GB2059753A

GB2059753A - Beverage making apparatus

Info

Publication number: GB2059753A
Application number: GB8016468A
Authority: GB
Original assignee: Still & Sons Ltd W M
Current assignee: Still & Sons Ltd W M
Priority date: 1979-05-18
Filing date: 1979-05-18
Publication date: 1981-04-29
Also published as: GB2059753B

Abstract

This invention relates to coffee or tea making or brewing apparatus and especially to apparatus of the type in which heated water is caused to flow through a spray head, the resulting spray impinging on a bed of ground coffee (or tea) through which the hot water passes to produce coffee or tea liquor. Conventionally apparatus of this type has a heated tank connected both to a water inlet and to the spray head. In accordance with this invention the heated tank 10 is located beneath the spray head 18 and the heater for the tank is energised only when water is introduced into the apparatus. The heater then heats water in the tank causing the water to boil, the steam pressure produced acting to cause the water to flow up the tank to the spray head. This helps to achieve a consistency of brewed coffee as the water is always at or only just below boiling point when it impinges on the coffee. <IMAGE>

Description

SPECIFICATION Improvements in and relating to coffee and tea rmnak- ing or brewing apparatus This invention relates to coffee or tea making or brewing apparatus and especially to apparatus of the type in which heated water is caused to flow through a spray head, the resulting spray impinging on a bed of ground coffee (or tea) through which the hot water passes to produce coffee or tea liquor.

Conventionally apparatus of this type has a heated tank connected both to a water inlet and to the spray head.

Water in the tank is maintained at a high temperature by the heater and is maintained by a thermostat at a temperature and introduction of a measured quantity of cold water th rough the inlet acts to displace an equal quantity of hot water to the spray head. In this type of apparatus the water is not heated to boiling point and the flow of water to the spray head is achived by gravity.

An alternative proposal is to provide a heater which is energised during use and into which cold water is introduced through an inlet passage, the water being heated during its passage through the heater and then flowing to the spray head under gravity. This apparatus suffers from the far . that the water reaching the spray head is nat necassarily at boiling temperature, the heater is constantly energised and, as it has to heat the water during its passage through the heater under the effect of gravity, is of high energy consumption.

Coffee or tea making or brewing apparatus in accordance with this invention has a heated container unit or the like, connected, to a source of, or reservoir for, cold or unheated water and, to a spray head from which heated water is sprayed over a bed of coffee, the heater for r the container being ener- gised when water is introduced into the inlet and acting to heat water in the tank to such a temperature as to produce steam, the pressure of which then acts to force heated water through the outlet to the spray head. The container may be in the form of a small tank, or convoluted passage so that the water is heated quickly. No thermostat is provided as the heater is preferably de-energised when the container is empty.

This helps considerably in achieving satisfactory consistency of brewed coffee (or tea) as the consis tency depends on The the temperature of water imping- ing on the bed of coffee. With the apparatus of the invention, water is always at, or only just below, boiling point when it impinges on the coffee as it is the steam formed inside the heated container or unit which causes the necessary pressure to move the water from the heater to the spray head and to then flow through the spray head.This provides a significant advantage as compared with conventional apparatus in which the temperature of water being sprayed on the coffee (or tea) bed depends on the initial ambient temperature of water being fed to the heater whereas in the arrangement of the invention, the temperature of water impinging on the coffee bed is independent of the temperature of water supplied to the heater.

An inlet water reservoir is provided positioned above the heated tank, switch means e.g. a float switch, being provided to energisethe heater for the heated tank when, and only when, water is present in the inlet reservoir.

Water may be introduced into the inlet reservoir either manually from a flask or the like or the reservoir may be connected to mains supply, switch means preferably being provided to close the connection to the mains supply when the reservoir is full.

The, or part of the, inlet water reservoir is preferably positioned above the spray head so that the head of water assists, but doesn't cause, flow of hot water from the heated tank to the spray head.

More than one heater unit can be employed to increase output but each heater is preferably formed of a metal bock, such as aluminium, having a "castin" heating element(s) which is located adjacent to or forms part of a wall of the water "tank".

