This invention relates to food processors, and in particular to food processors having a cooking capability. Such appliances may take the form of a base unit and a bowl with a lid, the bowl having a tool mount, usually in the base of the bowl and optionally removable, for connecting to a drive output of the base unit. A bladed tool or stirrer tool may be attached to the tool mount for processing operations such as chopping or stirring of food in the bowl. A heater may be provided in the base unit or in the bowl for processing operations involving cooking. A plug may be provided for replacing the tool mount where a drivable tool is not required. Appliances including heaters may be known as cooking food processors.

Previously, such cooking food processors have not been suitable for pressure cooking operations, where the pressure inside the bowl is raised above atmospheric pressure in order to achieve a higher cooking temperature and increased cooking speed. This is because thelid and/or the bearing for the tool mount does not perform well under the increased pressure. The present invention aims to address this.

Thus from one aspect, the invention comprises, in a cooking food processor with a container, providing exchangeable lids attachable to the container: one for pressure- cooking incorporating an (optionally removable) seal which is resistant to at least 2 bar, one for ordinary cooking which is optionally transparent and includes an aperture the seal of which is also optionally removable. Attachment of these lids may optionally configure the appliance to different cooking tasks, e.g., attachment of the pressure cookinglid may automatically configure the machine to heat the container to maintain an internal pressure of at least 2 bar, whilst attachment of the aperturedlid may automatically configure the machine for food processing, optionally via a processor tower.

The removable seals and their respective seats within their respective lids may be as described in our co-pending application published as GB2547683, the content of which is incorporated herein. Preferably, the seals are differently sized/dimensioned such that the seal of onelid cannot be used, or cannot be correctly fitted, in the lid of the other, or at least so that the lid interlock cannot be actuated when the wrong seal is located in the lid being used. Attachment of the pressure cooker lid may also cause the machine to limit rotation of the too! to 60 RPM or less to avoid splashing which may dog the safety valve. The cooking food processor may also incorporate a selectively-activatable pressure-reduction or cooling mechanism such as a fan to cool the container and reduce pressure within it, for example for rendering the container safe to open after pressure cooking, or reducing pressure in the event of excess pressure build-up. Use of the fan may be advantageous as if is relatively simple to implement. Another example of such a mechanism, similarly capable of reducing pressure within the pressure cooker without releasing its contents, includes a cooling system such as that described in the applicant's patent pub. no. WO2017125749A2, the entire disclosure of which is hereby incorporated by reference.

Preferably, a stir tool is able to rotate in the bowl during pressure cooking.

Thus, from another aspect, the invention provides a pressure-resistant bearing seal, preferably for making the seal compression-resistant such that the container can contain a pressure of at least 2 Bar. The seal may have an increased hardness (for example above 40 Shore A), or the seal may include a metal washer to resist compression of the seal, or the seal may be located in a groove in a metal body to limit the amount of compression of the seal. The same seal may be used on a plug for sealing the aperture in the bowl. In this way a removable bearing/plug may be achieved for a pressure cooker.

Thus according to one aspect of the present invention, there is provided a food processor comprising: a bowl for receiving food to be processed, and first and second lids for selectively engaging the bowl to form a bowl assembly, the first lid comprising a first seal arranged to provide a gas tight seal between the bowl and the lid, the seal arranged to contain pressure in the bowl assembly for a first food processing operation, such as pressure cooking.

Attachment of the first lid to the bowl may automatically configure the food processor for pressure cooking, and attachment of the secondlid to the bowl configures the food processor for a second food processing operation, such a mixing, chopping, heating or cooking operations. The secondlid may be transparent for viewing the food being processed, and may include an aperture for adding ingredients. The food processor preferably includes a heater and, in the first processing configuration, the heater may be arranged to heat the bowl assembly so as to pressurise the bowl assembly, optionally to a predetermined pressure suitable for pressure cooking, preferably exceeding 2 bar. For example, the food processor may comprise a controller communicating with at least one sensor for use in determining the pressure in the bowl. More preferably, the heater is arranged to heat at least 250ml of water within the bowl assembly (which may have a capacity of approximately 2-5 litres) so as to pressurise the bowl assembly to at least roughly 2 bar. The heater preferably can heat the bowl assembly to at least 100 degrees centigrade, and more preferably can heat the bowl assembly to within the range 100-220 degrees centigrade.

