WO2011110871A2

WO2011110871A2 - Electrical apparatus

Info

Publication number: WO2011110871A2
Application number: PCT/GB2011/050493
Authority: WO
Inventors: Rene Shum; Gary Lane
Original assignee: Green Lane Products Limited
Priority date: 2010-03-12
Filing date: 2011-03-14
Publication date: 2011-09-15
Also published as: GB201216956D0; WO2011110871A3; GB201004135D0; GB2491318A

Abstract

Apparatus for electrically heating a food product comprises an container (10) for the food product and a void (25) containing an electrical heater (30). The container is upwardly open to introduce / remove the food product. The void is enclosed but has, in its base wall, a valve (35) which allows air to vent from the void but prevents water from entering the void.

Description

Electrical Apparatus

This invention relates to an electrical apparatus for culinary use.

The reader will be familiar with a design of electric kettle in which an electric lead is connected directly to the kettle housing; and with later designs of kettle in which there is a jug part which is located on an electrical base unit, the base unit being permanently connected to the electric lead.

The latter type of design in which a container may be coupled to or de-coupled from an electrical base unit has been proposed for use in heating other types of foodstuffs, for example milk. Further, it has been proposed for use with apparatus which is arranged to perform an operation on the contents of the container, through the agency of a motor contained within the base unit. In the case of milk, the motor in the base unit may drive a whisk within the container, so that the apparatus both heats and froths the milk. It will be appreciated that in such apparatus there is a need to couple and decouple the whisk from the motor, and there may be a driving arrangement between them. For example there may be a gear arrangement with a first driving gear at the upper exposed face of the base and a second driven gear at the lower exposed face of the container. It is difficult to realise a design which requires consumers to couple and uncouple exposed gears in a reliable manner, and there are manufacturing difficulties also.

It will be appreciated that the container needs to be cleaned after use and to achieve this it is removed from the base unit and washed-up by hand, or in a machine dishwasher if that is recommended. When dried it is put back on the base unit and it is to be hoped that the gear units are correctly meshed, ready for use.

Furthermore a base unit could contain heater means to heat contents within the container.

Furthermore a base unit could contain an electronic control means, for example a printed circuit board (PCB) or central processing unit (CPU), if a certain level of control over the process of heating food products within the container is required.

In considering the prior art we have formed the view that it would be desirable to produce an apparatus in which an electrical means - which may include at least a heater means - are provided, with the container, as a single unit which can be disconnected from an electric lead or base init and washed, for example immersed, as in the case of a manual dishwashing method, or subjected to the demanding environment of a dishwashing machine. We have experimented with an apparatus which has an upper chamber for a food product, and a separate sub-chamber or void which contains a heater means to heat a food product in the container. There is a rod which extends from the motor in a base unit, and the rod passes through a wall of the housing, which separates the container from the sub-chamber, to a whisk within the container. A seal is provided around the rod to prevent passage of a liquid food product from the container to the under-chamber, and other, external, seals are provided where parts are joined together, for example a base connecting plate to side walls. We found that when such a unit was washed in a domestic machine dishwasher the seals around the rod or around the base of the housing were breached, and water leaked into the under-chamber. This is believed to be the result of significant pressure changes within the under-chamber. It is assumed that air pressure within the under-chamber at the start of the washing operation is atmospheric pressure, and as the temperature rises, perhaps to 60°C or even 80°C, there is a significant increase in the air pressure, within the container, to the extent that air exits the under-chamber, by breaching one of more of the aforesaid seals. In the course of the breach the seals are damaged so that, when the dishwasher cools and the air pressure within the under-chamber substantially reduces, the seals are once again breached, but in the opposite direction, with air and water entering the under-chamber.

The presence of water inside the under-chamber at the end of a dishwashing operation is, obviously, completely unacceptable.

However we have persisted, and have devised an improved apparatus which overcomes the problem just referred to.

In accordance with a first aspect of the present invention there is provided apparatus for electrically heating a food product, the apparatus comprising a housing with a container for the food product and an void adjacent to the container, the void containing electrical means, the container being upwardly open or upwardly openable to introduce the food product into it and to remove it therefrom, the void being enclosed but having, in an external wall, a device which allows air to vent from the void but prevents water from entering the void.

