Principle
With a defined volume, polymer melt is pressed with a defined volume through a melt filter and the pressure in front of the melt filter is monitored. Particles (contaminations, agglomerates in pigments, etc.) are caught in the filter and the pressure increases in front of the melt filter. The calculation of the pressure filter test (FT), according ISO 13900-5, starts at the end of the test by determining the initial pressure (P start) and the final pressure (P max) divided by the pigment weight.
Main applications
- Testing of pigment or additive dispersion
- Inspection of contamination in virgin and recycled polymers
Special Features
- By using a by-pass valve, the melt flow can be by-passed in front of the screen. This enables an interruption of the melt flow without having to stop the extruder or the melt pump. A change of the screen can easily be done while purging both, the extruder and melt pump. But the most decisive advantage is that after having changed the screen the extruder and the melt pump need not to be started again.
- First, the new screen is positioned in a pre-heating position and then in the actual testing position for the next trial. Therefore, the time needed for the test screen to adapt thermally to the testing equipment is no longer necessary.
Advantages
- Extremely reduced downtime
- Reduction of the staff requirement
- Extremely safe in operation
- Manually operated
- Melt valve for continuous measuring without stopping the extruder
- Melt pump for constant melt flow-rate
- Melt filter preheating
- All design parameters and the evaluation correspond to the
ISO Standard 23900-5 (or EN Standard 13900-5)
