Introduction

In the first and notebooks of this series, I’ve started to calculate what is the correct spray volume for an orchard and a vineyard. The answer was one nozzle using one pressure.

If I make some small changes on flow rate using pressure variation, I will get a non-linear variation.

But the question is: should I spray a tree the same way all way to the top? I’ve addressed that question on this infografhic. Well, don’t forget that I have to use the same pressure, although there could be some small variations along the hose. So, the total amount of flow rate will depend on the same pressure value.

Let’s make some tests in order to choose, not only one nozzle, but a set of proper nozzles.

Albuz ATR 80 hollow cone nozzles.

Let’s reuse some classes that I’ve created on the first notebook:

But with some changes:

Let’s spray

The same places in the same old way.

Let´s get the flow rate for this application, and the right nozzle

ORANGE

15.0

17.0

Now I know that I have to use 10 Orange nozzles at 15 bar to get a sum of 17 L/min in the sprayer.

What if I want to use more than one nozzle color?

I will use a quite simple way. A lower flow rate nozzle to the bottom of the tree and higher flow rate nozzle to the top. The Class Nozzle now have two useful attributes that help me to find out which ones.

the_right_nozzle.upper_color_code 'RED' the_right_nozzle.lower_color_code 'YELLOW'

So, 5 nozzles each side of the sprayer, according to the following sequence:

1 YELLOW (bottom)

3 ORANGE (medium)

1 RED (top)

Finally, I will just check if the sum of the different flow rates is close to the calculated previously:

COLOR_CODES[3], PRESSURES[10], FLOW_RATES[10,3] ('YELLOW', 15.0, 1.25) COLOR_CODES[4], PRESSURES[10], FLOW_RATES[10,4] ('ORANGE', 15.0, 1.69) COLOR_CODES[5], PRESSURES[10], FLOW_RATES[10,5] ('RED', 15.0, 2.33) (FLOW_RATES[10,3] + 3 * FLOW_RATES[10,4] + FLOW_RATES[10,5]) * 2 17.3

Quite good. I’ve changed the vertical distribution but I’ve kept (almost) the total sprayer flow rate.

Resources

This work is made of four ingredients: some ideas, lots of discussion with colleagues and farmers, support from Impactwave team (specially Gonçalo Martins) and all the effort of the Python community: