Description
The industrial microwave unit WSZ is a tunnel type sterilizer. Typically, heat transfer occurs as follows: the surface of the equipment transfers heat to the surface of the material, which then transfers heat to interior material. Thermal conduction occurred through convection or radiated wave. This method has always had the negative factor of slowly reaching the desired temperature for sterilization. Microwave installations emit in such a way that they react directly and quickly to existing bacteria in the material. Thermal and non-thermal effects are both effective in this case, thus shortening the processing time. The sterilization process, depending on the properties of the material, usually takes 3-5 minutes. The sterilization temperature in the chamber ranges from 70 ℃ to 90 ℃.

Application
This equipment is used to sterilize and dry the following types of materials: spices, food additives, protein powder, meat products, seafood, fruits, legumes, vegetables, mushrooms, wheat, starch, compound feed and so on, spreading to the most various industries, including food, pharmaceutical, agricultural.

Peculiarities
1.Has an automatic temperature control system, a microwave density control system, a heating time control system, an alarm system, and a video surveillance system.
2.Takes up small space, instant heating speed, smooth heat transfer, good maneuverability and controllability, easy operation, energy saving and low cost.
3.Transformer can be with different kinds cooling, including water, air and self-cooled. Able to work 24 hours in a row, continuously.
4.Leakage rate meets UL national and American quality standards.

Specifications industrial microwave installation

Yangzhou Yutong Drying Equipment Co., Ltd is an industrial microwave oven manufacturer and supplier in China. In addition, we also supply mixing, granulating equipment, extractors and concentrators. The enterprise has received an AAA credit rating from the Jiangsu International Credit Assessment Company. Our industrial microwave systems have long been trusted by manufacturing companies.

The main areas of application of microwave heating can be identified - food, rubber and textile industries. Here important role characteristics such as process efficiency, automation capability and high product quality are at 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; the massive use of microwave ovens in everyday life is already well known to our readers.
The microwave heating effect is based on the absorption of electromagnetic energy in dielectrics. Microwave fields penetrate to a considerable depth, which depends on the properties of materials. Interacting with matter at atomic and molecular level, these fields affect the movement of electrons, which leads to the conversion of microwave energy into heat.
UHF energy is a very convenient source of heat, which in a number of applications has undoubted advantages over other sources. It does not introduce contamination when heated, and when it is used, 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, while no destructive thermomechanical stresses arise in the material. The generating equipment is completely electronic and works practically inertialessly, due to which the microwave power level and the moment of its supply can be instantly changed. 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. To correctly assess the applicability of microwave energy in special processes detailed knowledge of material properties at various frequencies and at all stages of the process is required. The absorbed power and the depth to which this power penetrates are determined by three factors: dielectric constant, frequency and geometry of the microwave system.
The dielectric constant of lossy materials is a complex quantity:
,
where ε is the relative dielectric constant, tgδ = ε1 / ε is the dielectric loss factor of the material, or the tangent of the loss angle.
The depth of penetration 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 the electromagnetic wave is absorbed in the material and converted into heat. For a small value of tgδ, the penetration depth is determined simple expression :

where d is the depth of penetration, cm; f - frequency, GHz.
The power absorbed per unit volume will be, W / cm3:
P = 2.87 10-4 E2f tgδ,
where E is the electric field strength, V / cm; f - frequency, GHz.
The calculated values ​​of the depth of penetration of microwave energy into food products at the widely used frequency of 2.45 GHz are given in Table 1. If tanδ decreases with temperature, then the heating process is stable (absorption of microwave energy decreases with temperature). This automatic temperature limitation occurs when dielectrics are heated, in which losses are due to the water content with its special dependence of dielectric properties on temperature.
Heating by infrared or light sources works, 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 overvoltages and loss of material quality. Where time is of the essence (cooking, drying or reheating), microwaves have a decisive advantage over radiant heat. For example, when cooking vegetables or fruits, microwave heating helps to maintain a fresh look and taste, and the vitamin content is slightly reduced.
Microwave heating is economically effective when drying hard wood, since a temperature rise at a rate of up to 1000 ° C / s can be realized at a field strength of 5 kV / cm.
Compared with infrared heating The use of microwaves has a great advantage - almost instant switching on and off, as well as precise temperature control. High power density and better focusing result in great energy savings. Waste 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 easy due to its reasonable cost, economy and compactness. A combination with other treatments is also possible. For example, when processing poultry carcasses, microwaves and steaming are used simultaneously.
Of course, for a particular application, factors such as product quality, processing speed, space required, energy cost, and investment must be carefully evaluated to determine if microwave heating will be superior to traditional methods.

