[AT] OT--foam marker for sprayers

[Greg Hass]

I have worked on my cousins foam marker many times but have not in 6 or 
7 years so I'm a little hazy on a couple of things. First you mix water 
and the liquid in the tank. The amount of foam liquid you put in 
determines the density of the foam (it does not foam up in the tank); we 
then added dye to the tank, usually pink, to make it easier to see in 
the field. The mixing chamber was like a short pipe, maybe 2 inches. The 
solution was pumped in through a single sprayer nozzle, such as a 10 
gallon tip. The pump is the same pump that is used on most 10 gallon 
lawn sprayers. An air compressor (ran off the tractor battery) then 
added air and pumped it through a 3/4 inch hose to the end of the boom 
and hooked to an elbow with a sort of upside down funnel except that 
after it flared out, the sides were straight for three inches and then 
had a half inch lip on the bottom, the lip would hold back the foam 
until it got heavy enough and then the "blob" would drop. The air 
compressor had a speed control on it and the speed determined the amount 
of foam and thus the spacing of the "blobs". He had bought the unit used 
and the second year he called and said the air compressor wouldn't work 
and they thought it was the speed control switch, which I also 
determined it was. 2 hours and $150 later we had a new  switch, which 
was smoking and burned up after only 20 seconds. After 30 minutes of 
studying wiring diagrams I found that when they put the sprayer on the 
tractor, they hooked the wires up to the battery backwards. I guess 
those switches for speed control are very polarity sensitive. Another 
$150 and we were going again. The next year he called with the same 
problem. As I walked around the sprayer to look at the battery, he got 
mad and said he had marked them and that wasn't the problem. I put my 
hands up and said, take a look. Even though he had put tape on the wires 
and put a big + and - sign on them he had still hooked them backwards 
and burned up the switch. He never did get a new switch, just drove by 
guess for a year and then went GPS  which he still uses and with the 
same sprayer. As for the divertor  valve, it always gave trouble, he 
never got a new one because of the cost, so we used it the last two 
years with foam coming out of both ends. I had it apart several times 
and it is sort of a gate valve as it is handling foam and not liquid so 
I am not sure that a garden irrigation valve would work.
I know I have rambled on a bit and hope I have helped and not 
discouraged you. As you can tell, most of the problems were human error. 
My relative can be hard to work with at times. One time he will spent 
tons of money on something and if he gets mad wouldn't try and fix it at 
all. Good luck.
        Greg Hass