Industrial microwaves Industrial microwave oven. Thermal equipment of express class for a successful business

How would the fans healthy lifestyle life did not stand up for valuable properties and a storehouse of vitamins in salads from fresh vegetables, most people still prefer to combine them with hot meals. Compact, powerful, professional microwave ovens for restaurants and cafes from the WhiteGoods online store will heat up meat, side dishes, soups, pies, hot dogs, pizza, hot sandwiches and any cooked dishes in seconds. This is a reliable, convenient and affordable solution for catering enterprises of any level.

Microwave oven - a wise compromise in a limited space

Microwave ovens have become a reasonable compromise for cafes and catering outlets, where the shortage of production space barely allows you to place a refrigerator, coffee maker, etc., and not just an oven and, even more so, a hot shop. This compact appliance is able to meet the needs of customers in hot food and provide you with the right level of sales. Modern microwave ovens for restaurants from the line of advanced models combine innovative technologies, as a convection function, multi-level power adjustment, several defrost modes, preset programs for up to 360 recipes, an exhaust air purification system (catalytic converter), etc. Extensive functionality turns these small appliances into versatile equipment that will become a lifesaver in your restaurant, diner or cafe.

Thermal equipment of express class for a successful business!

Professional microwave ovens are absolutely indispensable equipment for grocery stores with hot snack stands, cafes without own kitchen, bistros, food courts based on semi-finished products and other ready-made food outlets. Due to the ergonomic shape of the case, the devices are easy to maintain and maintain hygiene standards. The main differences between a professional microwave oven and household models:

• increased power, thanks to which you will reduce the heating time by 42% -60% (hot sandwich / pizza in 4-9 seconds, cheeseburger - 20 seconds);
• uniform heating of dishes without drying out the edges or undercooking of the middle, inherent in household microwave ovens, will exclude marriage or dissatisfied reviews from restaurant visitors;
• increased useful volume of the working chamber;
• extended timer up to 60 min;
• many combined modes: microwave technology, grill, defrost, cooking, convection, etc.;
• The vitreous enameled durable restaurant microwave housing is impact-resistant and designed for heavy use in commercial kitchens. Plus durable reliable parts of the mechanism.

Thanks to stylish design and a rich color range, a microwave oven for a cafe will be an interesting addition to the interior and will take its rightful place on the bar counter. good model A professional microwave will help you pamper your visitors with both juicy meat or fish with a delicate taste, as well as fragrant pastries with a delicious golden crust, which will look fresh, like fresh from the oven.

Where to buy good microwave ovens for restaurants and cafes?

Flexibility of use and versatility, with the greatest preservation of usable space, explain the high demand for equipment of this class. High-speed, easy-to-operate restaurant microwave will save chefs time and create additional amenities in a professional kitchen. Prompt customer service will have a beneficial effect on the profitability of the institution.
In the WhiteGoods online store you can buy the most popular, universal, professional microwave ovens for cafes, restaurants and other catering establishments. Outstanding reliability and high efficiency are the hallmarks of professional equipment from the WhiteGoods catalog. Our microwave ovens will perfectly fit into the concept of any kitchen, save time and money!

Which is better: an infrared dryer for wood or a microwave analogue? To understand, you need to understand how they work, as well as compare the main indicators. What are we going to do.

Wood is a hygroscopic material that contains moisture and is able to absorb it from the outside. There are two types of sawn timber available for sale: having natural humidity and dried. The latter are more expensive, as they are ready for use immediately after purchase. Therefore, many sawmill owners are interested in purchasing wood dewatering equipment.

The market offers several options for wood drying installations. Today we will look at infrared dryers and microwave installations, we will understand the principle and parameters of their operation, we will decide how to organize the production process using them. Having detailed information about different types equipment, it will be much easier to decide which one will be optimal for a particular production.

Principle of operation

Infrared dryers suggest drying the wood by heating it with infrared rays. This method does not require the use of a coolant, the organization of a ventilation system and the presence of complex control automation. Drying does not lead to the occurrence of internal stresses and warping of the tree. It is possible to change the drying mode depending on the quality of the source material.

The principle of operation of the microwave dryer similar to a microwave oven. Drying occurs under the influence of microwave radiation: the moisture in the wood heats up and boils, overpressure, created by hot steam, squeezes it out. Excess moisture is removed by reversible fans.
The attenuation mode of the microwave wave makes it possible to regulate the drying temperature.

Appearance

Infrared dryers are a set of thermoactive cassettes, only 1.5 mm thick. These cassettes are stacked in a certain sequence in a pile of lumber prepared for drying.


microwave dryers have the form of a closed metal container, in most cases equipped with a mechanized trolley with an electric drive for more convenient placement of a stack of lumber inside the structure. Additionally, a control unit is installed.