Preferably the device is a one-way valve, which can allow air to pass in one direction (from the under-chamber to the external environment) but prevents air, and water, from passing from the external environment into the under-chamber.

Preferably the effects described are achieved at temperatures between 0°C and 100°C; preferably between ambient temperature , which we may for present purposes regard as 20°C, up to the highest temperature to be encountered in a domestic dishwashing device, which we believe to be 80°C. Preferably, therefore, the apparatus of the present invention is "dishwasher-proof". Preferably, also the apparatus could be washed without detriment in manual washing up method.

Preferably the apparatus has a manipulator within the container, for altering the food product. The manipulator may, for example, be cutters or blades in the case of a blender, or it may be a whisk in the case of a milk frother. A rod or axle may pass from a driving mechanism to the manipulator, passing through a connecting wall between the container and the void, with a seal being located around the rod. We have found that, in our dishwashing experiments, this seal is not breached, as it was in our earlier experiment, because, we believe, of the presence of the device. Nor are other seals formed by joining parts to construct the housing, having the container and the void.

We use the words froth / frothed / frothing in this specification but the words foam / foamed / foaming can be substituted therefor.

A "whisk" in this specification means a device which can introduce sufficient air into milk to change the physical form of the milk. The term "whisk" does not imply any other limitation, for example a limitation to any particular physical construction.

We use the word "milk" in this specification to denote pure milk and also milk-based liquids, preferably having a major weight proportion of pure milk.

In most geometries it is correct to call the container, an upper container, and the void, a sub- chamber. However the sub-chamber may in many cases extend around the sides of the container, which may have a "suspended" geometry within the housing.

According to preferred embodiments of the invention the apparatus is milk frothing apparatus which comprises a container for receiving the milk to be frothed, wherein the container contains a whisk. Preferably the whisk is mounted for rotation at the bottom region of the container. Preferably the container comprises a side wall and an inclined side wall portion, wherein the inclined side wall portion is inclined with respect to the side wall. Preferably the side wall and/or the whisk are asymmetrically located within the container.

Preferably the container is partly defined by a bottom wall portion and the inclined side wall portion is confined by the side wall and the bottom wall portion; suitably with the void on the other side of such wall portions.

Thus, in such embodiments although the whisk may cause the milk or liquid in the container, the asymmetrical arrangement of the whisk and / or the container geometry may keep the maximum level of the milk or liquid low. Further, a sufficient mixing and distribution of the milk will take place so that every portion of the milk will pass the whisk. In particular by providing the inclined side wall portion, this wall portion will compensate the level increasing effect of the rotation by the whisk, as well as the oscillation of the milk level. The inclined side wall portion together with the side wall and the bottom portion provides for a surface which is easy to clean, since no further obstacles are necessary for suppressing the oscillation of the milk within the container.

It should be noted that an inclined side wall portion is inclined with respect to a vertical side wall and a horizontal plane as well, so that the inclined wall portion may be in form of a slope or ramp. It should also be noted, that the inclined wall portion can as an alternative also be provided between a lower side wall and an upper side wall, as well as the inclined wall portion can also constitute a fully inclined bottom, wherein a bottom portion then constitutes the lowest portion in the container.

In such embodiments of the invention the whisk is preferably positioned in alignment with the inclined side wall portion (horizontal alignment, when the apparatus is in its use orientation).

The whisk may be driven by a driving mechanism at least partly outside the container, for example by a motor, suitably connected to the whisk by a rod or axle; or by or a magnetic drive inducer, the whisk being associated with a magnetic follower.

In such embodiments of the invention the whisk may be provided at the distal end of a rod, wherein the container comprises a wall having a duct, wherein the rod extends through the duct so that the whisk is provided within the container, and a motor is provided on the other side of the wall. Preferably the wall is a bottom wall of the container. Thus, the whisk can be driven by the rod (which functions as an axle).

Depending on the arrangement, there may be a rod with the motor at one end and the whisk at the other (direct motor drive); or the rod may be interrupted by gears (provided to raise or lower the speed of the whisk relative to the speed of the motor, and / or to allow the whisk, in the container, to be detached from the motor, in a base part, for example for pouring frothed milk, or cleaning).

