Hello All,
I have a couple of questions about centrifugal pumps for dredging. My friend Rafael has Keene aluminum pump 3x3 inches for both intake and out. Is that too big of a pump to use for a 4 inch suction dredge? Is it also too big for a 6.5 hp engine?
Replies
The best thing to do would be go to Keene's website and see what motor works with that pump. I have a P-350 on my 5'' dredge and an 8hp motor is barely enough. I used to have a 6'' with a P-400 and it took a minimum of a 13hp motor. The P-400 would fit on my 8hp motor, and they look the same but the impellers are different and the 8hp won't push that p-400 enough to work.
I have a 3x2 gold grabber pump on a 5hp Honda and I've had suction issues that I think are the result of not having enough motor to get the pump to ideal rpm. If I had a 6.5hp I suspect it would do the trick but a 3x3 on a 6.5 might produce similar issues. Only time will tell. I have suction but it bogs way too easy. I'll be swapping it out for a P180. If you have problems you may want to look into a different pump since I'm reading you don't want to go up in motor size.
Rob the following two links might help. http://www.onestopfire.com/head.htm and http://goldprospectingforum.com/viewtopic.php?f=28&t=1296 Hope they help you in your selection process.
rob you will have to go to a bigger motor if its an externial thread impeller keene on their bigger pumps could be eather a 3/4 inch or a 1 inch threaded hole in the impeller if its a free standing pump you can have a coupling made so you can use any motor you want with the pump might help if you can post a few pic s of it i did some research on the keene pumps the biggest is a 4x3 inch pump nuthing that is 3x3 should be a name anr or number on the houseing that will help to
It's going to be a 1" shaft with 11hp to 16hp minimum. Need some pics of the case and impeller or a model number. You should call Keene and ask them. If the impeller is narrow with maybe ¼"slits then it is a lower hp. maybe down to 8hp but still it will be a 1" shaft.
Ok, Thanks for your input. I will check.
no should work great shouldnt have to throttel above 1/2 throttelyou must be talking 1 of the newer keene pumps or a proline
Actually the pump is from the 1970s when a friend brought it from the U.S. to be used here. Rafael only used it two or three times. I think the shaft hole on the pump might be too big for the 6.5 hp engine though. I am trying to avoid getting a bigger engine because of the heavier weight. I did find today a 6 hp engine with a 2x2 inch pump system with 90PSI that I am considering. Lightness and portability are part of the qualities I am looking in a motor and pump combo. Thanks for the input.