The bowl may contain a tool mount for a drivable tool, and in the first processing configuration, the speed and/or torque of the tool is limited to a predetermined maximum, optionally 60rpm, so as to reduce splashing which may for example block a pressure release valve in the lid.

The first seal may be a removable seal, and the secondlid may also comprise a second removable seal. The processor may comprise a safety interlock mechanism arranged such that operation of the food processor is allowed only when the interlock mechanism is actuated. Thus the safely interlock mechanism may be arranged be actuated to allow the first processing operation only when the first lid is engaging the bowl with the first seal fitted correctly.

As a further safely measure, preferably the first seal and the second seal are configured such that they are not interchangeable with respect to the first and second lids, and/or interchanging of the seals is evident to a user, and/or the interlock mechanism is not actuated if the seals are interchanged.

The first lid may comprise a pressure release valve or safety valve, and preferably may comprise a temperature and/or pressure reduction mechanism, optionally a fan.

The food processor may comprise a base unit having a drive outlet for driving the tool mount. The heater may be provided either in the base unit or in the bowl assembly. From another aspect, the invention comprises a bearing for a bowl assembly, the bearing comprising a gas tight seal between the bearing and the bowl when fitted to the bowl, in which the seal is gas tight under pressure within the bowl, for example in order that the bowl assembly can be used for pressure cooking.

The seal may comprise an element formed of a material (for example, an elastomer) which is compression resistant, preferably a resilient material having hardness of at least about 40 Shore A, and preferably between about 40 and 80, and more preferably still 60 and 80 Shore A. The seal element may be housed in a recess provided in one of the surfaces to be sealed; eg a surface of the bearing, or in a surface of the bowl, and is preferably formed in a surface of the bearing which is arranged to abut an interior surface the bowl.

The seal may comprise a rigid member and a resilient sealing member, the rigid member being arranged to limit compression of the resilient member, and preferably being bonded to the resilient member, and optionally comprising a metallic member, such as a washer. The seal element is for example an O-ring seal.

The invention may also provide a bowl assembly for a food processor, comprising a bowl for receiving food to be processed, and alid for the bowl, the bowl assembly having an aperture, and a first component for engaging the aperture, the first component comprising a bearing as defined above. The first component may be removable, and optionally a second component is selectively engageable with the aperture, preferably in which the first component comprises a drivable tool mount and the second component comprises a blanking plug. The second component may also comprise a gas tight seal when fitted to the bowl, as defined above in relation to the bearing.

The invention also provides a food processor comprising a bowl assembly as defined above. Reference to a gas tight seal preferably refer to a seal which is gas tight under a pressure between about 1.8 bar and 2.0 bar, optionally at least 2 bar.

Any or all of the seals described above may be substantially resistant to oil within the temperature range of approximately 100-220 degrees centigrade, and more preferably approximately 160-200 centigrade. Thus they may be suitable for pressure frying operations of the food processor. The food processor may comprise one or more weight sensors configured to measure a weight of the bowl and a computer processor configured to control the food processor in response to the output of the weight sensors. Preferably, the computer processor is configured to prevent or inhibit pressure cooking when the weight of the bowl indicates that less than a predetermined minimum weight of contents is present in the bowl, or more than a predetermined maximum weight of contents is present in the bowl. The predetermined minimum weight for example may be one of: approximately 250ml of water; and a weight of an ingredient, which may be calculated based on a density of an ingredient selected by a user. The computer processor may be configured to prevent or inhibit pressure cooking when feedback from sensors associated with the bowl indicates that the contents of the bowl exceed a predetermined maximum weight and/or a predetermined fill-level.

The invention may also provide a pressure cooker comprising a bowl, a lid, a safety valve, and a rotary tool, wherein thelid comprises downwardly-depending vanes configured to impede ingredients processed by the rotary tool from obstructing the safety valve. The pressure cooker may be as defined above. Thus the bowl andlid may form a bowl assembly as defined above.

The Invention described here may be used in any appliance, such as a kitchen appliance, and/or as a stand-alone device. This includes any domestic food-processing and/or preparation appliance, including both top-driven appliances (e.g., stand-mixers) and bottom-driven appliances (e.g., food processors). If may be implemented in heated and/or cooled appliances. The invention may also be implemented in both hand-held (e.g., hand blenders) and table-top (e.g., blenders) appliances. It may be used in an appliance that is built-in to a work-top or work surface, or in a stand-alone device. The invention can also be provided as a stand-aione device, whether motor-driven or manually powered.

