffee grounds present in the actual centrifugal filter surrounding the conveying device can be evenly fed, which is particularly important during the start-up phase. It is important in

Embodiments of the present invention shown in the drawings will be described in detail below.

The electric coffee maker shown in the drawings has a vase-shaped base case 2 which has a support base 4 formed laterally for receiving two coffee cups 6 side by side. On the pedestal case 2, there is placed an aquarium 8, which is generally formed in the shape of a bowl as a whole, and has a bottom 10 that descends toward the center. 12 are arranged. The bottom 10 transitions in the central region into an annular projection 14 projecting upwards into the aquarium 8, which is connected to the vertical axis 1 of the electric motor 18.
6 passes through this tubular projection 14, and an electric motor 18 is supported by a holder 20 formed on the underside of the bottom 10 of the aquarium 8.

The centrifugal filter 22 has a hollow cone 24 that projects downward into the water tank 8 and widens upward, and this hollow cone 24 is used as a conveying device for hot water. A transmission body 25 is mounted on the motor shaft 16 in a relatively non-rotatable manner, and the transmission body 25 covers the tubular protrusion 14 of the water tank 8 with its outer peripheral surface that is gently inclined and widens downward, and reaches the bottom area of the water tank 8. It protrudes downward. The hollow cone 24 has three centering ribs 27 projecting from its inside and extending over its entire height, the inner edges of these centering ribs 27 being aligned with the outer peripheral surface of the transmission body 25 with respect to the axis of rotation. They are inclined at the same angle and are pressed onto the outer peripheral surface of the transmission body 25 from above. Between the two centering ribs 27 there is in each case another rib 28 which does not project as far as the outer peripheral surface of the transmission body 25 . These auxiliary ribs 28, which are not used for centering, are used to form a number of vertical channels in the hollow cone 24, in order to distribute hot water as evenly as possible over the circumference. . The hollow cone 24 is closed on the upper side by a lid 29 , with an annular gap 54 opening between the hollow cone 24 and the lid 29 for supplying hot water to the coffee grounds 52 . Lid 29 has centering rib 2
7 and an auxiliary rib 28, and its inner side has meshing teeth that removably mesh with meshing teeth 26 at the upper end of the transmission body 25.

A collection chamber 3 in the shape of an annular gutter is located on the upper edge of the water tank 8.
0, this collecting chamber 30 has a bottom 32 that descends toward the coffee cup 6 mounting table 4, and an outlet channel 34 that projects approximately radially outward and is branched into two outlets 36. ing. In addition, 1 is shown in the drawing.
Only one outlet 36 is shown. A lid 38 is placed on top of the gathering chamber 30, and this lid 38 has a cylindrical annular wall 40 projecting downward.
protrudes downward into the annular gathering chamber 30, receives the coffee splashing from the centrifugal filter, and guides it downward into the annular chamber.

Next, we will explain how this coffee maker works. The lid 38 is removed and the centrifugal filter 22 is placed on the shaft 1.
6, fresh water is poured into the water tank 8 from above. Then, after removing the lid 50 of the centrifugal filter 22,
2 is filled into this centrifugal filter 22. Finally, the centrifugal filter 22 is inserted onto the transmission body 25 fixed to the shaft 16 and its meshing teeth 26,
A lid 38 is put on and two coffee cups are placed on the platform 4 below the outlet 36. By operating the start switch 60, the heater 12
is injected. As soon as a temperature sensor (not shown) placed in the water tank 8 reaches the boiling water temperature, the signal lamp 62 is turned on. The coffee maker is then ready and when the user wishes to drink coffee, the user can actuate the push button switch 64 to start the motor 18. As a result, the centrifugal filter 22 is rotated and the coffee grounds 52 are first distributed in an annular manner as shown. As soon as a sufficient rotational speed is reached, the hollow cone 24 begins to convey hot water and sprays the coffee grounds 52 through the annular gap 54 at its upper end. The coffee made is passed through a centrifugal filter 22
The coffee flows out through the annular gap 56, is received by the annular wall or capture wall 40 of the lid 38, and is directed downwards into the collection chamber 30, from where it is fed through a distributor and an outlet 36. It flows into the coffee cup 6 through the flow path 34. The rotated coffee produces an externally visible coffee structure on the transparent annular wall or capture wall 40, which changes significantly when the coffee is rotated only slightly or not at all. The user can stop the motor by turning off pushbutton switch 64. The last coffee to be rotated requires only enough time for the coffee to flow downwards along the annular wall 40 through the collecting chamber 30, the channel 34, the distributor and the outlet 36 into the coffee cup 6. This rotation process takes about 35 to 40 seconds, during which time the user presses the push button switch 64.

