WO1990009131A1

WO1990009131A1 - Microwave brewing apparatus and method therefor

Info

Publication number: WO1990009131A1
Application number: PCT/CA1990/000045
Authority: WO
Inventors: Dong Yu
Original assignee: Micro Cafe Inc.
Priority date: 1989-02-16
Filing date: 1990-02-15
Publication date: 1990-08-23
Also published as: AU5103390A

Abstract

A method of making a beverage from an infusible material in a microwave oven, employing an apparatus having a microwave transparent pressurizable liquid reservoir, a filter chamber adapted to hold a quantity of the infusible material, said filter chamber mountable above a beverage receptacle, the pressurizable liquid reservoir in fluid communication with the filter chamber, the method comprising placing a supply of an infusible material in the filter chamber, closing said filter chamber, pouring a liquid into the pressurizable liquid reservoir to a level below the top of the liquid reservoir, closing said pressurizable liquid reservoir, heating said liquid in said pressurizable liquid reservoir with microwave energy to raise the vapor pressure in the pressurizable liquid reservoir sufficiently to force said liquid from the pressurizable liquid reservoir through the fluid communication means into the filter chamber to make a beverage, and collecting the beverage in said receptacle.

Description

MICROWAVE BREWING APPARATUS AND METHOD TflfeREFOR

A method of making a beverage from an infusible material in a microwave oven, employing an apparatus having a microwave transparent pressurizable liquid reservoir, a filter chamber adapted to hold a "quantity of the infusible material, said filter chamber mountable above a beverage receptacle, the pressurizable liquid reservoir being mounted bove or beside said filter chamber and in fluid communication with the filter chamber; the method comprising placing a supply of an infusible material in the filter chamber, closing said filter chamber, pouring §. liquid into the pressurizable liquid reservoir, closing said pressurizable liquid reservoir, heating said liquid in said pressurizable liquid reservoir with microwave energy to raise the liquid vapor pressure in the pressurizable liquid reservoir sufficiently to force said liquid from the pressurizable liquid reservoir into the filter chamber to make a beverage, and collecting the beverage in said receptacle.

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for brewing coffee, tea or other beverages from respective infusible materials using microwave energy, and to a method of making such beverages.

Microwave coffee makers are known in the art. U.S. Patent No. 4,104,957 issued to Freedman et al. discloses a drip-type appliance containing a thermally controlled valve in a microwave transparent water reservoir which is positioned over a coffee compartment which in turn is placed above a receptacle. For use, the reservoir is filled with an amount of water, ground coffee is placed on the filter in the coffee compartment, the appliance is placed in a microwave oven and the oven is operated for a selected period of time. When the temperature of water reaches a predetermined level, the valve opens allowing the heated water to flow down through the coffee grounds.

U.S. Patent No. 4,381,696 issued to Koral proposes a similar solution except for the valve between the water reservoir and the coffee compartment being manually operated. After water has been placed in the reservoir, the valve is opened manually immediately before or during the activation of the microwave oven with the coffee maker disposed therein. U.S. Patent No. 4,386,109 issued to Bowen et al. teaches an expresso-type coffee maker for use in a microwave oven. Water is stored in a microwave transparent reservoir which is separated from a receptacle by a layer of coffee grounds placed over a strainer. The coffee layer is compressed and forms a pressure resistant seal over the water outlet from the reservoir. When the water in the reservoir is heated by microwave energy the pressure in the reservoir rises to a level sufficient to force steam and water through the coffee layer into the receptacle.

Another drip-type coffee maker is described in U.S. Patent No. 4,577,080 to Grossman. The maker comprises a water container positioned above a coffee compartment which is separated from the container by a partition. The partition has perforations sealed with a thermally responsive material that melts when the water is heated to the desired temperature in the microwave oven, allowing the heated water to flow from the upper reservoir through the coffee grounds into a receptacle placed below the coffee maker.

The latter design is apparently intended to be a disposable coffee maker.

It will be appreciated that these and similar microwave coffee makers can be designed to prepare small quantities of coffee, such as a single cup, or to brew larger quantities. In any case, their dimensions, of course, must be such as to allow the appliances to be accommodated in an average microwave oven. While the above-described microwave coffee makers are useful, there is still a need for a simple and reliable drip-type brewing appliance for use in a microwave oven, the appliance not employing complicated mechanical units such as opening valves or pressure relief valves, and suitable for repeated use.

