Melt pumps [EXTRU] for extrusion

Efficient. Pulsation-free. Gentle.

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.

Request for a melt pump quotation

Please fill out the following form so we can create an offer that is exactly customized to your needs. One of our sales engineers will examine your request and contact you to discuss your personal solution.

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Design examples for melt pumps [EXTRU]


Advantages at a glance

  • Electric heating
  • Cooled threaded shaft seal
  • Housing design
  • Drive shaft on both sides
  • Optimal herringbone gearing

  • Electric heating

    The housing can be heated electrically. A separate cover heating is also possible.

  • Cooled threaded shaft seal

    The threaded shaft seal can be equipped with a cooling unit to increase viscosity. A “bleeding bearing” variations is available for particularly sensitive media. The bearing lubrication flow is guided outwards so that any stressed material is not returned to the main flow.

  • Housing design

    The housing may be designed in different variations. A round and a square design are available as standards. But customized designs are also possible. A version for fast changing colors is optional as well.

  • Drive shaft on both sides

    To prevent the drive shaft of the pump being driven/pushed out of the casing with high pressure on the suction side (flow pressure of the extruder) the drive shaft must be relieved. It is guided out on both sides of the casing and sealed so that atmospheric pressure is present on both sides of the drive shaft. The shaft runs with relief.

  • Optimal herringbone gearing

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

[Translate to English:] Schmelzepumpe EXTRU3 von WITTE

Technical data

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
Electric through heating cartridges · Cover heating optional
Friction bearing
Tool steel · NiAG (nickel-silver) · Aluminum bronze · Special materials · optional with coating

Operating parameters

Up to 40.000.000 mPas
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


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.

Meltpump on moveable cart

Melt pump on mobile cart with angular gear and 90 ° angled motor.

A variety of variants are possible, for example:

  • Melt pump on mobile cart with angular gear and 90 ° angled motor (vertically upwards)
  • Melt pump on a mobile cart with angle gear and 90 ° angled motor (horizontal to the side)
  • 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

Seal variations for melt pumps

References melt pumps

Melt pump of angular design with special flange
Melt pump Extrusion pump round design
 Melt pump in round design on a base frame
[Translate to English:] Schmelzepumpe auf fahrbahrem Wagen
[Translate to English:] Schmelzepumpe für ABS Filamentherstellung
[Translate to English:] Schmelzepumpen mit kundenspezifischer Adapterplatte
[Translate to English:] Schmelzepumpe für die Herstellung von 3D-Druck HDPE Filament
Schmelzepumpe zur Herstellung von medizinischen Schläuchen im Extrusionsverfahren.

Schmelzepumpe zur Herstellung von medizinischen Schläuchen im Extrusionsverfahren.