RU2802460C1 - Electric heater and method of its production - Google Patents

Abstract

FIELD: heating systems.

SUBSTANCE: invention is related to sectional heaters and heating systems using electric heaters and can be used for both primary and secondary heating of residential, public and industrial premises - when designing electric heaters with a rated power not exceeding 3 kW. The technical result is achieved by the fact that the section of the electric heater consists of a body made of steel sheets of corrugated board with a thickness of 0.8 to 1.2 mm, rigidly fixed on aluminium profiles so that the end sides of the section are the sides of the profiles, a heating element made of low-carbon steel wire with a diameter from 0.8 to 1.5 mm, wound in a spiral with a pitch of 2 to 3 mm, located in turns over the entire area of the section with a distance of adjacent turns from 10 to 40 mm, a temperature sensor located inside the section and connected to a thermostat, a heat carrier in the form of a hardened sand-cement mixture with the ratio of sand from 65% to 70%, cement from 30% to 35%. At the same time, at least a triple layer of glass fibre mesh with a mesh size of not more than 4 mm is located between the heating element and the body sheets. The distance from the heating element to the metal sheets is 5 to 10 mm. The heating element is connected to a voltage source by terminals and an electric wire, the contact of the heating element and/or power supply wire with the housing is excluded due to the ceramic bushing rigidly installed in the housing.

EFFECT: creation of an electric heater section that provides reliable electrical protection, fire safety, with increased heat transfer while saving electricity

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Description

Field of technology

The invention relates to the field of thermal power engineering, namely to sectional heaters and heating systems using electric heaters. The inventive solution can be used for both primary and additional heating of residential, public and industrial premises - when designing electric heating devices with a rated power not exceeding 3 kW.

State of the art

Various solutions are known from the prior art aimed at heating and heating various domestic or industrial premises.

There are devices and methods that use heating systems using a coolant to heat the latter, for example, systems using solid fuel (Yu.L. Gusev. Fundamentals of designing boiler plants. M., Stroyizdat, 1973, pp. 239-241) or gas RF patent No. 2452906, No. 2652974 boilers; the disadvantages of such systems are the bulkiness of the design and the need to use pipelines.

Various electric heating devices are known, for example: according to RF patent No. 2124819, which describes a device containing heating sections vertically installed in a protective casing with a gap between them and consisting of a frame with an electrical insulating material applied to it. A heating tape is wound on top of the latter with gaps between the turns, electrically connected to the electrical network. Under the heating sections there is a lower reflective screen mounted on a protective casing with the ability to regulate the distance between it and the heating sections. Between the heating sections and the protective casing, a side reflective screen is installed vertically along its perimeter;

heating device according to RF patent No. 2217664, consisting of rectangular or square panels of metal, preferably aluminum, each of which is equipped with an insulating panel on the back side containing an electric heating cable laid in zigzag sections under the heated surface. The assembled panels are laid on the base close to each other in a consistent position;

heating device according to RF patent No. 2318165, containing a plurality of heating panels installed in the housing at the same distance from each other. The body has many openings. Each heating panel contains a heating layer, which is sandwiched between two insulating plates, two wires connected to the heating layer. Each wire has second connectors for connecting to first power bus connectors of a power control device connected to the housing;

electric heating panel of a heating system, according to RF patent No. 44025, containing a housing, a plug connector and a socket connector, between which is connected a heating element containing an insulated heating cable fixed to the housing by means of insulators, and a panel casing, while the plug connector is equipped with contacts for connections to the power supply network, and the socket connector has contacts for connection to subsequent panels of the system, the connectors are electrically connected to each other and equipped with busbars for grounding, the heating element additionally contains a second insulated heating cable, the connectors are equipped with contacts for parallel connection of the heating element cables.

Electric heating devices use various fillers - coolants that accumulate and transfer heat to the body of the device, for example: liquid (water, oil), bulk or solid coolants. In addition, various solutions are used regarding heater housings, this also applies to the shape of products and materials for manufacturing the housings. The most popular options are metal heater bodies, but recently there has been a growing popularity of ceramic heating elements, for example, made from a mixture of quartz sand and marble chips, bonded with cement mortar. There are also ceramic heaters, among which there are those in which the solid coolant is both the filler and the body devices, for example, the solution according to RF patent No. 152820.

