A VESSEL FOR PREPARATION OR COOKING OF E.G. FOOD-STUFFS AND BEVERAGES BY HEATING

Abstract: A method for controlling a heating procedure in an oven by using an optically readable information carrier with or on the heating object. The oven may be provided with an optical reading device for touchless reading of the information carrier before and/or during the reading. By providing the information carrier with one or more fields that exhibit color shift at temperatures at will, a feed-back control of the procedure is made possible with simple technical solutions. The special feature of the method is the use of an additional information field for control of the start of the oven.

Description: A VESSEL FOR PREPARATION OR COOKING OFE.G. FOOD-STUFFS AND BEVERAGES BY HEATING The present invention relates to a vessel, particularly to a vessel having walls of a material which permits heating of the content of the vesssel by radiation, in particular micro-wave radiation. Such vessels, and the term vessel is used here to include also packages and containers of different kinds which normal¬ ly, at least partially, have walls of a material which depends on the actual kind of heating. If the heating takes place by heat radiation of the type infrared heat radiation from e.g. a cooking plate, the material may be metal, at least in the bottom. If the heating takes place by means of the nowadays very common heating type using micro-vawes, then the material may be cardboard or plastics or the like. Below, to facilita¬ te, such vessels, along with the instant content in each case, will sometimes be referred to as "object". Common to all types of heating is the problem of accura¬ tely controlling the temperature, e.g. to prevent that the temperature is insufficient for the application in question or to prevent that the vessel as used bursts up and starts lea¬ king due to too a high internal pressure within the vessel, which may happen if the temperature has unintentionally become too high. To achieve such a temperature control it is known to pro¬ vide the vessel with an information carrier having one or more optically readable control information fields which informa¬ tion carrier is adapted to be used in order to indicate the temperature of the object as the object is heated in an oven. Here, it is conceivable, for instance, to watch visually how the information carrier shifts color as the desired tempe¬ rature has been reached, so that the heating procedure may be stopped then. However, the information carrier is preferably adapted to cooperate with an optical reading device of the oven and a control device to control the heating procedure at least partially in dependence of the read temperature informa¬ tion. It is preferred that the information carrier is arranged directly on the heating object, e.g. as a disposable label or, alternatively, as a device for repeated use, which device is applied on the object, its vessel, package or contaner, e.g. as the heating is performed. The information carrier may comprise a field of tempera¬ ture sensitive color which exhibits a color shift at the desi¬ red end temperature of the object, preferably the ready-tempe- ratureof a food-stuff or a beverage. It is conceivable that the information carrier has the shape of a label or a device for use in an oven having a ligh¬ ting within the oven cavity, in which case the information carrier preferably is characterized in that the field with temperature sensitive color is composed of two layers, viz. an uppermost layer, which shifts from transparent into non-trans¬ parent, or vice versa, at a color shift, and a lowermost lay¬ er, which exhibits fluorescense at activation by the oven cavity lighting. Prior to describing the invention in more details with reference to the figures in the drawing it might be worthwhile to make some general remarks with respect to the invention, viz. that the invention generally is based on the concept that it is possible to utilize optical reading for the provision of a control system for an oven, which is partially associated with the oven itself, and the technical establishment thereof, and which is partially associated with the object or the food¬ stuff which should be subjected to heating/preparation,and, further, the realization that such a system, particularly the case with feed-back control, which in known ovens is solely associated with the technical establishment of the oven, may achieve considerable simplifications in the design of the control system of the oven and the general operation of the oven, and that this may be achieved while utilizing cost effi¬ cient technical solutions that are known per se by those skil¬ led in the art. There exists no principal limit for how much control information may be taken from the information carrier. Just as well as the information carrier may hold information for choice of a pre-set program with the control unit of the oven, the information carrier itself may comprise the control program, which is then read into the control unit at the ac¬ tual use. In the present case the term optical reading is used, e.g. reading while using light vawelengts within the optical range, but also other vawelengths may be possible. Thus, the information carrier may comprise fields with chrys- talline or similar substances which at activation by scanning radiation my be cauesd to emit their information by discree vawelengths or within defined vawelength-rangesa. A feedback control may be achieved in that these substances are adapted to emit radiation of a temperature dependent vawelength. An important requirement by heating as set forth above is that the system operates reliably and only for packages of a predetermined kind. This is achieved according to the inven¬ tion According to a further development of the invention in that the vessel is provided with a further characterizing