ITMI20000792A1 - ELECTRIC STOVE WITH LIMITED POWER HEATING CIRCUITS - Google Patents

Abstract

An electric stove, herein termed "Herna stove", comprising a metal footing (1), vertical walls (6) which are rigidly coupled to the footing and to each other, a top surface (10) for closing the stove which is fixed to the side walls, a heating cavity (5) which is delimited between the footing (1), the side walls and the top (10) of the stove, intake means (11) for aspirating air from the surrounding space into the stove, said means being arranged with an upward and downward orientation, a complex ventilation system (4) for aspirating/delivering ambient air through the air intake and discharge means, the ventilation system being arranged inside the heating chamber, possibly on the internal surface of the top structure with downward and upward flow directions, electric air heating means (7) arranged on the side walls toward the inside of the stove, means (3) for the forced evacuation of the air from the inside of the stove toward the surrounding space which are arranged in the footing. <IMAGE>

Description

DESCRIPTION

The present invention relates to a stove fed with electric energy by means of heating circuits with limited power, for the ecological heating of civil environments.

The stove of the present invention, called "Herna stove", is an innovation with respect to the classic ancient "wood stove" which in the Alps is called "Pigna", that is the typical stove of mountain areas or in any case of European areas with a cold climate. {as in Italy the circle of the Alps, or other areas in Europe such as the Slavic, German and Swiss regions).

The origin of the "stove" is Latin from the Roman period. In fact, the Romans already adopted vertical tubular heating systems in terracotta.

Normally the classic "stove" essentially consists of a vertical masonry structure with the external walls usually covered in tiles, tiles or, to improve the aesthetic and functional effect, also in majolica given the higher thermal conductivity and the higher capacity of the majolica to conserve stored heat. The masonry base of the classic "stove" is integral with the floor of the room where it is installed and, sometimes, two of the four vertical surfaces are integral with the walls of the room.

The stove is hollow inside, creating the so-called hearth, in order to be able to accommodate the firewood and therefore the fire whose "tongues" run through channels formed along the cavities of the internal walls of the stove, transmitting heat to the external surface and then to the surrounding environment.

The interior of the classic stove, that is the cavity that acts as a hearth, is connected to a so-called smoke duct for the evacuation of fumes towards the chimney and also connected to an opening located on the base to allow the combustion air to enter. and allow the "draft".

The classic stove is not without its drawbacks. The classic stove requires the use of wood which, in modern times, is less and less available even in mountain or wooded areas and this for reasons due to the modern lifestyle of people.

The classic stove disperses a large part of the heat through the chimney, so its efficiency is significantly lowered, it uses a fuel (wood) with a rather low calorific value (about 3000 kcal / kg at most) and has an average consumption of 100- 140 kg of wood in 24 hours a day, with an average cost of about Lit.34.000 to maintain 18 ° C in a room 5mx5mx3m high (75 m <3>) when the outside temperature is between -5 ° C and 5 ° C.

The classic stove must be looked after as the fire must be constantly governed and the ashes must be removed, which can lead to a problem and a cost for disposal if the "stove" is operating in city areas.

The present invention aims to provide an artifact which, while repeating the image of the classic stove, overcomes its drawbacks, which does not require wood or other fuel, but which has a high efficiency, surface, radiant walls at 149 ° C with spacers protection, a homogeneous distribution of heat, no heat loss to the chimney, no maintenance and no fire to govern or residues to dispose of.

These objectives and others that will be evident from reading the following description are achieved by an electric stove, here called "STUFA BERNA", which comprises a metal base, vertical walls integral with the base and between them, a top surface for closing the stove which is fixed to the side walls, a thermal chamber delimited between the base, the side walls and the top of the stove, means for the aspiration of air from the environment, inside the stove, arranged in a low-high direction and high-low, a complex ventilation system for suction / delivery of ambient air through the means for the inlet and outlet of the air, the ventilation system being arranged inside the thermal chamber, possibly on the internal surface of said top structure with direction of the flows up-down and vice versa, means for electric heating of the air disposed on the lateral walls towards the inside of said stove, means for for the forced evacuation of the air from inside the stove towards the environment, said means being arranged in said base.

In an embodiment, said stove of the present invention, the air evacuation means are arranged on the side walls, on the bottom and on the top, with single-autonomous and differentiated supply both in terms of pressure and flow rate.

The stove of the present invention will be described in greater detail with reference to Figure 1.

The metal base (1) can be made, for example, from stainless steel sheet or iron painted with thermosetting powder processes baked in an oven at temperatures of 180 ° C and up to 240 ° C.

Approximate dimensions of the base can range from 40 cm x 40 cm x 10 cm thick up to 200 cm x 200 cm x 30 cm thick and over.

Larger dimensions are also possible, since the electric stove of the invention can be assembled at the user for which it is intended and therefore does not impose encumbrance and weight restrictions for transport and passage through doors or stairs.

Other base geometries are possible for example circular, oval or polygonal.

The base can be equipped with pivoting wheels (2), for example 4, 6 or 8 wheels, to allow the stove not to be constrained to a fixed position, as is the case with the classic stove. The wheels can be equipped with a blocking unit on bearings and swiveling.

