RO123467B1 - Heating resistor - Google Patents

Abstract

The invention relates to a heating resistor for achieving an average temperature of 500°C at the most, to be employed in the field of thermotechnics. According to the invention, the resistor consists of a rectangular ceramic body (1) made of a non-hygroscopic material having a porosity of 0% by volume, inside which there is machined an orifice confined by a rectangular wall (a) wherein there is mounted a resistance subassembly (A) attached between two micanite sheets (2), the resistance subassembly (A) comprising a first micanite support (3) on which a Kanthal D. wire (4) is wound and a second micanite support (5) , the ends of the wire (4) being insulated by means of the two micanite sheets (2) between which the resistance subassembly (A) is mounted, the supply with electric current being achieved by two flexible electric cables (8) with double silicone insulation (9), the Kanthal D. wire being connected at the ends so that the non-insulated ends thereof are attached between the two micanite insulating sheets (2), the ceramic body (1) having its ends coated with a thermally resistant adhesive (10).

Description

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RO 123467 Β1

The invention relates to an electric resistance of heating of medium temperatures, intended to operate at temperatures of maximum 500 ° C, resistance that is used in the field of thermotechnics.

There are known electrical resistors that use ceramic materials or hard glass as electrical insulating material. The heating elements are arranged inside these ceramic materials or are inserted through holes in the rigid body of the insulating material. This type of electrical resistors implies a high energy consumption, they have a heavy manufacturing technology when the execution precision is desired. Also, due to the contact with the air, oxidation of the heating element can occur, especially in an average operating time.

From the patent RO 85804 is known an electrical resistance that works at temperatures up to 1000 ° C, consisting of a ceramic body, which has two longitudinal holes inside which the heating element is inserted, around which a frost is arranged around it. glass used at the same time as electrical insulator, thermal transfer table, sealing and fixing table, at the end the ceramic body having a cement layer. The connection with the power supply is made by two Cu conductors, around which, on a portion of them, a fluid glass glaze is deposited.

It is known, from patent RO 81149, an electric heating resistor made up of a heating element welded by two Cu conductors, which make the connection with the control circuit, the electrical insulation being made up of a glass wire, wrapped around the heating element. and around the two conductors, and solidarized to the two conductors by an adhesive, in another constructive variant, the electrical insulation is made from a tube of glass yarn fabric, a tube solidarized at its ends by heating and melting the wires. glass.

From a constructive point of view, all types of heaters already existing on the market are made up of two main parts; a ceramic body made of hydroscopic material, with porosity you. 30% and a resistance subassembly. The resistance is made of wire with a circular section, spiraled to a diameter of 3 mm, resistance which is reinforced with thermal insulating sand, and the openings are blocked with refractory adhesive. The protection against electric shocks is provided by the basic insulation.

The known electrical resistances have the disadvantage of the heat losses, due to the existence of a single layer of thermal insulator, they are fragile from the constructive point of view, they have a high thermal inertia, which implies a high energy consumption, it has a sensitivity to humidity, possibility of breaking the wire at electric shocks, because the insulating material can be moved, there is the possibility of corrugations due to the thermal deformation, if the covering surfaces of the heating element are not thick enough.

The technical problem solved by the invention consists in the additional insulation of the conductive parts and the protection against electric shocks, and eliminates the aforementioned disadvantages, by achieving an electric heating resistor operating at temperatures of up to 500 ° C, which is constituted by a ceramic body made of non-hygroscopic material, with porosity. 0%, inside which is mounted a resistance subassembly that is caught between two plates of micanite, the resistance subassembly being composed of a first support of micanite on which is wrapped a wire of Kanthal D wire and a second support from micanite, the ends of the wire being insulated by the two plates of micanite between which the subassembly is arranged, the power supply being made by two flexible electrical cables having double silicone insulation, the connection to the ends of the wire by Kanthal being made so that the ends are desolated stuck between the two insulating plates of micanite, the ceramic body having the ends plugged with a heat-resistant adhesive.

