Work flow of operation: 1, vacuum: vacuum chamber closed cover, vacuum pump work, vacuum chamber began to pumping vacuum, vacuum in the bag at the same time, the vacuum gauge pointer rises, reaching the rated vacuum (controlled by the time relay ISJ) vacuum pump to stop working, vacuum stop. At the same time of vacuum work, two-position three-way solenoid valve IDT work, heat sealing gas chamber vacuum, heat pressing frame keep in place. 2, heat sealing: IDT break, the outside atmosphere through its upper air inlet into the heat sealing gas chamber, the use of the vacuum chamber with the pressure difference between the heat sealing gas chamber, heat sealing gas chamber inflatable expansion, so that the heat press frame down, press the bag mouth; at the same time, the heat sealing transformer work, start sealing; at the same time, the time relay 2SJ work, a few seconds after the action, the end of heat sealing. 3, back to the air: two-position two-way solenoid valve 2DT pass, the atmosphere into the vacuum chamber, the vacuum gauge pointer back to zero, the hot press frame rely on reset spring reset, the vacuum chamber open cover.Mechanism of action: The main function of vacuum packaging is deoxygenation, to prevent food spoilage, the principle is relatively simple, is to remove the oxygen and food cells in the bag, so that microorganisms lose their living environment. Experiments show that: when the oxygen concentration in the bag is less than 1%, the growth and reproduction rate of microorganisms will drop sharply, when the oxygen concentration is less than 0.5%, most microorganisms will be inhibited and stop reproducing. (Note: vacuum packaging can not inhibit the reproduction of anaerobic bacteria and enzyme reaction caused by food deterioration and discoloration, so it needs to be combined with other auxiliary methods, such as refrigeration, quick-freezing, dehydration, high-temperature sterilization, irradiation sterilization, microwave sterilization, salt pickling, etc.