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SPRAYING
It is a mechanical process of fragmenting liquids into droplets, but the key lies in how to evenly distribute them. Some techniques of spraying include:
Hydraulic spraying: Put the liquid under pressure, making it come out through a calibrated hole or nozzle
Pneumatic Spray: Place the liquid in a high speed air stream
Centrifugal spraying: Subjecting the liquid to the reaction forces generated by a rotating element
By combining the process of drop formation with the technique used to transport it to the target, it is also possible to classify the sprayers. In the hydraulic system (the most used) the formation of the drop is made by the pressure of the liquid and its transport by the kinetic energy that is produced.
WATER
The water to dilute the vaccine must be completely free of sanitizers with an added stabilizer and at a temperature between 18 – 25 ºC.
NOZZLE
The mouthpiece is one of the most important elements for carrying out spray vaccination. They are parts that have calibrated holes for vaccine release. By changing the nozzle and the working pressure, you can get drops of different sizes and flow rates.
Nozzle functions:
Volume: Determines the applied flow
Quality: Produce drops of a certain size
Uniformity: Proper distribution of the vaccine
Figure 1 . Modification of the drop diameter according to the pressure
The nozzles used for spray vaccination are adjustable. The most commonly used are variable cone nozzles, because when the body is rotated, the spray angle varies from a narrow jet with large drops to a wide cone with small drops.
The identification of the nozzles is carried out in accordance with the ISO standard, through a color code and / or through numbering. These specifications are defined for flat fan nozzles at a nominal pressure of 3 bars – Table 1-.
Higher pressure not only increases the flow rate of the nozzle, but also influences the size of the droplets and the wear rate of the holes.
Table 1 . The identification of the nozzles according to the ISO standard -through a color code and / or by means of a numbering-
OBJECTIVES TO BE FULFILLED BY A GOOD VACCINATION DEVICE
DROPLET FORMATION
A spectrum of drops between a maximum and a minimum defined as adequately as possible and according to the type of vaccination to be performed should be sought.
DROP TRANSPORT
It must emit a spray according to the type of vaccine to be used and it must also deliver the drops with...
