WO2019052620A1

WO2019052620A1 - Electric heating system (its variants)

Info

Publication number: WO2019052620A1
Application number: PCT/EA2018/000006
Authority: WO
Inventors: Vasilii Arsenevich KHABUZOV
Original assignee: Khabuzov Vasilii Arsenevich
Priority date: 2017-09-14
Filing date: 2018-09-10
Publication date: 2019-03-21
Also published as: EA038845B1; DE212018000321U1; EA201700439A1

Abstract

The claimed invention refers to electric heating systems, powered by AC mains with a frequency of 50-1000 Hz that use resistance heating elements as heat-generating elements. In the claimed system the electric shock protection device, executed on the basis of the safe dividing transformer, is additionally equipped with the generator, series-connected between AC mains circuit and the safe dividing transformer, at that the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal. The claimed invention allows to produce modern electrically safe energy-efficient noiseless heating systems of enhanced comfort.

Description

ELECTRIC HEATING SYSTEM (ITS VARIANTS)

The claimed invention refers to electric heating systems, powered by AC mains with a frequency of 50-60 Hz, or 400 Hz, or 1000 Hz, which use resistance heating elements, tor example, film-type two-dimensional elements on the basis of carbon fibers, current-conducting films, heating cables, heating nets and clothes, band, bar or wire heaters, heating elements on the basis of current-conducting liquids, heating elements, specially intended for the heating of transparent or reflecting surfaces, for example, windows, windshields, mirrors_*

The claimed invention allows to produce modem electrically safe energy-efficient noiseless heating systems of enhanced comfort for residential, public, industrial rooms, vehicles, facilities of an agricultural nature, such as greenhouses, animal houses, warehouses, facilities of a street and park and garden nature, such as heated alleys, sidewalks, steps, benches, roadways, for snow melting and anti-icing systems, such as roofs and canopies, for regular and special clothes with heating, for bedding, such as electric; plaids, electric blankets, for Items of a sanitary and hygienic nature, such as water-closet pans and bidets with heating.

At the moment main part of electric heating systems are powered by industrial AC mains with a frequency of 50/60 Hz with the rated operational voltage in the range of 110-420 Volts, and autonomous objects with a local electric system (airplanes, vessels, other means of transport) are powered by AC mains with a frequency from 400 to 1000 Hz with the rated operational voltage of hundreds of Volts. The contact of a user with current-conducting parts of heating systems, powered by such power sources, can result in the electric shock hazard. From the prior art means of user protection from the electric shock in electric devices, including electric heating systems, are known.

In GOST R IEC 335-1 -94 Safety of Household and Similar Electrical Appliances the use of basic insulation, double or reinforced insulation of current-conducting parts, arrangement of a ground loop, in other words, enveloping of current-conducting circuits of devices with a current- conducting grounded shield that prevents a user from a direct contact with current-conducting parts, is envisaged as electric shock protective means.

As per the indicated GOST, an electric circuit is considered safe if its RMS voltage is less than 42.4 Volts that is determined by international standards as a "safe extra low voltage".

A universal and reliable way to ensure the electric safety, regardless of measures taken with the purpose of electric insulation of current-conducting parts with help of electric insulating materials and structures, is the incorporation of a specialized device to electric heating systems, a functional element that reduces the RMS value of heating elements to a safe level, for example, 12, 24, 36 or 42.4 Volts and, most importantly, ensures a galvanic isolation of electric circuits of power supply industrial mains or local power supply mains and heat-producing elements.

This functional element, representing an electric shock, protection device, is a safe dividing transformer that reduces the RMS voltage of load electric circuits to a safe extra low voltage, and also ensures a galvanic isolation between the supply mains circuit and load circuits. In a specialized literature, the "safe dividing transformer" is often called also the "safe isolating transformer" or "safe step down transformer' .

In GOST R IEC 335- 1-94 Safety of Household and Similar Electrical Appliances this transformer is defined as a "safe dividing transformer", in other words, the transformer, the input winding of which is electrically isolated from the output winding with help of the insulation that is equivalent to, at least, double or reinforced insulation, and that is intended for the powering of the device or its circuits with a safe extra low voltage,

The system of a room electric heating, namely, intended for the use in the underfloor heating with a supply voltage of 220 VAC, frequency of 50-60 Hz, in which the Heat Plus infrared film with a thickness of 0.5 mm, produced by the South Korean company Seggi Century Co.Ltd as a heat-generating resistance heating element with 8 layers, applied to a carbonic conductive basis (9th layer), four of which represent a reinforced double electric insulation of current-conducting parts, that is main and only mean of ensuring the electric safety of the heating system, is known from the state of art (see information on the web-site in the Internet at the following URL: www.ec2.1 .corn).

From the state of art the room electric heating system with a ceiling film electric heater with a resistance heat-generating element is known (RF patent for invention No.2389161 , priority date 03.10.2008, published on 10.05.2010, patent holder "Racionalnye otopitelnye sistemy" LLC). In this system insulating films of increased thickness are used as means of the electric safety ensuring; they additionally protect the electric heater from the current breakdown in the event of mains overload and from mechanical damages of the resistance heat-generating element. The indicated system is powered by AC supply mains with the RMS of 220 Volt.

The disadvantage of this room heating system is that the increase of electric insulation layers thickness adversely affects the thermal effectiveness of the heating system in general, due to a low thermal conductivity of electric insulating materials, preventing the heat transfer from the protected resistance component to the surface of the heat-generating element that results in the growth of power consumption for heating.

