Cooled Frequency Converter in Multistage Centrifugal Pump
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Solution Overview
Problem
Multistage centrifugal pumps with variable frequency drives face heating issues due to the control assembly, and existing cooling solutions either complicate the pump's construction or fail to effectively dissipate heat using both air and water cooling methods.
Innovation Solution
The control assembly is strategically located between the motor and the leak-tight chamber, in thermal contact with the partition wall, allowing heat dissipation into the pumped liquid, and enhanced by a cooling fan and heat-relief surface features, with quick-disconnect electrical connections for easy maintenance and a screen to prevent liquid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the control assembly is cooled using a pipe through which pumped water is channeled, then the cooling effect is improved, but the device complexity increases
Solution Approach 1:
The control assembly is merged with the partition wall structure, using the wall itself as the cooling medium carrier. The pumped liquid flows along the outer surface of the partition wall, which serves both as a structural separator and as a heat dissipation surface, eliminating the need for separate cooling pipes.
Solution Approach 2:
The partition wall performs multiple functions: it separates the pumped liquid from the motor/control assembly, provides structural support, and serves as a heat dissipation surface. This multi-functionality reduces the need for additional cooling components.
2Temperature
If the control assembly is located on the pump wall in thermal contact with pumped water, then the cooling efficiency is improved, but the ease of repair deteriorates
Solution Approach 1:
The control assembly is segmented from the motor and positioned on the pump wall in a separate location. This segmentation allows the control assembly to be cooled by pumped liquid while maintaining independent accessibility for maintenance and repair operations.
3Temperature
If air cooling is added to the control assembly, then the cooling effectiveness is improved, but the device complexity increases
Solution Approach 1:
The control assembly utilizes the pumped liquid that is already circulating through the pump system for cooling purposes. The liquid serves dual functions: pumping the required fluid and providing cooling medium for the control assembly, eliminating the need for separate cooling systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively dissipates heat generated by the control assembly, preventing overheating and facilitating maintenance while ensuring efficient operation and reliability of the pump.
Implementation Method 1
the heat generated by said control assembly during operation thereof to be conducted through said wall of the leak-tight chamber, and then dissipated into the pumped liquid circulating through the inside of said leak-tight chamber in contact with said wall
Implementation Method 2
a cooling fan coaxial with the mentioned shaft, said fan being located between the control assembly and the motor to generate a cooling airflow, part of which causes additional cooling of the control assembly
Data Source
Figure 1
AI summary
The present invention relates to a multistage centrifugal pump for pumping liquids with a cooled variable frequency drive, said pump being provided with a motor driving the rotation of a shaft which, after going through a leak-tight, rotary mechanical seal, is introduced into a leak-tight chamber in which the rotation of drive reels, attached in successive positions on said shaft, drives a liquid contained in said leak-tight chamber, increasing its pressure, from a liquid inlet to a liquid outlet, at least part of said control assembly being located on at least one part of said partition wall and in thermal contact with same for the cooling thereof, and housed between the partition wall and the motor..