Abstract:
A food cooking container provided with an electronic temperature monitoring device, the electronic temperature monitoring device being powered by converting thermal energy into electrical energy by the parasitic exploitation of temperature differences generated between the hot container and a heat dissipating metal mass, and activates a device in the form of a piezoelectric buzzer or LEDs, to indicate pre-set safety temperature limits. The electronic temperature monitoring device includes an electronic thermoelectric harvesting sensor for converting thermal energy into electrical energy via its electronic thermoelectric harvesting system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 USC 119 from Italian Patent Application No. MI2011A002356, filed on Dec. 22, 2011, incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a container, used for food cooking, for which container a utilization safety condition is to be achieved. 
     It is well known that a cooking means can be forgotten on the heat source and that such an event could cause excessive heating, with the danger of fire and damage during food cooking, and damage to the vessel itself. 
     BACKGROUND OF THE INVENTION 
     Usually, commercially available utensils used for food cooking present different devices used as temperature indicators. 
     These indicators are incorporated into the container handles and are intended to provide information regarding the cooking temperature attained or a temperature relating to utensil handling safety on termination of cooking. 
     Known temperature indicator means present in cooking vessels present coverings containing thermochromatic pigments or liquid crystals, which vary in colour according to the temperature assumed by the pan. 
     Temperature indicators have also been conceived containing electronic circuits powered by batteries and used to indicate the attained temperature by digital signals, light signals or acoustic signals. 
     Known temperature indicator systems in food cooking containers have the drawback that if thermochromatic pigments are applied, these lose effectiveness over time due to repeated vessel cleaning. 
     Battery powered devices have problems relating to device safety, because of evident battery explosion danger when exposed to the heat of the vessel, with consequent food contamination, in addition to maintenance and disposal costs. 
     Other recently known temperature indicator devices have the drawback of requiring handles of special size and shape containing seats shaped to match the shape of the indicator device. 
     This fact requires the formation of suitable moulds for handle manufacture, hence increasing the final product cost. 
     Moreover, this permanent incorporation of temperature indicator devices, in particular those battery powered, can generate problems of impermeabilization or heat resistance when, for example, the cooking vessel is cleaned in a dishwasher. 
     A further limit of devices pertaining to the prior art is the fact that for each cooking vessel, for example a frying pan, a saucepan or another container, an indicator device has to be permanently mounted in the handle of each individual container, a fact which substantially increases the vessel cost. 
     EP2361538A1 and EP1889561, incorporated herein by reference, describe cooking vessels according to the preamble of the main claim. 
     SUMMARY OF THE INVENTION 
     The object of the invention is therefore to obviate the drawbacks and limits of the prior art by proposing a food cooking container, the handle of which holds an indicator device for the container temperature, the device being directly activated by utilizing the heat of the cooking container, using the temperature difference created between the heat source and a metal dissipation mass. 
     This object is attained by a food cooking container provided with an electronic temperature monitoring device, the electronic temperature monitoring device being powered by converting thermal energy into electrical energy by the parasitic exploitation of temperature differences generated between the hot container and a metal dissipation mass, and activating a device in the form of a piezoelectric buzzer or LEDs, to indicate preset safety temperature limits. 
     With a device of this type, an aperture can be provided in cooking container handles or handgrips, which can be easily formed in a manner totally independent of the handle shape. The sensor of the electronic device is inserted into this aperture and is brought into contact with a hot part of the cooking container at one end and with a metal dissipation mass constituting the cold part at the other end, hence enabling the temperature gradient of the hot pan/cold mass system to be utilized. 
     The heat originating from the vessel is used to feed the so-called electronic thermoelectric harvesting system which converts the thermal energy into electrical energy, used to generate acoustic or light signals. 
     In detail, it will be assumed that a low power system is used for temperature measurement, provided for example with a piezoelectric buzzer, to warn the user if the measured temperature exceeds a limiting threshold (alarm signal). 
     In the most simple solution, the electronic device can be conveniently formed without a microcontroller and possibly without energy storage elements. 