From the state of art the electric heating system with the use of the HeatLife 220/M2 film with grounding, produced by a Korean company Ondolia Co., Ltd, as a resistance heat-generating element, is known. The multilayer structure of the heat-generating film is given in the Internet at the URL: http://www.heatlife.ru/product-details/hl-220-m2/, its structure is patented in South Korea along with the Korean Institution for Industrial Technologies, application for the invention KR20100087907, published on 06.08.2010.

The indicated heating film with grounding 220/M2 is used for a full single heating of rooms, including wet areas (shower rooms, pools, bathhouses). As an additional electric safety mean of the heating system, additional current-conducting layers of grounding, arranged above and below of isolating layers of the heating resistant element, are used.

An additional current-conducting grounding layer accumulates static electricity and current leakages from the film surface, and a separate copper bus collects them for further discharging to the grounding network.

From the state of art the system of electric heating of rooms or vehicle cabins as per the RU utility model patent No.7729, priority date 20.1 L1997, published on 16.09.1998, is known; it contains a floor heating device made in the form of a current-conducting paper plate on the basis of a discrete carbon fiber, from both sides clad in polyamide fiberglass, laid on a thermal insulating material, covered with a layer of flooring (tile, laminated plastics).

The indicated heating system is connected to AC mains with a voltage of 220V with a frequency of 50-60 Hz directly or through the safe dividing transformer.

This utility model uses two electric safety means in the form of reinforced electric insulation of current-conducting circuits, and the possibility of connecting of the resistance heating element to the electric network through the safe dividing transformer, operating at a supply mains voltage, that ensures the reduction of the supply voltage to a safe level. The disadvantage of this system is an acoustic noise of the operating safe dividing transformer.

From the state of art the room eiectric heating system with the use of a safe low voltage not more than 30 Volts, application for the invention PCT/KR 2003/002750, priority date 16.12.2022, the date of international application 16.12.2003, the date of international publishing WO 2004/056155 from 01.07.2004, chosen as a prototype, is known.

This heating system is powered by AC industrial mains with a voltage of 1 10V/220V, frequency of 50-60 Hz, the system electric safety is ensured by the use of the safe dividing transformer, that ensures the reduction of a supply voltage to a safe level, and also by the galvanic isolation of the supply mains contour and the contour of the resistance heat-generating element.

In the indicated system the safe dividing transformer operates at a supply mains frequency, in other words, at a frequency of 50-60 Hz. This transformer is called a low frequency transformer.

Nevertheless, the use of a low frequency transformer, operating at a frequency of an industrial mains of 50/60 Hz, as a mean of ensuring the electric safety of the electric heating system, has disadvantages that inhibit the growth of use of energy effective heating systems with resistance heating elements, especially of a film two-dimensional type, especially for living rooms.

From the state of art it is known (GOST 12.2.024-87 Occupational safety standards system (OSSS). Noise. Power oil-immersed transformers. Norms and control methods) that low-frequency transformers during operation generate vibrations and acoustic noise on frequencies multiple of the supply mains frequency of 50/60 Herz.

In the prototype acoustic vibrations, generated by the low frequency safe dividing transformer, operating at a frequency starting from 50-60 Hz, are the consequence of appearing mechanical vibrations of windings and magnetostriction of the core by the action of an alternate magnetic field, created by windings of the transformer when alternating-sign current passes through them.

All other conditions being equal (frequency, voltage, temperature), power of acoustic radiation (noise), generated by the transformer during operation, is proportional to the transformer power. The higher is the transformer power, the bigger are its weight and dimensions, and also acoustic radiation (noise), generated by it.

As heating systems are characterized by a quiet high power of energy consumption, they use low-frequency transformers of significant dimensions and weight that generate a constant acoustic noise during operation.

Additional measures on the noise and vibration insulation of low frequency transformers, installed in heated rooms, increase expenditures for the arrangement and operation of the heating system. There is also a similar problem of interior arrangement of rooms, caused by significant dimensions and weight of low frequency safe dividing transformers as in a heated room it is necessary to provide for significant additional spaces, or structural elements, or separate elements of furniture for the arrangement of the big tow frequency safe dividing transformer (see the video "Carbontec floor heating systems" at the web-site in the Internet at the URL: .http://carbontecras..ru/').

The frequency of acoustic radiation of transformers, operating at an industrial mains frequency of 50/60 Hz, lays in a frequency domain, well audible for a man or animal. The constant presence of a man or animal in a heated room, in which a single tone noise of a humming transformer is constantly audible, violates acoustic comfort conditions of staying in such rooms.

If the low frequency safe dividing transformer is installed outside a heated room in order to decrease the audibility level of a generated acoustic noise, it does not solve the noise issue completely, as there is the transfer of vibrations (noise) through elements of structural units of buildings. At that another problem occurs, namely, the problem of decreasing the energy efficiency of the heating system due to the following reasons.

On the first hand, the efficiency value of low frequency safe dividing transformers, used as electric safety devices for heating systems, is not more than 94-96%.

The placement of the transformer outside a heated room means that thermal losses of the transfer will dissipate outside the heated room, therefore, the energy efficiency of the heatmg system will be for at least 4%...6% lower in comparison with the placement of the safe dividing transformer directly in the heated room.

On the second hand, the use of safe extra low voltage values for the supply of resistant heat-generating elements, requires a proportional increase of the intensity of current, flowing in the circuit of heating elements, to maintain the generated thermal power by the heating system. The increase of the current value, flowing in the circuit of heat-generating resistance elements, requires the increase of the cross-section of leads.