RO 123467 Β1

The electric resistance, according to the invention, is used in the field of thermotechnics and 1 has the following advantages:

- double protection against electric shocks (insulation class 2) 3

- increased safety in operation;

- low thermal inertia, which implies low energy consumption; 5

- good control of the thermostat;

- the average operating time is high due to the non-oxidation of the heating element 7 which is not in contact with the air;

- has a simple construction, the installation, maintenance and operation are easy, 9

- high thermal and energy efficiency, due to a suitable thermal insulation.

In the following, an embodiment of the invention is shown, in connection with FIG. 11 1 ... 10, which represents:

FIG. 1, front view and partially section of the electric heating resistor; 13

FIG. 2, a side view of the electrical resistance of fig. 1;

FIG. 3, front view of the first support for Kanthal D wire; 15

FIG. 4, the detail D of FIG. 3;

FIG. 5, front view of the second support for the Kanthal wire; 17

FIG. 6, front view of the resistance subassembly;

FIG. 7, view of the insulating plate; 19

FIG. 8, the resistance subassembly mounted on the insulating plate;

FIG. 9, side view and section of the ceramic body; 21

FIG. 10, staple section.

The electric heating resistor, according to the invention, which operates at temperatures 23 up to 500 ° C, consists of a ceramic body 1 of rectangular shape, which has longitudinally practiced a cutting of approximately rectangular shape, body 25 which is made from a non-hygroscopic material, with porosity you. 0%, for example cordierit. Inside the cutout a, a subassembly of resistance A is mounted, which is attached between two 27 plates of micanite 2. The subassembly of resistance A is composed of a first support 3, of rectangular form, made of micanite, On the lateral surfaces of the length, the support 3 has 29 holes b holes, 0.5 mm deep, on which is a wire 4 wire of Kanthal D. The support 3 has machined at the ends some holes o through the wire 4 and a 31 hole d. Near the support 3 is placed the second support 5, made of micanite, through the holes c practiced and in this support passing the wire 4 of wire by Kanthal D, which mechanically fastens the supports 33. The two supports 3 and 5 are joined and mounted between two insulating plates 2, from micanite, the assembly being solidarized by the staples 6, staples that penetrate into the holes d 35

The ends of the wire 4 are connected by the two crimping 7 and are insulated by the two micanite plates 2 between which the subassembly is arranged A. The supply of the electrical resistance 37 is made by two flexible electrical cables 8, which are insulated with double silicone insulation 9. 39

After mounting the subassembly A in the cutout a, the ends of the ceramic body 1 are clogged with a heat-resistant silicone adhesive 10

The electrical resistance, according to the invention, is a class II device, in which the protection against electric shocks is provided not only by the basic insulation made by the 43 two micanite plates 2, but also by the ceramic body 1, made of cordierite, a material non-hydroscopic, respectively, the heat-resistant adhesive 10, which constitutes the double insulation of the apparatus 45.

Claims (5)

1 Claim 3 The electrical heating resistance, consisting of a ceramic body and a resistance assembly made of wire with a circular section that is thermally insulated, the openings 5 of the ceramic body being blocked with adhesive, characterized in that, in order to operate at temperatures of maximum 500 ° C, it is constituted by a ceramic body (1), of 7 rectangular shape, made of non-hydroscopic material, with porous vol. 0%, inside which is worked a rectangular hole (a) in which a subassembly is mounted 9 resistance (A) which is caught between two plates of micanite (2), the resistance assembly (A) being made up of a first support (3) of the micanite on which a wire (4) of 11 Kanthal wire is wrapped (D) ) and a second support (5) from the micanite, the ends of the wire (4) being insulated by the two plates of micanite (2) between which is the subassembly (A), the supply of the electrical resistance 13 being made by two electrical cables (8). ) flexible having a double silicone insulation (9), the ends of the Kanthal wire being connected so that the disassembled ends of it 15 are connected between the two insulating plates (2) of micanite, the ceramic body (1) having the ends blocked with a heat-resistant adhesive (10).