How to choose the right industrial convection oven for baking bread and other products

Converter lining

The most important goal of the design development strategy for converter linings is to achieve its high durability, ensuring converter operating efficiency that corresponds to the minimum unit costs for refractories. The last decade has been characterized by a radical increase in the durability of the converter lining through the use of a combined balanced scheme, taking into account the wear characteristics of individual zones, including those susceptible to increased erosion. Thus, in different zones of the converter lining, products of different quality and thickness are used, which ultimately leads to balanced wear of the lining as a whole (Table 4). The durability of the lining is increased by reducing the time of its direct contact with the oxygen stream. To do this, at the beginning of the blowing process, slag formation is forcibly accelerated by adding dolomitized lime to foam the slag. Of course, automation of the converter process also contributes to increasing the durability of the lining, reducing the number of converter scraps and preventing overheating of the steel at the end of melting. To increase the durability of the lining, the American companies Practer and Grate Lakes Division proposed a technology for blowing slag in an oxygen converter, which involves injecting high-pressure nitrogen through an upper oxygen or auxiliary lance to spray slag over the lining. At the same time, the slag covers the lining, cools and hardens, creating a strong protective crust that prevents wear of the refractories. The slag blowing technology involves rocking the converter to coat areas of the lining that are subject to increased wear during scrap dumping and metal draining. An additional positive effect from the slag skull is also achieved due to the fact that when cast iron is poured into the converter, the slag is partially melted, which leads to the creation of a certain layer of liquid slag even before the blowing begins. Modern methods of monitoring its condition with measurement play a significant role in increasing the durability of converter linings lining profile and degree of wear. An example of such equipment is a laser system for establishing the lining profile. A complete scan of the converter takes 25...30 minutes. Detected areas with low lining thickness are repaired with shotcrete and slag blowing. The lining is monitored 7…10 times during its operation. In general, today the normal durability of a converter lining is considered to be 2.5...3.5 thousand melts. Record figures based on system monitoring and additional lining repairs reach even 10...15 thousand melts or more.

Brick heating structures

The main advantage that stone stoves for summer cottages can boast of is their ability to retain heat for a long time. This is true when you have to stay in the building overnight on frosty days. However, it takes a long time to melt the structures, which is not very convenient for short-term use.

Relevance of application

Dimensions, efficiency, manufacturing complexity and other parameters were taken into account.

In first place is a Dutch oven for a summer house, as it has compact dimensions, which means it can be actively used in many rooms. Due to the presence of vertical channels, it has high thermal output.
The second position is occupied by the Swedish brick heating structure. It can fit in almost any building, of course, if these are not country houses made from block containers.
Third place goes to the Russian stove due to its impressive size and complexity of manufacture. This option is more suitable for residential buildings than for country houses.

Classification of structures

Depending on the purpose, heating, cooking and combined structures are distinguished. In the first case, only heating of the premises is carried out, in the second - only cooking. In addition, the structures can be combined directly with each other.

Ovens can be classified by the thickness of their walls, which can be thin or thick. The heating and cooling time depends on their size. For a country house, it is recommended to choose thin-walled structures, since they do not require a massive foundation.

Design possibilities

Using various types of finishing, the aesthetic characteristics of a brick structure can be formed. Unlike metal analogues, there are a great many options for improving external data.

If necessary, the cladding can be easily replaced, radically changing the perception of the heating structure.

Facing bricks can add a touch of modernity to the appearance, which is why they are very often used for finishing. Ideal for styles that feature predominantly straight lines.
Ceramic tiles, with their variety of colors and installation variations, can completely transform a design. Imitation of other materials, such as wood, looks interesting.
Decorative plaster provides the opportunity to create coatings with an aesthetically attractive texture. The result is exquisite products.
Handmade tiles allow you to create exclusive designs, which, after finishing work, act as the main source of attention.

Control

As a rule, modern mini-ovens come with mechanical controls - handles with which you can adjust the operating parameters. Depending on the model of switches, there may be several:

Temperature regulator.
Mode switch.
Time Timer.

Using the mode switch, you can select which heating element will participate in cooking. You can only turn on the upper heating element, only the lower one. There are “grill and convection”, “two heaters and spit” modes, etc. Some models have a defrost mode. Convection alone can also work - this will allow you to dry a portion of mushrooms, berries or herbs in a short time.

