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Title:
VALVE FOR A KITCHEN APPLIANCE
Document Type and Number:
WIPO Patent Application WO/2018/007831
Kind Code:
A1
Abstract:
A valve for a container of a kitchen appliance comprises an over-pressure emission valve, which may be provided in a lid of the container. The valve comprises a plug for blocking an aperture in the container, wherein the plug is biased towards the aperture such that if over-pressure develops within the container which exceeds a predetermined value the plug is expelled from the aperture to dissipate the over-pressure, and the biasing force then returns the plug to a position blocking the aperture. The predetermined value of the overpressure required to move the plug is less than approximately 15000 N/m2

Inventors:
SEALY JAMES JOSEPH (GB)
Application Number:
PCT/GB2017/052008
Publication Date:
January 11, 2018
Filing Date:
July 07, 2017
Export Citation:
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Assignee:
KENWOOD LTD (GB)
International Classes:
A47J43/07
Foreign References:
JP2004275416A2004-10-07
CN101940442A2011-01-12
KR101407018B12014-06-12
CN205215068U2016-05-11
Attorney, Agent or Firm:
HECTOR, Annabel Mary (GB)
Download PDF:
Claims:
CLAIMS:

1 . An over-pressure emission valve for a container of a kitchen appliance, the valve comprising a plug having a first position blocking an aperture in the container, the plug being biased towards the first position by a biasing force arranged such that an over-pressure within the container comprising a positive pressure differential which exceeds a predetermined value, causes the plug to move to a second position away from the aperture so as to dissipate the over-pressure, the biasing force being operable to return the plug to the first position upon the absence of overpressure in the container, wherein the predetermined value is less than approximately 15000 N/m2.

2. The over-pressure emission valve of claim 1 , wherein the biasing force is arranged such that the predetermined value is less than approximately 5000 N/m2.

3. The over-pressure emission valve of any preceding claim, wherein the biasing force is arranged such that the predetermined value is less than approximately 500 N/m2, or less than approximately 280 N/m2,

4. The over-pressure emission valve of any preceding claim, wherein the biasing force is arranged such that the predetermined value is less than approximately 50 N/m2.

5. The over-pressure emission valve of any preceding claim, wherein the biasing force is arranged such that the predetermined value is at least about 25Nm2.

6. The over-pressure emission valve of any preceding claim, wherein the biasing force is provided at least partly by gravitational force acting on the plug.

7. The over-pressure emission valve of any preceding claim, wherein the biasing force is at least partly provided by a resilient element.

8. The over-pressure emission valve of claim 7 wherein the resilient element is selected from one of a helical spring, a leaf-spring, and a pneumatic piston.

9. The over-pressure emission valve of any preceding claims, wherein an underpressure within the container, the under-pressure being a negative pressure differential which exceeds a predetermined value, causes the plug to move away from the aperture so as to dissipate the under-pressure.

10. A lid for a container of a kitchen appliance comprising the over-pressure emission valve of any preceding claim.

1 1 . The lid of claim 10, wherein the over-pressure emission valve is connected to the lid by a hinge.

12. The lid of claim 1 1 , wherein the plug is connected to the lid by a pivotable arm so as to movable between the first and second positions. 13. The iid of claim 10, wherein the lid further comprises guiding members arranged to maintain the plug in a predetermined orientation and position relative to the aperture during movement between the first and second positions.

14. The lid of claim 10, wherein the lid further comprises a hollow channel communicating with the aperture, an inside surface of the channel forming a sealing contact with the plug, and the plug travelling along the channel between the first and second positions.

15. The iid of any preceding claim, wherein the lid and/or the plug are configured to be water resistant.

18. The iid of any preceding claim, wherein the plug is formed at least partly from a transparent material. 17. The lid of any of claims 10-16, wherein the lid is configured to be frictionally fitted to a container.

18. A kitchen appliance container comprising the lid of any of claims 10-17, and a tool for processing food, in which the fool is preferably a rotary tool.

19. The kiichen appliance container of claim 18, in which the over-pressure sufficient to cause the plug to move towards the second position does not exceed an overpressure sufficient to overcome the frictional force between the lid and the container.

20. The kitchen appliance container of claim 18 or 19, wherein the kitchen appliance container is of sound-attenuating construction such that a sound within the container caused by operation of the rotary tool of 80-95 dB(A) is attenuated to 79 dB(A) or less outside the container when the plug is located within the aperture.

