Pumpjack Inertia Capacitor Flywheel Kinetic Energy Storage
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Solution Overview
Problem
Oil well pumpjacks face inefficiencies due to prime movers operating inefficiently under dynamic torque conditions, leading to cyclic stress on sucker rod strings and reduced service life, as existing flywheels are inadequate in storing kinetic energy to maintain constant speed and minimize negative torque effects.
Innovation Solution
The Pumpjack Inertia Capacitor (PIC) employs a unique configuration of high kinetic energy flywheels, shafts, bearings, and gears to maximize energy storage, smoothing power and torque transfer between the prime mover and gearbox, enabling near constant speed operation and reducing feedback torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If prior art flywheels are used in pumpjacks, then the device complexity is reduced, but the kinetic energy storage capacity is insufficient to maintain constant speed and minimize dynamic torque effects
Solution Approach 1:
The flywheel system is divided into multiple separate flywheels (typically three) rather than using a single large flywheel. Each flywheel operates at the prime mover's rotational speed and is connected through a differential mechanism, allowing the system to achieve high kinetic energy storage capacity while keeping individual flywheel sizes manageable and the overall configuration less complex
Solution Approach 2:
A differential mechanism serves as an intermediary device that connects the multiple flywheels to the prime mover and load. This differential allows the flywheels to rotate at the prime mover's speed while their combined kinetic energy smoothing effect operates at the load side, effectively decoupling the speed requirements and enabling constant speed operation without complex direct connections
2Adaptability or versatility
If the prime mover operates under dynamic torque conditions to match pump unit torque, then the adaptability to pumping cycle variations is improved, but the prime mover efficiency deteriorates due to continuous switching between motor and generator modes
Solution Approach 1:
The kinetic energy smoothing function is extracted from the prime mover and placed into the flywheel system. The flywheels absorb and release kinetic energy to smooth out torque variations, allowing the prime mover to operate at constant speed and constant power without continuously switching between motor and generator modes, thus eliminating the efficiency losses associated with these transitions
Solution Approach 2:
The flywheels store kinetic energy in advance during periods of low torque demand and release it during periods of high torque demand. This preliminary energy storage and release action smooths the torque delivered to the pump unit, maintaining adaptability to pumping cycle variations while allowing the prime mover to operate efficiently at constant conditions
3Ease of manufacture
If prior art flywheels are used with lower rotational speeds, then the device simplicity is maintained, but the kinetic energy storage capacity is substantially reduced compared to high-speed flywheels
Solution Approach 1:
The system dynamically utilizes multiple flywheels rotating at the prime mover's operational speed rather than a single static low-speed flywheel. The differential mechanism enables the flywheels to operate dynamically at higher speeds where kinetic energy storage capacity (proportional to the square of rotational speed) is substantially greater, while the overall system remains manufacturable using standard prime mover speed components
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 configuration enhances mechanical efficiency and extends the service life of oil well pumpjacks by maintaining near constant speed and power, reducing shock loads, and allowing the use of less expensive prime movers.
Implementation Method 1
A flywheel, also known as an inertia capacitor, is a rotating mechanical device used to store rotational energy or kinetic energy. Flywheels have a significant rotational mass moment of inertia and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed.
Implementation Method 2
Flywheels have a significant rotational mass moment of inertia and thus resist changes in rotational speed. The rotational mass moment of inertia is the mass property of a rigid body that determines the torque needed for a desired angular acceleration about an axis of rotation.
Implementation Method 3
Energy is transferred to a flywheel by applying torque to it, thereby increasing its rotational speed and hence its stored energy. Conversely, a flywheel releases stored energy by applying torque to a mechanical load, thereby decreasing the flywheel's rotational speed.
Data Source
AI summary
A kinetic energy storage device, a pumpjack inertia capacitor (PIC), for use with an oil well pumpjack, the PIC includes a primary shaft assembly to transfer power and torque between a prime mover of the oil well pumpjack, a flywheel assembly having one or more flywheels, and an output assembly, the one or more flywheels absorb and then transfer torque to an oil well pumping unit to enable the oil well pumping unit to operate at a near constant speed; and the one or more flywheels enable the prime mover to operate at a near constant speed and a near constant power.