Industrial microwave installations for bulk materials. Infrared or microwave dryer for drying wood: choosing equipment for work. The principle of operation and types of professional microwave ovens

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 appliance not designed for long and frequent cycles of work, does not have enough power to solve professional and production tasks, does not always meet the stringent hygienic requirements applied to. Let's pay attention to a number of the most important parameters of professional microwave ovens for public 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% compared to 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.
• Increased power makes it possible to evenly process the workpiece, prevent the appearance of dry edges, unheated middle - this is essential to reduce rejects.
• Working space a professional microwave oven is usually large, the volume of the chamber can reach up to 35 liters, and this is a serious application for mass production in catering. There is no rotating plate element in the working chamber, which only takes up space in terms of professional use.
• The duration of the working cycle can reach 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 a variety of complex modes, and the operator can set complex sequences of operations for the device.
• The inner space of the working chamber is made of of stainless steel, which complies with hygiene 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 the resonance that occurs in current-conducting molecules when they enter the region of microwave electromagnetic radiation. It defines the most important feature This method of heating is surface heating. Unlike traditional methods of heat treatment of products for cooking, heating occurs not due to the influx of heat from the outside, but directly inside the surface layer.

Some features of the physics of this process and the misconceptions associated with it should be taken into account. Electromagnetic induction leads to the appearance of 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 erroneous. It would be more correct to say that the product heats up itself, and not under the influence of external source heat. The heat propagates from the surface layer inwards.

The heating efficiency depends on the presence of water molecules in the product. Wet surface layer warm up faster. Therefore, when defrosting big piece meat, 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), but due to the use of an inverter in the design - it changes the power of the radiation itself. For professional cooking, this is very important, because it gives a real opportunity to control the process of cooking, defrosting or heating food.

These physical features are the main difference between microwave processes and millennial methods traditional for cooking. That is why manufacturers of microwave ovens have begun to expand their functionality and integrate various devices for traditional cooking methods into their products. The result of such developments was the emergence of complex devices with additional functions.

• The microwave oven with convection supplies hot air to the working chamber, thus allowing you to cook traditional dishes baking method, as in.
• The microwave oven with a grill is equipped with heating elements for work in a commercial kitchen - frying meat and fish using direct heat, as in professional grills. Heating elements can be located at 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, they are able to independently carry out the entire cycle from defrosting to complete cooking of the dish and signal the completion of the process. As a rule, a display is installed on such equipment 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 on microprocessor commands.
• 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 simple apparatus to warm 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 thermal equipment for restaurants from "RestoranKomplekt"

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

The professional microwave ovens offered by us for catering have full set. Performed on site if necessary. A range of professional microwave ovens for catering

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

With chamber volume from 17 to 35 liters and power up to 3 kilowatts.

Description
Industrial microwave WSZ is a tunnel type of sterilizers. Typically, heat transfer occurs as follows: the surface of the equipment transfers heat to the surface of the material, which further transfers heat to inner part material. Heat conduction occurred with the help of convection or a radiated wave. This method has always had the negative factor of slowly reaching the desired temperature for sterilization. Microwave units radiate in such a way as to respond directly and quickly to existing bacteria in the material. The thermal and non-thermal effects are both effective in this case, thus reducing the processing time. The sterilization process, depending on the properties of the material, usually lasts 3-5 minutes. The sterilization temperature in the chamber varies 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 a wide variety of industries, including food, pharmaceutical, agricultural.

Peculiarities
1. It has automatic temperature control system, microwave density control system, heating time control system, alarm system, and video surveillance system.
2.Takes up little space, instantaneous speed heating, even heat transfer, good maneuverability and controllability, easy operation, energy saving and low cost.
3.Transformer can be with various types cooling, including water, air and self-cooled. Able to work 24 hours in a row, continuously.
4. Leak rate complies with national and American UL quality standards.

Specifications industrial microwave installation

Yangzhou Yutong Drying Equipment Co., Ltd is a manufacturer and supplier of industrial microwave equipment in China. In addition, we also supply mixing, granulating equipment, extractors and concentrators. The enterprises received a credit rating of “AAA” from Jiangsu International Credit Assessment Company. Our industrial microwave units have long been trusted by manufacturing companies.

Industrial microwave ovens used in enterprises Catering for rapid heating, as well as cooking and defrosting of various products and ready-made meals using a high-frequency current of an electromagnetic field. Industrial microwave ovens operate in the following modes:

• microwave,
• convection,
• grill.

In addition, they can be combined for a more varied preparation of common dishes. Today, mechanical, electronic, as well as electromechanical control of microwave ovens is used.

As for the differences between professional and household equipment, in general, professional ovens are similar to household ones, but they cook, reheat and defrost food much faster and in large quantities. That is why most entrepreneurs are trying to buy branded food equipment, and not be content with much less productive household counterparts.

In addition, industrial microwave ovens are more reliable and durable than domestic ones. They are able to withstand intensive use, that is, they can work continuously for a long time. Often they are equipped with additional programs, and almost always have a larger internal chamber.

Another one distinguishing feature professional microwave ovens from household ones - ultra-reliable shielding. It is for this reason that such furnaces practically do not emit harmful electromagnetic waves. In the door mechanism reinforced construction, and the professional microwave ovens themselves are built very rationally, which makes it possible to most effectively use the working volume of the chamber.

Microwave ovens are not included necessary equipment for professional kitchens, since they are not so actively involved in the cooking process. But in Lately professional microwave ovens are increasingly used in bars, restaurants and fast food establishments with high traffic.

Such equipment is absolutely indispensable today for restaurants and cafes that offer full meals. Industrial microwave ovens work successfully in large kitchen shops of hotels and airports.

