1. GRAVITROL ® Extrusion Control

2. 2 Closed control loop: GRAVITROL ® By the loss in weight in the weigh hopper over a time interval GRAVITROL ® measures the extruder output. The GRAVITROL ® computer and the extruder drive module ensures that the extruder‘s output is always equal to the debit.

3. 3 computer  … …  computer

4. 4 Applications: Blown film extrusion Cast film extrusion Sheet extrusion Cable extrusion Profile extrusion … All extrusion processes which allow to measure the extruder‘s throughput gravimetrically (flow fed extruders)

5. 5 Different line speeds Parameters, that cause problems without gravimetric extrusion control: Polymer density Bulk density Melt temperature Polymer viscosity Different conditioned polymer Change in blend reciepe Tolerances due to screw and barrel wear Changes in screen pack condition Changes of temperature Varying extruder power

6. 6 This is GRAVITROL ® able to do : Ensures product quality and economic operation GRAVITROL ® is like „cruise control“ for extruders Conversion of an extruder into a gravimetric metering element with exactly defined mass throughput (accuracy of ± 0,5% ) Ensures exact layer ratios Simplifies ramping up and down a line Smooth changeover from manual to automatic Synchronizes the extruder with the haul-off (also while ramping up and down a line) with an accuracy of ± 0,5%.

7. 7 Processes and product variables that can be controlled with GRAVITROL ® :

8. 8 Increase in profit with GRAVITROL ® by: Reduced labor costs and reduction of human-made errors Automatic ramping up and down a line results in o Processes optimised in time o Final product is always in specification Use of material can be adjusted very close to the minimum tolerances Reduction of waste The system learns the extruder‘s ramping curve by its own (normally this takes labor and time and errors can be made) Can be used instead of a melt pump (much more expensive); except in fiber processes

9. 9 GRAVITROL ® : typical application Production of high energy cables:

10. 10 GRAVITROL ® : typical application Blown film extrusion

11. 11 Ramping up and down a line: Typical extruder throughput curve  not linear m’ 0 Extruder speed in % 100

12. 12 Ramping up and down a line When ramping up a line for the first time the system learns the extruder curve by creating a step ramp. The evaluated function will be saved to the GRAVITROL ® computer memory and is base for the exact control of the extruder output. Extruder speed time

13. 13 GRAVITROL ® adjusts the extruder speed in a way that the throughput is always equal to the debit. Throughput control with GRAVITROL ® : m‘ [kg/h] time Extruder speed [min -1 ]

14. 14 Components of a GRAVITROL ® system EXB GRAVITROL ® Computer Features and function: 32-Bit Mikrocomputer (contains all necessary control algorithms for an accurate extrusion control) Operator panel (for the operating personnel) with user-friendly surface

15. 15 Components of a GRAVITROL ® system HGB weigh hopper Features and function: different hopper sizes for throughput up to 2.000 kg/hHigh resolution load cell (resolution 1:1.000.000DSP (Digital Signal Processor) weigh modulematerial drain valve and door (depending on the model)loading platform for vacuum reciever or swing gatesteep wall hopper for regrind material available

16. The function of the HGB weigh hopper can be replaced by either:a continuous gravimetric blender with weigh downcomer ora GUARDIAN ® gravimetric batch blender with HGC- weigh hopper 16 Components of a GRAVITROL ® system

17. 17 Components of a GRAVITROL ® system features and functions: 2 inputs for encoders 8 outputs for: 1 EXL + max. 7 EXD or max. 8 EXD connection to Mini-Op via ethernet port.

18. 18 Example: GRAVITROL ® system Mono-extrusion output control only for the use of raw material (i. e. PE, PP, …) or pre-blend EXB GRAVITROL ® Computer EXD HGB weigh hopper Material conveyance Extruder

19. 19 Example: GRAVITROL ® system Mono-extrusion output control and haul-off control for the use of raw material (i. e. PE, PP, …) or pre-blend Line speed module EXD HGB weigh hopper Material conveyance Extruder EXB GRAVITROL ® Computer EXL

20. 20 Example: GRAVITROL ® system Co-extrusion with 3 extruders output-, layer- and haul-off control using X-series continuous gravimetric blenders Line speed module EXD Material conveyance Extruder EXB GRAVITROL ® Computer EXD Extruder EXD EXL X-series continuous gravimetric blender

21. 21 Example: simplified GRAVITROL ® system with a GUARDIAN ® blender and a HGC weigh hopper* Mono-extrusion output control Installation follows the haul-off speed use of a GUARDIAN ® blender and a HGC weigh hopper EXLOX Line speed encoder EXD HGC weigh hopper for GUARDIAN ® GUARDIAN ® gravimetric charge blender Extruder EXB GRAVITROL ® Computer Customer supplied haul-off control +/- (or manual operation control) *: This GRAVITROL ® system represents a simplified low-cost solution which is often chosen in lines using gravimetric batch blenders. The haul-off has to be controlled manually by the operator. The GRAVITROL ® system takes care of the correct extruder throughput referring to the current line speed. The system always follows the line speed.

22. 22 Data recording for preparing a quotation: In this data sheet all necessary data concerning throughput and extrusion process are caught