Adaptive Piston Pump Seal With Camming-Enhanced Leak Control
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Solution Overview
Problem
Piston pumps face issues with seal leakage due to material set and increased forces required for piston movement, as well as wear on sealing surfaces, which affect the effectiveness of fluid containment.
Innovation Solution
A piston pump design featuring a piston sleeve member with a radially extending outer disc and a piston slide member having an inner disc and spreader disc, where the slide member moves to enhance the seal engagement with the chamber wall, reducing leakage by utilizing a camming surface to urge the outer disc into the chamber wall during the retraction stroke and allowing fluid flow during extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a disc is designed with strong inherent bias to engage the chamber wall to prevent leakage, then sealing effectiveness is improved, but the forces required to move the piston increase
Solution Approach 1:
The patent applies dynamics by making the seal engagement force variable rather than constant. The bellows-shaped seal provides dynamic engagement where the sealing force increases with chamber pressure, allowing strong sealing when needed while reducing movement resistance during piston travel.
Solution Approach 2:
The bellows configuration changes the physical parameters of the seal, transforming it from a rigid disc to a flexible element that can change its engagement characteristics. This allows the seal to adapt its radial outward force based on operating conditions, optimizing both sealing and mobility.
2Reliability
If a disc seal is used with inherent resiliency to maintain engagement with the chamber wall, then sealing is improved initially, but material set over time reduces the bias and increases leakage risk
Solution Approach 1:
The patent uses a bellows-shaped flexible seal that maintains its sealing capability through repeated compression cycles. The flexible construction allows the seal to recover its shape after compression, preventing permanent set and maintaining sealing effectiveness throughout the service life of the pump.
Solution Approach 2:
The bellows configuration provides built-in compliance that cushions the seal against excessive compression forces. This prevents the material from reaching its elastic limit and undergoing permanent deformation, thereby extending the service life of the sealing element.
3Reliability
If a disc seal is used in the piston, then fluid containment is achieved, but wear of the sealing surfaces affects the extent to which seal is adequately provided
Solution Approach 1:
The flexible bellows seal conforms to the chamber wall surface, distributing wear across a larger area and accommodating surface irregularities. This flexibility allows the seal to maintain effective contact despite wear, extending the durability of the sealing arrangement.
Solution Approach 2:
The dynamic nature of the bellows seal allows it to adapt to wear by changing its engagement characteristics over time, maintaining adequate sealing pressure even as the sealing surfaces wear. This self-adjusting property prolongs the functional life of the sealing system.
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 design effectively reduces the tendency of seals to leak by maintaining a strong seal engagement with the chamber wall, minimizing fluid leakage while reducing the forces needed for piston movement and mitigating wear-related issues.
Implementation Method 1
an outer disc on the sleeve stem and extending radially outwardly from the sleeve stem circumferentially thereabout to engage the chamber wall to form a seal therewith against fluid flow therepast
Implementation Method 2
the spreader disc having a camming surface in opposition to the cam surface of the outer disc, in the extension condition the camming surface of the spreader disc is axially spaced from the cam surface of the outer disc, in the retraction condition the camming surface of the spreader disc engaging the cam surface of the outer disc to urge the edge portion of the outer disc radially outwardly into the chamber wall
Implementation Method 3
the inner disc engaging the chamber wall axially inwardly of the spreader disc to substantially prevent fluid flow in the chamber past the inner disc in an inward direction
Implementation Method 4
a one-way valve between the reservoir and the chamber permitting fluid flow through the inner end of said chamber, only from the reservoir to the chamber
Data Source
AI summary
A piston pump dispenser having a reciprocating piston pump arrangement in which in a dispensing stroke in which fluid is pressurized in a chamber to dispense fluid, a piston slide member is urged into a sealing disc of a piston sleeve member to increase the extent to which the sealing disc provides a seal with a wall of the chamber against fluid leaking out past the seal disc.