4" Jet Pump Design

Azure

Jr. Member
Oct 5, 2020
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I designed this 4" jet pump and wanted to see if anyone saw any issues or had any feedback?

The four jets have an npt thread to allow testing different constriction diameters.

The inlet area has a male thread at the end to attach a valve for a hose.

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Rather than having your inlet water going into the chamber as shown , you need to angle the inlet line into the chamber at a angle (45 degrees or so ) this will force the water inside of the chamber to spin around inside of your 4 inch line to help prevent any plug ups AND it would keep bulging or blowing out the side of your ( metal ) tube if you use metal for you inductor tube. John "Hoser" Oates posted that years back ! God Rest his soul ! It has been said that PVC parts won't last very long......................................I had a Dave Franks 4 inch system for quit a few years with NO PROBLEM !
 

Rather than having your inlet water going into the chamber as shown , you need to angle the inlet line into the chamber at a angle (45 degrees or so ) this will force the water inside of the chamber to spin around inside of your 4 inch line to help prevent any plug ups AND it would keep bulging or blowing out the side of your ( metal ) tube if you use metal for you inductor tube. John "Hoser" Oates posted that years back ! God Rest his soul ! It has been said that PVC parts won't last very long......................................I had a Dave Franks 4 inch system for quit a few years with NO PROBLEM !

I could see that improving the performance. I'll have it printed using nylon, which is very strong and durable.
 

Nylon is soft.................. UHMW is 7 times more durable than steel and self lubricating and very machinable ! I've used it on many items on my 4 inch dredge and at home for certain items.

Cool i've never heard of UHMW, will look into it. This nylon is called nylon pa12, its much tougher. I've tried sanding it by hand and eventually gave up.
 

I assume you made this with a 3D printer ? Real nice job ! What is the orifice jet diameter's and how many jet's did you use ?

4 jets, 0.25" diameter, water inlet is 2" diameter
 

Now to check it's performance ! I did this on my 4 inch dredge using a liquid filled vacuum gage on the suction side and a pressure gage on the out put of the device and a tachometer to check the engines speed. watching these while the engine is running and the pump is sucking water ,watch the vacuum gage and record at what RPM of the engine when you get the best / strongest Vacuum reading and at what pressure reading is . This setup will show you the best setup for your device to run at. ! GOOD LUCK and I hope to see a video on your results !
 

Now to check it's performance ! I did this on my 4 inch dredge using a liquid filled vacuum gage on the suction side and a pressure gage on the out put of the device and a tachometer to check the engines speed. watching these while the engine is running and the pump is sucking water ,watch the vacuum gage and record at what RPM of the engine when you get the best / strongest Vacuum reading and at what pressure reading is . This setup will show you the best setup for your device to run at. ! GOOD LUCK and I hope to see a video on your results !

Russau, thanks for the advice. I'll work on measuring and optimizing the performance. Here's a video testing the suction.

 

Different companies use different sizes. Keene runs around Âľ" on their 2", Proline is closer to 1" on their 2" jet, but it also depends on the pump. I get better suction with the 1" jets on the Proline with either the Keene P180 or the Proline pumps because of the larger orifice. But for a trash pump, it will need an even smaller orifice, maybe â…ť". Tune your jet to the pump output. The Proline HP500 has a 2" outfeed & their jet for that pump reduces to 1â…›"
 

Different companies use different sizes. Keene runs around Âľ" on their 2", Proline is closer to 1" on their 2" jet, but it also depends on the pump. I get better suction with the 1" jets on the Proline with either the Keene P180 or the Proline pumps because of the larger orifice. But for a trash pump, it will need an even smaller orifice, maybe â…ť". Tune your jet to the pump output. The Proline HP500 has a 2" outfeed & their jet for that pump reduces to 1â…›"

Greatly appreciate the help Reed!

I'll test out large diameters for the nozzles, luckily I can drill out large diameters for the jets since it's solid nylon.
 

1/4” is too small. I’d have to look at my notes on the Vortxrex build. Curious how you are mounting the jet to your sluice.
 

In my experience with the Vortxrex system is that you need a straight pipe section after the jet as any flex in the hose fudged up the jet’s trajectory and robbed suction power. Vortxrex is a jet system designed by Dave Frank. I built a set based on the plans he used to sell on eBay. It’s basically the same as what you created but is built from laminated PVC pipe.
 

Dave supplied me with one of his Vortxrex jets for my 4 inch dredge and I loved it. When I saw that he put his plans for sale on the net I bought a set even though I already had his jet on my dredge ! I also bought 1 or 2 of his video's om his system that he was running .....
 

In my experience with the Vortxrex system is that you need a straight pipe section after the jet as any flex in the hose fudged up the jet’s trajectory and robbed suction power. Vortxrex is a jet system designed by Dave Frank. I built a set based on the plans he used to sell on eBay. It’s basically the same as what you created but is built from laminated PVC pipe.

I created an adapter to connect the hose to the dahlke float. I'm using the bw400 hose which is fairly rigid, i could strap a metal tube to it to straighten it. Thanks for the tip, i'll check on the straightness.

I did a test run last week, I increased the jet from 1/4" to 3/8" and the suction worked barely enough. I'm going to test out 1/2" tomorrow.
 

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