Dual-Rotation ESP Pump Assembly for Shaft Backspin Prevention
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Solution Overview
Problem
Existing ESP systems face issues with rotation of the motor shaft when not in operation, leading to potential electrical hazards and reduced system life due to erosion and abrasive wear, especially in unconventional wells with varying fluid rates.
Innovation Solution
Implementing a combination of centrifugal pumps designed for both clockwise and counterclockwise rotation, with one pump operating efficiently in each direction, to prevent motor shaft rotation when not powered and extend the hydraulic operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single centrifugal pump is designed for CW rotation, then it operates efficiently in CW direction, but it cannot prevent motor shaft rotation when not powered and has limited hydraulic operating range
Solution Approach 1:
The patent combines two centrifugal pumps with opposite rotation directions (CW and CCW) into a single integrated pump assembly that shares common structural components. This merging allows the system to maintain high efficiency in the primary CW operating mode while gaining the ability to operate in CCW direction, thereby extending the hydraulic operating range without sacrificing productivity
Solution Approach 2:
The dual-direction pump assembly is designed to perform multiple functions: it can efficiently pump fluid in CW direction during normal operation, efficiently pump fluid in CCW direction when needed, and prevent motor shaft rotation when the ESP is not in operation. The shared structural components enable this multi-functionality while reducing overall system complexity compared to having separate pump systems
2Use of energy by moving object
If fluid flows through the pump when not powered, then the pump rotates and generates electrical energy, but this creates electrical hazards for personnel
Solution Approach 1:
The patent applies preliminary anti-action by designing the CCW pump to counteract the rotational force generated by fluid flow through the CW pump. When the ESP is not powered, the CCW pump creates an opposing torque that prevents the motor shaft from rotating, thereby preventing the motor from acting as a generator and eliminating the electrical hazard before it can occur
Solution Approach 2:
The invention converts the potential harmful effect of fluid-induced rotation into a beneficial feature. The CCW pump, which would normally be considered redundant or inefficient, is utilized to create counter-torque that prevents unwanted rotation. The structural components of the CCW pump are leveraged to provide a safety function, transforming what could be wasted resources into a protective mechanism
3Adaptability or versatility
If the pump operates outside its hydraulic operating range, then it can handle varying fluid rates, but this causes excessive impeller thrust and destroys pump internals
Solution Approach 1:
The patent implements dynamics by enabling the pump system to change its operational characteristics based on flow conditions. The dual-direction design allows the system to switch between CW and CCW operation modes, effectively changing the hydraulic performance characteristics to match different operating conditions. This dynamic adaptability prevents operation in damaging regimes by providing alternative flow paths and thrust distribution patterns
4Object-affected harmful factors
If motor shaft rotation is prevented using mechanical braking, then electrical hazards are reduced, but this increases device complexity and reduces system life due to wear
Solution Approach 1:
The patent applies self-service by using the CCW pump's hydraulic structure to automatically provide counter-torque that prevents motor shaft rotation. The system utilizes its own internal hydraulic forces and structural components rather than requiring external braking mechanisms. The CCW pump's impeller and casing work together with the CW pump to create the necessary opposing forces, making the system self-regulating and eliminating the need for separate braking 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
Prevents motor shaft rotation when not powered, reducing electrical hazards and extending system life by balancing wear patterns and expanding the operating range.
Implementation Method 1
power (usually three-phase AC power) is provided to the windings of the motor's stator, causing the stator to generate rotating magnetic fields in the stator. These rotating magnetic fields induce currents and corresponding magnetic fields in a rotor, causing the rotor and the motor shaft to rotate
Implementation Method 2
The rotor of the permanent magnet motor, however, has a set of permanent magnets which cause the rotor to rotate in the rotating magnetic fields generated by the stator
Implementation Method 3
If fluid is caused to flow through the pump, this will cause the pump to rotate, which will in turn cause the motor to rotate and generate an AC voltage
Data Source
AI summary
An ESP pump includes a first centrifugal pump having a first vane design to operate in a clockwise direction, and a second centrifugal pump having a second vane design to operate in a counterclockwise direction, with a submersible induction or permanent magnet motor for driving the first and second centrifugal pumps. The first and second centrifugal pumps being connected to a common shaft.