GB2482321A

GB2482321A - Heat Insulation Arrangement for Cookers or Stoves

Info

Publication number: GB2482321A
Application number: GB1012741.3A
Authority: GB
Inventors: Graham Hodgson
Original assignee: NOVEL ENERGY Ltd
Current assignee: NOVEL ENERGY Ltd
Priority date: 2010-07-29
Filing date: 2010-07-29
Publication date: 2012-02-01
Also published as: GB201012741D0

Abstract

A factory fitable or user retrofitable system for controlling the level of waste heat emissions from a cooker, in particular a heat storage or radiant heat cooker (or stove), by way of a plurality of user mountable and demountable heat insulation devices. The said cooker heat-insulation device comprises a composite structure of glass, ceramic, and metal layered materials, and is shaped to match a particular cooking surface. The device is arranged to be located in proximity to a cooking surface of a cooker to receive heat therefrom at one side and to provide heat insulation at another side opposite the said one side, the device further including an engagement formation for readily moving the device into, and out of, an operative position with respect of the said cooking surface. The device 12 can be readily arranged for employment in relation to a hob-plate and common hob lid 10 and secured by material ties 16, 18. An alternative embodiment may be arranged for use in association with an oven door of a heat storage or radiant heat cooker for controlling the waste heat emissions from those regions.

Description

The present invention relates to a heat insulation device particularly for use in controlling waste heat emissions from cookers (or stoves) into a room.

The present invention finds particular use when employed in relation to a cooker (or stove) employing radiant heat, often referred to as a heat storage cooker.

In particular, the invention relates to domestic cookers (or stoves), of which there are two main types, and as noted it can apply specifically to the second type outlined below and which employs radiant heat.

The most common type of domestic cooker (or stove), is based on the principle of cooking by direct convective heat from proximal heating elements, and generally referred to as a standard cooker. Oven compartments are made from pressed steel, and incorporate exposed heating elements (typically natural gas or electrically powered) located within the walls of the oven compartment with or without further concealed elements. When placed into the compartment, food is cooked through convection, using air that is heated by the high temperature elements. Fans are often provided in such ovens for speed and evenness of cooking. These ovens are turned off when not in use and take a short time, usually about 10 minutes, to warm up when required for cooking. They have a low thermal mass. Such cookers often incorporate natural gas or electrically powered direct heating elements such as bobs, located on or within the top surface of the cooker, which cook by direct heat transfer. These hobs are turned off when not in use and take a short time, usually about one minute to warm up when they are required for cooking.

Another, although less common type of domestic cooker, based on the principle of cooking by radiant heat, using heat stored within a thermally insulated heavy cast iron body, and generally referred to as a heat storage cooker. This type of cooker generally has multiple oven compartments, and is typified by the well known Aga® brand. Each oven compartment is slowly heated over a long period, generally in the order of six hours or so, via thermal communication through a system of ducts from a typically oil or natural gas fired or electric heat source located centrally within the cooker but outside the walls of each oven compartment. The walls of each oven compartment are formed from cast iron usually in the order of 5 -10 mm thick. This is not only heavy but also has a high thermal mass. These ovens are not turned off between uses but run continuously so that they are always ready for immediate use. During cooking, heat stored in the cast iron walls of the oven compartments is radiated into the food. These ovens run at a constant temperature, maintained by thermostatic control of heat source. Such cookers also often incorporate hobs located on or within the top surface of the cooker, which are heated via ducts from the same central heat source. As with the ovens, they are not turned off between uses but run continuously so that they are always ready for immediate use. Such hobs are often provided with hinged lids which seek to contain the heat in a similar way to an oven door.

Such heat storage cookers do not have any powered heating elements within the walls of the oven compartment or on the hob. Rather they operate by radiation of heat stored in the oven compartment walls or hob plate, both of which have received heat via ducting from a central heating element located outside the oven or hob plate. The cooking process for cookers of this type is quite different from cookers in which a heating element is located within the oven compartment. Rather than heating food convectively from proximal heating elements, the ovens radiate heat evenly from each of their five walls.

Typically food cooked in this way is less prone to burning, retains much more moisture, and cooks more quickly.

When the heat storage cooker was first invented in 1922, it was lauded for its energy efficiency, being more efficient than alternatives of the day such as an open fire or standard coke stove. However, the fundamental design concept has changed little since then, and by comparison to today's modern cookers is considered by many to be an energy inefficient way to cook food. Criticism of the environmental credentials of heat storage cookers arises because they only work properly if they're turned on all the time, a requirement which contradicts modem views on the need for energy conservation.

For comparison, an average standard type electrical cooker and hob consumes 5 11kW during a year (according to UK company, Carbon Footprint Ltd) which is just 4.4% of the 11.65MW energy (according to UK company, Aga Rangemaster Ltd) used by an average two oven heat storage electric cooker during a year. Also, the energy consumption disparity is even greater for other fuel types, e.g. natural gas, where a standard type cooker consumes just 2.7% of the energy of a heat storage cooker. The carbon emissions for a standard type electric cooker are approximately 0.28 metric tonnes (MT) of carbon dioxide (CU2) per year, whereas the carbon emissions of such a heat storage electric cooker are approximately 6.34MT/yr of CO2 which is greater than the average emission for an entire British household (5.SMT/yr according to the UK Energy Saving Trust) and twice the UK government target for individual houses by 2020.

