CSC

CSC Screen Changers are used in continuous production. On the material inlet side, the melt flow is divided in two and
carried to screens I and II. An additional screen support plate allows 98% of the overall filter area to be used for filtration. The optimized
channel geometry allows direct flow to and from the filter while at the same time significantly reducing the channel length.
This reduction improves the differential pressure level inside the flow channels and simplifies the cleaning process when changing
materials or colors. In addition, the selectable cross section allows much better control over the melt flow speed (residence
time in the heated machine) or over the pressure drop when processing highly viscous melts. After filtration, the two separated
flows come back together at the material outlet. When changing the screen, a screen bolt is first rotated out of the housing by
means of a hydraulic cylinder. This blocks that channel and production goes on through the other screen – continuously. So that
this continuity does not work against the process, the screen changer’s overall layout is tailored to match the extrusion output.
The contaminated screen can now be replaced with a new one. The screen bolt is now put back in the housing, taking into consideration
the vent positions. The second screen is replaced in the same manner.

Screen changer FSC

Components of the screen changer FSC from Maag Pump Systems were further developed to address the challenges of PVC production: PVC extrusion is a continuous process, which takes place in a narrow temperature range of 160 to 200°C. If the upper limit is exceeded there is a danger of the melt overheating and burner formation. A unique channel guide prevents a reduction in the flow speed and ensures that conveyance is continuous and constant. The 8’er contour of the screen mounting plate enables the cylinder contour of the double screw extruder to be continued up to the perforated plate. The screw tip is thus able to convey up to just before the screen. A special coating prevents the melt sticking. The forming of local overheating during the heat up is prevented with the help of an oil temperature device. On the other hand, during the rundown the liquid tempering prevents heat accumulation. The heat in the channels is systematically dissipated. A further feature of the FSC is the heatable screen plate. Before a screen change the stand-by cavity can be set to operating temperature to ensure temperature constant production. Accessibility to the screen plate and the adjacent housing parts is assured at all times.  The pressure adaptive gasket system between the screen plate and housing is used for leak-free conveyance at high pressure. With this the contact pressure increases on the gasket system when the internal pressure increases.

The new ONE....... The Recycling Screen Changer

From now on, the latest generation of Screen Changers made by Maag also meets all requirements of direct recycling processes, such as the fabrication of food-wrapping films from PET bottle flakes in one process step exclusively.

In the newly developed product line of CSC/BF-PE Screen Changers, this has become possible thanks to the fully automatic cleaning of the screens which can be adjusted to any kind of process.

The quantity of material which is needed for backflushing of the screens is collected in a permanently flushed accumulating space and will then clean the dirty screen cloth outside the production process by backflushing.
In this way, variations in pressure and volume are to the greatest extent avoided and the effects on the final product are minimized.
The flow channel geometry which is entirely free from any dead spots as well as the free setting of backflush pressure, quantity and time facilitates the processing of all marketable recycling plastics and thermally sensitive polymers. Upon the introduction of production line specific set points into the control system, the backflush filter changes to the operating mode and starts the fully automatic cleaning of the screens which is controlled by pressure or time and depends on the level of dirt accumulation. Recycling Screen Changers are based on the well-proven double-piston design which does without any additional seals and ensures a reliable and leak-proof operation.
The product line of CSC / BF-PE Screen Changers will be available in all sizes and can be incorporated into any existing extrusion lines belatedly.

Extrusion systems

Innovation, quality and economic efficiency stand in the foreground for ourselves and for our customers. In order to achieve our customers’ satisfaction, we enlarge our product range steadily. Upon request, Maag Pump Systems delivers systems completely adapted to your specific use, e.g. consisting of an extrex® gear pump, start-up valve, a screen changer and gear units mounted on a support carriage. The advantages of such systems from one hand are convincing:

• Interfaces are optimized

• Individual adjustment to the requirements of the specific application

• Service from one hand

• qualitative, price-optimized systems

• reduced overall length due to flangeless connection

extrex® gear pump

Maag has been the market leader for many years in the Extrusion sector. The working principle of the gear pump improves the commercial profitability of the sector’s continuous extrusion processes.

The modular construction of the extrex® gear pump makes it suitable for a number of extrusion applications.

Employing an extrex® gear pump into the process, the extrex® gear pump takes the function of delivering constant flow of polymer to the pelletizer or die, widely independent of their pressure requirements. Due to the excellent pressure built up capabilities of the extrex® gear pump the compounder or mixer then can concentrate on its main function of mixing and melting the polymer.

The positive displacement characteristics of an extrex® gear pump significantly reduces the specific energy input (SEI) into the polymer melt. This reduces the average temperature increase of the polymer melt stream. The same characteristic also decreases the variations of the pellets, or in case of direct extrusion processes, allows keeping tighter tolerances in your end product. Additionally less waste and off-spec material will improve the profitability of the whole plant by saving raw material costs too.

The rubber manufacturers have also now taken advantage of Maag’s gear pumps to improve the quality and output of their processes.