Why use a melt pressure controller?

As discussed in the section on melt pumps the screw type pump used in an extruder is very good for melting the plastic and mixing it, but it is poor in constancy of output. The output is dependent upon back pressure, size and shape of pellets, temperature of each barrel zone, type of plastic, and a host of other factors. If precision of the end product is required, by far the preferable solution is the use of a melt pump.

If, for any reason, that is not practical, the next best solution is to stabilize the melt pressure at the input to the die by a melt pressure controller. The flow of any fluid through an orifice, such as the die, is directly proportional to the pressure and inversely proportional to the viscosity of the plastic. Stabilizing the pressure does not do the entire job, but it will certainly help. Melt pressure control is a standard feature in the Harrel CP-873 DIGIPANEL^® controller, as furnished on the TIGER series of extruders. The PC-610 1/4 DIN Melt Pressure Controller may be used to upgrade existing extrusion lines.

The PC-610 MELT PRESSURE CONTROLLER.

• STABILIZES MELT PRESSURE AT THE DIE. Helps to stabilize throughput.
  
  
• MONITORS HEAD PRESSURE AND DIFFERENTIAL SCREEN PRESSURE. Indicates head pressure and drop across screens on auxiliary display.
  
  
• SAFETY PRESSURE SHUTDOWN. Warns of overpressure and shuts system down if operator does not act.
  
  
• AUXILIARY ALPHANUMERIC SCREEN. Displays cause of last shutdown, set points, calibration data, diagnostic data, etc.
  
  
• COMPUTER COMPATIBLE. May be monitored and set from Central Console or external computer.

For full details, fill out inquiry form or call Harrel at (203) 866-2673.

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