HEATING AND/OR COOKING APPARATUS FOR FOODS, HAVING LEVEL CONTROL WITHOUT MOVING PARTS.

Technical Field

The invention relates to an apparatus for heating and/or cooking food portions in water, which is able to heat or cook food placed in it, by means of baskets to au¬ tomatically immerse, drain and discharge the said food, be it pre-cooked, fresh or dried, suitable for use in places frequented by the public; furthermore, the level of the water used in the apparatus is controlled without the use of moving mechanical parts.

Background Art

The state of the art comprises automatic cooking machi¬ nes for food portions, made up of an external housing and an enclosed cooking chamber, to maintain hygene and as protection from steam, in which food is placed in the coo¬ king containers with mechanisms made up of manual loading trays which are made to slide inside the machine; the food is then cooked in the underlying vessel, heated by means of an immersed electric heating element; furthermore, the controlling mechanisms for the containers, to effect im¬ mersion, drainage and discharge, are made up of coaxial shafts that are relatively complex and expensive.

Moreover, with state of the art loading mechanisms it is difficult to completely clean the mechanism, even the most willing operators are often unable to completely clean the said manual loading tray mechanisms; consequently, due to the high temperature and humidity present, food particles introduced that do not go into the underlying vessel, decompose, facilitating the prolifera-

tion of germs and rendering the loading mechanism unhyge- nic.

Furthermore, the use of an immersed electric heating element to heat the water presents a number of difficul- ties in cleaning the element, as it requires a great deal of time to disassemble the parts and to remove the accumu¬ lated scale and food deposits, which, during use, can also be projected onto other parts outside the vessel and the cleaning of which cannot be completely carried out. Furthermore, the state of the art comprises the use of floats of various types which move vertically following the change in level of the cooking water and which thereby activate electrically or mechanically controlled water supply systems. These systems monitor the level continuosly, a feature which is not always desirable as during operation the le¬ vel often varies, in particular during immersion of the food or as a result of knocks and as a result of the dif¬ ferent temperature of the water and of the food placed in it,resulting in unwanted extra water or intermittent supply caused by waves on the surface of the water.

Furthermore, it is possible for the float to become filled with water or to become covered in scale resulting, in both cases, in error or failure to read the correct level.

Disclosure of Invention

Such state of the art may be subject to remarkable im- provements as regards the possibility of eliminating the said inconveniences and by devising a much simpler, econo¬ mic and more hygenic heating and/or cooking apparatus; and/or by ensuring that the reading of the level of the water is indipendent of movements of the body of water.

From what has been said so far, the necessity arises of solving the technical problem of setting up an apparatus for heating and/or cooking food for use in places frequen¬ ted by the public which is practical and easy to use as well as easy to clean; furthermore, the apparatus needs to be of reduced dimensions in relation to its cooking capa¬ city; and/or to have its parts arranged in such a way as to enable the water level to be determined and to be with¬ out moving parts.

The present invention solves the said technical problem by adopting: an apparatus for heating and/or cooking food which includes a heated water vessel and at least a basket for the immersion of the food in the vessel, that does not have a loading mechanism, which has a large access cover on the front and/or top side of the cooking chamber and which has one or more electric heating plates placed be¬ neath the water vessel.

Also adopting: said plate/s fit onto part/s of the ap- paratus that are closed or partially closed; an air space placed near that part/s is connected to it or to the bot¬ tom of that part/s.

Also adopting: two food baskets which rotate on two drive shafts mounted on the same axis and coupled to each other by means of a rotational articulated joint; each drive shaft has a drive coupling to connect them to their respective motors.

Also adopting: a wide plate with heating elements in the sauce warming compartment to heat the sauce containers and/or receptacles and to equalise the temperature.

Also adopting: a water supply tank to supply and/or replenish water in the vessel, placed inside the housing of the apparatus, which feeds the vessel by means of a so¬ lenoid valve. Adopting in a further embodiment, in combination or not

with the one described: an apparatus for heating and/or cooking food portions, having level control without moving parts consisting of a sensor made up of at least two ther¬ mocouples placed at different levels in the sheath, the first close to the lower extremity of the sensor and the second in an intermediate position, so that, when the sen¬ sor is fixed to the bracket, the second thermocouple is positioned just below the desired level of the water in the vessel. Adopting, in addition to one or more of all the pre¬ vious features: the said sensor with thermocouples that measures the temperature difference between the water and the air, in which the thermocouple in the higher position is placed in a horizontal section of the sensor to facili- tate its positioning.

