Camming Scraper Ring Assembly for Abrasive Pump Sealing
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Solution Overview
Problem
Conventional sealing arrangements in high pressure reciprocating pumps are ineffective in maintaining seals against abrasive materials, leading to premature wear and reduced lifespan, especially in high-pressure and high-debris environments like fracking operations.
Innovation Solution
An annular scraper ring assembly with multiple rings of varying resiliencies, featuring a camming mechanism to enhance sealing forces and a tapered design to prevent debris accumulation, is integrated into the packing arrangement to improve sealing efficacy and extend component lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing arrangements are used in high pressure reciprocating pumps, then the pump can operate, but the sealing effectiveness deteriorates rapidly due to abrasive materials causing premature wear
Solution Approach 1:
The packing arrangement is divided into multiple sequential rings with distinct functions: scraper rings (resilient material) to remove debris, junk rings (stiffer material) to trap abrasive materials, and pressure rings to maintain sealing force. This segmentation allows each ring to specialize in a specific protective function, preventing abrasive materials from reaching and damaging the plunger and downstream components.
Solution Approach 2:
Different rings are made from materials with specifically tailored properties for their local function: resilient elastomeric material for scraper rings to conform to the plunger and scrape debris, stiffer material for junk rings to trap abrasives, and appropriate materials for pressure rings to maintain sealing force. Each material is optimized for its specific role in the packing arrangement.
2Reliability
If resilient material is used for the first ring to form a seal against the plunger, then sealing effectiveness improves, but the ring wears prematurely due to exposure to abrasive materials
Solution Approach 1:
The scraper ring (first ring) performs preliminary action by scraping abrasive materials and debris off the plunger surface before the fluid reaches downstream components. This preliminary cleaning action protects downstream components from wear and damage, extending their lifespan even though the scraper ring itself may require replacement.
Solution Approach 2:
The scraper ring is designed as a sacrificial component made from resilient material that can be easily replaced. It performs its function of scraping and protecting downstream components, then can be replaced when worn, while the more expensive downstream components are protected from similar wear.
3Reliability
If multiple rings with varying resiliencies are used in the scraper ring assembly, then debris control and sealing forces improve, but device complexity increases
Solution Approach 1:
Each ring in the assembly serves multiple functions: the scraper ring both seals against the plunger and scrapes debris; the junk ring both traps abrasive materials and maintains packing structure; the pressure ring both applies sealing force and distributes load. This multi-functionality justifies the increased complexity by providing comprehensive protection and sealing in a single integrated assembly.
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 scraper ring assembly significantly enhances sealing forces and debris control, reducing wear and extending the lifespan of the packing arrangement by effectively scraping off debris and preventing 'nibbling' phenomena, thus minimizing maintenance downtime in harsh drilling conditions.
Implementation Method 1
The first ring includes an upstream face and an inner surface and is formed from a resilient material configured to form a seal against a plunger
Implementation Method 2
The second ring defines a camming surface configured to engage the upstream face of the first ring and cam the inner surface of the first ring inwards when the first ring is compressed against the second ring
Data Source
AI summary
An annular scraper ring assembly for a packing arrangement is disclosed. The annular scraper ring assembly can form a seal with a plunger included in a fluid end of a reciprocating pump and includes two or more rings, including a first ring and a second ring. The first ring is formed from a resilient material configured to form a seal against a plunger included in a fluid end of a reciprocating pump and includes an upstream face and an inner surface. The second ring defines a caroming surface configured to engage the upstream face of the first ring and cam the inner surface inwards when the first ring is compressed against the second ring.