EP3232879A1

EP3232879A1 - Method and device for brewing a beverage

Info

Publication number: EP3232879A1
Application number: EP15790991.2A
Authority: EP
Inventors: Robert David TOLFTS
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2014-12-19
Filing date: 2015-11-09
Publication date: 2017-10-25
Also published as: AR103066A1; WO2016096247A1

Abstract

A method of starting-up a pump for providing a flow of liquid in a brewing device, the method involving applying a target voltage to the pump in order to achieve a target flow rate, the method involving employing a start-up controller adapted to apply an excess voltage, in excess of the target voltage, and in less than one second from applying the target voltage, until a flow rate is detected, followed by reducing the voltage until the target flow rate is reached.

Description

METHOD AND DEVICE FOR BREWING A BEVERAGE

Technical field of the invention

The present invention relates to a method and a device for brewing a beverage. In particular, the invention relates to infused tea-based beverages that are brewed in a device having an infusion chamber from capsules. Background to the invention

Beverages such as tea and coffee are usually prepared in the home using ground coffee, tea bags or loose-leaf tea. However, the long brewing time required and the mess that is produced are inconvenient. Therefore brewing devices have been devised which provide a convenient, rapid and consumer-friendly way of brewing such beverages.

WO 2014/006051 discloses a motorized beverage machine which is designed to work with tea. The device has a large visible brew chamber. Heated water is pumped directly into a capsule containing the tea leaves, which are promptly ejected into the infusion chamber. Thus the capsule needs to be designed so that it is capable of allowing the tea leaves to exit the capsule before they have an opportunity to swell and become jammed inside the capsule. When a user instructs the machine to make a cup of tea the machine begins a complicated process involving interactions between the hardware and software. Sensors are provided to provide feedback loops to optimize the production of the cup of tea. In the initial stages, the machine is designed to produce a flow of steam from the heater directly into the capsule, as this has been found to provide effective ejection of the tea leaves from the capsule. This is typically achieved by the initial flow rate of water to the heater being low, to ensure that it is vaporized by the time it leaves the heater and enters the capsule. Such beverage machines typically contain at least one pump, e.g. for supplying water to make the beverage.

Pumps available from pump suppliers are provided with information as to their capacity when operated at maximum speed. Such pumps are usually however of a variable type and the actual speed can be altered on a scale of from 0 to 100% of maximum speed. Typically, this is achieved by altering the voltage from 0 to a maximum value commensurate with 100% speed of operation. Pump

manufacturers may even provide performance curves for such pumps to indicate the expected or target flow rates that could be expected for a given applied target voltage.

It has been found that pumps of the required capacity may need to be operated at a small fraction of their maximum capacity, e.g. 5 or 10% of maximum capacity in order to achieve this steam effect. Such pumps are typically controlled by a voltage input and thus, the voltage applied to such pumps is in the region of up to 60% of the maximum.

However it has been found that a surprising number of such pumps operating at this voltage level provide no flow at all. Furthermore, operating the pumps at a higher voltage does result in the majority of pumps providing flow, however a surprising number still provide no flow and some provide too great a degree of flow.

Such variability does seem to reduce at higher operating voltages and the consistency is very good at maximum voltage. However the unpredictability at low voltages remains a problem. Thus, applying low voltage levels to such pumps produces unexpected results. In some cases there is no flow of water at all and the heater can burn out. In other cases the flow of water is too great and water enters the capsule of tea. This can cause the tea to swell, as the flow of liquid is too low to cause ejection of the tea from the capsule. In either case the result is unsatisfactory.

Thus there is a need for improvements in this area. Brief description of the invention

The present inventors have found that an effective way to overcome the unpredictability of pumps operating at low levels is conveniently solved by means of a pump start-up controller.

Thus, in a first aspect, the invention relates to a method of starting-up a pump for providing a flow of liquid in a brewing device, the method involving applying a target voltage to the pump in order to achieve a target flow rate, the method involving employing a start-up controller adapted to apply an excess voltage, in excess of the target voltage, and in less than one second from applying the target voltage, until a flow rate is detected, followed by reducing the voltage until the target flow rate is reached.

In a second aspect the invention provides a brewing device, the device comprising; a reservoir for containing a supply of liquid; a pump; and a channel providing a flow channel from the reservoir via the pump; the device further comprising a flow sensing means, a target voltage supplied to the pump to achieve a target flow rate, and a pump start-up controller; the start-up controller being adapted to receive an input from the flow sensing means and the start-up controller being adapted to provide an excess voltage, above the target voltage applied to the pump until flow is sensed, in less than one second from the target voltage being supplied; the start- up controller being further adapted to reduce the excess voltage applied to the pump once flow is detected until the target flow rate is reached.

