Muffle furnace DIY repair

Message # 1 sergey1960 »13 May 2016, 20:04

Message # 2 VVKV »13 May 2016, 20:47

4000 r.), The wire for the heater too, the heat-insulating backfill is also not a problem (it will have to be added, it either caked or partially spilled out), the temperature regulator can also be bought. The outside coating for the muffle is also commercially available. The repair technology is well covered on the well-known forum, and certainly not only there. The only problem with which there may be a problem is with the heat-insulating pad on the door (its state is not visible in the photo, it is possible that it is split and part of the debris is lost). I have never seen it on sale. And the body can be badly dented (also not visible in the photo). As for the feasibility of restoration, the new PM-8 from storage costs 10.12 thousand rubles. The only thing that needs to be done with it before putting it into operation is to fill up the backfill, it cakes over time. And a modern electronic temperature controller will not be superfluous, although you can do without it using a standard system with a switch and resistors.
And if you undertake to restore, be careful - the edges of the body parts made of steel sheet are very sharp: one careless movement, and a deep, long-lasting cut is guaranteed.

The muffle furnace is designed for heating and firing all kinds of materials. A special feature is the presence of a muffle - the main element of the furnace, it allows you to protect the fired material from combustion products and fuel, work with clean material, and ensure a uniform temperature field. This is the working surface of the oven. It is made from ceramics, ceramic or special fibers.

Serves as a muffle furnace for:

1. Smelting and burning wax out of molds;
2. Firing of casting molds;
3. Firing ceramics;
4. Melting and brazing of metals;
5. High temperature processing of materials.

Muffle furnaces are divided according to the following characteristics:

• Temperature (muffle furnaces of moderate temperature - 100-500 degrees Celsius, medium - 400-900 о С, high - 400-1400 о С, ultra-high - 400-1700 о С);
• Processing mode protection;
• Design;
• Heat.

In practice, kilns for firing ceramics are widely used; in laboratories, such kilns are used to study the properties of materials.

The main feature of such a furnace, of course, is the muffle itself, we have already talked about it. Also distinguishes these ovens and the location of the heating element. Depending on the type of furnace, the heating elements are located either on the muffle or inside it. This allows for uniform heating of parts and products.

The muffle box insulates the firing parts from hot gases and vapors. They go around it and envelop the furnace and the working surface, thereby transferring heat to the walls of the muffle, which spends it on heating and firing the workpieces. This allows you to avoid scale on the products, which makes it possible not to spoil their appearance, especially of ceramic products.

A muffle furnace removes harmful substances that are released during firing and heating of materials by means of ventilation in the structure.

Good ovens have a temperature controller. The simplest form is an indicator of the current temperature. In more complex and high-quality models, you can find an indicator of the current, set temperature, allows you to set the heating rate and exposure duration. Expensive models have 30 heating modes.

It is not difficult to buy a muffle furnace, many well-known manufacturers offer this product.The price for muffle furnaces depends on the volume, the complexity of the technical component, the presence of additional elements (hood, grates, etc.).

The price for muffle furnaces in Russia ranges from 30,000 to 140,000 rubles. The average price for fume hoods for a muffle furnace is 30,000 - 37,000 rubles.

Video review of the muffle furnace

Most often, in this kind of ovens, problems arise with wires. In the process of firing, the nichrome wire can burn out.

Simple calculations of the length of the wire for replacement - and the breakdown is eliminated. 5 meters is enough for a 300 W heater, depending on the section, the length will change. Price per kg. in a huge coil of nichrome is 1150 rubles, we need much less to repair the furnace.

Less often, but it also occurs that the heater burns out. To make repairs, you will need refractory clay, powder chamotte and asbestos. Most of the materials can be found in the boiler room. The muffle is removed from the furnace, a tester is taken and the place of breakage, burnout is found.

We release the spiral from the coating by 1.5 centimeters at the edges. We will need nichrome again, we will carefully screw it to the edges of the spiral, bent 90 degrees to the body. We lay new areas in place of the burnt ones and connect the second end of the cliff.

We restore the coating - we smear the twisting places with brown and sealed with a carbon electrode. The entire repair site is coated with a mixture of chamotte and refractory clay. If you wish, such repairs may not cost you a dime.

To repair a ceramic muffle, a mixture of talc and water glass is required. You can use silicate glue with refractory brick shards, but this method is less reliable. In general, the repair of the muffle itself is not very necessary, the furnace works properly with small cracks.

