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Explanation of the three commonly used sealing forms of polymer kettle bottom discharge pumps

The polymer tank bottom discharge pump is suitable for conveying the medium and high viscosity melt medium in the vacuum reactor. It uses a large suction port. Under vacuum conditions, high viscosity materials can also be sucked into the gear pump. The polymer tank bottom discharge pump can provide a circular inlet flange directly connected to the reactor, and the gear pump is clamped between two flanges. The suction port is larger and the inlet distance is shorter. There are three commonly used sealing forms for polymer kettle bottom discharge pumps: double mechanical seals, vacuum spiral seals with stuffing box, and vacuum spiral seals with lip seals.

reaction kettle polymer melt pump

Double mechanical seal form

The standard double-end mechanical seal is suitable for the inlet from vacuum to 15Bar, and the material viscosity from 0.2 to 1,000,000cP (mPas). The high temperature of the material is about 300°C. Higher pressure and temperature require special design. Material viscosity: 0.2-1,000,000 mPas Working temperature: ≤400℃ Pump inlet pressure: vacuum—15Bar

Vacuum screw seal with stuffing box

The vacuum spiral seal is a special spiral seal, which can be equipped with a heating or cooling jacket. The needle valve is used to adjust the return flow to the suction side, so that the blocked melt forms a barrier. This makes it applicable when the suction side is vacuum. Because it is a dynamic seal, it is usually combined with a packing seal with a buffer solution. This combined seal can also prevent air from entering the reactor when the gear pump is stationary. Material viscosity: 10-40,000 Pas Working temperature: ≤450℃ Pump inlet pressure: from vacuum to 40Bar

Vacuum screw seal with lip seal

As another option, vacuum screw seals can also be combined with lip seals. When the pump is briefly stopped, the buffer in the lip seal prevents air from entering the pump through the shaft seal. Material viscosity: 10-20,000 Pas Working temperature: ≤300℃ Pump inlet pressure: from vacuum to 15Bar

Zhengzhou Batte provides various types of melt gear pumps that are used in conjunction with screw extruders. At present, various domestic rubber and plastic extrusion production lines, such as pipe extrusion production lines, wood-plastic extrusion production lines, and composite pipe complete sets of extrusion production lines , Granulation production lines, etc., all need to be equipped with melt pumps to improve the output of the entire production line and the quality of products. Learn more about info@battemachinery.com

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