Size and weight

One of the main advantages of infrared dryers is their portability. Standard thermoset cassette has a size of 1230 x 650 x 1.5 mm and a weight of 5.7 kg, which makes it easy to transport the entire set of wood drying equipment in the trunk passenger car. The weight of a set of 12 cassettes is 69 kg, and in the crate, together with the shield and cabling, it does not exceed 130 kg.

microwave installation has a much larger size and weight. So, the chamber, designed for drying 6-9 cubic meters of lumber, has a length of more than 6 meters, a width of 1 meter and a height of about 2 meters. At the same time, its weight is 9 tons, and the area required for installing the equipment is 3x17 m. To transport the microwave installation from place to place, you will need to use special equipment.

Autonomy of work

infrared dryer completely autonomous, with correct installation and connection, you do not need to constantly monitor the drying process.

microwave installation, in which the dehydration of the material is carried out by high frequency currents (915-2500 MHz), requires regular monitoring by the operator in order to avoid ignition of the wood inside the chamber.

Drying time

Naturally, the drying time of lumber depends on its moisture content in its original state and the type of wood.

By using infrared thermal cassettes any type of wood can be dried. Drying time to 8% moisture content of pine is 3-7 days. The thinner the boards and the higher the moisture content to achieve, the shorter the drying time.

Regarding microwave dryers It is known that the INVESTSTROY SHF-LES plant is capable of drying a pine beam 200x200 mm with a moisture content of 50-70% to 18% in 22 hours (after the material has cooled, the moisture content decreases to 10.2%).

Power supply

infrared cassettes work from an ordinary household power supply network of 220 V.

For work microwave dryer 380V, 50Hz power supply required.

Power and electricity consumption

Maximum plant power from infrared cassettes: 3.3 kW/m³. Electricity consumption during drying of 1 m³ of wood: 100-400 kWh.

Average power consumption microwave installations: 58 kW, and the specific energy consumption for the drying process is 200-230 kWh / m³.

Price

One of the most significant indicators when purchasing new equipment for work is its market value.

The prices for FlexiHIT infrared dryers are very democratic:

• equipment for drying 1 m³ of a three-meter board will cost 59,288 rubles;
• equipment for drying 1 m³ of a four-meter board will cost 69,329 rubles;
• equipment for drying 1 m³ of a six-meter board - 70,007 rubles.

Moreover, the prices are indicated for the entire set of equipment, which contains 12 thermoactive cassettes, a control panel, cabling and a crate.

In Russia microwave installations, as noted above, is produced by INVESTSTROY. Such a dryer costs from 1,300,000 rubles. In addition, when planning its acquisition, you need to take into account that the magnetron (a device that generates microwaves) is consumable. It will need to be replaced at least once a year. The cost of the magnetron is 150,000 rubles.

conclusions

It should be noted that both variants of the considered dryers are new technologies, but already successfully used in our country.

Doubtless convenience of infrared equipment is the possibility of its use both indoors and outdoors. outdoors, portability and low cost. Such equipment can be used in production and at home. The ease of installation allows you to fully assemble the dryer within one day, and if necessary, quickly disassemble it and transport it to another place. At the same time, the drying quality meets the most stringent requirements.


The advantage of microwave installation k is the ability to produce quick drying thick beams and rounded logs with a diameter of up to one meter. Their use is justified in production, where it comes to preparing for further use large workpieces. But on a less impressive scale this technology almost inaccessible due to the high cost and size.

Microwave installation for drying bulk materials.
Our company specializes in the development, design, engineering and testing of equipment in order to obtain a reliable and high-quality product for drying and heat treatment of bulk materials. Sample with maximum power 2 kW (power adjustable by software) and water cooling has successfully proven itself in the technological process. Can be used in various industries.

Microwave heating and its application:
Technological processing of a wide variety of objects almost always includes heat treatment and, first of all, heating or drying. With traditional methods of heating and drying (convective, radiation and contact), the object is heated over the surface. If the thermal conductivity of the object is low, which is the case with dielectrics, then the heat treatment of the object occurs slowly, with local overheating of the heating surface, which may cause the surface to burn, causing internal mechanical stresses. All this can ultimately lead to the failure of the object.
Microwave is the heating of an object by the energy of an electromagnetic field of microwave frequencies. An electromagnetic wave, penetrating into an object, interacts with charged particles. The combination of such microscopic processes leads to the absorption of the field energy in the object. Full description effect can only be obtained with the help of quantum theory. Let us limit ourselves to taking into account the macroscopic properties of the material medium described by classical physics.
Depending on the location of the charges in them, the molecules of the dielectric medium can be polar and non-polar. In some molecules, the arrangement of charges is so symmetrical that in the absence of an external electric field their electric dipole moment is zero. Polar molecules have some electric dipole moment even in the absence of an external field. When an external electric field is applied, non-polar molecules are polarized, that is, the symmetry of the arrangement of their charges is violated, and the molecule acquires a certain electric moment. Under the action of an external field, polar molecules not only change the magnitude of the electric moment, but also turn the axis of the molecule in the direction of the field. A distinction is usually made between electronic, ionic, dipole, and structural polarizations of a dielectric. On the microwave the largest specific gravity have dipole and structural polarizations, so that heat release is possible even in the absence of conduction current.