The horizontal annular gap 54 between the lower side of the lid 29 and the upper edge of the hollow cone 24 used as a hot water conveying device has a gap width or inner width of 3/100 mm.
This annular cavity 54 is spaced from the bottom of the space containing the coffee grounds 52 by a distance of approximately 1/3 of the height of this space.

The annular gap 54 at the outlet end of the conveying device, the entire conveying device, the outer annular gap 56 in the coffee filter 22, the shape of the filter, and the resistance of the coffee ground layer in the filter are such that the resistance of fine or medium-grained coffee When powder is used, the coffee powder layer 52 is designed to form a pool of hot water. During most of the boiling process, a hot water ring is present inside the coffee grounds ring 52, ie radially in front of the coffee grounds.
This results in a high extraction rate in the coffee, ie a good consumption of the coffee grounds. The grain size of coffee powder is determined according to West German Patent Application No. 2755014, column 1, lines 47 to 47.
It is written on line 55.

Preferably, the above-mentioned determination of the flow rate for filling the filter with hot water is such that the filter is filled with hot water for the majority of the filtering action and that a pool of hot water occurs up to the conveying device, especially on its suction side. It will be done. In this case, the speed of conveyance is determined by the size of the filter gap 56 and the abrasion resistance of the coffee ground layer. The annular gap 56 becomes the actual filter.

[Brief explanation of drawings]

Figure 1 is a sectional view of a coffee maker with a centrifugal filter according to the present invention (-
Figure 2 is a cross-sectional view along the line), and Figure 2 is a -
It is a sectional view along a line. 2...Equipment case, 6...Coffee cup, 1
8...Electric motor, 22...Centrifugal filter, 24
... Conveyance device, 25 ... Transmission body, 27 ... Centering rib, 28 ... Auxiliary rib, 52 ... Coffee powder,
54... Outlet opening, 56... Annular void.

Claims (1)

[Scope of Claims] 1. In an electric coffee maker having a centrifugal filter that is detachably connected to a motor shaft and receives hot water by means of a conveying device disposed thereon and rotating along with the centrifugal filter, the conveying device 24 An electric coffee maker with a centrifugal filter characterized in that it has a plurality of conveying channels for hot water distributed over its circumference. 2. The coffee maker according to claim 1, wherein the conveying device 24 has ribs 27, 28 on at least its upper portion to form a conveying flow path therebetween. 3. The coffee maker according to claim 2, characterized in that the ribs 27, 28 extend over the entire height of the conveying device 24. 4. The coffee maker according to claim 2 or 3, characterized in that the ribs 27, 28 run vertically. 5. The coffee maker according to claim 2 or 3, wherein the ribs 27, 28 run in a spiral shape. 6 Some of the ribs 27 and 28 are attached to the centrifugal filter 22
3. The coffee maker according to claim 1 or 2, wherein the coffee maker is used as a centering rib 27 for centering a transmission body 25 attached to a motor shaft 16. 7 Hollow cone body 2 as a conveying device that expands upward and has ribs 27 and 28 extending inside it.
7. The coffee maker according to any one of claims 1 to 6, characterized in that a coffee maker having a coffee maker of 4 is used. 8. The coffee maker according to claim 6 or 7, wherein the transmission body 25 has a gently sloping truncated conical outer peripheral surface that is in contact with the inner edge of the centering rib 27. . 9. Coffee maker according to any one of claims 6 to 8, characterized in that each second rib is a centering rib 27. 10 When the conveying capacity of the conveying device 24 is to use coffee powder with fine or medium grains, the original filter on the outside of the centrifugal filter 22 should be 10. The coffee maker according to claim 1, wherein the coffee maker is determined by the annular gap 56 and the shape of the filter. 11. The coffee maker according to claim 10, characterized in that the centrifugal filter 22 is completely filled with hot water. 12. Claim 1 characterized in that the outlet end of the conveying device 24 is closed to one or more outlet openings 54, the minimum internal width of which is at no point greater than about 1/100 to 50/100 mm. The coffee maker according to any one of Items 1 to 11. 13 The minimum inner width of the exit opening 54 is approximately 1/100 and 3
13. Coffee maker according to claim 12, characterized in that the diameter is between 0/100 mm and in particular between 1/100 and 5/100 mm. 14. Coffee maker according to any one of claims 1 to 6, characterized in that an annular gap 54 extending around the rotation axis of the centrifugal filter is used as the outlet opening. 15. The total cross-sectional area of the outlet opening 54 or the total cross-sectional area of all outlet openings is determined in such a way that it acts to block the hot water in the conveying device 24. 7th
The coffee maker described in any of the paragraphs.