Continuous Rinsing – the new big thing in spraying?

1. Continuous Rinsing
Dr. Jason Deveau ● OMAFRA Application Technology Specialist ● 2017

2. • An “empty” sprayer can still
retain a lot of standing volume.
• In some large sprayers, the lines,
sump and pump can easily retain
20 gal.
• Repeated rinses (or tank dumps
due to bad math) in the same
location are a significant source
of surface water contamination.

3. France (2006) and Denmark (2009)
legislated that a sprayer cannot leave
the field with >1% or 2% (resp.) of
the original tank mix concentration...
…as sampled
at the nozzle.

4. This is significant because research
showed that sprayers can retain 10-15%
of the original concentration in
empty/fill valves, boom ends & filters...
P.G. Anderson et al. 2010
…while rinsate still measured
only 1-2% at the nozzle.

5. So let’s define some terms:
Cleaning: Total decontamination
performed when changing chemicals,
moving into sensitive crops, and at
the end of every spray day.
Requires the use of a detergent and
any label-required additive.
Requires the operator to address
filters and dead-end plumbing areas.

6. You’d be amazed at
what accumulates in
sagging lines and
boom ends…
Photo:HJVEquipment.

7. Helmut and I delivered this demo at
the Outdoor Farm Show in 2015.

8. And yet, boom ends are STILL a big
deal. As of Feb. 9 2017, ~25% still
have dead-ends with caps.
Feb 8, 2017

9. Each section end can bleed residue
into the spray as the boom charges.
And, if using new dicamba products,
cleaning cannot be ignored.
Photo: Paul Van Den Borre… but he didn’t do this.

10. Rinsing: Dilutes residual spray mix,
but does not address dead-end
plumbing.
Should be performed every few loads,
when moving empty sprayer between
fields, and at minimum if the
operator has (unwisely) decided not
to fully clean the sprayer at the end
of the day.

11. The power of dilution
Dilution Factor = Rinse volume + Remaining spray mix
Remaining spray mix
• A single rinse of 150 gal. to 20 gal.
leftover mix: Dilution factor of 8.5.
• But, serial dilution means 50 gal. to
20 gal. leftover, three times: Dilution
factor of 3.5 x 3.5 x 3.5 = 43!

12. Triple Rinse
Clean water mixed with spray mix, then
sprayed out. Three serial dilutions.

13. • If I can’t convince you to clean
daily, perhaps I can convince you
to rinse more regularly…
• Who wants to do a 30-40 minute
triple rinse multiple times a day?
• No one. But
what if there
was a faster
and easier
way?
Rinse more
often!

14. • Europe has adopted a different way
to rinse.
• By adding a small dedicated pump,
clean water moves directly to the
rinse nozzles while the main pump
sprays the rinsate.
Continuous Rinsing

15. 1. Minimize remainder (accurate
mixing).
2. Engage rinse pump as pressure
drops (in field).
3. Let it build up a bit, then drive and
spray.
4. Ensure pump capacity slightly less
than boom rate (air bubbles help).
5. Spray until empty.
Method

16. Continuous Rinse
Clean water pushes out spray mix
from behind.

17. Research in Europe showed
continuous rinsing reduced residue at
the nozzle to 2% in far less time,
without the operator leaving the cab.

18. Working with HJV, we modified a
RoGator 700 for Canada’s Outdoor
Farm Show in 2016.

19. 1 - From fresh water tank via
existing lines to a manifold…
2 – …into two, 7.5 gpm (@50 psi)
electrical roller pumps…
3 - …through backflow prevention valves… 4 - …teed into the existing rinse system.

20. • Electrical pumps were cheaper,
but if there’s capacity, hydraulic
pumps may have better flow
rates.
• Engage bypass briefly near the
end to ensure lines are diluted.
• Critical to ensure correct flow
rate to boom.
Lessons Learned from Install

21. Clean
Water
Tank
Boom
Main
Pump
Rinse
Pump
Sample Testing

23. Conductivity: We could quickly detect
salt residue in the parts-per-million
range.

24. We used food colouring to make
dilutions more obvious

26. • The Agrimetrix Dilution Calculator
suggests residues should have
been much lower than ~15-20%.
• Let’ say a sprayer has a 150 gal.
clean water reservoir and 20 gal.
left in the lines.
• Our model has 1.5 L left in the
lines, so to be fair we should have
used ~10 L of rinse water.

27. …it’s only a
model.
Remember

28. • The biggest result here is that it
took <1/3 of the time vs. 3x
rinsing… never leaving the cab.
• That translates to ~10 minutes
versus 30-40.
• Perhaps if detergent (or ammonia)
was added to the clean rinse tank,
it might be better still… we’ll
explore it this summer.

29. • Secondary pump flow rate must be
30-50% of the boom flow rate.
• Sprayers with dead-end boom
sections may not be as compatible.
• Some sprayers harder to retrofit
than others.
• Doesn’t replace cleaning.

30. If continuous rinsing is as effective
as triple rinsing and can be
performed in a fraction of the time
with less operator exposure, then
we should be modifying our
sprayers to support the method.

31. Tom Wolf
@nozzle_guy
Jason Deveau
@spray_guy
Learn more about spraying
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