Grantee Research Project Results
Final Report: A Pollution-Free Aerosol Dispenser
EPA Contract Number: 68D01020Title: A Pollution-Free Aerosol Dispenser
Investigators: Sivathanu, Yudava
Small Business: EnUrga Inc.
EPA Contact:
Phase: I
Project Period: April 1, 2001 through September 1, 2001
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2001) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , SBIR - Air Pollution , Small Business Innovation Research (SBIR)
Description:
This Phase I project involved the development of a consumer aerosol dispenser that eliminates the volatile organic compound (VOC) solvents and hydrocarbon (HC) propellants used in many commercial sprays. The two distinguishing features of the dispenser are: (1) application of ligament-controlled effervescent atomization for producing very small droplets independent of the fluid viscosity, and (2) a microlaminated nozzle to control both the Sauter mean diameter (SMD) and the distribution of drop sizes. These two features allow for the elimination (reduction in certain applications) of VOC carrier liquids and HC propellants in conventional aerosol dispensers.In consumer products, large droplets in the spray can cause excessive wetting, while small droplets are easily inhalable. Therefore, it is crucial to achieve a narrow drop size distribution, particularly under transient injection. The targeted drop size by the consumer spray industry is approximately 50 microns. The advantage of using effervescent atomization is that the injectors are expected to be insensitive to fluid properties. The major task for the Phase I work was to design and fabricate a prototype aerosol container. During the Phase II work, commercially available products that have VOCs will be sprayed using nitrogen instead of HC propellants, and reformulated products (which are dissolved in nonpolluting carriers) will be sprayed using nitrogen. The major tasks for the Phase I work were to design, fabricate, and evaluate a prototype aerosol container.
Summary/Accomplishments (Outputs/Outcomes):
En'Urga, Inc., was successful in designing and fabricating a prototype dispenser. Evaluation of the dispenser using two different nozzle tips was completed. Two separate instruments were used to evaluate the prototype dispenser. A Malvern Particle Analyzer was used to obtain the drop size distribution of the sprays at different operating pressures. An optical patternator was used to obtain the uniformity of the spray and detect the presence of any streaks or voids.The nozzle was tested at pressures ranging from 20 to 100 psi. An extensive coupling between the pressure and the air-to-liquid ratio was observed. This coupling prevented independent setting of the pressure and the air-to-liquid ratios. Therefore, an additional external valve was introduced into the line to obtain acceptable air-to-liquid ratios at 100 psi. The prototype dispenser provided drop sizes in the 40 to 60 micron range for pressures ranging from 20 to 100 psi. The drop sizes are ideal for consumer spray applications, and the pressure ranges tested imply that the technology is feasible for consumer products. The quality of the spray obtained also was found to be very uniform.
Conclusions:
The following conclusions were made during the Phase I project:? The pollution-free aerosol dispenser provided drop sizes with an SMD of 40 to 60 microns for pressures ranging from 20 to 100 psi.
? Some design changes in the pressurizing mechanism and/or valves are required to maintain the air-to-liquid ratios at lower levels at high pressures.
? The aerosol dispenser provided very uniform spray patterns, even at very low pressures.
Based on the above conclusions, the Phase I feasibility of obtaining a narrow drop size distribution using effervescent atomization in conjunction with the micromachined nozzles is conclusively demonstrated. Effervescent atomization is insensitive to the viscosity of the fluid; therefore, the technique can be directly incorporated into a wide range of consumer products. The commercial application is, therefore, as a general purpose, pollution-free aerosol dispenser.
Supplemental Keywords:
pollution-free aerosol dispenser, paint spray dispenser, VOC-free dispenser, air-propelled dispenser., RFA, Scientific Discipline, Air, Toxics, Chemical Engineering, particulate matter, exploratory air engineering, air toxics, Environmental Chemistry, VOCs, Analytical Chemistry, exploratory air chemistry and physics, Environmental Engineering, Engineering, Chemistry, & Physics, 33/50, emission control strategies, air pollutants, Propellants, hydrocarbon, ambient air, consumer aerosol dispenser, atmospheric aerosols, aerosol dispenser, efferescent atomization, hydrocarbons, aerosol, Volatile Organic Compounds (VOCs)The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.