RU230865U1 - Shungite electric heating element for heating equipment - Google Patents

Abstract

The utility model relates to the field of electrical engineering, namely to non-metallic electric heating elements, and is intended for use in the designs of heaters, convectors and/or radiators for heating residential, mobile and industrial premises. The shungite electric heating element for heating equipment includes a base (1) made on the basis of electrically conductive shungite with the possibility of connection to a source of electric current, and thermal insulation (2), wherein the base (1) is made in the form of a plate of solid medium-carbon shungite, and the thermal insulation (2) is made of a high-temperature mixture. The technical result of the utility model consists in increasing the resistance of the shungite electric heating element for heating equipment to the effects of high temperatures up to 600°C. 6 clauses, 4 figs.

Description

[01] Field of technology

[02] The utility model relates to the field of electrical engineering, namely to non-metallic electric heating elements, and is intended for use in the construction of heaters, convectors and/or radiators for heating residential, mobile and industrial premises.

[03] State of the Art

[04] Ceramic heating elements of the PTC and NTC types are widely known and are used in various devices. Currently, such heating elements are used in forced-air convectors, heat guns, where they are placed between the metal plates of the air heater. However, ceramic heating elements do not provide sufficient heating of large metal sections of heating equipment, as they have temperature limitations. Ceramic heating elements are also quite fragile, as a result of which they quickly become inoperative as a result of mechanical impact. In addition, the manufacture of ceramic heating elements in the form of plates with the required parameters is a complex and labor-intensive process, which also requires the application of an expensive electrocontact coating.

[05] A conductive composition described in patent for invention No. 2653176, 07.05.2018, is known, which includes shungite powder, as well as a method for manufacturing heating elements based on it. The used conductive composition has a number of disadvantages, since shungite powder is mixed with expensive film-forming binders, solvents and hardeners. Also, when strongly heated, the formed thin film located on the dielectric substrate can easily crack, which will cause a lack of contact. Another significant disadvantage is the complexity of producing an electric heating element from the said composition, which requires alternate application of layers of the said conductive composition.

[06] The prior art also includes a shungite heating element described in the Russian Federation patent for IM RU64463, 27.06.2007. This shungite heating element is a shungite plate built into a non-standard design heater. At the same time, the said shungite heating element only functions as a screen (emitter), which does not have the ability to be connected to a source of electric current.

[07] Thus, there is a need to produce a non-metallic electric heating element for standard heating equipment that provides not only high heat transfer rates, but also ease of manufacture.

[08] The closest analogue of the claimed technical solution is the shungite electric heating element, presented in the Russian Federation patent PM RU54708, 10.07.2006. The shungite electric heating element includes a base made of an electrically conductive mixture based on electrically conductive shungite with the ability to be connected to a source of electric current, and thermal insulation.

[09] The disadvantage of this device is that its base is made of an electrically conductive mixture consisting of liquid glass, an inert filler and shungite itself, which can lead to the destruction of the electric heating element during its operation when heated to high temperatures (the maximum heating temperature of the electric heating element made of this electrically conductive mixture is 400°C). Also, in the design of this electric heating element, the base made of an electrically conductive mixture based on electrically conductive shungite does not have direct contact with the metal elements (sections) of the heating equipment, which can lead to a decrease in heat transfer from the electric heating element.

[010] Thus, the technical problem that the claimed utility model is aimed at solving is the insufficiently high technical characteristics of known shungite electric heating elements intended for use in the design of heating equipment.

[011] Disclosure of the essence of the utility model

[012] The technical result of the utility model consists in increasing the resistance of the shungite electric heating element for heating equipment to the effects of high temperatures up to 600°C.

[013] The durability of a device should be understood as the ability to maintain functional properties under given conditions.

[014] Additional advantages of the utility model include the low amount of electricity consumed by the heating equipment, the design of which includes the declared shungite electric heating element, as well as the ease of manufacturing the electric heating element.

[015] The specified technical result is achieved due to the fact that the shungite electric heating element for heating equipment includes a base made from electrically conductive shungite with the possibility of connecting to a source of electric current, and thermal insulation, wherein the base is made in the form of a plate of solid medium-carbon shungite, and the thermal insulation is made from a high-temperature mixture.

