ESP Pump Stage Sequential Engagement for Low-Torque Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric submersible pump (ESP) systems face issues with shaft damage and startup inertia due to solid buildup, leading to motor overload and potential shaft breakage during startup, especially when using direct on-line starters.
Innovation Solution
The implementation of a sequential engagement mechanism between pump stages using a transmission mechanism, allowing each pump section to start individually, reducing system inertia and torque requirements at startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If all pump stages are connected to the same shaft and start simultaneously, then the pump system can provide full head capacity, but the system inertia and torque requirements at startup increase significantly, leading to shaft damage or motor overload
Solution Approach 1:
The pump shaft is divided into multiple independent segments (first shaft segment, second shaft segment, third shaft segment) that can rotate independently. Each shaft segment connects to a corresponding pump stage, allowing staged engagement rather than simultaneous rotation of all stages. This segmentation reduces the moment of inertia at startup and decreases torque requirements on the motor and shaft connections.
Solution Approach 2:
The coupling mechanism is designed to engage shaft segments in a predetermined sequence during startup. The first shaft segment engages first, followed by the second, then the third segment as the motor accelerates. This preliminary sequencing of engagement allows each segment to reach operational speed gradually, preventing sudden torque shocks and reducing the risk of shaft breakage while still achieving full head capacity.
2Power
If all pump stages are connected to the same shaft and start simultaneously, then the pump system can provide full head capacity, but motor current spikes and overload occur during startup
Solution Approach 1:
The pump shaft is divided into multiple independent segments (first shaft segment, second shaft segment, third shaft segment) that can rotate independently. Each shaft segment connects to a corresponding pump stage, allowing staged engagement rather than simultaneous rotation of all stages. This segmentation reduces the moment of inertia at startup and decreases torque requirements on the motor and shaft connections.
Solution Approach 2:
The coupling mechanism enables periodic engagement of shaft segments during startup. Instead of all stages engaging simultaneously, they engage in sequential periods - first segment engages, then second, then third - allowing the motor to deliver current in manageable pulses rather than a single large spike, reducing overall energy stress on the motor.
3Ease of operation
If a direct on-line starter is used to start the ESP, then the startup is simple and fast, but the high torque applied can break the shaft due to solid buildup
Solution Approach 1:
The pump shaft is divided into multiple independent segments (first shaft segment, second shaft segment, third shaft segment) that can rotate independently. Each shaft segment connects to a corresponding pump stage, allowing staged engagement rather than simultaneous rotation of all stages. This segmentation reduces the moment of inertia at startup and decreases torque requirements on the motor and shaft connections.
Solution Approach 2:
The coupling mechanism is designed to engage shaft segments in a predetermined sequence during startup. The first shaft segment engages first, followed by the second, then the third segment as the motor accelerates. This preliminary sequencing of engagement allows each segment to reach operational speed gradually, preventing sudden torque shocks and reducing the risk of shaft breakage while still achieving full head capacity.
4Strength
If variable speed drive is used for rocking start procedure, then shaft damage risk is reduced, but the system complexity and cost increase
Solution Approach 1:
The pump shaft is divided into multiple independent segments (first shaft segment, second shaft segment, third shaft segment) that can rotate independently. Each shaft segment connects to a corresponding pump stage, allowing staged engagement rather than simultaneous rotation of all stages. This segmentation reduces the moment of inertia at startup and decreases torque requirements on the motor and shaft connections.
Solution Approach 2:
The coupling mechanism is designed to automatically engage and disengage shaft segments based on rotational speed conditions without requiring external control systems. The centrifugal or magnetic coupling engages when the motor reaches a certain speed and disengages when speed drops, providing self-regulating protection against shaft damage without adding complex control electronics or variable speed drive requirements.
Data Source
AI summary
A method for providing artificial lift with an electric submersible pump system includes providing an electric submersible pump system having a motor, a pump assembly, a seal assembly, and a shaft assembly extending along a central axis from the motor to the pump assembly. The pump assembly includes two or more pump sections and a coupling with a transmission mechanism is located between the two or more pump sections. The motor rotates a motor shaft segment of the shaft assembly that is in engagement with a first pump section and starts the first pump section. One of the transmission mechanisms is moved from a disengaged position to an engaged position where the coupling conveys the rotation of the motor shaft segment to the adjacent shaft segment and starts another of the two or more pump sections.