Whilst the invention has been described in the field of domestic food processing and preparation appliances, it can also be implemented in any field of use where efficient, effective and convenient preparation and/or processing of material is desired, either on an industrial scale and/or in small amounts. The field of use includes the preparation and/or processing of: chemicals; pharmaceuticals; paints; building materials; clothing materials; agricultural and/or veterinary feeds and/or treatments, including fertilisers, grain and other agricultural and/or veterinary products; oils; fuels; dyes; cosmetics; plastics; tars; finishes; waxes; varnishes; beverages; medical and/or biological research materials; solders; alloys; effluent; and/or other substances. Any reference to “food”, “Beverage” (or similar language) herein may be replaced by such working mediums.

As used herein, the term “processing” preferably connotes any action relating to or contributing towards transforming products into foodstuff, or transforming foodstuff into a different form of foodstuff, including - as examples - applying mechanical work (e.g. for cutting, beating, blending, whisking, dicing, spira!ising, grinding, extruding, shaping, kneading etc.) and applying heat or cold. “Food” and “foodstuff as used herein can include beverages and frozen material and material used in creating them (e.g., coffee beans). in order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which:

Figure 1 is a perspective view of a food processor;

Figure 2 is a cross sectional side view of the lid seal of the food processor of Figure 1 ; Figure 3 is a perspective view of a bowl;

Figure 4 is a cross-sectional side view of the bowl of Figure 3;

Figure 5 is a cross-sectional side view of a bearing;

Figure 6 is a perspective view of a seal;

Figure 7 is a cross-sectional side view of a seal;

Figure 8 is a perspective view of a bowl assembly, and alternative lids;

Figure 9 is a perspective view of part of the bowl;

Figure 10 is a perspective view of a locking arrangement;

Figure 11 is a perspective view of Figure 12 is a top perspective view of a lid;

Figure 13a and 13b are perspective view of a bowl; and Figure 14 is a perspective view of a food processor.

Referring to Figure 1, the kitchen appliance in the form of a food processor 1 comprises a bowl assembly 2 and a base unit 3. The bowl assembly 2 typically houses a processing tool which may be powered and controlled by the base unit 3. Alternatively or in addition, the bowl assembly 2 may be heated by the base unit 3. The bowl assembly 2 is wholly removable from the base unit 3, allowing for easy cleaning, tool changes, and loading or removal of food items for processing. The food processor may also included a processor attachment comprises a body 18 having a dispensing chute 18 which may be positioned over an aperture 17 in the bowl lid 7, a cover 20, a feed chute 22, and a cutting disc (not shown) which is powered by the second drive outlet in the base unit 3.

Referring aiso to Figure 2, the bowl assembly 2 comprises a bowl 5 and alid 7. Thelid 7 is removable to allow the interior of the bowl 5 to be accessed. Thelid 7 is arranged to form a seal with the bowl 5 when fitted to prevent food items being ejected from the bowl during processing. Thelid 7 may comprise an inner component 8 and an outer component 10. A lid seal 12 may be received between the components 8, 10 for sealing against an upper edge of the bowl 5. The processor may comprise a safety interlock for allowing operation of the processor only when thelid is correctly fitted, with the seal correctly fitted in the lid, as described in our co-pending application published as GB 2547683, as mentioned above.

According to the invention, the processor includes a furtherlid for use as an alternative to thelid shown in Figures 1 and 2 comprising alid seal which is gas tight under pressure, to allow the bowl assembly to be used for pressure cooking. Such alid does not have an aperture as shown in Figure 1 , but includes a safety valve/pressure release valve as is known in the field of pressure cookers. The further lid may for example be of a one-piece configuration, rather than having inner and outer components. The further lid preferably has a mechanical locking arrangement with the bowl. The seals or the lids preferably have a different configuration such that the seals are not interchangeable, or so that the safety interlock mechanism prevents or inhibits operation if the correct seal is not fitted to the lid.

