Adaptive Piston Pump Preload Seal for Leakage and Wear
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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 seal's effectiveness over time.
Innovation Solution
A piston pump design featuring a piston sleeve member with a sliding mechanism that includes an outer disc and a spreader disc, where the spreader disc engages the outer disc to enhance the seal with the chamber wall, reducing leakage by adjusting the camming surfaces to control fluid flow directionally.
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 invention introduces a dynamic adjustment mechanism where the disc's engagement with the chamber wall can be varied during operation. The disc is biased outwardly by a spring to engage the chamber wall for sealing, but this engagement can be dynamically adjusted during piston movement to maintain sealing while reducing movement resistance
Solution Approach 2:
The invention changes the parameter of disc engagement force from a fixed strong bias to a variable bias that can be adjusted during operation. The spring provides a baseline outward bias for sealing, while allowing the engagement force to be modulated during piston movement to balance sealing effectiveness with movement ease
2Duration of action of stationary object
If a disc is compressed in the chamber over time, then the material develops set which reduces inherent bias, but this increases the risk of leakage past the seal
Solution Approach 1:
The invention applies preliminary action by providing a spring that continuously biases the disc outwardly toward the chamber wall. This pre-applied force compensates for the material set that develops during compression over time, maintaining adequate sealing pressure throughout the service life of the seal
Solution Approach 2:
The spring mechanism provides continuous feedback compensation for disc compression. As the disc material sets and loses inherent bias during operation, the spring maintains the necessary outward force to keep the disc engaged with the chamber wall, automatically compensating for degradation without requiring adjustment
3Reliability
If the inherent resiliency of the disc is increased to improve sealing, then sealing effectiveness is improved, but wear of sealing surfaces affects the extent to which seal is adequately provided
Solution Approach 1:
The invention changes the parameter of sealing force from relying on the disc's inherent material resiliency to using an externally applied spring force. This allows the use of less resilient (and thus more wear-resistant) disc materials while maintaining adequate sealing pressure through the spring bias
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 enhancing the seal engagement with the chamber wall, maintaining pressure and preventing fluid leakage, while minimizing the forces required for piston movement.
Implementation Method 1
the outer disc having a cam surface annularly thereabout outwardly of the sleeve stem
Implementation Method 2
the spreader disc having a camming surface in opposition to 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
Data Source
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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 (18) to dispense fluid, a piston slide member (120) is urged into a sealing disc of a piston sleeve member (100) 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.