     In a convenient solution, particularly in relation to withstanding dishwasher action, the thermal indicator device can be made removable, and the removed device be used freely in combination with other cooking containers, provided with a similar conveniently disposed seat. 
     A further advantage of the device is that it can be easily fitted into a handle, because having no battery it only requires a waterproofing protection, which is simple to make. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the device of the invention is described in greater detail hereinafter and illustrated in the accompanying drawings, which are provided by way of example only and in which: 
         FIG. 1  shows schematically part of a frying pan with a handle provided with a seat for the insertion of a metal sheath; 
         FIG. 2  shows the handle with a metal sheath inserted into the seat and locked by a screw; 
         FIG. 3  shows the handle with the measurement device inserted into the metal sheath; 
         FIG. 4  shows an embodiment with the measurement device not removable; 
         FIG. 5  shows a further embodiment with the measurement device not removable. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As can be seen from  FIG. 1 , the food cooking container, for example a frying pan  1 , presents a projecting fixing shank  2  forming a seat for the end  3  of a handle  4 . 
     The end  3  is surrounded by a tubular piece  5  which is rigid with the body of the pan  1 . 
     The handle  4  is locked in known manner with the aid of a screw  6  screwed into the threaded seat  7  of the shank  2 . 
     The handle  4  presents an upwardly open seat  8  into which, as indicated by the arrow (f), a cup-shaped sheath  9  of metal construction presenting upperly an aperture  10  and lowerly a prolongation  11  can be inserted. 
     From  FIG. 2  it can be seen that the metal sheath  9  is inserted into the seat  8  of the handle  4  and the prolongation  11  of the sheath  9  is traversed by the fixing screw  6 , this screw also acting as a means for transmitting the heat originating from the body of the pan  1 . In practice, said prolongation  11  forms the hot terminal of the device. 
     From  FIG. 2  it can be seen that above the handle  4  and above the seat  8  a stem  12  of the measurement and indicator device is shown, indicated overall by  13 , this stem  12  presenting a circumferential band  14  provided with sensors able to receive from the sheet metal sheath  9  the heat originating from the container  1 , to hence create a heat flow which feeds the thermoelectric converter. 
     The stem  12  presents a contact zone  15  which interacts with the cold terminal  16 . 
     The cold terminal  16  consists of a small metal mass of adequate weight and dissipative capacity, preferably of heat conducting material such as aluminium, located in a suitable recess  17  distant from the heat source. 
     The thermal gradient generated by the contact surfaces  14  and  15  is used by the thermal energy conversion device to generate a potential difference by thermoelectric means. 
     This potential difference produces energy to power the measurement and indicator electronics (for example a piezoelectric buzzer or LEDs)  22  able to indicate the attainment of a predetermined limiting temperature, for example 300° C. 
     The device for converting thermal energy into electrical energy by an Energy Harvesting (EH) technique (the so-called electronic thermoelectric harvesting system which converts the thermal energy into electrical energy, used to generate acoustic or light signals) is a semiconductor thermoelectric generator in MEMS (Micro Electrical Mechanical System) technology, allowing to transfer the thermal power from a hot element (hot pole or terminal) to a thermal storage element (cold pole or terminal). 
     The hot side of the thermoelectric device is mechanically and thermally connected to the pan in order to generate a thermal flow through the TEG (Thermo Electric Generator) generator and hence to generate electric power. 
     Such electric power is sent to a support electronics for managing the measuring, controlling and signalling indicators. 
     The cold side of the TEG thermoelectric device is connected to the thermal storage element (cold pole) and suitably is a metal mass (e.g. aluminium), in case in the shape of a dissipater, if necessary. 
