Structure of submersible pumps

1. What is a pump’s \"balancing mechanism\"? Why does a pump’s \"balancing mechanism\" require liquid in order to achieve balance? The purpose of the pump’s balancing mechanism is mainly to balance the axial and radial forces of the pump, such as balance discs, balance holes, balance pipes, and the like ； It’s not that all of them require this; in the case of multi-stage pumps, the axial force can be reduced to some extent by arranging the impellers opposite to each other, or many pumps use double-suction impellers, which can automatically counteract most of the axial force. 2. Why does a different fluid affect the internal structure of the pump? ? The fluid type plays a significant role in the pump’s performance; for example, there are substantial differences in the design of impellers between pumps used for clean water and those used for sewage. The material choice also matters, as changes in the medium used can lead to a shorter service life and more frequent failures. 3. What is the purpose of testing the resistance between the motor phases and the pump casing before starting the machine? The purpose of testing the insulation resistance to the chassis is similar to that of testing the insulation resistance to ground; generally, the required insulation resistance from the chassis is even higher.

Thank you for your advice. So, what is the main purpose of testing the insulation resistance of the enclosure? Is it a commonly used method? What problems can occur during operation if the resistance isn’t high enough? If there is a submersible pump for LPG/LNG, it’s not possible to create an LPG/LNG environment for it before operation; so how can we carry out the debugging?

Testing the insulation resistance between the casing and the windings is primarily to ensure the motor’s insulation properties, as there is a concern that the insulation might be damaged during transportation or due to improper storage. The insulation of the motor is closely related to environmental humidity; if it exceeds the specified technical parameters, the submersible pump cannot be installed. The motor needs to be disassembled to inspect the windings. For the commissioning of submersible pumps, whether it is LPG (liquefied petroleum gas) or LNG (liquefied natural gas), they must be kept dry before commissioning; testing can only proceed after the actual fluid enters the system. In the factory, the submersible pump is actually tested with actual fluid, and a complete test report is provided.