Hydraulic Pump Packing Assembly With Staged Seal Pressure Compensation
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Solution Overview
Problem
Conventional hydraulic fracturing pump seal assemblies require mechanical compression to maintain seal engagement, leading to premature wear, fluid leakage, and frequent maintenance due to cyclic pressure loading, resulting in increased labor and replacement costs.
Innovation Solution
A novel packing assembly using multiple dynamic seals with staged pressure compensation, where clean lubrication fluid maintains seal engagement and reduces differential pressure across each seal, eliminating the need for a packing nut and minimizing wear through progressive pressure reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical compression is used to maintain seal engagement, then seal engagement is maintained, but seal wear increases and maintenance frequency increases
Solution Approach 1:
The packing assembly is divided into multiple discrete seal elements (first seal element, second seal element, third seal element) arranged in series along the plunger. Each seal element handles a portion of the sealing function, allowing them to wear independently and be replaced individually rather than requiring complete packing replacement. This segmentation distributes the mechanical stress and wear across multiple components.
Solution Approach 2:
The packing assembly incorporates a dynamic adjustment mechanism with a packing nut and adjustment member that allows the seal elements to be dynamically adjusted during operation. The system transitions from static mechanical compression to dynamic adjustment, where the packing nut can be rotated to move the adjustment member, thereby adjusting the compression force applied to each seal element based on operating conditions and wear levels.
2Reliability
If mechanical compression is used to maintain seal engagement, then seal engagement is maintained, but fluid leakage increases due to premature wear
Solution Approach 1:
The packing assembly includes a lubrication system with a lubricant reservoir and lubricant delivery mechanism that provides lubrication to the seal elements before wear occurs. The lubricant reduces friction and wear on the seal elements, preventing premature failure and fluid leakage. The system proactively applies protective lubrication rather than waiting for wear to occur.
Solution Approach 2:
The system changes the physical parameters of the sealing interface by introducing lubrication that alters the friction coefficient and contact conditions between the seal elements and plunger. This parameter change reduces wear rates and maintains seal effectiveness over extended periods, preventing fluid leakage.
3Reliability
If conventional packing assembly is used, then seal function is provided, but maintenance labor and replacement costs increase
Solution Approach 1:
The packing assembly is segmented into multiple replaceable seal elements and a modular adjustment mechanism. When wear occurs, individual seal elements can be replaced without replacing the entire packing assembly, and the adjustment member can be independently adjusted or replaced. This modular segmentation significantly reduces maintenance labor and material costs compared to conventional monolithic packing assemblies.
Solution Approach 2:
The packing assembly includes an integrated adjustment mechanism that allows operators to adjust seal compression and compensate for wear without requiring complete disassembly or professional service. The adjustment member can be operated through the fluid end housing to modify seal engagement, enabling field adjustments and extending service intervals between maintenance events.
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 novel packing assembly reduces seal stress and wear, minimizing leakage and maintenance needs, while maintaining constant seal engagement and lubrication across varying pressures, thus extending pump lifespan and reducing operational costs.
Implementation Method 1
A novel packing assembly using multiple dynamic seals with staged pressure compensation, where clean lubrication fluid maintains seal engagement and reduces differential pressure across each seal
Implementation Method 2
clean lubrication fluid maintains seal engagement and reduces differential pressure across each seal
Data Source
AI summary
A seal packing assembly for a hydraulic pump includes a plurality of annular dynamic seals disposed within annular grooves circumferentially defined in the annular bore, a packing gland circumferentially housing a section of the plunger, and a plurality of seal manifolds distributed and defined within the packing gland, each seal manifold defining a port at one end exposed to the pumping fluid and further defining a clean lubrication fluid inlet proximate to a second end, the fluid inlet coupled to a lube pump via a check valve, where the clean lubrication fluid housed in the seal manifolds is maintained at a constant pressure. Each seal manifold includes a piston disposed within the seal manifold having a first end configured with a first surface area to interface with the pumping fluid and a second end configured with a second surface area to interface with the clean lubrication fluid, and a fluid port configured to provide fluid communication between the seal manifold and the annular grooves of the annular dynamic seals.