It is not difficult to use a muffle furnace, but each device has its own nuances. When baking ceramics, an unsatisfactory result will be especially noticeable - the color is not the same, cracks, etc. First of all, you need to monitor the cleanliness of the muffle chamber, there is less carbon deposits than in a conventional furnace, but there are various damages.

During operation, thermal settings can be knocked down, they should also be paid attention to from time to time.

The oven should be located on a level surface, preferably free from vibration. Do not drop or hit the oven body.

Also, ovens do not like dusty and humid rooms.

Repair of muffle furnaces may be necessary due to wear of components or improper operation of equipment. To avoid serious breakdowns and poor-quality firing of materials, it is necessary to repair damaged areas in a timely manner.

Regardless of the model, muffle furnaces have similar problems.

After repeated firing of raw materials, the nichrome cable may be damaged. Most often, a breakdown is corrected by simply replacing it. To do this, it is necessary to correctly calculate the length of the wire, which can vary depending on the cross-section.

Such repair of muffle furnaces in St. Petersburg is quite inexpensive due to the low price of consumables.

The muffle is a chamber in the furnace, necessary to protect the processed materials from the effects of combustion products and the influence of the heating element.

Repair and manufacture of muffle furnaces in St. Petersburg is carried out using heat-resistant materials. Several components are needed to restore the heater:

• Powdered chamotte.
• Fire-clay.
• Asbestos.

To find the breakage point, the muffle is removed from the housing. A special tester allows you to identify the problem area in a matter of minutes. Thereafter:

• The spiral is cleared from the coating.
• Nichrome is attached to the edges of the heating element.
• New zones are being laid to replace the burned ones.
• The edges of the cliff are connected.

Electric furnaces with a ceramic chamber are equipped with a heating element protection system. The components are recessed into special grooves. After a well-carried out repair, the devices work no worse than new ones.

To repair a ceramic muffle, you will need a composition of liquid glass and talc. Silicate glue is also used with the addition of refractory brick chips.

It is worth noting that the oven fulfills its function even in the presence of minor cracks.

To restore the coating of the stranding area, refractory clay and chamotte are used. For reliability, soldering is performed with a carbon electrode

The SNOL muffle furnace, which should be repaired by specialists, will serve you for a long time and without interruption, subject to:

• The purity of the muffle chamber.
• Thermal settings.
• Smooth location of the oven.

To prevent damage to the device, do not allow dust or high humidity in the room. Also, you should avoid hitting the oven body and dropping equipment.

When you contact Labor, you can choose muffle or shaft furnaces and other specialized equipment. Call us, we will answer all your questions!

The muffle kiln is an essential piece of equipment in jewelry or ceramic workshops. This device allows you to create the necessary temperature conditions for heating and melting metal, firing ceramics or joining enamels with glass. A muffle furnace is also used in the manufacture of tiles, in the hardening of these products and in strengthening the enamel layer. There are many other options for using such equipment.

DIY muffle furnace

Factory-made devices are quite expensive. But it is quite possible to make such equipment with the characteristics necessary for work and independently. A do-it-yourself muffle furnace is often assembled by craftsmen who are engaged in one of the above types of work.

And in order for the device to function effectively, it is necessary not only to choose the right material and make the high-temperature chamber itself, but also to correctly calculate the operating parameters of the electrical part, purchase the required components and make a competent installation.

All this will be discussed in this publication.

There is a fairly wide variety of types of muffle furnaces, which are subdivided according to a number of criteria - according to the source of energy and power used for heating, according to linear parameters and the location of the working chamber, and other characteristics.

One of the many examples of a self-made muffle furnace

• By the nature of the energy source used for heating, such furnaces can be divided into three options - solid fuel (usually coal), gas and electric.

- Of course, in our time, electric muffle furnaces are considered the most efficient models. Their convenience lies in the ability to achieve the required high temperature in the shortest possible time, as well as in relative safety with correct assembly and compliance with all operating requirements. When using electric ovens, it is possible to very accurately set and control the heating temperature in the working chamber. Such devices are compact and can be used to work even in a small workshop (or even in an apartment) from a mains voltage of 220 volts, if, of course, the power of the power line allows. The socket through which it is planned to connect the device to the network must be grounded without fail. In fact, there are no other requirements, so the installation of such an electric furnace will not require any administrative procedures, such as obtaining the appropriate operating permits.

- It is strongly not recommended to assemble a gas-powered device in artisanal conditions. The fact is that homemade gas appliances are strictly prohibited for use due to their increased danger, and very serious problems with regulatory organizations can arise.