The safety valve/pressure release valve may be a float valve, spring-valve, counter- weight valve, or other valve for releasing pressure from the pressure cooker, for example when it exceeds a pre-determined amount. Preferably the valves are configured such that at least two different predetermined pressures may be selected. For example, where a spring-valve is used the tension of the spring may be adjusted so as to adjust the pressure at which the valve will open. The pressure in excess of atmospheric pressure is preferably variable between approximately 0.3 bar (correspond to the minimum pressure required for cooking e.g., legumes) and 2 bar, either continuously or between discrete settings - continuous variance is preferred for flexibility whilst discrete settings are preferred for ease-of-use. Alternatively two or more safety-release valves may be provided and inter-changed depending on the desired release-pressure, either by having a single seat into which different valves may be screwed, or by having two or more valves located in thelid and providing a mechanism whereby one valve may be prevented from opening whilst the other is permitted to open (e.g., a pivoting or sliding shutter/blocking element).

The safety valve/pressure release valve is preferably actuatable via one or more solenoids and/or motors powered and controlled by a central processing unit (CPU) of the processor. The CPU may control the valve to open to release pressure, or vary the pressure at which the valve automatically opens. The CPU may control the valve either responsive to user input (e.g., the pressing of a button on a user interface indicating that the user wishes to depressurise the bowl 5) or according to a pre-programmed series of instructions (e.g., steps in a recipe), with instructions being triggered either by the expiry of a time interval or by the user providing an input indicating that the next instruction should be carried out. Heating and rotation of the tool may similarly be controlled by the CPU.

Interlocking of the lids and/or seals can be achieved by incorporating a magnet into the lid/seal corresponding to one or more reed-switchs in the bowl and/or base of the appliance. Alternative one or more micro-switches may be actuated by the lid and/or seal, optionally via a push-rod arrangement, when thelid and/or seal are present. A further option is to incorporate an RFID, NFC, or similar tag in which current may be induced by the bowl/base into the lid and/or seal and an identifying radio-signal (as well as optionally other telemetry including the output of temperature sensors and other sensors) transmitted in response. Regardless of the interlocking switch mechanism used, the CPU in electronic communication with it can recognise based on its output when either, or both, of the seal and the lid are present, and whether they are the appropriate seal and/orlid for pressure cooking. Based on output of the interlocking switch mechanism, the CPU can permit activation of either, or both, of the heating element and the motor for driving the tool, to carry out pressure-cooking. The CPU may also control the depressurising mechanisms (e.g., cooling the bowl or releasing pressure) described above responsive to software instruction (including recipes) and user input.

The furtherlid may include one or more temperature and/or pressure sensors. These may be simple mechanical temperature/pressure gauges that are visible to the user, or electronic sensors in electronic communication (via RF or wired connection) to a CPU of the appliance.

Referring to Figures 3 and 4, the bowl assembly 2 comprises a bowl 5 having a bottom surface 14, which is preferably flat. The bowl 5 preferably has a circular cross-section, in order to promote the even heating or processing of food. The base section 14 may have a smaller diameter cross-section than that of the bowl 5.

The bowl 5 comprises a bowl support 24 arranged on the bottom of the bowl 5, configured to engage with the base unit 3 when the bowl assembly is mounted on the base unit. The bottom surface 14 of the bowl 5 comprises an aperture 26 which may sealingly receive a component, as will be described below. The aperture 26 preferably has a non-circular shape and may additionally be keyed, so as to prevent the rotation of a component received into the aperture 26. The aperture 26 is preferably located in an indented section 28 of the bottom surface 14. The indented section 28 is preferably circular in shape, and is preferably located centrally on the bottom surface 14.

The bowl support 24 preferably comprises an outer wall 30 extending from the bottom surface 14, defining a chamber 32 beneath the bowl 5, and an inner wall 34 having an opening 36 aligned with the aperture 26 in the bowl 5.

The bowl support 24 may hold a heating element 38 adjacent the base 14 of the bowl 5 for heating the contents of the bowl. The heating element 38 may be attached to the bowl support 24 by fasteners 40. The heating element may be electrically powered and, preferably, also controlled by the base unit 3. The heating element 38 is preferably annular or ring-shaped so as to promote the even processing of ingredients. Preferably, a resistive heating element is used, being bonded to the bottom surface 14, although other heating elements may be used, including thick-film heaters, inductive heating either integral to the bowl or induced by an element in the base unit 3, and other heating means. The heating element is preferably sealed to prevent any fluid from contacting the heating element, using a heat resistant and relatively heat conductive material, for example, a heat resistant polymer such as silicone.