[016] In particular cases of implementation of the utility model:

[017] - the contact surface of the base contains an electrically conductive coating,

[018] - a high-temperature silicate sealant was used as a high-temperature mixture,

[019] - the high-temperature mixture contains inclusions of quartz sand and/or glass fiber,

[020] - the size of the base sides is from 7.0 to 15.0 mm, [021] - the carbon content in medium-carbon shungite is from 29.0 to 70.0 wt. %,

[022] - the thickness of the plate base is from 2.0 mm to 10.0 mm.

[023] Shungite, used for the manufacture of the claimed electric heating element, is a natural material and has a unique chemical composition, providing high thermal conductivity properties of the electric heating element made on its basis. As is known from the state of the art, shungite is a Precambrian rock, occupying an intermediate position between graphite and anthracite. The conductivity of shungite is due to graphene packs, which are collected into larger globules, then form large conductive layers between non-conductive inclusions, consisting, as a rule, of quartz [I.V. Antonets, E.A. Golubev, V.G. Shavrov, V.I. Shcheglov. INFLUENCE OF STRUCTURAL PARAMETERS OF SHUNGITE ON ITS ELECTRICALLY CONDUCTIVE PROPERTIES // JOURNAL OF RADIO ELECTRONICS, ISSN 1684-1719, - 2017. - No. 5. - P. 4]. Shungite carbon contains fullerene-like regular structures in an amount from 0.0001 to 0.001 wt. %. Shungite has the following properties: electrical conductivity coefficient - (1-3) × 10 ³ S/m; thermal conductivity coefficient - 3.8 W/m⋅K, average value of the coefficient of thermal expansion in the temperature range from +20 to +600 °C - 12⋅10 ^-6 K ^-1 , calorific value - 7500 kcal/kg. [https://ru.wikipedia.org/wiki/шунгит].

[024] Medium-carbon shungite used in the claimed technical solution for the manufacture of a base in the form of a plate from a solid piece of it contains carbon in an amount from 29.0 to 70.0 wt. %, that is, it belongs to the classical type of shungite (shungite II or shungite III) [I.V. Antonets, E.A. Golubev, V.G. Shavrov, V.I. Shcheglov. INFLUENCE OF STRUCTURAL PARAMETERS OF SHUNGITE ON ITS ELECTRICALLY CONDUCTIVE PROPERTIES // JOURNAL OF RADIO ELECTRONICS, ISSN 1684-1719, 2017. No. 5. P. 11], [Filippov M.M. Shungite-bearing rocks of the Onega structure. // Petrozavodsk: Karelian Scientific Center of the Russian Academy of Sciences, - 2002. - P. 30-35]. The carbon component and its distribution in the mineral matrix provide high electrical conductivity of the heating element. With the specified carbon content, the content of silicate quartzite matrix in the form of silicon oxide (SiO2) in medium-carbon shungite is a significant part, which increases its resistance, preventing the destruction of the electric heating element when exposed to high temperatures (up to 600 °C).

[025] The presence of thermal insulation made of high-temperature material applied along the perimeter of the base of the electric heating element helps to preserve and concentrate the heat obtained from the passage of electric current inside the shungite base and transfer most of the heat (up to 95-98%) directly to the metal elements of the heating equipment through the contact surface of the electric heating element. In addition, the presence of the said thermal insulation made of a high-temperature mixture additionally contributes to the resistance of the heating element to the effects of high temperatures up to 600°C.

[026] The electric heating element in accordance with the claimed utility model comprises a flat base in the form of a plate made of solid (monolithic) shungite with a thickness of, preferably, from 2.0 mm to 10.0 mm. The shape of the electric heating element in the form of a plate ensures uniform distribution and transfer of heat. The said preferred thickness of the electric heating element ensures a high heating rate, lower electrical resistance compared to a heating element of greater thickness, as well as the possibility of arranging the electric heating element between standard sections of heating equipment, in particular, a convector or radiator. With a plate thickness of less than 2.00 mm, the risk of damage to the electric heating element as a result of external mechanical impact increases, in addition, an element less than 2.0 mm thick will have insufficient thermal capacity.

[027] Brief description of drawings

[028] The utility model is illustrated by figures, where

[029] Fig. 1 shows a top view of the claimed shungite electric heating element,

[030] Fig. 2 shows a side view in section of the claimed shungite electric heating element,

[031] Fig. 3 shows a photographic image of the claimed shungite electric heating element without an electrically conductive coating,

[032] Fig. 4 shows a photographic image of shungite electric heating elements containing an electrically conductive coating on the contact surface of the base.

