Hemispherical Piston Profile for Liquid Dispensing Syringe
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Solution Overview
Problem
Existing liquid dispensers face challenges in precise volume dispensing and minimizing air entrapment and residual material, particularly in industrial applications requiring controlled dispensing of liquids like adhesives and solder pastes.
Innovation Solution
A syringe design featuring a piston with a hemispherical surface profile and circumferentially-extending wiper seal, along with a radially inward ledge, to minimize air entrapment and residual liquid, combined with an adapter for pressurized air coupling and end caps for secure installation, facilitating precise and efficient liquid dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional piston with flat surface is used, then the structure is simple, but air entrapment occurs and residual material remains in the syringe
Solution Approach 1:
The piston surface is designed with a hemispherical shape instead of a flat surface. This curved geometry allows air bubbles to rise and escape along the spherical surface as the piston moves forward, preventing air entrapment. The hemispherical shape also enables complete evacuation of liquid material from the syringe barrel, minimizing residual material while maintaining manufacturing feasibility through standard molding processes.
2Productivity
If the piston moves quickly to increase productivity, then dispensing speed improves, but air entrapment increases
Solution Approach 1:
The hemispherical piston surface creates a self-cleaning effect during rapid movement. As the piston advances quickly, the curved surface guides air bubbles upward and outward, allowing them to escape before the piston completes its stroke. This geometric design maintains effective air evacuation even at high dispensing speeds, enabling increased productivity without compromising reliability.
3Loss of substance
If the syringe is designed to minimize residual material, then material utilization improves, but the piston structure becomes more complex
Solution Approach 1:
The hemispherical piston surface achieves minimal residual material through its geometric design alone, without requiring additional complex components. The curved surface allows liquid to be completely pushed forward and prevents material from adhering to the piston face, reducing waste to near-zero levels while maintaining a relatively simple single-piece piston structure that can be manufactured through standard injection molding.
4Reliability
If a wiper seal is added to the piston, then liquid retention improves, but gas passage becomes restricted
Solution Approach 1:
The wiper seal is positioned at the periphery of the piston where it contacts the barrel wall, creating a local sealing zone. This peripheral sealing arrangement allows the wiper to effectively retain liquid material while leaving the central hemispherical surface open for gas passage. The localized sealing function achieves liquid retention without compromising gas evacuation through the piston center.
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 syringe design reduces air entrapment, minimizes residual material, and ensures consistent dispensing volumes by effectively managing gas passage and liquid retention, enhancing the precision and efficiency of liquid dispensing processes.
Implementation Method 1
The piston has first and second ends, and the first end has a generally hemispherical shaped surface profile with an elongated apex extending along a central axis of the piston. The surface profile facilitates dispensing fluid from the first end of the barrel when the piston is moved in a direction toward the first end. The dispensing syringe reduces or eliminates air entrapment
Implementation Method 2
The syringe barrel includes a radially inwardly extending ledge within the interior reservoir. The ledge engages the wiper seal when the piston is moved toward the first end of the barrel to engage the piston with the first end. Engagement between the wiper seal and the ledge squeezes liquid material from beneath the wiper, thereby minimizing liquid material remaining in the reservoir
Implementation Method 3
The piston may be configured to permit gas to pass from the first volume, while retaining liquid within the first volume. In one embodiment, at least a portion of the piston is textured to facilitate passing gas from the first volume, while retaining the liquid.
Data Source
AI summary
A syringe for dispensing liquid materials to a substrate. In one embodiment, the syringe includes a barrel having a first end, a second end, and an interior reservoir. A piston is slidably disposed within the reservoir and is movable to increase or decrease a volume of the interior reservoir near the first end of the barrel. A first end of the piston has a hemispherically-shaped surface profile, with an elongated apex extending therefrom, to dispense liquid from the first end of the barrel when the piston is moved in a direction toward the first end.