Besides, the increase of the length of leads due to the remote placement of a transformer additionally decreases the energy efficiency of the heating system due to additional nonproductive ohmic losses in wires, and increases the labor intensity and materials consumption of the heating system assembling and, respectively, increases the cost of the heating system and the cost of its operation.

The task of the claimed invention is the development of a noiseless, electric safe and energy effective system of electric heating.

The set task is solved in that in the first variant of the electric heatmg system, powered by AC mains of a frequency in the range of 50-1000 Hz, containing at least one resistant heating element and electric shock safety device, series-connected between the AC supply mains circuit and resistant heating element, made on the basis of at least one safe dividing transformer, the electric shock safety device is additionally equipped with a generator, series-connected between the AC supply network circuit and the safe dividing transformer, at that the generator input is connected to AC mains, the generator output is connected to the primary winding of the safe dividing transformer, and the output winding of the safe dividing transformer is connected to the resistance heating element. With regard to the above mentioned, the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal

In the second variant of execution of the system of electric heating, powered by AC mains with a frequency in the range of 50-1000 Hz, containing at least one resistance heating element and the electric shock protection device, series-connected between the electric network supply network and the resistance heating element, executed on the basis of at least one safe dividing transformer, the electric current protection device is additionally equipped with a generator, series-connected between the supply network circuit and the safe dividing transformer and at least one output rectifier, series-connected between the safe dividing transformer and the resistance heating element. Furthermore, the input of the generator is connected to AC mains, the output of the generator is connected to the primary winding of the safe dividing transformer, the output winding of the safe dividing transformer is connected to the input of the output rectifier, and the output of the output rectifier is connected to the resistance heating element, at that the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal. In the third variant of the execution of the system of electric heating, powered by AC mains with a frequency in the range of 50-1000 Hz, containing at least one resistance heating element and the electric shock protection device, series-connected between the supply network circuit and the resistance heating element, executed on the basis of at least one safe dividing transformer, the electric shock protection device is additionally equipped with the generator, series-connected between the supply network circuit and the safe dividing transformer, and series-connected between the safe dividing transformer and resistance heating element at least one output rectifier and at least one unit of polarity reversal of output voltage of the output rectifier. With regard to the above mentioned, the input of the generator is connected to AC mains, the output of the generator is connected to the primary winding of the safe dividing transformer, the output winding of the safe dividing transformer is connected to the input of the output rectifier, the output of which is connected to the input of the unit of polarity reversal of output voltage of the output rectifier, the output of which is connected to the resistance heating element, at that the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearings by ears of a man and/or animal

The electric shock protection device in all execution variants of the invention can be completely or partially executed in the form of a room interior feature, for example, of a picture.

It is well known that the system of electric heating that uses the heating element of a two-dimensional film type with minimum number and thickness of protection layers, ensuring the electric safety and mechanical protection of current-conducting parts of heating elements, is the most thermal and cost efficient in operation from the perspective of minimization of room heating expenditures. Nevertheless, when reducing the number and thickness of protection layers of the heat-generating element in the struggle for thermal and cost efficiency of the heating system, the problem of heating system electric safety, powered by electrically hazardous industrial and commercial AC mains with a frequency of 50-1000 Hz, occurs. .

One of way s to maintain the thermal and cost efficiency of the electric heating system when observing required norms of its electric safety is the use of the safe dividing transformer. The installation of the safe dividing transformer in a heated room is the most rational from the perspective of increase of the thermal efficiency due to the use of heat, generated by the transformer during its operation, for the room heating.

Low frequency transformers, powered by commercial, industrial AC supply mains with a frequency of 50-1000 Hz, are now widely used for ensuring the electric safety of the heating system,

Low frequency transformers inherently combine a simple structure and functions of reduction of the operational voltage to the safe level and galvanic isolation of supply network circuits and heat-generating elements circuits. The advantages of low frequency transformers include the fact that at the transformer output there is alternating current that can be directly supplied to heat-generating elements. The operation of electric circuits of heating elements at alternating current, as distinct from their operation at the direct current, significantly decreases the rate of the galvanic corrosion of current- carrying components of the circuit of heat-generating elements and helps to the increase of the operational reliability of the heating system, especially during operation under conditions of increased humidity.

Nevertheless, low frequency transformers, installed in a heated room for the provision of electric safety of the heating system, operating at a frequency of the industrial network of 50-1000 Hz, are sources of a constant single tone (with harmonies multiple of the supply mains frequency) of the acoustic radiation (noise), violating conditions of comfortable staying of a man and/or animal in a heated room.

The amplitude (loudness) of the acoustic radiation, generated by the transformer, is proportional to its weight and dimensions, in other words, the higher is its power, required for the room heating, the bigger are the weight and dimensions of the transformer, used for the provision of electric safety, the higher is the intensity of the acoustic radiation (noise), generated by it.

The effective solution of the task of maintaining the acoustic comfort in a heated room, in which the transformer is located, at simultaneous maintaining a high electric safety of the heating system and its thermal effectiveness and, as a consequence, its economical operation is the additional provision of the electric safety device with a generator, series-connected between the supply network circuit and the safe dividing transformer, the operational voltage of which is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal.

The generator ensures transformation of the current frequency of commercial, industrial mains of 50-1000 Hz in alternating current, the frequency of which is out of the frequency domain of hearing by ears of a man and/or animal, for example, frequency above 20000 Hz.

Such frequency electric signal comes to the input of the safe dividing transformer that starts to generate an acoustic signal of the same or multiple frequency that will also be out of the hearing by ears of a man and/or animal, ensuring the acoustic comfort of their staying in a heated room, in other words, the safe dividing transformer will not generate a single tone, annoying humming during operation.

