The present invention relates to a filter unit for making an extraction drink, such as tea or the like, from e.g. tea leaves or the like, said filter unit comprising two components, a tubular filter component which delimits an interior space for receiving a portion of tea leaves for producing the extraction drink, and a handle or grip component, said tubular filter component having an exterior wall part which is perforated to allow the diffusion of water from the interior space within the filter through the perforated exterior part in or out, and said tubular filter component delimiting opposite ends, a first, closed end and another, open end by means of which the handle is connected to the filter component, the handle component having a gripping flange extending outwards from the exterior wall of the filter component.

There are known in the art several filter units or filter constructions for making of tea of both the disposable and the reusable type, the filter unit being filled entirely or preferably partially with tea leaves, after which the filter unit is mounted hanging in or extending down into the interior of a teapot from the opening thereof. Making of the extraction drink or tea follows subsequently by pouring boiling water over the filter unit, after which the filter unit containing tea leaves is allowed to remain in the interior of the teapot until the tea has infused a certain amount of time determined individually by the user in order to provide a more or less strong extraction drink or tea. Several filter constructions adapted to be used in connection with teapots are known from the patent literature. Thus, reference is made to DK-Patent No. 54,652, DK-Patent No. 99,827, German Publication No. 43 01 157, German Publication No. 1962 378, and GB-Patent No. 437,694. These known filter constructions, which are all of the reusable type, i.e. they may be used after the filter unit after use is emptied of used tea leaves and subsequently washed, have in common the fact that the filter unit may only be used in connection with teapots of a relatively large size and in particular cannot be used in connection with, for example, thermos bottles. It has thus been necessary for tea drinkers who wanted to keep the tea warm in the thermos bottle first to brew the tea in a teapot, and afterwards to pour the tea from the teapot into the thermos

bottle.

It has to be mentioned that there are known several disposable filter constructions, especially tea filter bags made of paper which are either used alone or in connection with a holder, but neither they can be used in connection with a thermos bottle.

Especially from GB-Patent No. 626,914 there is known a filter unit of the above mentioned kind. This known filter unit is formed in such a way that the handle or grip component constitutes a lid component of a teapot in connection with which the filter unit is to be used. The known filter unit is thus used in a particular way, as the filter component, which comprises a perforated cylinder part with a closed bottom part, is filled with tea leaves after which boiling water is poured down into the interior of the teapot. The filter component is mounted afterwards in an interior collar in the teapot lid component which constitutes the handle or the grip component, after which the lid component with the assembled filter component is mounted on the teapot, so that the filter component is lowered into the boiling water entirely or partially.

Subsequently, the filter component may be removed from the lid component after the lid component is removed from the teapot, but this operation must necessarily imply the use of potholders or any other thermally insulating intermediate layer to prevent the person who removes the filter unit from the lid component from burning himself or herself when touching the filter component. Thus, this known construction is not adequate in use and consequently has not achieved widespread commercial popularity, neither in connection with teapots, nor with other recipients, including insulated bottles, such as thermos bottles.

One object of the present invention is to provide a filter unit for the production of an extraction drink, such as tea or the like, which filter unit makes it possible to produce the extraction drink or the tea directly in a thermos bottle, i.e. to provide a filter unit which may be used in connection with a thermos bottle, allows and, moreover, facilitates the introduction of tea leaves and the pouring of boiling water inside the filter unit while the filter unit is introduced in the thermos bottle, and makes it possible to readily remove the filter unit

from the thermos bottle after the tea is brewed therein.

The above mentioned object together with several other objects, advantages, and advantageous features which will be evident from the subsequent detailed description of the advantageous embodiments of the filter unit according to the invention are achieved in accordance with the teachings of the invention by means of a filter unit of the above mentioned type, said filter unit being characterized in that the handle or grip component has an inclined interior surface forming a funnel- shaped introduction opening to the interior space of the filter and is adapted to keep the filter unit in an opening in a thermos bottle or a similar recipient so that the filter unit is mounted with the filter component extending downwards into the interior of the thermos bottle, that the tubular filter component defines an overall exterior length and a largest exterior diameter, the ratio between the overall exterior length and the largest exterior diameter of the tubular filter component being larger than 1.5, such as 1.5-5, e.g. 2-3, 3-4 or 4-5, preferably 3-5, e.g. 4-4.5, and that the largest exterior diameter of the tubular filter component is less than 50 mm, such as 20-50 mm, e.g. 20-30 mm, 30-40 mm or 40-50 mm, preferably 30-50 mm, e.g. 30-35 mm.

