Reciprocating-Rod Seal With Segmented Lips
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Solution Overview
Problem
In offshore drilling and industrial applications, existing reciprocating-rod seals in mudpumps face challenges with accessibility and durability, particularly in high-pressure environments, where convenient replacement and effective sealing are crucial to prevent fluid leakage and debris accumulation.
Innovation Solution
A one-piece rigid support and elastomeric body seal design that forms a sealing lip to prevent fluid escape and a wiping lip to remove debris, bonded to withstand heat and pressure, with a cylindrical retaining wall and flange/anchor structure for enhanced installation and bonding, allowing for easy access and potential reinforcement for increased durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional reciprocating-rod seals are used in high-pressure mudpump environments, then sealing function is provided, but accessibility for installation and replacement becomes difficult
Solution Approach 1:
The seal assembly is segmented into distinct functional components: a retainer assembly with cylindrical retainer and flat retainer, an elastomeric body with sealing lip and wiping lip, and optional buffer rings. This segmentation allows each component to be optimized independently while maintaining overall sealing reliability, and facilitates easier installation and replacement of the entire seal assembly as a modular unit.
Solution Approach 2:
The elastomeric body performs multiple functions simultaneously: it provides the primary sealing function through the sealing lip, removes debris through the wiping lip, and can accommodate buffer rings for additional protection. The retainer assembly provides both structural support and positioning functions. This multi-functionality reduces the number of separate components needed and simplifies installation.
2Reliability
If multiple sealing components (buffer rings, stronger seals) are added to ensure sealing reliability, then sealing performance improves, but device complexity increases
Solution Approach 1:
The invention merges the sealing function, wiping function, and structural support into a single integrated elastomeric body and retainer assembly. The elastomeric body contains both the sealing lip and wiping lip as integrated features, eliminating the need for separate wiping components. Buffer rings can be integrated within the elastomeric body structure rather than being separate external components.
Solution Approach 2:
The elastomeric body is designed as a universal component that simultaneously provides sealing, wiping, and structural functions. The retainer assembly serves both as a mounting structure and as a positioning mechanism. This multi-functionality allows reliable sealing with fewer total components compared to traditional designs that use separate buffer rings, wear rings, and sealing elements.
3Power
If the seal operates in high-pressure environments with reciprocating motion, then pumping function is achieved, but durability and resistance to heat and pressure deteriorate
Solution Approach 1:
The seal assembly uses composite construction with a rigid retainer assembly (metal or rigid plastic) providing structural strength to withstand high pressure, and a flexible elastomeric body providing sealing compliance and durability. The elastomeric material is selected for its resistance to heat, pressure, and chemical degradation from mud slurry. This composite approach allows the seal to withstand high-pressure pumping conditions while maintaining durability.
Solution Approach 2:
The elastomeric body is designed with specific material properties and geometric parameters optimized for high-pressure reciprocating motion. The cross-sectional shape, wall thickness, and lip geometry are engineered to distribute pressure loads and accommodate thermal expansion. The material composition can be adjusted to withstand specific temperature and pressure ranges required for different pumping applications.
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 seal effectively prevents fluid leakage and debris accumulation during reciprocal motion, ensuring reliable operation in high-pressure conditions and simplifying installation, inspection, and replacement, potentially serving as the primary seal without additional buffer rings or stronger seals.
Implementation Method 1
a one-piece rigid support and a one-piece elastomeric body bonded to the rigid support
Implementation Method 2
elastomeric body bonded to the rigid support
Implementation Method 3
The elastomeric body also forms a wiping lip, that removes dirt, dust and other debris from the rod during return strokes
Data Source
AI summary
A reciprocating-rod seal (10) comprising a one-piece rigid support (20) and a one-piece elastomeric body (30) bonded to the rigid support (20). A notch (40) separates an ID fluidside portion (41) of the elastomeric body (30) from an OD fluidside portion (42) of the elastomeric body (30), and the ID fluidside portion (41) forms a sealing lip (43). A groove (50) separates an ID airside portion (51) of the elastomeric body (30) from an OD airside portion (52) of the elastomeric body (30), and the ID airside portion (51) forms a wiping lip (53). The sealing lip (43) prevents fluid escape during forward and return strokes of a reciprocating rod, and the wiping lip (53) removes dirt, dust, or other debris from the rod during return strokes. The seal (10) can serve as the primary seal for a mudpump pony rod and/or a mudpump plunger rod.