The first variant of the invention is effective and reasonable for use in cases when the electric safety device, comprising the safe dividing transformer, is located very close to the resistance heating element, in other words, it has short connecting wires with the resistance element that have low values of own parasitic inductance, and the resistance heating element itself represents a two-dimensional film heating element that also has a low value of own parasitic inductance. A low value of the parasitic inductance of connecting wires and the resistance heating element allows the high frequency current of more than 1000 Hz, for example, with a frequency of 10000 Hz to flow freely in the load circuit.

The second variant of the invention is designed for cases when the safe dividing transformer is placed at a significant distance from the resistance heating element and connecting wires between the output of the safe dividing transformer are longer, and due to that fact they have an increased value of own parasitic inductance; at that, the resistance heating element can be executed as a two-dimensional film heating element with a low parasitic inductance; or, in the second case, when connecting wires between the output of the safe dividing transformer are longer and due to this fact they have a high value of the parasitic inductance, and the resistance heating element is of a cable, band or reel type with a high value of parasitic inductance.

High level of the inductive component of the electric heating system load circuit prevents the current from passing through the heating element. At the same time, due to the reduction of the current value, passing through the heating element, the level of generated thermal power falls down, and the thermal efficiency of the heating system decreases. To compensate an insufficient heating of the resistance heating element in the heating system with a high value of the parasitic inductance and a high value of heating alternating current, it is necessary either increase the voltage value in the load circuit that contradicts with the requirements of the system electric safety, or switch to the supply of the heating element with rectified (direct) current.

To solve this issue, it is necessary to connect in series between the output of the safe dividing transformer and a circuit of the resistance heating element at least one rectifier that transforms alternating current from the output of the safe dividing transformer to rectified (direct) current that is supplied to the load circuit,

At that, the value of the inductive component of connecting wires and the resistance heating element does not matter anymore as it is known that the presence of the inductive component in a cun-ent-conducting circuit does not obstruct the flow of rectified (direct) current.

Therefore, the construction of the second variant of the electric heating system allows to exclude limitations on the special arrangement of the electric shock protection system operating at high frequencies (more than 1000 Hz), and constructions of resistance heating elements. With regard to the above mentioned, the energy efficiency of the heating system is maintained due to the possibility of placing the electric shock protection system on the basis of the safe dividing transformer, and also current conducting circuits, inside a heated room. In addition, the acoustic comfort of the heating system is maintained due to the noiseless operation of the safe di viding transformer.

The third variant of the invention is designed for cases when the electric heating system is arranged in wet areas. When placing resistance heating elements and other current-conducting circuits of the electric heating system in wet room conditions, such as a bathroom, balcony, pool, garden alleys, greenhouses, animal houses, farms, while using rectified (direct) current, in the load circuit, there is a hazard of accelerated corrosive galvanic damage of current conducting circuits and elements, resulting in a breakdown of electric insulation of current conducting circuits in areas of corrosion that leads to an early failure of the electric heating system.

An effective method of struggle with the phenomenon of the gal vanic corrosion of elements of electric circuits of the heating system is the integration in the heating system of the unit of polarity reversal of the output voltage of the output rectifier, the input of which is series-connected to the output of the output rectifier, and the output is series-connected to the resistance heating element.

The unit of polarity reversal allows to perform a periodic change of the polarity of current, that flows in the load circuit, in other words, ensures the operation of load circuits at the alternating current. Periodic change of the current polarity with a frequency of several dozens or hundreds Hz reduces dramatically the rate of electrochemical processes in current-conducting circuits and elements of the heating system, that increases the safety of the heating system due to the deceleration of corrosion processes in current- conducting circuits and deceleration of breakdown of electric insulation layers of current-conducting circuits and prevents an early failure of the heating system and extends its life.

The claimed invention is explained in drawings:

On Fig. 1 - structural electric drawing of the first variant of the claimed system of electric heating;

On Fig. 2 - structural electric drawing of the second variant of the claimed system of electric heating;

On Fig. 3 - structural electric drawing of the third variant of the claimed system of electric heating.

The system of electric heating, claimed by the first execution variant, the powered by AC mains of 1 frequency in the range of 50-1000 Hz, comprises at least one resistance heating element 2 and the electric shock protection device 3, series-connected between the contour of AC mains 1 and the resistance heating element 2. The claimed system of electric heating of the first variant of execution can work from industrial commercial AC mains of 50-60 Hz, and also from local autonomous AC mains with a frequency of 400-1000 Hz of movable facilities of ground, sea, underwater, air, space basing. The claimed heating system can use as the resistance heating element 2 film two-dimensional heating elements on the basis of a carbon fiber, electroconduetive films, heating cables, heating nets and clothes, band, bar and wire heaters, heating elements on the basis of current-conducting liquids, heating elements, specially designed for the heating of transparent or reflecting surfaces, for example, windows, windshields, mirrors and any other heating elements, the principle of actions of which is based on the heat generation w^rhen the electric current passes through the conductor having electric resistance.

The electric shock protection device 3 is made on the basis of at least one dividing transformer 4 that performs two main functions: reduction of the supply voltage to the safe extra low voltage value, for example, not higher than 42.4V as per the European standards (GOST lEC 60335-1-2008) and not higher than 30V as per the standards of USA, Canada, Japan; ensuring of galvanic isolation of electric circuits of AC supply industrial commercial mains or local supply electric circuits and load circuit (heat-generating resistant elements).