fea¬ ture in the shape of an additional, temperature non-sensitive color marking which is disposed in such a manner that it can be detected by a further detecting device, adapted to control the start of the heating procedure. Only vessels having a marking that controls the stop of the heating are provided with the additional color marking, which results in that if a vessel that lacks both kinds of markings is inserted into e.g. a microvawe oven having an indicator for stopping of the hea¬ ting then no heating can be started. In this way it is preven¬ ted that a heating is started that cannot be automatically in¬ terrupted at the desired temperature. This additional, temperature non-sensitive color marking is preferably black, whereby interfering reflexions may be largely avoided on detekting by means of light within the infrared vawelength range. The temperature sensitive color can be applied by paint¬ ing or by printing the color directly on at least one of the vails of the vessel. As the temperature sensitive color may contain liquid chrystals and may be difficult to apply by printing procedures it may be advantageous to have to color applied to a base having a self-adhering glue on one side thereof, by means of which the color marking may be affixed to at least one of the walls of the vessel. If the vessel has a plastic covered surface then the marking may be detached after use in order to be used repeatedly. Such color markings, ha¬ ving different temperature definitions, may be stored on a storage sheet and may be moved to and from a vessel as desi¬ red. Tests have verified that the temperature of the content of the vessel is only slightly higher than the temperature of the outer surface of the vessel. Only at temperature higher than about 65 °C and up to 95 °C will the temperature of the surface be about 5 °C lower. It is possible to compensate for this by the manufacture of the colormarkings, e.g. by dispo¬ sing the color markings interiorly of a vessel made wholly or partly of a transparent material, so that the color marking is visible from the outer side. The invention is disclosed in more details below with reference had to the accompanying drawings which schematically show various exaples of vessels according to the invention and wherein figure 1 is a perspective view of a vessel according to a first embodiment, used as an example, figure 2 is a side elevation of a vessel according to a second example, disposed in a micro-vawe oven, figure 3 is a side elevation of a vessel according to a third embodiment disposed on a heating plate, figure 4 is a perspective view of a vessel acording to a fur¬ ther embodiment, and figure 5 is view of a chart of color mar¬ kings and a partial view of a vessel having a marking for disposition of color marks. Figure 1 shows a vessel of conventional type, containing water and a capsule with instant coffee powder (not shown) . The content of the capsule should be heated up to 93 °C in order for the capsule to open, and, thus, in order for the coffee so produced to have the correct serving temperature. Therefore, the container is provided with a temperature sensi¬ tive color marking 2 which shifts color at a temperature of the outer surface of the vessel that corresponds to a tempera¬ ture of 93 °C of the coffee within the vessel with an ordinary performed cooking, which has to be determined from case to case. On an adjacent side the container is provided with anot¬ her temperature-sensitive color marking 3 which shifts its color at a temperature of 80 °C of the content of the contai¬ ner. Further, the container 1 is provided with a color mark 4 which denotes that the container is intended to be used for heating in a micro-vawe oven having automatic means for con¬ trol of the heating up to the desired temperature. Such an oven 5 is shown schematically in figure 2. A container 1 of the kind as shown in figure 1, although made from a transparent material and having a color marking 9 dis¬ posed internally of the container, is placed in the oven in a guide 6 for the lowermost part of the container with the color marking 2 facing a sensing device 7. Simultaneously, the color mark 4 is positioned opposite a second sensing device 8. When the oven is switched on the sensing device 8 senses the existence of the color mark 4 and activates a relay or the like so that the oven starts the heating. Within a few minutes the content of the container has reached the desired 93 °C and the color mark 2 shifts color which is sensed by the sensing device 7 which interrupts the heating through a relay or the like (not shown). In case a heating to only 80 °C had been desired then the container should have been placed in the oven with the color mark 3 facing the sensing device 7. The design of the oven 5 and of the devices 7 and 8 do not form a part of the invention, and therefore they are not described in more details here. Sometimes, particularly with containers that may be open¬ ed and resealed, it is desirable to determine the heating temperature from case to case. It is then possible to use self-adhering color markings that are applied to the container in question. Such color markings on a carrier 21 of self-ad¬ hering plastics are shown in figure 5 and are denoted 22, 23 and 24 for the temperatures 60 °C, 80 °C and 93 °C, respective¬ ly, and are affixed to a chart 25. To facilitate detaching the carriers 21 are provided with a flap, that is non-adhering and on which the temperature values are preferably printed. One such color marking is adapted to be affixed to a container which is provided with a an indication 30 where the color marks 22, 23 och 24 are to be placed in order to get a correct position within the micro-vawe oven. If desired,the color markings may be detached from the container 1 after use, and again affixed to the chart 25 for repeated use a number of times.