Microwave devices for technological purposes operate at frequencies established by international agreements. For heat treatment in the microwave range, electromagnetic oscillations at frequencies of 433, 915, 2375 (2450) MHz are most often used.
The table gives information about the depth of penetration of an electromagnetic wave into some of the lossy dielectrics.

Depth of penetration of an electromagnetic wave In a dielectric with losses at 20-25Co

So, if instead of traditional methods of heating, heating is used using the energy of microwave oscillations, then due to the penetration of the wave into the depth of the object, this energy is converted into heat not on the surface, but in its volume, and therefore it is possible to achieve a more intensive increase in temperature with greater uniformity. heating compared to traditional heating methods. The latter circumstance in some cases leads to an improvement in the quality of the product. Microwave heat treatment has a number of other advantages. Thus, the absence of a traditional coolant ensures the sterility of the process and the inertia of heating control. By changing the frequency, it is possible to achieve heating of various components of the object. Microwave electrothermal installations occupy an area smaller than similar installations with a traditional energy drive, and have less harmful effects on environment at best conditions labor of service personnel. Microwave installations and their working chambers.

For any purpose of the microwave electrothermal installation, it has block diagram shown in Figure 1.

A prototype of a microwave oven manufactured for Polysorb LLC

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It is possible to single out the main areas of application of microwave heating - food, rubber and textile industries. Here important role characteristics such as the efficiency of the process, the possibility of automation and the high quality of the product play. There are prospects for the introduction of microwave heating and drying in the pharmaceutical industry, wood processing and Agriculture. The use of fast heating technology in canteens, hospitals, schools, etc. is expanding, mass use microwave ovens in everyday life is already well known to our readers.
The effect of microwave heating is based on the absorption of electromagnetic energy in dielectrics. Microwave fields penetrate to a considerable depth, which depends on the properties of the materials. Interacting with matter at the atomic and molecular level, these fields affect the movement of electrons, which leads to the conversion of microwave energy into heat.
Microwave energy is a very convenient source of heat, which has undoubted advantages over other sources in a number of applications. It does not introduce pollution when heated, when using it, there are no combustion products. In addition, the ease with which microwave energy is converted into heat allows very high heating rates to be obtained without damaging thermomechanical stresses in the material. The generator equipment is fully electronic and operates almost without inertia, due to which the microwave power level and the moment of its supply can be changed instantly. The combination of microwave heating with other heating methods (steam, hot air, infrared radiation, etc.) makes it possible to design equipment to perform various functions, i.e. Microwave heating allows you to create new technological processes, increase their productivity and improve product quality. A proper assessment of the applicability of microwave energy in special processes requires a detailed knowledge of the properties of the material at various frequencies and at all stages of the process. The absorbed power and the depth to which this power penetrates are determined by three factors: permittivity, frequency, and geometry of the microwave system.
The permittivity of lossy materials is a complex value:
,
where ε is the relative permittivity, tgδ = ε1 / ε is the dielectric loss factor of the material, or the loss tangent.
The penetration depth in microwave energy is understood as the distance d at which the power density decreases to 37% of the value on the surface, i.e. in other words, 63% of the initial energy of an electromagnetic wave is absorbed in the material and converted into heat. For a small value of tgδ, the penetration depth is determined by a simple expression:

