Foam machinery and equipment work after pre-launch

A certain amount of foaming agent and water vapor are retained in the pre-expanded beads of the foam machinery and equipment. When they are discharged from the machine, they will condense into a liquid, and the liquid foaming agent will be dissolved into the polystyrene, which will quickly reduce the pressure in the bubbles. , There is negative pressure (partial vacuum) in the bubble, and the beads are very soft and easily deformed. Therefore, when air is sent, try not to make the wind pressure too large. The inner wall of the duct should be as smooth as possible, and the bending radius should be as large as possible (to reduce collision resistance). The pipeline should be a good conductor of electricity, and the entire line must be grounded to avoid static electricity. Sparking, the transmission speed should not exceed 8m/s to avoid damage to the beads.

    The beads of the foam mechanical pre-expander are moist. After being discharged from the pre-expander, they absorb air and suddenly encounter cold, which causes the foaming agent in the honeycomb cells to condense and form a negative pressure in the cells, so the beads are in After pre-expansion, it must be placed for a period of time. On the one hand, it is dried, and on the other hand, it is allowed to infiltrate the air to eliminate the negative pressure, so that the internal pressure and external pressure in the cells are balanced, so as to prevent the cells from collapsing and make the beads elastic.

    The process of drying, cooling and stabilizing the cell pressure of the EPS beads just out of the pre-expander is called maturation. Maturation improves the further expansion of the pre-expanded beads during the molding process, the sintering between beads and the elasticity of the beads, which is beneficial to improve the quality of EPS products.

    During the curing process, the beads are cooled by air, and the foaming agent and water vapor in the pores of the cells are condensed into liquid, so that negative pressure is formed in the cells. At this time, the air penetrates into the cell through the cell membrane to balance the pressure in the cell with the external pressure, which will make the pre-expanded beads elastic.　
　
    The maturation can be divided into two methods: natural maturation and pressure maturation. Under cool, dry, and ventilated conditions, allowing natural aeration is called natural maturation. Adding gas (air, nitrogen) to the pre-expanded beads after natural maturation in a sealed container to make them have a certain pressure and inflate it, which is called pressurized maturation.