MELT PUMPS [EXTRU] FOR EXTRUSION

Efficient. Pulsations-free. Gentle

ExtruCore AT

The new design for WITTE melt pumps

The technical revision ensures, on the one hand, lower stress on the bearings and thus a lower bearing temperature and, on the other hand, significantly improved volumetric efficiency. Shear and temperature stress on the polymer are thus significantly reduced and product quality increased.

Wear on core components such as friction bearings and gear shafts is reduced to a minimum.

Advantages:

Lower bearing temperature, thus less stress on the polymer
Minimized wear
Various materials available for bearings, shafts and housings
Optional terminal box for cartridge heaters
Increase in throughput for pumps with the same center distance

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Robust and flexible

The robust design and wear-resistant materials make the EXTRU indispensable for extrusion. It can also be used to transport natural rubber and soft PVC through different special designs.

The WITTE fast-changing color design is perfect for master batch applications with frequently changing colors.

Melt pumps for extrusion

The extrusion gear pump is mainly used in connection with extruders or kneaders. They lower the naturally existing pulsation and uneven transportation, particularly of single-screw extruders.

The extrusion pump is also used as a melt pump. It takes over the establishment of the required transport pressure, which is needed for the downstream equipment.

Efficient pressure build-up

In the gear pump, the pressure build-up occur significantly more efficiently than in the extruder itself. The extruder is relieved through the use of an extrusion pump. Significantly less energy or heat is added to the polymer. The melt pump thereby contributes to the gentlest possible transportation. The EXTRU pump is indispensable for the production of precise foils or micro-granulate.

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Design examples for melt pumps [EXTRU]

Advantages:

Electrical heating
Cooled threaded shaft seal
Housing design
Double-sided drive shaft
Optional herringbone gearing

Electrical heating

The enclosure can be heated electrically. Separate lid heating is also possible as an option.
Cooled threaded shaft seal

To increase viscosity, the threaded shaft seal can be equipped with a heat sink. For particularly sensitive media, a "bleeding bearing" variant is available. Here, the bearing lubricant flow is diverted to the outside so that stressed material does not get back into the main flow.
Housing design

The housing can be designed in a wide range of variants. A round and a square design are available as standard. But customised designs are also possible. A version for quick colour changes is also available as an option.
Double-sided drive shaft

To prevent the drive shaft of the pump from being driven/pushed out of the housing when there is high pressure on the suction side (delivery pressure of the extruder) of the pump, the drive shaft must be relieved. It is led out of the housing on both sides and sealed so that atmospheric pressure prevails on both sides of the drive shaft. The shaft runs unloaded.
Optional herringbone gearing

For particularly sensitive media, we offer a special toothing for the EXTRU melt pumps. The herringbone gearing reduces the natural pulsation of the extruder and guarantees a constant melt flow.

Technical data

Housing: Heat-resistant carbon steel, for example, 1.6582 · Stainless steel 1.4313 · optional with coating · optional with coating
Gear Shafts: Tool steel · Nitriding steel · Special steel · optional with coating · Helical gearing · Herringbone gearing (for transportation with very low pulsation)
Shaft seals: Threaded shaft seal · Stuffing box
Heating: Electric through heating cartridges · Cover heating optional
Friction bearing: Tool steel · NiAG (nickel-silver) · Aluminum bronze · Special materials · optional with coating

Operating parameters

Viscosity: Up to 40.000.000 mPas
Temperature: Up to 400°C
Suction pressure: Vacuum up to max. 120 bar
Transport pressure / differential pressure: Up to 250 bar. Special designs also for higher differential pressures
Pump sizes: From 4,7-22-22 (4,7 cm3/U – 10 kg/h) to 12.000-280-280 (12.000 ccm/U). Sizes with smaller gears for higher differential pressures are possible, p.e. 690-140-90.

Application examples for WITTE melt pumps from the EXTRU series

Plastics: PS · PET · PVC · PC · PMMA · HDPE · LDPE · LLDPE · PP · PEEK · POLYSULFONS · LICORICE · CHEWING GUM

Mounting positions EXTRU melt pumps

The melt pumps of the EXTRU series are very flexible in terms of installation. They can be installed in almost all installation positions, even if there is only limited space available. The flexible arrangement of the individual components makes it possible to optimally utilize even tight spaces.

Melt pump on mobile carriage with angular gear and 90 ° angled motor (vertical upwards)

Melt pump with cardan shaft, gearbox and motor in vertical row installation

A variety of variants are possible, for example:

Melt pump on mobile cart with angular gear and 90 ° angled motor (vertically upwards)
Melting pump with cardan shaft, gearbox and motor in vertical line installation
Melting pump with cardan shaft, gearbox and motor in horizontal line installation
Melt pump on mobile cart with angular gear and 90 ° angled motor (pump vertically upwards)
Various other installation options