Thus, the start-up controller acts to provide an excess voltage on a short time-scale, in excess of that provided as the target voltage, in order to overcome any unpredictable unreliable operation of pumps operating at low voltages in a timely manner at start-up. In particular, this overcomes the problem of no flow being detected when the target voltage is applied to the pump. Typically the target voltage is less than 60% of the voltage required for 100% pump speed.

In general the purpose of the pump control system is to obtain a flow of liquid in a short timescale. Thus, the pump start-up controller typically discriminates between a no-flow condition and a flow condition. Furthermore, the pump start-up controller achieves this by applying a voltage to the pump which is in excess of that provided as a target voltage to achieve a target flow rate.

In a preferred type of beverage machine, a control system may already be present to deliver the target voltage, which is adapted to deliver heated water for making a beverage, based on measuring the flow rate and/or temperature of delivered water and adapting the pump speed and/or heater speed until a target temperature and/or volume of heated water is delivered. However such a control system is generally designed to operate over relatively long time scales (10s of seconds) and takes corrective action only relatively slowly, in order that the delivery of the hot beverage is consistent and reliable. As such, although they can also control any pumps, they may act too slowly to deal with the aforesaid problems with reliability of pumps operated at low voltage, particularly during the very initial phase of beverage preparation. Preferably the method according to the invention relates to a method of preparing a tea-based beverage in a brewing device, the device comprising: an infusion chamber; a capsule holder for receiving a capsule and being in fluid communication with the infusion chamber; a reservoir for containing a supply of water; a heater for heating and/or vaporizing water; a pump; and a channel providing a flow channel from the reservoir via the pump and heater, the channel arranged to direct water flow directly into the capsule when placed in the capsule holder; the method comprising the steps of:

a) inserting a capsule containing tea material into the capsule holder;

b) carrying out the method described above.

Preferably the brewing device, is a device comprising an infusion chamber; a capsule holder for receiving a capsule and being in fluid communication with the infusion chamber; a reservoir for containing a supply of water; a heater for heating and/or vaporizing water; a pump; and a channel providing a flow channel from the reservoir via the pump and heater, the channel arranged to direct water flow directly into the capsule when placed in the capsule holder.

It has been further noted that the problem of pump variability is even more acute when heated water or steam is directed to enter a capsule containing particulate material, particularly a swelling particulate material, which is intended to vacate the capsule. For example, tea material is known to swell when wet, and thus, introducing a large amount of water to the capsule can cause the tea leaves to swell and remain in the capsule, rather than vacate the capsule into an infusion chamber.

Thus, it has been found that control of the flow rates of water and/or steam delivery in the initial stages are even more critical when the flow is directed into a capsule containing a swellable particulate material such as tea leaves. It has been found that a brief burst of steam is very effective at ejecting tea material from a capsule, whereas water, even hot water, can simply cause the tea to swell and remain in the capsule and unable to be involved in an infusion. Thus, the pump start-up controller preferably acts to increase the excess voltage during the first 5 seconds of beverage manufacture, more preferably only the first 3 seconds.

The pumps according to the invention are required to deliver water to form a beverage in a machine. They are typically a solenoid or reciprocating pump. Additionally, their maximum capacity is preferably in the range of from 0.2 to 5 l/min, more preferably from 0.5 to 2 l/min.

It has been found that such pumps take some time to react to a change in applied voltage. This lag in response can be of the order of 400 to 500ms, and therefore can be an appreciable length of time during the important initial few seconds of operation. It has therefore been found that the increases in the voltage applied to the pump are more effectively applied in steps, rather than in a gradual increase. This is so that the impact of a step change in applied voltage can be assessed before deciding on which further action to take.

Preferably the pump start-up controller checks the flow rate once every 50 to 500ms, preferably once every 100 to 300ms. The pump start-up controller could apply excess voltage to the pump in a number of ways, e.g. by adding discrete voltage amounts to the target voltage or by a percentage increase in the target voltage applied. It has been found that a percentage increase in the voltage applied by the main control system is a convenient way to provide the excess voltage. Thus in this embodiment the excess voltage is defined as a percentage increase in the target voltage. In a preferred embodiment, the start-up controller is adapted such that when a no- flow condition is detected the start-up controller applies an excess voltage of at least 10% more than the target voltage, in a first pump voltage kick. However, the variability of available pumps is such that even with such a voltage increase it has been found that some pumps still do not present any flow on a short enough timescale.

Thus, in a preferred embodiment the start-up controller is adapted to increase the excess voltage by a further at least 10%, in a second pump voltage kick, if the no flow condition persists for from 200 to 500ms following the first pump voltage kick.