Alternatively there may be a magnetic drive mechanism wherein the whisk is carried by or associated with a magnetic follower, driven by a magnetic drive inducer. The magnetic follower may be outside the container and connected to the whisk by a rod passing through a said duct. Preferably however a magnetic follower is located inside the container and so no said duct is present in the container wall. The milk may be pre-warmed or may be warmed in-situ, as frothing takes place.

Suitably the apparatus comprises a housing which includes the said container, and further includes a heating element. Preferably the heating element is attached to at least a wall of the container; preferably to the obverse face of the wall to the milk-receiving container volume. It may thus be located, as a powered electrical means, inside the void.

Thus, the heating of the milk within the container can take place at the same time as the frothing process, so that both the heating and the frothing can take place in parallel in order to improve efficiency.

According to such embodiments of the invention, the inclined wall portion is provided off- centre. The off-centre location of the inclined wall portion serves for an improved asymmetric geometry, which reduces the oscillation of the milk or liquid in the container.

The inclined wall portion is preferably flat.

Suitably the container and the void have a shared wall.

The wall portion may have an inclination of about 45° ± (plus/minus) 15° with respect to a virtual horizontal plane during normal operation. Thus, oscillation of the rotating milk can be significantly reduced. The size of the inclined surface may be for example 50 % of the size of a surface of the bottom portion of the container. In other words, the amount of the surface of the bottom portion and the amount of a surface of the inclined wall surface may be in a similar dimension or may deviated from each other of up to about 20%. In particular, the amount of the inclined wall surface may be somewhat larger than the amount of the horizontal bottom surface.

According to such embodiments of the invention, the whisk is provided off-centre of the container.

Preferably the container comprises a filling volume of at least 75 ml, preferably at least 100 ml. Embodiments could have a filling volume of at least 185 ml.

Preferably the container comprises a filling volume of not greater than 400 ml, preferably not greater than 200 ml, preferably not greater than 150 ml.

The container may have markings to show the maximum and minimum quantities of milk to be added to the container. Due to the expanded volume of the milk froth the container requires an absolute volume considerably in excess of the volume of milk that may be added to it.

Preferably the container comprises an absolute volume of at least 220 ml, preferably at least 500 ml.

Preferably the container comprises an absolute volume of not greater than 750 ml, preferably not greater than 500 ml.

Thus, frothed milk can be prepared for a plurality of beverages simultaneously. It should be noted that the filling volume of the container is defined as the volume of milk which can be received without slopping during normal operation of the milk frothing apparatus. In other words, the filling volume may also be increased by only keeping low the liquid level in normal use. The absolute volume is the total volume of the container i.e. the maximum volume of liquid which the container can hold.

In all "container" and in all preferred embodiments of the invention the rod which carries the whisk is preferably an axle driven by the motor, so as to impart rotational movement of the whisk.

In all preferred embodiments of the invention the whisk is preferably of a filamentary form, preferably a metallic or plastics filamentary form sufficiently robust to withstand repeated whisking operations in warm milk. A preferred form of whisk is a toroidal body provided by taking a helix, bending it, and holding it in a toroidal shape, for example by joining it, end-to- end and/or using a retaining ring. Preferably such a whisk is mounted to the rod or axle centrally and perpendicularly so as to co-rotate with the rod, without giving rise to torsional forces or imbalance.

In all embodiments of the invention the whisk preferably has an overall plan area (footprint) not exceeding 20 cm², preferably not exceeding 10 cm². Preferably it is between 3 and 8 cm².

In all embodiments of the invention the whisk is preferably removable, either with or without the rod, for separate cleaning, if ever needed.

The said device could be a device allowing flow of air into and out of the under-chamber but preventing passage of water in either direction; for example a breather valve of a material such as GORE-TEX (RTM). Preferably however the device is a one-way valve. A suitable one-way valve may easily be chosen by the skilled person. The invention resides in the realisation that a one-way valve - of whatever type - may be used to allow electrical apparatus for culinary use to be washed in harsh environment, such as a dishwashing machine; rather than in the identification of suitable types of one-way valve.

