Dual-Ring Stuffing Box With Split Pressure-Sealing Structure
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Solution Overview
Problem
Traditional stuffing boxes for pumping systems, particularly in fracturing pumps, are heavy, difficult to install, and prone to failures due to threaded interfaces, and require extensive material removal and forging, making them expensive and inefficient.
Innovation Solution
A dual-ring stuffing box configuration using a pressure ring made from wear-resistant stainless steel and an adjacent ring from alloy steel, joined by fasteners, with a face seal and cross-drilled weep holes, where the pressure ring is exposed to high pressure and the adjacent ring is not, reducing material costs and improving installation ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded stuffing boxes are used, then sealing function is provided, but weight is excessive and installation is difficult
Solution Approach 1:
The stuffing box is divided into two separate rings: a pressure-containing ring exposed to high pressure and an adjacent ring not exposed to high pressure. This segmentation allows each ring to be optimized independently, reducing overall weight while maintaining sealing functionality.
Solution Approach 2:
Different materials are used for different parts of the stuffing box based on local requirements. The pressure-containing ring uses wear-resistant stainless steel where high pressure and wear occur, while the adjacent ring uses less expensive alloy steel where high pressure is not present, optimizing both performance and weight.
2Reliability
If traditional integrated stuffing boxes are used, then sealing is provided, but material costs are high due to extensive material removal and forging
Solution Approach 1:
The integrated stuffing box is segmented into two separate rings that can be manufactured independently using simpler processes, avoiding extensive material removal and forging required for traditional integrated designs, thereby reducing manufacturing costs.
Solution Approach 2:
The two rings are joined together using fasteners to form the complete stuffing box assembly, combining the benefits of separate manufacturing (lower cost) with the functionality of an integrated sealing system.
3Ease of manufacture
If traditional threaded interfaces are used, then assembly is provided, but reliability is reduced due to prone to failures
Solution Approach 1:
The threaded interface is segmented into separate fastening elements that join the two rings, allowing for more reliable connections compared to traditional integrated threaded interfaces that are prone to failure under high pressure.
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 dual-ring configuration enhances sealing efficiency, reduces material costs, and simplifies installation by using less expensive materials and a secure locking mechanism, while maintaining the integrity of the sealing interface against high-pressure fracking fluids.
Implementation Method 1
a face seal positioned at an interface of the pressure ring and the fluid end face, the face seal containing pressurized fluid associated with the fluid end
Implementation Method 2
packing material positioned within at least a portion of the pressure ring bore
Data Source
AI summary
A system includes a fluid end having a fluid end face and a recess extending toward a base. The system also includes a pressure ring extending from the fluid end face, the pressure ring having a pressure ring bore diameter larger than a fluid end bore diameter. The system further includes an adjacent ring coupled to the fluid end, the pressure ring positioned between the adjacent ring and the base, wherein at least one fastener extends through an aperture of the adjacent ring to couple the adjacent ring to the fluid end. The system includes packing material positioned within at least a portion of the pressure ring bore, the packing material positioned such that axial movement toward the fluid end is blocked by the base.