TECHNICAL STUDY OF SOME MAJOR PARAMETERS INFLUENCING THE PERFORMANCESOF AN AEROSOL DELIVERY EQUIPMENT SUITABLE FOR CALVES

Aerosol delivery equipment, suitable for the treatment of bovine respi ratory dysfunctions and including 2 parallely positioned jet nebulizer s, was studied in depth in order to determine the optimal working cond itions in the field. Indeed, some factors might reasonably alter the p erformance of this equipment. Among these factors, the influences of t he parallel position of jet nebulizers (in order to accomodate the bre athing requirements of the cattle and achieve a rapid treatment), of t he long feed pipe delivering compressed air (in order to keep the anim al away from the compressor unit), and finally of the ambient temperat ure were studied, this equipment being essentially used during the win ter season. This equipment could accomodate the breathing needs of cat tle weighing up to 225 kg if a pressure of 600 kPa was developed upstr eam to the nebulizers. The rate of atomization was significantly reduc ed when working at ambient air temperatures (272.25 K < T < 274.65 K) close to those encountered in winter. This was especially true when pr essure upstream to the nebulizers did not exceed 500 kPa. The immersio n of the feed pipe for compressed air in hot water led to an increase in the rate of atomization without raising evaporative water losses, a nd reduced the drop in temperature in the nebulizer solution. Finally, the rate of atomization significantly increased when the face mask in cluding the nebulizers was maintained so that the nebulizers were in a vertical position or at an angle not less than 60 degrees with respec t to the ground.