21 . A kitchen appliance comprising the kitchen appliance container of any of claims 14-16, and further comprising a motor for driving the rotary tool. 22. The kitchen appliance of claim 21 , further comprising a PCB, and one or more presence sensors for detecting the presence of at least one of the plug or the lid in electronic communication with the PCB, wherein the PCB is further in electronic communication with the motor and controls the motor dependent on the presence information, and wherein the PCB applies a wait-time before controlling the motor based on a change in presence information.

23. The kitchen appliance of claim 22 wherein the wait-time is 0.5-5 seconds.

24. The kitchen appliance of claim 22 wherein the wait-time is 5-30 seconds.

25. The kitchen appliance of claim 22, further comprising weighing scales.

26. A food chamber for a kitchen appliance, the chamber comprising: a container having a lid, the lid arranged to be fitted to the container with a frictional fitting force; and a valve comprising a plug having a first position blocking an aperture in the chamber, the plug being biased towards the first position by a biasing force arranged such that an over-pressure within the container of less than the frictional fitting force causes the plug to move towards a second position away from the aperture so as to dissipate the over-pressure, the biasing force being operable to return the plug towards the first position upon a reduction of overpressure in the container.

27. A lid for a container of a kitchen appliance, the lid having an access aperture for accessing the container with the lid attached, and a plug having a first position blocking the aperture and being biased towards the first position by a biasing force, and a second position away from the aperture so as to allow use of the aperture, the biasing force being arranged such that an over-pressure within the container causes the plug to move at least partially towards the second position so as to dissipate the over-pressure, and to return to the first position upon a reduction in over-pressure.

Description:
Valve for a Kitchen Appliance

Field The present invention relates to a valve for a kitchen appliance and, more particularly, to a lid for a kitchen appliance such as a blender having a valve for releasing overpressure, which may be in the form of a noise-reducing removable plug.

Background

Typically kitchen appliances, such as food processors and food processing attachments, stand mixers, and blenders are provided with a container in which food is processed by motor-or-hand-driven tools that typically grind, chop, whisk, mix, blend, or cut food. To prevent egress of food from within the container to the outside environment the container is typically provided with a lid. As it is desirable to be able to add working medium into the container during operation of the kitchen appliance, a hole is often formed in the lid.

Particularly in blenders which operate a high speeds (e.g., 35,000 RPM) and often have frusto-conicaiiy-shaped containers that serve to amplify the noise directed to the opening of the container, but also in other kitchen appliances, operation of the appliance creates significant noise levels. These noises, particularly in blenders, may be at high frequencies that are particularly unpleasant to users as they sound like screams, shrieks, howls, or roaring. Whilst these average around 79 dB(A) for most blenders, depending on the machine in question and the hardness of the working medium being processed these noise levels may be higher. In some cases they can exceed 80 dB(A) (the first action level under EU directive 2003/10/EC, which requires that employers make hearing protection available if their workers are exposed to it) or even 85 dB(A) (the second action level, at which use of hearing protection becomes mandatory for employees and this requirement should be enforced by employers). The noisiest blenders can reach sound levels of 95 dB(A). These noise levels, if emitted into the environment, may therefore be harmful to users and, where the appliance is used in a place of work, place the operators under specific legal requirements. It is therefore desirable to prevent noise emission from the container. One solution is to block the hole in the lid of the kitchen appliance with a removable plug or filler cap. However, particularly in blenders but also in other kitchen appliances, when operation of the appliance begins working medium can surge upwardly, creating a pressure-wave that can force the lid or plug of the appliance off the container. Additionally pressure can build up within heated appliances where water is converted to steam that may also blow the lid off the container.

Whilst it is possible in some circumstances to lock the lid to the container and the plug to the lid, where the container is made of glass or a similar substance it is difficult to form durable locking elements in it for the lid to engage with. Moreover it is desirable to users that the lid should be easily attached and detached, and locking elements detract from this, so relatively weak frictional fits are preferred as they permit the lid to be easily inserted into and removed from the container. These frictional fit lids typically require a force of only 15-25 Newtons applied in an upwards direction to overcome the friction holding them in the container, which for a typical lid of roughly 13 cm across requires an over-pressure of only 280-500 Newtons/metre 2 within the container of the appliance to apply. Even with smaller lids with much higher friction, the pressure necessary to remove a frictionally-fitted lid will not exceed 5% of an atmosphere {-5000 N/m 2 ). At worst, this issue can lead to limiting of performance variables such as the speed of operation of the kitchen appliances to prevent forces developing that may cause the lid to blow off.