Of course, the cost of running heat storage cookers increases as energy costs increase, due to constraints in the supply o f mineral-based fuels, and government taxes on the carbon content of such fuels. This becomes a significant problem for users of heat storage cookers, since the fuel cost of running a two oven electric heat storage cooker rises by £23 for every £1 it rises for a standard type electric cooker.

By their very nature, heat storage cookers exhibit high energy consumption in order to heat and maintain the temperature oftheir large and heavy cast iron construction and high thermal masses. Energy input is required continuously, even when not cooking, since the cookers are designed to remain on when not in use. Due to the disadvantageously limited nature of the internal insulation and various thermal bridging design problems, when the cooker is idle, much of the input energy is wasted as thermal radiation and convection from the cast iron structure, oven doors, and hob lids into the kitchen and flue extract, and by conduction into the floor and adjacent walls or cupboards. This in turn heats the kitchen where the cooker is located.

Many users enjoy the heat radiated by the cooker into the kitchen, which becomes an attractive feature on cold winter days. Conversely, users can also find that the heat is uncomfortable during the summer and periods of hotter weather. There are few viable factory fitable or user retrofitable solutions that allow users to control the level of waste heat emissions into the kitchen. Any modifications that affected the aesthetics of the cooker would not be acceptable to most users, who place great stock in the traditional and homely look and feel of these cookers, and regard them as status symbols. Various attempts have been made to address the issue, but most are very dissatisfactory: Since waste heat emissions cannot currently be controlled, many users resort to turning the cooker off in hotter weather, and using alternative cooking devices. They will often buy small stand-alone hobs, grills, and kettles specially to use in summer. Some manufacturers sell ancillaiy, type one, electric cookers in the same aesthetic design to sit alongside the heat storage cooker for use in summer, an example of which is the Aga ® Companion Module. The heat storage cooker is thus unavailable for cooking; and money is inefficiently spent on substitute cooking devices which also take up extra space and spoil the desired kitchen aesthetic. Other manufacturers have developed type two heat storage cookers that double as type one cookers by incoiporating a fan assisted electric oven compartment and gas or electric hobs into the cooker, allowing the central burner to be switched off in summer, an example of which is the Redfyre ® Universal Range.

Alternatively, some users resort to reducing the cooker thermostat setting to reduce the cooker temperature. This reduces the amount of heat leakage into the room, hut also reduces cooker functionality and diminishes usability for cooking food. Some manufacturers have developed timer devices to control the burner settings and turn such settings down during nights and other periods of inactivity. Examples of which are patent applications GB 2 463 014 A and GB 2 447 777 A, the latter of which discloses a so-called Intelligent Management System (AIMS). However, this has the disadvantage that in order to set the timer device, users must plan ahead for when they want to use the cooker, since the cooker may be in turn-down mode and not ready and available to cook when they need it, which defeats the purpose of an always-on cooker.

Attempts have also been made to remove the factory fitted insulation from inside the cooker in the spaces between the ovens, hot plates and burner, and replace inside with uprated high grade insulation (such as Rockwool, Microtherm® free flow granules, Aspen Aerogels® , or Thermal Ceramics® materials etc.). This can be extremely expensive, and once filled, it is impractical to revert to original insulation in winter or on cold days, so the cooker is permanently cooler. Such a retrofit requires taking the oven apart which is major undertaking, and might invalidate manufacturer's wananty Further, it has been suggested to insulate the full outer surface of the cooker. However, this is expensive and impractical because oven doors and hob lids need to be readily accessible, rear and side surfaces are difficult to access, and it is likely to destroy the cooker aesthetics that are considered important to users, Most importantly it could lead to destabilisation ofoven temperatures relative to each other, or even convergence in oven temperatures, where all oven compartments become the same temperature, which would eliminate the fundamental radiant heat cooking functionality whereby food is moved between oven compartments of different temperatures during the cooking process.

Also, while specific parts of the external cooker surface could be insulated the temperature of the surface under the insulation will increase, causing the temperature of the non-insulated interconnected surfaces to increase due to thermal flux (Le Chatelier's Principle), rendering the insulation less effective.

The present invention therefore seeks to provide for means to control the waste heat emissions of cookers, and in particular heat storage cookers, into a room, and in particular to thereby improve energy consumption and reduce CO2 emissions. in particular the invention seeks to provide for a system of factory fitable or user retrofitable heat insulation devices for cookers. Moreover, the invention seeks to provide a user friendly mountable and demountable heat insulation device that is located directly at the cooking surface, in a manner that is aesthetically unobtrusive, and generally does not interfere with the appliance's cooking functionality or characteristics.

According to the present invention there is provided a cooker heat-insulation devicegenerally comprising a composite structure of glass, ceramic, and metal materials shaped to match a particular cooking surface. This composite insulation package (CIP) device is advantageously arranged to be located in proximity to a cooking surface of a cooker to receive heat therefrom at one side and to provide heat insulation at another side opposite the said one side, the device further including an engagement fbrmation for readily moving the device into, and out of, an operative position with respect of the said cooking surface.

The device can comprise a fabric pad of heat insulating material.

The invention is advantageous in providing improved heat insulation for cookers in an unobtrusive, simple, cost effective, and factory fitable or user retrofitable manner having no impact on the cookers functionality.

Preferably, the said CIP device comprises a layered structure.

