What is a Microwave Oven?

A microwave oven / microwave, as the name suggests, is a modern cooking stove that uses microwave to heat food.

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Microwave oven / microwave, as the name implies, is a modern cooking method that uses microwave to heat food

The national standard for energy efficiency of the microwave oven industry, "GB24849-2010 Limit Values and Energy Efficiency Ratings for Microwave Ovens for Household and Similar Uses," was officially released and officially implemented on December 1, 2010.

The implementation of microwave oven energy efficiency standards will promote the industry's product upgrades and technology upgrades, which is conducive to the overall value of the industry and further enhances the competitiveness of domestic enterprises in the international market. For the society, it is not only conducive to consumers to save costs but also to energy conservation Therefore, the entire industry is taking effective measures to respond positively.

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A microwave oven is a cooking appliance that uses food to absorb microwave energy in a microwave field to heat itself. The microwave generated by the microwave generator in the microwave oven establishes a microwave electric field in the microwave cavity, and certain measures are taken to make this microwave electric field as evenly distributed as possible in the oven cavity. The food is placed in the microwave electric field and the cooking time is controlled by the control center. And microwave electric field strength to perform various cooking processes.

Generally speaking, microwave is a kind of high-frequency electromagnetic wave. It does not generate heat by itself. There are microwaves everywhere in the universe and nature, but there are microwaves in nature. Because they are not concentrated, they cannot heat food. Microwave ovens use their internal magnetrons to convert electrical energy into microwaves.

Microwave refers to electromagnetic waves with a frequency ranging from 300MHz to 3000GHz, and its corresponding wavelength ranges from 1m to 0.1mm. This electromagnetic spectrum includes decimeter waves (frequency from 300MHz to 3GHz), centimeter waves (frequency from 3GHz to 30GHz), millimeter waves (frequency from 30GHz to 300GHz) and sub-millimeter wave (frequency from 300GHz to 3000GHz) four bands.

From the point of view of electron optics and physics, the electromagnetic spectrum of microwave has the following important characteristics that are different from other wavebands:

1.Light-like and sound-like

The wavelength of the microwave is very short, which is shorter than the average objects on the earth such as airplanes,

1. Wave heat effect. The changing speed of the electromagnetic field in the microwave oven cavity is as high as 2.45 billion times per second (microwave frequency is 2450 MHz). It acts on polar molecules such as water molecules in food, causing it to swing back and forth 2.45 billion times / second. High friction is generated by the frictional movement of the wheel, thereby achieving the purpose of heating.

2. Biological effects. Because the ability of the microbial cell fluid to absorb microwaves is superior to other surrounding media, the cells in the microwave electromagnetic field will rapidly rupture and cause bacterial cell death.

1. Reflective. The microwave will be reflected back when it encounters the metal. Therefore, the inner wall is made of specially treated steel plate. According to the reflection effect caused by the inner wall of the microwave oven, the microwave penetrates the food back and forth, enhancing the thermal efficiency. However, metal containers must not be used in the furnace, otherwise it will affect the heating time and even cause sparks in the furnace.

2. Penetrability. Microwave has the penetrating effect on general ceramics, glass, heat-resistant plastic, wood, bamboo, etc., so it is the best utensil for microwave cooking.

3. Absorptivity. Various types of food can absorb microwaves, causing the molecules in the food to oscillate and friction to generate heat energy. However, its degree of penetration into various foods varies depending on factors such as its quality and quantity, thickness, etc.

"Microwave Carcinogenic" Perspective

Because microwave is a

With the progress of science and technology, electronic technology, sensor technology and material technology have been greatly developed in recent years. In order to meet the requirements of microwave oven consumers, domestic and foreign microwave oven R & D institutions and production plants have introduced a variety of advanced and modern microwave oven products and introduced a series of new and advanced microwave oven products. These new microwave oven products reflect the development trend of microwave oven technology and are mainly manifested in the following aspects:

The microwave oven consists of seven parts:

Magnetron: It is the "heart" of a microwave oven. It generates and emits microwaves (DC power is converted to microwave oscillation output). It is actually a vacuum tube (metal tube).

Power transformer: It is the component that supplies voltage to the magnetron.

Furnace cavity: also called a resonance cavity, it is a place for cooking food, made of metal plates coated with non-magnetic materials. There are ventilation holes on the left and top of the cavity. The microwave input into the cavity through the waveguide is reflected back and forth in the cavity wall, and each propagation passes through and through the food. When designing a microwave oven, the side length of the cavity is usually a multiple of 1/2 the wavelength of the guided wave, so that when the food is heated, the cavity can maintain resonance and the resonance range is appropriately widened.

Waveguide: The microwave power generated by the magnetron is transmitted to the cavity to heat the food.

Rotary table: The rotary table is installed at the bottom of the furnace cavity, and has a certain height from the bottom of the furnace. It is driven by a small motor with a speed of 5-6 rpm.

Furnace door: The function of the stove door is to facilitate the access to food and observe the situation during cooking. The stove door is the front wall of the cavity.

Time power controller: Choose different power to cook or thaw different foods.

First, the microwave oven is not easy to color the food surface. You can apply the seasoning to the food surface before cooking to make it dark brown.

Second, the food heated in the microwave oven is extremely hot, and it is easy to evaporate moisture. When cooking, it should be covered with heat-resistant plastic wrap or temperature-resistant glass cover to keep moisture. Tips of chicken wings, chicken breasts or fish heads, fish tails or corners of cakes are easy to overcook. Covering with aluminum foil for microwave ovens can achieve uniform cooking.