Metal products for heating

The basic advantage of such structures is the rapid transfer of heat to the surrounding air, although cooling also occurs in a short time. The decisive factor can be considered the low price, thanks to which the products successfully compete with brick analogues. During operation, there is a risk of getting burned if the housing has not been protected with other materials.

Basic classification methods

First of all, all products can be divided according to the material of manufacture. In modern markets, ordinary or heat-resistant steel is presented. The choice should primarily be based on operating conditions, since the characteristics of metals are completely different.

Another classification option takes into account the location of the product. Particularly popular are corner stoves for summer cottages, which do not take up much space and are therefore more suitable for small spaces. The choice in this case depends on the design decision.

The most important factor is the way the system is designed, which is explained by its particular impact on efficiency.

Chamber structures involve combustion of residual air through natural circulation. With this option, the afterburning chamber is combined with the firebox into a single module - the crucible.
Duct products imply the presence of special partitions between which flue gases pass, retaining heat. As a rule, the efficiency of the system does not exceed 60 percent.
Bell-type analogues are capable of trapping the initial combustion products under a kind of container until they release all their energy. Therefore, they are characterized by high efficiency.

Most popular representatives

Thanks to a competent design, air injection occurs without the use of additional devices. The temperature difference between the inlet and outlet flows leads to heat transfer in the gases. Convection ovens for summer cottages of this type allow you to achieve high efficiency.

Homemade systems

If necessary, a metal structure for heating can be made by hand. Of course, it is hardly worth pretending to create a creation that is distinguished by aesthetic qualities, but it is quite possible to build a neat structure, especially since when there is a shortage of budget, the main role is given to practicality.

At the initial stage of work, special attention is paid to the preparation of the elements necessary for assembly. As for tools, the list is not so long, because homemade stoves for a summer residence are made using a grinder and a welding machine

In a pipe with a diameter of at least 40 mm, two rectangular holes are first cut. One of them will be the firebox, and the other will be the ash pit. A hole for the chimney is created in the upper part. The grate is made from wire 6 mm thick.

Two circles are cut out of a steel sheet, the diameter of which will correspond to the width of the pipe. They are welded on the bottom and top sides, forming a sealed structure. At the last stage, doors are installed from the cut pieces using steel hinges.

Convection modes

In order to ensure an even and constant flow of heat energy from all sides of the oven, it uses forced convection.

The fan effectively creates uniform and continuous blowing of hot air over the food on the baking sheet. This prevents them from burning or not being baked. In addition, convection helps create a beautiful golden brown crust on pies and other products.

In simpler models of electric stoves, conventional fans of a simple design are installed, the task of which is to force the air to move inside the cabinet. In more complex units, the fan can be additionally equipped with a heating element, which is more efficient.

Ovens can be equipped with high-performance fans that quickly create a dense, even flow of hot air. This allows you to make baked goods more juicy and soft inside.

There is also moist convection, which creates steam inside the oven. As a result, baked goods do not dry out, pies and cakes rise well. In addition, the steam effect allows you to save oil and prepare healthy products without heavy frying.

Basically, electric oven models are equipped with different convection modes. In gas ovens this function is much less common. This is due to the fact that the gas model has its own specific design. An open fire in gas burners creates certain difficulties in creating forced circulation of heat.

Benefits of using convection ovens

The device has many advantages. The main ones are versatility and practicality. It is also worth knowing the following about the advantages of this choice:

Possibility of adjusting moisture and temperature inside the oven during the baking process using a partially or fully automated control system.
Products prepared in this device have high taste. In addition, the odors inside do not mix, which will allow you to cook several different types of baked goods at once and at the same time preserve their true aroma.
Operating the equipment does not require special skills, and the device consumes significantly less energy than its analogues.
The baked goods inside the oven do not have to be constantly checked for readiness - the device settings eliminate the need to perform these manipulations, and the transparent door allows you to visually monitor the cooking process without opening it.
Thanks to the uniform distribution of hot air flows inside the chamber, it is ensured that the same temperature is maintained in all parts of the prepared product, which contributes to maximum uniform baking.

