Free standing microwave
The “birthday” of the microwave oven is the 8th day of the 10th month of the distant 1945. On this day, inventor Percy Spencer was awarded a patent for an invention.
An accident helped the American scientist. He felt the softening of the candy bar in his pocket as he stood near the military radar wave transmitter. Then there were experiments with corn and an egg – in the first case, popcorn turned out, in the second – an explosion.
And so a new invention arose – the microwave oven. In modern models, ultra-high frequency (UHF) waves heat up and cook food.
How the microwave works
Already in 1947, the first 340-kilogram human-height microwave ovens appeared in the military kitchens of the United States. Since 1962, microwave ovens for domestic use have gone into the series, but already by the Japanese company Sharp. She was the first to run a rotating platform inside the oven in 1966, and since 1979 microprocessor control has been used in the ovens.
Many years of research and development of microwave ovens have made it possible to minimize the size, myths about the harmfulness of microwave radiation have been debunked. Check how it works – put a mobile phone in a non-working oven, close the door and dial its number. If you can’t get through, the device is well shielded and does not transmit radio waves, which means it’s safe.
The microwave oven is a metal (rectangular or hemisphere) parallelepiped, with a magnetron, a power system and a control unit.
The 220 volt power supply is converted in front of the magnetron to a value of 2000 volts and provides energy for the formation of electromagnetic waves with a frequency of 2450 hertz.
Waves of this frequency cause water molecules from food to move and interact with each other. As a result of this process, heat is released and food is heated. Heating occurs from the upper layers to the lower to the depth of the radiation – up to 25 mm. The only exceptions are bakery products, the heating of which starts from the inside.
Type and configuration
By type, microwave ovens are divided into those located separately and built into kitchen furniture. In their appearance and parameters, they differ little. The advantage of built-in models is saving space in the kitchen. Minus – the price is higher than that of other types of devices, due to the need for increased thermal insulation of the case.
A free-standing microwave oven has a lower level of protection from the heat generated during heating, which is noted in the manufacturer’s instructions by the distances that are observed between the device and furniture or other household appliances. The cost of such microwaves is less than built-in ones. And they are equipped with a door that opens down or to the side.
Free-standing microwave ovens are a popular and widespread product due to their price range and simple manufacturing. Such a product will find a place in any kitchen, and for the built-in option, you will have to spend money on replacing kitchen furniture.
Types of freestanding microwaves
The oven quickly defrosts or reheats food and products. She does not perform other tasks. Dishes in this type of microwave oven are cooked without baking and without the formation of a crust on the products.
It is in demand for heating food in the dining rooms of offices. These devices are economical in terms of electricity used, their prices are affordable. The standard volume for the species under study is up to twenty liters.
microwave oven with grill
Microwave for heating food and baking food. The grill performs heating with a heating element or thanks to a quartz heating element. In the first position, heat transfer occurs from a tubular heating element, which is made movable for convenience.
A furnace with a quartz heating element is more compact, but the heating technology provides for heat transfer in one direction – in the plane in which the quartz lamp is fixed.
Microwave with convection and grill
It is able to cook a dish using complex technology, and in terms of functionality it is equivalent to ovens.
Convective heat exchange occurs due to the built-in fan, which mixes hot air in all areas inside the device. Due to the same temperature in any zone, the dish is heated evenly and comprehensively, identical to the oven or skewer.
Functions and characteristics of microwaves
When choosing a microwave oven, pay attention to the material of the inner coating of the chamber – it affects the life of the model and the convenience of cleaning the chamber.
Heat resistant enamel
Common coverage option. Convenient surface – when washing, it is easy to remove carbon deposits and food residues on the walls of the chamber, which will not require much effort or time.
This coating is resistant to temperature fluctuations, but does not withstand frequent high thermal operating conditions. Because of this, the service life of the device is limited to 5-7 years.
As a disadvantage, the ease of damage to the surface of the enamel during careless cleaning is noted. From exposure to high temperature, in places of scratches, cracks form on the surface, which reduces the operational period.
The material is strong and relatively cheap, which guarantees a long period of operation. The advantages of steel are in resistance to frequent changes in thermal conditions and prolonged high temperatures, and it is impossible to damage such a material.
The negative point is that deposits of burnt drops of fat easily adhere to such a coating. It is difficult to remove such pollution. This means that the chamber inside the oven will require constant attention and care.
But you can protect yourself from this with the help of glass or polystyrene caps placed above the dish and preventing drops of fat from splashing.
The latest development of the scientific community, which includes the advantages of the two previous surfaces. It is not subject to scratches, fat deposits do not burn on it, it is quickly and easily cleaned, which extends the service life.