Also known:

electric heater RF patent No. 2074522, containing a monolithic rectangular body made of insulating material based on sand and cement, in which two heating elements are embedded, connected to each other in series and having sections of at least two. The disadvantages of this device are the complexity of assembly and maintainability, as well as the need to insulate the heating elements when embedding them in the sand-cement mixture;

household electric heating device RF Patent No. 32951, in which the body is made in the form of a T-section frame with a side surface of ready-made ceramic tiles, a spiral heating element is attached to the frame by means of brackets, and the cavity is filled with a sand-cement mixture. The device has a fairly simple design, however, installing ready-made ceramic tiles on the surface of the heater does not ensure reliable fastening due to the temperature difference in the middle of the flat surface and along its edges.

The closest analogue of the claimed device is an electric heater patent of the Russian Federation No. 106479, containing a monolithic rectangular body made of insulating concrete material based on quartz sand and cement, into which a heating element with a number of sections of at least two is embedded, equidistant from the heated surfaces and made in the form of a zigzag, while sand, quartz sand cleared of organic impurities is used, and the heating element is made in two tiers and is embedded without gaps in the sand-cement mixture, which, after hardening, serves as a body, on the end part of which there is an edging made of an aluminum T-profile in the form of a frame with a sleeve installed in it at the location of the leads of the supply wire, two of which are connected to the ends of the heating element inside the frame, and the third is connected to the frame from the inside.

The disadvantages of the known solutions are the complexity, cost of the design and high consumption of energy resources.

Disclosure of the Invention

The technical problem to be solved by the claimed invention is the production of a simple in design, economical room heating device.

The technical result of the claimed invention is to create an electric heater section that provides reliable electrical protection, fire safety, with increased heat transfer while saving electricity.

To achieve the specified technical result, an electric heater section is proposed, consisting of a housing, which is a box in the form of a rectangular frame made of aluminum profiles, the bases of which cover the end sides of the section, and the sides of which are rigidly fastened to corrugated sheets with a thickness of 0.8 to 1.2 mm, heating element, made of low-carbon steel wire with a diameter of 0.8 to 1.5 mm, wound in a spiral with a pitch of 2 to 3 mm, evenly located in coils inside the box over the entire section area with a distance between adjacent coils from 10 to 40 mm, a temperature sensor located inside the section and connected with a thermostat, coolant in the form of a hardened sand-cement mixture with a ratio of sand from 65% to 70%, cement from 30% to 35%, with at least a triple layer of fiberglass mesh with a cell no more than 4 mm located between the heating element and the sheets of the box, the distance from the heating element to the box sheets is from 4 to 10 mm, the distance from the heating element to the box profiles is at least 10 mm, the heating element is connected with stamps to the power supply wire brought out through a ceramic sleeve rigidly installed in the box profile.

A method for manufacturing an electric heater section is also proposed, which consists in manufacturing the section body by rigidly attaching one of the corrugated sheets to a rectangular frame made of aluminum profile to form a box, laying at least a triple layer of fiberglass mesh with a mesh size of no more than 4 mm on the inside of the corrugated sheet in the box , in pouring a solution of sand-cement mixture on top of a laid fiberglass mesh to a depth of 3 to 5 mm, laying a heating element made of low-carbon steel wire with a diameter of 0.8 to 1.5 mm, twisted, on top of the solution in turns over the entire area of the section with a distance of adjacent turns from 10 to 40 mm spiral with a pitch of 2 to 3 mm, placing a temperature sensor inside the section and connecting it to a thermostat, insulating the ends of the heating element and terminal connection to the electrical wire, installing a ceramic sleeve in the profile of the box for the electrical wire outlet, filling the internal cavity of the box with a solution of sand-cement mixture with subsequent drying under natural conditions until there is no electrical contact between the heating element and the body, while the sand-cement mixture has a ratio of sand from 65% to 70%, cement from 30% to 35%, and by rigidly attaching the second sheet of corrugated sheet to the box.

In the preferred embodiment, the corrugated sheets in the body are arranged so that the stiffeners are parallel to the long sides of the section.

The combination of the above essential features leads to the fact that:

The assembly speed of the heater section is significantly increased;

The efficiency of electricity increases significantly with high heat transfer due to the use of a heating element made of low-carbon steel;

The simplicity of the design and the materials used simplify maintainability with significant savings in production and repair costs.

Brief description of drawings

In fig. 1 shows a top view of the proposed section of the device, where the number indicates:

1 - Profile, frame

In fig. Figure 2 shows a side view of the proposed section of the device, where the number indicates:

2 - Body made of corrugated sheets

In fig. Figure 3 shows a cross-sectional diagram of the proposed device, where the numbers indicate:

1 - Profile, frame;

2 - Body made of corrugated sheets

3 - Fiberglass mesh

4 - Heating spiral

5 - Filler, heater coolant

6 - Fastening

In fig. Figure 4 shows a diagram of a heating system consisting of 6 sections of electric heaters (C1-C6)

Implementation and examples of implementation of the invention

The proposed solution can be represented by a heating system that includes at least one electric heater section.

