Protection focus For a long time, people have been trying to find effective means to prevent moisture, mildew and corrosion, so as to solve the problem of safe storage of items. Focusing on controlling the environmental moisture and controlling the relative humidity of the environment at about 50%, the storage safety of most items can be guaranteed. To achieve this goal, a variety of drying methods have been used. There are three main traditional methods, namely high temperature dehumidifier, low temperature dehumidifier and moisture absorbent dehumidification.

The way to dehumidify and prevent moisture:

  1. High-temperature dehumidification method: High-temperature dehumidification mainly uses heating to dehumidify, such as various electric heating and far-infrared drying ovens, ovens, etc. Due to the high working temperature, it will destroy items composed of organic materials, and at the same time, it will also have a heat treatment effect on metal materials, change the properties of the metal, and cause damage. And long-term continuous heating is also unrealistic. Therefore, as a long-term safe storage item, the method of high temperature dehumidification is not used.
  2.  Low-temperature dehumidification method: The low-temperature dehumidification mainly uses refrigeration refrigeration and dehumidification. Its working principle is to reduce the surface temperature of the condenser through the refrigeration device, so that the moisture in the air condenses on the condenser, and then drips out to remove. In this way, the moisture in the air of the sealed space is discharged to reduce the humidity, which is a low temperature dehumidification. Freezing dehumidification is currently the most effective, safe and economical dehumidification method.
  3. Vacuum drying method: the air in the drying cabinet is evacuated to achieve the purpose of removing moisture . It consists of a box and a vacuum pump. Due to the vacuuming, the requirements for the box body and box door to withstand atmospheric pressure and sealing are very high. Compared with the external size of the box body, the effective use space inside is small. And it can only be realized in a small cabinet, which requires decompression during use, which is inconvenient and expensive to purchase. The scope of application is small.
  4. Dehumidification method of hygroscopic agent: Generally, silica gel is placed in a sealed container for dehumidification. The disadvantage is that when the moisture absorbent is saturated, it needs to be replaced or manually dried and regenerated, and the long-term maintenance work is quite complicated; more importantly, because the saturation time of the moisture absorbent is not easy to accurately predict, the humidity in the container cannot be depended on. The degree of discoloration of the paradoxical silica gel can be accurately known, so that the moisture absorbent cannot be properly replaced in time.

Second, the occurrence and harm of mold:

  1. The occurrence of molds There are many kinds of molds, including Ascomycetes, Phytomycetes, Incomplete fungi, etc. in the fungal phylum. Among them, there are more than 40,000 species that have an invasive effect on industrial materials. Mold transmission mainly relies on spores, which are in the form of tiny powders and are not easily visible to the naked eye. The spores are ejected from the mold and, due to their small size and light weight, float around with the movement of air currents and dust and the movement of people and objects. Once it encounters a suitable environment for development, it can be grown and reproduced, and it can be passed down from generation to generation, which is often said to grow mold.
  2. Conditions for mold growth 1), humidity: mold can grow when the relative humidity of the environment is greater than 60%. When it is greater than RH 65%, the growth is accelerated, and when the humidity reaches RH80-95%, it is a high-incidence environment for mold. 2), temperature: mold mycelium can grow at an ambient temperature above 8 degrees, and the growth is accelerated when it is above 12 degrees. When the temperature is above 10 degrees and the humidity is above 60%, the mold can cause harm to items. When the temperature is 20-35 degrees and the humidity is 75-95%, the mold can grow explosively.
  3. Occurrence and harm of metal oxidative corrosion The process of oxidative corrosion of metal is the process of electrochemical reaction of metal caused by moisture and oxygen in the air. Scientific research has proved that the critical value of air relative humidity for metal oxidative corrosion is 70% for steel, 60% for copper, 76% for aluminum, 63% for iron, and 60% for zinc. When metals are stored in an environment above this critical value, the rate of oxidative corrosion will continue to accelerate with the increase of the relative humidity of the air.