Fluid End Plug With Bore Clearance for Low-Torque Assembly
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Solution Overview
Problem
The assembly and disassembly of discharge and suction plugs in high-pressure fracturing pumps are difficult due to small clearances between the plug and bore, requiring high torque and force, often necessitating large wrenches and slide hammers.
Innovation Solution
The plugs are designed with variable diameters, minimizing the axial length of the sealing section and providing diametral clearances to allow rotation about a perpendicular axis, reducing friction and assembly/disassembly effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plug is designed with full engagement to the bore walls, then the sealing reliability is improved, but the assembly and disassembly difficulty increases
Solution Approach 1:
The plug is divided into two distinct zones: a first zone with full bore wall engagement for sealing, and a second zone with diametral clearance for ease of assembly. This segmentation allows different portions of the plug to serve different functions - the engaged portion ensures reliability while the clearance portion facilitates operation.
Solution Approach 2:
Different regions of the plug have different diameters to optimize local functions. The first zone has a diameter matching the bore for sealing engagement, while the second zone has a reduced diameter creating diametral clearance. This local variation in geometry resolves the contradiction between sealing reliability and assembly ease.
2Ease of manufacture
If the plug has uniform diameter along its length, then the manufacturing simplicity is improved, but the assembly torque requirement increases
Solution Approach 1:
The plug features variable diameter along its length rather than uniform diameter. The first zone has a larger diameter for sealing engagement while the second zone has a reduced diameter. This local variation reduces the contact area and friction during assembly, lowering torque requirements while maintaining sealing effectiveness in the engaged zone.
3Reliability
If the sealing section axial length is increased, then the sealing reliability is improved, but the friction and assembly force increase
Solution Approach 1:
The plug concentrates the sealing function in a specific zone (first zone) with appropriate axial length, while the second zone provides clearance to reduce overall friction. This localized sealing approach ensures reliability where needed without requiring the entire plug length to be engaged, thereby reducing total assembly force requirements.
Solution Approach 2:
The plug is segmented into a sealing zone and a clearance zone. The sealing zone (first zone) provides the necessary axial length for reliable sealing, while the clearance zone (second zone) reduces overall friction and assembly force. This segmentation allows optimization of sealing reliability without proportionally increasing assembly force.
Data Source
AI summary
A closure for a fluid end having a middle sealing section which engages a seal. The sealing section either has a larger outer diameter than adjacent sections or contacts a bore with a smaller inner diameter than adjacent sections. In either case, the clearance formed on either side of the sealing section reduces friction and allows the closure to be rocked back and forth to insert and remove the closure from the fluid end bore.