Figure 4 also shows components which can be engaged to the bowl 5, such as are known from our co-pending application published as GB2548327. The known components may comprise a driveable tool mount 42 for receiving a processing tool 44, a blanking plug 48, a ring-shaped sealing member 50, and a locking arrangement 52. The sealing element 50 may be an “O”-ring seal. The tool mount 42 may be comprise a bearing housing 53 for a drive shaft 54 which is engagable with the tool 44 for rotating the tool via a tool coupling 57. The drive shaft 54 has a drive coupling 59 for engaging a drive outlet of the base unit 2.

The driveable tool mount 42 and the blanking plug 48 may be arranged to be interchangeable components, each of which (together with the seal 50) can be received in the aperture 26 and be sealingiy engaged by the locking arrangement 52. The components each comprise a lip 55, with the sealing element 50 being disposed between the lip 55 and the interior surface of the bowl 5, in this case the recessed part 28. The locking arrangement 52 is shown as a separate component, but it can also be integral to the bowl and allowed to move to the extent that it can engage the driveable tool mount 42 or the blanking plug 48.

With this arrangement, if the bowl assembly is pressurised, which would for example be required for a pressure cooking process, pressure on the bearing housing 53 or the blanking plug body 48 would tend to cause the component to move downwardly, compressing the seal 50 further, and causing the locking arrangement 52 to become loose and potentially disengage. For example, compression of the seal element 50 at pressure may allowing the locking ring to rotate freely, and the locking ring could potentially vibrate free, such that when the pressure is released the aperture is not sealed, allowing the bowl contents to leak.

Referring now to Figure 5, according to the invention, a bearing assembly 60 comprises a housing 62 and a tool coupling 64, with a drive shaft 66 extending from a drive coupling 68 through the housing to engage with the tool coupling for driving the tool, in a similar manner to the known tool mount 42 of Figure 4. The drive shaft 66 runs in a series of bearings 70 formed in the housing 62, and the housing also including an upper and lower seal 72, 74 at either end of the series of bearings. A locking nut 76 is provided to engage the housing so as to retain the bearing assembly 60 in place in the bowl aperture. The locking nut 76 clamps the base 78 of the bowl between the nut 76 and the assembly housing 62. The join between the drive shaft 54 and the tool coupling 64 may be covered by a cap 69 to prevent ingress of material between the two. A sealing element 80 is provided between the housing 62 and the inner surface 82 of the bowl, and is arranged to be compressed so as to form a seal when the locking nut is tightened. The lower surface of the housing is formed with a shoulder 84 and a recessed portion 86. The seal 80 is located in the recessed portion 86, such that abutment between the shoulder 84 and the bowl surface 82 limits compression of the seal 80. Thus, under high pressure conditions, where the bearing housing 62 experiences a downward force, the housing cannot travel further downwards and thus the locking assembly 76 remains tight.

This arrangement can also be used for a bowl plug. The bowl plug may be adapted to include a shoulder and recessed portion as shown in Figure 5 in relation to a tool mount bearing, and may be used with the same sealing element 86.

Other structures may be envisaged so that compression of the seal, and corresponding travel of the bearing housing or bowl plug housing, is limited. For example, as shown in Figure 7, a sealing element 88 may be housed in a groove 90 in the bearing housing 92, such that a seal is formed with an interior surface 94 of the bowl.

As another alternative, a sealing element 95 may be in the form of a rigid element such as a metal ring 96 bonded or otherwise attached to a flexible or compressible element such as a seal ring 98. Such a sealing element 95 may be used with the bearing shown in Figure 4. The width of the metal ring is smaller than that of the seal ring 98 when uncompressed. Compression of the seal element 95 between the bearing 42 and the bowl 28 is limited to the width of the metal ring 96. Thus the housing is prevented from further downward travel as before, such that the bearing remains locked in position sealing the bowl aperture.