However suitable types of one way valves include the following: a diaphragm check valve: a one-way valve in which a flexible rubber diaphragm is positioned to create a normally-closed valve. Pressure on the upstream side must be greater than the pressure on the downstream side by a certain amount, known as the pressure differential, for the check valve to open allowing flow; a ball check valve: a one-way valve in which the closing member, the movable part to block the flow, is a spherical ball, spring-loaded to help keep it shut, until the spring force is overcome; a stop-check valve: a one-way valve with override control to stop flow regardless of flow direction or pressure; a swing check valve or tilting disc check valve: a one-way valve in which the disc, the movable part to block the flow, swings on a hinge, either onto the seat to block reverse flow or off the seat to allow forward flow; a duckbill valve: a one-way valve in which flow proceeds through a soft tube that protrudes into the downstream side. Back-pressure collapses this tube, cutting off flow; a lift-check valve: a one-way valve in which the disc, sometimes called a lift, can be lifted up off its seat by higher pressure of inlet or upstream fluid to allow flow to the outlet or downstream side.

Preferably the whisking process herein does not involve the delivery of steam to the milk.

According to an exemplary embodiment of the invention, the milk frothing device further comprises a separate base unit for receiving the housing, wherein the base unit is provided with driving means, preferably a motor, and if present in the apparatus a CPU and/or PCB, wherein the motor and the container (more specifically, the whisk) are provided with respective mechanical coupling elements, which are adapted to be drivingly coupled together when the base unit receives the housing.

In accordance with a second aspect there is provided a method of heating a food product using apparatus in accordance with invention, as defined above. In accordance with a third aspect there is provided a method of cleaning apparatus in accordance with invention, as defined above, after it has been used to heat a food product, wherein the method entails machine dishwashing.

In accordance with a fourth aspect there is provided a method of frothing milk using an apparatus with a whisk, the apparatus being in accordance with invention, as defined above.

The invention will not be described with reference to the accompanying drawings, in which:

Fig. 1 illustrates milk frothing apparatus according to an exemplary embodiment of the invention having a housing and a base unit, wherein the base unit received the housing of the milk frothing device.

Fig. 2 illustrates a milk frothing device according to the embodiment of Fig. 1 , wherein the housing portion is released from the base unit of the milk frothing device.

Fig. 3 is a cross-sectional view of the embodiment of Fig. 1 .

Fig. 1 illustrates a milk frothing apparatus 1 with a housing portion 2 resting on a base unit 3. The housing portion 2 can be released from the base unit 3. The housing portion comprises a handle 4, which may provide for an easier handling of the housing portion of the milk frothing apparatus 1 . In order to maintain the heat within a container of the milk frothing device, the milk frothing device 1 can be provided with a cover 16. The cover may be provided as a transparent cover in order to allow a user to visually monitor the frothing process within the container of the milk frothing apparatus.

The frothing process may be started with an operation button 42, which may be provided at the base unit 3 of the milk frothing apparatus 1. When pushing the operating button, the heating process will be started e.g. synchronously to a frothing process within the container.

Fig. 2 shows the milk frothing apparatus in a released situation, where the housing portion 2 of the milk frothing apparatus 1 is released from a base unit. When releasing the housing portion 2 from the base unit 3, a contact 31 on the housing portion side can be released from a contact 41 on the base unit side. When providing the plug/socket 31/41 at the edge of the housing portion 2 and the edge of the base unit 3, respectively, a user can easily monitor when putting the housing portion 2 onto the base unit and to receive the correct positioning thereof. It should be noted that the plug/socket 31/41 can also be provided as a separate unit and that a separate forming of the edge of the base unit corresponding to the edge of the housing portion may be provided for providing an easier fit of housing 2 and the base unit 3. When releasing the housing portion 2 from the base unit 3, a frothing process and a heating process may be stopped automatically. Electronic elements in the base unit may detect the releasing of the housing portion, in order to interrupt the circuit to provide the heater with electrical current. A base unit may be provided with a connector plug to the grid, which, however, is not illustrated in the Figures.