In order to provide the absence of the acoustic noise during the operation of a key element of the electric shock protection device 3, namely, the safe dividing transformer 4, it is necessary to bring out of the hearing by ears of a man and/or animal the frequency spectrum of the acoustic radiation signal, generated by the safe dividing transformer 4. From the state of art, it is known (GOST 12.2.024-87 Occupational safety standards system (OSSS). Noise. Power oil-immersed transformers. Norms and control methods), that low-frequency transformers during operation generate vibrations and acoustic noise on frequencies multiple of AC frequency, supplied to the transformer's input. With regard to the above mentioned, the biggest amplitude of the acoustic signal, generated by the transformer during its operation, corresponds usually to the second harmonic frequency value (double value) of the AC frequency, supplied to the transformer's input. If the value of AC frequency, supplied to the transformer's input, actuates the acoustic signal, the frequency spectrum of which lays out of frequency spectrum of hearing by ears, then such a transformer and devices, made on its basis, will be regarded by a man and/or animal as noiseless, in other words, as acoustically comfortable.

To ensure in the claimed system of electric heating a noiseless operation of the electric shock protection device 3, made on the basis of the safe dividing transformer 4_S it is necessary to choose the operational frequency of the safe dividing transformer 4 in such a manner that the frequency spectrum of the generated acoustic signal is higher or lower of the frequency spectrum of hearing by ears of a man and/or animal.

If peculiarities of the structural execution of the safe dividing transformer 4 and peculiarities of its electric operation modes allow it to generate the acoustic signal of a frequency, corresponding to odd values, starting from the first, of frequency harmonics of the supplying AC, then for the acoustic comfort for the man's ears it is necessary to choose the frequency value of the operation of the safe dividing transformer 4 lower than 20 Hz or higher than 20 000 Hz.

Levels of frequency-amplitude characteristics, perceived by man's ears, and also permissible norms of the acoustic pollution of residential and not residential rooms are determined in GOST 23337-2014 Noise. Methods of noise measurement in residential areas and in the rooms of residential, public and community buildings, and in GOST R ISO 8253-1-2012 Acoustics. Audiometric test methods. Part 1. Pure-tone air and bone conduction audiometry and in the internet at the URL address: http://www.ksp~ nisk.ru/page__919.himl .

If peculiarities of the structural execution of the safe dividing transformer 4 and peculiarities of its electric operation modes allow it to generate the acoustic signal at a frequency, corresponding to even values of frequency harmonics of supplying AC (starting from the second harmonic) then with regard to the value of the amplitude maximum of the second harmonic (double multiplicity of the frequency of the transformer's acoustic signal, generated during its operation, frequency of supplying AC), it is necessary to choose the frequency value of the operation of the safe dividing transformer 4 lower than 10 Hz or higher than 10 000 Hz.

From the practical point of view, for the realization of the claimed system of electric heating for the above-given example of execution the most rational is to choose the operational frequency of the safe dividing transformer 4 in the upper part of the frequency spectrum, ensuring its noiseless operation in the electric shock protection device 3 starting from 10 000 Hz and above.

The structure of the safe dividing transformer 4 can be realized as it was described in the RU patent for the invention no. 2074432 Matrix Transformer of in the RU patent for the invention No.2065631 Transformer and the method of its manufacturing, rightholders Vasilii Arsenevich Khabuzov, Vladimir Fedorovich Khudyakov.

Output circuit of the safe dividing transformer 4, operating at frequencies, ensuring acoustic comfort for users in a heated room, is connected directly to load, namely, to the resistance heating element 2.

Choice of a high operation frequency of the safe dividing transformer 4 is preferable as it has also an additional positive effect in the form of a significant decrease of weight, dimensions and labor intensity of its manufacturing and, respectively, a significant decrease of the weight and dimensions of the electric shock protection device 3, made on its basis.

The electric shock protection device 3 is additionally equipped with the generator 3, series-connected between the AC supply circuit 1 and the safe dividing transformer 4. With regard to the above mentioned, the input of the generator 5 is connected to AC supply mains 1 , and the output of the generator 5 is connected to the primary winding of the safe dividing transformer 4, the output winding of the safe dividing transformer 4 is connected to the resistance-heating element 2. The generator 5 generates alternating current, amplitude, form and frequency of which is required for the ensuring the noiseless operation mode of the dividing transformer 4.

The structure of the generator 5 can be implemented in accordance with any scheme, known from the state of art, for example, as described in the book of A.A. Bas, V.P. Milovzorov, A.K. Musolin "Sources of the secondary electric supply with the transformator-less input", publishing house "Radio and Svyaz", 1987, 27 p., fig. 2.4 or p. 57, fig. 2.28.

The operational frequency of the generator 5 is selected in such a manner that the frequency spectrum of the acoustic radiation signal, generated by the safe dividing transformer 4, is out of the hearing by ears of a man and/or animal.

The electric shock protection device 3 of the claimed structure as per the first execution variant can by completely or partially made in the form of an interior feature, for example, a picture.

The use of the safe dividing transformer 4 in the claimed heating system, operating at a high frequency, especially of the safe dividing transformer 4 of the matrix structure, allows to produce it in small dimensions and weights, and in different geometric forms, that allows easily adapt it to the interior of a heated room and easily integrate it in objects of the engineering and interior arrangement of the heated room, for example, in shelves, panel pictures, lamps, wall bracket lamps, floor lamps, supports, bedside tables, vases, sculptures, base moldings and so on.