3. At the end of heating, leave the food for a period of time or add some condiments to some food (for example, after cooking poultry meat, you can pour in emulsified oil or sauce, and sprinkle some paprika, bread crumbs, etc.). To achieve a satisfactory effect that can not be achieved by heating.

Fourth, the food should be arranged evenly, not in a pile, so that the food can evenly generate heat. Small pieces of food ripen faster than large pieces. It is best to cut the food into smaller pieces less than 5 cm. The more regular the shape of the food, the more uniform the microwave heating. Generally, the food should be cut into pieces or pieces of appropriate size and shape.

5. If the food has a hard skin, it must be peeled off before cooking.

6. The higher the temperature of the food, the shorter the cooking time; the heating time in summer is shorter than that in winter. Cooking thick, dense food takes longer to heat than porous food. Foods with high water content generally absorb more microwaves, and cooking time is shorter than those with lower water content.

7. When cooking food in a microwave oven, it is better to undercook than to overcook. Microwave re-cooking will not affect the color and aroma of the dishes.

8. When cooking in a microwave oven, the amount of salt should be reduced as much as possible, so that cooked food can be prevented from being cooked outside and endogenous. ^[10-11]

Heating according to the characteristics of the food

Early food temperature. The higher the temperature of the food itself, the shorter the cooking time; the heating time in summer is shorter than in winter.

Adjustment of food amount. The amount of food is proportional to the heating time. The more food, the longer the heating time.

Food density and water content.

Kind reminder: Please ask professional maintenance personnel for operation.

When the microwave oven is in use,

Microwave oven self repair

Microwave oven maintenance and replacement tips

In daily use of the microwave oven, pay attention to cleaning the mica sheet from time to time, keep it clean and dry. The mica sheet cannot be cleaned due to serious pollution or the black spots that have been punctured must be replaced in time. Users with strong hands can operate it by themselves The key component of the microwave oven, the "magnetron", is not damaged.

The steps to replace the mica sheet are as follows:

1. Prepare new mica tablets. Microwave ovens can be bought on a certain Bao business platform and the price is very low.

2. Remove the old mica sheet.

Removal method of mica sheet with different fixing methods: The card slot is the easiest to remove. No tools are needed, just be careful to pull it from the bottom up. When the inner cavity protruding part is slightly forced to bend the mica sheet, then continue to push up. It can be removed; if it is locked by a plastic plug, it can be easily removed by prying the plug with a screwdriver.

3. Clean the microwave emission window with a paper towel or rag.

4. Use scissors to cut a prepared new mica sheet (the new mica sheet is larger).

5. Install the cut new mica sheet in the reverse order of removal. If it is fixed with a plug, press it firmly against the hole in the microwave emission window.

Hint: Mica flakes are brittle in texture and can easily crack if bent excessively.

If the mica sheet is burned and ignited after the microwave oven is powered on, this situation is often a malfunction of the magnetron and needs to be repaired by a professional.

New Microwave Oven Mica Tablets

Professional microwave oven repair

First, before disassembling and repairing, the safety-related parts and components must be inspected first, mainly to see whether the furnace door is tightly closed, the door gap is too large, the observation window is cracked, and the Whether the solder joints are de-soldered, whether the furnace door seal is missing, and whether the unevenness is uneven. This is mainly to check for the possibility of excessive microwave leakage. If a problem is found, it should be repaired first; if it cannot be repaired temporarily due to missing parts or other reasons, you can repair other faults in the machine first, but do not force use after repairing other faults, let alone the use of the user, after removing the potential safety hazard Before delivery.

Second, if you need to check the circuit inside the machine, you should usually disassemble the microwave oven after power off. After disassembling, first use a plastic insulation handle screwdriver to short-circuit the two ends of the high-voltage capacitor to avoid accidental electric shock during maintenance. This is because after the microwave oven is powered off, there may still be a high voltage on the high-voltage capacitors, especially the stove shortly after the power is turned off. Do not think that it is safe after the power is turned off.

Third, in addition to measuring the 220V mains voltage and other inspections, if there is no certainty, you should try not to conduct a live power inspection. If power-on inspection is really needed, the high-voltage circuit must be disconnected to prevent the magnetron from working, and then turn on the inspection to ensure personal safety. As for the inspection of the magnetron and its power supply circuit, unless you have the necessary professional maintenance equipment knowledge and experience, you should use a power failure inspection method to ensure safety. Practice has shown that, as long as you master the relevant skills, power failure inspection is not much worse than power-on inspection, and the speed of judging some faults is even better than power-on inspection.

Fourth, when repairing or inspecting or replacing parts during maintenance, remember the original positions of the removed parts one by one, especially the parts of the safety mechanism and high-voltage circuits. Good to prevent loss and cause unnecessary trouble; when reassembling, it should be accurately reset one by one, and tighten each fastening screw and other fasteners. Do not install it incorrectly, or omit small parts that are easily overlooked such as gaskets. If you need to replace parts, please pay attention to the original accessories. If not, replace them with replacement parts of similar characteristics and installation dimensions.

Fifth, after the maintenance is completed, after all the components are installed, the furnace door should be checked again for flexible opening and closing. At the same time, pay attention to check the door gap, door mat and observation window for abnormal conditions, as well as various adjustment buttons and switches. Check whether the parts are normal. Do not start using them until you are sure there are no problems. ^[12-13]