     The following are two typical examples of suitable harvesting devices: 
     (1) MICROPELT MPG-D751 thermoelectric generator, described by  Thermoelectric Energy Harvesting , Micropelt GmbH, Freiburg Germany, URL: &lt;www.micropelt.com&gt;, retrieved from the Internet Dec. 21, 2012 and MPG-D651 MPG_D751 Thin Film Thermogenerators and Sensing Devices, Micropelt GmbH, Freiburg Germany, URL: &lt;http://www.micropelt.com/down/datasheet_mpg_d651_d751.pdf&gt;, retrieved from the Internet Dec. 21, 2012, manufactured in MEMS technology. The disclosures of which are incorporated herein by reference. MEMS or Micro-Electro-Mechanical Systems is a technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) made using the techniques of microfabrication. See  What is MEMS Technology ?, URL: &lt;https://www.mems-exchange.org/MEMS/what-is.html&gt;, retrieved from the Internet Dec. 21, 2012. The disclosure of which is incorporated herein by reference. 
     (2) TEC (Thermo Electric Cooler) used in a Peltier cell TEG mode PE-031-10-13 model by Global Component Sourcing described by Global Component Sourcing homepage, URL: &lt;http://www.gcshk.net/&gt;, retrieved from the Internet Dec. 21, 2012;  Welcome to RS Components, Heat - Pump, thermoelectric, Peltier,  9.3W, PE-031-10-13, URL: &lt;http://australia.rs-online.com/web/p/thermo-electric-modules-peltier-effect/4901266/&gt;, retrieved from the Internet Dec. 21, 2012; TE-MODULE RS drawing, URL: &lt;http://docs-asia.electrocomponents.com/webdocs/091a/0900766b8091addd.pdf&gt;, retrieved from the Internet Dec. 21, 2012; and Specification, product: Thermoelectric Module, TE module Part Number: PE-031-10-13, SPC, issued May 29, 2008, URL: &lt;http://pdf1.alldatasheet.com/datasheet-pdf/view/254255/ETC2/PE-031-10-13.html&gt;, retrieved from the Internet Dec. 21, 2012. The disclosures of which are incorporated herein by reference. 
     Although not shown, a battery and microchip can be incorporated into the device  13  of  FIG. 2  or  FIG. 3  if desired. If a battery (see for example the embodiment of  FIG. 4 ) is present then the TEG charges the battery and the microchip can manage the charge of the battery and manage the activation of the piezoelectric buzzer or led  22 , based on the temperature of the pan  1 . 
       FIG. 3  shows the frying pan  1  with its handle  4 , the lower end  11  of the metal sheath  9  being shown locked with the aid of the screw  6 . 
     The stem  12  of the device  13  provided with the sensor zone  14  is inserted into the sheath  9 , with the body of the analysis device  13  resting on the upper part of the handle  4 . 
     The metal sheath  9  remains permanently fixed into the seat  8  of the handle  4 , while the indicator device  12 ,  13 ,  14 , in a convenient embodiment, is removable and is hence not influenced by moisture and detergents, for example during the wash stage. 
     The removed indicator and measurement device  12 ,  13 ,  14  can also be used for handles  4  of other containers  1  which are of appearance, shape and volume different from the container  1  shown in  FIGS. 1 ,  2  and  3 . 
       FIGS. 4 and 5  show by way of example two embodiments in which the electronic device  13  is left permanently on the body of the handle  4  on a compartment  18  provided for this purpose. 
     In the device of  FIGS. 4 and 5  a battery  20  and microchip  21  are present. The TEG charges the battery  20  and the microchip  21  can manage the charge of the battery and manage the activation of the piezoelectric buzzer or led  22 , based on the temperature of the pan  1 . 
     In  FIG. 5 , the compartment  18  is closed by a cover  4   I . 
     In these cases ( FIGS. 4 and 5 ), the device compartment  18  must be made impermeable. 
     The hot thermal terminal  11  can also be located in the immediate vicinity of the edge  11   I  of the container  1  or on an appendix  11   II  thereof, depending on the available geometry. 
     The cold terminal  16  is located towards the end of the handle. 
     In all applications, the constituent metal mass  16  of the cold dissipation terminal can have knurls or fins to increase the heat transmission power.