The claimed heating systems as per the first execution variant, given in Fig. 1, operates as follows: the input of the generator 5 is powered by AC industrial commercial mains 1 with a frequency of 50-60 Hz. The generator 5 at its output generates alternating current with a frequency that ensures noiseless operation of the safe di viding transformer 4 that is included, along with the generator 5, into the electric shock protection device 3. AC current from the output of the generator 5 comes to the input, namely to the primary winding of the safe dividing transformer 4. The safe dividing transformer 4 transforms this voltage to the safe extra low voltage, for example, 3, 6, 12, 24, 30, 36, 42.4 Volts, that is supplied to the load circuit of the resistance heating element 2. When current passes through the resistance heating element 2, the thermal emission occurs, and the generated heat is used for the room heating.

Therefore, on the basis of the claimed invention an energy effective, electrically safe system of electrical heating with a noiseless, compact electric shock protection device 3, that allows to place it directly in heated rooms, was created.

The electric heating system, claimed by the second variant of execution, powered by AC mains 1 with a frequency in the range of 50-1000 Hz, is given on Fig.2 and contains at least one resistance heating element 2 and the electric shock protection device 3, series-connected between AC mains circuit 1 and the resistance heating element 2. The electric heating system, claimed as per the second variant, can work from AC industrial commercial mains of 50-60 Hz, and also from local autonomous AC supply networks with a frequency of 400-1000 Hz of fixed and movable facilities of ground, sea, underwater, air and space basing.

The claimed heating system can use as the resistance heating element 2 film two-dimensional heating elements on the basis of a carbon fiber, electroconductive films, heating cables, heating nets and clothes, hand, ^'bar and wire heaters, heating elements on the basis of current-conducting liquids, heating elements, specially designed for the heating of transparent or reflecting surfaces, for example, windows, windshields, mirrors and any other heating elements, the principle of actions of which is based on the heat generation when the electric current passes through the conductor having electric resistance.

The electric shock: protection device 3 is made on the basis of at least one dividing transformer 4 that performs two main functions: reduction of the supply voltage to the safe extra low voltage value, for example, not higher than 42.4V as per the European standards (GOST IEC 60335-1 -2008) and not higher than 30V according to the standards of USA, Canada, Japan; ensuring of galvanic isolation of electric circuits of AC supply industrial commercial mains, or local supply electric circuits and load circuit (heat-generating resistant elements).

In order to provide the absence of the acoustic noise during the operation of a key element of the electric shock protection device 3, namely, the safe dividing transformer 4, it is necessary to bring out of the hearing by ears of a man and/or animal the frequency spectrum of the acoustic radiation signal, generated by the safe dividing transformer 4. From the state of art it is known (GOST 12.2.024-87 Occupational safety standards system (OSSS). Noise. Power oil-immersed transformers. Norms and control methods), that low-frequency transformers during operation generate vibrations and acoustic noise on frequencies multiple of AC frequency, supplied to the transformer's input. With regard to the above mentioned, the biggest amplitude of the acoustic signal, generated by the transformer during its operation, corresponds usually to the second harmonic frequency value (double value) of AC frequency, supplied to the transformer's input. If the value of AC frequency, supplied to the transformer's input, actuates the acoustic signal, the frequency spectrum of which lays out of frequency spectrum of hearing by ears, then such a transformer and devices, made on its basis, will be regarded by a man and/or animal as noiseless, in other words, as acoustically comfortable. To ensure in the claimed system of electric heating a noiseless operation of the electric shock protection device 3, made on the basis of the safe dividing transformer 4, it is necessary to choose the operational frequency of the safe dividing transformer 4 in such a manner that the frequency spectrum of the generated acoustic signal is higher or lower of the frequency spectrum of hearing by ears of a man and/or animal.

Levels of frequency-amplitude characteristics, perceived by man's ears, and also permissible norms of the acoustic pollution of living and not living rooms are determined ill GOST 23337-2014 Noise. Methods of noise measurement in residential areas and in the rooms of residential, public and community buildings, and also in GOST R ISO 8253-1-2012 Acoustics. Audiometric test methods. Part 1. Pure-tone air and bone conduction audiometry and in the internet at the URL address: http:://www.ksp~ msk.ru/page _919html .

If peculiarities of the structural execution of the safe dividing transfomier 4 and peculiarities of its electric operation modes allow it to generate the acoustic signal at a frequency, corresponding to even values of frequency harmonics of supplying AC (starting from the second harmonic) then with regard to the value of the amplitude maximum of the second harmonic (double multiplicity of the frequency of the transformer's acoustic signal, generated during its operation, frequency of supplying AC), it is necessary to choose the frequency value of the operation of the safe dividing transformer 4 lower than 10 Hz or higher than 10 000 Hz.

The structure of the safe dividing transformer 4 can be realized as it was described in the variant 1 of the claimed electric heating system.

The electric shock protection device 3 in the second variant of execution is additionally equipped with the generator 5, series-connected between AC mains circuit 1 and the safe dividing transformer 4 and at least one output rectifier 6, series-connected between the safe dividing transformer 4 and the resistance heating element 2, at that the input of the generator 5 is conn ected to AC mains 1, and the output of the generator 5 is connected to the primary winding of the safe dividing transformer 4. The output winding of the safe dividing transformer 4 is connected to the input of the output rectifier 6, and the output of the output rectifier 6 is connected to the resistance heating element 2.

Therefore, the output circuit of the safe dividing transformer 4, operating at frequencies that ensure the acoustic comfort for users, staying in the heated room, is connected to the load through the output rectifier 6,

The structure of the output rectifier 5 can be realized as described in the book of A.A. Bas, V.P, Milovzorov, A.K. Musolin "Sources of the secondary electric supply with the transformerless input", publishing house "Radio and Svyaz", 1987, 26 p., fig. 2.2 b.

