During my travels, at the end of the field demonstrations with the mist sprayer, one of the most common questions that people ask (except for how much is the machine) is the following:
What is the difference between the mist sprayer and the knapsack pump?
Although the purpose of both machines is the treatment with phytosanitary products, their functioning is very different.
The knapsack pump (both manual and engine version) generates a pressure inside the tank which pushes the product, through an exit pipe, towards the nozzle that sprays on the crops to be treated. The treatment called high volume occurs with drops not uniform and with big dimensions 200-400 microns; they covers only a part of the leaves because the drops too heavy fall to the ground.
The mist sprayer is equipped with a fan that generates a great volume of air that is conveyed, through a pipe, to the exit nozzle at the bottom of the throwing pipe; thanks to its high speed (125 meters/sec, about 450 km/h), the product is nebulized in drops of an average size of 90 100 microns (one micron = 0,001 millimeters) and carried towards the crops. This system called low volume allows to obtain a treatment with greater protection, because the uniform micronization of the drops, combined with the action of the air that moves the leaves, creates a patina of product in the upper and lower part of them.
During the demonstrations in the field, to verify the distribution, some hydro-sensitive paper is placed between the leaves: this paper has the property of changing color with the contact of water, showing the distribution obtained.
The mist sprayer also allows to work with a more concentrated product (therefore using a fewer quantity of water).
For example, treating one hectare of cultivation with the knapsack pump need approximately 400 liters of water, with the mist sprayer is possible to perform the same work with a quantity which can vary from 100 to 150 liters; of course these values are purely indicative because they may change depending on the type of crop, its inflorescence, type of the ground, etc..
Furthermore the Cifarelli mist sprayer, using the great speed of the air flow, obtains a valid covering (98%) of the leaves up to a distance of 10/11 meters, horizontally and / or vertically.
The mist sprayer is more effective in applications of phytosanitary products in agriculture and insecticides treatments in public hygiene.
The knapsack pump is suitable in the herbicide treatment, because the size of the drop is appropriate to penetrate the ground and to attack the roots of infesting grasses.
How to use the mist sprayer?
The mist sprayer is placed on shoulders, adjusting the length of the shoulder straps, so that the machine is well adherent to the back and shoulders.
The throwing tube has to be addressed towards the parts to be treated, regulating the liquid cock and the revolutions of the engine (rpm) to obtain the dimension of the drops you need:
- use the wide spray jet to obtain a large range;
- use the spray jet (without wide spray jet) to obtain a long range.
How to address the product flow?
- By executing an elliptical rotation from right to left side while treating in open field (vegetables, potatoes, salad, etc.).
- By executing an “U” while treating plants, espalier cultivations and walls for disinfestations.
How to adjust the product flow?
- The quantity of product distributed is adjustable by regulating the 5 positions of the cock presents on the throwing tube (position 1 of the cock delivers 0.14 L / min while in position 5 are 3.60 L / min, speaking of a mist sprayer without booster pump ). Greater is the amount of product, bigger will result the drops:
- position 1 – maximum acceleration: smaller drops;
- position 2,5 – ¾ of acceleration: medium drops (100-120 microns).
Before leaving, I remind that there are some recommendations to follow while working with a mist sprayer (and knap sack pump):
- safeguard your person by wearing a breathing protection mask, safety glasses, hearing protection systems, gloves and protection boots;
- avoid treatments in presence of strong wind;
- it’s not recommended the treatment in the warmer hours of the day, to avoid the rapid evaporation of the drops;
- never point the throwing tube toward people, animals or inhabited places;
- at the end of the treatment wash yourselves and the clothes worn.
For the mist sprayer exist accessories for adjusting the amount of product dispensed, inclined grids, double output and other devices that will be described soon.