Claims: C L A I M S. l.A vessel for preparation of e.g. food-stuff and bever¬ ages by heating, provided with an information carrier having one or more optically readable control information fields which information carrier is adapted to be used in order to indicate the temperature of the object as the object is heated in an oven, said information carrier being adapted to coope¬ rate with an optical reading device of the oven and a control device to control the heating procedure at least partially in dependence of the read temperature information, said informa¬ tion carrier further being arranged directly on the heating object, e.g. as a disposable label or, alternatively, as a device for repeated use, which device is applied on the ob¬ ject, its vessel, package or contaner, e.g. as the heating is performed,said device comprising a field of temperature sensi¬ tive color which exhibits a color shift at the desired end temperature of the object, preferably the ready-temperature of a food-stuff or a beverage, characterized in that the vessel is provided with a further characterizing feature in the shape of an additional, temperature non-sensitive color mar¬ king which is disposed in such a manner that it can be detec¬ ted by a further detecting device, adapted to control the start of the heating procedure. 2. A vessel as claimed in claim 1, characterized in that the information carrier is arranged on the inner surface of a vessel which is manufactured at least partially from a trans¬ parent material, so that the color markings are visible from the outer side. 3. A vessel as claimed in claim 1 or 2, charactrized in that the vessel is provided with a plurality of color markings which shift color at different temperatures. 4. A vessel as claimed in one or more of claims 1 to 3, characterized in that the vessel is provided with at least one additional, temperature non-sensitive color marking, which is disposed in such a manner that it can be detected by a further detecting device, adapted to control the start of the heating procedure. 5. A vessel as claimed in one or more of claims 1 - 4, characterized in that the additional color marking is chosen in such a manner that it to a large extent eliminates or av¬ oids interfering reflexions by sensing by means of light with¬ in the infrared vawelenth range, preferably in that the color marking in question is black. 6. A vessel as claimed in one or more of claims 1 - 5, chraceterized in that the information carrier has the shape of a label or a device for use with an oven having an oven cavi¬ ty lighting, wherein the information carrier field with tempe¬ rature-sensitive color preferably is built up of two layers, viz. an uppermost layer, which shifts from transparent into non-transparent, or vice versa, at a color shift, and a lower¬ most layer, which exhibits fluorescense at activation by the oven cavity lighting. 7. An information carrier in the shape of a label or a device as claimed in claim 6 for use with an oven having an oven cavity lighting, characterized in that the field with temperature sensitie color is built up of two layers, viz. an uppermost layer, which shifts from transparent into non-trans¬ parent, or vice versa, at a color shift, and a lowermost lay¬ er, which exhibits fluorescense at activation by the oven 8. A preparation vessel or container for use in an oven for heatin/preparation of a food-stuff or a beverage which is put into the vessel or container directly or in its package, where the oven comprises a reading device for touchless read¬ ing of an optically readable information characterized in that the vessel or container comprises an information carrier, adapted to be read by the reading device and having one or more optically readable information fields, comprising control information for control of a heating/preparation procedure for the food-stuff or beverage. 9. A vessel or a container as claimed in claim 8 for use with an oven having an oven cavitylighting, characterized in that the field with temperature-sensitive color is built up of two layers, viz. an uppermost layer, which shifts from tran¬ sparent into non-transparent, or vice versa, at a color shift, and a lowermost layer, which exhibits fluorescense at activa¬ tion by the oven cavity lighting.

Inventors: AAKERLIND JAN, AAKERLIND, JAN
Applicants: AAKERLIND JAN, C D CATERING DEV AB, AAKERLIND, JAN, C-D CATERING DEVELOPMENT AB
Application year: 1996
Main classification: G01K11
IPC codes: A47J36, F24C7, G01K11, H05B6