The second variant of invention is designed for cases when the safe dividing transformer 4 is at a significant distance from the resistance heating element 2 and connecting wires between the output of the safe dividing transformer 4 have big length due to which fact they have increased value of own parasitic inductance, at that the resistance heating element 2 can be made as a two-dimensional film heating element with a. low parasitic inductance; or, in the second case, when connecting wires between the output of the safe dividing transformer are longer and due to this fact they have a high value of the parasitic inductance, and the resistance heating element 2 is of a cable, band or reel type with a high value of parasitic inductance.

High level of the inductive component of the electric heating system load circuit prevents the current from passing through the heating element 2. At the same time, due to the reduction of the value of current, passing through the resistance heating element 2, the level of generated themial power falls down, and the thermal efficiency of the heating system decreases, To compensate insufficient heating of the resistance heating element 2 in heating system with a high value of the parasitic inductance and a high value of heating alternating current, It is necessary either increase the voltage value in the load circuit, that contradicts with the requirements of the system electric safety, or switch to the supply of the heating element 2 with rectified (direct) current.

To solve this issue in the second variant of the invention execution in the electric shock protection device 3 between the output of the safe dividing transformer 4 and the circuit of the resistance heating element 2 at least one output rectifier 6, that transforms alternating current from the output of the safe dividing transformer 4 to rectified (direct) current, that comes to the load circuit, is connected.

At that, the value of the inductive component of connecting wires and the resistance heating element 2 does not matter as it is known that the presence of the inductive component in a current-conducting circuit does not obstruct the flow⁷ of rectified (direct) current. Therefore, the construction of the second variant of the electric heating system allows to exclude limitations on the special arrangement of the electric shock protection system operating at high frequencies (more than 1000 Hz), and constructions of resistance heating elements 2. With regard to the above mentioned, the acoustic comfort of the heating system is maintained due to the noiseless operation of the safe dividing transformer 4, and the energy effectiveness of the heating system due to the possibility of arrangement of the electric current protection device 3 on the basis of the safe dividing transformer 4, and also current-conducting circuits inside a heated room.

The generator 5 generates alternating current, amplitude, form and frequency of which is required for the ensuring the noiseless operation mode of the dividing, transformer 4.

The operational frequency of the generator 5 can be realized so that the frequency spectrum of the acoustic radiation signal, generated by the safe dividing transformer 4, is out of the hearing by ears of a man/or animal.

The structure of the generator 5 can be realized as it was described in the variant 1 of the claimed heating system.

The electric shock protection device 3 of the claimed structure as per the second execution variant can be completely or partially executed in the form of an interior feature, for example, of a picture.

The claimed heating systems as per the second execution variant, given in Fig. 2, operates as follows: the input of the generator 5 is powered by AC industrial commercial mains 1 with a frequency of 50-60 Hz, The generator 5 at its output generates alternating current with a frequency that ensures noiseless operation of the safe dividing transformer 4 that is included, along with the generator 5, into the electric shock protection device 3. AC current from the output of the generator 5 comes to the input, namely to the primary winding of the safe dividing transformer 4. The safe dividing transformer 4 transforms this voltage to the safe extra iow voltage, for example, 3, 6, 12, 24, 30, 36, 42.4 Volts, that is supplied to the input of the output rectifier 6 that transforms the coming to its input alternating current into rectified (direct) current, flowing further to the load circuit, namely, to the resistance heating element 2. When current passes through the resistance heating element 2, the thermal emission occurs, and the generated heat is used for the room heating.

The claimed system of electric heating as per the second execution variant, having all advantages, described above in the variant 1, allows to use in the heating system resistance heating elements 2, that have high value of parasitic inductance of the current-conducting circuit due to its . structure, that expands the area of possible application of the claimed heating system.

The third variant of the claimed system of electric heating, given on Fig.3 is the most reasonable for the installation in wet rooms. In such rooms there is a hazard of accelerated electrochemical breakdown of current- conducting circuits and elements of the electric heating system what leads to the accelerated breakdown of current-conducting circuits and their insulation in areas of corrosion, resulted in an early failure of the heating system.

The electric heating system, claimed by the third variant of execution, powered by AC mains 1 with a frequency in the range of 5Θ-1000 Hz, is given on Fig.3 and contains at least one resistance heating element 2 and the electric shock protection device 3, series-connected between AC mains circuit 1 and the resistance heating element 2. The electric heating system, claimed as per the third variant, can work from AC industrial commercial mains of 50-60 Hz, and also from local autonomous AC supply mains with a frequency of 400- 1000 Hz of fixed and movable facilities of ground, sea, underwater, air and space basing.

As the resistance heating component 2 in the claimed heating system as per the third execution variant, resistance heating elements, the structure of which is described above in variants one and two of the present invention, can be used. To struggle with the galvanic corrosion of elements of electric circuits of the resistance heating element 2 in the third variant of the electric heating system, the electric shock protection system is additionally equipped with the generator 5, series-connected between AC mains circuit 1 and the safe dividing transformer 4, and series-connected between the safe dividing transformer 4 and the resistance heating element 2 at least one output rectifier 6 and at least one unit of polarity reversal 7 of the output voltage of the output rectifier 6,

At that the input of the generator 5 is connected to AC mains, the output of the generator 5 is connected to the primary winding of the safe dividing transformer 4, the output winding of the safe dividing transformer 4 is connected to the input of the output rectifier 6, the output of which is connected to the input of the unit of polarity reversal 7 of the output voltage of the output rectifier 6. The output of the unit of polarity reversal 7 is connected to the resistance heating element 2.