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

The world's only magnetron M-137 with a power of 50 kW at a frequency of 433 MHz (Fig. 2) was successfully used in experimental installations for soil softening in Yakutia. Such a low operating frequency provides the required depth of microwave penetration into the frozen rocks.
Magnetron M-168 with a power of 5 kW (Fig. 3) is widely used in installations for rubberizing cables, vulcanizing rubber parts, polymerizing plastic.
Microwave treatment 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 on the output of the microwave generator is 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 dielectric constant and the loss factor change significantly. This leads to a change in the load (and within wide limits) for which the microwave generator must operate. Even in waste economical installations, the VSWR of the load can exceed 4. In this case, magnetrons are preferred because of their ability to operate on a load with high VSWR.

Fig. 4. Installation diagram for heating oil products in railway tanks ("Elvis" enterprise, Nizhny Novgorod). The microwave generator goes down from the top

The new technology of high-intensity heat treatment consists in heating the grain in a combined way: first, convectively - up to a temperature of 95 ° C and then - in an electromagnetic microwave field up to a temperature of 120–150 ° C (Fig. 6). With the rapid heating of the grain "from the inside", capillary moisture boils, the partial pressure of water vapor increases, and the starch shells break. At the same time, starch that is difficult to digest is broken down into dextrins - easily digestible forms. With such processing of grain, which contains about 40% starch, its nutritional value increases by 20-30% and the palatability improves.
Other promising microwave technologies are drying, disinfestation and disinfection of grain, thermal stimulation of grain during pre-sowing treatment, improvement of baking qualities, and a number of others. Pasteurization and sterilization of liquid food products using microwave energy are possible. These methods are distinguished by high productivity of the process and compactness of installations. Among other things, installations for microwave processing of materials have the ability to accurately maintain technological modes, which makes it possible to obtain high quality products, for example, when drying medicinal herbs (Fig. 7).
In some cases, one has to deal with such large-sized objects that resonators or conveyor processing cannot be used. Then, for example, the package timber for drying, it is loaded into a box, inside of which it is processed with microwave energy using a system of special waveguide-slot emitters (Fig. 8).
Radiant systems are especially suitable for heating thin films or microwave hyperthermia of malignant neoplasms.
The essence of the method consists 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 zone of influence is heated from the inside, heating of the tissues is uniform, without damaging the skin. Modern installation for local microwave hyperthermia "Yakhta-3" (FSUE "NPP" Istok ", Fryazino) allows creating and long-term maintenance of a zone of hyperthermia in a tumor of almost any configuration with minimal impact on surrounding organs and tissues. independent form and as a means of enhancing the effect of chemotherapy and radiation therapy.

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

Microwave dryer 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. A sample with a maximum power of 2 kW (power controlled by software) and water cooling has successfully proved itself in technological process... Application in various industries is possible.

Microwave heating and its application:
Technological processing of a wide variety of objects almost always includes heat treatment and primarily 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 is why this surface may burn, and internal mechanical stresses may arise. All this can ultimately lead to the failure of the facility.
Super-high-frequency is the heating of an object by energy. electromagnetic field ultra-high frequencies. An electromagnetic wave, penetrating an object, interacts with charged particles. The combination of such microscopic processes leads to the absorption of field energy in the object. A complete description of the effect can be obtained only with the help of quantum theory. We restrict ourselves to taking into account the macroscopic properties of the material environment described by classical physics.
Depending on the location of 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 a certain 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 rotate the axis of the molecule in the direction of the field. Usually, a distinction is made between electronic, ionic, dipole and structural polarization of a dielectric. At microwave frequency the greatest specific gravity have dipole and structural polarization, so that heat release is possible even in the absence of a conduction current.

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

Depth of penetration of an electromagnetic wave in a dielectric with losses at 20-25Со

So, if, instead of traditional heating methods, heating using the energy of microwave oscillations is used, 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 intense increase in temperature with greater uniformity heating compared to traditional ways heating. 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 heat carrier ensures the sterility of the process and the inertia-free heating control. By changing the frequency, it is possible to achieve heating of various components of the object. Microwave electrothermal installations occupy a smaller area than similar installations with a traditional energy drive, and have less harmful effect on environment at better 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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A professional microwave oven has a number of significant differences from household appliances, and this should be taken into account when deciding to buy a microwave oven for a restaurant or cafe. It is important to understand that household apparatus not designed for long and frequent work cycles, does not have enough power to solve professional and production tasks, does not always correspond to strict hygiene requirements applied to. Let's pay attention to a number of the most important parameters of professional microwave ovens for catering.