[033] The elements are designated on the figure by the following positions:

1 base;

2 thermal insulation;

3 - conductive coating.

[034] Implementation of a utility model

[035] The claimed shungite electric heating element consists of a flat base (1) made of a solid (monolithic) natural mineral of medium-carbon shungite (not elite, classic shungite II or shungite III) with a carbon content (C) from 29.0 to 70.0 wt. %, and thermal insulation (2) (Fig. 1).

[036] It is preferable to use shungite mined at the Zazhoginskoye deposit and Prionezhye in the Republic of Karelia, Russian Federation, which has the following chemical composition (wt. %): SiO ₂ - 57.0 - 57.5; C - 29.0 - 30.0; Al ₂ O ₃ - 4.0; H ₂ O (cryst.) - 1.7 - 2.3; K ₂ O -1.5; Fe ₂ O ₃ - 1.49 - 2.5; MgO - 1.1 - 1.2; S -1.1 - 1.2; CaO -0.3 - 0.6; TiO ₂ -0.2; Na ₂ O - 0.2; MnO - 0.15.

[037] The base (1) made of solid medium-carbon shungite is made in the form of a plate in the shape of a square or other geometric figure with the size of the sides from 7.0 mm to 15.0 mm and the thickness from 2.0 mm to 10.0 mm. The preferred size of the sides of the electric heating element made in the shape of a square is 10.0 mm. The preferred size of the thickness of the base (1) of the electric heating element for heating equipment in the form of a steel convector is from 5.0 to 10.0 mm, and for heating equipment made of non-ferrous metals, in particular, an aluminum or copper convector - from 2.0 to 5.0 mm.

[038] Thermal insulation (heat jacket) (2) made of a high-temperature mixture is applied along the perimeter of the base (1) of the electric heating element, i.e. along its lateral sides. The said high-temperature mixture is a hardened mixture of a high-temperature silicate sealant used for furnaces (for example, the PENOSIL brand manufactured by Wolf Group, Estonia). This mixture may additionally contain inclusions of quartz sand or fiberglass in order to increase strength and improve the insulating characteristics. The said mixture is applied to the lateral sides of the base (1) of the electric heating element in a liquid paste-like state with subsequent hardening. The thickness of the thermal insulation (2) corresponds to the thickness of the base (1) of the electric heating element and may be from 2.0 to 10.0 mm, the height of the thermal insulation layer (2) may be from 2.0 to 5.0 mm along the perimeter of the base (1) of the electric heating element (Fig. 2).

[039] The contact (end) surfaces of the base (1) of the electric heating element may contain an electrically conductive coating (3) in the form of a metal layer, which may be applied either by galvanic means or by rubbing the metal against the surface (Fig. 4).

[040] Shungite electric heating elements in accordance with the declared utility model can be manufactured both manually and on automated production lines.

[041] The claimed device can be used in various heating equipment (convector, radiator, heater) both in self-assembly and in industrial production of the said equipment. For this, the claimed shungite electric heating element is clamped between sections of the heating equipment in the form of metal pipes, strips or plates consisting of aluminum, copper or metal alloy (steel). The sections are pulled together with common insulated pins along the entire length of the equipment. A safe low-voltage direct or alternating voltage of 1 V or more and a current of 3 A or more from an adjustable power source are supplied to the extreme sections, after which the shungite electric heating elements are heated, which in turn transfer heat to the metal elements of the heating equipment. At the same time, the declared electric heating element in the form of a small plate with a thickness of 2.0 to 10.0 mm gives off a large amount of heat due to the unique electrically conductive properties of shungite (electrical conductivity coefficient - (1-3) × 10 ³ S/m; thermal conductivity coefficient - 3.8 W/m⋅K, the average value of the thermal expansion coefficient in the temperature range from +20 to +600 ° C is 12⋅10 ^-6 K ^-1 , calorific value is 7500 kcal/kg). The electrical connection of the sections can be series, parallel and series-parallel. With a parallel connection, the power supply is up to 5 V, with a series connection - from 12 V. Current consumption will depend on the voltage and total resistance. Simple voltage or current adjustment of the power supply and / or thermostat makes it possible to constantly maintain the required temperature. The source of electricity can be any power supply units, step-down and step-up transformers, chemical and solar batteries, accumulators, wind generators, low-voltage generators, diesel and gasoline generators, converters that convert high-voltage voltage into low-voltage current.