Features of convection ovens

Installing household convection ovens allows you not only to solve the problem of preparing several portions of dishes at the same time, but also to save money on energy consumption (especially useful during the heating season). Features of the technology:

Even cooking. Hot air evenly heats dishes and allows you to maintain the temperature at a given level. Small dimensions allow you to use the equipment both at home and in public catering outlets for heating food and preparing semi-finished products. The temperature rises quickly. Within 20 minutes the maximum values will be reached. Thanks to this, dishes are prepared quickly. Now in your dacha you can forget about classic heating in the form of a wood stove and cook food using professional equipment.

Fans with reversible movement of professional household convection ovens work together with high-power heating elements, due to which the air flow circulates.

Traditional structures for heating country houses are mainly made of two materials - metal and brick, which is explained by their ability to withstand thermal effects well. To simplify the choice, you should consider both options in detail. Familiarization with all types of ovens will make it possible to select a system suitable for the specific needs of the consumer.

How to choose a convection oven

Kitchen equipment is selected depending on the number of levels, power and performance. Based on the type of control, a distinction is made between electromechanical and electronic ovens.

Electromechanical furnaces are easy to operate and cost less.

The presence of the steam humidification function will determine how much moisture the product will lose during cooking. Based on the type of steam humidification, a distinction is made between manual and automatic. In the first case, the cook independently chooses when to spray water by simply pressing a button.

In the second case, this process is automated. You can control the cooking through the transparent door with double heat-resistant glass

Please note whether the oven you are planning to purchase has a self-cleaning function. If we were talking about a convection oven for the home, then you could do it on your own. But in a professional kitchen, where every minute is precious, this procedure will save not only time, but also staff effort.

But in a professional kitchen, where every minute is precious, this procedure will save not only time, but also staff effort.

Taking into account all the above points, before purchasing, consider:

dimensions;
type of control;
method of vaporization;
number of levels;
electric or gas power supply;
the amount of food that can be cooked at the same time.
power;
additional features such as car wash.

There are some nuances in the operation of the furnace. Taking them into account, you will extend the service life of the combi oven:

A convection oven requires preheating, otherwise you may end up with dried out edges.
Fully loading the oven increases baking time.
The combi oven should be filled from the center, adding gastronorm containers evenly to the lower and upper levels.
The oven door must be closed when not in use.

Differences between the two methods

The above-mentioned production is divided into Bessemer and Thomas processes. The differences between them are in the main components of the converter linings.

The Bessemer steelmaking process allows for the use of low phosphorus and sulfur content. In the Thomas method, on the contrary, cast iron is melted using a high phosphorus content.

The essence of oxygen-converter production is the smelting of steel by lining and blowing oxygen from a liquid cast iron base. A water-cooling mold must be used for this.

Water cooling form

In the units, oxygen is supplied from below. This method is most common in Russia. Although in foreign countries a combined blowing method is often used. In metallurgy, the oxygen-converter smelting method is recognized as one of the most effective in several respects:

Reproduction of one steel-smelting unit exceeds the power of other methods by several tons.
In heavy-duty converters, reproduction reaches about 500 tons in 1 hour.
The costs are significantly lower than with other production.
Quite economical arrangement of any workshop, even regardless of the power of the melting units.
The simplicity of the process lies in the automation of the steel smelting method.

Due to the fact that pure oxygen is used, the resulting steel does not have a high nitrogen content. This allows the material to be used in a wide range of small industries

It is also important that comparative safety for health allows the use of mid-level specialists

Opportunity to provide employment to more people

What is convector heating called?

A convector heating system is a system in which heat is transferred from the heating element coolant through convection. That is, heat transfer is carried out by continuously moving air flows. Thanks to this, it is possible to heat the room evenly.

Heating is arranged as follows. Its main elements are convector heating radiators. At the bottom there is a heat exchanger in which a heated coolant constantly circulates, playing a major role in the heat exchange process. To make the contact area of cold air with the heater larger, it is equipped with flat metal ribs or tubes, which guide the flow of heated air.

Advantages and disadvantages

stoves, fireplaces with a water circuit, read our article.

Did you choose bimetallic radiators with bottom connections? Read how to choose here.