Further, the said device can be formed of one or more of a layer of glass-fibre, silica, or ceramic based textile; stiffening structures; and one or more of a layer of a low thermal conductivity insulation material in blanket, granule or board form.

With regard to opposite outer layers of the device, they can be formed of glass-fibre, silica or ceramic based textile.

In a preferred structure the said outer layers can be arranged to encapsulate layers of low thermal conductivity insulation material.

In one embodiment, the device can be arranged to be located in proximity to a bob-plate ofthe cooker.

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In particular, the shape of the said device can conform to that of the said hob-plate.

As a further advantage, the said engagement formation includes means for attachment of the device to a hob-plate lid of the cooker.

In this manner, the means for attachment can comprise means for attachment to the handle and/or hinge of the said hob-plate lid.

Such means for attachment can comprise any appropriate means given the shape and configuration of the lid and its features. Means that are releasably secured are preferred and can comprise, for example, releasable press-fit formations, Alternatively, or in addition the means for attachment can comprise flexible ties such as ties formed from glass-fibre, silica, or ceramic based textiles.

To assist with ready manipulation and movement of the device a handle portion can be provided on the said another side ofthe device.

As a further example, the said device can be arranged to be located in proximity to an opening of an oven compartment of the cooker.

Advantageously, the device can be arranged to be received in the said opening and to allow closure of the compartment by way of an oven door, while operatively in situ.

Preferably, the said device can include a flange portion, which can extend substantially around the whole perimeter of the device.

The said flange portion can comprise heat insulating material.

In a preferred configuration, the outer dimensions of the device as defined by the flange portion can be arranged to correspond to an inner cross section of the oven compartment.

The said flange portion can therefore provide means by which the device is located in the oven.

Advantageously therefore, the said flange portion can be flexible, which may also allow it to be locatable through oven openings that may be smaller than the inner cross section ofthe oven compartment.

Further, the said flange portion can be resiliently deformable and, in particular, can exhibit a temperaturedependent resilience, such that it remains flexible at ambient temperatures and adequately seals the opening at temperatures up to at least 320°C. I ()

As a hirther feature, at least the flange of the device can include a shape memoiy alloy support structure.

As with the bob-plate example, this frirther version of the device can include a handle provided on the said another side of the device.

As will be appreciated, the said CIP device can be ananged to exhibit at least some degree of resilience, such as a temperature dependent resilience, and/or that provided by a super-memory material.

As will therefore be appreciated, the invention addresses the aforementioned problems by providing a means to control the waste heat emissions of cookers and in particular, heat storage cookers. The invention provides for a system of factory fitable or user retrofitable CIP devices for cookers that can be readily mounted or demounted by the user to control level of heat emission into the kitchen or reduce energy consumption. Advantageously, the invention provides a targeted insulation solution directly at the cooking surface rather than the previously mentioned (but less effective or less practical) approaches. When installed, the invention is not clearly visible to the user, and thus does not detract from the aesthetics of the cooker, and generally does not interfere with the appliance's cooking functionality or characteristics. Furthermore, as waste heat emission is reduced, the cooker energy consumption reduces, allowing users to save on hid running costs. As the fuel consumption reduces, so the levels of CO2 emission to atmosphere reduce, making the cooker more environmentally friendly.

The invention incorporates high technology materials, yet can retain a user-friendly look and feel. As noted the invention can be readily incorporated into the hob lid and oven door regions of heat storage cookers.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic view of the manner of mounting and the use of an embodiment of the present invention in association with a hob plate and lid; Fig. 2 is a plan view of an initial layered element forming a device according to an embodiment of the present invention; Fig. 3 is a plan view of a further layer for incorporation within the embodiment of the present invention of Fig 1; Fig. 4 is a plan view of a final layer for encapsulation within the embodiment of the present invention of Fig 1, including a handle portion for ease of manipulation and movement, and ties for connection to hob lid;; Fig. 5 schematic side view of the layered device from the elements of Figs 2 4; Fig. 6A and 6B are plan & side views of initial layers forming an insulating device according to another embodiment of the present invention; Figs. 7A and 7B are plan & side views of an intermediate rigidity layer structure employing the initial layer of Fig. 6; Figs 8A and 8B comprise plan and side views respectively of the embodiment of Fig. 6 with a further layer included; Figs 9A and 9B comprise plan and side views respectively of the structure of Figs 8A and 8B but with a further encapsulated layer added; Figs lOA and lOB comprise plan and side views respectively of the final encapsulated structure including a handle portion for ease of manipulation and movement; Fig 11 is an exploded view of another embodiment of the invention; Fig 12 is an illustration of the manner of use of the device of Fig 11; Fig 13 is an exploded view of yet a further embodiment ofthe invention; and Figs 14A and 14B are illustrations of the manner of use of the embodiment of Fig 13.

As will be appreciated most heat storage cooker hob plates are covered by a hinged swing-back cast iron hob lid, which can be circular or rectangular in cross section and is often domed for aesthetic reasons, with a convex dished underside. The lid may incorporate different metals above the cast iron base, and the dome section above the convex dish may incorporate insulation materials. Thermal bridging within the hob lid design where different metal components are coimected causes much of the heat from the hob plate to conduct to the entire hob lid, despite any insulation that may exist in the dome section, resulting in radiated and convective heat (and energy) loss into the kitchen.