The bowl 5 may include markings within it to indicate the maximum fill-level of the bowl. For example it may have marking indicating where it is 2/3rds full for non-expanding food and liquids, ½ full for foods that may expand during cooking, It may also have markings indicating the minimum filling for the bowl, which should be roughly 250ml of water or more in a typically-sized bowl (e.g., 2-5 litres capacity) to ensure pressurisation by evaporation of the water. The seal 80, the seal of the further lid, and the bowl 5 and furtherlid itself, as well as all other sealing elements, are preferably resistant to heated oil, so that the bowl 5 may be used for pressure-frying (also known as ‘Breasting’). For example they are preferably formed of an oil-resistant elastomer which will either not absorb oil at the temperatures and pressures used in pressure-frying (100-220 degrees centigrade, and more preferably 160-200 degrees centigrade, and 0.3-2 bar pressure) or will only absorb minima! amounts such that they will not significantly swell or weaken when exposed to heated oil for significant periods of time (e.g., minutes or longer). Examples of such elastomers include fluoreslastomers such as those of the FKM family, which includes Viton™ (originally available from the DuPont company of Wilmington, Delaware, US, now known as The Chemours Company). Silicone and PTFE, can also have a similar oil resistance. Suitable seals and materials for pressure-frying may also be obtained from the Henny Penny company of Eaton, Ohio, US, and Pandet Limited of South Wigston, Leicestershire, England (operating under the Kuroma™ brand). Similarly, where pressure frying is intended, the tool mounted in the bowl should be made of a materia! resistant to heated oil (e.g., a metal or heated-oil-resistant plastic).

The CPU of the appliance can include one or more stored pressure-frying programs including recipe-steps for pressure-frying. Activation of a pressure-frying program by a user via the user interface can cause the CPU to control the heating element and stir- tool to carry out pressure-frying, with steps that must be performed by the user being displayed as instructions to the user via the user interface and a button being pressable to indicate that the user's step has been done. An example of such a pressure-frying recipe is shown in pat. pub. no. US3245800 to H. Sanders, the entirety of which is incorporated herein via reference.

Particularly during pressure-frying operations due to the danger of heated oil, but also optionally in other pressure-cooking operations, the appliance may be configured to prevent removal of the lid until the pressure and/or temperature of the bowl and its contents has dropped sufficiently to allow it to be opened safely. This may be achieved mechanically, by, for example, using a spring-loaded element that extends against the force of the spring so as to block a lid-latch from being unlatched under the force of pressure within the bowl when the pressure is higher than e.g., 0.3 bar, but which unblocks the latch once the pressure reduces to less than e.g., 0.3 bar. Indeed, very simple control of the heating of the bowl 5 may be achieved by mechanically connecting the above-described spring-loaded element to an interlock such as the interlocks 115 and 117 described later (which may also be implemented in bowl 5). In this way the CPU ceases or reduces heating of the bowl 5 when the micro- switches 211 (described later) are actuated/released by the interlock rods 115 and 117 under the actuation of the spring-loaded element.

It may additionally or alternatively be achieved electronically by the CPU locking the lid using e.g., a solenoid when feedback from sensors associated with the bowl indicate a pressure higher than 0.3 bar, or a temperature higher than e.g., 50 degrees centigrade. Alternatively or additionally to this, the CPU or the mechanical lock may cause a sign indicating that it is not safe to open the pressure cooker to be shown to the user whilst dangerous conditions prevail inside the bowl.

A further exemplary embodiment of a food processor bowl arrangement suitable for pressure cooking 100 is shown in Fig. 8. The bowl arrangement 100 consists of a bowl 110 which is attachable to a base-unit using spring-loaded latches 111 , and two interchangeable lids 120, 130. The bowl 110 also has handles 112 including interlocks for identifying whether alid is attached, and preferably whichlid is attached. The handles 112 also include triggers 114 which can be actuated to release the latches 111 for removing the bowl 110 from the base. The main body of the bowl 110 is water-tight for receiving ingredients to be cooked or otherwise processed, and has graduation marks 113 on an inner surface for showing the fill-level of the bowl 110. The bowl 110 may optionally also have a pressure-resistant transparent window in its side wail so that the fill level may be seen from the side.

One of the interchangeable lids 120, 130 is a food processinglid 120. The food processinglid 120 has attachment extensions 121 extending on it which latch onto the bowl 110 via the handles 112. The food processinglid 120 has multiple ring-shaped components 122, 123, 124 arranged concentrically with each serving a specific purpose. The outermost component 122 is a bowl attachment ring preferably made of metal or another relatively strong and durable material for maintaining a rigid attachment and seal via a removable sealing gasket (not shown) to the bowl 110 for preventing sideways escape of heated water. Within the bowl attachment ring 122 is a transparent ring 123 which enables the user to view the food during processing. Within the transparent ring 123 is a measuring cup receiving ring 124 preferably made of a scratch-proof material such as plastic, which receives the measuring cup 125. When the measuring cup 125 is not received in the receiving ring 124 an aperture is uncovered which can be used to putting ingredients into the bowl 110 during processing, but is preferably dimensioned so that a hand cannot fit through it for safety.

