According to GB requirements for bulk density determination, outside temperature is below 0°C, corn moisture below 23.0% is measured weight density, corn moisture above 23.0% cannot be measured weight density; outside temperature is above 0°C, moisture is between 18% and 23% For every one percentage point increase in water content, the bulk density factor of 5g/L is important. The coefficient of friction coefficient of corn grain is the main factor that determines the change of corn bulk density. The temperature above 0°C will cause condensation on the grain surface, which will increase the friction between the grains or the grain and the capacity of the cylinder wall, resulting in the actual measured bulk density of the corn being less than its actual bulk density. Therefore, the supplemental coefficient is added. Among them, the bulk density of corn can be measured by a corn bulkhead. MMA Welding Machine,MMA Welder,IGBT Welding Machine Electric And Machine Co., Ltd. , http://www.ylweldingmachine.com
Food is a wet substance composed of dry matter and moisture. The water contained in a corn can be divided into free water and bound water according to the nature. The combination of moisture is chemical bonding of water, physical and chemical bonding of water, and physical mechanical bonding of water. When the moisture content of corn is more than 20.0%, during the precipitation process, most of the water is free water in corn and a small part of physical and mechanical water. It can be said that this part of water is relatively easy to volatilize under the effect of temperature. The corn grain morphology changes during precipitation. Epidermal morphology will change from moisture to moisture, from loose to tight, from soft to hard, from wet to dry series of changes, there will be dry cracking, peeling and other phenomena. Embryos appear tight and pleated. Corn kernels appear soft and soft, and the roughness of the epidermis increases. It is obvious in the process of high temperature rapid precipitation. When the water content of corn moisture is less than 20%, the free water and physical-mechanical bound water content in the epidermis and embryo of maize kernel are less than the free water and physical-mechanical bound water content of the endosperm, and the epidermis is already in stereotype. Therefore, corn with less than 20.0% moisture does not undergo much change in the epidermis during precipitation. The epidermis changes occur mainly during the precipitation of corn with moisture above 20.0%.
In the precipitation process of corn, the roughness of the grain surface of the grain increases, which is the main factor that increases the friction coefficient between the grains of the grain, so that the bulk density will drop dramatically. The data showed that the moisture content of the epidermis and embryos of the seeds below 20.0% is lower than that of the whole grains; the external morphology of the epidermis has been established. The morphological changes of the epidermis and embryos occurred mainly in the precipitation process of more than 20.0%. It can be seen that the changes in the smoothness of the corn affect the changes in the bulk density of the corn during the evaporation process of the corn moisture. The use of multiple drying methods to maintain the epidermal moisture evaporation rate, reduce epidermal changes, and precipitation within the corn, making the skin slowly shrink, increase the smoothness, reduce the friction coefficient to increase the bulk density. The measurement of bulk density can be measured by corn bulk density. The epidermis will dry out little by little under the effect of high temperature. When it is dry, it will be cooled, and the moisture of the epidermis will be mixed with the moisture of the embryo and the endosperm, and then the next round of precipitation will be carried out. It is a good method to control the distribution speed of epidermis water to reduce the skin roughness and ultimately reduce the weight reduction. Therefore, when drying the same moisture, the same grain of food, the dryer of two hot air chambers and two cooling chambers is more important than the capacity of the dryer of one hot air chamber and one cooling chamber. The grain surface is rough, the bulk density is small, and the bulk density is low. The seed coat is smooth, the bulk density is small, and the bulk density is increased. Therefore, it is possible to use a constant temperature multiple precipitation cooling method to dry the corn to reduce the coefficient of friction of the grain skin to increase the bulk density. The electronic grain container is an instrument that is specifically designed to measure the bulk density of corn. It is also possible to reduce the degree of changes in corn epidermis by reducing the temperature of the dryer, and to slow down the epidermal moisture evaporation rate to increase the bulk density. However, the cost of this method is higher.