STATEMENT OF THE INVENTION

According to the present invention, there is provided an apparatus for brewing coffee, tea or a similar beverage from a respective infusible material i.e. ground coffee beans, tea leaves, etc., using a typical microwave oven. In one embodiment the apparatus is adapted to be placed over a coffee mug, a cup or a beverage receptacle with an open upper end and comprises a microwave transparent filter chamber having a filter positioned in a bottom part thereof, the filter adapted for holding a quantity of an infusible material and for the dispensing of a brewed beverage therefrom into the receptacle, and a pressurizable liquid reservoir adapted to hold a quantity of a liquid up to a predetermined level, the pressurizable liquid reservoir being in fluid communication with the filter chamber through overflow means which is adapted to hold the liquid within the pressurizable liquid reservoir until pressure in the pressurizable liquid reservoir rises sufficiently to force the liquid through the overflow means into the filter chamber.

In another embodiment of the invention the apparatus consists of a vessel for brewing one or more cups of coffee. The beverage receptacle and the pressurizable liquid reservoir may be formed from two parts of a single vessel divided by a common wall. A microwave transparent filter chamber having a filter positioned in a bottom part thereof is inserted in the top of the beverage receptacle. The pressurizable liquid reservoir is in fluid communication with the filter chamber through an overflow means which transfers liquid under pressure from the liquid reservoir to the filter and finally to the beverage receptacle.

Pressure overflow means are known in various fields of technology. Most commonly, such means are employed in a sink drain wherein two columns of water stay at the same level until additional hydrostatic pressure is exerted onto one column making the liquid from the other column overflow to the disposal system. In one embodiment of the apparatus, the pressure overflow means comprises an overflow conduit which extends upwardly from near the bottom of the reservoir and downwardly through the top of the filter chamber, connecting the reservoir with the filter chamber. In operation, the filter chamber is placed on the cup or beverage receptacle, a supply of infusible material is placed in the filter chamber, the filter chamber is closed, liquid is poured into the pressurizable liquid reservoir to a level below the top of the pressurizable liquid reservoir, the pressurizable liquid reservoir is closed, the liquid in said pressurizable liquid reservoir is heated with microwave energy to raise the vapor pressure in the pressurizable liquid reservoir sufficiently to force said liquid from the pressurizable liquid reservoir through the fluid communication means into the filter chamber to make a beverage which is collected in the cup or receptacle.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which illustrate embodiments of the present invention,

Figure 1 is a vertical sectional view of one embodiment of the apparatus in which the fluid connection is comprised of an inverted U-tube. Figure 2 is a vertical sectional view of another embodiment of the apparatus in which the fluid reservoir is beside the receptacle. Figure 3 is a vertical sectional view of another embodiment of the invention in which the fluid ^r • connection is formed of two tubes.

Referring particularly to Figure 1, the pressurizable liquid reservoir 10 has an inner wall 22 to receive the filter chamber 12. The inner wall 22 may provide frictional engagement with the wall of the filter chamber 12, as shown in Figure 1, or a threaded connection may be employed, using threads 24 and 26 not shown. The pressurizable liquid reservoir 10 is supported on receptacle 38. A cap 14 containing internal threads 18 engageable with threads 20-on the exterior of the pressurizable liquid reservoir 10 enables the cap 14 to be firmly fastened to *6 e top of pressurizable liquid reservoir 10. While threads have been shown in Figure 1 other known fastening means may also be used to fasten cap 14 to pressurizable^"liquid reservoir 10.