The other of the interchangeable lids 120, 130, is a pressure-cookinglid 130. Similarly to the food processinglid 120 this has attachment extensions 131 extending from it which mate with an upper surface of the handies 112 to attach the pressure-cookinglid 130 to the bowl 110. The lid 130 has a removable sealing gasket (not shown) that can form a gas-tight seal with the bowl 110 to withstand pressures of up to approximately 2 bar, with the seal preferably held compressed between thelid 130 and the bowl 110 by the attachment extensions 131. A pressure-release valve 132 is provided in the centre of the lid 130, with a manually actuatable toggle 133 for manually releasing pressure from within the bowl 110.

Figure 9 shows a detailed drawing of one of the handles 112. The handle 112 achieves recognition of which of the interchangeable lids 120, 130 is attached to it, and whether or not the removable sealing gasket is present, using the interlocks 115, 116, and 117. The attachment extensions 121 of the food processinglid 120 include at least one actuator rod (not shown) that fits within the slot in which the first interlock 115 is located and depresses the interlock 115. A second interlock 117 is located in the handle 112, at a different radius relative to the central major axis of the bowl 110 to that of the first interlock 115, which is similarly actuated by an actuator rod in the attachment extension 131 of the pressure cooker lid 130. To further help prevent accidental actuation, the second interlock 117 may also be located at a different point along the circumference of the bowl 110 and in a differently-sized (e.g., smaller) slot to that of the first interlock 115. In this way, depending on which interlock is actuated, the appliance can recognise which lid is attached. A further interlock 116 is provided to identify whether or not the removably-attachable gasket is fitted to thelid - there may be only a single gasket interlock 116, or more than one may be provided located such that the gasket of the processor lid 120 actuates one of the gasket interlocks 116 and that of the pressure cookinglid 130 actuates another. To hold the lids 120, 130 on the bowl 110, one or more tabs (not shown) extend inwardly form a lower rim of the eachlid 120, 130 which, when the lid 120, 130 is rotated into the attached position are held under the holding element 118. The holding element 118 is preferably ramped such that the more the tab is rotated under the holding element 118, the greater the pressure applied on the gasket between the lid 120, 130 and the bowl 110 is. Alternatively the inwardly-extending tabs of the lids 120,130 may be spring- loaded such that they can be retracted to allow the lid 120,130 to drop down on to the bowl 110, and then extended under the holding element 118 to lock it in place. The interlocks 115, 116, and 117 may be ramped to allow their actuation horizontally as well as a vertically, or even recessed/covered so as to allow only horizontal actuation to further prevent accidental actuation.

An example of the working of the interlocks 115, 116, and 117 can be seen in Figures 10 and 11. In this example the interlocks 115 and 117 are formed as push-rods that are actuated by their respective lids 120, 130. To protect and guide the movement of the push-rod interlocks 115 and 117, they are encased by a hollow column 119 extending down the side of the bowl 110. The trigger mechanism 114 for the latch 111 also runs through the column 119. The push-rod interlocks 115 and 117 are spring-loaded by coil springs at a lower extremity to return them to their extended position when not depressed. The lower extremity of the push-rod interlocks 115, 117 forms a pin that can extend outside the column 119 to actuate microswitches 211 located in a recess 210 in the appliance 200 to indicate that one of the lids 120, 130 is attached. The microswitches 211 are in electronic communication with a CPU of the base 200 which can, e.g. prevent operation of the heating element or limited a maximum output of it, prevent operation of a stir-tool or other rotary food processing tool or limit the maximum speed of it, and allow the carrying out of specialised programs (e.g., a pressure cooking program or pressure frying program), responsive to the actuation of the microswitches 211.

