6" dredge dual quad jet..

[principedeleon]

Hey guys, i just remodified my quad jet to dual inlet for less weight and more GPM output.. I have tried to have to have both pumps pushing water but one pump shuts down the other pump from suctioning.

I have some pictures of the dredge ..
Hope someone help me fix this problem without having to make another jet.

 

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[Reed Lukens]

You need vent holes in the top of those drums to keep them from sucking in like they are in the pic. Have you tried bringing the rpms up slowly and together or is one pump way bigger than the other?

 

[principedeleon]

Yea.. I probably put valves like my last ones and fill them up with a air compressor. It has helped me pop it back out in place and keep it that way .

But The pump on the left is a 7hp engine with a P350 pump and the one on right is my 8hp ke201 .

I have tried raising the RPMs slowly and One pump sacrifice his output for the other pump.
If i was to accelerate the 8hp pump it will have the the other pump pumping water out the other pump inlet loll ..

I was thinking trying to have both pump enter through the 3" inlet but idk if i still going to have the same problem..

The safe side would be separating both jets of water separately but i was hoping for a better solution.

 

[Reed Lukens]

Yes, you're going to have to separate them because the 201 is a high pressure pump and the 350 is high volume, so the 201 will blast through the 350 every time. You could change out to 2 - 350's but separating them in the jet would be the easiest.

 

[Timberdoodle]

You might be able to find a match in the pump curve of each individual pump using a pressure gauge on the jet housing and a tachometer if you have one.
Connect one pump at a time to the jet and cap off the other inlet.
Run up first pump to 20psi at the jet housing and note the rpm's.
Disconnect and attach second pump and repeat for second pump noting rpm's
This should provide a starting point for each pumps separate rpm setting providing equal flow/pressure in the jet housing.
Connect both pumps to jet and set rpm's and note final combined psi reading.
repeat this procedure for psi settings until final desired combined psi is reached.
Hope this helps

You may have to start with a lower initial psi than 20. It depends on the size of the individual jets and whether one pump can achieve that much pressure on it's own.

 

[principedeleon]

I would be harder finding me a tachometer here in DR then changing the jet.. I was thinking if i could have both pumps jets go through one 3" pipe inside the jet housing ..

 

[Timberdoodle]

You could try a wye going into a single 3" feed but going to 4" would be better. your still going to want to set the pumps close to matching.
If you don't have a tach, just use the pressure gauge and your ear and figure a way to mark the throttle setting.

What were your final orifice sizes for the jets? This will help determine the flow speed into the jet and sizing of the feed.

 

[principedeleon]

It was 4 3/4" holes and i cant hear one after i turn the other one on ..

 

[Timberdoodle]

It was 4 3/4" holes and i cant hear one after i turn the other one on ..

Ok you will be delivering approx. 400gpm @35psi in the jet housing. This results in 18fps feed rate of a 3 inch pressure line which is in the upper range before friction loss becomes too great. It will probably work but be on the edge. 2 separate feeds into a wye then into a 4" feed would be 10fps which is good for a pressure housing like you are using.

The ear thing was mentioned for initial setting of each pump separately and getting a rough sense for the rpm and the difference between the pumps. Just mark the throttle for a matched psi.

 

[principedeleon]

6" dredge dual quad jet..

Ima give this a shot and remodel the jet again..

Thanks all ya for the help !!
I'll keep ya updated..

 

[Reed Lukens]

The problem is that the pumps don't come close to matching so keep it simple. You have a 2" pump and a 3" pump. Best to just put in separation plates and honestly with a 201 you really only need a 1" jet total. If you would have simply made a jet for each pump, you would have been running already. Still you need the right opening size for each to get the most out of them.

 

[principedeleon]

So this means i would be better off making the jet all over for better performance ??
I dont want to put in the seperation plates or changing the inlet which by what Tim was telling me i need to try to have both pumps match and the curve be far from eachother and makes me not use my pumps to a full potential ..