The housing portion 2 may be released from the base unit 3 in order to provide easier handling of the housing portion during serving milk (or other frothed beverages) in a container 10 (see Fig. 3). The housing portion contains an inner container 10 in the illustrated embodiment. This comprises a cylindrical side wall portion 1 1 , an inclined side wall portion 12 and a bottom portion 13. However, it should be noted that in particular the side wall portion 1 1 may also be of a different shape and does not have to be formed in a cylindrical shape. In the shown embodiment, a duct 14 is provided in the bottom portion 13 of the container 10 in order to provide a duct for a rod 22 of a frothing head 20. The frothing head 20 comprises a whisk 21 , which may be provided as a circular metal ring with a coil wounded around the ring in order to provide an improved frothing process. The whisk 21 is provided at one end of the rod 22, wherein on the other end of the rod 22 there is provided a mechanical coupling element 23, for example a gear part. The mechanical coupling element 23 may engage with a corresponding mechanical coupling element 53, which of course may be a meshing gear part, of the base unit 3, when the housing 2 is received on the base unit 3. When releasing the housing portion 2 from the base unit 3, the mechanical coupling element 23 will also be released from the mechanical coupling element 53. It should be noted that even if not shown, there may also be provided some spring or resilient members, which provide for a sufficient mechanical coupling between the mechanical coupling elements 23 and 53.

Within the housing, around and beneath the container, there is provided a void or sub- chamber 25. The sub-chamber is bounded by the walls of the container 10, and by walls of the housing, including bottom wall 33. Bottom wall 33 has a well 34 in which the mechanical coupling element 23 is located, and a one-way valve, a diaphragm check valve in this embodiment, schematically indicated as 35. The walls which bound the sub-chamber are of rigid material(s). Suitable materials include stainless steel, thermosetting plastics materials and thermoplastic materials which have properties at a temperature of up to 100°C. In addition to being of material(s) with suitable properties of appearance, food-safeness and toughness the walls are sufficiently thick to withstand cycles of temperature and pressure in a dishwashing machine (as will be described).

The base unit 3 comprises a drive means 50, which in the present embodiment further comprises a DC motor 51 and a rod 52 being connected to the motor. The second mechanical coupling element 53 is mounted to the end portion of the rod 52. The housing portion 2 further comprises a first electrical coupling element 31 which correspondingly engages into a second electrical coupling element 41 of the base unit 3. This connection between the electrical coupling elements 31 and 41 provides for an electrical contact between the base unit 3 and the housing portion 2 in order to provide a heating element 30 with electrical energy. It should be noted that the electrical connection between the first electrical coupling element 31 and the heating element 30 is not shown in Fig. 3. It should be noted that a heating element may be a conventional heating element as well as a heating film or a micro wave device. The heating element is provided on the obverse face of the inclined wall portion of the container 10, in order to provide a heating impact to the milk or liquid contained in the container 10. Thus the heating element is in the sub-chamber 25.

The container may be fixed to the housing portion by a press fitting or welding or soldering process at the top portion of the housing 2. The seals thereby formed are good but not adequate, in our tests, to withstand dishwashing, without the relieving properties of the oneway valve 35.

The one-way valve 35 permits air to leave the sub-chamber when the internal pressure rises, for example when the apparatus is hot, in a dishwasher, but prevents air, and water, entering the sub-chamber, when the apparatus cools down. We have found that by providing a one-way valve the contents of the sub-chamber are protected from water ingress even when the housing is washed using the highest temperature cycle in a domestic automatic dishwashing machine. It is believed that as air pressure rises with rise in temperature within the sub- chamber during a dishwashing operation it reaches an overpressure at which the one-way valve opens, and air can escape. As the temperature rises further more air can be released. When the dishwasher cools the air pressure within the sub-chamber reduces but the one-way valve prevent ingress of air, or water into the sub-chamber. The inside of the sub-chamber is left with an under-pressure or small partial vacuum relative to the external atmosphere but the construction of the housing, and the nature of the seals in it, are such that this has no detrimental effect. In subsequent dishwashing cycles the pressure in the sub-chamber cycles in a non-deleterious manner from sub-atmospheric, to a higher pressure whose upper limit is dependant on the rating of the one-way valve selected (perhaps approximately atmospheric), to sub-atmospheric; and so on.