The recess 210 is shaped so as to receive the column 119 and prevent rotation of the bowl 110, and also includes a notch 212 for receiving the latch 111. However, another way of receiving the bowl 110 could be configured, including having the microswitches 211 located in a slot having a holding element under which a protrusion of the bowl 110 is rotation, or the bowl 110 being rotated until the spring-loaded latch 111 is received in a notch. Depressing of the gasket interlock 116 by the removable gasket of the lid 120 permits rotation of the lid 120 to actuate the food processor lid interlock 115, in the same fashion as the operation of the gasket/seal interlock tab in the applicant's pat. pub .no. WO2017144914A1 which is hereby incorporated by reference. In this way the lid interlocks 115 and 117 cannot be actuated in the absence of a gasket and the appliance thus ensures that it is not operated without the gasket being present. In this configuration the same gasket is presumed to be suitable for both food processing and pressure cooking. in order to modify this configuration to distinguish between the gasket of the food processolrid 120 and that of the pressure cooker lid 130, if is only necessary to provide a further gasket interlock 116 positioned to prevent the depression of the interlock 117 unless it is depressed by a gasket of the pressure cooking lid 130 which is differently- dimensioned (e.g., wider) to the gasket of the food processor lid 120, so that the gasket of the food processor lid 120 will not depress it. in this configuration it is assumed that the gasket of the pressure cooker lid 130 is different to that of the food processing lid 120 - for example that of the food processinlgid 120 may be insufficiently heat, pressure, or oil resistant for use in pressure cooking/frying, but may instead be cheaper or lighter.

A variation on the above-described food processing bowl arrangement 100 is shown in Figs. 12-13b. The pressure cooker lid 300 is otherwise identical to the lid 130 except in that the valve 301 is not positioned centrally but instead offset to make way for a central handle 302 which may include a display displaying whether it is safe to open the lid or not as discussed above. Additionally, instead of having attachment extensions the lid instead just has an interlock actuator 301 for actuating the pressure cooker lid interlock 117 when it is attached to the bowl 400 by inserting protrusions of the bowl through the apertures 304.

Similarly, the bowl 400 is identical to the bowl 110 except that its handies 401 extend so as to extend above the actuators 301 when the lid 300 is attached to the bowl 400, and has additional lid-holding protrusions 402, such that thelid 300 may potentially be secured at four different locations about its periphery, preferably each location separated by 90 degrees from the others. This enhances the securing of the lid 300 to the bowl 400, and ensures a better seal between the two. The bowl 400 further includes an additional side-handle 403 extending vertically along the side of the bowl 400 for better manipulation of the bowl 400.

Figure 14 shows the bowl 400 with thelid 300 attached to the base 200 to form a completed appliance 500. The base 200 has a user interface 220 that may be, for example, be a touch-screen interface allowing recipes and other functionalities to be selected by the user using, e.g., menus. The user interface 220 may also provide feedback regarding temperatures, feedback from weight sensors, time-elapsed in cooking processors, and other status indications about the machine. Alternatively or additionally to control of the machine via the user interface 220, the control knob 230 may also be used. The base 200 has a motor located within a motor housing 240 which transmits rotation power to the tool via the tool mount 42 via a suitable gear-train or drive-belt.

As discussed above the base 200 includes a computer processor or CPU (not shown) that can receive feedback from any electronic sensor within the appliance 500 via wired or wireless connection. Similarly, the CPU may issue instructions to any motor, heating element, or display of the appliance 500. The base 200 may further include a suitable internet connection for transmitting and receiving information from the internet, including, e.g., recipes (including recipes for pressure cooking) and appliance telemetry.

The base 200 may further include weighing scales/sensors connected either to feet of the appliance, or to the seat within which the bowl 400 is received. The CPU may be programmed so as to require that at least the required amount of water need for pressure cooking (e.g., roughly 250ml for a 2-5 litre bowl) is detected inside the bowl by the weight sensors before pressure cooking operations may be carried out. Additionally the CPU may also prevent pressure cooking, heating, or operation of the motor if feedback from the weight sensors indicate that the bowl is over-filled. For example, pressure cooking may be prevented if the bowl is filled more than 2/3rds full to prevent the possibility of boiling food matter being expelled. The maximum allowed weight may be calculated by assuming the food matter is approximately as dense as water or some multiple of this - e.g., twice - and using the resulting weight to calculate the maximum allowed weight that would fill the bowl to 2/3rds full. Alternatively the user may input a type of food being cooked and the CPU may calculate a weight indicating that the maximum fill level has been surpassed based on a stored density of that food, or may access and download a density of the food via the internet. in addition or alternatively to restricting a rotational speed of the tool mount 42 to prevent heated material contacting the valve 132, 301 during pressure-cooking to prevent the ejection of heated material through it and to prevent it becoming clogged with food matter to e.g., ~60 rpm, the pressure cooker lids 130, 300 may be modified. For example, they may feature vanes or fins depending from a lower surface of them to break up any vortex formed within the bowl by the rotation of the tool. it should be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.