The operational voltage of the generator 5 is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer 4 is out of hearing by ears of a man and/or animal.

The unit of polarity reversal 7 allows to perform a periodic change of the polarity of current, that flows in the circuit of the resistance heating element 2, in other words, ensures the operation, of load circuits at the alternating current. Periodic change of the current polarity with a frequency of several dozens or hundreds Herz reduces dramatically the rate of electrochemical processes in current-conducting circuits and elements of the heating system, that increases the safety of the heating system due to the deceleration of corrosion processes in current-conducting circuits and deceleration of breakdown of electric insulation layers of current-conducting circuits, and prevents an early failure of the heating system and extends its life. The electric shock protection device 3 of the claimed structure as per the second execution variant can be completely or partially executed in the form of an interior feature, for example, of a picture.

The structure of the safe dividing transformer 4, generator 5, output rectifier 6 can be executed in the same manner as it was described in the variant two of the claimed invention.

The structure of the unit of the polarity reversal 7 of the output voltage of output rectifier 6 in the third variant of realization of the claimed invention can be executed, as given on Fig.1 in the RF patent for invention No.2510864 Voltage bridge transformer, the date of priority 07.12,2012, the date of publishing 10.04.2014.

The claimed heating system as per the third variant of execution, given on Fig.3, works as follows: the input of the generator 5 is powered by industrial commercial AC mains 1, with a frequency of 50-60 Hz. The generator 5 at its output generates AC with a frequency, ensuring the absence of acoustic noise during the operation of the safe dividing transformer 4, included together with the generator 5 into the electric shock protection device 3. AC electric current from the output of the generator 5 comes to the input, namely, to the primary winding of the safe dividing transformer 4. The safe dividing transformer 4 transforms this voltage to the safe extra low voltage, for example, 3, 6, 12, 24, 30, 36, 42 Volts, that is supplied to the input of the output rectifier 6 that transforms incoming alternating current into rectified (direct) current. Rectified (direct) current, flowing further to the input of the unit of polarity reversal 7 of the output voltage of the output rectifier 6. The unit of polarity reversal 7 executes periodic change of the current polarity, flowing in the circuit of the resistance heating element 2, decelerating the process of galvanic corrosion (degradations) of current- conducting circuits and isolation of the resistance heating element 2. The electric shock protection device 3 in the electric heating system in all three variants of execution can be structurally executed either in the form of a single one-piece structure or in the form of structurally completed individual functional units 4, 5, 6, 7 that can he mounted at a distance from each other.

Claims

1. The electric heating system, powered by AC mains with a frequency in the range of 50-1000 Hz, comprising at least one resistance heating element and the electric shock protection device, series-connected between the AC mains circuit and the resistance heating element, executed on the basis of at least one safe dividing transformer c h a r a c t e r i z e d by the fact, that the electric shock protection device is additionally equipped with the generator, series-connected between the AC mains circuit and safe dividing transformer; furthermore, the input of the generator is connected to the AC mains, the output of the generator is connected to the primary winding of the safe dividing transformer, and the output winding of the safe dividing transformer is connected to the resistance heating element; with regard to the above mentioned, the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal.

2. The electric heating system of claim 1, in which electric shock protection device can be completely or partially executed in the form of a room interior feature, for example, of a picture,

3. The electric heating system, powered by AC mains with a frequency in the range of 50-1000 Hz, comprising at least one resistance heating element and the electric shock protection device, series-connected between the AC mains circuit and the resistance heating element, executed on the basis of at least one safe dividing transformer c h a r a c t e r i z e d by the fact, that the electric shock protection device is additionally equipped with the generator, series-connected between the AC mains circuit and safe dividing transformer, and at least one output rectifier, series-connected between the safe dividing transformer and resistance heating element; with regard to the above mentioned, the input of the generator is connected to the AC mains, the output of the generator is connected to the primary winding of the safe dividing transformer, and the output winding of the safe dividing transformer is connected to input of the output rectifier, and the output of the output rectifier is connected to the resistance heating element, at that the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearing by ears of a man and/or animal.

4. The electric heating system of claim 3, in which electric shock protection device can be completely or partially executed in the form of a room interior feature, for example, of a picture,

5, The electric heating system, powered by AC mains with a frequency in the range of 50-1000 Hz, comprising at least one resistance heating element and the electric shock protection device, series-connected between the AC mains circuit and the resistance heating element, executed on the basis of at least one safe dividing transformer c h a r a c t e r i z e d by the fact, that the electric shock protection device is additionally equipped with the generator, series-connected between the supply network circuit and the safe dividing transformer, and series-connected between the safe dividing transformer and resistance heating element at least one output rectifier and at least one unit of polarity reversal of output voltage of the output rectifier, at that the input of the generator is connected to AC mains, the output of the generator is connected to the primary winding of the safe dividing transformer, the output winding of the safe dividing transformer is connected to the input of the output rectifier, the output of which is connected to the input of the unit of polarity reversal of output voltage of the output rectifier, the output of which is connected to the resistance heating element, at that the operational frequency of the generator is selected in such a manner that the frequency spectrum of the acoustic radiation signal generated by the safe dividing transformer, is out of hearings by ears of a man and/or animal.

6. The electric heating system of claim 5, in which electric shock protection device can be completely or partially executed in the form of a room interior feature, for example, of a picture.