It has been found that some pumps vary in performance to such an extent that a third, fourth or even fifth such pump voltage kick is needed to deliver the excess voltage necessary to remove the no-flow condition.

Once the no-flow condition is removed and flow is detected, due to the presence of the excess voltage applied to the pump, the flow rate is then typically initially in excess of the target flow rate. However if the excess voltage is removed too quickly the no-flow condition can reappear.

Thus, preferably the pump start-up controller is configured to reduce the excess voltage is reduced after a period of from 300 to 700ms after detecting a flow which is in excess of the target flow rate.

Additionally it is preferred that the pump start-up controller is configured such that the excess voltage is reduced at a rate of 15% excess voltage being removed over at least 300ms, which may be gradual or stepwise. It has also been noted that the excess voltage can be removed faster initially, but to keep the pump going at the low target flow rates it must change the step down slowly at the low target flow rates. This is to keep the pump flowing without entering a no-flow condition, but not introduce too much water into the capsule to prevent leaves coming out when the steam starts to be delivered.

Thus, when the excess voltage is less than 10%, it can be reduced at a rate of 3% being removed over at least 30ms (300ms?)

As used herein the term "tea material" refers to tea plant material, herb plant material or a mixture thereof. For the avoidance of doubt, the term "tea material" does not include coffee material. The term "tea plant material" refers to leaf, bud and/or stem material from Camellia sinensis var. sinensis and/or Camellia sinensis var. assamica. The tea plant material may be substantially fermented (i.e. black tea), partially fermented (i.e. oolong tea) or substantially unfermented (i.e. green tea or white tea). It may also be a blend of one or more of the aforementioned tea plant materials. Other ingredients which are commonly used to flavour leaf tea products may also be combined with the tea plant material (e.g. bergamot, citrus peel and the like). The term "herb plant material" refers to material which is commonly used as a precursor for herbal infusions. Preferably the herb plant material is selected from chamomile, cinnamon, elderflower, ginger, hibiscus, jasmine, lavender, lemongrass, mint, rooibos (obtained from Aspalathus linearis), rosehip, vanilla and verbena. The tea material may additionally comprise fruit pieces (e.g. apple, blackcurrant, mango, peach, pineapple, raspberry, strawberry etc).

Preferably the tea material is dried and has a moisture content of less than 30 wt %, more preferably less than 20 wt % and most preferably from 0.1 to 10 wt %. Preferably the tea material particles have a size (i.e. longest diameter) of from about 2 to about 10mm, preferably 3 to 7mm.

The term "beverage" refers to a substantially aqueous drinkable composition which is suitable for human consumption. Preferably the beverage comprises at least 85% water by weight of the beverage, more preferably at least 90% and most preferably from 95 to 99.9%. Preferably the beverage comprises from 0.04 to 3%, more preferably from 0.06 to 2%, most preferably from 0.1 to 1 % by weight tea solids. The term "brewing" refers to the addition of a liquid, particularly hot water, to tea material, so that steeping or soaking the tea material in the liquid releases soluble substances into the liquid (e.g. flavour and/or aroma molecules) thereby to form a beverage. Brewing may be carried out at any temperature, but preferably in the range of 80 to 95°C.

The term "infusion chamber" means a vessel in which infusion of tea material takes place, and which is large enough both to allow the tea material to move around in the liquid during infusion, and also to contain a substantial part (i.e. at least 50%) of the volume of the final beverage. The term "infusion chamber" therefore does not refer to capsules inside which brewing takes place, as is typically the case in coffee machines.

The term "capsule" refers to a rigid or semi-rigid container in which tea material is or may be packaged, for example a capsule, cartridge, pod, or the like.

The present invention will now be described with reference to the figures, wherein:

Figure 1 shows a brewing device according to the invention.

Figure 2 is a schematic diagram showing the main functional components of the device.

Figure 3 shows an embodiment of the capsule holder removed from the device, and containing a capsule.

Figure 4 shows (a) a side view of a capsule, (b) a perspective view of a capsule without a lid and (c) with a lid.

Figure 5 shows the manifold of the infusion chamber with an opening member for opening the lid of the capsule. Figure 1 shows one non-limiting embodiment of a brewing device according to the invention. The device 1 has a casing 2 with a front side 3 and a rear side 4. An infusion chamber 10 and a capsule holder 20 are located at the front side of the device. The infusion chamber 10 has a bottom rim 12 which defines an opening in its lower side. The infusion chamber may have an opening in its top side which is covered with a removable lid 15, or it may be constructed as a vessel without an opening in its top side. The capsule holder 20 is designed to receive a capsule. It is located in a support 6 and preferably has a handle 22. The capsule holder is preferably substantially circular when viewed from above, which provides for easy cleaning since there are no corners in which tea leaves could become trapped.