The grip or handle component serves two purposes: firstly, to allow the filter unit to be manoeuvred, and, secondly, to keep the filter unit in use in the intended position, with the filter component extending downwards into the interior of the thermos bottle, the grip or handle component thus serving to retain the filter unit either in tension or as a flange in relation to the thermos bottle at the upper opening of the thermos bottle.

The present invention has as a basis the realization that a filter unit allowing the making of tea or any other extraction drink directly in a thermos bottle must have a slender and narrow configuration to allow that the filter unit be mounted extending downwards into the interior of the thermos bottle, the latter having often, unlike teapots, relatively small openings determined in consideration of establishing a high thermal insulation between the interior of the thermos bottle and the ambient temperature. The filter units known from the above mentioned publications have thus all a configuration which prevents their use in

connection with thermos bottles, as well as the known disposable filter bags have exterior dimensions which prevent their use directly in connection with a thermos bottle for making tea.

In accordance with the teachings of the present inventions, the filter constitutes a construction comprising two components: a grip or handle component which, nevertheless, may constitute two separate units or, in specific configurations, an integrated construction which may further be geometrically configurated so that the grip or handle component and the tubular filter component continue substantially uninterrupted into each other. The definition of the grip or handle component and the tubular filter component refers thus in this context primarily to the function of the respective components and, more specifically, in the case of the handle component, to manoeuvering the filter unit, and, in the case of the tubular filter unit, to providing the filter unit itself which, thanks to the perforated outer wall component, allows the making of the extraction drink. In this connection, it is to be noticed that the tubular filter may have a larger or a smaller part of its outer wall perforated, the perforated outer wall being able to constitute a larger or a smaller part of the perforated filter component, the only condition necessary to be fulfilled being the functional requirement that the perforated outer wall allow diffusion of water in and out through the perforated part of the outer wall at the interior of the filter component.

In accordance with the presently preferred embodiment of the filter unit according to the present invention, the tubular filter component is configurated as a circular cylindrical filter component, and the perforated outer wall constitutes the circular cylindrical outer wall of the filter component. Thereby it is achieved a both functionally and aesthetically advantageous configuration which, on the one side, allows fulfilment of the requirements of geometric relations between the overall length of the tubular filter component and the largest exterior diameter, which make the basis of the present invention, and, on the other side, the functional requirements with a view to making an extraction drink using the tea leaves contained within the tubular filter component.

The filter unit according to the present invention may alternatively be shaped conical, i.e. the tubular filter component and, if necessary, the handle component may also be shaped conical, the smallest diameter of the conic filter component being defined by the first, closed end, and the largest outer diameter being defined by the second, open end.

The filter component of the filter unit according to the present invention may constitute an integrated unit or be composed of several components. In particular, the first, closed end of the filter component may thus be closed by an integrated or removable, perforated or massive end piece, the filter component constituting, in the case that the first, closed end is closed by an integrated, perforated or massive end piece, an integrated end piece, while in the case that the first, closed end is closed by a removable, perforated or massive end piece, the filter component is constituted by at least two components. The removable end piece may be coupled with the rest of the filter component by means of any known coupling means, such as hinges, press fits, spring locks or threads.

In accordance with alternative embodiments of the filter unit, the above mentioned end piece may constitute a disk shaped, plane end piece or be formed arched, preferably dome shaped, as the arched or dome shaped end piece may be mounted arched inwards or, preferably, outwards with respect to the interior space of the tubular filter component.

In the filter component according to the present invention the grip or handle component may be integrally formed with the tubular filter part in order to meet functional as well as aesthetic requirements or alternatively constitute a separate component relative to the tubular filter part.

The grip or handle component serves i.a., as described before, the object of facilitating the user the mounting of the filter unit on the thermos bottle or the similar recipient in which the extraction drink or the tea is to be made, and at the same time the object of facilitating the user the removal of the filter unit from the thermos bottle after use. To prevent the grip or handle unit from being heated to a temperature which would be unpleasant for the user, determined by the

boiling or scolding-hot water filled in the thermos bottle through the handle component and the interior space of the tubular filter component, the handle component is preferably made from thermally insulating material, preferably plastic, such as high temperature resistant plastic, or at least plastic which does not deform or soften at a temperature of approx. 100°C, i.e. the boiling point of water.