The spray head may be in accordance with our co-pending Application No. 80 16467 filed simultaneously herewith and be provided with a number of dimples each head of a dimple being provided or formed with a surface to which a drop of water passing through a spray hole in the centre of the dimple, may cling.

Water drops tend to adhere to the underneath of the portion of the dimple around each spray hole by surface tension and droplets are thus formed beneath each dimple which fall over the coffee (or tea) bed in the infuser in a random fashion which may be compared with raindrops. This helps to prevent nuclei being formed in the coffee bed. The frequency of droplets can be adjusted by varying the flow of water to the heater and/or the flow of water from the heater to the spray head so as not to allow the coffee bed to be flooded or cause the bed to be lifted.

The invention will now be further described by way of example with reference to the accompanying sketch drawing, in which: Figure 1 is a schematic side elevation of one embodiment of coffee making apparatus in accordance with the invention, Figure2 is a section through a part of the spray head on an enlarged scale, Figure 3 is a section on the line A-A of Figure 1 illustrating further features of the heated tank unit and Figure 4 is a view similar to Figure 1 but showing the apparatus adapted for connexion to mains water supply.

Referring to Figure 1, the coffee making apparatus comprises a casing or body 2 having an internal cold water tank or reservoir4 positioned at its top and having an inlet 6 through the top of the casing 2 to receive cold water from a flask, which inlet ray be closed by cover C.

The cold water tank 4 is connected to an inlet 8 of a heated tank unit generally indicated E 10, by means of a pipe 12. The heated water flows from the heater through an outlet 14to a pipe 16 which passes up adjacent the cold water tank 4 and connects with a spray head 18 positioned above the coffee infuser basket 20. The basket is lined with a removable filter paper 22 on which is positioned a bed of ground coffee 24. As is conventional, the infuser basket 20 can be lifted out from the apparatus using its handle 26, for replacement of the filter paper and bed of OaifSe.

The infuser basket is approximately concal in shape tapering to an outlet hole 28 positioned above a flask 30 to receive coffee liquor which is formed by hot water passing from the spray head 18 through the bed 24 of ground coffee. Coffee in the flask 30 is kept warm by a conventional heater unit 32 on which the flask sits. Equally, a warming plate 34 for a second storage flask is located at the top of the machine.

The spray head 18 is formed with a series of dimples 36 extending downwardly from its bottom face each dimple having a flat head 38 as can readily be seen in Figure 2, the flat head of each dimple being pierced by a centrally positioned spray hole 40. In use, water flowing to the spray head through the pipe 16 fills the head and also the interior of the various dimples. The water then passes through the spray holes 40 to form droplets 42 which it is believed adhere, during their formation, to the flat portion of the dimples around the spray holes due to surface tension. When a droplet reaches a certain size and weight, it detaches itself from the dimple to drop to the coffee bed as illustrated at 42' in Figure 2.

It has been found that the droplets fall in a random fashion from the spray head over the coffee bed in a manner akin to raindrops and that this provides very effective overall infusion as compared with that which is produced when a concentrated stream of liquid impinges on the bed at a specific point from each of several spray holes in a flat plate.

This arrangement helps to produce a consistent brew and the consistency of brew is aided by a provision of a heater such as that illustrated at 10 which avoids the use of any separate water pump and which supplies water to the spray head at a consistent temperature.

As can be seen in Figure 3, cold water flows into the heated tank unit 10 through inlet 12 and into the interior which communicate with the heater outlet 14 and water flow pipe 16.

The heater comprises a cast block 46 of aluminium which provides one side face of the water tank 44 and which has a heating element 48 embedded therein so that water in the tank is heated by the element 48 through the medium of the cast metal block 46. Water flowing through the heater is heated by the heating element 48 to a temperature at which steam is produced irrespective of its temperature at the inlet. The production of steam creates pressure to cause water at, or only just below, boiling point, to flow up through the delivery tube 16 to the spray head 18. This has the advantage that the water falling on the coffee bed is always at a consistent temperature at, or just beiow, boiling point which temperature is ideal for the brewing of eithertea or coffee.