In Figure 1 , the capsule holder 20 is shown in position for brewing, i.e. so that the upper rim 23 of the capsule holder is in water-tight contact with the bottom rim 12 of the infusion chamber 10. The infusion chamber 10 is supported and held in place by a manifold (not shown). A water reservoir, heater, and pump (not shown) are located inside the rear 4 of the casing. At the bottom of the front side 3 of the casing there is a tray 8 on which a cup 9 is placed when the beverage is dispensed. A dispensing spout 7 is positioned beneath the capsule holder.

Figure 2 is a schematic diagram showing the main functional components of the device. Water from the reservoir 50 is fed to the infusion chamber 10 via a water filter 52, a water pump 54 (Defond Solenoid pump (PF60A) which is a 27W pump), flowmeter 53, a heater 56 and a valve 57. The heater is preferably a flow-through heater. The valve 57 controls the route the water takes between the heater 56 and the infusion chamber 10. For example, the water may firstly be pumped to the infusion chamber 10 via the capsule 30 in order to brew a beverage 60. Subsequently, the valve 57 can re-direct the water such that it enters the brewing chamber 10 via a rinse head 18 in order to rinse and/or clean the brewing chamber 10. There may also be an air pump 58 which can pump air to the infusion chamber, for example via the capsule 30 which is located in the capsule holder 20, or via the capsule holder itself. The spout 7, cup 9 and tray 8 are located beneath the capsule holder 20. A pump start-up controller 51 is also provided which is configured to read the flowmeter and provide an input into the pump 54. The flow meter 53 updates its flow rate every 100ms, and the current flow rate is the last 1 s of flow. Every 200ms the flow rate is checked and if the flow rate is 0%, the target voltage is increased by 15% by the start-up controller 51 . The no-flow kick will then not increase the rate again for at least 400ms, to give the pump time to cause the flow rate to increase.

If after this time the flow rate is still zero, the start-up controller 51 increases the excess voltage in steps of 15% every 400ms. It is however capped at 100%.

The no flow kick must then wait a minimum of 500ms before it is allowed to decrease the additional kick once flow has been detected. This prevents the flow dropping back to 0% suddenly and repeating the problem of zero flow.

The start-up controller 51 decreases the excess voltage by 15% each 500ms until it is less than 10%, where it steps down every 40ms in steps of 3% until less than 3%, where it returns to 0. This is because the initial large steps get the pump flowing and can be removed almost immediately once flow is achieved, but to keep the pump going at the low rates it changes the step down slowly at the low rates to keep the pump flowing, but not introduce too much water into the capsule to prevent leaves coming out when the steam starts to be delivered. Figure 3 shows perspective views of an embodiment of the capsule holder 20 which consists of two separable parts, a receptacle 70 and a strainer 72. Figure 3(a) shows the capsule holder when assembled with a capsule 30 in place, and Figure 3(b) shows the capsule, strainer and receptacle separated. The receptacle 70 has a sidewall 24 and a base 26. Again, the sidewall is preferably circular when viewed from above. Located in the base 26 is a passage 29 through which the beverage flows during dispensing and which is closed by a drain valve (not shown) during brewing. The receptacle 70 has a handle 22.

The strainer 72 has a base 73, a rim 74 and a handle 75. One or more protrusions 78, such as a shelf on the inside of the rim 74, support the capsule 30 and hold it in place above the base. At least part of the base 73 is made up of a filter 25. In the preferred embodiment shown, the part of the base 73 which is located underneath the capsule is solid whilst the rest of the base consists of the filter. The solid part may also serve to support the capsule. The filter preferably consists of a fine mesh made, for example, of stainless steel, nylon, polyester or PTFE. The mesh size must be sufficiently small to catch small pieces of tea material but large enough to ensure that draining is not too slow. Preferably, the mesh size is from 100 to 500 microns, more preferably 150 to 300 microns. As shown in Figure 3(a), in use the strainer 72 rests on the receptacle and is supported by the sidewall 24. The rim 74 of the strainer forms the upper rim 23 of the capsule holder 20. The strainer covers the whole of the top of the receptacle 70, so that liquid cannot pass between the rim 74 of the strainer and the sidewall 24 of the receptacle, and hence can only enter the receptacle 70 by passing through the filter. The filter prevents spent tea leaves from entering the receptacle 70. Preferably the rim 74 is made from an elastomeric material. Thereby it is in effect a gasket which forms seals both between the receptacle and the strainer, and also between the capsule holder and the infusion chamber. This embodiment has the advantage that the strainer and receptacle can be easily separated for cleaning. Moreover, in order to empty out spent tea leaves from the capsule holder, it is only necessary to remove the strainer and tip the spent leaves out from it. Figure 4(a) shows a side view of a capsule 30. The capsule comprises a body part 31 and a lid 32. The body part 31 defines a cavity 35 in which the tea material 36 is placed. The lid is attached to the body part so as to enclose the tea material 36 within the capsule. The functionality required of the capsule is significantly reduced compared to known capsules, because the capsule does not contain a filter. The brewing liquid does not need to enter through one side and exit through the other, so there is no need to puncture or otherwise make an opening in the body part of the capsule. Thus the construction of the capsule is greatly simplified. Thus the body part is a single, impermeable piece and does not contain any means (for example a filter, or an openable or weakened area) for allowing liquid to enter or exit the capsule through the body part. The body part is preferably made from plastic or aluminium. It may be formed for example by injection moulding or by thermoforming.

