Combined Pump Motor Eliminating Shaft Seal Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical submersible pumps (ESP) for well bore fluids have reliability issues due to their complex structure, high cost, and leakage problems caused by shaft seals, as well as installation challenges in curved well sections.
Innovation Solution
A combined pump and motor apparatus with a stator and diffusers that use an electromagnetic field to rotate an impeller with a circumferentially arranged array of permanent magnets, eliminating the need for a rotating shaft and reducing the number of components, thereby minimizing leakage and installation complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional ESP with rotating shaft and shaft seal is used, then the pump can transfer mechanical power from motor to impeller, but leakage occurs through the shaft seal causing motor failure
Solution Approach 1:
The patent replaces the traditional mechanical shaft and shaft seal system with an electromagnetic coupling system. The motor uses electromagnetic fields to directly drive the impeller without physical contact, eliminating the shaft seal that causes leakage. This substitution of mechanical transmission with electromagnetic interaction resolves the leakage problem while maintaining power transfer capability.
Solution Approach 2:
The invention extracts and removes the rotating shaft and shaft seal components from the traditional ESP system. By eliminating these components entirely and using electromagnetic fields for power transmission, the source of leakage is removed, preventing motor failure caused by fluid ingress.
2Stress or pressure
If a long motor assembly with multiple stages is used, then the pump can achieve high head pressure, but the assembly becomes difficult to install in curved well sections
Solution Approach 1:
The patent merges the motor and pump stages into a more compact integrated assembly. By reducing the overall length of the motor housing and optimizing the arrangement of electromagnetic components, the system achieves the required head pressure with a shorter, more flexible assembly that can navigate curved well sections more easily.
Solution Approach 2:
The invention introduces flexibility to the motor assembly through flexible couplings and adaptable mounting arrangements. This allows the rigid motor-pump stages to accommodate the curvature of deviated wellbores during installation, making the system more adaptable to different well geometries while maintaining high pressure capability.
3Reliability
If radial motor bearings and dielectric fluid are used, then the motor shaft can be supported and lubricated, but the assembly becomes more complex with additional components
Solution Approach 1:
The patent replaces the mechanical bearing and dielectric fluid lubrication system with magnetic bearings or direct electromagnetic support. The rotor is supported magnetically within the stator assembly, eliminating the need for radial bearings and dielectric fluid, thereby reducing component complexity while maintaining reliable support.
Solution Approach 2:
The electromagnetic system provides self-supporting functionality where the magnetic fields generated for motor operation also serve to support and position the rotor. This dual-function approach eliminates dedicated bearing components and lubrication systems, reducing overall assembly complexity.
4Temperature
If the motor is positioned above casing perforations or within a shroud, then cooling can be achieved, but the installation becomes more complex with additional positioning requirements
Solution Approach 1:
The pump system provides self-cooling by utilizing the produced fluid flowing through the pump stages to cool the motor assembly. The fluid naturally circulates through the motor housing and stator windings, providing cooling without requiring external cooling systems or specific positioning above perforations, thereby increasing installation flexibility.
Solution Approach 2:
The motor housing serves multiple functions: it provides structural support, contains the electromagnetic components, and acts as a heat sink for cooling. This multi-functional design eliminates the need for separate cooling systems or shrouds, allowing the motor to be installed in various well configurations without additional cooling infrastructure.
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
The solution results in a more reliable, cost-effective, and easier-to-install pumping system with reduced leakage and improved cooling efficiency, as well as the ability to operate effectively in curved well sections without the need for a pressure equalizer or external cooling.
Implementation Method 1
The stator has windings that create an electromagnetic field in the stator cavity when powered
Implementation Method 2
The array of magnets imparts rotation to the impeller in response to the electromagnetic field in the stator cavity
Data Source
AI summary
A combined pump and motor has a stator mounted for non-rotation in a housing. The stator has windings that create an electromagnetic field in the stator cavity when powered. An upper diffuser and a lower diffuser are mounted for non-rotation in the stator cavity. Annular clearances exist between the upper diffuser and the inner diameter of the stator and between the lower diffuser and the inner diameter of the stator. An impeller between the lower diffuser and the upper diffuser has an array of magnets circumferentially mounted around the impeller that impart rotation to the impeller in response to the electromagnetic field in the stator cavity. The array of magnets has at least one end portion extending into one of the upper and lower diffuser annular clearances.