sprayer control question

[gbs]

We purchased a spraymate 2 controller for and old hi-clearance sprayer we have and for some reason it is not working correctly. It uses magnets mounted to the drive hub for the travel signal, we set that using a measured distance and it's dead accurate, every setting has been has been checked several times. At first the nozzles would pulse no matter the speed or gallon settings we contact their tech support and they though our pump was to large for the system to be plumbed using the inline setup, so we changed it to a bypass system, same problem. I gave up on them and change the setting on the servo to it mid range and close down the throttle valve choking down my flow of approx. 60 gpm to achieve 70 psi on the pump side of the throttle valve which will allow around 7 gpm flow then it started working at the 20 gpa I wanted, but I can't get it to maintain the 20 gpa at a travel speed of 2.5 to 5 mph. It will and want even though I've tried more or less flow from the throttle valve and adjusted the pump speed to change the pressure on the pump side of the throttle valve. I'm at a crossroads as to what to do with this system, I have the same nozzles and boom width on another sprayer when set it at 32 psi and a travel speed of 6 mph it will deliver 20 gpa, but there is the problem i don't want to have to maintain that constant speed, and here I am killing a 60 gpm pump to maintain 70-75 psi charge pressure choked down with a throttle valve to try to maintain a 15 to 30 psi demand to operate this sprayer and the controller still can't keep the flow correct. Has any one else had this problem if so what is the fix?

 

[old smokey]

check the gallonage of the nozzles your using......may not be big enough to run the pressure and gal. per acre

 

[gbs]

according to the range chart they will run from 5.8 gpa at 18 mph - 26 gpa at 4mph at 30 psi , so if the flow is reduced correctly by the controller i should be able to achieve 20 gpa at 2.5 mph as the nozzles still produce a uniform pattern at less than 20 psi, i only need to go this slow at the head lands and water drain furrows which is a very short distance. I can't run up to these at full speed and stop then be at enough travel speed before I enter the rows again for this system to work correctly . I can accomplish this with the other sprayer but i get a little over the rate of application starting and stopping which i though this type of system would help correct.

 

[gbs]

Problem solved, this morning we changed the check valve caps from 10 psi ones to 4 psi ones, after the initial charging of the booms the sprayer didn't move 5 feet and all the nozzles were spraying uniformly even though the controller hadn't locked in on 20 gpa it didn't take it long to regulate and it would maintain 20 gpa from 3.4 mph to 6.5 mph. i was actually able to maintain this with the pump slowed down and the throttle valve maintaining 50 to 55 psi on the pump side of the valve instead of 65-70 psi, if i slowed the pump just enough to get 45 psi on the pump side of the throttle valve then i could slow down to around 3 mph and still maintain 19 to 21 gpa but that lowered my top speed to around 4.8 mph. Yesterday i was about to give up on this system but now it working fine for us.