Professional furnaces, like any other similar equipment, are characterized by increased wear resistance and highest performance. They are designed for really tough operation, and in almost round the clock. The quality of such equipment is ensured by an extremely careful selection of structural materials with excellent performance characteristics. Also a big advantage professional ovens is the greater mobility of heating and defrosting dishes, which becomes an indispensable quality when you need to increase the throughput of a certain catering enterprise.

Compared to other professional equipment, the advantage of microwave ovens is the economy in power consumption, since most models are powered by single-phase network current and bring products to readiness in a very short time. Most microwave ovens are made of stainless steel, lined with plastic or the same stainless steel on the outside. The inner chamber is made without seams, which greatly facilitates its care.

microwave The setup consists of a microwave chamber, a magnetron, a waveguide, a power supply unit, a cooling system, and various devices security.

From the magnetron, through a rectangular waveguide, electromagnetic radiation enters the microwave chamber. The heat removal from the magnetron is air system cooling made with the help of a fan and air ducts passing through the microwave chamber. Thus, the body in the chamber is heated not only by microwaves, but by the allotted warm air from the magnetron. Further, the air in the chamber is saturated with water, that is, it turns into steam and exits through non-radiated holes (transcendental waveguides) to the outside. The power supply of the magnetron is high-voltage and consists of a diode, a capacitor and a transformer. To achieve normal operation without excessive radiation to the outside, interlock microswitches (from 2 to 5 pieces) are used to confirm that the door of the microwave chamber is closed tightly. If there is lighting in the chamber, then an incandescent lamp is usually used inside the duct. Using the control unit, made in the form of an electromechanical timer or an electronic unit, the operating mode is set in the microwave chamber. Many furnaces have thermal relays located on the magnetron and on the chamber on the outside to prevent overheating and failure.

Figure 1.7.1. The design of the microwave installation

1.7. 2 The principle of microwave heating

In a furnace, the body can be heated by the principle of "dipole shift", which occurs in materials that contain a polar nye molecules. The energy of electromagnetic waves sets in motion molecules that have a dipole moment. Thus, the temperature of the material increases.

Most household and industrial microwave ovens operate at 2450 MHz and at 915 MHz.

Based on practical and design considerations, the indicated frequency was chosen:

The magnetron must have a power of over 500 W, the required efficiency, cost and certain dimensions;

The frequency must meet the international and national standards for allowed frequencies.

The depth of penetration of microwaves into the working fluid should be about a few centimeters. (The higher the frequency, the lower the penetration depth).

Conveyor-type microwave devices

Microwave through-type devices are used in the production of heat-insulating materials using dry and liquid silicates, for example, from a mixture of hydroaluminosilicates bound by liquid glass. There are devices designed for fast temperature treatment (blowing) and for slow one. Such an abundance of heat treatment rates gives a similar set of bubble heat-insulating substances, with different properties. Microwave heat treatment devices are made in such a way that inside them, if the radiation has not been absorbed by the material, it is repeatedly reflected from the walls and still reaches its goal. The basic rule for uniform microwave heating -- multiple microwave generators low power(from 0.6 kW to 0.85 kW) with air cooling, which are located inside in a strict order. At an operating frequency of 2450 MHz, microwave radiation generators have a waveguide output with a cross section of (72 34) mm. Figure 3 shows the design of a device for microwave heat treatment for the manufacture of heat-insulating plates with a size of 60060050 mm from expanded vermicuite bonded with liquid glass.

The raw material is installed on the lower collapsible tray made of fluoroplastic, which transmits microwave radiation, and enters the installation, where it is emitted. When passing through the chamber, the processed substance becomes lighter by 30-40%, while increasing its volume from two to six times due to the fact that liquid glass swells.

At the same time, for these microwave installations, the efficiency of the radiated energy reaches 90%, taking into account the heating losses environment and internal walls of the device. On this stage such a device can pass through itself 117 plates in an eight-hour working day, while the microwave power is 27 kW. To achieve this power, it is necessary to install 45 low power generators (0.6 kW).

The layout of sources on the chamber is shown in fig. 1.7.3. .

Rice. 1.7.3.

1 - body; 2 - source of microwave energy; 3 - fan;

4 - ventilation window; 5 - conveyor belt; 6 - flange.

Microwave devices of periodic type

A microwave installation of a periodic type, for example, is a device for drying wood. On the walls of the chamber are installed generators of microwave radiation, each of which is 0.6 kW.

Waveguide energy outputs are installed in microwave generators, each of which has a cross section of 72mm (2450 MHz) and also mm (915 MHz). Since the generators are placed along the walls in this way, the wood heats up evenly.

Technological modes of wood drying were made for all generators, taking into account multiple reflections from the side surfaces inside the microwave unit. The calculation of temperatures at each point of the chamber was made both for the start of the process, when the moisture content of the raw material is maximum, and for the end, when the moisture content of the material is much less. The condition under which the temperatures of all points of the chamber were calculated was that the uneven distribution of the temperature of the raw material in any section of the stack of wood should not exceed 20°C.

Also, for example, an installation for soil disinfection in greenhouses is a small microwave device that travels from one greenhouse to another and is structurally similar to the installation described above, only instead of wooden planks a stack of boxes with soil is placed in it.

So, for all types of installations, it is important that the generators of microwave radiation inside the chambers are distributed inside them, this allows you to heat the materials evenly. This is essential for positions such as:

Obtaining new heat-insulating building materials by the swelling method (based on liquid glass with fillers, cement-bonded expanded polystyrene granules, etc.);

Heating and drying of raw materials (bales of tobacco before fermentation and cutting, food products and others).

Structurally, these devices must be designed so that the heating of the raw material inside the chambers occurs evenly. In addition, it is desirable to make the internal cavities of these units spacious enough so that large production volumes of raw materials can be processed per unit of time.