The cavity 35 is preferably generally circular in cross-section, when viewed from above, as shown in Figure 4(b). This shape is convenient from the point of view of manufacture and also for filling tea material into the capsule. It also facilitates release of the tea material from the capsule during brewing, since there are no corners or other areas where the tea material could become trapped. "Generally circular" does not require that the cavity has an exactly circular cross-section; thus for example it could have small indents, provided that there are no narrow recesses in which tea material could become trapped.

The body part preferably comprises a flange 33, and the lid is preferably attached to the flange, e.g. by heat-sealing, thereby enclosing the tea material. In order to provide sufficient area to attach the lid securely, the flange is preferably at least 3mm wide. The flange 33 preferably also serves to support the capsule in the capsule holder by resting on the protrusions on the inside the capsule holder, described above. Thus the flange is preferably shaped and sized to match its intended location in the capsule holder. Since the capsule only needs to be large enough to contain a single serving of the dry tea material it can be much smaller than known capsules. Thus the internal volume of the capsule (i.e. the volume of the cavity) is from 10 to 24cm³, preferably 12 to 19cm³, most preferably from 14 to 18cm³. Moreover, the capsule only needs to be strong enough to support dry tea material, and not wet spent tea material. Thus the body part of the capsule can also have relatively thin walls.

The reduced capsule size means that the amount of material (e.g. plastic) needed to make the capsule is significantly reduced. This has environmental and cost advantages. Furthermore, the capsule body part can be more easily recycled because it is made of a single material, unlike typical capsules having a filter. A small capsule also has the advantage of taking up less space during transport and during storage, for example in a consumer's cupboard.

The cavity must not be so shallow that tea material bounces out of it during filling. Thus the depth of the cavity is preferably at least 10mm, more preferably at least 13mm. On the other hand, the cavity must not be so deep that it is difficult to remove the tea material from the capsule at the start of brewing. Thus the depth of the cavity is preferably at most 20mm, more preferably at most 18mm. It is easier to remove the tea material from a cavity with a depth in the upper part of this range when the volume of the cavity is also towards the upper end of its range (i.e. when the cavity is not both deep and narrow).

The cross-sectional area and diameter of the cavity are related to the required volume and depth. Consequently, the diameter of the cavity is preferably from 30 to 45mm. The lid, which overlaps with or covers the flange as well as covering the cavity, is therefore preferably from about 45 to 60mm in diameter, more preferably 47 to 58 mm. The lid is preferably shaped to generally match the shape of the flange.

The lid is preferably made of a thin film, more preferably metallic foil or a laminated foil, most preferably a laminate of aluminium foil and polyethylene. Preferably the lid has perforations in order to facilitate opening the capsule to inject water and release the tea material, as will be described below. More preferably the lid 32 has a line of perforations 34 in the form of a curve, with sections which extend backwards from the ends of the curve, as shown in Figure 4(c).This configuration produces a well-defined opening when the lid is pushed against a blunt opening member (described below), which allows the tea leaves to be released from the capsule. The cu tie ratio of the perforations should be such that they do not burst too easily, for example during transport, but nonetheless open without requiring too great a force. For example, for an aluminium foil / polyethylene laminate lid, a cu tie ratio of around 1 :2 is suitable.

Typically the capsules are provided to the consumer in air-tight secondary packaging, for example as multipacks containing a plurality of capsules (e.g. ten). The multipacks may contain packages of a single type, or a mixture of packages containing different types of tea (e.g. green tea, black tea, herbal tea). Having a perforated lid has a further advantage in that some of the tea aroma is released from the tea material inside the capsule into the space inside the secondary packaging. Thus the consumer obtains the aroma of tea on opening the secondary pack. In a preferred embodiment, the cavity has a generally circular cross-section, but the flange is elongated, for example it is generally elliptical in shape, or is defined by two intersecting circular arcs. "Generally elliptical" does not require that the flange is exactly elliptical. The flange has a radius of curvature that is similar to the radius of the inside of the sidewall 24 of the capsule holder, so that the shape of the flange generally corresponds to the shelf. Nonetheless, small variations from an elliptical shape can be accommodated whilst there is still sufficient overlap between the flange and the shelf to support the capsule.