The major surface, ie the flat surface parallel to the floor, of the base comprises means (3) for the forced evacuation of the hot air towards the room to be heated (top-bottom circuit). These means can consist of a number of holes of variable diameter, quantity and location according to the size and heat capacity of the stove.

The flow of hot air through the stove is promoted by an adequate ventilation group (4) placed inside the stove, in the "thermal cavity" (5) delimited inside the stove that replaces the hearth of the classic stove.

The lateral and vertical walls, which preferably are at least four, are composed of load-bearing structures (6) for example in iron sheet painted with powders baked in an oven at 180 ° C, which have a geometry similar, for example, to that of a tray rectangular with depth, or the third dimension that determines the volume, such as to accommodate the heating means (7) and the external cladding (8).

The external surface (12) of the walls, or the "visible" surface, which constitutes a radiant heating surface, can be formed by majolica tiles both to give a decorative appearance and to improve thermal efficiency.

The heating means (7) of the stove of the present invention are preferably constituted by a mass constituting a thermosetting structure comprising a material previously generically referred to as "feldspar" and a thermosetting chemical binder, with exothermic reaction, this mass by winding an electric cable ( 9) heating.

This material is particularly preferred if it is represented by quartzite silicate (Si02) or by trigonal silicic anhydride (certainly absent from mica) as it is a characteristic of this derivative from metamorphic rock that of homogeneously diffusing heat when made compact, homogeneous, without formation of cracks and / or air pockets to wrap a heating cable powered by electricity. The microcrystals that compose it, if solicited by a thermal source included therein, can be compared to an electrical network made up of infinite microswitches that close distributing the current homogeneously throughout the system. Completeness is obtained with vibrations in the execution phase and by preheating the thermo-heating cable.

The chemical binder used is a thermosetting chemical binder which can be constituted for example by an exothermic reaction mixture aggregated with epoxy resin and amine resin, in order to obtain a thermosetting mixture.

A preferred material comprises 88.5% sand and 11.5% epoxy resin.

The epoxy resin can be chosen from the group consisting of epoxy resins derived from the reaction of bisphenol-A and epichlorohydrin with epoxy equivalent weight 185-196; viscosity at 25 ° C of 12000-16000 cP; relative density 25/25 of 1.16; open vessel flammability 249 ° C, maximum color Garder 3.

The material may also comprise a curing agent such as an amidoamine.

An example of such material that can be used to carry out the present invention is a siliceous product comprising 82.8-83.8% by weight of a mineral aggregate, 12-13% by weight of epoxy resin, 3.7-4.7% in weight of curing agents and 0.03-0.09% by weight of a pigment, called mineral aggregate containing washed sand and quartzarenite.

The same mass consisting of a thermosetting structure can be used for the application and anchoring of the majolica tiles to the surface of the stove when applied to the thermosetting feldspar mass before its exothermic reaction during processing, i.e. before its final hardening. and perennial, the majolica tiles being also partially penetrated by this mass.

The heating cable (9) can be a self-regulating heating element with limited power, with resistance in parallel, which emits temperatures up to 149 ° C which can withstand maximum temperatures up to 260 ° C, being already operational with a minimum temperature of minus 40 ° C.

The preferred type is the self-limiting one with cable matrix for process temperature up to 150 ° C and with preferential power of 66 W / meter, equipped with a nickel-plated copper braid without fluoropolymer protection (and this for a better "grounding" ).

The characteristics of the matrix of the pre-selected thermo-heating cable, of the explosion-proof type, must be such as to allow a "minimum inrush current".

The self-limiting thermo-heating cable is cut to such a length to have the amount of Watts assumed for the power of the heating system envisaged.

The self-limiting thermo-heating cable is "headed" at one end, perfectly insulating the electrically conductive part with respect to the "sock" which acts as an "earth conductor" and with respect to the thermosetting structure of the heating means in order to avoid "short circuits".

The thermo-heating element can be powered from the 220/240 V electrical network, approximately 50/60 Hz; it can operate continuously without interruption and from a power of 66 W / m (at 10 ° C) with an electric current of "initial start" of about 0.3 A / m which is also reduced by 40% when the "regime" is reached, thanks to the structural composition of the chosen feldspar.

A fundamental characteristic of this thermo-heating element consists in the fact that the electrical consumption decreases with the increase of the temperature of the heating cable and of the particular siliceous feldspar-quartzite environment that contains it, and therefore it is possible to obtain large surfaces heated to temperatures around 12Q- 140 ° C with consumption ranging from a few tens of watts up to a few hundred watts without having to distribute the pre-selected thermo-heating cable, of the self-limiting and explosion-proof type, with particular "pitch intensity".

Table 1 shows, for illustrative purposes only and not for the purposes of the invention, examples of parameters relating to thermal panels, i.e. walls of the Herna stove, typically made with majolica, hardened and homogeneous silica mass, limited power heating element, tray of metal containment whose surface is opposite to that on which the majolica is applied, surface facing the inside of the cavity of the Herna stove that defines the radiant surface.