Heating convector device

So, cold air enters the heat exchanger, which, when heated, moves upward.

One of the advantages of such heating is that the air in the room can be heated quite quickly.

Convection in the oven: what is it?

The word “convection” itself comes from the Latin convectio, which literally translates as “delivery.” Convection is a special type of heat exchange process, the transfer of internal energy occurs in directed jets. Previously, in our kitchens there were standard ovens that were almost no different from each other. The bottom was equipped with a double bottom, inside of which the burners were located. After the oven had warmed up, baking trays with baked goods could be placed in it. The top of the pie or roast goose was browned only due to the movement of heated air masses. At the same time, a fairly common case is when dishes are unevenly baked or burnt. Sometimes I had to turn the pan over, risking ruining the dish.

Modern technology makes the work of housewives easier

In modern kitchens today, ovens with a convection function are increasingly found. In most cases, they have two or more heating elements on the top and bottom. But even in such models, food sometimes burns and is not cooked through. So what is it - convection mode in the oven? After all, the quality of cooking depends on it.

Convection is the process of movement of thermal masses inside the enclosed space of a cabinet. The attentive reader will definitely understand that even in the old type of technology it is necessarily present, since this process is absolutely natural. The movement of thermal energy allows food to bake faster. How uniformly and efficiently this happens is another question. Manufacturers of modern technology are trying to solve this problem.

Why is convection needed?

It is difficult to overestimate the advantages of the convection mechanism in an electric oven or other device. This technology is provided in most modern household ovens. First of all, it is indispensable when baking large pieces of meat, pies, making pizza, grilled chicken or toast.

Convection promotes uniform cooking of the dish, with its help you can avoid burning in one part of the dish and inadequate baking in another. Previously, to do this, you had to constantly turn the sheet over and change the position of the dish on it. The technology allows you to cook large pieces of fish or whole meat. In addition, convection adds a number of advantages:

rapid warming up of cold air, accordingly, saving time to obtain the desired temperature;
the appearance of a crispy crust, the ability to dry out an overly juicy dish;
possibility of simultaneous preparation of several dishes;
in the presence of moist convection, food is partially steamed, retaining more beneficial properties and minerals.

Principle of operation

The operating principle of convection is based on an active heat exchange process, which is achieved using a powerful fan located on the rear wall of the heating chamber. It accelerates the movement of air flows, thereby facilitating rapid heating of the oven volume.

Types of convection

Convection is classified according to various criteria. The complexity of the system comes first. It happens:

simple – represented by several fans;
complex - heating elements are equipped with built-in fans.

It is not very convenient for an ordinary user to use such a classification. The division based on the operating principle looks much clearer.

Natural. Air mass transfer occurs. The operating principle is based on the laws of physics. Heated air rushes up, cold air goes down
Forced. This principle is used in all modern electric stoves. Cheap products are equipped with only one fan. Expensive models have reinforced instruments. They are considered the most effective for cooking. In addition to creating powerful, uniform heating, they are capable of maintaining the required temperature for a long time.
Wet. A new model that has not yet become widely popular. Creates fine steam in an electric oven. It improves the rise of baked goods. The food will never be dry.

Good to know! The wet type allows you to cook food without adding oil. It is simply impossible to fry the dish.

Natural

It represents the usual distribution of thermal air flows and is not an additional option. In other words, such convection is present in every oven. It functions according to the usual physical principle. Warm air rises when heated, and cold air sinks. This leads to natural circulation of currents inside the oven. You won’t have to pay extra for this option, since it is not the “fruit” of engineering intervention, but it is this convection that is considered the least effective.

Oxygen converter melting process description

An oxygen converter is a pear-shaped steel vessel. Its interior is protected by resin-dolomite (base) brick. The capacity of the steelmaking unit varies from 50 to 350 tons. The vessel is located on axles and is capable of rotating around a horizontal axis, which allows you to freely pour cast iron into it, add other additives and merge metal with slag.

To obtain the final product, not only cast iron is poured into the converter, but also additives are added. These include:

scrap metal;
slag-forming materials (iron ore, lime, feldspar, bauxite).