- The furnace, heated from the combustion of coal, is not efficient enough, since it takes a long time to enter the operating mode, it needs a separate room, and additional troubles will arise associated with the delivery of solid fuel and the organization of its proper storage. True, in fairness, it should be noted that coal muffle furnaces take a long time to heat up, but on the other hand, they maintain the reached temperature for longer. And in terms of economic operation, they also benefit in comparison with electrical appliances.

But the advantages of an electric muffle furnace still far outweigh its only significant drawback - the high cost of electricity. Therefore, in the future, the conversation will focus only on this option.

• Depending on the purpose of the muffle furnace, it can have a vertical or horizontal position of the furnace. In addition, devices can be subdivided into tubular, bell-type, and other specific shapes.

Ovens with a horizontally positioned chamber are easier to manufacture and convenient to operate. They have sufficient functionality, for example, they can melt many metals, burn ceramics, and temper steel products.

Immediately you need to decide what a muffle is, so that in the future there are no questions about the name of the device. So, this term is understood as a closed chamber in which the temperature necessary for a particular technological process is created, but at the same time contact of the processed material with the fuel itself or with the products of its combustion is excluded. In the case of electricity, combustion products can no longer be simple by definition, but nevertheless the name "muffle furnace" stuck - they are due to the similarity of technological operations performed with the help of such equipment.

The muffle furnace can be of different designs. When creating its electrical version, certain heating elements are used, depending on what temperature should be reached in the working chamber. As a rule, the temperature range lies in the range from 200 to 1000 ÷ 1100 degrees - this is enough for high-quality firing of ceramics, melting or hardening of many metals. But in some cases it is necessary to reach heating up to 1300 ÷ 1500 degrees - however, such furnaces are already usually used in production or laboratory conditions.

An example of a common muffle furnace design.

• The heating chamber is made of fireclay refractory bricks or SHPGT-450 plates, resistant to extremely high temperatures and chemically neutral to alkalis or acids. Plates are more convenient to use, as they have rather large linear dimensions. Therefore, unlike bricks, one wall of the chamber can be immediately made from one slab. In addition, they have the optimal thickness, composition and structural structure for such operating conditions, which allows you to quickly pump and maintain the required temperature inside the furnace.
• To reduce heat loss from the outside, the muffle chamber is wrapped in heat-insulating heat-resistant material. Most often, for this purpose, basalt-based mineral wool is used, as the most resistant to sintering. By reducing heat loss, the efficiency of the device increases - the furnace heats up much faster, holds high temperatures longer and consumes less energy from an external source.

If fireclay brick is used to form the chamber, then the heat-insulating layer becomes thicker. This is understandable - the slabs have higher thermal insulation characteristics and have fewer butt joints, which are also often the cause of heat loss.

Previously, asbestos was widely used to insulate the muffle chamber.Today, it is practically not used for two reasons - when heated, it emits a fairly significant amount of harmful substances, and, heating up to a temperature of 1000 degrees or more, it loses its internal connections, gradually turning into crumbs.

• A spiral is most often used as a heating element installed inside the chamber. When self-assembling, the furnace and the spiral are usually made on their own from a special wire, the characteristics of which will be discussed below.
• For the muffle chamber, a metal frame is made by welding from a steel angle, which, after installing the insulated muffle chamber into it, is sheathed with a metal sheet 1.5 ÷ 2 mm thick.
• The chamber door must be of the same thickness as the walls, and additionally equipped with a layer of thermal insulation, for example, of the same mineral wool. In addition, a reliable lock is installed on the door, which will firmly press it against the front of the heating chamber. As a lock, latches, twists, attracting hooks and other similar devices are used.

The doors are mounted on hinged hinges, which are fixed to the frame by welding. The door can be hinged, hinged, or even removable, if, for example, it is intended to make an oven that opens from above. The latter option is more likely to be called a lid than a door. It is quite convenient in operation, but you can hardly call it practical - when you remove the cover, the chamber immediately opens along its entire length, which contributes to the rapid and massive leakage of the generated heat.

• For the electric version of the muffle furnace, one of its most important units is the device control system, which includes a lot of elements. It has a rather complex structure, which is assembled according to the calculations carried out according to a pre-drawn scheme. However, there is no shortage of ready-made solutions to this problem.

Due to the fact that this part of the structure can be called the most complex, a separate section of the article should be devoted to its calculations and assembly.