The invention can advantageously address the problems associated with thermal bridging within the bob lid design by minimising thermal conduction between hob plate and bob (3 lid. Thus heat, and energy transfer to the hob lid is minimised, which in turn minimises heat leakage and energy waste into the kitchen.

The illustrated embodiment of the invention discussed below in association with Figs. 1 to 5 can employ a CIP device designed to fit the underside of a (typically circular or rectangular) hob lid, extending to cover the entire underside surface, thus providing a barrier between the hob plate and hob lid.

Fig. 1 is a schematic view of such an arrangement showing a common hob lid 10 and a CIP device 12 of the present invention having material ties 16, 18 for releasably securing the device to the handle and hinge of the lid 10.

It should however be appreciated that various forms of construction can be employed and the following is merely an example.

User-friendly outer layer of high temperature, flexible, stitchable, smooth woven, non toxic, glass-fibre, silica, or ceramic based textile, rated for 0°C to at least 500°C is first provided. This contains minimal organic or binder content, and can be pre-heated, or caramelised, to avoid ffiming or gassing when placed on hot plate. This layer can further include heat rated abrasion resistant coating formula to reduce wear and tear damage from rough charcoal deposits on the hot plate. It is also advantageously arranged not to scorch nor discolour significantly in use, Further, it can be shaped and stitched to frilly encapsulate insulation materials as discussed below and may also encapsulate stiffening structure.

A stiffening structure such as metal mesh or plate, ceramic, or some other rigid, heat compatible material, rated for 0°C to at least 5 00°C with good mechanical strength, crack resistant under thermal shock conditions, without potential to rust or corrode can be included to provide rigidity and form to the device. This structure may be encapsulated within the high temperature textile noted above.

Layers ofveiy low thermal conductivity insulation materials such as silica-based nano-porous Aero gels, or similar, in blanket, and or granule, and or board form, rated for 0°C to at least 500°C are provided. This material contains minimal organic or binder content, to avoid fuming or gassing when placed on hot plate and can be encapsulated within the above textile.

An attachment mechanism is provided to temporarily attach the device to the underside of hob lid, provided for quick and easy release, such as magnets, screws, ties, linkages, or other material, rated for 0°C to at least 500°C. Possibly incorporating metal arms shaped to follow the inner contour of, and mate with, the hob lid handle or hinge.

A handle arrangement can be provided, formed from a high temperature textile such as that noted above and attached on the upper surface of the device to allow easy and safe removal when unattached from hob lid, even when the device is hot.

Turning therefore to Figs. 2-5 as further illustration of structural details of an embodiment of a hob-plate version of the present invention. With regard to Fig. 2, there is illustrated a base layer disk of high temperature, caramelised glass cloth 24, upon which sits a smaller diameter disk of 5mm thick Pyrogel Aerogel insulation 25, and upon that a stainless steel mesh 26 providing rigidity and being convex in profile, being secured by way of spot stitches 27 to the Pyrogel layer 25.

A further layer of structure is provided as illustrated in Fig. 3 by addition of a even smaller diameter disk of 5mm thick Pyrogel Aerogel insulation 28, which is stitched by means of high temperature glass-fibre yarn 29 to the 5mm Pyrogel layer 25.

Fig. 4 illustrates the addition of a final encapsulating layer disk of high temperature, caramelised glass cloth 30. If required, and as illustrated in this example, an excess outer perimeter of the base layer 24 can be folded over the perimeter regions of the top layer 30 and stitched around the circumference to encapsulate the contents. Fig. 4 also shows textile handles 32 which can be attached to the layer 30. Respective handle ties 16 and hinge ties 18 can be connected to the bottom of layer 24 and, in this example, comprise black silicone-coated caramelised glass cloth loop-ties.

Fig. 5 provides a schematic side view of the various layers of the device structure of the illustrated embodiment of Figs. 1 and 4 and from which the encapsulation of the Pyrogel insulation layers 25 and 27, and stainless steel mesh 26, by means of the layers 24 and 30 is clearly visible.

Of course a separate Hob Lid device may be installed on each hob lid on a single cooker.

A second example of an insulating device according to an embodiment of the present invention relates to a CIP device arranged for use in association with an oven door.

A typical oven door design includes a layer of insulation at the rear, which is captured and encapsulated within a rectangular metal cover, which in turn is screwed tightly onto the rear of the door by means of metal screws. This in turn acts as a thermal bridge, allowing heat from the oven compartment behind to conduct to the front of the oven door, allowing heat, and energy, from the oven to emit into the kitchen. Furthermore there is a region around the inside of the oven door which necessarily contains no insulation, to allow the door to readily open and close, and which provides a path for heat to conduct out of the oven to the front of the door and into the kitchen. A minimal heat seal is provided by thermal rope.

In general, there exists a short section of spacer ducting directly behind the oven door of a typical heat storage cooker where the cast iron fascia of the cooker frontage, to which the oven door attaches, is separated from the set back entrance of the oven compartment.

This ducting section is usually sealed at either side by means of circumferential thermal rope. The depth of this spacer ducting section is typically around 30mm. The oven door and cooker fascia are therefore somewhat thermally decoupled from the oven compartment but only to a disadvantageously limited extent.

This embodiment of the invention can be employed to address problems associated with thermal bridging and heat leak paths within the oven door design by minimising advantageously thermal conduction between the oven compartment and the inside of the oven door. This embodiment can take advantage of the thermally decoupled fascia section behind the door. Thus the heat and energy transfer to the oven door is minimised, which in turn minimises heat leakage and energy waste into the kitchen.

