How to prevent dry pumping of centrifugal pumps equipped with mechanical seals ？

To prevent dry pumping of centrifugal pumps equipped with mechanical seals, efforts should be made from three aspects: seal management, equipment maintenance and operating conditions ‌. 

The core is to avoid air entering the pump body and dry friction on the sealing surface.

Sealed management

Strictly inspect the dynamic and static seals: During maintenance, it is necessary to ensure that the seals are not damaged or aged to prevent air from leaking into the medium through the pipeline or pump body. ‌

Select appropriate sealing materials: Choose wear-resistant and corrosion-resistant sealing materials based on the characteristics of the medium (such as salt, abrasive or high temperature)

Cover material (such as silicon carbide, ceramic), to avoid seal failure caused by material mismatch. 

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Control of operating conditions

Ensure a net positive suction head (NPSH) : Maintain sufficient suction pressure to prevent the vaporization or interruption of the medium inside the pump due to cavitation or insufficient flow. ‌

Avoid dry operation: Before starting, make sure the pump is filled with liquid. When stopping, keep the sealing surface lubricated to prevent damage to the sealing surface due to dry friction. 

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Equipment maintenance

Regular lubrication and cooling: Ensure that the sealing surface is lubricated by the medium itself (for water-based liquids, antifreeze should be added), and use isolation fluid to protect the sealing surface when necessary. ‌

Monitor temperature and vibration: High temperature or severe vibration may accelerate the aging of sealing materials. It is necessary to adjust the operating parameters or replace the sealing parts in a timely manner. ‌