Questions about a 170gpm Monarch water pump that I bought. Ok for a dredge build? :)

[NeoTokyo]

So a friend of mine was moving and he had a Monarch pump with a 5.5hp briggs motor on it. The model is BSGF-10
The pump is about 4 years old and in great shape.
In this online manual for this pump one of its suggested uses is for Mining.

I bought it for $50 bux which isn't bad seeing that they are about $800-1000 bux depending on where you buy it.

From what I have read, these are high pressure centrifugal pumps like the ones that we use on our dredges, its just with a very different (Heavier) cast iron pump case.

This pump flows 170gpm @ 30 feet of head.
The flow curve drops off sharply suggesting a restriction.
Maximum suction lift is 15 feet.
50psi at maximum head of 115'
In and out are 2"

Here is a website with some more details.
FBSGF-10 Gas Engine at PumpBiz.com

Here is the flow chart.



170 GPM at 30' of Head
165 GPM at 40' of Head
155 GPM at 50' of Head
140 GPM at 60' of Head
118 GPM at 70' of Head
95 GPM at 80' of Head
65 GPM at 90' of Head
30 GPM at 100' of Head


So my question would be, what size dredge could this run with 170gpm @50psi?
The Keene p180 runs 310gpm @ psi , Proline HP400 also runs 310gpm but at 30psi. (I thought the proline was suppose to have more volume but the info that I am finding is saying the same. I did find some info where there is more turbulence with the keene pump)

Keene's P180 are what they use on their 4" rigs.
Keene's P90 (100gpm) runs their 2" dredge.
So I am going to assume that this will be ok for a 3" dredge build as it sits. What do you guys think?
Its a little on the heavy side and I already have a 2.5" and a 4".

Now from what I can tell from looking at the dimension's and cutaways, they are the same pump housing but the BSGF-12 which flows 310gpm simply has a different impeller P/N and 3" in/out instead of 2" in/out and is powered by an 8hp briggs instead of a 5.5hp briggs. Now there is an older version of the BSGF-12 which runs a 5.5hp Briggs as well. The 3" version also has 7 less psi and has 15' head less. Both operate at the same RPM.

The 3" pumps impeller has a different vein design but the same dimensions. Its P/N is 305460005 and runs about $100 bux shipped.
So it would seem that for $100 dollars and enlarging the holes to 3" that I could easily have a 310gpm @ 43psi pump on my hands which of course then could handle a 4" perfectly.

The 3" flow chart also has a very smooth arch and looks like it would be around 360gpm at 10 feet of head.
The 2" flow chart shows a restriction and a very sharp decline at 30 feet of head, less than 10gpm is gained from dropping to 0. This would suggest a restriction, so at the very least it would be a great idea to increase the size of the inlet and outlet.

So that's pretty much it, let me know what you guys think and if you have any knowledge to add about this pump it would be greatly appreciated.

 

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[NeoTokyo]

A little more on that impeller.
In the 2" version it is a 3 vane impeller, in the 3" version it is a 4 vane impeller.
Same size.

Here is a pic of the 3 vane, P/N 305460004
I don't have a pic of the 4 vane because all I could find were .pdf files of it. Its P/N 305460005

 

[Timberdoodle]

You could run a 3" standard dredge with less than 1ft of lift above the waterline with this. Looks like 120gpm@30psi (70ft head) per the chart. A highbanker/dredge with more lift would require greater PSI to get the same suction level, so I wouldn't recommend it for a highbanker/dredge combo unless you go to a 2 1/2". Hope this helps

 

[SHoward]

It should run a 3" maxed out, a 2-1/2" with room to spare.

 

[Reed Lukens]

And you want to modify this 70lb pump? Good for a 2.5" highbanker...

 

[NeoTokyo]

Reed, that's correct.
I have more brute strength then I do money.

Actually that's the way I was thinking, a Highbanker Dredge combo.
I already have two dredges so a highbanker combo makes perfect sense.


The first mod would be free, open up the ports to 3" to solve the sharp gpm decline.
The second mod would be a little more, I ended up finding the 310gpm impeller a little cheaper than before for about $75 shipped.

 

[Reed Lukens]

With the high pressure you can work high above the river as it is for a highbanker. It's perfect as is for a 2½ because it gives you the ability to pump water up the mountain if needed. If you open it up you will reduce the ability to hit those high benches that pay soooo well

 

[NeoTokyo]

Honestly, I have never been high banking even though I had a 3" Proline highbanker dredge combo for a short time (Then I got a too good to pass up offer on it.)
I do want to highbank, our local group Shasta Miners has a newish claim that people have doing well at highbanking.

Changing the impeller and opening it up does drop the pressure by 7psi down to 43psi and 100' of head instead of 115' but it seems like a reasonable trade off for the volume.

 

[Reed Lukens]

Yea, I don't know but if you can keep the old parts, you can test it for us