CA1071421A

CA1071421A - Filter device for producing aromatic extracts from coffee or tea

Info

Publication number: CA1071421A
Application number: CA304,812A
Authority: CA
Inventors: Reinhard Haeuslein
Original assignee: Melitta Werke Bentz and Sohn KG
Current assignee: Melitta Werke Bentz and Sohn KG
Priority date: 1977-06-08
Filing date: 1978-06-05
Publication date: 1980-02-12
Also published as: NL181775C; AU3674078A; SE437756B; FI67017B; JPS544664A; NO147231B; BE867897A; LU79782A1; DE2725854C2; DK147193C; CH630794A5; DK232778A; SE7805605L; ZA783283B; DK147193B; NO781993L; NO147231C; FR2393554A1; AT368857B; ES470573A1

Abstract

ABSTRACT
Filter vessel for making coffee or tea, having the outlet from the filter vessel in the form of a siphon so that dripping upon completion of the filtering operation is reduced or avoided.

Description

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The present invention relates to a ilter device or producing aromatic extracts from cofee or tea.
In the case o known ilter devices of the type consi~ting of a filter vessel and a filter cone, the outlet rom the ~ilter vessel is in the form of one or more passages at the lowest point in the filter vessel, in order to ensure complete emptying.
The disadvantage of this arrangement is that the filtering operation is complete, and after the filter device has been removed from the pot holding the filtrate~ residual filtrate may drip outside the said pot and dirty the area around it. This is particularly inconvenient in the case of coffee-making machines, in which the filter device is suspended and remains in the machine after the iltering operation has been completed, since in this case the drops of residual filtrate drip onto the surface of the hot plate of the coffee-making machine and are burned thereon.
It is therefore the purpose of the present invention to provide a filter device whereby such dripping upon completion of the filtering operation may be eliminated or considerably reduced.
According to the invention, this purpose is achi~ved by providing an outlet from the filtar vessel in the orm of a siphon.
This ensures an ùninterxupted discharge of filtrate during the filtering operation, but cuts off the flow of filtrate in the final phase thereof, so that any residual filtrake that may collect cannot reach the outside throug~ the siphon, and after-dripping is reduced or avoided.

Examples of embodiment of the invention are illustrated in the accompanying drawings and are explained hexeinafter in greater detail. In the said drawings:
~ ig. 1 shows a cross section through a filter device according to the invention;
Fig. 2 shows a cross section through a filter device in another example of embodiment of the invention, Fig. 3 shows a cross section through still another filter device according to the invention;
Fig. 4 is a section along the line IV-IV in Fig. 3;
Fig. 5 shows a cross section through a filter device in another example of embodiment of the invention;
Fig. 6 is a view in the direction of arrow VI in Fig.
5;
Fig. 7 is a section along the line VII-VII in ~ig. 5.
The filter device shown in Fig. 1 consists essentially of a filter vessel 1 containing a conventional filter cone 2 e.g.
of paper. Filter vessel 1 has a supporting edge 3 by means of which th~ said vessel may be placed upon a pot or other receptacle.
According to the present invention, outlet 4 from fllter vessel 1 is in the form of a siphon and consists, in the example of embodiment according to Fig. 1, of a length of bent pipe 5, the suction aperture of which is located in ~he interior of filter vessel 1 immediately above the lowest point therein, while outlet aperture 7 is located externally of filter vessel 1 and at a lower level than suction aperture 6. Thus the filtrates can flow from vessel 1 on the siphon principle i, during the brewing process, enough water is used to reach the upper deflecting edge 8 of bent pipe 5. This level of water is shown