The converter method with oxygen purging involves pouring cast iron heated to 1250–1400°C into the converter. By placing the converter in a vertical position, oxygen is supplied to it. As soon as blowing has begun, the remaining components that make up the slag are introduced into the molten cast iron. Mixing of cast iron with slag is carried out under the action of blowing.

A special feature of the main slag is its high content of calcium oxide and iron oxide, which contribute to the removal of phosphorus at the beginning of blowing. If the phosphorus content exceeds the required value, the slag is drained and a new one is added. Oxygen purging is completed when the carbon content in the final product meets a certain parameter. After this, the converter is turned over and the steel is drained into a ladle, where deoxidizers and other additives are added.

Process description

Many have never heard such a word, but it turns out that the problem of uneven heating of food in the oven is connected precisely with it. What is convection and what does it consist of? Convection literally translates from Latin as “transfer.” That is, this is a type of heat exchange in which energy is transferred through jets and flows.

Convection literally translates from Latin as “transfer.”

And in the oven there can be two types of convection: natural and forced. The natural process is when, from the moment the heating element is turned on, warm air rises and cold air descends. Then, gradually, warm and cold air masses mix, and as a result, the same temperature is established in the oven.

And in the oven there can be two types of convection: natural and forced.

What is convection in a forced oven? Let's take a closer look.

Wood burning heaters

Most ovens

, available on the market, run on wood fuel. Wood stoves are traditionally used as an additional source of heat. To increase the amount of heat generated, you can try burning more wood. Well-dried wood burns much better than wet wood.

Thus, in order to increase the amount of heat, it is advisable to use the so-called first (highest) grade of firewood (birch, ash, oak, maple, hornbeam). On average, one fill of the stove is enough for 4 hours of burning, but with good firewood, the room will warm up faster and with less wood consumption. The ability to heat only one room, without the possibility of connecting to the heating system of the house, in this case can be regarded as a disadvantage of this type of stove.

How different are wood stoves?

. Steel stoves are often smooth, without distinctive surface textures, suitable for modern home interiors. Cast iron stoves often resemble old stoves, are often produced with ornaments on the surface, and are suitable for classic interiors.

Steel and cast iron stoves

are made with built-in glass doors that allow you to control the fire burning in the evening and softly illuminate the room. For such doors, special heat-resistant glass is used. Glass with an extremely low coefficient of thermal expansion.

Convection ovens are often used to heat homes or cottages. The main difference between such ovens is the presence of grates or tubes for air circulation. Convection ovens, as their name suggests, operate on the principle of convection.

Cold air passes through the lower grilles while moving, heats up and rises, exits into the room through the upper outlets. Thanks to this movement, good air circulation is ensured and it becomes possible to heat not one, but several rooms, and not necessarily on the same floor.

A conventional wood-burning oven produces much less heat into the room than a convection oven does. Convection ovens are often lined with refractory tiles. Models of convection ovens are produced that operate on coal rather than wood. They have slightly smaller volumes and differ in the design features of the firebox. It should be noted that convection ovens can be automated.

Convection ovens can be of any size, which means they can be adapted to fit any room size. The minimum power of furnaces is 7 kW. The largest ones are about 16 kW. The external design of convection ovens is somewhat similar to steel and cast iron wood-burning ovens.

Basic practical tips for installing slabs

Please note that as much distance as possible should be maintained from the heater to combustible surfaces. Stoves must be placed on non-combustible surfaces, i.e.

e., ceramic tiles, metal, tempered glass, tin sheets

When choosing any type of stove, it is important to remember that for the stove to work efficiently, the chimney must be at least 100 - 130 mm in diameter

It is important to note that the chimney above the roof should be slightly higher than the ridge of the roof. Distance from the ridge to 1.5 meters

The chimney should protrude by 50 cm. If the chimney is located in the center of the ridge, the height of the pipe can be 70 cm above the roof. With the correct pipe height, good air circulation will be guaranteed.

