Thrust Box Seal Mounting and Lubrication Cooling for Submersible Pumps
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Solution Overview
Problem
Existing horizontally mounted submersible pump systems face issues with thrust box design, including heat buildup and lubricant failure due to lack of circulation and cooling, stress cracks from groove-cutting in shafts, and increased downtime due to the need for multiple shafts and complex alignment procedures when relocating or replacing components.
Innovation Solution
The improved thrust box features seals mounted directly to the casing, a completely flooded lubricant case with vacuum pressure and heat exchanger for cooling, equalizing thrust bearings, and a design allowing the thrust box to be removed without disassembling the motor or pump, along with a heat sensor and load sensor for monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thrust box uses traditional seals held by clip rings in shaft grooves, then the seal structure is simple, but stress cracks are introduced in the shaft and seal life is reduced
Solution Approach 1:
The seal mounting structure is extracted from the shaft and relocated to the thrust box casing. The seals are now held by retaining rings mounted in grooves in the thrust box casing rather than in the shaft, removing the harmful grooves from the shaft while maintaining seal functionality.
Solution Approach 2:
The thrust box casing serves as an intermediary structure that holds the seals. Instead of the shaft directly holding seals (which causes stress cracks), the casing acts as a mediator that supports the seals without compromising shaft integrity.
2Reliability
If the thrust box lacks lubricant circulation and cooling, then the structure is simpler, but heat builds up and lubricant fails quickly
Solution Approach 1:
The lubrication system provides continuous circulation of lubricant through the thrust box casing interior. A pump continuously moves lubricant through the system, and a heat exchanger continuously removes heat, ensuring ongoing protection and cooling rather than static lubrication.
Solution Approach 2:
A hydraulic lubrication system is implemented where lubricant is pumped through the thrust box casing interior and circulated continuously. The system uses fluid dynamics to deliver lubricant under pressure to bearing surfaces and uses a heat exchanger to thermally manage the lubricant.
3Reliability
If different seals are used for different pressures, then sealing performance is optimized, but multiple shafts must be stocked or custom made
Solution Approach 1:
The thrust box casing is designed with a universal seal mounting structure that can accommodate different seal lengths and types. The adjustable positioning of seal retaining rings allows the same thrust box and shaft to work with multiple seal configurations for different pressure applications.
Solution Approach 2:
The seal mounting system is made dynamic and adjustable rather than fixed. The retaining rings can be positioned at different locations in the thrust box casing to accommodate varying seal lengths, allowing the system to adapt to different operating conditions without changing the shaft.
4Ease of operation
If the thrust box is integrated with motor and pump, then the assembly is compact, but the thrust box cannot be replaced without removing and realigning the motor
Solution Approach 1:
The thrust box is segmented as a separate, independently replaceable component from the motor and pump assembly. The mounting brackets and coupling design allow the thrust box to be detached and replaced without disturbing the motor or pump, enabling rapid maintenance.
Solution Approach 2:
The motor and pump are pre-aligned and permanently mounted to the skid, while the thrust box is designed with preliminary mounting features that allow quick attachment and detachment. This preliminary setup eliminates the need for realignment during thrust box replacement.
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 design enhances the service life of the thrust box and seals, reduces downtime by allowing the thrust box to be replaced without realigning the motor, and provides real-time monitoring for maintenance, thus minimizing operational disruptions and costs.
Implementation Method 1
The lubricant is pumped out of the case and through an oil filter and a heat exchanger to remove excess heat
Implementation Method 2
The longevity of the seals is also aided by the fact that the lubricant is removed from the case under a vacuum pressure rather than being forced under positive pressure through the case
Data Source
AI summary
A thrust chamber using a single thrust bearing and having seals secured to the thrust chamber case. Also a skid for a horizontally mounted submersible pump, thrust chamber and drive mechanism. The skid having a thrust chamber mounting bracket which provides positive mounting locations thus allowing for the change out of the thrust chamber without removing the drive mechanism.