Vacuum packaging machine work process:
1. Vacuum: The vacuum chamber is closed, the vacuum pump works, the vacuum chamber starts to vacuum, the vacuum inside the packaging bag, the vacuum gauge pointer rises, reaches the rated vacuum (controlled by the time relay ISJ), the vacuum pump stops working, and the vacuum stops. While working under vacuum, the two-position three-way solenoid valve IDT works, heat seals the chamber vacuum, and the hot press holder remains in place.
2. Heat sealing: IDT is broken, the outside atmosphere enters the heat sealing chamber through the upper air inlet hole, and the pressure difference between the vacuum chamber and the heat sealing chamber is utilized, and the heat sealing chamber is inflated and expanded to be placed under the hot pressing frame. Move, press the bag mouth; at the same time heat seal the transformer work, start sealing; at the same time, the time relay 2SJ works, after a few seconds, the heat seal is over.
3, return air: 2/2-way solenoid valve 2DT pass, the atmosphere enters the vacuum chamber, the vacuum gauge pointer returns to zero, the hot press frame is reset by the return spring, and the vacuum chamber is opened.
4. Circulation: Move the above vacuum chamber to another vacuum chamber, that is, enter the next working process, and the left and right chambers work alternately, and the cycle is repeated.
The main function of the vacuum packaging machine is to remove oxygen, which is beneficial to prevent food spoilage. The principle is also relatively simple, because the deterioration of food mold is mainly caused by the activity of microorganisms, and the survival of most microorganisms (such as mold and yeast) is needed. Oxygen, and vacuum packaging is the use of this principle, the oxygen in the packaging and food cells are removed, so that the microbes lose their living environment. The experiment proves that when the oxygen concentration in the package is ≤1%, the growth and reproduction speed of microorganisms will drop sharply. When the oxygen concentration is ≤0.5%, most microorganisms will be inhibited and stop breeding. (Note: Vacuum packaging can not inhibit the deterioration and discoloration of food caused by anaerobic bacteria reproduction and enzyme reaction, so it must be combined with other auxiliary methods, such as refrigeration, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt Pickled, etc.)
In addition to inhibiting the growth and reproduction of microorganisms, vacuum deoxygenation is another important function to prevent oxidation of foods. Because oils and fats contain a large amount of unsaturated fatty acids, they are oxidized by the action of oxygen, which makes foods taste and deteriorate. In addition, oxidation also makes Loss of vitamins A and C, unstable substances in food pigments are affected by oxygen, which makes the color darker. Therefore, oxygen scavenging can effectively prevent food from spoiling.
In addition to the deoxidation and quality assurance functions of vacuum packaging, vacuum inflated packaging mainly has the functions of anti-pressure, gas barrier and preservation, which can effectively maintain the original color, fragrance, taste, shape and nutrition of food for a long time. value.
In addition, there are many foods that are not suitable for vacuum packaging and must be vacuum-filled. Such as crispy and fragile food, easy to agglomerate food, easy to deform and oily food, food with sharp edges or high hardness will pierce the bag. After the food is vacuum-insulated, the inflation pressure in the packaging bag is stronger than the atmospheric pressure outside the packaging bag, which can effectively prevent the food from being crushed and deformed without affecting the appearance and printing decoration of the packaging bag.
The vacuum inflated package is filled with a single gas such as nitrogen, carbon dioxide or oxygen or a mixed gas of two or three gases after being vacuumed. The nitrogen gas is an inert gas, which acts as a filling to maintain a positive pressure inside the bag to prevent the air outside the bag from entering the bag, thereby protecting the food. Its carbon dioxide is soluble in various types of fat or water, and it is classified into weakly acidic carbonic acid, and has the activity of inhibiting microorganisms such as mold and spoilage bacteria. Its oxygen inhibits the growth and reproduction of anaerobic bacteria, keeps the freshness and color of fruits and vegetables, and high-concentration oxygen keeps fresh meats bright red.