Application range of melt extrusion screen changer

Melt extrusion screen changer used in extrusion line, for example, extrusion filtering of polymer melt , compounding extrusion granulator of engineering plastics , recycling granulator of plastic, extrusion of blown and cast film, extrusion of sheet material, extrusion of pipe and profile, rubber mixing, extrusion of ceramic etc. When selecting different structure screen changer, it is required according to the material characteristics and requirements of different extrusion process, refering to characteristics of various screen changer.

Manual (lever type) screen changer

Lowest cost, small size, large pressure fluctuations. Used the occasion that allow stop the line to change the screen. Simple structure, leak more likely, the maximum application temperature is 260oC. Can only be applied to small extruder (screw diameter less than 120mm).

Hydraulic slideplate srceen changer

Lower cost, suitable for the occasion that fast changing screen (1.5 seconds), widely use, any extrusion lines allow to large pressure fluctuations and a small amount of air entering when changing screen can be applied. The possibility of leaking material is large When extruding the low viscosity material, the maximum application temperature is 280℃.

Hydraulic single piston screen changer

Cost-effective, low operation cost, can quickly change screen without stoping the line. Sealing, suitable for low viscosity melt, but the pressure fluctuations higher, the maximum application temperature is 300℃.

Hydraulic dual piston screen changer

Change screen without stoping the line, the pressure fluctuation is small, good sealing performance, large area filters. Higher manufacturing costs, higher skill requirements for operation, the material residence time is longer, the maximum application temperature is 300℃.

Automatic screen changer

Change screen without stoping the line. The pressure fluctuation is small, automatic change by PLC controlled, large filtration area , particularly suitable for extrusion process which require a very stable pressure , like strand pelletizing . Manufacturing costs are high, the material residence time is longer, the maximum application temperature is 300℃.

Manual (wheel type) screen changer

The slide action of changer is driven by a hand wheel rotation. Labor-saving, low cost, suitable for the production line that allow a few minutes to stop. Can only be applied to small extruder (screw diameter less than 120mm).

Belt type screen changer

Steady differential pressure, the material residence time is short, less operator intervention. Manufacturing costs are high, running costs are high, melt leakage.

Diverter valve

Use for dumping the degrade and unqualified polymer out of extruder when restart the machine after shutdown, but not through the mold, or rise the function of discharging flow when the mold are blocked up.

Strand pelletizing die