1. The steam must be saturated steam, working pressure is 0.5 ~ 0.8 Mpa; dynamic pressure is 0.2 ~ 0.3Mpa. It is critical that the steam is saturated steam, because if the steam pipe is too long or too small, or the pressure of the boiler is not enough, then it is easy to form water vapor. If unsaturated steam enters the barrel of the pre-expander, it will make the surface of the EPS raw material contains too much water so that the raw material expansion ratio is difficult to achieve the same. So the steam inlet pipe diameter must be 3-2.5 inches and the pipes must be insulated well. The distance between the eps machine and the steam accumulator is normally 5-10 meters.
2. The working pressure of compressed air is 0.6 ～ 0.8Mpa, which must be purified and free of water and dust. The dynamic pressure is 0.5 ～ 0.6Mpa. The compressed air on the fully automatic batch pre-expander is mainly used to control the valves, cylinders on the pipeline and clean the pipes of the barrel. Because the solenoid valve spool at the discharge port has high precision, if it encounters dirty air, it is easy to cause the solenoid valve spool to be stuck, so that the solenoid valve coil is overloaded and burned. Therefore, before compressed air enters the EPS pre-expander, it must be filtered through a filter of less than 40u to completely remove the dirty things and moisture, and ensure the normal and stable operation of the pre-expander.
3. The EPS raw materials must be within the validity period and must be dry and powder-free raw materials. Because the foaming agent in expired raw materials has evaporated so that it can’t ensure the foaming ratio of the raw material. If there is too much powder in the eps raw materia, it will block the feeding port and the vent groove of the pre-expander barrel, making the eps pre-expander unable to produce normally.