DE102007060813A1 - Automatic coffee machine, for espresso coffee, has a cylinder with a sliding piston with a perforated curved surface and a closing piston - Google Patents

Abstract

The automatic coffee machine has a cylinder (1) for the coffee and hot water. The cylinder base has a central passage opening (2), an open end (5), a closing piston (9) and a sliding piston (4) to compress the coffee grounds. The coffee-making chamber (10) is formed by the closing piston and a cylinder inner wall. The sliding piston has passage openings (11) for hot water to pass through and its upper surface has a one-dimensional curvature.

Description

The The invention relates to a brewing cylinder as part of a Brewing group of a coffee machine according to the generic term of claim 1

The EP 0 561 741 A1 discloses a cup-shaped brewing cylinder as part of a brewing group of a coffee machine, which has a cylindrical wall and at its lower end a bottom. At the upper open end of the brewing cylinder, a closing piston for closing the cylinder is attached. By the closure piston and a movable brewing a brewing chamber is limited inside the brewing cylinder.

The necessary for brewing a coffee beverage Ground coffee is added when the stopper is removed and comes in the brewing cylinder to lie. The preparation of a coffee drink finally done by the brewing cylinder before moved against the shutter piston, and thereby the shutter piston is moved into the brewing cylinder, and so a brewing chamber seals upwards.

From a hot water heater flows heated water, hereinafter referred to as brewing water, via a Supply line and a correspondingly switched valve member in a radially leading into a lower extension of the brewing cylinder Management. From this line, the brewing water passes finally via a channel on the back of the movable brewing piston, then through passages in the movable brewing piston through into the brewing chamber to pour and brew the compacted ground coffee there.

The Compaction of the ground coffee is in such coffee machines or Coffee machines to achieve a good, quality provided with the coffee beverage co-determining crema. The condensed Ground coffee forms a throttle section for the brewing water whereby a brewing pressure is generated in the brewing chamber that is the essential oils from the ground coffee pressing, which form the crema.

From the EP 0 756 842 B1 It is also known to improve the quality of the brewed coffee beverage in that only a certain pressure is built up in the brewing chamber before the finished coffee beverage can flow out of the brewing chamber. In order to achieve this brewing pressure, a crema valve closing the brewing chamber downstream is provided which only opens the brewing chamber to the outflow of the finished coffee beverage when a desired opening pressure is reached.

The above brewing cylinder known coffee machines However, they can have the disadvantage of being high, high the highly compressed ground coffee or counter pressure generated by the crema valve not all zones of the ground coffee are sufficiently moistened and thus in these areas the essential oils only insufficiently squeezed.

at Coffee machines with brewing cylinder with crema valve can be added as disadvantageous that upon reaching the target opening pressure and corresponding opening of the crema valve a sudden channel-like Breakthrough of the brewing water on the shortest route through the brewing chamber in the direction of the coffee spout, whereby zones of the ground coffee are only insufficiently leached.

But even at relatively low pressures and in the absence of a crema valve may be in the compacted ground coffee unwanted breakthrough channels form the brewing water.

Of the present invention is based on the object, a brewing cylinder as part of a brewing group of a coffee machine to provide a uniform in avoiding the above drawbacks Moistening, squeezing and leaching of all zones of ground coffee reliably in the brewing chamber, whereby a best possible use of the ground coffee and an optimized Crema should be achieved.

These Task is a brewing cylinder as part of a Brewing group of a coffee machine with those in the characterizing Part of claim 1 specified features solved.

advantageous Training and further education, which individually or in combination with each other can be used are the subject of the dependent claims.

The inventive solution is based on that in a constructive way the way of brewing water through the compacted ground coffee is prolonged. An entrance described brewing cylinder as part of a brewing group a coffee machine is inventively characterized further developed that the surface of the brewing piston is formed as a curved circular surface.

When brewing water enters a brewing chamber through passage openings in the edge region of a curved brewing piston, a substantially longer and, in particular, branched flow path is forced through the compacted ground coffee. Surprisingly, it was found that it swirls in the area of the brewing cylinder inner wall Brühwassers comes because individual flows collide with each other or reflections form on the chamber inner wall.

Especially if the passage openings in the edge region of the brewing piston approximate due to the curvature of the circular area orthogonal with respect to the shortest path in the direction of Coffee outlet are arranged, all zones of the ground coffee evenly moistened. This will be the best possible Use of the ground coffee and an optimized crema achieved.

The Passage openings are over the entire surface the brewing flask, preferably evenly, distributed.

In a preferred embodiment of the invention Brühkolbens are passage openings both in Edge area as well as in a central annular area educated.

In a further preferred embodiment of the invention Brewing piston differ the passage openings in size from each other, namely, that in the edge area are larger or one have larger diameter than those in the central annular area.

In a still further preferred embodiment of the invention Brühkolbens are the passages only in the edge region, particularly preferably in an annular Area of the edge area arranged.

each rotationally symmetric convex, spherical or aspherical Piston surface with passages, in particular in the edge area, is suitable the flow path of the brewing water to extend through the compressed ground coffee. The circular area is curvature continuous or not curvature continuous, one or formed curved two-dimensionally.

To An advantageous embodiment of the invention is the surface of the brewing piston as a one-dimensional curvature continuous curved circular area formed.

To a particularly advantageous embodiment of the invention is the Radius of curvature of the one-dimensionally curved Circle area equal to the radius of the circle on its circular path the rotation-mounted brewing cylinder in the direction of a fixed Locking piston is movable. This will ensure that an extended brewing piston with a one-dimensional Curved continuous curved surface be guided past a fixed scraper at a constant distance can.