This shape of flange allows the capsule to be supported by the shelf 78 on the inside of the sidewall of the capsule holder. This avoids the need for supporting ribs or protrusions inside the capsule holder, which could trap tea leaves, and hinder cleaning. The ratio of the longest diameter of the flange to the shortest diameter of the flange is preferably from 1 .2:1 to 1 .5:1 . A minimum ratio of 1 .2:1 gives plenty of space for the brewed beverage to pass by the capsule, and a maximum ratio of 1 .5:1 means that the capsule can be large enough to contain sufficient tea material, without requiring an excessively large capsule holder.

In this embodiment, the shape of the lid is preferably also defined by two intersecting circular arcs, but with truncated ends 38, as shown in Figure 4(c). The length of the lid between the two truncated ends is from 47 to 58mm, and the maximum width of the lid is from 45 to 50 mm. The capsule is symmetrical (in particular it has 180° rotational symmetry about a vertical axis). There are preferably two sets of perforations in the lid, arranged symmetrically, as shown in Figure 4(c), so that the capsule can be placed in the capsule holder in either of two orientations. In a preferred embodiment, the body part of the capsule is transparent, so that the tea material inside the capsule is visible. This is attractive to the consumer, and also has the advantage that the contents can be inspected for quality control purposes after filling using optical means, rather than, for example, by weight. In use, the device functions as follows. With the capsule holder in its lowered position, the user may just remove the strainer from the receptacle. A capsule containing tea material is placed into the capsule holder so that it rests on the protrusions on the inside of the sidewall and / or the base of the capsule holder. The protrusions support the capsule and preferably also locate it in the correct position.

The capsule holder is then replaced on the support. Next, the user raises the support, for example by pressing a button on the device which activates an actuator. The capsule holder travels vertically upwards until it connects with the infusion chamber, and forms a water-tight seal. In an alternative embodiment, the infusion chamber could move down towards the capsule holder. The capsule holder and infusion chamber may be connected by means of an intermediate member such as a gasket (for example a ring made of rubber or other compliant material located on the upper rim of the capsule holder and / or the bottom rim of the infusion chamber) in order to provide a good seal. The infusion chamber and the capsule holder form a space for brewing when connected. Preferably the volume of the space for brewing is at least 75%, more preferably at least 90% of the volume of the final beverage. The device may have means for recognizing a capsule and / or reading information from a code associated with the capsule or the capsule holder. Different codes may be associated with different types of tea (e.g. green tea, black tea, herbal tea etc.). This allows the capsule to be recognized by the device, so that the device can automatically set the parameters for the brewing operation, such as the brewing time, water temperature etc.. It also allows the device to be programmed so that it only operates if the correct type of capsule is present. Thus a valid code signifies that an expected type of capsule is present, and an invalid code signifies an unexpected type of capsule, a capsule that has already been used or that no capsule is present. The recognition system can be of any suitable type, such as mechanical interlocking between the capsule and the capsule holder; optical recognition (e.g. by means of colour, fluorescence or bar code), electrical, magnetic, radio-frequency identification (RFID) chip etc..

Optionally, the device may also have means for allowing the user to adjust the parameters of the brewing operation, such as the brewing time, the receptacle size etc. The means may suitably consist of buttons or other inputs on the device, together with a control system.

The lid of the capsule needs to be opened or removed in order to release the tea material. Preferably the lid is opened automatically by the device after the capsule has been inserted into the capsule holder, e.g. as the upper rim of the capsule holder is connected to the bottom rim of the infusion chamber. Preferably, two openings are made in the lid, one to introduce liquid into the capsule and the other to release liquid and tea material into the infusion chamber. However, because the capsule does not have a filter, there is no need to puncture or otherwise make an opening in the base of the capsule.