• The power of the magnetron in such models can be very high, reaching up to 3 kilowatts, and this reduces the heating time by up to 40 - 60% in comparison with a household stove. So, it will take no more than 9 seconds to bring a hot sandwich to serving temperature, for a cheeseburger - about 20 seconds.
• The increased power makes it possible to evenly process the workpiece, prevent the appearance of dry edges, cold middle - this is essential to reduce scrap.
• The working space of a professional microwave oven is usually large, the chamber volume can be up to 35 liters, and this is a serious application for mass production in public catering. There is no rotating element with a plate in the working chamber, which only takes up space from the point of view of professional use.
• The duration of the working cycle can be up to 60 minutes, the number of cycles per day is limited not to five or six inclusions, but to hundreds. At the same time, the electronic programmer is capable of operating in many complex modes, and the operator can set complex sequences of operations for the device.
• Inner space the working chamber is made of of stainless steel, which corresponds to the hygienic standards for catering establishments.

The principle of operation and types of professional microwave ovens

The principle of operation of a professional microwave oven is based on resonance that occurs in conducting molecules when they enter the region of microwave electromagnetic radiation. This defines essential feature this heating method is surface heating. Unlike traditional cooking methods of heat treatment of products, heating occurs not due to the influx of heat from the outside, but directly inside the surface layer.

It is necessary to take into account some of the features of the physics of this process and the misconceptions associated with it. Electromagnetic induction leads to the appearance of a current only on the surface of the conductor, which means that the active process of resonance and heating occurs at a shallow depth, and the statement “the microwave heats the product from the inside” is deeply mistaken. It would be more correct to say that the product heats up by itself, and not under the influence external source heat. Heat spreads from the surface layer inward.

Heating efficiency depends on the presence of water molecules in the product. The wet surface layer will warm up faster. Therefore, when a large piece of meat is thawed, its edges may begin to “cook”. Drops of fat in the working chamber can become active conductors of current, and this will lead to the appearance of a superconducting plasma that looks like sparks and a blue glow in a microwave oven, and ultimately to a breakdown of the magnetron.

A professional microwave oven allows you to regulate the heating process not due to pauses in the operation of the magnetron (like a household electric stove with frequent on and off switching), but due to the use of an inverter in the design, it changes the power of the radiation itself. This is very important for professional cooking, since it gives you a real opportunity to control the process of cooking, defrosting or heating food.

These physical features are the main difference between microwave processes and thousand-year-old traditional culinary methods. That is why manufacturers of microwave ovens began to expand their functionality and build into their products various devices for traditional methods cooking. The result of such developments was the emergence of complex devices with additional functions.

• Microwave oven with convection feeds into working chamber hot air, thus allowing cooking traditional dishes baking method, as in.
• The microwave oven with grill is equipped with heating elements for working in a commercial kitchen - frying meat and fish using direct heating, how in professional grills . Heating elements can be located in different points of the working chamber.
• Microwave ovens with a programmer are the most powerful devices that work for a long time with a built-in microprocessor. They perform many functions, are able to independently carry out the entire cycle from defrosting to complete cooking and signal the end of the process. As a rule, such equipment is equipped with a display for full information and control. Furnaces of this type are designed for a three-phase connection, due to which they provide an output power of up to 3 kilowatts, while working with two magnetrons at the command of a microprocessor.
• Industrial microwave ovens - they are not used in restaurant business, but exist as a class of equipment for various industries, including mechanical engineering.

Offers to buy professional microwave ovens - in our catalog you will find devices with various parameters and capabilities, from a simple device for warming up ready meals in a cafe to a high-power oven with a full range of built-in functions, convection, grill, program control.

Microwave ovens and heating equipment for restaurants from "RestaurantKomplekt"

For the convenience of our customers, we have developed our own logistic scheme - the equipment can be received at or picked up at as soon as possible at. If there is no equipment in the regional warehouse for your order, we will deliver from Moscow at our own expense.

We offer professional microwave ovens for catering. full set... If necessary, it is carried out on site. A range of professional catering microwave ovens at your disposal

• SIRMAN
• AIRHOT
• MERRYCHEF
• SAMSUNG
• BECKERS
• MENUMASTER
• HURAKAN

With a chamber volume of 17 to 35 liters and a capacity of up to 3 kilowatts.