Plunger Pump Hydraulic End Sealing for High-Pressure Cyclic Loading
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Solution Overview
Problem
Conventional plunger pumps face challenges in maintaining continuous operation with high pressure and large displacement due to sealing failures caused by cyclic loading, leading to premature wear and potential hydraulic cutting of the valve housing, which reduces the service life and poses safety risks.
Innovation Solution
A new hydraulic end assembly structure replaces the O-ring or D-ring sealing form with a suction packing seal assembly comprising a support ring, soft packing, hard packing, and packing junk ring, which provides enhanced sealability and resistance to high pressure and fluid flushing, reducing abrasion and extending the service life of the suction gland and valve housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If O-ring or D-ring sealing is used in the hydraulic end assembly, then the structure is simple and easy to manufacture, but the sealing reliability deteriorates under high pressure and large displacement due to cyclic loading causing deformation and indentations
Solution Approach 1:
The sealing structure is divided into multiple functional components: support ring for structural support, soft packing for sealing, hard packing for wear resistance, and junk ring for debris collection. This segmentation allows each component to perform its specific function optimally, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The invention uses composite sealing structure combining soft packing material (for elasticity and sealing) and hard packing material (for wear resistance and structural stability). This composite approach maintains sealing effectiveness under high pressure and cyclic loading while preserving ease of manufacture through modular assembly.
2Device complexity
If O-ring or D-ring sealing is used, then the device complexity is low, but the service life of valve housing deteriorates due to abrasion and hydraulic cutting
Solution Approach 1:
Different regions of the sealing assembly have different material properties: the support ring provides structural rigidity at the outer region, while the soft packing provides sealing compliance at the contact region, and hard packing provides wear resistance at the friction region. This local quality differentiation extends valve housing service life without significantly increasing overall device complexity.
Solution Approach 2:
The packing assembly acts as an intermediary between the suction gland and valve housing, absorbing wear and preventing direct metal-to-metal contact. The junk ring serves as an intermediary to collect debris before it can cause hydraulic cutting, thereby extending service life while maintaining relatively simple device architecture.
3Reliability
If conventional sealing rings are used under high pressure and large displacement, then the initial sealing is adequate, but the sealing performance deteriorates over time due to cyclic loading causing deformation and recovery of sealing rings
Solution Approach 1:
The sealing system incorporates dynamic elements: soft packing that can elastically deform to maintain sealing contact under pressure cycles, and the junk ring that can move to accommodate sealing ring deformation. This dynamic response maintains sealing performance throughout continuous operation rather than degrading over time.
Solution Approach 2:
The support ring and hard packing are installed beforehand to provide structural cushioning and prevent excessive deformation of the soft packing during operation. This pre-positioned cushioning structure protects the sealing system from the full impact of cyclic loading, maintaining sealing reliability throughout the intended service duration.
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 suction packing seal assembly effectively meets the sealing requirements under high pressure and large displacement conditions, reducing wear and significantly prolonging the service life of the hydraulic end assembly components, ensuring continuous operation of the plunger pump.
Implementation Method 1
the suction gland is connected to the valve housing assembly through the suction packing seal assembly
Implementation Method 2
in the operation with high pressure and large displacement, due to long period of cyclic loading
Data Source
AI summary
A hydraulic end assembly structure of a plunger pump, comprising a valve housing assembly, a suction gland and a suction pressing cap. The suction gland is connected to the suction pressing cap, and the suction gland is connected to the valve housing assembly through the suction packing seal assembly.