The electric heater section according to figures 1-3 consists of a housing 2 made of metal sheets, preferably profiled with a thickness of 0.8 to 1.2 mm, fixed to aluminum profiles 1 by means of rivets, self-tapping screws, bolts, etc. while the end sides of the device are closed with bases profile 1 on the sides, to which side sheets 2 are attached, hardened sand-cement mixture 5 can be used as a coolant filler, both with and without various additives. The ratios in the mixture are sand from 65% to 70%, cement from 30% to 35%. Use ordinary sand of fraction 0.5-1 or quartz sand of a similar fraction.

Between the sheets 2 of the body and the coolant 5 there is at least a triple layer of fiberglass mesh 3 with a cell size of no more than 4 mm. Heating spiral 4 is a low-carbon steel wire (optimal option St3) with a diameter of 0.8 to 1.5 mm, wound in a spiral with a pitch of 2 to 3 mm.

The optimal pitch of wire turns is from 10 to 40 mm. The distance from the heating element (spiral) 4 to the metal sheets 2 of the housing can be from 4 to 10 mm. The distance from the heating element 4 to the housing profiles 1 must be at least 10 mm.

The heating element is connected by means of stamps (not shown in the drawings) to the power supply wire, which is led out through profile 1, while contact between the power supply wire or heating element and profile 1 is eliminated due to the use of a ceramic bushing (not shown in the drawings) rigidly installed in the profile.

The section is equipped with a thermostat (not shown in the drawings) rigidly mounted on housing 2 or profile 1 with the ability to regulate temperature over 90 degrees, both with and without Wi-Fi function, connected to a temperature sensor located inside the section; options for installing the thermostat separately from the housing are possible devices.

The section may contain a built-in mount or wall mounts rigidly installed on professional sheets. flooring 2 as close as possible (no more than 20 mm) to the location of profile 1.

When using a heating system consisting of several sections, the latter are connected in series or mixed (parallel-series) Fig. 4 in this case, you can use one thermostat installed either on one of the sections or separately from them.

For heating residential premises, a set of an even number of flat panels-sections with dimensions of 600×900×36 mm, heated by electric current from the household electrical network, is used.

The number of sections in a set can be 6, 8 or 10 pieces, depending on the area or volume of the room.

One section is designed to heat a room with an area of 8 m2 or 20 m3 of volume.

The total resistance of the sections in the sets should be 90 Ohms. The resistance of the sections in the set must be equal. The discrepancy is allowed no more than 0.2 Ohm.

The method for manufacturing the heater section consists of:

- Manufacturing of casings from prof. Flooring fixed to the profile;

- Preparation of a heating element-spiral made of low-carbon steel wire;

Placements inside the manufactured box, for each sheet of prof. flooring with at least a triple layer of fiberglass mesh (plaster mesh with a mesh size of no more than 4 mm);

- Placement of the manufactured heating coil and temperature sensor;

- Insulating the heating element leads from the profile and connecting the power cable to them;

- Filling with mortar;

- Drying sections;

- Section assemblies - fastening the second sheet of prof. Flooring.

Dimensions and modifications

An electric, stationary heating system (hereinafter referred to as ESSO) is a set of “flat” panels measuring 600×900×36 mm sections (“batteries”), which are mounted on the walls in a living space and serve to heat the home throughout the entire heating season. .

The sections are attached to the walls of the room with a gap between the section and the wall of at least 20 mm. This is necessary for better air convection during section operation. The section is heated by electric current from a household network (220 V; 50 Hz). The optimal room area or volume that one section effectively provides with heat, meeting accepted ergonomic requirements, is 8 ^m2 of area or 20 ^m2 of room volume. At the heating temperature of each section (+50°C), a set consisting of an even number of sections (in a house or apartment) completely heats the home during the heating season.

The section is a metal box measuring 600×900×36 mm, inside of which a spiral of low-carbon steel wire is laid. The spiral in the box is filled with filler, which, after drying, protects from mechanical damage, moisture ingress, and also provides, due to its inertness, smoother heating - cooling - heating, in comparison with heaters with an open spiral. The filling of the spiral provides reliable electrical protection and fire safety.