As will be appreciated, it can comprise a rectangular shaped CIP device arranged to be inserted inside the typically 30mm deep thermally decoupled spacer ducting section behind the oven door, which separates the cooker fascia from the oven compartment. By means of a flange region, the device can extend to cover the entire oven spacer ducting cross section, thus providing a barrier between oven compartment and oven door.

As a particular example, the structure can comprise a user-friendly outer layer of high temperature, flexible, stitchable, smooth woven, non-toxic, glass-fibre, silica, or ceramic based textile, rated for 0°C to at least 3 20°C. Again it contains minimal organic or binder content, and can be pre-heated, or caramelised, to avoid fuming or gassing when placed in oven. A heat rated abrasion-resistant coating formula can be incorporated to reduce wear and tear damage from insertion and removal from oven structure. As with the hob version, this layer is arranged not to scorch or discolour significantly in use. Further it 1$ can be shaped and stitched to fully encapsulate stiffening structure, insulation materials, and expansion mechanism.

Next, layers of very low thermal conductivity insulation materials such as silica-based nano-porous Aerogels, or similar, in blanket, and or granule, and or board form, rated for 0°C to at least 320°C are provided. These contain minimal organic or binder content, to avoid fuming or gassing when placed in oven. These layers are arranged within the high temperature textile layer above.

An optional stiffening structure such as metal mesh, ceramic or fibre board, or some other heat compatible material, rated for 0°C to at least 320°C with good mechanical strength, crack resistant under thermal shock conditions, without potential to rust or corrode, to provide rigidity and form to baffle. If incorporated, this structure may be encapsulated within the high temperature textile layer above.

The further particulars of such example are illustrated with reference to Figs. 6-10.

Fig. 6 illustrates the initial rectangular layer 34 of high temperature silicone and PTFE coated glass cloth 34 and which is arranged to be larger than the oven compartment cross-section, so as to allow formation of the flange member around the perimeter thereof. Next a layer of 5mm thick Pyrogel Aerogel insulation 36 sits on top of 34 and is stitched in place around its perimeter using high temperature glass-fibre yarn 37.

Fig. 7A and 7B comprise plan and side views of the developing structure and in which a rectangle of stainless steel mesh 38 is positioned on top of layer 36.

The structure is further developed as illustrated in Figs. 8A and 8B in which a relatively thick, and perhaps double, layer of binderless inorganic flexible Superwool layer 39 is, for example, stitched to the blanket layer 36 and which has dimensions allowing for, ideally, a 20 mm clearance with the oven aperture so as to allow for ease of insertion and location therein. The thickness of the Superwool layer 39 is generally in the order of 20-mm so as to match the aforementioned depth of the point of interface between the oven facia and the inner oven compartment.

Subsequent encapsulation of the Superwool layer 39 is illustrated with reference to Figs. 9A and 9B through the addition of a layer ofhigh temperature silicone and PTFE coated glass cloth 40 over the Superwall layer 39 and in the manner such that the heat rated fabric 40 extends to present side regions 42 so as to fully encapsulate the Superwall layer 39 as illustrated particularly in Fig. 9W The final structure is formed as illustrated with reference to Figs. IOA and lOB through the provision of folds in the perimeter region of the base layer 34 of Figs. 7A and 7B as illustrated with reference to arrows A of Fig. lOA so as to form the fully insulated flange regions 44 ofthe insulated pad device.

As will be appreciated, the flange regions 44 are preferably resiliently deformable so as to allow for accurate positioning, and retention, of the CIP device in its required position within the oven compartment opening.

Finally, a fabric handle 46 can be attached to the outer surface of the layer of heat rated fabric 40 so as to provide a handle by means of which the insulating device of this illustrated embodiment of the invention can be readily maneuvered into and out of, position even when hot.

Since the oven door opening may be smaller than the inside cross section of the oven spacer ducting and oven compartment, the embodiment include an expansion mechanism to increase the size of the device once inserted through the oven door opening, to fill the cross section of the oven spacer ducting completely to form a thermal hairier, yet allow ready insertion and removal of device. Such expansion can be achieved by use of circumferential frame of insulation material reinforced by shape memory alloy (for example titanium nickel which will retain its shape memory up to 400°C) which can be repeatedly compressed or bent by the user to insert (or remove) through the oven door opening, yet will revert to its original frame shape only at oven temperatures, to expand and seal the gap. Alternative methods might include, amongst others, use of a flexible outer circumrerential lip of insulating material, which acts as a gasket heat seal around the body of the baffle, or spring contraptions or carbon fibre based torsion bars which will compress on insertion and expand the device when in position. Again, this can all be encapsulated within the high temperature textile layer above.

Finally, a handle arrangement formed using high temperature textile and stitched on front side of the device body to allow easy and safe insertion and removal from oven, even when the device is hot.

Turning now to Fig 11, there is provided an exploded view of any hob insulating design 48 according to an embodiment of the present invention. This particular example of the invention includes two heat-treated glass cloth handles 50 attached to a disk of heat-treated glass cloth 52 covering any disc 54 of high temperature ceramic Aerogel insulation attached in turn to a larger lower insulation disc 56 also of high temperature ceramic Aerogel. This in turn is located on a base layer disc 58 of high temperature heat-treated glass cloth which is connected, by way of rivets 60 to a pressed aluminium disk 62 having a dish profile and arranged for the connection of a pair of metal arms 64.

