Diesel Pump Plunger Sealing Ring for Leakage Control
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Solution Overview
Problem
High-pressure fluid pumping applications face significant leakage issues due to bore dilation, which increases fluid leakage and is costly to control, and existing sealing solutions are complex, costly, and prone to wear.
Innovation Solution
A diesel fuel pump with a pumping plunger featuring a recessed end region and a sealing ring with a radial orifice and longitudinally tapered region, allowing for controlled leakage and expansion to maintain a tight seal, and a retaining member with a graduated diameter to secure the sealing ring, which is dimensioned to provide a predetermined leakage rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If accurate sizing of plunger and bore is used to control leakage, then leakage is limited to acceptable levels, but processing cost increases due to fine surface finish and precision geometry requirements
Solution Approach 1:
The invention applies a sealing ring only at the specific location where leakage occurs (at the plunger end within the bore), rather than requiring precision throughout the entire plunger and bore surfaces. This localized sealing approach maintains effective leakage control while significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The sealing ring acts as an intermediary element between the plunger and bore, providing the sealing function without requiring direct precision contact between the plunger surface and bore surface. This mediator component handles the sealing task, allowing the main components to be manufactured with standard tolerances.
2Loss of substance
If a packing or stuffing box sealing arrangement is incorporated, then leakage is controlled in noxious fluid applications, but device complexity and cost increase
Solution Approach 1:
The invention extracts only the essential sealing function from complex packing or stuffing box arrangements. By using a simple annular sealing ring with a radial gap, it achieves the necessary leakage control without the excessive complexity of traditional packing mechanisms.
Solution Approach 2:
The sealing ring incorporates a radial gap that allows it to expand and contract in response to pressure changes. This parameter change enables the sealing ring to adapt to bore dilation under pressure while maintaining effective sealing, providing a simple yet effective solution to the leakage problem.
3Loss of substance
If a sealing ring with radial gap is used, then leakage is controlled across wide pressure ranges, but manufacturing precision requirements increase
Solution Approach 1:
The sealing ring is designed with a radial gap that allows it to dynamically adjust its dimensions in response to pressure changes. Under high pressure, the ring expands to maintain sealing contact with the bore, while the radial gap prevents excessive force buildup. This dynamic adaptation simplifies manufacturing requirements compared to a completely rigid precision seal.
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 solution effectively controls leakage across a wide range of pressures, preventing excessive pressure drop and wear, while maintaining a tight seal and reducing the need for complex sealing arrangements, thus addressing the leakage and cost issues in high-pressure pumping.
Implementation Method 1
the orifice is a radial gap in the sealing ring
Implementation Method 2
the sealing ring includes a longitudinally tapered region
Implementation Method 3
a spring is disposed between the first and second semi-circular ring portions
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A pumping plunger (14) for a fluid pump (2), wherein the plunger (14) carries sealing means (60, 64, 70). In a particular embodiment, the sealing means takes the form of a discontinuous annular member received over a relatively narrow end portion of the plunger, the annular member serving to maintain an effective high pressure seal against a suitable bore within which it is slidable, in use. Accordingly, the invention extends to a pump incorporating such a plunger.