Pressure-Responsive Valve for Leak Prevention in Liquid Writing Implements
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Solution Overview
Problem
Free-ink-type writing implements are prone to leaks due to elevated internal pressure relative to ambient pressure, and existing solutions either interfere with consistent ink dispensing or risk clogging when attempting to prevent leaks.
Innovation Solution
A writing implement with a normally-open valve connected to a baffle or buffer system that regulates liquid flow from the reservoir to the applicator tip, closing when internal pressure exceeds a predetermined amount, and includes a gas passage to maintain ambient pressure and prevent leaks, using a deformable flow control portion and umbrella valve design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional baffle system with lamella is used to limit ink flow speed, then the complexity and cost of the system increase, but the system is unable to prevent leaks when internal pressure remains elevated
Solution Approach 1:
The patent changes the operational parameter of the valve from a fixed state to a pressure-responsive state. The valve transitions between open and closed positions based on the pressure differential across the reservoir, automatically preventing leaks when internal pressure exceeds a predetermined threshold while maintaining simple system architecture
Solution Approach 2:
The valve system operates autonomously by sensing the pressure differential across the reservoir and automatically adjusting its state to prevent leaks. The elastic member deforms in response to pressure changes, closing the valve when needed without requiring external control mechanisms, thereby maintaining reliability while minimizing complexity
2Reliability
If a valve or seal is attached to the nib and actuatable by depression to open, then the system can control ink flow, but it interferes with consistent dispensing when contact pressures are not sufficient to open the valve
Solution Approach 1:
Instead of requiring user action to open the valve during normal operation, the system inverts the logic by keeping the valve open during use and requiring pressure buildup to close it. This inversion ensures consistent ink dispensing during normal operation while providing leak prevention when the writing implement is not in use or when excessive pressure occurs
3Productivity
If a pen vent is exposed to the atmosphere to allow ink deposition, then ink can be deposited consistently, but the pen vent is at risk of clogging
Solution Approach 1:
The valve acts as an intermediary between the internal reservoir pressure and the external atmosphere. It allows pressure equalization through controlled openings while preventing direct exposure of the vent to atmospheric contaminants that could cause clogging, thus maintaining both ink deposition capability and vent reliability
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 prevents leaks while allowing consistent ink deposition at low contact pressures, maintaining a steady flow and preventing clogging, ensuring reliable operation and consistent performance.
Implementation Method 1
The valve includes an elastic member deformable in response to a pressure differential across the reservoir so as to close the valve when the internal pressure within the reservoir exceeds a reference pressure by more than a predetermined amount
Data Source
Figure 1A~1B
Figure 2~4
Figure 5~6
AI summary
A writing implement including a reservoir for storing a liquid, an applicator tip (3) for depositing the liquid on a surface, a buffer (2) connected to the reservoir and connected to the applicator tip (3) so as to transport the liquid from the reservoir to the applicator tip (3), and a normally-open valve separating the buffer (2) from the reservoir, the valve being configured to close, to prevent flow of the liquid from the reservoir to the buffer (2), in response to internal pressure within the reservoir exceeding a reference pressure outside of the reservoir by more than a predetermined amount.