A series of known thermos bottles have a flange extending from the upper part of the thermos bottle upwards, which flange serves to keep a lid fixed in relation to the body of the thermos bottle. To ensure a correct and reliable emplacement of the filter unit relatively to such a thermos bottle, it is preferred that the handle component have a surrounding flange which extends parallel to the tubular filter component and is adapted to cooperate with the upwards extending flange of the thermos bottle or the similar recipient for keeping the filtering device fixed in relation to the thermos bottle.

In the presently preferred embodiment of the filter unit according to the present invention, the tubular filter is made from a thin stainless steel plate, and the perforated exterior wall component is constituted by a perforated part of the thin stainless steel plate, the perforations having a maximum opening diameter of less than 1 mm, preferably a maximum opening diameter of the order of magnitude 0.5 - 1.0 mm, such as 0.7 mm, thereby ensuring that the tea leaves are retained within the interior space and are not washed away through the perforations and into the thermos bottle, which could happen if the perforations had too large a diameter.

In accordance with an alternative embodiment of the filter unit according to the present invention, the tubular filter component is made by integral casting of a castable, temperature resistant material, preferably plastic, and the tubular filter component and the handle component are further in accordance with this alternative embodiment preferably cast in one piece by integral casting. In this integrally cast embodiment, the handle component and the tubular filter component may constitute conical elements which constitute sections of an overall, integrated body.

The present invention relates also to the a use of a filter unit according to the present invention, the use being characterized in that the filter unit is utilized in connection with a thermos bottle having a clearance width at the upper end of the thermos bottle which is less than 50 mm, such as 20-50 mm, e.g. 20-30 mm, 30-40 mm or 40-50 mm, preferably 35-50 mm, e.g. 35-45 mm.

In accordance with the use according to the present invention, the above mentioned embodiment of the filter unit according to the present invention, which embodiment is characterized in that it has a flange for cooperation with a flange extending upwards from the upper part of the thermos bottle, may advantageously be used in connection with such a thermos bottle which has the above mentioned upwards extending flange.

The invention will now be described in greater detail with reference to the accompanying drawings, in which:

Fig. 1 is a perspective, upper end view of a first and presently preferred embodiment of a tea filter according to the present invention,

Fig. 2 is a perspective, lower end view of the embodiment of Fig. 1,

Fig. 3 is a vertical cross-sectional view of the embodiment of Figs. 1 and 2,

Fig. 4 is a side view of the embodiment of Figs. 1-3,

Fig. 5 is a perspective view illustrating the intended use of the tea filter according to the present embodiment during making of tea in a thermos bottle or another similar recipient,

Fig. 6 is a perspective, upper end view of an embodiment of the tea filter according to the present invention, which is slightly modified in relation to the embodiment shown in Figs. 1-4, and

Fig. 7 is a perspective, lower end view of an alternative or third embodiment of the tea filter according to the present invention.

Figs. 1 and 2 show a presently preferred embodiment of a tea filter according to the invention, seen in perspective and from an upper end and a lower end, respectively. Terms like "upper" and "lower" end, i.e. terms defining a direction or an orientation, are to be construed only in relation to the intended use of the tea filter according to the invention, more specifically the use during which the tea filter is mounted on a thermos bottle or another recipient in which tea is made by extracting tea infusion from tea leaves which are received in the tea filter, and during which the thermos bottle or the similar recipient is placed in a substantially vertical position on a substantially horizontal table, thereby ensuring that the extraction drink does not spill over the brim of the thermos bottle or the similar recipient.