[042] Heating equipment, in the design of which the declared heating elements are used, heats up to the required temperature at a high speed. The maximum operating temperature of the shungite electric heating element is 600°C. Several declared heating elements can be used in the heating equipment, while the recommended number of electric heating elements per section of the heating equipment is 2 pieces. The more electric heating elements are used in the heating equipment, the less will be the amount of electricity consumed.

[043] Below are presented experimental data obtained as a result of using heating equipment, the design of which includes the declared shungite electric heating elements, as well as the closest analogue.

[044] Example 1. The design of the aluminum convector used the declared shungite electric heating elements in the form of a square with a thickness of 2.0 mm and a side length of 9.0 mm in the amount of 2 pieces per section of standard size 500 x 500 mm. The carbon content in shungite is 70.0 wt.%. The specified equipment was heated to a temperature of 70°C (the temperature measured at the air flow outlet at the top point), while the heating of the electric heating elements reached 120°C. The heating time was 4 minutes. The initial average temperature in the room was 18°C. Electric power consumption was 200-250 W. No damage to the shungite electric heating elements was detected.

[045] Example 2. The design of the steel convector used the declared shungite heating elements with a thickness of 7.0 mm and a side length of 12.0 mm in the amount of 2 pieces per section of standard size 500 x 550 mm. The carbon content in shungite is 50.0 wt.%. The specified equipment was heated to a temperature of 70°C (the temperature measured at the air flow outlet at the top point), while the heating of the electric heating elements reached 140°C. The heating time was 7 minutes. The average temperature in the room before heating the equipment was 18°C. Electric power consumption was 250-300 W. No damage to the shungite electric heating elements was detected.

[046] Example 3. The design of the copper convector used the declared shungite electric heating elements in the form of a square with a thickness of 5.0 mm and a side length of 10.0 mm in the amount of 2 pieces per section of the standard size of 500 x 500 mm. The carbon content (C) in shungite is 29.0 wt.%. The tests were carried out outdoors in cold weather at minus 30°C. The specified equipment was heated to a temperature of 40°C (the temperature measured at the air flow outlet at the top point), while the heating of the electric heating elements reached 600°C. The heating time was 9 minutes. The power consumption was 350-400 W. No damage to the shungite electric heating elements was detected.

[047] Example 4. The design of the copper convector used electric heating elements in accordance with the closest analogue. The carbon (C) content in shungite is 29.0 wt.%. The specified equipment was heated to a temperature of 30°C (the temperature measured at the air flow outlet at the top point), while the heating of the electric heating elements reached 400°C. The tests were carried out outdoors in cold weather at minus 30°C. The heating time was 20 minutes. Electricity consumption was 600-700 W.

[048] Thus, the claimed shungite electric heating element is resistant to heating up to 600°C compared to the closest analogue (maximum operating heating temperature 400°C), ensures a reduction in electricity consumption, as well as ease of manufacture of the said element from the natural material shungite.

Claims (5)

1. A shungite electric heating element for heating equipment, comprising a base (1) made on the basis of electrically conductive shungite with the possibility of connection to a source of electric current, and thermal insulation (2), characterized in that the base (1) is made in the form of a plate with a thickness of 2.0 to 10.0 mm from solid medium-carbon shungite with a carbon content of 29.0 to 70.0 wt. %, and the thermal insulation (2) is made of a high-temperature mixture. 2. A shungite electric heating element for heating equipment according to paragraph 1, characterized in that the contact surface of the base (1) contains an electrically conductive coating (3). 3. A shungite electric heating element for heating equipment according to paragraph 1, characterized in that a high-temperature silicate sealant is used as the high-temperature mixture. 4. A shungite electric heating element for heating equipment according to paragraph 1, characterized in that the high-temperature mixture contains inclusions of quartz sand and/or fiberglass. 5. A shungite electric heating element for heating equipment according to paragraph 1, characterized in that the size of the sides of the base (1) is from 7.0 to 15.0 mm.