Liquid Ejection Device Pulsation Control for Droplet Formation
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Solution Overview
Problem
Existing liquid ejection devices face challenges in workability due to long standoff distances and increased equipment size, particularly when ejecting liquids with high energy, and continuous liquid ejection configurations require extensive workspace and complex temperature control.
Innovation Solution
A liquid ejection device incorporating a nozzle, liquid transporting pipe, pulsation generator, pump, and control unit that sets the Vf/Q ratio to 0.3 or more, allowing for efficient dropletization and reducing the droplet formation distance to 20 mm or less, while the pulsation generator operates at frequencies between 5 kHz and 15 kHz to maintain stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a liquid is continuously ejected and dropletized, then material management is simple and device size is reduced, but the interval from the ejecting unit to the object becomes long
Solution Approach 1:
The patent applies periodic pulsation to the liquid chamber to generate droplets at regular intervals. The pulsation generator creates periodic volume changes in the liquid chamber, causing the liquid to be ejected as discrete droplets rather than continuous flow, thereby reducing the standoff distance while maintaining simple material management
Solution Approach 2:
The patent changes the volume parameter of the liquid chamber through pulsation to control droplet formation. By varying the chamber volume periodically, the system achieves droplet ejection at a shorter distance from the nozzle, resolving the contradiction between device size and ejection distance
2Power
If a liquefied gas is mixed and ejected with high-pressure liquid, then the liquid has large energy, but temperature control and equipment size increase
Solution Approach 1:
The patent introduces a pulsation generator as an intermediary device to transfer energy to the liquid. Instead of using complex liquefied gas systems, the pulsation generator acts as a mediator that creates high-energy droplet ejection through mechanical pulsation, simplifying the overall equipment while maintaining high liquid energy
Solution Approach 2:
Periodic pulsation is applied to the liquid chamber to generate high-energy droplets. This periodic action concentrates energy delivery into discrete pulses, achieving high liquid energy without requiring continuous high-pressure systems or temperature-controlled liquefied gas storage
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 improves workability by achieving efficient droplet formation and reducing the droplet formation distance, enhancing the reliability and efficiency of liquid ejection processes, such as cleaning and surface processing, while minimizing equipment size and complexity.
Implementation Method 1
a pulsation generator configured to change a volume of a liquid chamber coupling to the liquid transporting pipe
Data Source
AI summary
A liquid ejection device includes: a nozzle through which a liquid is ejected; a liquid transporting pipe coupling to the nozzle; a pulsation generator configured to change a volume of a liquid chamber coupling to the liquid transporting pipe; a pump configured to send a liquid to the liquid transporting pipe; and a control unit configured to control driving of the pulsation generator and the pump. The control unit drives the pulsation generator and the pump such that Vf/Q is 0.3 or more, in which V [mm3] is a volume change amount of the liquid chamber, Q [mL/min] is a flow rate of a liquid to the liquid transporting pipe by the pump, and f [kHz] is a frequency at which the pulsation generator applies a pulsation to a liquid.