The tea filter 10 consists mainly of two components: a circular, cylindrical, perforated tube 12, the lower end of which is closed with a circular, likewise perforated disk 14 which is welded to the circular, cylindrical, perforated tube 12, and an annular grip or handle component 16 joined to the circular, cylindrical, perforated tube 12 at the upper end thereof. The circular, cylindrical, perforated tube 12 is preferably made of stainless steel, such as AISI 304 steel of a thickness of 0.7 mm. The perforations in the thin, stainless steel plate, from which the circular, cylindrical, perforated tube 12 is made, is preferably provided with circular perforations of a diameter of, for example, 0.7 mm, which are placed in a quadratic grid so that the centres of the perforations are placed in the nodal points of the quadratic grid and the grid interval is 2 mm. Alternative materials, for example other preferably corrosion resistant materials, such as platinum, gold, silver, nickel-plated copper, etc., may also be used, as well as other perforation sizes and perforation intervals.

The circular, cylindrical, perforated tube 12 which preferably has a length of, e.g. 142 mm, and a diameter of 33 mm is, as described above, closed at the lower end by means of a circular, perforated disk 14, preferably a disk likewise made of AISI 304 stainless steel with the same perforation configuration as the circular, cylindrical tube 12, but advantageously made with a larger thickness, for example 2 mm. In Fig. 1 and 2, the reference numeral 18 refers to a perforation in the circular, cylindrical tube 12, while the reference numeral 20 refers to a joint,

preferably a welded joint, between two margins of the thin, perforated, stainless steel plate, the circular, cylindrical tube 12 is made of, and in which the above mentioned quadratic grid is oriented with the connecting line placed between the nodal points of the quadratic grid and ortogonally in relation to the outer margins of the stainless steel plate.

The grip or handle component 16 is preferably made of a temperature resistant, thermally non-conducting material, such as a plastic material, which can resist light and thermal action. Examples of suitable materials are polymers, such as polyesthers, polycarbonates, polyalkyls, for example PP, PB (polypropylene, polybuthylene) or higher homologues or ramified variants thereof, ABS (acrylbutadienstyrene) or copolymers hereof, and, further, stainless steel which meets the above mentioned functional requirements. The grip or handle component 16 constitutes a substantially annular component mounted in a tight fit on the upper, open end of the circular, cylindrical, perforated tube 12 and forming from the upper, open end of the grip or handle component an inclined introduction surface 22 which leads from an upper, circumferential margin 24 of the handle component to the interior wall of the circular, cylindrical, perforated tube 12 and thus serves to lead the water poured into the tea filter 10 inside the circular, cylindrical, perforated tube 12. The handle component 16 is in the embodiment shown in Figs. 1-4 a specific thermos bottle and is thus formed at its lower part with a circumferential recess 26 for cooperating with an upwards extending, circumferential, circular flange of the respective thermos bottle.

Fig. 3 shows the first embodiment of a tea filter according to the invention also shown in Figs. 1 and 2, seen in a vertical cross-section view showing the above mentioned parts and components, especially the inclined introduction surface 22 and the circumferential recess 26 in the body of the handle 16. Correspondingly, Fig. 4 shows the above mentioned and presently preferred embodiment of the tea filter according to the invention, seen from one side.

Fig. 5 shows the intended use of the tea filter according to the present invention, more specifically the above mentioned use for making tea by

extraction of tea infusion from tea leaves received inside the tea filter. Thus, Fig. 5 shows the tea filter 10 with tea leaves placed at the lower end of the interior of the circular, cylindrical, perforated tube 12. The tea filter according to the present invention is especially adapted to and, unlike the known tea filters, allows making of tea in thermos bottles or other recipients with a very little opening, which limits heat emission from the interior of the thermos bottle or the recipient advantageously. The reference numeral 30 in Fig. 5 refers to a thermos bottle which may be of an arbitrary form, but has the general feature characteristic of thermos bottles, that the opening of the thermos bottles is of a small size compared to, for example, the opening in a conventional teapot. Whereas it is possible to make tea in teapots using several tea filter constructions of both the disposable and the reusable type, so far it has not been possible by means of known constructions of the disposable or the reusable type, to make tea directly in, for example, a thermos bottle or another recipient with a small opening, i.e. an opening with a diameter of less than 35-40 mm. Previously, it was first necessary to make the tea in a teapot and then to pour it from the teapot into a thermos bottle in which the tea could be kept warm due to the good thermal isolation of the thermos bottle determined by both the thermally insulated inner recipient and the limited size of the opening towards the interior of the thermos bottle through the upper opening thereof, which opening is closed by means of a cork or a similar closing device which, unlike the thermally insulated inner recipient of the thermos bottle, does not have entirely optimal thermal insulating characteristics and, consequently, in order to reduce the heat transfer from the interior of the thermos bottle, is built in the smallest possible size, but still taking into account an easy and safe handling of the thermos bottle, especially during pouring the extraction drink from inside the thermos bottle.