To carry out such calculations, some initial data will be required. These include the dimensions of the device being created and its estimated power, the material of manufacture of the heater, the level of required temperatures in the muffle chamber, the placement and design features of the heating elements. The result of the calculations will be the diameter of the wire used for the heating element and its required length.

Heaters for a muffle electric furnace are most often made spiral - wound from wire with high resistance and heat resistance.

The power of the furnace directly depends on the size of the muffle chamber and the material used for its manufacture. The volume of the chamber is determined independently, depending on the parameters of the products that will be placed in it for processing.

Due to the fact that the walls of the muffle are most often made of fireclay bricks or from plates ШПВ-350, which have high thermal insulation qualities, and materials such as mullite-silica felt (MKRV) or mineral wool on a basalt basis are used as an additional heat insulator. some empirical recommendations (that is, grounded experience in the practical application of such structures).

So, when determining the power of the future furnace, one can start from the dimensions of the muffle chamber (in liters) and the following empirical values ​​of the specific power (W / L):

Hello! I want to buy a muffle furnace for making small ceramic jewelry. I turned up used for 800 UAH (3200 rubles). The seller sent a photo. Please advise what is worth paying attention to, what is worth asking the seller so that you do not buy "firewood" at all. The oven is working properly. Brand PM-8. I plan to work with glazes.

It seems to me not necessary. You can't see the muffle inside, maybe it's just an oven?

And this could be? I looked at the brand - it should look a little differently

... Is it really not a bake? Or maybe just an old one?

Type PM-8 in the search engine and compare the photos.

What is being slipped at you is not clear at all! For firing ceramics (we are talking about a temperature of 1000 g), there can be no metal surfaces inside the furnace at all!

I also thought it was a drying cabinet.

Muffle furnace, the inside must not be rusty.
Inside, the space should be lined with a muffle, and not with rusted metal.

some kind of pepelats, thin-walled drying, there are no therma-pairs, the wiring is open,)) under the glaze and clay, a minimum of 850 degrees is needed, or better with a margin of a thousand

It's good that you asked. Colleagues correctly pointed out the real muffle furnace. Only the spirals there need to be checked if used to buy. Rewinding will be a pretty penny, and understand one thing - the oven eats electricity with appetite. That is why I don’t buy.

And in the “oven” that the villain offered you, let him dry his socks.

Thanks a lot! Yes, something is wrong with the oven. Thanks everyone for the help!

And I would also be extremely wary of the price: on the same Internet I have not seen such low prices, even very used ones.

Well, yes .. this is what is apparently left of the oven :)))) the oven of this brand is not suitable for working with glaze - tk. she has a maximum temperature of 900'C. And for glaze you need 1040 and above.

If you raskachegarete such a stove - it will burn out for you - I have a sad example of that.

I ordered a normal oven in Cherkassy.

Thank you, Vera! Which one did you order?

I ordered a 1200'C muffle furnace. It cost me about 4 thousand UAH.

I ordered a stove with open spirals. Moreover, the spirals on the bottom too. Now I would order a cylindrical one with spirals in a circle.

“Muffle is not visible”, “must be laid out of the muffle”

if you take a stove, it is strongly discouraged to take a "muffle" -type construction;

it is optimal to take a stove with open spirals - at least you can treat it, if that

such a stove with a view of the camera looks like an electric kettle - that is, the spiral is in sight, it can always be changed ..

a muffle is a construction with a closed spiral, and not a "ceramic stove", stoves have different designs, ideally the heaters should be visible and accessible for repair, this is certainly not a muffle .. for example, my stove is NOT a muffle for ceramics, and children in the studio also do not have “muffle” furnaces

I have such a feeling that people simply do not know other words besides “muffle” and do not want to know ..

and the camera is laid out with a thermal insulator, they are different there, and even the awful word “asbestos” appears - not, but of course, they are normally asbestos.

that in the photo, I’m even at a loss to say, the rust there is from bream, scale, it’s not iron in the chamber.

and that there should not be metal inside - yes, don't listen, the props are made of metal, but not from all of them.

and about temperatures - also a lot of crazy written .. glaze - yes, and from 900 there are glazes, there are just few of them and they are rotten at a minimum, and from 950 glazes are already just full

and if Th - sometimes they give quite a decent stove for nothing, then somehow they gave such a sweetheart to YAM - I already cried that I had nowhere to stick it ..

and that there is a stove of electricity eating up - yes, do not drive it with two jobs every day, score a full one and drive it out. for example, I have a power of about 5 kilowatts for 8-10 hours at 4.50 rubles per kilowatt - maybe we won't go broke for 200 rubles with a penny for firing once a week ..