Even more interesting articles

Menu HOME OUR SERVICES - apartment renovation - apartment design - search for a private master CALCULATOR OCCUPATIONAL SAFETY and HSE BUSINESS NEWS - land plots - real estate - purchase of real estate - rental sale CONSTRUCTION - foundations - waterproofing - walls and facade - roofing and attic - thermal insulation - windows and doors - floors and floor coverings - finishing work - engineering systems - building materials - ventilation and air conditioning - ceiling - heating systems - houses and cottages - window design - door design - repair work - water supply systems - design - construction technologies BATH SAUNA - features of Russian baths - construction and materials FIREPLACES STOVES - stoves, boilers, fireplaces ARCHITECTURE - ancient architecture - modern architecture - interior design - landscape design - decoration - furniture and furnishings - interior styles USEFUL - scientific and technological progress - builder's library - engineering equipment - machines - equipment and tools - services - construction equipment - energy saving ABOUT THE PROJECT SITE MAP

The principle of the Bessemer method

For the first time, mass production of liquid steel became possible in 1856 thanks to G. Bessemer, an inventor from England. He figured out how to heat metal to temperatures exceeding 1500°C. This is the temperature required to melt metal with a low carbon content.

Features and secrets of the process

This method differs from other methods of steel production in that it involves very high speeds. The entire method, as a rule, takes place in literally 14–24 minutes. High temperatures make it possible to set the instantaneous rate of dissolution of lime in slag contents.

Therefore, steel smelting in one converter, including the entire production process, does not take more than 30 minutes

It is important to note that the quality of the main process is directly affected by the uneven oxidation of each component contained in the aggregate

The leading principle of the oxygen converter process is determined by temperature control and changing the number of blowdowns. A necessary condition for the efficiency of smelting is the introduction of coolants such as iron ore, scrap metal, and limestone.

Dust waste is cleaned using a waste heat boiler. All waste gases from the smelting process enter the installation for their purification. All oxygen steel production is controlled by powerful modern computers.

It is worth noting that with bottom blowing, the specific volume of finished steel is much less than with top blowing. It is with the bottom method that the speed of obtaining finished steel is much higher.

Technologies for producing liquid steel

In addition, as for the finished metal, after all production work is completed, the result is 1–2% more efficient.

Additionally, during the process, the duration of purging is reduced and scrap melting is accelerated. All this allows you to set up a specific technological process at a lower height of the production building.

Requirements for furnaces

When choosing a stove based on the convection principle, it is important to pay attention to the main parameters. So you will be able to purchase the model that is optimal in terms of characteristics and cost.

No artisanal production. Choose only those stoves that are made by leading manufacturers. Never hesitate to demand all certificates even for products of a well-known brand.
Power. To prepare baked goods and dishes in certain quantities, appropriate power is required. Mini baking ovens have small parameters, but they are quite enough for home use. There is no point in paying for powerful devices if you do not plan to produce baked goods on a large scale for sale or open some kind of fast food.
Functions. Modern convection ovens are filled with all kinds of functionality. But experience shows that users often do not use even half of the oven’s capabilities. What's the point of giving money for something you won't use?
Doors. Look at the design of the stove door. The best convection ovens have a door made of two layers of glass with air trapped between them. This ensures natural convection, which prevents the outer glass from overheating. Plus, with this structure there is less heat loss.
Service centers. There is no point in repairing a convection oven yourself. It is better to choose manufacturers whose service centers are in your city.
Dimensions. Mini models are used for home use, while larger devices are suitable for production. It all depends on the purpose for which you are buying a convection oven.
Maximum heating temperature. Certain dishes require high temperatures to cook. Not all convection oven models are designed for them. Therefore, determine in advance what the stove will be used for and what temperature settings you need.
Appearance. Here, focus on your own tastes. There are a huge number of design options for convection ovens, so you will have plenty to choose from.

Types of convection

Modern technologies allow you not only to install a convector in the oven, but also to independently choose the type of convection.

Fan. The simplest option. “Drives away” air masses inside the oven, ensuring uniform heating.
Fan with ring heater. This device guarantees quick heating and reduced cooking time.
Reinforced convector. An ideal option for those who love dishes with a crust. Creates rapid air currents inside the oven, quickly “grabbing” the surface of the dish.
Double convection. In some ovens, two convectors are installed at once on different levels, which guarantees separate “processing” of each baking sheet.
Moist convection. This process will help you prepare healthy dishes, since they will not be fried, but stewed. This mode is ideal for baking, as well as for preparing healthy food with a minimum of salt and fat.