The tank has a cover plate 49 which is attached to the block 46 by a screw and which can readily be removed for cleaning and descaling.

No thermostat is provided, although a high temperature safety cut-out may be incorporated in the heaterto protect the heating elements. However, the heating element is not energised until a level switch 50 located in the passage between the cold water reservoir 4 and heated tank 10 is closed (it is shown open in Figure 1 for clarity although it would in fact be closed if the reservoir 4 contains water). Thus, so long as there is water in the tank 4, the heater is energised and water will flow from the spray head 18. Once the tank is empty, the level switch 50 will open and the heater 48 switched off to save energy.

This means that fresh water is employed each time the machine is used for brewing as there is no storage of water in the tank.

It will II be appreciated that the apparatus could incorporate more than one heated tank unit 10 and indeed different embodiments of heater could be used.

It will be appreciated that whilst the invention has been described with a specific reference to apparatus of the type in which the provision of a specified amount of water to the machine through the inlet, causes an equivalent amount of coffee liquorto be produced, the invention could equally well be embodied in apparatus which is adapted to be "plumbed-in" to a consistent supply in which case a metered amount of cold water is introduced to the cold water tank. Such an apparatus is illustrated in Figure 4. As can be seen the inlet tank or reservoir4 is connected through an inlet pipe 52 through a solenoid valve 54 to a connection 56 for cold water mains supply.On depression of a push button switch 58, the valve 54 is opened allowing cold mains water to enter the inlet tank or reservoir 4 until the level of water rises to reach an upper level probe switch 60. By this time the heated tank 10 is flooded and the heater 48 is energised when the water level reaches the probe 60. At the same time the valve 54 is closed.

The water in tank 50 in then boiled and discharged through the spray head as previously described.

When the water level in the tank 4 drops to the level of the lower probe 62, the control unit 64 is isolated and when the level drops to that of the float switch 50, the switch falls to the empty position as shown in Figure 4 cutting off electrical supply to the heater 48.

It will be appreciated that the volumes of the heatertank and inlet tank up to the upper probe level is equivalent to a full flask 30.

Claims

1. Coffeeortea making or brewing apparatus comprising a container or the like provided with a heater to heat the liquid in the container, the container being connected both to a source of, or reservoir for, relatively cold inlet liquid, and to a spray head located above the tank and from which heated liquid may be sprayed over a bed of coffee (ortee), the container heater being energised when inlet liquid is introduced into the apparatus and being capable of heating liquid in the container to such a temperature as to produce steam, the pressure of which then being sufficient to force heated liquid up to the spray head.

2. Coffee or tea making or brewing apparatus as claimed in claim 1 in which an inlet liquid (water) reservoir is provided above the container, switch means being provided to energise the heater when, and only when, liquid is present in the reservoir.

3. Coffee or tea making or brewing apparatus as claimed in Claim 2 wherein the connection between the container and the spray head extends above the predetermined upper level of liquid in the reservoir.

4. Coffee or tea making or brewing apparatus as claimed in any of the preceding claims incorporating more than one heated container.

5. Coffee or tea making or brewing apparatus as claimed in any of the preceding claims in which the, or each, heater comprises a metal block having a heating element incorporated therein.

6. Coffee or tea making or brewing apparatus as claimed in any of the preceding claims wherein an inlet water reservoir is provided above the container, the reservoir being provided with a connection for mains water supply, through a valve which is closed automatically when the level of water in the reservoir reaches a predetermined height.

7. Coffee or tea making or brewing apparatus as claimed in any of the preceding claims wherein the container connection to the liquid inlet is situated at or adjacent the bottom wall of the container and the connection to the spray head is located at or adjacent the top of the container.

8. Coffee or tea making or brewing apparatus as clamed in any of the preceding claims wherein the heater for the container is not controlled by a thermostat.

9. Coffee or tea making or brewing apparatus as claimed in any of the preceding claims substantially as hereinbefore described with reference to Figures 1-3 or Figure 4 of the accompanying drawings.