Pvc Nozzle

[TheCaribbeanDigger]

Hello folks! I have many interrogatives regarding a dredge nozzle. I'm talking about the regular power nozzle. Not the jet nozzle. I have made the third (and hoping it was the last design) nozzle and here it goes. It's a 1.5" diameter nozzle with both in and out hoses. I reduced the hose to the jet from 1.5" to 3/4 to 1/2". I'm using a 9000gph 2" semi trash pump. With everything attached water does come out the exhaust hose but no suction. Little water comes out the front of the nozzle. But, when I disconnect the exhaust hose and run the dredge it has the power of a freakin' 5hp craftsman vacum! Lol! What I'm starting to think is that I probably need a bigger exhaust hose say 2"? Here are some pics...

 

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[TheCaribbeanDigger]

Forgot to mention I run it with 12' hose.

 

[winners58]

the pump is a volume pump and If the outlet is restricted it will just back up and stay in the pump
you can build some pressure by going 2" all the way to the nozzle, I ran a 3" powerjet with one, everything
had to be close to the surface of the water, almost no lift. maybe experiment with larger tube going into the
nozzle to take advantage of the water throughput. I also adjusted the top end of the motor to run at the full 3600rpm.

 

[TheCaribbeanDigger]

I saw this video on youtube, this guy used a 9000gph semi trash pump on his 2" pvc nozzle and it worked great! Now I'll be improvising a 2" nozzle with 2" discharge hose. Let's see what happens.

 

[winners58]

seems like it should work good, maybe the bend going into the nozzle is too flat,
have heard you can fill it with water and plug both ends then bend it.

 

[russau]

or fill it with sand.

 

[TheCaribbeanDigger]

or fill it with sand.

To tell you the truth I dis fill it in with sand! J don't know why it happened but I dont think it stops the flow to a point to be worried. https://youtu.be/sO6x2DM2GfY
Check this video out. It works great I'd say AND he's using a harbor freight semi trash 2" pump. I'm planning on using 2" pvc instead the 1.5" https://youtu.be/ftwlQRaf0-U
Now this other pvc nozzle works with a 12v 3700gph bilge pump! Definitely my 9000gph 2" 45.7psi water pump should work more than great!

 

[TheCaribbeanDigger]

And another thing...in the 12v dredge he's using a short jose. I'm using 12' of hose. I'll shorten it to half say 6'. Lets see if that helps!

 

[SunshineMiner]

I gotta chime in. DO NOT RESTRICT YOUR PUMP TO YOUR NOZZLE. If you have a 2" outlet, run 2" all the way to the nozzle, have 1.5" outlet? run 1.5" outlet to the nozzle.

You guys think putting a smaller hose on the outlet raises the psi? You also are not taking into account friction loss. In a 12v or even a trashpump setup you need all the unrestricted volume/PSI you can get. That means unrestricted flow to the nozzle UNTIL you neck down for the jet. This will give you max suction. IF YOU CAN, keep your pipe as big as possible before necking down to your jet.

Digger - The video you posted he has the right idea. The only problem I see is that he has it restricted so far back. A 12v pond pump 3700-4000, doesnt matter, doesnt have the PSI to keep up with restriction like that. What I did for mine, was where he has his T for his nozzle, that should be the only place its necked down. From there, going back to the inlet pressure line, use PVC reduction fittings, or 45* connectors and heat them up, press and glue together so that it curves backwards. I have a video I'll post so you can see what I mean.

 

[TheCaribbeanDigger]

This is my current setup. It's all 1.5" in diameter. Both hoses and the nozzle itself. If I take out the outlet hose from the nozzle it sucks like a beast. But when I re-attach the hose it does not.

 

[SunshineMiner]

Alrighty.. as promised, heres a small video of it. Unfortunately only the first 7 seconds show the nozzle, and even then sort of underwater, i apologize. I'll b getting out this weekend i'll get a video of it. Now, as EVERYONE has probably already said, invest in a metal one. I plan to this summer. Why? I already broke my first one(the one in the video ironically). Probably already due to outward pressure already forced on the pipe from the inside, it split down the very center of one of my 45 elbows. It also doesnt help i was probably banging that sucker around XD



So, your "jet" is what.. 1/2" now? So you took a trash pump that only has a max PSI of say 55(im being generous, i think mines 45). Thats full bore, AT THE OUTLET. Thats not counting hose, bends, or restrictions. Now, taking into account fluid dynamics, you get a thing called friction loss along the length of the hose. This robs the water of velocity, kind of like your damper in your dredges? it slows water down right? well, that same force is exerted all along that hose. So, you've taken a 2" and restricted it down to 1.5". Now your pump is instantly pushing that water through a smaller hole and having to push the entire length through a smaller hose, which equals more friction loss as there is more surface area for the amount of water in the hose to "grab" on to, again, robbing your water of precious velocity through the hose. Then you take it to 3/4 along a good length, and finally to that 1/2 where it doesnt have a whole lot of pressure left as its lost most of it through all those restrictions and smaller diameter hose.

Take 2" pipe, from your pump, too your nozzle, there, you can only neck it down to about 1" to 3/4" I'd say maybe 7/8". But the reason for this is you NEED volume to push the water up the hose. You don't have PSI to play around with. You're not using a pressure pump or a dredge pump.

So heres how I make a nozzle.
For the suction part itself, i start out with a 2" ABS T, or one of these: 2 in. ABS DWV H x H x H Long-Radius Tee-C5812LHD2 - The Home Depot
Looking at the part on the website its oriented "top" where your "jet" will enter, to bottom where your hose to your sluice will go with that suction being the long turn.
From there, take a 2" to 3/4" reducer and build out the front going back to the hose coming from your pump.
What I did with the one in the video, was as above, and then from the 3/4", get a 1" 45, a 1.5" 45, and a 2" 45. Take the 1" 45, heat up one end with a heat gun, and then when its pliable, stick the 3/4" 45 in there and make sure you glue it with pvs/abs glue!! Keep doing this for the 1" -1.5", 1.5"-2". And use pipe as necessary to build it up/support. Its pretty darn strong when you use PVC glue and get it all tight. My issue was I banged on it too much due to clogs it sucked so hard :P
You'll get the general idea after my video. I'll get another one this weekend if I can.

 

[TheCaribbeanDigger]

I just love DIY projects! The other nozzle worked I'd say like a 65-70%. It didn't had the suction I hoped for. But I did this other design which I'm hoping it'll work. I saw some other similar designs on the web. Lets see what happens!