Submersible Pump Axial Thrust Balance Piston
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Solution Overview
Problem
Submersible well pumps face challenges in balancing axial thrusts, leading to increased equipment needs and failure rates due to mechanical contact between the motor and pump shaft, which complicates installation and operation.
Innovation Solution
The implementation of a downhole-type pump with a fluid rotor, fluid stator, and balance piston that uses dynamic seals and a magnetic coupling to transfer rotary motion, reducing the reliance on thrust bearings and eliminating mechanical contact, thereby balancing axial thrusts and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If thrust bearings are used to absorb axial thrust load in the protector, then the axial thrust is supported, but the mechanical contact increases equipment failure rates and complicates the structure
Solution Approach 1:
The patent removes the protector section containing thrust bearings from the ESP system, extracting the source of mechanical contact and failure. The axial thrust is instead absorbed by the pump assembly itself through the balance piston mechanism, eliminating the need for thrust bearings in the protector and thereby reducing equipment failure rates.
Solution Approach 2:
The patent replaces the mechanical thrust bearing system with a hydraulic balance piston system. Pressurized fluid acts on the balance piston to generate a counteracting force that balances the axial thrust, substituting mechanical contact with fluid pressure transmission and eliminating wear-associated failures.
2Reliability
If a magnetic coupling is used to transfer rotary motion, then mechanical contact is eliminated, but the device complexity increases
Solution Approach 1:
The patent replaces the mechanical shaft coupling system with a magnetic coupling system that transfers rotary motion through magnetic fields without physical contact. This eliminates wear and mechanical failure points in the coupling mechanism, improving reliability despite the added complexity of magnetic field management.
3Reliability
If the motor is encapsulated to prevent contact with production fluids, then reliability is improved, but the heat dissipation capability is reduced
Solution Approach 1:
The patent uses a thin-walled encapsulation around the motor that provides fluid isolation while maintaining thermal conductivity. The encapsulation acts as a flexible barrier that protects the motor from production fluids while allowing heat to dissipate through the wall material, balancing protection and thermal management.
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 solution effectively reduces axial thrusts in submersible well pumps, decreases equipment failure rates, simplifies installation, and maintains volumetric efficiency, while encapsulating the motor to prevent contact with production fluids.
Implementation Method 1
a magnetic coupling to transfer rotary motion
Implementation Method 2
A portion of the pressurized and displaced fluid is directed to an opposite side of the rotor. A second axial thrust, which is created by the portion of the pressurized and displaced fluid, counters the first axial thrust.
Data Source
AI summary
A fluid rotor and a fluid stator. The fluid stator surrounds the fluid rotor. The fluid stator has an intake end and a discharge end. The fluid stator is shaped to be inserted into a wellbore. A shaft passes through a rotational axis of the fluid rotor. The shaft is attached to the fluid rotor to rotate in union with the fluid rotor. The shaft defines a central fluid passage that extends from the intake end of the fluid rotor to the discharge end of the fluid rotor. A balance piston surrounds the shaft. The balance piston extends from an outer surface of the shaft to an inner surface of the fluid stator. The balance piston is positioned at the intake end.