It should be noted that the space between the housing 2 and the container 10 may be filled with an insulating material in order to avoid a heat loss from the inside of the container to the outside. The housing portion 2 may also comprise a cover 16, which may be sealed by a circumferential seal 17 to the container 10. The base unit 3 may comprise a frame construction 72, which may be covered by an outer shell 71 , which may for example be provided as a design surface of the base unit.

Further, inside the base unit 3 there may also be provided a printed circuit board 60, which may include a control circuit for controlling the driving means as well as the heating element. Onto the printed circuit board, also electronics can be provided which control the two-stage speed of operation (fast, then slow), particular sensors (not shown) which may control a sufficient heating process to not overheat the milk to be foamed; and sensors 18 which may monitor a sufficient foaming process. Foaming sensors may for example be ultrasonic sensors measuring the acoustic properties of the foamed milk, which will substantially change between a foamed and an unfoamed condition, since foamed or frothed milk has a very much higher acoustic damping coefficient compared to unfrothed milk. However, as an alternative, also visual sensors may be provided in order to monitor the filling level of the container 10. Frothed milk has a larger volume than unfrothed milk, so that based on the filling level of the container, a frothing process may be monitored. Further, a frothing process can be stopped when filling too much milk into the container 10, so that the milk frothing device can also be operated with an open cover, without the risk that the foamed milk will slop out of the container 10. For connecting particular sensors to the container 10 for monitoring the frothing process, further contacts, plugs and sockets may be provided between the housing 2 and the base unit 3, although not shown.

However, the acoustic damping of the frothed milk in the container can also be measured from the base unit, since also the acoustic properties of the environment of the base unit will change, when the milk in the container 10 will change from an unfrothed to a frothed condition.

In an alternative embodiment the heater may be ring-shaped and mounted around the rod.

In an alternative embodiment the duct for the rod may be provided through the inclined wall portion.

In an alternative embodiment the inclined wall portion may extend from one side of the container to the other, that is, there is no bottom portion 13.

It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in this association with different embodiments may be combined.

Claims

Claims:

1. Apparatus for electrically heating a food product, the apparatus comprising a housing with a container for the food product and an void adjacent to the container, the void containing electrical means, the container being upwardly open or upwardly openable to introduce the food product into it and to remove it therefrom, the void being enclosed but having, in an external wall, a device which allows air to vent from the void but prevents water from entering the void.

2. Apparatus according to claim 1 wherein the device is a one-way valve, which can allow air to pass in one direction (from the void to the external environment) but prevents air, and water, from passing from the external environment into the void.

3. Apparatus according to claim 2 wherein the valve is selected from a diaphragm check valve, a ball check valve, a stop-check valve, a swing check valve, a duckbill valve and a lift- check valve.

4. Apparatus according to any preceding claim suitable for producing frothed milk, the container having a whisk to froth milk in the container.

5. Apparatus according to claim 4, wherein the whisk is mounted for rotation at the bottom region of the container.

6. Apparatus according to claim 4 or 5 wherein the container comprises a side wall and an inclined side wall portion, wherein the inclined side wall portion is inclined with respect to the side wall.

7. Apparatus according to any of claims 4 to 6 wherein the side wall and/or the whisk are asymmetrically located within the container.

8. Apparatus according to claim 6 or 7, wherein the container has bottom wall portion and the inclined side wall portion is confined by the side wall and the bottom wall portion.

9. Apparatus according to any preceding claim comprising heater means attached to a wall of the container within the void so as to warm a food product in the container, preferably attached to the obverse face of the wall to the milk-receiving container volume.

10. Apparatus according to any preceding claim comprising a base unit to which the housing is coupled, the base unit containing a drive mechanism and further electrical component(s) selected from one or more of cables, wires, connectors, a central processing unit and a printed circuit board.

1 1. Apparatus according to any preceding claim wherein the void is a single air-space for which a single said device is provided.

12. Apparatus according to any preceding claim wherein the walls bounding the void are of a material and thickness to ensure that the walls are rigid at temperatures of up to 100°C.

13. A method of heating a food product using apparatus as claimed in any preceding claim.

14. A method of cleaning apparatus as claimed in any preceding claim after it has been used to heat a food product, wherein the method entails machine dishwashing.

15. A method of frothing milk using an apparatus with a whisk, the apparatus being as claimed in claim 4 or any claim dependent on claim 4.