Abstract: Controlling and regulating the humidity of the warehouse is a very important routine work in the maintenance of goods, and an important measure to maintain the quality of goods. In the process of commodity storage, according to the characteristics of the characteristics of goods and quality changes, reasonable storage arrangements, scientific use of sealing, ventilation, dehumidifiers and other methods to properly control and adjust the humidity of the warehouse to ensure the safety of goods.

First let's understand: absolute humidity, saturated humidity, relative humidity and dew point.

Absolute humidity is the amount of water vapor actually contained in a unit volume of air, expressed as e. A method of expressing absolute humidity is generally employed, that is, expressed in units of grams per square meter (g/m2) or millibars (mb).
Saturated humidity is the maximum amount of water vapor that can be contained per cubic meter of air at a certain temperature, expressed in E, expressed in grams per square meter or millibars, millimeters of mercury.

Relative humidity is the degree to which the actual amount of water vapor in the air is saturated, or the percentage of absolute humidity and saturated humidity of the air at the same temperature. Expressed by γ, the formula is: relative humidity = absolute humidity / saturated humidity × 100%

The dew point is air containing a certain amount of water vapor. When the temperature drops to a certain level, the water vapor in the air is saturated and begins to liquefy into water. We call this phenomenon condensation, and the temperature at which water vapor begins to liquefy into water is called the dew point temperature, or the dew point.

(1) Seal

Sealing is to use materials with better heat insulation and moisture resistance to seal the goods as tightly as possible to prevent and reduce the influence of external temperature and humidity on the goods, so as to achieve safe storage. Sealing measures are the basis for warehouse temperature and humidity management. Sealing the warehouse can keep the temperature inside the warehouse relatively stable. If it can be reasonably appropriate according to the characteristics of the product, it can receive various effects such as moisture, mildew, heat, frost, rust and anti-aging.

At present, the commonly used sealing materials are as follows: moisture-proof paper, linoleum paper, plastic film, rice husk, fiberboard, lush, sawdust, hay, river sand and so on.

There are many types of seals, mainly including the whole warehouse, the whole room, the whole raft, the whole cabinet, and the whole seal.

In order to ensure the quality and safety of the goods during the sealing period, the following must be noted:

Quality requirements for sealed goods

Before sealing, it is necessary to carefully check whether the quality and moisture content of the product are normal. If the moisture content of the product is too high, mildew, rust, insects or other deterioration, it must undergo dehumidification, mold removal, rust removal, and extinction. The insects and other treatments can restore the quality of the product to normal before sealing.

Sealing time selection

The sealing time is determined according to the nature of the product. Products that are afraid of moisture and mildew should be sealed before the arrival of the rainy season; products that are afraid of heat and fusibility should be sealed in a cooler season; those that are afraid of frozen goods should be sealed when the temperature is high; Seal at a higher temperature and before the drying period.

Sealed commodity inspection

After the product is sealed, it should be inspected regularly. Because the seal is only a relative seal, the impact of the climate on the commodity cannot be completely isolated. During the inspection, if the goods and packaging are found to be abnormal, or the temperature and humidity are not suitable, measures should be taken to remedy in time to protect the quality of the goods.

(2) ventilation

Ventilation is based on the natural flow of air, purposefully to make the air inside and outside the warehouse exchange, in order to achieve the purpose of regulating the temperature and humidity of the air inside the warehouse. The use of ventilation to adjust the temperature and humidity in the library is an easy and effective method. However, certain conditions are required for ventilation to receive the expected results. Otherwise, it may be counterproductive.

Warehouse ventilation should be based on the nature of the goods and their different requirements for temperature and humidity, combined with the temperature and humidity comparison inside and outside the library, and refer to the wind, wind direction, etc., reasonable choice of ventilation timing for ventilation, to maintain the safety of commodity quality.

Ventilation cooling

Some products have stricter temperature requirements, while air humidity requirements are less stringent. Such as volatile hydrogen peroxide, ammonia and other chemical products. Such hot-spot products can be ventilated during the summer as long as the temperature outside the warehouse is lower than the inside of the warehouse.

Ventilation

When the temperature outside the library is higher than the temperature inside the library, the ventilation method can be used to raise the temperature. Mainly refers to commodities that are afraid of freezing or fear of solidification. The ventilation method is adopted to adjust the temperature inside the warehouse.