The advantages accomplished by the present invention are: the vessel is heated with one or more external ele¬ ments greatly facilitating its/their cleaning as there are no par-ts that accumulte scale, furthermore, the absence of connector blocks and electrical cables in direct contact with the steam and food in the cooking chamber eliminates the danger of short circuits during cleaning operations or due to the steam in the cooking chamber; the hinged access cover and the placement of food directly into the baskets enables the introduction of items which are not necessa¬ rily of a discrete form but pre-formed, as is often the case with compact blocks of frozen foods which maintain the shape in which they were packaged by the producer;fur- thermore, an apparatus of the same dimensions is able to cook greater quantities of food as the vessel does not contain the coil of the immersed heating element.

A further important advantage is given by the air space behind the cooking chamber, which absorbs the heat radia- ted towards the rear toy the heating plates and expels it

by means of the air flow set up by convection, thereby avoiding localised overheating; furthermore, in the sauce warming compartment the heat obtained from the cooking chamber by means of a fan is combined with the heat gene- rated by the wide heating plate under the receptacles; the equalising action means that the air released into the room with the public no longer contains saturated vapour but is slightly overheated and therefore much less unplea¬ sant for the public. The use of the two thermocouples placed at two diffe¬ rent levels enables the level of the water to be monitored continuously, occasionally or intermittently: for example, it enables it to be monitored at the end of each cooking cycle, thereby disregarding any variations during the coo- king cycle; the tubular sheath containing the thermocouple casings, having a much smaller surface area in contact with the water than is the case with floats, is much less susceptible to encrustations and is less delicate for cleaning operations; finally, the two thermocouples being static take up less space and are less delicate than the mechanical systems with floats, in other words, the system is easier to clean.

A few embodiments of the invention are shown in the drawing tables attatched, in which: Figure 1 shows a par¬ tially sectioned front view of the cooking apparatus as described; Figure 2 is the longitudinal section II-II of Figure 1; Figure 1' is the same view as Figure 1 but with a different mounting system for the heating plate; Figure 2' is the longitudinal section II '-II' of Figure 1'; Figu¬ re 3 is the front view of the actuation mechanism of the baskets; Figure 4 is the partial transverse section IV-IV; Figure 5 is the schematic section V-V of figure 1; Figure 6 is a truncated section of the thermocouples immersed in the cooking water vessel.

The indications are as folows: 1 (Figure 1) is the coo¬ king chamber of the heating and/or cooking apparatus as described in which the transverse horizontal axis 2 is the axis of rotation of the baskets 3 which can be immersed in the vessel 4 of heated water; the rotation is controlled by the motors 5 mounted on the external side of the side panels 6 of the chamber 1 and actuate their respective drive shafts 7 to which the single baskets are attatched; 8 is the slide that guides the cooked food into the chute 9 and on into the tray 10 below; 11 is the solenoid valve that controls the water supply to the vessel by gravity feed from the tank 12; the vessel is placed on the elec¬ tric heating plate 13 housed in the support 14, which in turn is positioned up against the rear panel 15 of the co¬ oking chamber 1: the vessel is also positioned up against the rear panel; 16 (Figure 2) is the air space between the panel 15 and the housing 17 of the apparatus; the air spa¬ ce is connected to the lower part 19 of the housing, which has inlet vents 20, and the outside of the apparatus with vents 18 at the base of the cavity and in the upper part of the panel 17; 21 is the sauce warming compartment in which are placed the sauce containers 22 for ready-made sauces and/or sauce receptacles 23 for specially prepared sauces; 24 is the wide electric heating plate; 25 is the electronic card of the command function and 26 the command panel; 27 is the transparent front/top closing cover of chamber l _r hinged on a transverse axis of the apparatus and having handles 28 for manual opening; 29 are the mobi- le panels, made of transparent plastic material, of the tray compartment _? 14' (Figure 1') is the folded sheet me¬ tal support of the electric heating plate 13; 20' is the lower protective panel for the said plate; 30 (Figure 3) are the adjustable cams for determining the initial posi- tion of the baskets 3 by means of microswitches 31; 32 is

the shaft coupling for the left basket, with a slight ro¬ tational clearance; 33 is the corresponding shaft coupling for the right basket, spring loaded axially to enable ex¬ traction; 34 is the central articulated joint that enables separate rotation of the drive shafts 7; 35 is the extrac¬ tor fan for the cooking vapours with outlet into the sauce warming compartment.