To address this problem plugs and lids have been provided with through-holes permitting the emission of over-pressure (i.e., pressure in excess of atmospheric pressure within the container, including temporary imbalances of pressure within the container between zones of higher pressure and zones of lower pressure), or to equalise a pressure differential between the inside and outside of the container. However, these holes, even if baffled, still also permit the emission of significant amounts of noise from the container, and allow airflow that may cause oxidisation and spoiling of the working medium.

Additionally, where the kitchen appliance is provided with scales, removal of the plug requires taring of the scales due to the lost weight of the plug. The present invention is directed to at least partially ameliorating the above-described problems.

Summary of invention

The invention provides a valve for a container for a food processor, provided in the wail or lid of the container such as a blender jug or goblet, which is biased towards a first closed condition, in which the container is preferably substantially sealed, and which is movable towards a second open condition in order to dissipate pressure in the container when the pressure differential in the container exceeds a predetermined level, which level is a relatively low level, for example between about 5000N/m 2 and 15000N/m 2 , or lower.

Thus, in a first aspect of the invention, an over-pressure emission valve for a container of a kitchen appliance is provided, the over-pressure emission valve comprising a plug for blocking an aperture in the container in a first position thereof, wherein the plug is biased towards the aperture by a biasing force such that an over-pressure within the container results in the plug being expelled from the aperture or moved towards a second position to dissipate the over-pressure, and the biasing force then returns the plug to a position blocking the aperture. Overpressure within the container as used herein means a positive pressure differential between the interior and exterior of the container which exceeds a predetermined value.

This over-pressure emission valve may avoid the formation of over-pressure sufficient to remove a lid or other frictiona!iy-fitted element from a kitchen appliance. For example, the over-pressure or predetermined value of the pressure differential necessary to cause movement of the plug may be up to approximately 15000 N/m 2 , or approximately 15% of an atmosphere. Thus, a pressure differential is not able to form which is sufficient to cause displacement of a lidsecured to the container by known latching mechanisms such as thin plastic tabs (eg 2-3mm thick) or other mechanisms used with lids which are intended to be easy to remove.

Alternatively, the predetermined value of the pressure differential necessary to cause movement of the plug may be up to about 5000 N/m 2 or approximately 5% of an atmosphere. This may avoid the formation of over-pressure sufficient to remove the most firmly attached frictionally-fitted lid or other element.

The overpressure may for example be caused by an increase in air pressure in the container, or a mechanical force of ingredients striking the container, caused by operation of the appliance.

Thus there is no requirement for the lid or filler plug or cap to be provided with holes, and the plug may seal tightly with the aperture, facilitating noise reduction.

The pressure differential necessary to cause movement of the plug may be less than approximately 500 N/m 2 or 0.5% of an. Thus an over-pressure sufficient to remove a typically firmly-attached lid or other frictionally-fitted element from a kitchen appliance may be avoided. Alternatively, the pressure differential may be less than approximately 280 N/m 2 or about 0.28% of an atmosphere, such that over-pressure sufficient to remove a typical lid or other frictionally-fitted element from a kitchen appliance may be avoided.

The predetermined value of the pressure differential may alternatively be less than approximately 50 N/m 2 or about 0.01 % of an atmosphere, so as to avoid the formation of over-pressure sufficient to remove a weakly-attached lid or other frictionally-fitted element from a kitchen appliance.

The over-pressure which results in movement of the plug is preferably sufficient that the plug is normally closed or in the first position. Thus a pressure differential of at least about 25N/m 2 .may be required to cause movement of the plug.

The biasing force may be provided at least partly or entirely by the weight of the plug. This simplifies construction.

Optionally, the biasing force is at least partly provided by a resilient element. This allows the operation of the valve without the assistance of gravity (e.g., on a slope or upside- down) rendering the valve more versatile. The resilient element may be selected from one of a helica! spring, a leaf-spring, and a pneumatic piston. This allows for cheap construction.

The present invention also extends to a container of a kitchen appliance comprising an over-pressure emission valve as defined above.

The over-pressure emission valve may be connected to the lid for example by a hinge or a flexible member. This avoids the valve becoming separated from the lid whilst still allowing it to be placed in and removed from the aperture.

