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The principle of foam machinery

2023.05.11

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 out of the machine, they condense into liquid, and the liquid foaming agent dissolves into polystyrene, so that the pressure in the bubbles is quickly reduced. , Negative pressure (partial vacuum) appears in the bubble, and the beads are very soft and easy to deform. Therefore, when the wind is blowing, try not to make the wind pressure too large, the inner wall of the air 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. For ignition, the conveying speed should not exceed 8m/s to avoid damage to the beads.
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 out of the machine, they condense into liquid, and the liquid foaming agent dissolves into polystyrene, so that the pressure in the bubbles is quickly reduced. , Negative pressure (partial vacuum) appears in the bubble, and the beads are very soft and easy to deform. Therefore, when the wind is blowing, try not to make the wind pressure too large, the inner wall of the air 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. For ignition, the conveying speed should not exceed 8m/s to avoid damage to the beads.
The beads just out of the foam mechanical pre-expansion machine are all wet. After being released from the pre-expansion machine, due to the absorption of air, they 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 the air. After pre-hairing, it must be left for a period of time. On the one hand, it is dried, and on the other hand, it is infiltrated with air to eliminate 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-expanding machine for a certain period of time is called aging. Aging improves the further expansion of the pre-expanded beads during the molding process, the fusion between the beads and the elasticity of the beads, which is conducive to improving the quality of EPS products.

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