Offset Crankshaft Rod Assembly for Compact Fracturing Pumps
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Solution Overview
Problem
Hydraulic fracturing units face challenges in increasing pumping capacity due to physical dimension constraints, leading to potential premature wear or failure from increased shock and vibration, and proppant settling issues.
Innovation Solution
The implementation of a crankshaft and connecting rod assembly with a unique configuration, including offset crankpins and connecting rods, allows for increased pumping capacity without substantial length increase, reducing wear and vibration by offsetting plunger movements and distributing force more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pumping capacity of hydraulic fracturing units is increased, then the efficiency and effectiveness of fracturing operations improve, but the physical dimensions of the units exceed transportation size limits
Solution Approach 1:
The patent applies nesting by placing multiple connecting rods within a single crankshaft assembly. Specifically, multiple connecting rods are positioned side-by-side and connected to the same crankshaft, allowing the pump to achieve higher pumping capacity while maintaining a compact overall length that fits within transportation constraints.
Solution Approach 2:
The patent transitions from increasing capacity through length extension to achieving capacity through width utilization. By arranging multiple connecting rods in a side-by-side configuration rather than end-to-end, the design increases pumping capacity by utilizing the width dimension of the crankshaft assembly rather than extending the length.
2Productivity
If more powerful prime movers are used to increase pumping capacity, then the flow rate of fracturing fluid increases, but shock and vibration increase causing premature wear or failure
Solution Approach 1:
The patent applies counterbalancing by configuring multiple connecting rods and plungers to offset each other's shock and vibration. The reciprocating motions of multiple plungers are timed and positioned to create counteracting forces, reducing the net shock and vibration transmitted to the crankshaft and frame, thereby preventing premature wear and failure.
3Productivity
If the stroke length is increased to improve proppant suspension, then the pumping capacity increases, but the overall pump length exceeds transportation limits
Solution Approach 1:
The patent applies nesting by arranging multiple connecting rods with their respective plungers within a compact crankshaft assembly. This allows the effective stroke length to be optimized for proppant suspension while the overall pump length remains constrained by the compact nested arrangement of components.
Data Source
AI summary
Crankshaft and connecting rod assemblies for hydraulic fracturing pumps and related methods may enhance the flow of fracturing fluid into a wellhead during a high-pressure fracturing operation. The assemblies and methods may include a crankshaft having a crankpin between first and second journals. The crankpin may include first and second longitudinally spaced ridges at least partially extending circumferentially around the crankpin. The assemblies and methods further may include first and second connecting rods connected to the crankpin. The first connecting rod may include first and second crankpin connectors connected to the crankpin and at least partially defining therebetween a connecting rod clearance between and positioned to at least partially receive therein an end of a second connecting rod. The assemblies and methods also may include first and second rod clamps connected to the first crankpin connector, thereby to rotatably connect the first and second connecting rods to the crankpin.