In a preferred embodiment, shown in Figure 5, the lid is opened by pushing it against one or more static opening members when the capsule holder travels upwards to connect with the bottom rim of the infusion chamber. The lid 32 is pushed against a static opening member 40 located on the infusion chamber manifold 16. The function of the member is to create an opening in the lid in order to release liquid and tea material. This can be achieved by a member with a sharp edge which cuts or punctures the lid. Alternatively, the lid may have pre-formed weaknesses, such as perforations 34 which reduce the force required to open it. In this case, the member 40 can be blunt, for example a wire. Preferably the member is angled or has a sloped part 41 so that as it moves into the capsule, the flap formed by opening the lid is pushed away from the opening and held out of the way whilst the tea material is released from the capsule. In the preferred embodiment shown in Figure 5, a second opening for introducing water and/or steam into the capsule is made by pushing the lid against a static needle 42 consisting of a tube with a pointed end. The needle 42 pierces the lid. Water or steam is then pumped from the reservoir to the heater, which is preferably a flow-though heater. The resulting hot water and/or steam is then pumped to the capsule and enters it through the needle. The influx of hot water pushes the tea material out from the capsule through the opening made by the opening member 40 and into the infusion chamber 10.

The heater and pump are controlled (separately to the pump start-up controller) so that the target brew temperature (which is typically in the range 80°C to 95°C) is achieved in the infusion chamber. Typically the water flow rate is in the range of 200 to 400ml/nnin, and the volume of water is 150 to 300ml, depending on the desired size of the beverage.

Once brewing has taken place for the required time, the drain valve 21 located in the base of the capsule holder 20 is opened, allowing the beverage to drain from the infusion chamber. Preferably the opening of the drain valve is controlled automatically by the machine. The beverage flows from the infusion chamber through the filter 25 located in the capsule holder below the capsule, through the passage 29, and finally into a cup 9 which the user has already placed onto the tray 8. Tea material is prevented from entering the cup 9 by the filter 25.

Finally, after the beverage has been dispensed, the capsule holder is lowered, preferably automatically, or alternatively by the user, for example by activating a button. The user then may just remove the strainer from the receptacle. The used capsule and spent tea leaves are then disposed of, and the capsule holder can be rinsed. Since the capsule holder is removable from the brewing device, it is easy to clean. The capsule holder is then returned to the support, ready for the next use.

The various features of the embodiments of the present invention referred to in individual sections above apply, as appropriate, to other sections mutatis mutandis. Consequently features specified in one section may be combined with features specified in other sections as appropriate. Various modifications of the described modes for carrying out the invention which are apparent to those skilled in the relevant fields are intended to be within the scope of the following claims.

Examples

A number of pumps suitable for use in a beverage machine as described herein were tested for their response to applying a voltage.

Pumps tested Defond™: Model: 60 Type: PF60A 230V 50 Hz 27W (PF60A-230A-AAD-02)

• (10 samples numbered 130353#1 , 4, 5, 7-13)

Ulka™ HF 230V 50Hz 22W

· (labelled #4, 12, 13, 215, 333, 394)

Ulka™ HF/S 230V 50Hz 27W

• (labelled #2)

Test method

Position pump with anti-vibration mounts on a flat surface. A Variac™ AC controller is connected to the pump to provide a range of voltages.

• Connect pipes (5mm bore, ~ 400mm long) to each end of the pump, the open ends into a suitable water reservoir (beaker) containing water at room temperature at a similar level to the pump

• Ensure the variac is switched off, connect mains power wires from the variac to the pump under test (live to the diode symbol on the pump).

• Set the variac to 230Vac (use a multimeter to measure the variac output voltage), switch on the variac output briefly to purge the pipes of air.

• Place the outlet pipe into an empty container. Run the pump and measure the amount of water pumped (calculate the mL/minute value if the pump is not run for 1 minute).

• Adjust the variac and repeat. Test at 230, 200, 190, 180, 170, 160, 150, 140, 130, 120 and 1 1 OVac.

• Ensure there is a delay of at least 1 minute between tests.

• Ensure the variac is off before disconnecting any wires.

Results for pump Defond™ PF60A Table 1 : water flow rates as a function of applied voltage to a number of Defond PF60A pumps

As can be seen, at 230 volts, the pumps varied in flow rate from 795 to 909 ml/min, with a mean of 861 with a variation of +/- 7%.

However, at 1 10 volts, the pumps varied from 38 to 80 ml/min, with a mean of 58 ml/min with a variation of +/- 35%.

Results for pump Ulka™ HF, Ulka™ HF/S

Table 2: water flow rates as a function of applied voltage to a number of Ulka

HF pumps and one Ulka™ HF/S pump Ulka Ulka HF Ulka HF Ulka HF Ulka HF Ulka HF Ulka HF Ulka HF Ulka HF Ulka HF HF/S #2 #12 #13 #4 #215 #333 #394 Min Ave Max

Voltage ml/min ml/min ml/min ml/min ml/min ml/min ml/min ml/min ml/min ml/min

110

120 36 35

130 78 31 60 46 50 35 31 44 60

140 131 71 106 42 84 95 63 42 77 106

150 196 120 145 74 140 145 115 74 123 145

160 294 178 214 146 204 225 192 146 193 225

170 400 256 291 222 290 318 280 222 276 318

180 528 352 398 322 406 414 390 322 380 414

190 606 462 500 422 531 525 480 422 487 531

200 678 540 570 549 591 588 573 540 569 591

230 873 759 795 750 810 810 849 750 796 849

As can be seen, at 230 volts, the pumps varied in flow rate from 750 to 849 ml/min, with a mean of 796 with a variation of +/- 6%.

