Posted 2/9/2019 10:20 (#7308632 - in reply to #7308598) Subject: RE: Integra, Direct Command and pressure
Southern Minnesota Between Freeborn & Wells
Quite a difference in our operating procedures. I am not concerned about getting every last drop out the tank before I refill. With your coupe and limited capacity that would be more of a concern. I would never want to "run out" in the middle of a pass as it would seem wasteful to drive back empty and then drive back without spraying to that spot.
Part of my concern about not running the tanks empty is the fear of doing damage to the pump. It doesn't take very long to take the seal out of a centrifugal pump if it runs dry. When I worked as a tech I saw the results many times.
I have used this trick to get the tanks fairly low and end up at the end of a pass. I watch the remaining tank quantity and decide if there is enough product to make another pass. If not, I may make a pass partway across the field until the volume is reduced a little less than half of where I started that pass. I then turn around (knock down some crop) and spray back. When I return to the field I move over to the next pass and pick up the stubs from the previous path. This requires turning around in the field again. Depending on the situation this may or may not be a wise plan.
With my sprayer tractor I have 1000 gallons of capacity. I never make a full 1000 gallon batch. I may make 800 gallon batches. This means I can refill before the tank is empty and still have room for the new batch. Another method is to mix hot batches int the dooryard and so the tender has the products mixed in the correct proportion. The tender holds 1000 gallons also so making an 800 gallon batch for it usually fits just fine. Then fill the sprayer to a comfortable amount. Again this would not work well with the small capacity of the coupe.
As far as your concern about leaving some in the tank and having the mixture get stronger, a self correcting approach would be to base the amount of chemical you dump in for a refill be based on the number of acres sprayed with the previous fill. As long as you don't change the rate, this would be self compensating. Example suppose you mixed up a full batch and started spraying. You got almost empty and decided to refill. Consult the acres you did on the first tank and use that to figure out how much chemical to add this time. Add that amount and top off with water.