Optionally, the lid further comprises at least one guiding element such as one or more posts for maintaining the plug in a correct orientation and position relative to the aperture when it is expelled from the aperture. This keeps the plug oriented and positioned correctly to allow it to fall back into the aperture.

Optionally, the lid further comprises a hollow channel or column, such as a blind column, the inside of which forms a sealing contact with the plug, and into which the plug rises when expelled from the aperture. This allows the dissipation of over-pressure whilst limiting the release of sound from within the container to which the lid is attached.

The scope of the invention extends to a kitchen appliance container comprising the above-described lid, and a rotary tool for processing food.

Optionally, the kitchen appliance container is of sound-attenuating construction such that a sound within the container caused by operation of the rotary tool of 80-95 dB(A) is attenuated to 79 dB(A) or less outside the container when the plug is located within the aperture. This protects people near the container from harmful noise.

The invention extends to a kitchen appliance comprising the above-described kitchen appliance container, further comprising a motor for driving the rotary tool, such as a kitchen blender or food processor.

Optionally, the kitchen appliance further comprises a PCB (printed circuit board), and one or more presence sensors for detecting the presence of at least one of the plug or the lid in electronic communication with the PCB, wherein the PCB is further in electronic communication with the motor and controls the motor dependent on the presence information, for example to cause the motor to reduce speed or stop when the plug and/or the lid is not present. The PCB may apply a wait-time before controlling the motor based on a change in presence information. This prevents the motor being controlled based on changes in presence information which are only temporary.

For example, the wait-time may be 0.5-5 seconds. This permits the emission of overpressure without causing the PCB to control the motor based on the status-change. Optionally, the wait-time is 5-30 seconds. This permits the temporary removal of the plug or lid for addition of ingredients without causing the PCB to control the motor based on the status change.

Optionally, the kitchen appliance further comprises scales. This allows for weighing of ingredients.

According to another aspect, the invention provides a food chamber for a kitchen appliance, the chamber comprising: a container having a lid, the lid arranged to be fitted to the container with a frictional fitting force; and a valve comprising a plug having a first position blocking an aperture in the chamber, the plug being biased towards the first position by a biasing force arranged such that an over-pressure within the container of less than the frictional fitting force causes the plug to move towards a second position away from the aperture so as to dissipate the over-pressure, the biasing force being operable to return the plug towards the first position upon a reduction of overpressure in the container.

The frictional fitting may include any type of fitting which allows the lid to be fitted by the simply application of a force towards the container (eg downwardly) and removed by applying an opposing force in a direction away from the container (ie upwardly), including a fitting using resilient elements such as flexible retaining members or clips engaging with a rim of the container.

According to a further aspect, the invention provides a lid for a container of a kitchen appliance, the lid having an access aperture for accessing the container with the lid attached, and a plug having a first position blocking the aperture and being biased towards the first position by a biasing force, and a second position away from the aperture so as to allow use of the aperture, the biasing force being arranged such that an over-pressure within the container causes the plug to move at least partially towards the second position so as to dissipate the over-pressure.

Thus the plug may serve the dual purposes of providing a removable cap for the aperture and providing an over-pressure release valve. Preferably the biasing force is arranged to return the plug to the first position upon a reduction in over-pressure.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

The invention also provides a computer program and a computer program product for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein, and a computer readable medium having stored thereon a program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein.

The invention also provides a signal embodying a computer program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein (e.g., as a file for use with a 3D printer to construct the apparatus and apparatus elements herein described), a method of transmitting such a signal, and a computer product having an operating system which supports a computer program for carrying out any of the methods described herein and/or for embodying any of the apparatus features described herein. The invention also encompasses a kit of parts for constructing any of the apparatuses or apparatus elements herein described.

Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination, in particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or a!i features in any other aspect, in any appropriate combination.

!t should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.

In this specification the word Or' can be interpreted in the exclusive or inclusive sense unless stated otherwise.