In this configuration, the brewing cylinder after a coffee brewing on a circular path again transferred to the loading position while the leached coffee cake are stripped off. The mobile one Brühkolben is up to an open end portion of the brewing cylinder extended. The stripping is done by the one-dimensional curvature continuous curved surface of the brewing flask as well as an upper open end of the brewing cylinder at one fixed scrapers are passed.

The above and to be explained below Features are not only in the specified combination, but also usable in other combinations or in isolation, without departing from the scope of the present invention. So are for example, radius of curvature and arrangement and size the passage openings the respective brewing cylinder adapt.

in the The following is an exemplary embodiment with reference to the drawings the invention described in more detail. In the drawings show schematic and simplified:

1 a longitudinal section through a brewing group in the loading phase,

2 a longitudinal section through a brewing group in the brewing phase and

3 a longitudinal section through a brewing group in the ejection phase.

1 shows a longitudinal section through a brewing group of a coffee machine in the loading phase. During the loading phase or also resting phase, the coffee grounds necessary for brewing a coffee beverage from above into the brewing cylinder can be filled.

In 1 is with 1 a brewing cylinder designates a central breakthrough 2 at the cylinder bottom for the passage of a piston rod 3 a slidably mounted brewing piston 4 , an open end section 5 and a brewing water inlet 6 having. During the loading or resting phase is the brewing flask 4 withdrawn. The cylinder 1 is in the pivot 7 rotationsgelagert and therefore relatively on a circular path 8th in the direction of the fixed closure piston 9 by a drive and guides not shown rotatably movable.

In addition to the rotational mobility is the brewing cylinder 1 previously translational by a drive, not shown, and guides against a fixed closure piston 9 movable, causing the shutter piston 9 in the brewing cylinder 1 retractable and so a brewing chamber 10 is sealable to the top.

2 shows a longitudinal section through a brewing group of a coffee machine in the brewing phase. During the brewing phase is in the brewing chamber 10 compacted ground coffee 12 flows through brewing water.

The cylindrical brewing chamber 10 is during the coffee brewing of a fixed closure piston 9 , a displaceably mounted brewing flask 4 and a portion of the brewing cylinder inner wall limited. The brewing flask 4 has passage openings in the edge area 11 for the passage of brewing water. The surface of the brewing piston is formed as a one-dimensional curvature curved circular surface. Due to the curvature are the openings 11 aligned in the direction of the brewing cylinder inner wall. This is what happens in the compacted ground coffee 12 in the area of the inner wall to turbulence 13 the brewing water, since individual flows collide with each other or because reflections form on the cylinder inner wall. This has a uniform moistening and leaching of all zones of compacted ground coffee 12 in the brewing chamber 10 result in the best possible use of the ground coffee and an optimized crema can be achieved. About one in the closure piston 8th integrated coffee outlet 14 the finished coffee beverage flows out of the brewing chamber 10 ,

3 shows a longitudinal section through a brewing group of a coffee machine in the ejection phase. During the ejection phase, the leached coffee cake from the brewing flask 4 stripped off, and the brewing cylinder 1 again transferred to the loading position.

In 3 is with 15 a fixed scraper refers to the leached coffee cake from the surface of the brewing cylinder 4 scrapes. The coffee cake then slips over the sliding surface 16 in a drip tray (not in the figure). For this purpose, the brewing cylinder pivots after a coffee brewing 1 on the circular path 8th back to a vertical loading or rest position. The movable brewing flask 4 is in it up to the open end section 5 of the brewing cylinder 1 extended. The fixed scraper 15 pushes the leached coffee cake during the rotational movement of the brewing cylinder 1 from the surface of the brewing flask.

The the surface of the brewing flask 4 is formed as a one-dimensional curvature continuous curved circular area. The radius of curvature of the circular area is equal to the radius of the circle on the circular path of the rotationally mounted brewing cylinder 1 in the direction of the fixed closure piston 9 is movable. This ensures that the extended brewing piston with a to the fixed scraper 15 constant distance past this is passed.

1

brewing cylinder

2

breakthrough

3

piston rod

4

brewing plunger

5

end

6

Brühwassereinlass

7

pivot point

8th

orbit

9

closure piston

10

brewing

11

Through openings

12

densified ground coffee

13

turbulence

14

coffee outlet

15

scraper

16

sliding surface

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 0561741 A1 [0002]
• EP 0756842 B1 [0006]

Claims (7)

Brewing cylinder ( 1 ) as part of a brewing group of a coffee machine, with a central breakthrough ( 2 ) at the cylinder bottom, an open end portion ( 5 ), a closure piston ( 9 ), a displaceably mounted brewing piston ( 4 ) and a cylindrical, by the brewing piston ( 4 ), the closing piston ( 9 ) and a portion of the brewing cylinder inner wall limited brewing chamber ( 10 ), characterized in that the brewing piston ( 4 ) Passages ( 11 ) for the passage of hot water and the surface of the brewing piston ( 4 ) is formed as a curved circular surface. Brewing cylinder ( 1 ) according to claim 1, characterized in that the passage openings ( 11 ) over the entire surface of the brewing piston ( 4 ) are evenly distributed. Brewing cylinder ( 1 ) according to claim 1, characterized in that passage openings ( 11 ) both in an annular edge region and in a central annular region of the brewing piston ( 4 ) are formed. Brewing cylinder ( 1 ) according to claim 1, characterized in that passage openings ( 11 ) only in an annular region of the edge region of the brewing piston ( 4 ) are formed. Brewing cylinder ( 1 ) according to one of claims 1 to 4, characterized in that the surface of the brewing piston ( 4 ) is formed as a one-dimensionally curved circular area. Brewing cylinder ( 1 ) according to claim 5, characterized in that the surface is formed as a one-dimensional curvature curved circular surface. Coffee machine with a brewing cylinder ( 1 ) as a constituent of a brewing group according to one of claims 1 to 6.