batte melt pump manufacturers analyze the common forms of melt pump shaft seals

Zhengzhou Batte is a domestic professional high-temperature melt pump R&D and manufacturing enterprise with decades of experience in R&D and production of melt pump equipment, a number of national patented technologies, and provide high-standard, high-performance melt pump equipment.

For every running melt pump, some form of sealing of the drive shaft is required. The seal can choose magnetic seal, packing seal, spiral seal, single or double mechanical seal, lip seal or a combination of several previous seals. According to the different types of melt pumps and different applications, the sealing system is selected. The choice of seal type is determined by process parameters. Pressure, temperature and viscosity are the decisive factors for choosing a shaft seal.

Screw seal

Spiral seal is the standard sealing form of Bart ZB-B melt pump, but it can also be used for ZB-H high temperature and high pressure melt pump. It is a dynamic seal used for high viscosity and positive inlet pressure. Can be designed with heating or cooling jacket. This dynamic seal is suitable for high pressure and high temperature. Its application range is limited by the inlet pressure and the viscosity of the pump medium (minimum 10 Pas). If necessary, the viscosity can be increased by cooling the jacket.

Packing seal

In the ZB-F reactor melt gear pump, the packing seal is a very simple and strong shaft seal. According to needs, it can be designed as a double packing seal with flushing fluid. Braided fillers made of graphite and reinforcing fibers are usually used, but other special materials can also be selected as required.

Spiral seal and packing seal

Spiral seal is a dynamic seal, so it is often used in conjunction with packing seal. This form ensures that external air will not enter the pump and the reactor when the melt pump is stopped.

Spiral seal with lip seal

Spiral seals can also be used in conjunction with lip seals (radial shaft seals). Like the packing seal, the flushing fluid acts to isolate the air, ensuring that the air will not enter the pump through the shaft seal when the pump is stopped.

The shaft seal of high-temperature melt pump usually adopts a single sealing method, such as screw seal, packing seal, etc. Usually, after a certain period of use, the shaft seal of the melt pump will fail, causing material leakage in the melt pump. In response to this phenomenon, the Bart melt pump manufacturer adopts a spiral packing combined sealing method to effectively improve the service life of the melt pump. For the spiral seal, it is designed with reference to the working principle of the spiral pump. The multi-head spiral groove installed on the inner hole of the sealing sleeve forms the reverse flow of the melt, and the reverse thrust is sufficient to prevent the melt medium from leaking out.

Advantages of spiral seal: It is a non-contact seal with good mechanical properties such as compression resistance, tensile resistance, and bending resistance. For the screw and packing combined shaft seal, zero leakage can be achieved; the screw and packing combined seal melt leakage is large and the measured value is less than 0.015kg/d; not only the problem of short-term failure of the pump packing shaft seal is successfully solved, but also The application of the spiral packing combination seal in the dynamic seal of high-viscosity fluids. The long periodicity and non-leakage of the screw and packing combined shaft seal ensure the safe, stable, long, full and excellent operation of the high-temperature melt pump, and at the same time provide a reliable guarantee for increasing the production load. To learn more about relevant high-temperature melt pump prices or relevant cases, info@battemachinery.com.

When installing and using the melt metering pump with packing seal, the position of the sealing gland should be adjusted in time to ensure the best sealing state. For pumps with screw seals, if cooling water auxiliary sealing is required, a 1/8 or 1/4NPT joint should be installed on the screw seal assembly, and then the water source should be connected. For small displacement pumps, do not let the cooling water affect the heating of the pump body.