However, at 120 volts only one out of six Ulka HF pumps produced any flow at all. At 130 volts five out of six produced flow but one remained providing no flow at all. Furthermore, the highest flow rate at 130 volts was 60 ml/min, giving a variation of from 0 to 60 ml/min, which gives a variation of 100% from a mid value of 30 ml/min.

Claims

1 . A method of starting-up a pump for providing a flow of liquid in a brewing device, the method involving applying a target voltage to the pump in order to achieve a target flow rate, the method involving employing a start-up controller adapted to apply an excess voltage, in excess of the target voltage, and in less than one second from applying the target voltage, until a flow rate is detected, followed by reducing the voltage until the target flow rate is reached.

2. A brewing device, the device comprising; a reservoir for containing a supply of liquid; a pump; and a channel providing a flow channel from the reservoir via the pump; the device further comprising a flow sensing means, a target voltage supplied to the pump to achieve a target flow rate, and a pump startup controller; the start-up controller being adapted to receive an input from the flow sensing means and the start-up controller being adapted to provide an excess voltage, above the target voltage applied to the pump until flow is sensed, in less than one second from the target voltage being supplied; the start-up controller being further adapted to reduce the excess voltage applied to the pump once flow is detected until the target flow rate is reached.

3. A method or brewing device as claimed in claim 1 or claim 2, wherein the target voltage is less than 60% of the voltage required for 100% pump speed.

4. A method or brewing device as claimed in any one of the preceding claims, wherein no flow is detected when the target voltage is applied to the pump.

5. A method or brewing device as claimed in any one of the preceding claims, wherein a main control loop is provided, which delivers the target voltage to the pump, and is adapted to deliver heated water for making a beverage, based on measuring the flow rate and/or temperature of delivered water and adapting the pump speed and/or heater speed until a target temperature and/or volume of heated water is delivered.

6. A method or brewing device according to any preceding claim, wherein the start-up controller is a closed loop feedback controller.

7. A method or device according to any one of the preceding claims, wherein the liquid consists essentially of water.

8. A method or device according to claim 7, wherein the water is pumped through a water heater arranged to heat the water to steam and/or hot water.

9. A method or device according to claim 8, wherein the steam and/or heated water is directed into a capsule comprising swellable particulate material, preferably tea material.

10. A method or device according to any one of the preceding claims, wherein the excess voltage is provided in one or more steps.

1 1 . A method or device according to any one of the preceding claims, wherein the start-up controller is adapted such that when a no-flow condition is detected the start-up controller applies an excess voltage of at least 10% more than the target voltage, in a first pump voltage kick.

12. A method or device according to claim 1 1 , wherein the start-up controller is adapted to increase the excess voltage by a further at least 10%, in a second pump voltage kick, if the no flow condition persists for from 200 to 500ms following the first pump voltage kick.

13. A method or device according to any one of the preceding claims, wherein the start-up controller is adapted to begin reducing the excess voltage after a period of from 300 to 700ms after detecting a flow condition.

14. A method or device according to any one of the preceding claims, wherein the start-up controller is adapted to reduce the excess voltage at a rate of 15% excess voltage being removed over at least 300ms after detecting a flow condition.

15. A method or device according to any one of the preceding claims, wherein the start-up controller is adapted to reduce the excess voltage at a rate of 3% being removed over at least 30ms, when the excess voltage is less than 10%.

16. A method of preparing a tea-based beverage in a brewing device, the device comprising: an infusion chamber; a capsule holder for receiving a capsule and being in fluid communication with the infusion chamber; a reservoir for containing a supply of water; a heater for heating and/or vaporizing water; a pump; and a channel providing a flow channel from the reservoir via the pump and heater, the channel arranged to direct water flow directly into the capsule when placed in the capsule holder; the method comprising the steps of a) inserting a capsule containing tea material into the capsule holder;

b) carrying out the method according to any one of claims 1 and 3 to 14.

17. A brewing device according to any one of claims 2 to 15, comprising an infusion chamber; a capsule holder for receiving a capsule and being in fluid communication with the infusion chamber; a reservoir for containing a supply of water; a heater for heating and/or vaporizing water; a pump; and a channel providing a flow channel from the reservoir via the pump and heater, the channel arranged to direct water flow directly into the capsule when placed in the capsule holder.