Fig 12 illustrates the manner of use of insulating device 48 of Fig 11 and, in particular, its proposed mounting in relation to a cooker body 66 presenting a hot plate (hob) 68 and associated hob lid 70. The hob lid includes the usual hinge 72 and handle 74 and while the material ties of the device 48 illustrated in Fig 12, and the pair of arms 64, are provided for secure connection to the hinge 72 and handle 74 respectively, secure connection of the device 48 in relation to the lid 70 and, importantly, the hot plate 68 can be achieved in any advantageous and simple manner.

Turning now to Fig 13, there is provided an exploded view of an insulating device 76 according to yet another embodiment of the present invention. As will be appreciated, this embodiment is arranged for use in relation to an oven compartment as is illustrated further with reference to Figs 14A and 14B.

The family structure of the device 76 of Fig. 13 comprises a base sheet of silicone and PTFE coated high temperature and heat-treated glass cloth 78 to which is affixed a high temperature ceramic Aerogel insulation 80 bounded by a titanium nickel-based shape-memory alloy frame 82 to provide the shape-resilience discussed previously. Two layers 84, 86 of high temperature ceramic Aerogel insulation are then attached to each other and the blanket 80 prior to the addition of a covering layer of silicone and PTFE coated high temperature and heat treated glass cloth 88. As with the previous oven-compartment embodiment the bas layer 78 is arranged to be folded back as indicated by the arrows in Fig 13 and 2 handles of heatt-treated glass cloth 90, 92 are attached to the cover 88 as illustrated.

Figs 14A and 14B illustrating use of the device 76 of Fig 13 and in relation to a cooker oven compartment accessed by way of an opening in the oven fascia 94 and which can be shut by way of an oven door 96. The device 76 is arranged to be introduced to the oven compartment in the direction of the arrow in Fig 14A and so as to be mounted in the opening thereof as illustrated by the schematic plan view presented by Fig 14B. Here, the tight fit ofthe outer flange of the device 76 is clearly restricted in relation to the region between the fascia and the oven compartment 98, but can be compressed to fit in this embodiment by way of the shape-memory frame 82 of Fig 13.

Advantageously, the device 76 does not interfere with closure of the door 96 and presents a complete area of insulation to heat radiated from the oven compartment out towards the door.

Of course, a separate device may be inserted inside each oven of a multi-oven cooker.

Typically the device would be removed when cooking, and re-introduced when the oven is not in use.

The following are representative examples of the performance of embodiments of the invention.

Using a typical natural gas powered 3 oven heat storage cooker (Aga® cooker in this instance) as a test bed, devices were fashioned to test on the cooker to measure the extent of heat emission and energy reduction from the hob lids and oven doors.

The cooker was fitted with a dedicated gas flow meter to allow measurements of cooker fuel consumption during each test. With oven and hob temperatures constant, over a period of 104 hours the average gas fuel consumption for the cooker operating under normal conditions without any form of additional insulation was 20.69m3 of natural gas, which is equivalent to 2.23 5kw per hour.

First, the hobs were insulated with a system according to the present invention. One device was placed on each of the hob plates, and the hob lids were closed, to determine the possible energy savings. With hob temperatures constant, over a period of 8.4 hours the average fuel consumption for the cooker was 1.52m3 ofnatural gas, which is equivalent to 2.034kW per hour. Therefore devices on both hobs reduced energy consumption by 201W per hour. This equates to a CO2 emission reduction of 0.32MT/yr, or for an electrically powered version of the same cooker, a reduction of 0.96MT/yr.

Next, the ovens were insulated with a system according to the present invention. One device was placed in each of the three ovens in the thermally decoupled spacer ducting sections behind the doors, to determine the maximum possible energy savings. With the hob devices still in place from the previous test, and oven temperatures constant, over a subsequent period of 20.2 hours the average gas fuel consumption for the cooker was 2.99m3 of natural gas, which is equivalent to 1.665kW per hour. The contribution to reduction in energy consumption from the doors devices alone is thus 369W per hour.

The kitchen temperature dropped noticeably. This equates to a CO2 emission reduction of 0.59MT/yr, or for an electrically powered version of the same cooker, a reduction of 1.76MT/yr.

Savings Summary by Fuel Type:

Savings based on 3 oven Agu® heat storage cooker with three door and two hob devices ins ta lied Liiii nflinsEnthsiOfl Reduction Electricity *1 570W £465/yr 2.72MT/yr Natural Gas *2 570W £180/yr 0.92MT/yr Oil *3 570W £209/yr 1.33MT/yr * 1: Economy 7 EDF pricing ofE0. 1115/kW during day rate, and £0.0483 during night rate, June 2010 *2: Annualised gas unit price for London, EDF Energy including all tiers & discounts, June 2010 *3: UK ave oil unit price, as of 1 1-Mar-10 In operation, the user determines the desired amount of waste heat emission into the kitchen, by mounting such number of CIP devices that heat is abated to requirements.

The table below illustrates possible waste heat emission reduction (in watts) into kitchen as the system of CIP devices is step-wise mounted into a two hob, three oven heat storage cooker.

