How to operate an EPS pre-expansion machine?

How to operate an EPS pre-expanding machine? Below, the EPS pre-expanding machine manufacturer will introduce its key operating points and precautions.

 

Open the side door of the pre-expanding machine: Check for water bubbles or other debris inside the machine, and check for water bubbles on the thermometer probe. Then tighten the side door screws. Adjust the outlet height to the required height and check if the exhaust system pipes are unobstructed.

 

Check the total steam pressure; the pressure should not be lower than 3.5 kg/cm³. Simultaneously check if the compressed air pressure of the propeller is lower than 4.5 kg/cm³.

 

Start the pre-expanding machine: Stirring motor, exhaust fan motor, feed fan, vulcanizing bed dryer, and feed motor.

 

Open the steam inlet and outlet valves to preheat the preheater. Generally, the preheating temperature should reach approximately 80℃. After adjusting the feed speed, promptly adjust the feed speed, steam size, outlet height, and compressed air intake. Based on the bulk density, shrinkage rate, elasticity, and roundness of the bubble particles, stabilize the operation process as quickly as possible to achieve the specified bulk density.

 

Generally, the temperature range for one propulsion cycle should be controlled between 90~95℃. Meanwhile, the model and type of the propulsion machine, product stacking density requirements, steam quality, and exhaust system conditions must be considered in conjunction with the actual situation of each manufacturer. However, it is generally not recommended to pre-expand at excessively high temperatures or with excessively low pre-expansion rates. It is suggested that customers control the propulsion rate of ordinary materials at 92-95℃ and 13-16 g/L, flame-retardant materials at 12-18 g/L, fast-expanding materials at 15-17 g/L, and high-speed materials at 11-12 g/L, to improve the internal and external quality of expanded polystyrene products. To adjust operating conditions promptly, during the pre-expansion process, samples must be frequently taken from the pre-expander for weighing to observe the bulk density of the foam particles.