So making a new jet sounds like a way to go but i want to make it simple and efficient as possible.. so im open to any new plans on how should i run both pumps and opening size of the jets for the best performance of each pump.

Its raining over here so im not so desperate to head in the water right now and the river im targeting is running low in water.

 

[Timberdoodle]

4 jets are more efficient than 2 because they are inducing more area, I would keep them. As far as the total orifice sizes, 2 3/4" jets is only about 10% larger than a single 1" jet so the 201 should have no problem supplying half the flow/pressure.
The key is finding the matching rpm's for the volume/pressure. You could install a ball valve on the p350 and regulate pressure/volume manually for fine tuning also after setting rpm's close.
Just trying to think out of the box to try and help you find the solution without adding much cost. A couple cheap small motor tachs and a pressure gauge would make tuning these to each other very simple.

 

[AuTSaurus]

I’m certainly no expert, but I think I see what you are trying to do, and I think I see the problem.
I think you are trying to increase the volume and pressure at the “internal” output ring of the circle jet, correct? If so, I think the problem is with the inputs.

Two pumps works good on a dual straight jet log, but I think that trying to feed two, separate, powerful inputs of water into the same chamber of the circle jet are interfering with the desired result, due to unwanted turbulence and the inputted water is flowing much easier back out of the other input tube, because water always goes to the path of least resistance.

The larger volume of water and different pressures coming into the chamber automatically flow to the larger and easier opening, rather than being forced through the “circle” opening.

I think if you got rid of one of the inputs on the circle chamber, then made a single “Y” going into the chamber, you then have your two pumps combined, working together as a single input, and they cannot cancel one another out.

You will probably want to increase the diameter of the input pipe, immediately after the Y where the two pump flows come together, by a little bit, but I definitely would not double it in size.

Like I said, I’m no expert, but I think this would help to solve your problem.

 

[principedeleon]

I placed two separation plates to divide both pumps. I haven't went test it yet but i believe it will work well..

 

[AuTSaurus]

That may solve it, testing will surely tell. Just remember that you still have two, separate internal chambers now,
each having different volumes and pressures from your different pumps, that may feed unevenly into and through the
circle orifice. I don't know if that will affect the building of the suction column, or not.

Please keep us posted. Nice, building your own, and trying to see it through!

 

[Reed Lukens]

That may solve it, testing will surely tell. Just remember that you still have two, separate internal chambers now,
each having different volumes and pressures from your different pumps, that may feed unevenly into and through the
circle orifice. I don't know if that will affect the building of the suction column, or not.

Please keep us posted. Nice, building your own, and trying to see it through!

Yes, it will feed unevenly but that can be compensated for by stacking the jets vertically. You will usually see the flow coming out harder on one side of the flare with a dual jet and different pumps, but you see any single jet system come out harder also depending on if they put the jet on the top or side. When I ran a Keene, I would put the single jet at 45° or a little more from top and it worked really well for a single jet but the dual jets are a lot better. You can compensate for this on your quad jet buy running the jets at 90° making one pump run the top 2 jet ports and then the other pump runs the bottom 2. This way it will flow evenly out of the flare and into the box plus you can run both pumps maxed out and have an even looking flow in the box where it counts

 

[Timberdoodle]

That will sure cure the problem with the pressure differences causing backflow between the pumps and the plate locations make it easy to follow Reed's great advise on stacking the jets vertically.

 

[principedeleon]

6" dredge dual quad jet..

I do have one pump suppling water to the top two jets and one to the other bottom two jets. But im not really understanding on what would i need to do to stack the jets vertically.



Does it mean changing both inlets In a 90 degree ? like the dalhke jets Instead of coming in slanted like a 45 degree angle ?

 

[rebel003]

He means one jet feeds the top two ports and the other jet feeds the bottom two ports. not changing the input angle. Sounds like you have it correct.