US 6,189,438 B1Granted

Filtering device, filter element and method of manufacturing the filter element used for the preparation of brewed beverages

AssigneeBraun GmbH

InventorsUwe Bielfeldt, Christof Kleemann, Reinhard Stücher, Bernd Trebitz, Horst Emmerich, Dieter Friedrich, Christian Ziesch, Frank Gliemroth

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Abstract

The invention is directed to a filtering device, a filter element therefor and a method of manufacturing the filter element (28) from filter paper. The filter element (28) has a receiving cavity (76) to be filled with extractable materials such as coffee grounds or tea leaves. Following contact with hot water, the extractable materials deliver extractive substances to the water, resulting in a brewed beverage that is drained from the filter element (28). During this process, the filter element (28) is held by the filter support (1) by way of a supporting member which includes a rim (39) formed on the filter element (28) and having a bearing surface (40), and a supporting surface (24) formed on the filter support (1). The rim (39) of the filter element (28) is reinforced mechanically by providing the filter paper with exposed pleats (42, 51, 52) which cooperate with corresponding elevations (115) and recesses (79) formed on the supporting surface (24) of the filter support (1). Such a filtering device of the present invention enables its manipulation and manufacture to be significantly facilitated. At the same time, improved brewing results are obtained. The operations of inserting such a filter element (28) in a filter housing (16) and filling it with coffee grounds, for example, are also improved. It is possible to manufacture a plurality of filter elements (28) in a single operation. At the same time, the filter elements are stackable in a minimum of space. The filter element is held in the filtering device without any additional fastening.

A filtering device for making brewed beverages, comprising:

a filter support defining a filter receiving cavity having an upper opening and including a supporting surface formed thereon and circumscribing the filter receiving cavity near the upper opening thereof;
and
a filter element fabricated from filter paper, the filter element having a materials receiving cavity to be filled with extractable materials which, following contact with hot water, deliver extractive substances to the water, resulting in a brewed beverage that is drained from the filter element, said filter element including a rim formed on the filter element and having a bearing surface, said rim extending in a direction away from the receiving cavity of the filter element outwardly, said bearing surface of the rim bearing against the supporting surface formed on the filter support upon insertion of the filter element into the filter support, and said rim of the filter element being reinforced mechanically by pleating the filter paper with outwardly extending pleats that also extend into the rim, the pleats being configured as exposed pleats so that paper surfaces do not overlap, the pleats in the area bounding the receiving cavity being equally spaced, the pleats in the rim and in the receiving cavity being of a zigzag or undulating structure in cross section, causing a crest pleat to be followed by a trough pleat in alternation in the circumferential direction of the filter element, in a radial direction of the filter element at a junction of a transition area with the rim, a crest pleat changing into a trough pleat and vice versa, the supporting surface of the filter support also being of a zigzag or undulating structure along its circumference as a result of which an elevation is followed by a recess in alternation in the circumferential direction of the filter support for cooperation with the crest pleats and the trough pleats of the rim of the filter element.

Abstract

Claims25