Having a muffle furnace in your home workshop, you can already seriously master the heat treatment of metals, which is indispensable in the manufacture of knives, parts of mechanisms and tool technology. We offer a simple and inexpensive design for an automatic hardening furnace.

An electric hardening furnace can be easily built on the basis of a thin-walled container with a volume of 15 liters or more.For the most compact options, an ordinary galvanized bucket is suitable, for larger ones, you can use a washing machine tank, technical containers, or, for example, roll a sheet of roofing iron into a cylinder and fold the bottom with a single fold. The casing does not have to be non-combustible; it is enough for it to withstand temperatures of 80–100 ° C.

The body should be installed in such a way that the clearance from the surface is about 100 mm, for which you need to attach the simplest legs. As these, threaded rods bent with a bracket, the edges of which are inserted into the holes in the body and tightened with nuts on both sides, will fit. The height of the legs must be adjusted immediately and the nuts must be securely locked.

An electrical connection hole must be made in the back of the case. It is best to cut out a window with dimensions of 50x70 mm, and then install a fiberglass panel in this place with dimensions of about 100x120 mm. The connection of the heating elements is carried out on pins, while it is possible to bring out two or more pairs to organize several stages or work from a three-phase network.

The first stage in the manufacture of the hardening furnace itself will be the calculation and search for heating elements with their subsequent assembly into a single fuel loop. This can be done in two ways: by selecting ready-made heating coils or by making them yourself.

Choosing spirals is not very difficult, you just need to ensure that they are made of the correct material and have a sufficient cross section. For hardening furnaces, it is not recommended to use wire heating elements with a wire thickness of less than 0.4 mm. The optimal version of the spiral material is fechral X27Yu5T or Kh23Yu5-N-VI. The most important rule when working with such alloys is not to heat them until the final formation and assembly of the fuel loop.

The calculation of the heating elements must be carried out individually, taking into account the dimensions of the furnace and the corresponding heating power. As an example, you can take a furnace with a heating chamber dimensions of 150x100x300 mm. To heat such a space to a temperature of 1,100 ° C, a total power of the heating elements of about 4 kW will be required, but heating will be most economical when the total power of the coils is 5.5–6 kW. When connected to a 220 V network, the current will be 28 A, and the total resistance of the heater is 7.86 Ohm.

Using this data, we can easily find the required wire length with known electrical conductivity. The average resistivity of a fechral is 1.25 Ohm · mm 2 / m. If you use a wire with a diameter of 0.9 mm, its cross section will be 0.64 mm 2, which means that the resistance of one meter will be equal to 0.8 Ohm. Thus, it is required to create a heating element with a total wire length of 9.83 m. To twist the spiral, you need to use a mandrel rod, having previously calculated the length of one turn. If the coil has an outer diameter of 8 mm, the coil length will turn out to be slightly more than 25 mm, that is, the entire heating element will consist of 393 turns.

In a transverse section, the perimeter of the chamber is 500 mm, with a normal packing density in a firebox with a depth of 300 mm, the spiral is placed in 5 rows with an indent from the front edge of 40 mm. Thus, the total length of the spiral is 2.5 meters, the coiling must be evenly stretched to this length. If you roughly calculate, then after stretching the distance between the turns of the spiral will turn out to be a little more than 5 mm, which will ensure sufficient heating density. If the pitch turned out to be higher than 8 mm, the wire diameter would have to be reduced, and if the pitch of the turns was less than 3 mm, it would have to be increased.

The very concept of a muffle furnace implies the presence of a muffle - an internal heat-resistant capsule that closes the heating circuit spiral, protecting it from fine debris and scale. The muffle, as a rule, is removable in furnaces, which allows repair and replacement of heating elements.

The main difficulty is to manufacture the muffle and the heating assembly body at the same time. To do this, you need two types of heat-resistant ceramics: one for making a housing with grooves, the other for a thin-walled muffle. For a ceramic base, it is better to use a mixture of refractory clay with an alumina content of at least 30%. The clay should be diluted with excess water and left to swell for a day, then remove the settled water from above and leave only the swollen sediment.

The ceramic body of the heater is massive; therefore, it cannot be made of a pure binder; a filler is needed. As the latter, glass fiber, dry quartz sand or crushed chamotte are well suited. The total clay content in the solution should not be less than 50% by volume; as a result, the mixture acquires the consistency of a viscous plastic paste. If the composition turns out to be more liquid, the excess moisture is removed by adding small portions of stucco immediately before use.