The filter chamber 12 has a concave bottom 32 with a metal filter 34 molded therein. The metal filter 34 has perforations of a size adapted to retain the particles of an infusible material, e.g. coffee grounds, and to allow the passage of a liquid therethrough. The filter chamber 12 also has an exterior wall 36 of a size adapted to frictionally engage most of inner wall 22 of pressurizable liquid reservoir 10. It is preferable to provide a small passage 39 between the receptacle 38 and the outward extensions 40 at the base of filter chamber 12 for excess steam to escape. The small passage 39 may be at a point or points in the outward extension of ~tfϊe base of filter chamber 12. An annular lip 41 is provided on the underside of the filter chamber 12, which serves as an abutment element for safe positioning of the apparatus over the receptacle 38. The concavity of the bottom of the filter chamber 12 helps to keep the flow of liquid from the chamber close to the centre of the filter chamber 12. The filter chamber and pressurizable liquid reservoir may in one embodiment be used with any receptacle 38. It is preferable, however, that the receptacle 38 is of a microwave transparent variety. When the pressurizable liquid reservoir 10 is filled with water up to a predetermined level as indicated in Figure 1, the water is prevented from flowing downwards into the chamber 12 by an inverted U- tube 43 (Figure 1) . As shown in Figures 1 and 2, the U-tube 43 has one leg 51 which is disposed below the water level. Consequently, water rises in the right hand side leg of the U-tube only, as seen in the drawing, through the open end 52 of the U-tube 43. The downward leg 54 of inverted U-tube 43 is open to filter chamber 14 through an opening 55 in the central raised portion 53 of the reservoir 10.

In the embodiment illustrated in Figure 1, the pressurizable liquid reservoir 10, the cap 14 and the filter chamber 12 (except the filter) are made of polycarbonate, a microwave transparent plastic resistant to the boiling water temperature. Alternatively, other microwave transparent materials, well known in the art, may be employed. The receptacle 38 could be made of a microwave semi-transparent material so that in use, the liquid in the receptacle 38 is heated more slowly than in the pressurizable liquid reservoir 10.

Referring to Figure 2, the pressurizable liquid reservoir 10 is formed side by side with receptacle 38. The filter chamber 12 is designed to be supported in the top of receptacle 38 when in use and to be removed therefrom when the beverage is removed from receptacle 38. The inverted U-tube 43 is inserted through cap 14 of pressurizable liquid reservoir 10 so that the bottom 52 of down leg 51 is positioned near the bottom of pressurizable liquid reservoir 10. The opposite leg 54 of inverted U-tube 43 is friction fitted through the opening 55 in the cap or closure 53 of filter chamber 12.

To prepare to use, the apparatus is disassembled. A quantity of coffee grounds, for example, is placed in the filter chamber 12 and cap 53 is placed on the filter chamber. The pressurizable liquid reservoir 10 is filled with water equal to the desired amount of beverage. The pressurizable liquid reservoir 10 is then closed with the cap 14. One end of U-tube 43 is placed through orifice 61 in cap 14 and the U-tube 43 is lowered in pressurizable liquid reservoir 10 until the bottom 52 of U-tube 43 is near the bottom of pressurizable liquid reservoir 10. The opposite end of U-tube 43 is placed through the orifice 55 in closure 53 of filter 12. The apparatus is placed in a microwave oven.

Referring now to the embodiment of Figures 1 and 2, when the water in the pressurizable liquid reservoir 10 is heated by microwave energy, the vapor pressure in the pressurizable liquid reservoir 10 rises and forces the water through the U-tube 43 and through the downward leg 54 into the filter chamber 12. This operation continues until the water level in the pressurizable liquid reservoir 10 drops to the level of the bottom end 52 of U-tube 43. The heated water flows into the filter chamber 12 and through the coffee grounds, and then through the filter chamber 34 into the receptacle 38.

For manufacturing convenience, the U-tube 43 may be manufactured separately and may be friction fitted through cap or closure 53 or in the alternative may be f stened to one or other of the cap or closure 53.

While a single cup beverage brewing apparatus is shown in Figure 1, it is to be appreciated that the beverage brewing apparatus of the type shown in Figure 2 may be employed to make two or more cups of coffee, the restriction on the number of cups of coffee depending only on the dimensions and power of the microwave oven in which the apparatus is proposed to be used.

As shown in Figure 3, the upper edge of a tube 42 extends above the water level. An external tube 44, concentric with tube 42, depends from the cap 14 so that it overlaps most of the length of tube 42 and extends close to the bottom of the reservoir 10 when the cap 14 is secured to the reservoir 10.

As shown in Figure 3, the external tube 44 and the overflow tube 42 define an external annular passage 46 and an internal tubular passage 48.