Fig. 6 shows, in accordance with Fig. 1, a second or alternative embodiment of the tea filter according to the present invention which second embodiment differs from the above mentioned embodiment described with reference to Fig. 1-4 in that the lower end of the tea filter is formed so that the tea filter may be opened for facilitating the cleaning of its interior by removing the used tea leaves from the interior of the tea filter after use.

In Fig. 6, the same reference numerals are used for the same components as in Fig. 4, whereas the components which differ from the components mentioned above with reference to Fig. 1-4 are designated the same reference numerals as in Fig. 1-4, but primed. Thus, the embodiment 10' shown in Fig. 6 differs from the embodiment described above in reference to Figs. 1-4 in that the circular, cylindrical, perforated tube 12' is shaped at its lower end with an exterior thread 13 which serves to cooperate with the interior thread 15 provided in a bottom or closing part 14' which may be mounted on and removed from the circular, cylindrical, perforated tube 12' by means of the cooperating threads 13 og 15. Further, the perforations 18' in the circular, cylindrical, perforated tube 12' are placed differently in relation to the pattern mentioned above in reference to Fig. 1-4, the quadratic net described by the perforations 18' extending at an angle of 45° in relation to the longitudinal axis of the circular, cylindrical, perforated tube 12'.

Fig. 7 shows an alternative or third embodiment of the tea filter according to the present invention. The third embodiment shown in Fig. 7 differs from de precedent embodiments described in reference to Fig. 1-4 and 6 in that the embodiment described in Fig. 7 and designated as a whole the reference numeral 40 is integrally cast from a corrosion resistant material, preferably plastic. Further, unlike the above mentioned embodiments in which it was included a circular, cylindrical, perforated tube, the integrally cast embodiment 40 comprises a perforated, slightly tapered, tubular central part 42 which at its lower end ends with a closed, dome-shaped end piece 44. Unlike the closed end piece 44, the slightly conical, perforated central part 42 is at its upper part connected to a circumferential, collar-shaped flange 46 which forms a component corresponding to the above mentioned grip or handle component which serves to allow the manipulation of the tea filter during use, i.e. during its lowering into and lifting out of a recipient, preferably a thermos bottle. The circumferential flange- shaped component 46 is further formed with a protruding grip eye 48. In order to allow the boiling water which is poured into the tea filter 40 to flow through the tea leaves contained in the interior of the filter and produce an infusion thereof and allow the water in the recipient, preferably the thermos bottle, to diffuse in the interior of the tea

filter, the slightly tapered, perforated central part 42 is formed with perforations, one of which being designated the reference numeral 50.

In the case that the perforated, tubular part is made from metal, the tea filter may, depending on the actual choice of material, be produced by means of techiques known per se comprising rolling, stamping, welding and soldering, whereas techniques well known per se for producing plastic and comprising injection moulding, blow moulding, etc., and eventual further processing may be used for producing the separate grip or handle component 16 described above in reference to Fig. 1-6, as well as for producing the integrated construction described above in reference to Fig. 7.

Although the invention described above has been described in reference to a series of embodiments of which those shown in Figs. 1-4 are the presently preferred, several modifications may be carried out within the limits of the present invention, as they are defined in the following patent claims, without departing from the spirit and the aim of the invention. Modifications of the present invention regarding both form and choice of materials may thus be carried out without departing from the spirit and the aim of the invention.

LIST OF REFERENCES

10 first and preferred embodiment of tea filter

12 circular, cylindrical, perforated tube

14 perforated circular disk

16 grip or handle component

18 perforation

20 joint

22 inclined surface

24 circumferential margin

26 circumferential recess

10' second or modified embodiment of the tea filter

12' circular, cylindrical, perforated tube

13 exterior thread

14' bottom or closing part

15 interior thread

18' perforation

30 thermos bottle

32 opening of thermos bottle

40 third embodiment

42 perforated, slightly tapered, tubular central part

44 closed, dome-shaped end piece

46 circumferential flange

48 protruding grip eye

50 perforation