Problems that should be paid attention to during installation and use After the filter element of the screen changer is removed, due to the residual polyester melt at the bottom, inner wall and inlet and outlet pipelines of the inner tank, if it is not removed, it is easy to be carbonized during the preheating process, and the screen changer is blocked when switching , Greatly shorten the life cycle of the screen changer. In view of the high temperature of the inner tank and the small space, the lower head must be disassembled each time before installation, first manually cleaned, and then blown back with gas, the effect is very ideal.
At the same time, pay attention to the following issues in use: If the preheating time is short, the resistance of the melt through the filter element due to uneven heating during switching increases, and the service life of the filter element is reduced. Therefore, the better preheating time should be 48h; it should be controlled The filter element has a large pressure difference, which can be switched in time to protect the filter element. The large pressure difference is 6.0MPa. After each switching, close the inlet and outlet valves of the cut screen changer to avoid internal leakage of the valve
Screen changer material selection: The screen changer of the polyester device adopts a candle-wick type pleated screen changer. The original material is 15μm steel mesh cloth. The online life of the screen changer is short. Under normal production conditions, it needs to be switched in 25-30 days. The screen changer is not easy to clean.
For this reason, the material was replaced with sintered metal fiber with good filtering performance. By comparing the two filter materials, it can be found that under the same filtering accuracy (15μm), sintered metal fiber has better filtering performance than steel mesh cloth.