Frac Pump Sealed Nut Assembly Alignment
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Solution Overview
Problem
Conventional nut and plug assemblies in fluid ends of high-pressure pumps used in hydraulic fracturing are prone to misalignment, damage, and leakage due to high pressures and harsh contaminants, requiring complex and labor-intensive installation and maintenance processes.
Innovation Solution
A combined nut and plug assembly where the threaded nut portion engages the fluid end threads before the plug, ensuring proper alignment and simplifying installation and removal, while incorporating multiple seals to prevent leakage and extend longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a separate nut and plug assembly is used in conventional fluid ends, then the plug can be press fit into the bore, but misalignment and damage occur due to difficulty in applying concentric force during installation
Solution Approach 1:
The patent combines the nut and plug into a single integrated assembly where the nut is formed as one piece with the plug. This merging eliminates the need for separate installation steps, ensures automatic alignment when threading the assembly, and prevents misalignment issues that occur with separate components. The integrated design allows the plug to be precisely positioned while the nut provides both sealing and retention functions.
2Ease of repair
If a separate nut and plug assembly is used, then the plug can be press fit into the bore, but damage occurs when hammering against the plug during removal
Solution Approach 1:
By integrating the nut and plug into a single assembly, the patent enables removal of both components together by simply unscrewing the nut. This eliminates the need to hammer against the plug to break it loose from the bore, thereby preventing damage to the plug and the bore. The combined assembly allows for clean, controlled removal without impact forces.
3Reliability
If a single seal is used in conventional plugs, then the structure is simpler, but the seal wears quickly and leaks due to exposure to harsh contaminants and high pressure
Solution Approach 1:
The patent implements a dual-seal configuration where two seals are positioned at different locations within the plug assembly. The first seal is positioned to seal against the bore, while the second seal provides additional sealing protection. This local enhancement of sealing quality at critical positions protects against the harsh contaminants and high pressures without requiring a complete redesign of the entire assembly.
4Productivity
If conventional separate nut and plug assemblies are used, then installation is possible, but labor costs and service time increase due to complex installation and removal processes
Solution Approach 1:
The integrated nut-plug assembly reduces maintenance operations to a single threaded connection that can be quickly installed and removed. Both the nut and plug are installed or removed together as one unit, eliminating multiple steps such as separate plug insertion, nut threading, and plug extraction. This significantly reduces labor time and increases maintenance productivity.
5Strength
If the plug is press fit into the bore, then the plug can be securely positioned, but the installation process requires high concentric force that is difficult to apply
Solution Approach 1:
The patent replaces the press-fit retention method with a threaded connection system where the nut is integrally formed with the plug. The threaded engagement provides secure retention through rotational locking, which is easier to apply than concentric press-fit forces. The threading mechanism naturally guides the assembly into proper alignment while providing progressive engagement that secures the plug firmly in position.
Data Source
AI summary
A sealed nut assembly includes a nut portion and a plug portion integrally formed together as a single unit. The nut assembly is configured to seal a bore hole in a fluid end and prevent leakage of working fluid therein. The assembly includes a nut portion and a plug portion. The nut portion and plug portion are inserted and removed together. The nut portion engages the fluid end prior to the setting of the plug portion. A seal groove is included in the plug portion to locate one or more seals. The contact surface between the nut assembly and the fluid end is tapered.