Hypro Pump Replacement - Suggestions?

I need to replace the Hypro roller pump on my 3pt sprayer. I've not been very happy with the performance of the 6 roller pump I have and am interested in having a look-see at something else.

Any suggestions?

Thanks!
Bill

What seems to be the problem with your roller pump, Bill? Is it losing flow or pressure or a bit of both? Roller pumps will wear out after a time with the problems mentioned happening. For years we ran a 5 roller pump and when it wore out I bought a 7 or 8 roller pump (can't remember which) at the new local supply store. It never really did work to our liking, both flow and pressure were less than the 5 roller, only had it a couple years till I found a place I could get another 5 roller (hypro 1700c I believe). Only problem we had with roller pumps is they don't prime very well, need to be lower than the tank to prime right. Only other experience I've had is with a centrifical pump on our current sprayer and it suffers a bit from the same priming issues, really doesn't prime good until 50 gallons in the tank (300 gal. capacity). I find myself thinking I would like the 5 roller pump back again, especially for the flow it had (45 gallon per minute if I remember right).

You can rebuild them. The link is just one that I found, there is more out there, should be able to get the parts locally also.
pump repair

The pumps (on my second one) seem to gradually loose their ability to maintain prime. As the tank gets low, the suction gets worse. This is somewhat understandable as my sprayer is pulling liquid via a pipe from the top vs a drain type arrangement that would assist priming from gravity. This latest pump has not lasted one year. I spray a liquid volume of about 20 gallons per acre at 30 psi. The goal is drift prevention and when using Sevin XLR Plus on timothy, that's the flow rate I need too - so it works out good.

When the pump starts giving symptoms, the pressure will drop to around 20 psi. At that point I go back to the barn for a refill. When the pump gives up the ghost, it pretty much drops to near zero and the pressure gage rapidly fluctuates from 0 to 30 psi and flow essentially stops.

I'm going to rebuild the pumps I've got - 6 roller 6500 series cast iron pumps - or at least go in them and see what I've got.

Probably going to make a tow behind sprayer with a 200 gallon tank. I'm like the roller pumps when they work and the 20 ft boom/hardware fits our fields very well. But if I make up a new sprayer, I'd like to know what else is out there vs the hypro roller pumps and any feedback/experiences with them.

Thanks!
Bill

Bill, that's similar to my experience with the roller pumps too. I rebuilt a couple of them but never really got them back to "like new" performance. I think what happens is most rebuild kits only have the rollers and seals but the rotors and housing gets worn as well so there is more open space inside even if only a small amount which affects the ability to prime and pump with pressure and flow. I guess that is why I liked the 5 roller because it had so much extra capacity a little wear didn't hurt the performance I needed.

I use 20 gallons/acre as well but usually at 35 psi. The gallons/acre is more a function of nozzle size, ground speed, and pressure than pump output. Pump needs to be sized for number of nozzles at rated output/pressure plus recirculation/agitation (usually minimum of 30% if I remember right). For example if you have 10 nozzles that do .26gpm at 30 psi that would be 2.6 gallon/minute plus 30% equals 3.38gpm pump rating plus the ability to maintain 30 psi at a reasonable rpm. I am probably wrong but I sort of remember the 6 roller pumps having an output of 8gpm at 540rpm. As a side note I have never ran a sprayer pump at 540 pto speed (unless it was getting wore out). I run the pto speed to get the pressure I want and calibrate accordingly.

As for the symptoms you describe where the output drops to near zero and the pressure gauge fluctuates 0-30, that's typical cavitation. The pump can't get enough fluid in it for one reason or another (kink in hose, hose obstructed, plugged filter, or loss of prime) and effectively is pumping against itself. If you could I would try moving the suction line towards the bottom of the tank and it might help more than anything else.