The difference between stretch film packaging machine and microwave dryer
The difference between stretch film packaging machine and microwave dryer. Vacuum packing machine occupies a very important position in the field of food packaging. Microwave refers to the wave length in 0.001~1m frequency is between 3G~30GHz electromagnetic wave. With the continuous development of science and technology, microwave technology is rapidly applied in the fields of communication, broadcasting, television and chemical industry, providing great convenience for human production and life. Microwave application in the food industry began in the early 1960s, although only a few decades, due to the advantages of microwave baking, such as fast, sanitary, convenient, has been accepted by a considerable number of manufacturers and home users, and opened up a new application field, showing a bright application prospects. Automatic vacuum packing machine plays a certain role in the automatic equipment.
The difference between stretch film packaging machine and microwave dryer. Microwave drying mainly USES the thermal effect of microwave. Microwave itself does not generate heat, it is a kind of high-frequency electromagnetic wave. The direction of the alternating electric field formed by microwave changes at a high speed, which makes the polar molecules in the microwave field also oscillate at a high speed. If the food rich in water is in the microwave field of 2450MHz, the oscillating frequency of water molecules with great polarity will reach 0.408 billion times /min. The rapid movement of molecules will intensify the collision and friction between water molecules, generating a large amount of heat, so that food can be heated and baked. As microwave is an electromagnetic wave, it will reflect, refract, absorb and penetrate in the actual propagation process, so the microwave effect of dry food in microwave oven is the superposition of microwaves from all directions. The price of vacuum packing machine is mainly reflected in the configuration of vacuum pump.
The difference between stretch film packaging machine and microwave dryer. The unit of frequency used in microwave is megahertz (MHz), which is currently used in industry and scientific research. Only 915MHz(wavelength 0.328m) and 2450MHz(wavelength 0.1225m) are widely used. In the higher two bands (, K), there is no high-power equipment, which is because the power, efficiency and cost of microwave tube have not reached the industrial use requirements. The development of packaging machinery brings people new packaging experience.
The difference between stretch film packaging machine and microwave dryer. The materials commonly used in microwave can be divided into conductor, insulator and magnetic compound. In the process of transmission, microwave will encounter different materials and produce reflection, absorption and penetration phenomenon. This situation completely depends on several characteristics of the material itself, such as dielectric constant, dielectric loss coefficient, specific heat capacity, shape and water content.
Differences between stretch film packaging machine and microwave dryer (1) conductors such as copper, silver, aluminum and other metals can reflect microwave, so use this property to spread and reflect microwave. The waveguide, a rectangular or circular metal tube, is commonly used in microwave systems and is usually made of aluminum or brass.
The difference between stretch film packaging machine and microwave dryer (2) insulation can penetrate and partially reflect microwave, microwave absorption function is small, using its characteristics, in the microwave system, according to different conditions, the use of glass, ceramic mica, ptfe, polypropylene and other insulators.
Differences between stretch film packaging machine and microwave dryer (3) dielectric properties between metal and insulator. For microwave, medium has the properties of absorption, penetration and reflection. In microwave heating and drying operations, the materials treated are usually the media that absorb microwave to different degrees. Such materials are called consumable media, especially the materials containing water and fat, which absorb microwave and convert it into heat to different degrees.
Differences between stretch film packers and microwave dryers (4) magnetic compounds behave much like dielectric materials and also reflect, absorb and penetrate microwaves. Because microwave has the electric field and magnetic field that can affect the dielectric material and magnetic material, it is also the material that can be easily treated by microwave.