In the embodiment of the invention with level control, the indications are as follows: 36 (Figure 5) is the sup¬ porting structure of the apparatus; 37 is the bench or ba¬ se on which the apparatus stands; 38 is the cooking water; 39 is the sheath of the device for measuring the water temperature with the lower thermocouple 40 and for measu- ring the temperature close to the water level with the up¬ per thermocouple 41; 42 is the normal level of the cooking water; 43 (Figure 6) is the minimum level; 44 is the fixing braket for the thermocouples above the cooking vessel; 45 are the wires that connect the thermocouples 40 and 41 to the electronic control circuit of the apparatus.

The equipment works in the following way: the food, ei¬ ther loose or in portions, is introduced manually by ope¬ ning the cover 27 and placing it in the basket 3 which is in the rest position shown in figure 2; the operator then programs the desired cooking and/or heating cycle on the command panel 26: the basket, controlled by the command program memorized in the card 25, is activated by the mo¬ tors 5, immersed, kept in immersion, drained and then ro- tated to the outermost position to effect the discharge into the chute 9 and the tray 10 below. The slight rota¬ tional clearance of the couplings 32 and 33 enables the food to be jolted to detach it from the basket; the two baskets 3 are activated separately by the two motors and, because of the rotational articulated joint 34, rotate on

the same axis 2 whilst being easily disassembled because of the spring loaded coupling 33.

The electric heating plate 13 will not become covered in scale or food deposits as it is not in contact with the water; any water spillage from the cooking vessel 4 will not affect the plate as it collects near the base 14 where it can easily be removed.

The air space 16 absorbs the heat radiated laterally at the base 14 by the plate 13 and the air flow generated by convection through the lower and upper holes 18 expels the hot air f om the apparatus; an analogous air flow is gene¬ rated under the plate 13, Figure 2', with inlet through the sides of the protective panel 20', which is not herme¬ tically sealed, and escaping through apertures 18 descri- bed.

The wide heating plate 24 warms the sauces in the re¬ ceptacles 23 and/or containers 22 and equalizes the tempe¬ rature in the warming compartment 21; the warming compart¬ ment is also heated by the hot air aspirated by the fan 35 through a transverse opening in the panel 6 (not shown) in the upper part of the chamber 1: the air then escapes from the warming compartment through the openings between the containers 22 and the side walls of the said compartment or through top side vents (not shown).

The level control works in the following way: the lower thermocouple 40 continuously measures the temperature in the water 38 which, apart from natural variations, is the average cooking temperature, whilst the thermocouple 41 measures the temperature close to the surface of the water.

The two thermocouples will measure only a small diffe¬ rence in temperature: the above mentioned variation is sensitive to the surface beacause of the heat radiated up- wards; during operation, and with use, the level 42 will

tend to drop down to the minimum level 43 and, subse¬ quently, the upper thermocouple 41 will be left out of the water and it will therefore measure the temperature of the air instead of that of the water 38; the difference in the temperatures measured by the two thermocouples will be much greater as the air temperature will be much lower than the water temperature: the electronic control circuit will alert the operator of the low level or even effect an automatic replenishment, utilising the solenoid valve 11; the said replenishment will terminate when the two thermo¬ couples detect temperatures that are close enough or equal, ie within a much narrower range, even if the values measured are lower than during the preceding operating conditions, due to the replenishment which is usually carried out with cold water.

The measurement of the level is discontinuous, ie the measurements are only taken at particular moments in the operating cycle: when the food is inserted the level gene¬ rally rises, sometimes quite significantly, causing read- ing errors; with the two thermocouples, however, having established a point in the cycle to carry out the compari¬ son of the temperatures described, measurement of the in¬ stances of variation in the level due to the cooking pro¬ cess are avoided. The measurement of the level can be ef- fected continuously: the effect in the changes in the tem¬ perature, mesured by the upper thermocouple 41, may be re¬ tarded by setting the most suitable moment in the cycle to effect the replenishment, and furthermore, it is possible to change the settings with simple changes to the electro- nic system without intervening on any of the mechanical parts.

If in practice the materials, dimensions and operative details should be different to those indicated, but tech- nically equivalent, the patent will still apply. Thus the

cover 27 described can, less advantageously, not be trans¬ parent and the couples 32, 33 of the drive shafts 7 and the articulated joint 34 can be different from those indicated, though functionally identical. The sheath 39 can be non-rectilinear in form in order to ensure the positioning of the upper thermocouple with respect to the mounting bracket 44.

The base of the vessel can be made more rigid with the adoption of additional metallic structures, technique that is commonly adopted for domestic cooking appliances having radiating electric plates.