The sections in the kit are connected in series; to avoid possible electrical injuries, each section is grounded. The section heating temperature is adjusted by a thermostat kit built into one of the sections, operating in the “on-off” mode. This mode, along with the optimal set resistance of 90 Ohms, allows for stable and economical operation of the ESSO. Taking into account the houses and apartments already in the housing stock, three types of sets are offered: from 6, 8 and 10 sections. The even number was chosen based on the application, along with the serial connection of sections, which gives moderate and economical operation of the system, the so-called “increased” mode, in which the connection of sections is mixed, i.e. parallel-series: the number of sections is divided into 2 groups of sections with the same number of sections in the group. This mode can be used as an auxiliary mode to quickly warm up sections. When the section is heated to +50°C, it is recommended to switch the system to a moderate system operating mode, i.e. on (mode) when the sections in the room are connected in series. The transition from one mode to another is carried out by a switch.

From a number of practically manufactured kits, the material and diameter of the wire used in the design of the heating element were selected. This is an ordinary low-carbon steel wire with a diameter of 1.2 mm, or as it is also called - knitting wire. The sections of the kit are connected with copper or aluminum wires, which can be hidden in the walls or laid along the baseboards of the room.

Example

Production of the heater section

We manufacture the section body from industrially produced corrugated sheet S-80 and profile P-28. We put a sheet of corrugated sheet (598×898 mm in size) into a rectangular frame made of P-28 profile (600×900×28 in size) according to the section drawing (sectional view). We rigidly fasten the corrugated sheet with the frame with rivets or use spot welding. Moreover, when laying the corrugated sheet in the frame, we place it so that its stiffeners are along the length of the frame.

Inside the manufactured box - on a sheet of corrugated board - we lay a triple layer of fiberglass mesh (plaster mesh with a mesh size of no more than 4 mm). This mesh acts as an insulator of the spiral from the body. In order to ensure the solidity of the coolant (to avoid the formation of voids and better adhesion to the mesh), as well as to maintain the minimum distance from the heating element to the body sheet, the mixture is poured over the laid mesh to a depth of at least 3-5 mm, or dielectric plates are laid on which In the future, a heating element will be installed to maintain a gap between it and the body. The manufactured spiral is placed on a grid, or dielectric plates, or a layer of solution. The placement of the spiral must be uniform in the cavity of the box to prevent contact of the spiral turns with each other. The ends of the spiral must have terminals isolated from the body to which voltage will be applied. We fill the laid spiral into the box with a solution (ordinary construction cement-sand mortar in a ratio of 1: 3 is allowed), one of the main properties of the poured solution is that after drying and hardening it should not crack at a heating temperature of 100÷120°C. This can also be achieved with the specified solution by using commercially available chemical additives.

An important stage in the manufacture of ESSO is the sum of the sections. The sum of the sections is the resistance of the set equal to 90 Ohms, i.e. for a set of 6 sections - 90 Ohm, for a set of 8 sections - 90 Ohm, for a set of 10 sections also 90 Ohm. Let's determine the length of the wire going to the set. Let's use the well-known formula:

where R is the resistance of the set in Ohms.

- resistivity of the wire (in our case for St 3 - )

l - wire length in m;

S - cross-section of the wire (1 mm ² ).

Then:

For the proposed kits, the wire length will be 450 m. The resistances of the sections in the kit must be equal. We indicate the wire lengths for the sections in the proposed kits in the table below.

Making spirals for sections is not particularly difficult.

The following sequence is used to produce ESSO:

Making a spiral from low-carbon steel wire with a diameter of 1.2 mm. Manufacturing of the section body.

Laying and subsequent filling of the spiral in the section body.

Drying.

Installation on one of the sections of the thermostat kit.

Placing the sections of the kit in a heated room and attaching them to the walls, as well as their connection according to the electrical diagram.

Connecting the kit to a household power supply

Manufacturing the section and subsequently the heating system includes the following steps:

To make a heating element-spiral, we take low-carbon steel wire (St3) with a diameter of 1.2 mm. The amount of wire required for the manufacture of the ESSO kit is determined by simple physical and mathematical calculations.

Considering that it is more profitable for ESSO, we manufacture the section body from industrially produced corrugated sheets S-80 and profile P-28. We put a sheet of corrugated board (size 598×898 mm) into a rectangular frame made of profile P-28 (size 600×900×28), according to the section drawing (sectional view). We rigidly fasten the corrugated sheet with the frame with rivets or use spot welding. Moreover, when laying the corrugated sheet in the frame, we place it so that its stiffeners are along the length of the frame.