TABLE 1

The thermo-heating element can be made up of one or more distinct circuits so as to be able to allow an electric power supply of the individual circuits through a single switch as well as through a programmed "sequencer" system in order to eliminate an excessive electrical "start" and also for make the "Herna stove" accessible even in the home with a meter with a power limited to 3 kw. a box (13) for the electrical controls is arranged outside the stove. The vertical walls of the stove of the present invention can be made integral with the base and with each other with suitable and functional mechanical fastenings, performed in compliance with all the regulations in force.

The top (10) of the stove of the present invention is closed by means of a structure identical to that of the walls, or even just similar to that of the walls when equipped with only the majolica tile, without a heating system.

An adequate ventilation system that draws air from the environment through the means (11) for the entry of air is arranged inside the stove, in the thermal cavity or on the internal surface of the structure that closes the top of the stove, with withdrawal of high-low flows and vice versa.

The means for the air inlet can be constituted by peripheral upper-lateral passages and / or peripheral lower lateral passages and / or both, regulated by shutters and push the air inside the thermal chamber of the stove of the invention, towards the base and the means for forced evacuation of the air, making it flow through said means provided in the base, in the walls and in the top.

This solution allows the removal of the cold and humid air that tends to remain on the floor of the room and allows a correct and homogeneous distribution of temperature / humidity, without removing dust and in a short time reduces the difference between the temperature of the sucked air compared to the colder and heavier air that would tend to settle on the floor.

The finishes of the external surface, such as edges, etc., can be adapted to the best in harmony with the environment that houses the Herna stove of the invention and / or with the most diverse architectural requirements.

The advantages of the stove of the present invention with respect to the traditional wood-burning stove are also shown in table 2.

TABLE 2

The stove of the present invention has a high efficiency and a low energy consumption.

For each meter of thermo-heating conductor applied to the stove, the inrush current is approximately 0.3 amperes. When fully operational, the consumption of the cable alone is reduced by 27% and up to 40% in relation to the dislocation and the controlled intervention of the air flows.

In the presence of the heating element, as used in the present invention, by keeping the radiant surface at a real temperature around 140 ° C, the operating current and therefore the consumption is reduced by 40-42% with respect to the initial starting point and therefore to the initial start-up absorption (power supply voltage approximately 220 watts single-phase with earth, 50/60 Hz).

An indicative curve of the minimum dissipation for each meter of thermoregulating conductor applied is shown in figure 2.

These results are not achieved even by using

the classic "adhesive mortars", specific cementitious for adhesion of ceramics, tiles, mosaics, etc. (Example of the Keracoloro MAPEI product and the like).

The stove of the present invention has been designed with attention to ecological problems and energy saving, with respect to traditional solutions.

Although it is true that electricity is largely produced by thermoelectric plants, at least in Italy, it is equally true that these thermoelectric plants today are very well managed and every parameter (such as CO, CO2, SO2, NO, NO2 , O2, dust, particulate matter, etc.) is monitored continuously and therefore greater ecological and energy respect is achieved by reducing the myriad of small thermal units using fossil, vegetable, wood, as well as gaseous fuels. Small and medium-sized households are in fact not constantly monitored and therefore are certainly sources of pollution and consequent energy waste.

Furthermore, by contributing to the reduction of the combustion of wood, the stove of the present invention also contributes to the maintenance of the life of the trees, which are essential for the healthiness, but also the containment of the soil and the more natural discipline of the course of water.

In addition, the production of the Herna stove of the present invention does not cause any kind of pollution for its processes, not even of an acoustic type, other than the normal one of a well-run silent workshop.

Claims (8)

CLAIMS 1. Electric stove comprising (1) a metal base; (2) side walls integral with the base and with each other; (3) a closing top structure of the stove, fixed to the side walls; (4) a thermal cavity delimited between said base, said side walls and said top structure; (5) means for the entry of air with pressure and flow rate adjustable from the environment into the thermal cavity, arranged vertically in the structure of the walls and in the top structure; (6) a ventilation system for aspirating air from the environment, through said air inlet means, said ventilation system being arranged in the thermal cavity; (7) self-thermoregulating electric air heating means arranged on said side walls; (8) means for forced evacuation of the air with adjustable pressure and flow rate from said thermal cavity towards the environment, said means being provided in said base. 2. Stove according to claim 1, characterized in that said means for evacuating the air are also arranged on the side walls. 3. Stove according to claim 1 or claim 2, characterized in that said means for evacuating the air consist of holes. 4. Stove according to one of the preceding claims, characterized in that said air heating means comprise a self-thermoregulating heating element. 5. Stove according to claim 5, characterized in that said self-regulating heat-heating element is wrapped in a mass containing feldspar and a chemical binder. 6. Stove according to claim 5, characterized in that the feldspar is constituted by trigonal silicic anhydride. 7. An oven according to claim 6, wherein the chemical binder consists of a mixture of epoxy resin and amine resin. 8. Stove according to one of the preceding claims, characterized in that the side walls are covered with majolica tiles.