- 2 --by a line 9 in Fig. 1. As long as there is enough liquid in the filter device to bring the water level above line 9, the filtrate will pass into the pot through pipe 5. As already indicated, this is based upon the principle of the siphon, and the discharge of the filtrate is interrupted only when air reaches suction aperture 6 in the said pipe, which occurs when the liquid in filter vessel 1 has been almost completely drawn off. This makes it impossible for any filtrate remaining in the cone after the filtering operation to drip from filter cone 2 to the outside.
- It may thus be possible to effectively and reliably prevent after-dripping or at least to considerably reduce such after-dripping.
The leg of pipe 5 projecting into filter vessel 1 is in alignment with a rib 10 provided in the interior thereof~
upon which filter cone 2 rests. The position of the said cone in the interior of the filter vessel is therefoxe not affected by the leg of pipe 5 projecting thereinto.
In Fig. 4, and in the subsequent figures, the filter cone is not shown. In the example of embodiment according to Flg. 2, outlet 4 is also in ~he form of a length of pipe 5, but the latter is bent in such a manner that outlet aperture 7 is located approximately centrally of the filter vessel. Apart from this, the design and method of operation of outlet 4, in the example of embodiment according to Fig. 2, are as in the example of embodiment according to Fig. 1.
Figs. 3 and 4 show an example of embodiment of the invention in which an adapter 12 in the bottom of the filter vessel is inserted sealingly into an aperture in the said vesselO

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Mounted in the said adapter is an approximately U-shaped piece of tube 13, the suction aperture 6 of which is again located directly above the lowest point in filter vessel 1, whereas outlet aperture 7 is located outside. Tube 13 is arranged in a recess 14 in the filter vessel and therefore does not affect the seating of the filter cone. Again in this example, the filter vessel is completely emptied by tube 13 acting as a siphon, thus reducing or avoiding any dripping after the filtering operation has been completed. One particular advantage of this design is that adapter 12 and tube 13 may be removed from the filter vessel when required. This not only facilitates cleaning, but also makes it possible to use the filter vessel as a normal filter vessel if any defect arises in adapter 12 or tube 13.
Figs. 5 to 7 show a particularly advantageous example of embodiment of the invention. In this case, filter vessel 1 is a single piece of plastic, in which outlet 4 is in the form of a system of ducts consisting of guide ribs 15 to 17 project-ing into the interior of filter vessel 1. These guide ribs form a duct 18 running upwardly from suction aperture 6a, again located above the lowest point in the filter vessel, and another dùct 19 running downwardly to outlet aperture 7a~ Guide ribs 15 to 17, which run into a rounded area 20 at the centre of filter vessel 1, as shown clearly in Fig. 5, are slightly higher than ribs 10, i.e. they project slightly farther into the interior of the filter vessel than ribs 10 wh:ich support the filter cone.
This ensures that the filter cone at all times bears snugly against guide ribs 15 to 17, especially at the beginning of the filtering operation, i.e. when the water is poured in since, at 10~LZl that time, the cone is softer than it is in the dry condition, and thus almost forms a seal with the said guida ribs under the pr~ssure applied by the water and the ground coffee. As a result of this, ducts 18 and 19, which are defined by guide ribs 15 to 17~ form, in conjunction with the filter cone bearing against theml a pipe system which again acts as a siphon.
The embodiment illustrated in Fig~ 5 to 7 has considerable production advantages since, as already indicated, it may be made in one piece out of a synthetic material. This design also has advantages from the practical point of view, in that it is very easily cleaned at the end of the filtering operation.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a filtering device for producing aromatic extracts from coffee or tea, including a filter vessel having an extract outlet at a range to receive a filter bag, the improvement wherein said vessel is provided with an outlet opening in the vicinity of its bottom, and said extract outlet comprises a plurality of guide ribs projecting from the interior wall of the said vessel and defining a first channel section extending upwardly from a location spaced from said outlet opening and immediately adjacent the lowest point of the interior of said vessel, and a second channel section communicating at its lower end with said outlet opening, said first and second channel sections communicating with one another at their upper ends to form a conduit which is laterally opened toward the interior of said vessel, said guide ribs being arranged to permit a filter bag inserted in said vessel to rest tightly thereagainst to close the laterally opening side of said conduit and to enable said conduit to operate as a siphon, when the filter bag is filled with water, with the lower end of said first channel section defining a suction opening.

2. A filtering device according to claim 1, in which the guide ribs run into a concavely rounded-off area at the center of the filter vessel.

3. A vessel according to claim 1 or claim 2, in which the guide ribs are slightly higher than a set of ribs that are provided for supporting the filter cone in the interior of the filter vessel.

4. A filtering device as claimed in claim 1 wherein the guide ribs are integral with said vessel.

5. A filtering device as claimed in claim 1 wherein said extract outlet further comprises a member projecting upwardly from the interior of said vessel and located in the region of the bottom thereof between the lowest point of the interior of said vessel and said outlet opening for preventing direct flow of liquid therebetween.