The only negative factor currently remains the high cost of such models. With the same functionality, the price, compared to other models, will be twice as high.
Today, by no means cheap models have an antibacterial coating. On the surface of such a model, the amount and rate of reproduction of the microbial environment is reduced, which is confirmed by laboratory studies.
When choosing a microwave oven, one should not forget that: the larger its chamber, the larger the size of the dish cooked in it.
20 or less liters
Small models, equipped with functions only for defrosting and heating food. The advantage of such microwave ovens is their compact size and low cost. But a large plate will not enter the microwave of this volume.
In this device, it will turn out to warm up and cook dishes in several modes. This is convenient for families up to 3-4 people, since this volume allows you to simultaneously heat up two standard servings of food.
These microwave ovens have a grill function. In smaller microwaves, a grill is also found, but it will not be possible to use all its capabilities.
These are the largest models in which meat is perfectly cooked and pies are baked. Devices of this volume belong to the premium class and are equipped with the maximum list of functions.
Pay special attention to the power of the device when inspecting the microwave oven you like. The larger the parameter you choose, the better and more efficiently the dish will be cooked.
Manufacturers produce models with power from 450 watts to 1680 watts. This value should be comparable to the volume of the device: the larger the chamber, the greater the power demand.
Up to 70% of devices on the market are sold with a power of 800-1000 watts. Less power should not be taken into account, unless the buyer is aimed at purchasing a microwave with a minimum volume.
- Electronic touch control – allows you to program the preparation of dishes. In such devices, dirt does not clog between the regulators. The buttons turn on the set cooking mode, for example “grilled chicken” or “quick defrosting”. There may also be functions for entering individual cooking parameters into the device’s memory.
- Mechanical control – made in the form of regulators. They are easy to operate, but such models are usually produced with a minimum of features. In addition, dust settles on the switch heads, which reduces the ease of cleaning.
- Clock control – occurs both with buttons and regulators. The buttons select the cooking mode, and the switches set the time and power.
Not the cheapest models of microwave ovens are equipped with modes that facilitate the work of housewives:
- automatic temperature maintenance – maintains the set cooking temperature of the dish, turning the magnetron on or off if necessary;
- automatic cooking – memory for cooking certain dishes;
- auto-defrost/auto-reheat – automatic determination by the type of product of the operating time of the device;
- programming recipes into memory – storing your own cooking settings in memory and applying them after entering the parameters set manually (for example, type of dish and weight of products);
- accelerated defrosting / warming up – quickly defrost / warms up food, with small portions;
- start delay function – turns on the heating of the food previously installed in the chamber at the appointed time.
The cost of stoves, leaders in quality among these devices, varies in functionality, but the models are of the same quality from junior to senior.
When purchasing a cheap and simple device, be sure that it will be reliable and made of quality materials.
Manufacturers provide decent after-sales service, which is important for consumers who use household appliances on a daily basis.
The premium group often has an elegant and comfortable design, high-quality bioceramic coating and electronic control. This significantly increases the cost of models.
Brand awareness also inflates the price. In the case of comparing products that are identical in size and functionality, the price will be 15-20 percent higher.
Modern brands of microwave ovens are equipped with a display, camera lighting, push-button opening, a spit, a steam sensor and a cooking container, a child lock and other useful features.
The problem of the lack of heating of products holds the palm among the malfunctions. In this case, the indication means show the norm, if there is a grill in the chamber, it works. Sometimes it can spontaneously turn off.
The causes of the malfunction may be as follows:
- breakdown of a high-frequency discharge from the magnetron to the body;
- damage to the power supply circuit, parts of the voltage converter and magnetron;
- blown high voltage fuse.
To eliminate the first reason, the condition of the mica plate that closes the opening to the magnetron is checked. If the plate is dirty or damaged, it must be cleaned or replaced.
Then a general cleaning of the chamber from the inside is performed. It is recommended to clean with ethanol or vodka. If the paint under the mica is damaged, the problem area is cleaned and covered with heat-resistant special paint. In extreme cases, it is simply cleaned to the metal.
Food residues collected during the operation of the microwave form a conductive layer that reduces the power of electromagnetic waves passing through the mica plate. At best, food takes longer to heat up.
At worst, due to the contact of the formed conductive layer with the metal of the device case, a high-frequency discharge occurs between the magnetron antenna and the furnace body. In this case, there is a simultaneous release of a large amount of heat. It is enough to destroy the mica plate and the cap of the magnetron antenna, which means their automatic replacement.
Other causes of microwave malfunctions require additional diagnostics, so all manufacturers recommend contacting service centers.
Remember: open electromagnetic radiation is dangerous for living organisms, do not disassemble the device yourself.
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