Furthermore, features implemented in hardware may generally be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly. Brief Description of Drawings

One or more embodiments will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which:

Fig. 1 is a side-on view of a kitchen appliance according to a first aspect of the invention;

Fig. 2 is a cut-away side view of a plug of the kitchen appliance in a closed position;

Fig. 3 is a cut-away side view of a plug of the kitchen appliance in an open position;

Fig. 4 is a top-down view of a lid according to a second aspect of the invention;

Fig. 5 is a side-on cut-away view of a release valve of the lid of Fig. 4 in a closed position; and

Fig. 6 is a side-on cut-away view of a release valve of the lid of Fig. 4 in an open position,

Specific Description

Figs. 1 -3 show an example of a kitchen appliance 100 according to an aspect of the present invention. Kitchen appliance 100 has a base 101 having a motor 102 that drives a rotary tool 103 located within a container 108 to process food ingredients within the container 108. Container 108 is either integral to or removable from the base 101 , and has an opening at its upper end that is closed by removable lid 104. Removable lid 104 includes a central through-hole or aperture 109 defined through it from its upper surface to its lower surface to allow ingredients and tools to be inserted into the container whilst the lid 104 is attached. When located within the central through-hole 109, the central through-hole 109 of removable lid 104 is closed by removable filler cap or plug 105 that fits into and substantially seals the central through-hole 109 of the lid 10 to prevent the egress of ingredients and noise from within the container 108 to the outside environment.

Plug 105, lid 104, and container 108 are preferably relatively non-sound-transmissive and/or sound-attentuafing in construction. Their construction may be such that a sound level of 80 dB(A) or less, or more preferably a sound level of 85 dB(A) or less, or more preferably still a sound level of 95 dB(A) is attenuated to 79 dB(A) or less, or more preferably 60 dB(A) or less (the approximate level of human speech at a distance of -1 metre), and even more preferably 50 dB(A) or less (the approximate ambient noise level in an urban environment). For example, they may be formed with one or more additional layers between their upper and lower surfaces so as to create multiple solid-air interfaces, include porous and bubble-filled elements such as foam, include vacuum- gaps in their construction, and be shaped so as to reflect and/or baffle sound directed from beneath so as to attenuate it. Moreover they may be partly or wholly formed of a viscoelastic, lossy material such as a polymer such as polyurethane.

The lid and/or the valve may be at least in part of liquid-tight, water resistant, and/or non- permeable construction. Alternatively they may be at least partly formed of sound insulation material which may be water-permeable, such as foamed urea-formaldehyde resin, polyurethane foam, or non-rigid PVC foam, with a water-resistant or non- permeable coating or shell. Preferably the lid and/or the valve comprise a food-safe, dishwasher-safe material such as TPE, polyurethane, vinyl acetate copolymer, polyethylene, polyamide, a PTFE such as Teflon(TM) , nylon, a poiyacetate and acrylonifriie butadiene styrene blend such as Terblend(TM) , and PVC.

The valve may be formed at least in part of a transparent material, for example a transparent copolmer such a Tritan(TM). Plug 105 is attached to arm 107, which in turn is attached to the lid 104 by hinge 106. When the user wishes to remove the plug 105 from the central aperture 109 of the lid 104, they need merely pull it upwards so as to swing it away from the aperture 109 as shown in Fig, 3. When removed from the aperture 109, plug 105 remains attached to the lid 104, meaning that scales within the base 101 will not measure a reduction in weight, thus avoiding the need to re-calibrate the scale by e.g. taring by pressing a tare button on the base 101 .

Plug 105 is preferably weighted such that, for any significant over-pressure beneath it created by operation of the rotary tool 103 or a heating element of the base 101 that risks removing the lid 104 from the container 108, it will be lifted out of the central aperture 109 by the pressure beneath it, thus releasing the over-pressure. However the plug will remain normally closed in the absence of overpressure, or when the overpressure is not significant or sufficient to dislodge or lift the lid.

For example for a blender of typical dimensions, such as the Kenwood Blend-X™ blender, the plug 105 may be approximately 20-100 grams, and the arm 107 may be of weight and dimensions so as to add no more than 1 Newton of additional downward force, leading to a total downward retaining force acting on the plug of at most 2 Newtons, and preferably 1 Newton or less. Typically a blender plug is approximately 4 and 8 centimetres in diameter, and in the case of the Kenwood Blend-X™ blender is approximately 5.5 centimetres in diameter, meaning that an over-pressure of approximately less than 400 Newtons/metre 2 (N/m 2 ), and more preferably less than 105 N/m 2 , and still more preferably an over-pressure of less than 50 N/m 2 acting upwardly on the plug 105 is needed to over-come the downwards force on it. This avoids the development of the 280-500 N/m 2 over-pressures required to remove a typical frictionally-fitted blender lid within the container 108.

