WO2004026090A1

WO2004026090A1 - A piston for a piston jug for beverages

Info

Publication number: WO2004026090A1
Application number: PCT/DK2002/000607
Authority: WO
Inventors: Carsten Jørgensen
Original assignee: Pi-Design Ag
Priority date: 2002-09-18
Filing date: 2002-09-18
Publication date: 2004-04-01
Also published as: AU2002342570A1; TW200406168A; TWI230049B

Abstract

A piston for a piston jug for beverages, particularly a piston coffee maker, with a cylindrical container (1) with a lid (4) holding in a central opening a piston rod (3) carrying a handle (5) on the top above the lid (4) and at the lower end a piston (2) provided with spokes (21) and a filter (23) and a flexible sealing (20) against the wall of the coffee maker causes some drawbacks when used for preparing tea. This has some disadvantages in that the filter portion (23) of the piston can not establish a perfect separation between the tealeaves and the drinking liquid, which further, has as a consequence, that the tea liquid will deteriorate as the bitter components will be released from the tealeaves during the continued infusion and mix with the drinking liquid. It is therefore a goal for the inventor to establish such a barrier between the tealeaves and the tea liquid that further infusion will be prevented. To this end the inventor has suggested, that the piston (2) on the upper side is equipped with a soft, preferably resilient membrane (25) supported on the upper side by a set of at least two spokes (81), which are combined in a hub (83) fastened around the piston rod (3).

Description

A PISTON FOR A PISTON JUG FOR BEVERAGES

TECHNICAL FIELD

[0001] The present invention relates to a piston for a piston jug for beverages, particularly a piston coffee maker, with a cylindrical container with a lid holding in a cen- tral opening a piston rod carrying a handle on the top above the lid and at the lower end a piston fastened by nuts and provided with spokes and a filter and a flexible sealing against the wall of the coffee maker.

PRIOR ART TECHNIQUE

[0002] Such piston jugs are widely known, and they all have the features of the above-mentioned piston jug in common. The piston, when being pressed down, will separate particles suspended in the drinking liquid from the drinking liquid thereby ending the infusion.

[0003] It has for long time been suggested also to use such coffee maker for preparing tea, but this has some disadvantages in that the filter portion of the piston can not establish a perfect separation between the tealeaves and the drinking liquid, which has as a consequence, that the tea liquid will deteriorate as the bitter components will be released from the tealeaves during the continued infusion and mix with the drinking liquid.

SUMMARY OF THE INVENTION [0004] The inventor has, therefore, as a goal to establish such a barrier between the tealeaves and the tea liquid that further infusion will be prevented. [0005] To this end the inventor has suggested that the piston on the upper side is equipped with a soft, preferably resilient membrane supported on the upper side by a set of at least three spokes, which are combined in a hub fastened around the piston rod. With such arrangement, the piston can be pressed down ending the infusion, whereby the soft membrane will yield to the higher pressure under the piston and let the drinking liquid pass the filter and the soft membrane. Having reached the lower stop for the piston the higher pressure under the piston will be equalised with the pressure on the upper side of the piston through the open soft membrane, and the pressure gradient will dis- appear. When the pressure gradient has disappeared, the soft membrane will rest against the spokes of the piston and thereby close any fluid connection between the lower and the upper side of the piston. Pn this way, the infusion that might continue below the piston, will not influence the tea liquid above the piston, and the tea will not deteriorate due to the bitter components that might be the result of a continued infusion below the piston.

[0006] Having achieved an effective termination of the infusion with the piston according to the invention, the next step for the inventor was to remove the piston from the bottom of the container for the preparation of another pot of tea. To this end the inventor has suggested that the resilient membrane towards the centre of the piston has at least one tongue covering a corresponding number of openings in the hub of the spokes above the membrane, and that the tongues when lifting off are reaching down between the spokes of the basic piston. With this arrangement, it is achieved that lifting the piston from the bottom will cause the tongues in the membrane to lift off from the hub and thus allow for a pressure equalisation. [0007] In order to secure the membrane and the tongues in relation to the hub above and the corresponding openings the spokes have suitable locking means, which cooperate with corresponding locking means in or on the membrane. In a preferred embodiment of the locking means, protrusions are reaching down from the hub into corresponding openings in the membrane. In this way, any sliding of the membrane can be avoided and the proper function of the membrane in relation to the hub and spokes is secured.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The invention is described more clearly in the drawings, where the fig. 1. shows a sectional view of a typical piston coffee maker with a piston according to the invention, and fig. 2. shows an exploded view of the piston and its parts according to the invention, DETAILED DESCRIPTION OF THE INVENTION

[0009] The function of the piston 2 can be illustrated by way of an example presented in the fig. 1. When preparing a pot of tea water must be boiled. During the boiling the lid 4 and the piston 2 with the piston rod 3 are removed and tealeaves are filled into the container 1. When the water is boiling it is poured into the container 1 and the lid 4 with the piston 2 in a lifted position is put on the container 1. [0010] After the proper infusion time, normally ranging from five to fifteen minutes, the piston 2 is pushed down by pressing down the handle 5 and the piston rod 3. During the downwards movement a pressure is built up below the piston 2 and this pressure causes the membrane 25 to be lifted off from the piston ring 22 thereby minimising the pressure gradient. When the piston 2 has been pushed down to the lower position, the movement will stop and the membrane 25 will again rest against the piston ring 22 and shut off any fluid connection between the two sides of the piston 2. [0011] When the tea jug is empty the piston 2 must be removed in order to change the contents of the tealeaves. This time, a vacuum will build up below the piston 2 when attempting to lift the piston 2. In order to equalise the pressure the tongues 27 of the membrane 25 now will lift off from the hub 83 thereby minimising the vacuum or pressure gradient between the two sides of the piston 2. Having removed the piston 2 and the lid 4 the container 1 can be cleaned and is ready for another preparation of tea. [0012] The material chosen for the various parts of the piston is preferably polycarbonate PC or POM for the hub 83 and the spokes 81 above the membrane 25, which preferably is made of resilient silicone. All other materials are already well known and have been used for several decades.

Claims

PATENT CLAIMS

1. A piston for a piston jug for beverages, particularly a piston coffee maker, with a cylindrical container (1) with a lid (4) holding in a central opening a piston rod (3) car- rying a handle (5) on the top above the lid (4) and at the lower end a piston (2) provided with spokes (21) and a filter (23) and a flexible sealing (20) against the wall of the coffee maker, characterised in that the piston (2) on the upper side is equipped with a soft, preferably resilient membrane (25) supported on the upper side by a set of at least two spokes (81), which are combined in a hub (83) fastened around the piston rod (3).

2. A piston according to claim 1, characterised in that the resilient membrane (25) towards the centre of the piston (2) has at least one tongue (27) covering a corresponding number of openings (26) in the hub (83) of the spokes (81) above the membrane (25), and that the tongues when lifting off are reaching down between the spokes (21) of the basic piston (2).

3. A piston according to claim 1 - 2, characterised in that the spokes (81) have suitable locking means (82) which co-operate with corresponding locking means (26) in or on the membrane.

4. A piston according to claim 3, characterised in that protrusions (82) are reach- ing down from the spokes (81) into corresponding openings (26) in the membrane (25).