DUST SUPPRESSION SYSTEM

 The result is that the probability of collision between a droplet and particle is greatly increased from the spatial probability, implying the need for  water droplets to ensure the desired efficiency. if the diameter of the droplet is much greater than the dust particle then the dust particle simply follows the air streamlines around the droplet and little or no contact occurs. on the other hand, the water droplet is of a comparable size to the dust particle then contact occurs as the dust particle tries to follow the air streamline. Thus, a nozzle generating a dense fog of 1-10 micron size droplets can be used to envelop and some other dust particles at their source and prevent them from becoming airborne.

 The ultrasonic atomizing system generates droplets averaging 10 micron in size and is capable of suppressing sub-micron dust particles. In addition to this particle size theory, the results of additional research indicate there is another significant phenomenon that occurs when ultrasonic atomizing systems are applied to dust suppression. The effect can be compared to an electrostatic precipitator in which dust particles are charged and then collected on plates of opposite charge. It was found that dust particles generally carry certain negative potential depending on the nature of the dust and the ambient conditions. Water droplets produced by the nozzles carry a charge that is strongly positive in relation to the dust particles.

 The theory behind the ultrasonic atomizing system is based on research considering a water droplet from a spray that is about to impinge on a dust particle. The probability of impaction increases as the size of the water spray droplet decreases. This explains why conventional hydraulic water sprays are not effective on respirable dust. With typical diameters of 200-600 microns the droplets are much larger than the dusts they are attempting to suppress.

 Factors affecting the efficiency of water-droplet formation are particle size, particle solubility, particle (hydrophobic or hydrophilic), presence of hygroscopic salts, charge, temperature, relative humidity, pressure, electric fields, wettability.  The efficiency of spray dust capture will increase  by increasing the probability of water droplet and respirable dust particle contact. It is increased by increasing the number of smaller sized spray droplets per unit volume of water utilized  optimizing the energy transfer of spray droplets with the dust-laden air. Improving water droplet and dust particle interaction depends upon spray nozzle technologies.

The dust suppression system is meant to suppress the dust generated during transfer of material at feed/discharge points of con