Torsional Coupling for Misaligned Fracturing Pump Drives
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Solution Overview
Problem
U-joint shafts used in hydraulic fracturing systems introduce inefficiencies, losing up to 10% of energy and requiring a minimum 3-degree offset, which complicates setup in space-constrained environments like trailers or trucks.
Innovation Solution
A torsional coupling system that connects the electric motor shaft to the pump shaft, allowing for radial, axial, or angular misalignment while maintaining torque transmission, using elastomeric inserts for vibration absorption and a retainer cap to prevent debris ingress, with optional tapered central bore for improved alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a U-joint shaft is used to connect motor and pump shafts, then misalignment between motor and equipment is compensated, but energy loss increases by up to 10% or more
Solution Approach 1:
A torsional coupling device is introduced as an intermediary component between the motor shaft and pump shaft. This coupling includes flexible elements that mediate the connection, allowing misalignment compensation while maintaining efficient torque transmission. The flexible coupling elements act as mediators that accommodate radial, axial, and angular misalignments without the significant energy losses associated with U-joint shafts.
Solution Approach 2:
The invention changes the physical parameters of the connection system by using flexible coupling elements with specific material properties and geometric configurations. These parameter changes enable the coupling to accommodate misalignments (radial, axial, angular) while maintaining high torque transmission efficiency, contrasting with the U-joint shaft that loses up to 10% or more energy.
2Adaptability or versatility
If a U-joint shaft is used to allow misalignment, then a minimum of 3 degrees of offset is required, but this leads to longer shaft length and greater separation between motor and equipment
Solution Approach 1:
The torsional coupling serves as an intermediary that eliminates the need for long shafts required by U-joint systems. By incorporating flexible elements directly at the connection point between motor and pump, the coupling accommodates misalignments without requiring extended shaft lengths, thereby reducing the separation distance between motor and equipment in space-constrained environments.
Solution Approach 2:
The invention changes the geometric parameters of the connection system by using compact flexible coupling elements instead of long shafts. The coupling elements are designed with specific flexibility parameters that allow 3 degrees of offset tolerance while maintaining a compact form factor, thus reducing both shaft length and overall separation distance.
3Ease of operation
If U-joint shaft is used for mechanical communication, then motor and equipment can be connected with offset, but setup space requirements increase due to longer shaft
Solution Approach 1:
The torsional coupling acts as a compact intermediary device that provides setup flexibility without increasing space requirements. By placing the flexible coupling elements directly at the motor-pump interface, the system achieves ease of operation for misaligned installations while maintaining a compact footprint suitable for trailer or truck body mounting where space is limited.
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 torsional coupling reduces energy loss to less than 1%, allows for a shorter driveshaft, and simplifies setup in limited spaces, enhancing efficiency and mobility of hydraulic fracturing equipment.
Implementation Method 1
elastomeric inserts positioned between the pump coupling claws or the motor coupling claws, respectively, to provide a buffer therebetween and to absorb movement and vibration in the torsional coupling
Data Source
AI summary
A system for hydraulically fracturing an underground formation in an oil or gas well, including a pump for pumping hydraulic fracturing fluid into the wellbore, the pump having a pump shaft, and an electric motor with a motor shaft mechanically attached to the pump to drive the pump. The system further includes a torsional coupling connecting the motor shaft to the pump shaft. The torsional coupling includes a motor component fixedly attached to the motor shaft and having motor coupling claws extending outwardly away from the motor shaft, and a pump component fixedly attached to the pump shaft of the pump and having pump coupling claws extending outwardly away from the pump shaft. The motor coupling claws engage with the pump coupling claws so that when the motor shaft and motor component rotate, such rotation causes the pump component and the pump shaft to rotate, thereby driving the pump.