Waste heat emission Step-wise CIP Device Mounting reduction (in watts) Hot plate hob 143W As above plus Simmer plate hob 201W All the above plus Hot Oven 410W [JI the above plus Baking Oven 535W All the above plus Warming Oven 570W As can be appreciated, the devices can be mounted in various combinations whereby some but not all of the devices are mounted at any one time. On a two hob, three oven cooker for instance, this provides the user with 32 different levels of waste heat emission and energy reduction control.

As will be appreciated from the above discussion the present invention exhibits many advantages.

The CIP device is positioned directly at the cooking surface and removable when cooking. In the case of the hob device, being automatically removed when cooking by action of opening the hob lid. The device is readily installable and removable by the user quickly even when hot, with no special tools being required, does not affect functionality of cooker for cooking, unlike burner timer devices, and does not affect hob or oven temperature balance or create temperature convergence. It may reduce cooker energy consumption by at least 570W per hour; and thus reduce cooker fuel cost by least £465/yr, and CO2 emissions by at least 2.7MT/yr in the case of electric cooker. Further, the invention allows the user to control the level of waste heat emissions froin cooker into the room, e.g. in hotter weather, user can mount more devices to reduce kitchen temperature to personal taste, and so avoid the need to turn the cooker off. The invention can incorporate specially selected high temperature textiles to encapsulate insulation and body materials and contain any dust released from insulation, Preferably, it can incorporate specially selected high temperature low thermal conductivity insulation materials to ensure the invention thermally decouples the cooking surfaces from external surfaces. It can readily incorporate specially selected high temperature body materials to provide form and rigidity where required. A high temperature expanding heat seal mechanism can be provided on the oven device to ensure the device body fills the oven spacer ducting cross-section when inserted through smaller oven door.

Yet further, the invention can incorporate bespoke high temperature attachment mechanisms to allow the hob device to temporarily attach to the hob lid.

Importantly the present invention does not affect cooker aesthetics when installed and eliminates the need for ancillary cooking devices to be used in lieu of heat storage cooker in hotter months.

It should of course be appreciated that the invention is in no way limited to the details of the foregoing embodiments in that any shape and configuration of device structure, whether layered or not, can be provided. If layered, the various layers can be secured by any appropriate means.