Chamotte powder

The heater body is made on a volumetric template of corrugated cardboard, the dimensions of which should be 15–20 mm larger than the planned dimensions of the firebox on each side. First, a cord or a silicone hose of the appropriate diameter must be wound on the template, forming the required number of grooves for the spiral. After that, the template with a cord must be glued over with clay from all sides, avoiding the formation of voids and achieving a wall thickness of at least 40 mm. The addition of alabaster helps the piece to maintain its shape prior to firing. Carefully remove the cardboard insert from the dried ceramic body and pull the cord out of the grooves.

For the lining of the furnace, ceramics made of higher quality kaolin are used. Enriched clay of the KFN-2 brand is best suited; as a filler, it is better to use crushed high-purity chamotte with a content of about 20-25% by volume of dry components. The mixture is sealed in the manner described above and used to form the inner liner.

In order to easily separate the muffle, spirals are inserted into the ceramic body in advance. Then the inner surface is pasted over with shreds of newsprint according to the papier-mâché principle. You should get at least 8-10 layers, while the inner surface should contain as little roughness as possible. After the paper has dried, a refractory lining compound is applied from the inside. It is better to do this in several passes, allowing time for excess moisture to evaporate; as a result, the wall of the muffle should reach a thickness of 15–20 mm. In this state, the entire assembly is dried for several days until the complete loss of plasticity and the appearance of a sonorous sound when tapped.

After drying, the primary firing is performed - voltage is applied to the spirals and the hot product is kept for 4–6 hours. During the firing process, fechral passes the crystallization threshold and, becoming more fragile, takes the form of channels. The clay in the ceramic insert and muffle is baked and vitrified, gaining resistance to cyclic temperature changes. Well, the paper and glue residues simply burn out, while forming a minimum technological gap for easy removal and installation of the muffle.

With this manufacturing method, some tricks can be used. For example, to form a ceramic body on a tapered template to facilitate removal of the muffle. It would also not be superfluous to lengthen the front of the assembly, where there are no heaters, or place a small spiral at the bottom of the chamber. Themselves as muffles for one furnace, you can make several copies at once.

As a result of the described actions, an almost finished firebox of the hardening furnace is obtained, it only needs to be placed in the case, securely fastened and minimized heat loss. For this, a pre-made container with legs will come in handy.

The internal volume of the container must be filled with mineral wool with a density of 45-50 kg / m 3. The cotton wool needs to be rolled up in a spiral, first laying it under the outer walls and gradually moving towards the center. The packing density should be as high as possible, but at the same time the cotton wool itself cannot be damaged. As a result, the complete firebox must be placed in the central fold. If the density of the cotton wool is sufficient, the heating part will not crush the insulation with its weight. All spiral leads must be carefully wrapped with fiberglass, inserted between them spacers made of scraps of mineral wool, and then brought out through the back wall, connected to the back side of the studs and installed the panel in place.

To securely fix the firebox and install the door, the cotton wool must be crushed and sunk 6–8 cm deeper than the sides. The surface of the insulation must be sprinkled with alabaster milk several times so that the cotton wool hardens and stops intensively absorbing moisture. After that, the front part of the furnace is filled with a mixture of alabaster, sand and mineral fiber. While the composition is not frozen, a furnace door or mortgages for its fastening are embedded in it.

There are three types of hardening furnace automation. The cost of organizing the control of the oven increases along with the comfort of use. The simplest option is a simpler thermostat with a thermocouple as a temperature sensor. This device will simply maintain the set temperature with a hysteresis of about 30-50 ° C. The holding time is controlled manually, as well as the moment when the temperature point is reached.

More advanced automation is being developed specifically for electric ovens. Thermocontrollers of the Autonics TCN4 type have the function of proportional power control, providing an adjustable hysteresis up to 1 ° C. Also, the device is equipped with additional functions, such as an alarm that a preset temperature has been reached. If desired, the alarm channel can be used to activate a time delay relay in series with the thermostat.

The most advanced in this regard are the automation devices for furnaces of the "Profile-M" type. They differ not only in the built-in power relays, but also in the possibility of more flexible configuration. In such controllers, a timer is preset, and it is also possible to set up heat treatment with a complex temperature profile, sequentially setting the duration of time intervals in which a certain temperature should be maintained.