where d is the penetration depth, cm; f is the frequency, GHz.
The power absorbed per unit volume will be, W/cm3:
Р = 2.87  10-4 Е2f  tgδ,
where E is the electric field strength, V/cm; f is the frequency, GHz.
The calculated values ​​of the depth of penetration of microwave energy into food products at a widely used frequency of 2.45 GHz are given in Table 1. If tgδ decreases with temperature, then the heating process is stable (microwave energy absorption decreases with temperature). Such automatic temperature limitation occurs when dielectrics are heated, in which the losses are due to the water content with its special dependence of dielectric properties on temperature.
Heating by infrared or light sources operates, in comparison with microwaves, at higher (by about 2–3 orders of magnitude) frequencies. Accordingly, the penetration depth decreases and only the surface of the processed object is heated. The rest of the volume receives heat only due to the slower heat conduction process. This can lead to thermomechanical overstresses and loss of material quality. Where time is of the essence (cooking, drying or reheating), microwaves have a decisive advantage over heat radiation. For example, when cooking vegetables or fruits, microwave heating helps to maintain a fresh look and taste, and the vitamin content is slightly reduced.
Cost-effective microwave heating during drying hard rock wood, since the temperature rise at a rate of up to 1000°C/s can be realized at a field strength of 5 kV/cm.
Compared to infrared heating, the use of microwaves has great advantage– almost instantaneous switching on and off, as well as precise temperature control. High power density and better focusing result in great energy savings. Useless radiation and the need for concomitant cooling of surrounding parts are eliminated.
The integration of an electronic microwave generator into an automatic production line is quite simple due to its reasonable cost, economy and compactness. A combination with other types of processing is also possible. For example, when processing poultry carcasses, microwaves and steaming are used simultaneously.
Of course, factors such as product quality, processing speed, space requirements, energy cost, and investment need to be accurately assessed for a particular application to determine if microwave heating will be superior to conventional methods.

Industrial magnetrons
as generators. high power magnetrons and klystrons are used. Due to the higher efficiency below 50 kW, magnetrons dominate. The two most commonly used frequencies are 915 and 2450 MHz. Since the frequency of 915 MHz may not be used in all cases, the frequency of 2450 MHz is usually considered optimal in international practice. Table 2 gives an idea of ​​modern Russian magnetrons produced by CJSC NPP Magratep in comparison with foreign devices.
The M-116-100 magnetron (Fig. 1) is used in fish defrosting, rock softening and in other cases where an increased penetration depth into the material is required.

The world's only M-137 magnetron with a power of 50 kW at a frequency of 433 MHz (Fig. 2) was successfully used in experimental facilities for soil softening in Yakutia. Such a low operating frequency provides the required depth of penetration of microwaves into frozen rocks.
The M-168 magnetron with a power of 5 kW (Fig. 3) is widely used in installations for rubberizing cables, vulcanizing rubber parts, and polymerizing plastic.
Microwave Processing Plants
Microwave heating processes are divided into two groups: continuous processes and batch processing. In continuous processes, for example, on a conveyor, the "raw" material continuously passes through the processing zone, while the load at the output of the microwave generator remains practically unchanged. When processing in batches, the heated material is in the processing zone until the required temperature is reached, therefore, with a change in temperature, the permittivity and loss factor change significantly. This leads to a change in the load (and within a wide range) for which the microwave generator must operate. Even in well-used economical installations, VSWR loads can exceed 4. In this case, magnetrons are preferred due to their ability to operate on a load with a high VSWR.

Fig.4. Scheme of an installation for heating oil products in railway tanks (Elvis enterprise, Nizhny Novgorod). Microwave generator descends from above

The new technology of high-intensity heat treatment consists in heating the grain in a combined way: first, convectively - to a temperature of 95 ° C and then - in an electromagnetic microwave field to a temperature of 120–150 ° C (Fig. 6). With the rapid heating of the grain "from the inside" boiling occurs capillary moisture, an increase in the partial pressure of water vapor and the rupture of starch shells. At the same time, indigestible starch is broken down into dextrins - easily digestible forms. With this processing of grain, containing about 40% starch, its nutritional value increases by 20-30% and taste improves.
Other promising microwave technologies are drying, disinsection and disinfection of grain, thermal stimulation of grain during presowing treatment, improvement of baking qualities, and a number of others. Pasteurization and sterilization of liquid food products using microwave energy. These methods are distinguished high performance process and compact installations. Among other things, microwave material processing units have the ability to accurately maintain technological regimes, which makes it possible to obtain high-quality products, for example, during drying medicinal herbs(Fig. 7).
In some cases, one has to deal with such large-sized objects that it is impossible to use resonators or pipeline processing. Then, for example, the package wooden beam for drying, it is loaded into a box, inside which it is processed by microwave energy using a system of special waveguide-slot emitters (Fig. 8).
Radiant systems are particularly suitable for heating thin films or microwave hyperthermia of malignant neoplasms.
The essence of the method lies in heating the tumor with the help of electromagnetic radiation to a temperature level of 42–44°C. The advantages of microwave hyperthermia are that the affected area is heated from the inside, while heating the tissues is uniform, without damage. skin. The modern unit for local microwave hyperthermia "Yakhta-3" (FSUE "NPP "Istok", Fryazino) allows you to create and maintain a zone of hyperthermia in a tumor of almost any configuration for a long time with minimal impact on the surrounding organs and tissues. Microwave hyperthermia is used as V independent form, and as a means of enhancing the effect of chemotherapy and radiation therapy.

Literature
1. Microwave energy / Trans. from English. Ed. Shlifera E.D., vol. 2. - M .: Mir, 1971.
2. IR, 2008, No. 12;