Referring to Figure 3, when the reservoir is filled with water up to a predetermined level as indicated in the drawings, the water is prevented from flowing downwards into the chamber 12 by the overflow tube 42 (Figure 3) aligned with the respective openings 28 at the bottom of the reservoir 10. In operation the pressurizable liquid reservoir 10 operates in the same fashion as the pressurizable liquid reservoir 10 of Figure 1.

Claims

1. A method of making a beverage from an infusible material in a microwave oven, employing an apparatus having a microwave transparent pressurizable liquid reservoir, a filter chamber adapted to hold a quantity of the infusible material, said filter chamber mountable above a beverage receptacle, the pressurizable liquid reservoir in fluid communication with the filter chamber, the method comprising: placing a supply of an infusible material in the filter chamber, closing said filter chamber, pouring a liquid into the pressurizable liquid reservoir to a level below the top of the liquid reservoir, closing said pressurizable liquid reservoir, heating said liquid in said pressurizable iiquid reservoir with microwave energy to raise the vapor pressure in the pressurizable liquid reservoir sufficiently to force said liquid from the pressurizable liquid reservoir through the fluid communication means into the filter chamber to make a beverage, and collecting the beverage in said receptacle.

2. The method of claim 1 in which the fluid communication means between the transparent pressurizable liquid reservoir and the filter chamber is an inverted tube having one leg mounted near the bottom of the pressurizable liquid reservoir and the other leg is connected with the filter chamber.

3. The method of claim 1 in which the fluid communication means between the transparent pressurizable liquid resrvoir and the filter chamber is comprised of an inner tube extending upwardly from the base of the reservoir to a point below the top of the reservoir and an outer concentric tube extending downwardly from the cap of the reservoir to a point above the bottom of the reservoir.

4. The method of claim 1 or 2 in which the infusible material is coffee and the liquid is water.

5. The method of claim 1 or 2 in which the infusible material is tea and the liquid is water.

6. A method of making a beverage from an infusible material in a microwave oven, employing an apparatus having a microwave transparent pressurizable liquid reservoir, a filter chamber adapted to hold a quantity of the infusible material, said filter chamber mountable above a beverage receptacle, the pressurizable liquid reservoir being beside or below said filter chamber and in fluid communication with the filter chamber, through an inverted tube having one leg mounted near the bottom of the pressurizable liquid reservoir and the other leg mounted in the filter chamber; the method comprising: placing a supply of an infusible material in the filter chamber, closing said filter chamber, pouring a liquid into the pressurizable liquid reservoir to a level below the top of the liquid reservoir, closing said pressurizable liquid reservoir, heating said liquid in said pressurizable liquid reservoir with microwave energy to raise the liquid vapor pressure in the pressurizable liquid reservoir sufficiently to force said liquid from the pressurizable liquid reservoir through the fluid communication means into the filter chamber to make a beverage, and collecting the beverage in said receptacle.

7. A beverage brewing apparatus for use in a microwave oven, comprising a beverage receptacle, a filter chamber and a pressurizable liquid reservoir, the filter chamber adapted to hold a quantity of infusible material and adapted to be placed over the beverage receptacle, the pressurizable liquid reservoir in fluid communication with the filter chamber.

8. The beverage brewing apparatus of claim 7 wherein the fluid communication connecting said pressurizable liquid reservoir to said filter chamber comprises an inverted U-tube, one end of the U-tube being positioned near the bottom of the pressurizable liquid reservoir, the open distal end of the U-tube in fluid communication with the filter chamber.

9. The beverage brewing apparatus of claim 7 in which the fluid communication means between the transparent pressurizable liquid resrvoir and the filter chamber is comprised of an inner tube extending upwardly from the base of the reservoir to a point below the top of the reservoir and an outer concentric tube extending downwardly from the cap of the reservoir to a point above the bottom of the reservoir.

10. The beverage brewing apparatus of claim 7 in which the beverage receptacle and pressurizable liquid reservoir are part of a single vessel.

11. A beverage brewing apparatus for use in a microwave oven, comprising a beverage receptacle,^*a filter chamber and a pressurizable liquid reservoir, the filter chamber adapted to hold a quantity of infusible material and adapted to be placed over the beverage receptacle, the pressurizable liquid reservoir is beside said beverage receptacle and in fluid communication with the filter chamber through an inverted tube having one leg mounted near the bottom of said pressurizable liquid reservoir and the other leg mounted above the filter chamber.