A Pollution Free Aerosol Dispenser 

This Small Business Innovation Research project involved the development of a consumer aerosol dispenser that seeks to eliminate the volatile organic compound (VOC) solvents and hydrocarbon (HC) propellants used in many commercial sprays.  For 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 Phase I project 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.  The SETScan^® 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.  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 was also found to be very uniform. 

Phase I feasibility of obtaining a narrow drop size distribution using effervescent atomization in conjunction with the micro-machined nozzles was conclusively demonstrated.  Effervescent atomization is insensitive to the viscosity of the fluid.  Therefore, the technique can be directly incorporated for a wide range of consumer products.  The commercial application is therefore, as a general purpose, pollution free aerosol dispenser.