Thermal Micro-Fluidic Dispensing for Prolonged Airborne Fragrance
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Solution Overview
Problem
Existing material dispensing systems, such as thermal ink-jet systems, fail to effectively disperse materials in an environment for an extended period, as the volatile oil droplets quickly settle, reducing the concentration of fragrances and materials in the atmosphere.
Innovation Solution
A thermal micro-fluidic system with a substrate-based heating element, dielectric shielding, and a controlled dispensing mechanism that uses a reservoir connected to a print head with optimized chamber and nozzle ratios, enabling efficient ejection of superheated liquid droplets into the environment at high frequencies, allowing for prolonged airborne dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal ink-jet systems are used to disperse volatile oils, then the material can be dispersed in the environment, but the oil droplets quickly settle out resulting in reduced concentration in the atmosphere
Solution Approach 1:
The patent changes the physical parameters of droplet generation by using a highly segmented flow approach with multiple small orifices instead of traditional single large droplets. This creates numerous tiny droplets with different settling characteristics that remain airborne longer, directly addressing the contradiction between maintaining concentration and extending airborne duration
Solution Approach 2:
The system segments the volatile oil into many small droplets through a multi-orifice dispensing head where each orifice produces individual droplets. This segmentation increases the total surface area and creates a distribution of droplet sizes that resist settling better than single large droplets, thereby extending airborne time while maintaining fragrance concentration
2Productivity
If traditional thermal jetting systems are used, then material dispersion is achieved, but the droplet size is too large causing rapid settling
Solution Approach 1:
The patent transitions from single-droplet dispensing to a multi-dimensional array of droplets by using multiple orifices arranged in a grid pattern. This dimensional approach allows simultaneous ejection of many small droplets, achieving high productivity while each individual droplet remains small enough to resist settling
Solution Approach 2:
The system changes the droplet size parameter by using orifices with diameters significantly smaller than traditional jetting systems (on the order of micrometers). This parameter change creates droplets that are small enough to remain airborne while the high number of orifices compensates for individual droplet size, maintaining overall dispersion efficiency
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 system achieves prolonged airborne dispersion of materials by producing smaller droplets than the nozzle diameter, maintaining a higher concentration of fragrances and materials in the environment, overcoming the settling issue of traditional systems.
Implementation Method 1
Selective manipulation of the ratio of the length L2 to the chamber height H, and/or the ratio of the diameter D to the chamber height H in the design and fabrication of the chamber, die and nozzle elements may advantageously enable operating conditions for the system. Such conditions include the ability to discharge fluid from the nozzles at rates in excess of the ability of the fluid to completely refill the chambers. A consequence of this mode of operation is that the droplets of fluid discharged from the nozzles may be smaller than the nozzle diameter D
Implementation Method 2
Liquid disposed within the chamber may be selectively volatilized by the transfer of energy from the activation element to the liquid. The activation element may comprise a resistive heating element or a piezoelectric element. Upon the transfer of sufficient energy to the liquid, (for example in the case of thermal activation) at least a portion of the liquid will become superheated and will vaporize.
Data Source
Figure 1
Figure 2
AI summary
A liquid dispensing method including steps of: providing a dispensing device having a refill time (RT) and repeatedly energizing the activation elements at a frequency greater than about 1/(RT). The device includes: a plurality of liquid dispensing elements, each element including: a chamber having a height (H), a nozzle having a diameter (D), an activation element having a length (L), and the refill time (RT); a liquid containing reservoir in fluid communication with the liquid dispensing elements; and a control element in electrical communication with the liquid dispensing elements. The ratio of the nozzle diameter (D) to chamber height (H) is between about 3 and about 10.