Of course, different dimensions, plug sizes, and retaining forces may be selected that may also achieve the desired goal of safely releasing over-pressures formed within the container and not allowing pressure to build up to an amount significantly in excess of atmospheric pressure such as might be found in a pressure cooker. Preferably the plug should release over-pressures of 5000 N/m 2 (for the toughest-to-remove lids) or more preferably 500 N/m 2 or less (for a typical lid), or more preferably still 280 N/m 2 or less (for an easier-to remove lid), or 50 N/m 2 (for the easiest to remove lids) whilst blocking the emission of significant sound-levels when not releasing over-pressures generated within the container.

Where the over-pressure is a temporary one caused by, e.g., the starting of the rotary tool 103 causing material within the container 108 to suddenly move upward in the container 108, once the over-pressure is relieved the plug 105 falls back into the central aperture 109 of the lid 104 under the influence of gravity, thus sealing the central aperture 104 again. Where the over-pressure is non-temporary (e.g., one caused by continual conversion of water to steam by a heating element within the container 108) the plug 105 will regularly rise out of the central aperture 109 to relieve pressure and then fail back into it.

In some embodiments, however, the arm 107 may be omitted and the plug 105 will merely rise and fall into and out of the aperture 109 to release over-pressures. Guiding posts may be included on the lid around the aperture 109 to keep the plug 105 correctly positioned and oriented as it does so.

Particularly, but not exclusively, where only temporary over-pressures are expected beneath/proximate to the lid that are balanced by under-pressures created elsewhere within the container 108 such as occur during the initial upward and downward surge of working medium when high-speed processing is initiated within a blender, the plug 105 may rise within a hollow column in sealing contact with the inside of it without releasing any over-pressure outside the container. In this configuration, the rising of the plug 105 creates additional volume within which the over-pressure can be dissipated, and once the pressure within the container 108 returns to equilibrium the plug 105 fails back down the column.

An alternative embodiment is shown in Figs. 4-6. Fig. 4 shows a lid for a kitchen appliance 200 which has a hinged plug 201 removably fitted in a central aperture. The hinged plug 201 in turn has a release valve 202 formed in a central aperture thereof.

Fig. 5 shows the release valve 202 in a closed position. In this configuration an expansion plug 203 which generally narrows in diameter towards a lower end thereof is downwardly biased by a helical spring 204 so as to be pushed far enough info the central aperture to close the central aperture of the hinged plug 201 . Whilst a helical spring is used here for exemplary purposes, any other suitably resilient biasing mechanism may be used, including leaf-springs, pneumatic pistons, and other biasing mechanisms, or the expansion plug 203 itself can be of sufficient weight that it is ordinarily held in place except where an over-pressure forms beneath it. The biasing force of the helical spring should be such that, for any given expansion plug 203, the total biasing force (i.e., also including gravitational biasing force, if any) biasing the expansion plug towards the aperture does not exceed the force that a pressure inside the container 108 of 280-500 N/m 2 sufficient to remove a typical frictionaily-fitted blender lid, or at least the -5000 N/m 2 required to remove the most difficult to remove lids, may apply to the plug 203 to push it away from the aperture. Dangerous over-pressures are thus dissipated.

Fig. 6 shows the release valve 202 in an opened positon. In this configuration the expansion plug 203 has be pushed upwardly against the spring so as to create an air- gap around its circumference between itself and the central aperture of the hinged plug 201 , thus allowing the over-pressure beneath it to escape. Stopping protrusions 205 formed near the lower extremity of the expansion plug 203 stop it from being expelled completely out of the central aperture of the hinged plug 201 as they come into contact with the hinged plug 201 if the expansion plug 203 rises too high. Stopping protrusions 205 can have through holes formed between them or through them to allow overpressure to continue to escape when the expansion plug 203 is forced upwards against the hinged plug 201 . Whilst release valve 202 is shown formed in the hinged plug 201 for exemplary purposes, it may be formed anywhere in the lid 200 or even on the container to which it is to be attached. Release valve 202 may include a shell 206 surrounding the expansion plug 203 to block the expulsion of working-matter from within the container 108 when expansion plug 203 is in an open position, shell 206 may have baffled through-holes formed in it to permit the emission of over-pressure through it whilst blocking working- medium.