Inside the manufactured box, on a sheet of corrugated board, we lay a triple layer of fiberglass mesh (plaster mesh with a mesh size of no more than 4 mm). This mesh acts as an insulator of the spiral from the body. We lay the manufactured spiral on the mesh. The placement of the spiral must be uniform in the cavity of the box, excluding contacts of the spiral turns with each other.

The ends of the spiral must be insulated from the body, the terminals to which voltage will be supplied. Fill the laid spiral into the box with mortar (ordinary construction cement-sand mortar in a ratio of 1:3 is allowed). One of the main properties of the poured solution is that after drying and hardening it should not crack at a heating temperature of 100-120°C. This can be achieved with the specified solution by using chemical additives or using Cement marked M 300 or higher for the mixture. An important stage in the production of ESSO is the drying of the sections. The sections are dried under conditions usual for drying and hardening cement-sand mortars (optimal temperature from 15 to 35 degrees, humidity above 60%). The section is considered dry if there is no electrical contact between the coil and the body. This can be checked with a regular ohmmeter.

We install a thermostat on one of the sections of the kit. Methods for installing a thermostat can be different - it all depends on the design of the thermostats. The part of the section that is not covered with metal must be closed. We will make the covering sheet from the already known sheet of corrugated steel S-80 (size 600×900 mm), the stiffening ribs of which will be arranged along the width of the section. This sheet will be the front or front sheet. The combination of the arrangement of the stiffeners of the front sheet along the width of the section, and the rear or wall ones along the length of the section, gives it additional durable properties. We attach the covering sheet to the box with rivets, the section is ready for work.

We place the sections of the kit indoors, securing them to the walls. When attaching the section to the walls, we maintain a gap of at least 20 mm (between the section and the wall), as necessary conditions for ensuring convection. We connect the sections according to the electrical diagram using copper or aluminum wires.

After completing the installation, we connect the ESSO to the electrical network. The connection can be different from a regular outlet to various types of switches designed for a current of 6A.

Thus, in the proposed invention it was possible to develop an economical section of the electric heater, the production of which does not require special costs and materials, which makes it possible to efficiently and quickly carry out assembly and repair.

Claims (3)

1. Electric heater section, consisting of a body, which is a box in the form of a rectangular frame made of aluminum profiles, the bases of which cover the end sides of the section and the sides of which are rigidly fastened to corrugated sheets with a thickness of 0.8 to 1.2 mm, a heating element made of low-carbon steel wire with a diameter of 0.8 to 1.5 mm, wound in a spiral with a pitch of 2 to 3 mm, evenly spaced in turns inside the box over the entire area of the section with a distance between adjacent turns from 10 to 40 mm, a temperature sensor located inside the section and connected to a thermostat, coolant in the form of a hardened sand-cement mixture with a ratio of sand from 65% to 70%, cement from 30% to 35%, with at least a triple layer of fiberglass mesh with a cell no more than 4 mm located between the heating element and the sheets of the box, the distance from the heating element element to the box sheets is from 4 to 10 mm, the distance from the heating element to the box profiles is at least 10 mm, the heating element is connected by terminals to the power supply wire brought out through a ceramic sleeve rigidly installed in the box profile. 2. The method of manufacturing an electric heater section according to claim 1, which consists in manufacturing the section body by rigidly attaching one of the corrugated sheets to a rectangular frame made of aluminum profile to form a box, laying at least a triple layer of fiberglass mesh with a mesh size of no more than 4 mm on the inner side sheet of corrugated sheets in a box, pouring a sand-cement mixture solution on top of a laid fiberglass mesh to a depth of 3 to 5 mm, laying a heating element made of low-carbon steel wire with a diameter of 0.8 on top of the solution in turns over the entire area of the section with a distance between adjacent turns from 10 to 40 mm up to 1.5 mm, wound in a spiral with a pitch of 2 to 3 mm, placing the temperature sensor inside the section and connecting it to the thermostat, insulating the ends of the heating element and terminal connection to the electrical wire, installing a ceramic sleeve in the profile of the box for the electrical wire output, filling the internal cavity boxes with a solution of sand-cement mixture, followed by drying under natural conditions until there is no electrical contact between the heating element and the body, while the sand-cement mixture has a ratio of sand from 65% to 70%, cement from 30% to 35%, and in and rigidly attaching the second sheet of corrugated sheet to box. 3. The device according to claim 1, characterized in that the corrugated sheets in the body are arranged so that the stiffeners are parallel to the long sides of the section.

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