Automatic screen changer DHW-150
The automatic screen changer is a compact, self-contained screen changer that eliminates the need for hydraulics, screen packs, breaker plate cleaning or replacement, with no electric motors or hydraulics.
multi-type of control system
The screen change can be controlled by:
-A timer which is preset
-Change in pressure,
-temperature controlled meter
Which process is used generally depends on the polymer, levels of contamination, pressure related issues, and processing requirements.
-Timer-based controller for lightly contaminated materials where constant speed is required. For example:
we can set the timer OFF 2 hours, and about 10 minutes ON, it means screen change interval is 2 hours, and 10 minutes is the time of screen change.
-Pressure differential controller which uses two melt pressure sensor. This is used for applications with heavier and variable contamination that requires screen replacement adjustments to maintain constant pressure and output.
we can preset the pressure add 0.6-1.0Mpa based on the actual pressure. For example : the actual pressure is 20Mpa, we can pressure the screen change pressure 20.6-20.1Mpa.
when the pressure raise to the preset, the screen will move forward automatically
-Controlled by the tempreture controll meter. we can preset it between 70-80 centigrade. the heater begins working, and when the temperature of the cooling water raise to the preset , the screen will move forward.
screen changing time
1. Cooling(blue) – water (8 –20 degrees C) is circulating in the entrance and exit blocks.
2. Heating (red)– When a screen change is needed , the heater begin to work
3. Screen move forward - controled by the timer or pressure sensor.the blocked screen move forward. This also moves the contaminated screen across the flow of
plastic and a fresh sreen section enters.
Application
1. Plastic
pipe production line
2. Pipe, PA, PET and
PVC sheet extrusion lines
3. Pelletier, granulation, Non-woven, Plastic recycling and Monofilament machine