Whilst a roughly frusto-conicai plug 203 is used here for exemplary purposes, the plug 203 may instead be cylindrical or of another shape such that it fits into and seals the aperture unless pressure is applied to it that expels it. A cylindrical plug may be biased so thai at equilibrium it seals the aperture but if pressure is applied to it from either inside or outside the container it may move to relieve that pressure, thus making the valve 202 a two-way valve. Plug 105, hinged plug 201 , lids 104 and 200, and release valve 202 may be either electronically or mechanically interlocked with the motor 102 or a heating element of the kitchen appliance 100 designed to heat material within the container 108. For example either or both of their presence near the kitchen appliance 100 and their being fitted to the container 108 may be detected by a mechanical push-rod being pushed down to allow electric current to flow to the motor 102.

In a more advanced configuration, the base 101 houses a PCB that is in electronic communication with presence sensors and the motor 102 such that it can receive sensor information and control the motor 102 and a heating element of the kitchen appliance 100 based on the presence information received from the presence sensors. Since the release valve 202 and hinged plugs 105 and 201 may be temporarily in an open position, the PCB may contain a program within its memory with instructions to apply a wait-time between detecting an absence of a required element via data transmitted from the sensors, and controlling the motor 102 to reduce speed or cease operating, and if the presence information returns to its previous status not controlling the motor 102. This wait-time can be enough to allow a temporary emission of over-pressure from within the container 108 (e.g., 0.5-5 seconds) or long enough to allow the insertion of ingredients into the container 108 (5-30 seconds). The PCB may display status information including feedback from the presence sensors in a user interface of the base 101 . Telemetry from the sensors may be communicated to a cloud outside the kitchen appliance 100 by a wireless adapter of the PCB.

The PCB may also be in electronic communication with the scales of the base 101 , and automatically re-calibrate them, or data received from them to be displayed on a user interface, based on presence information received from the sensors so as to compensate for elements such as the plugs 105 and 201 not being attached to the lids 104 and 300, or the lids 104 and 200 not being attached to the container 108. For example, the PCB may include various weights of components within its memory, and automatically add the weight of a missing component to the weight detected by the scales to compensate for it not being attached to the machine. Terms like "electronic communication", "data transmission" as used herein can include all forms of electronic communication including data-transmission and powering-on/off. digital or analogue, wireless or wired, or any suitable combination of these. This includes WiFi Zigbee, Bluetooth, RFID, NFC, other radio-frequency transmission means, parallel or serial bus communication, and other communication means. Furthermore it includes data-transmission even where mediated partly or wholly through non-electronic forms including fibre-optic, laser, sonic, infra-red, mechanical etc. Where one element of the invention disclosed herein is shown or described (either implicitly or explicitly) as being electronically inter-networked with others (i.e., connected to another element that is connected to one or more further elements), this should be read as including the possibility of communication of data and instructions between any one of the elements and any other of the elements with which it is inter-networked unless otherwise stated. Clouds, servers, processors, user interfaces, sensors, memories, routers, adapters, and other electronic elements should all be considered as including processors, and/or data-transmission/storage suitable for their described tasks.

The invention may take a form different to that specifically described above.

Where blending is used as an example of a food processing activity above, other food processing activities can be carried out including beating, whisking, mixing, folding, stirring etc. with suitable tools. Where a bottom-driven food processing machine (e.g., a blender) is used as an example, it may instead be implemented in a top-driven food processing machine (e.g., a stand-mixer or kitchen machine), or indeed in a machine where the rotary tool is initially oriented horizontally or at another angle. Whilst table-top domestic food processing machines have been used as an example implementation, the invention may also be implemented in a hand-held tool such as a hand-blender or hand-blender attachment. The term "kitchen appliance" encompasses all such devices.

Whilst the invention has been described in the field of domestic food processing and preparation machines, 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. Mechanical and other improvements disclosed herein may find application in automotive and industrial fields, the field of tools including hand-tools, the plumbing field, the field of hydraulics, and are not limited in application to kitchen appliances.

The invention described here may be used in any kitchen appliance and/or as a standalone device. This includes any domestic food-processing and/or preparation machine, including both top-driven machines (e.g., stand-mixers) and bottom-driven machines (e.g., food processors). It may be implemented in heated and/or cooled machines. The invention may also be implemented in both hand-held {e.g., hand blenders) and table-top (e.g., blenders) machines. It may be used in a machine that is built-in to a work-top or work surface, or in a stand-alone device. The invention can also be implemented as a stand-alone device, whether motor-driven or manually powered. Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

It will be understood that the 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 any claims are by way of illustration only and shall have no limiting effect on the scope of the claims.