Claims

Claims 1, A cooker heat4nsulation device comprising a composite structure arranged to be located in proximity to a cooking surface of a cooker to receive heat therefrom at one side and to provide heat insulation at another side opposite the said one side, the device further including an engagement formation to allow user to readily move the device into, and out of, an operative position with respect of the said cooking surface.
2. A device as claimed in Claim 1, and comprising a composite structure of glass, ceramic and metal materials.
3. A device as claimed in Claim 1 or 2, wherein the device comprises a layered structure.
4. A device as claimed in any one or more of Claims 1,2, or 3, wherein the device is formed of one or more of a layer ofglass-fibre, silica, or ceramic based textiles; stiffening structures; and a one or more layers oflow thermal conductivity insulation material in one of blanket, granule or board form.
5. A device as claimed in Claim 4, wherein opposite outer layers of the device are formed of the glassfibre, silica or ceramic based textile.
6. A device as claimed in Claim 5, wherein the said outer layers are arranged to encapsulate one or more layers of low thermal conductivity insulation material.
7. A device as claimed in any one or more of Claims 1-6, and arranged to be located in proximity to a hob-plate of the cooker.
8. A device as claimed in Claim 7, wherein the shape of the said device conforms to that of the said hob plate.
9. A device as claimed in any one of Claims 6, 7 or 8, wherein the said engagement formation includes means for attachment of the device to a hob-plate lid of the cooker.
10. A device as claimed in Claim 9 wherein the said means for attachment comprise means for attachment to the handle and/or hinge of the said bob-plate lid.
11. A device as claimed in Claim 9 or 10, wherein the means for attachment comprise releasable press-fit formations.
12. A device as claimed in Claim 9 or 10, wherein the means for attachment comprise flexible ties. 3()
13. A device as claimed in Claim 12, wherein the said flexible ties comprise glass-fibre, silica, or ceramic based textiles with or without coatings.
14. A device as claimed in any one or more of the preceding claims, wherein a handle portion is provided on the said another side of the device.
15. A device as claimed in any one or more of Claims 1-6, and arranged to be located in proximity to an opening of an oven compartment of the cooker.
16. A device as claimed in Claim 15, and arranged to be received in the said opening and to allow closure of the compartment by way of an oven door, while operatively in situ.
17. A device as claimed in Claim 15 or 16 wherein said device is of a shape substantially the same as that ofthe said opening of the oven compartment.
18. A device as claimed in Claim 17, wherein the said device is substantially rectangular.
19. A device as claimed in any one or more of Claims 15-18, and including a flange portion.
20. A device as claimed in Claim 19, wherein the flange portion extends substantially around the whole perimeter of the device.
21. A device as claimed in Claim 19 or 20, wherein the flange includes heat insulating material.
22. A device as claimed in Claim 19, 20 or 21, wherein the outer dimensions of the device as defined by the flange portion correspond to an inner cross section of the oven compartment or oven spacer ducting.
23. A device as claimed in Claim 22, wherein the flange portion is arranged to engage with an inner surface of the oven compartment or oven spacer ducting for location of the said device within the oven compartment opening.
24. A device as claimed in Claim 19, 20, 21, 22 or 23, wherein said flange portion is flexible.
25. A device as claimed in Claim 24, wherein the said flange portion is resiliently deformable.
26. A device as claimed in Claim 25, wherein the said flange portion exhibits a temperature-dependent resilience from ambient temperatures up to at least 320°C.
27. A device as claimed in Claim 24, 25 or 26, wherein at least the flange ofthe device includes a shape memory alloy support structure.
28. A device as claimed in any one or more of Claims 15-27, wherein the said engagement formation includes a handle provided on the said another side of the device.
29. A device as claimed in any one or more of Claims 15-28, wherein the said device of heat insulating material is arranged to exhibit resilience.
30. A device as claimed in any one or more of the preceding claims and comprising a factoiy-fitable or user-retro fitable device.
3 1. A heat insulation system for a multi-function cooker and comprising a plurality of devices as claimed in any one or more of the preceding claims.
32. A cooker heat-insulation device substantially as here before described with reference to, and as illustrated in, Figs I -5; 6 -10; 11 and 12; and 13 and l4of the accompanying drawings.Amendment to the claims have been filed as follows Claims 1. A cooker heat4nsulation device arranged to removably fit inside an internal cooker space to reduce direct and indirect heat transfer to, and decrease thermal bridging within, surface structures, the device comprising a layered structure arranged to be located in direct contact with internal cooking surfaces of a cooker to receive heat therefrom at one side and to reduce heat transfer to the inside of the surface at another side opposite the said one side, the device further including an engagement formation r to allow user to readily move the device into, and out of, an operative position with r respect of the said cooking surface. r rIj) 2. A device as claimed in Claim!, and comprising a composite structure of glass, ceramic and/or metal materials.3. A device as claimed in Claim I or 2, wherein the device is formed of one or more of a layer of gIassfibre, silica, or ceramic based textiles; stiffening structures; and a one or more layers of low thermal conductivity insulation material in one of blanket, granule or board form.4. A device as claimed in Claim 3, wherein opposite outer layers of the device are formed of g1assfibr; silica or ceramic based textile.5. A device as claimed in Claim 4, wherein the said outer layers are arranged to encapsulate one or more layers of low thermal conductivity insulation material.6. A device as claimed in any one or more of Claims 15, and arranged to be located in direct contact with a hobplate of the cooker, between a hobplate surface and an inside surface of a hob lid structure.7, A device as claimed in Claim 6, wherein the shape of the said device conforms to that of the said hob plate, and the inside surface of the mating hob lid structure. r r8. A device as claimed in any one of Claims 5, 6 or 7, wherein the said engagement r r formation includes means for attachment of the device to a hobpiate lid of the LI) cooker.9. A device as claimed in Claim 8 wherein the said means thr attachment comprise means for attachment to the handle and/or hinge of the said hobplate lid.10. A device as claimed in Claim 8 or 9, wherein the means for attachment comprise releasable pressfit formations.11. A device as claimed in Claim 8 or 9, wherein the means for attachment comprise flexible ties.12. A device as claimed in Claim 11, wherein the said flexible ties comprise glass..tThre, silica, or ceramic based textiles with or without coatings.13. A device as claimed in any one or more of the preceding claims, wherein a handle portion is provided on the said another side of the device.14. A device as claimed in any one or more of Claims 15, and arranged to be located directly inside the opening of an oven compartment of the cooker, and in proximity to the inside surface of the door structure. r r15. A device as claimed in Claim 14, and arranged to he received in the said opening and r r to allow closure of the compartment by way of an oven door, while operatively in situ, 16. A device as claimed in Claim 13 or 14 wherein said device is of a shape substantially the same as that of the said opening of the oven compartment.17, A device as claimed in Claim 16, wherein the said device is substantially rectangular.18. A device as claimed in any one or more of Claims i417, and including a flange portion.19. A device as claimed in Claim 18, wherein the flange portion extends substantially around the whole perimeter of the device.20. A device as claimed in Claim 18 or 29, wherein the flange includes heat insulating material.21. A device as claimed in Claim 18, 19 or 20, wherein the outer dimensions of the device as defined by the flange portion correspond to an inner cross section of the oven compartment or oven spacer ducting.r 22. A device as claimed in Claim 21, wherein the flange portion is arranged to engage r with an inner surface of the oven compartment or oven spacer ducting for location of r r the said device within the oven compartment opening.LU r23. A device as claimed in Claim 18, 19,20,21 or 22, wherein said flange portion is flexible.24. A device as claimed in Claim 23, wherein the said flange portion is resiliently deformable.25. A device as claimed in Claim 24, wherein the said flange portion exhibits a temperaturedependent resilience from ambient temperatures up to at least 320°C.26. A device as claimed in Claim 23, 24 or 25, wherein at least the flange of the device includes a shape memory alloy support structure.27. A device as claimed in any one or more of Claims I426, wherein the said engagement formation includes a handle provided on the said another side of the device; 28. A device as claimed in any one or more of Claims i427, wherein the said device of heat insulating material is arranged to exhibit resilience; r 29; A device as claimed in any one or more of the preceding claims and comprising a r user-retrofitable device; r r 30; A heat insulation system for a multi4'unction cooker and comprising a plurality of devices as claimed in any one or more of the preceding claims; 31; A cooker heat4nsulation device substantially as here before described with reference to, and as illustrated in, Figsl 5; 6 -10; 11 and 12; and 13 and l4of the accompanying drawings;