Spray to protect your crops
spray 1
Compiled by J Fuls (Pr Eng)
The mechanics of a pump is very interesting and consists of the basics on which most spraying mechanisms function. It is therefore beneficial for a farmer to know how it works. This month we look closely at nozzles and pumps.
We thank the ARC Institute for Agricultural Engineering in South Africa, who made this article available to the readers of ProAgri Zambia.
Nozzle markings
The markings on the nozzles are very small and one has to have strong eyes to be able to read it. One can however do the following to make the markings more readable:
1. Make your finger a little dirty on muddy soil
2. Wipe your dirty finger over the markings, but be careful not to wipe dirt into the nozzle hole.
3. Carefully wipe
the excess dirt off on your hand palm.
This is the result on a nozzle with a light colour, like yellow.
Nozzle types and their application
One can do much the same with school board chalk if one can get hold of some, especially on a dark nozzle like red.
1. Wipe the chalk over the markings in all directions.
2. Carefully wipe
the excess chalk
off on your hand
palm.
This is the result on a nozzle with a dark colour, like red.
Pumps
To get the spraying chemicals out of the tank and to the spraying nozzle, one needs a pump. This pump must be able to put pressure on the muti, so that the nozzle can spray as it is supposed to do. (Remember how the bicycle pump made a spray when pumping hard)
How do pumps work?
A sprayer pump can be compared to a bicycle pump.
When we put the pump together again, it looks like this inside:
The bicycle pump pumps air, but if the whole pump is held under water, it will pump water instead of air.
Other pumps work much the same as the bicycle pump. Compare the pump below with the bicycle pump which is connected to the bicycle wheel. Note that it has the same components:
The main differences are that this piston pump has a separate handle to push the push rod, just like the pump of a knapsack sprayer, the wheel valve of the bicycle serves as the outlet valve for the bicycle pump.
On a tractor sprayer, the pump is outside the tank:
This is how the pump works:
As the piston is moved out by means of the handle, the inlet valve will open to let liquid flow from the tank into the pump. The outlet valve remains closed to stop liquid from returning once it was pushed out.
The reverse happens when the handle is moved in for pumping:
Next month we shall look at the different kinds of sprayers.
Published with the acknowledgement to the ARC Institute for Agricultural Engineering for the use of their manuals. Visit www.arc.agric.za for more information.
Related Posts
