What is the function of installing an air barrier in a fruit and vegetable vending machine?

What is the function of installing an air barrier in a fruit and vegetable vending machine? Many people will wonder why the fruit and vegetable vending machine is equipped with an air barrier. The following author will come to find out with you. Because the temperature on both sides of the unmanned vending machine enclosure structure (or the inside and outside sides of the unmanned vending machine) is different, along with the transfer of heat, the movement of wet air flow occurs. This movement of moisture is called water vapor penetration. It is difficult to block the penetration of water vapor. It is even more difficult than blocking the heat flow. The temperature difference between the two sides of the enclosure will cause the partial pressure difference of water vapor, thus forming the power of water vapor penetration. For example, the outside (high temperature side) of the unmanned vending machine is 30°C, the partial pressure of water vapor at a relative humidity of 60% is 19.09mm Hg, and the low temperature side is at 0°C, even when the relative humidity is 100%, the water vapor The pressure is only 4.58mm pump column. In this way, the partial pressure of water vapor on both sides of the enclosure structure is (19.09mm Hg-4.58mm Hg). 14.51mm mercury column, which is a considerable driving force than an ordinary fan with a pressure head of 30-60mm water column because of this driving force. The water vapor can be forced through the cracks of the tiny pores of the enclosure structure into the unmanned vending machine. For low-temperature unmanned vending machines, this means that the wet air pressure enters the enclosure structure and the insulation layer. It has extremely adverse effects on the heat preservation of the unmanned vending machine. Especially for fruit and vegetable vending machines with controlled atmosphere, it is especially important, because in addition to water vapor entering the enclosure structure is not conducive to heat preservation, it will also cause changes in the gas in the unmanned vending machine, which is not conducive to the storage of fruits and vegetables. Driven by the partial pressure difference of water vapor, the water vapor outside the unmanned vending machine will penetrate into the unmanned vending machine. When water vapor penetrates into the air barrier of the enclosure structure, when the cold air reaches the dew point or freezing point (especially in low-temperature unmanned vending machines), the water vapor will condense in the voids and gaps of the insulation material. Water droplets or ice crystals will make the insulation material damp and reduce the insulation performance. Because the thermal conductivity of ice is 2.0W/(M?K), which is about 100 times larger than the thermal conductivity of polyurethane of 0.02W/(M?K), it will damage the thermal insulation layer in severe cases. Therefore, in order to ensure that the thermal insulation material maintains good thermal insulation performance, prolongs the service life, and maintains the normal use of the unmanned vending machine, it is very important to provide a moisture-proof and gas barrier layer on the surface of the thermal insulation layer. If you need to know more about fruit and vegetable vending machines, please click to enter our company's official website. Previous post: What are the advantages of fresh vending cabinets?