collapse


* User Info

 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?

* Who's Online

juu907kodibear

Dot Guests: 223 | Dot Users
Dot Hidden: 0

* Board Stats

  • stats Total Members: 13016
  • stats Total Posts: 131036
  • stats Total Topics: 18330
  • stats Total Categories: 5
  • stats Total Boards: 48
  • stats Most Online: 814

* Advertisers

Mining Claims
Gear Pan
The lil Gold Spinner
BC GOLD
The lil Gold Spinner
The Pocket Sluice

Author Topic: 3" hydro nozzle (custom DIY)  (Read 18086 times)

0 Members and 1 Guest are viewing this topic.

Offline Mesojdm

  • Member
  • **
  • Posts: 7
  • Kudos: 1
Re: 3" hydro nozzle (custom DIY)
« Reply #10 on: May 29, 2012, 04:48:52 PM »
I am not sure the pressure, but the specs are:
Maximum Overhead Lift: 92-Ft.
Maximum Suction Lift: 26-Ft.
Maximum Flow Rate: 158 GPM.
Max Output: 7.0 HP / 3600 RPM.
Max Torque: 13.2 Nm / 9.7 ft/lb.
Displacement: 208cc, Bore: 69, Stroke: 55.

It will not feed any gravel at all at highbanker level, but it will produce enough suction on my hand and did suck up all the water in the hole(as seen in picture).
I was thinking maybe it is my jet located on the nozzle (1.25")????

Offline ebuyc

  • Weekend Prospector
  • PPT Invited
  • *****
  • Posts: 2017
  • Province/State: Spokane Valley, WA ; USA
  • Kudos: 54
  • 12 yrs of union-demolition, show me the bedrock!
    • My YouTube Channel
Re: 3" hydro nozzle (custom DIY)
« Reply #11 on: May 29, 2012, 05:35:02 PM »
I am not sure the pressure, but the specs are:
Maximum Overhead Lift: 92-Ft.
Maximum Suction Lift: 26-Ft.
Maximum Flow Rate: 158 GPM.
Max Output: 7.0 HP / 3600 RPM.
Max Torque: 13.2 Nm / 9.7 ft/lb.
Displacement: 208cc, Bore: 69, Stroke: 55.

It will not feed any gravel at all at highbanker level, but it will produce enough suction on my hand and did suck up all the water in the hole(as seen in picture).
I was thinking maybe it is my jet located on the nozzle (1.25")????

9K GPH is ok for a 3" nozzle - maybe a little on the low side but adequate (8Kgph is the recommended min).

Since the hoses are under 20' then I would try a nozzle reduction for the venturi chamber.
Cut out a section and either use thicker walled pipe or slip a smaller pipe in (or both). I would shoot for 7/8" Interior Diameter +- 1/8" (try 1" then 3/4" maybe?)
Obviously the lower the hopper the better, but you should be able to dig well below that level!

My 2 bits...

Did someone say       

Offline Goldcrow

  • PPT Invited
  • *****
  • Posts: 1183
  • Kudos: 3
Re: 3" hydro nozzle (custom DIY)
« Reply #12 on: May 29, 2012, 08:15:18 PM »
I would try a higher pressure pump - 92 ft. of head x 0.434 = 40 psi. Before you re-do the nozzle I would borrow/rent a better pump & test it. Remember, that 40 psi is max, when everything is perfect -figure hose & fitting losses, might only have 30 psi.
Work smart..and hard

Offline overtheedge

  • PPT Invited
  • *****
  • Posts: 771
  • Kudos: 36
Re: 3" hydro nozzle (custom DIY)
« Reply #13 on: June 01, 2012, 09:20:18 PM »
I think goldcrow nailed part of the problem. You don't have enough working pressure to get the lift you need. Another problem is the orifice diameter. Usual diameter of the orifice should be about 1/4 the diameter of the nozzle. So I'd try a higher pressure pump first and maybe change the orifice to 3/4" if the pump doesn't solve the problem. I tend to think that your actual working pressure with a 1.25" orifice is probably closer to 20psi max and might be a bit lower.

If your pump came with a pump output curve in the instruction book, you can get an idea by disconnecting the hose from the sluice and filling a bucket placed at the same level as the head of the sluice or highbanker. Time it and figure out how many gpm you are getting and compare it to the curve to determine the working pressure.

Lift capacity is dependent on two things, injected water mass and velocity. Velocity is dependent on pressure (momentum) and orifice diameter.

What takes place in a suction nozzle is the injected water must push whatever is in the hose to its outlet. The suction isn't really suction, but rather is atmospheric pressure on the water level you are dredging from pushing water and material into the nozzle to replace what got pushed up the hose. Pascal figured out that water doesn't compress and by the same token it doesn't want to uncompress aka vacuum.

So in your case, you have volume, but not enough pressure to push with. You have really two options. Increase volume with a much larger output volume pump or increase pressure with either a higher pressure pump or decreasing the orifice diameter. The Keene 3" pump runs about 60psi (135-140' of head) and 150gpm from a catalog I'm looking at.

Looking at your nozzle design, it appears the most practical way to replace the orifice is with a slightly smaller pipe with the orifice welded on and slipping it into the existing injection pipe from the nozzle output end. For testing, you can hold it in place with a sheet metal screw. Once you get it tuned, pull out the screw and tack weld the insert.

I've run 2" nozzles with 30gpm/40psi pumps, but I ran negative lift. In other words, the sluicebox was lower in elevation than the nozzle. Effectively I was siphon dredging with a small pump to get it primed.

Keep in mind that the higher the lift desired, the greater the demands are for higher water velocity injection with enough volume.

Reducing the diameter of the material you lift can sometimes make a major difference. Big rocks (+2") take more push to get and keep moving than small pebbles (-1/4"). If I see a 1/4" nugget, I'm picking it up and putting it in my pocket. I refuse to completely trust the sluice with a nice nugget when I'd rather grab it with my hand.

Hope this helps. Venturi science isn't well documented.
eric

Offline ebuyc

  • Weekend Prospector
  • PPT Invited
  • *****
  • Posts: 2017
  • Province/State: Spokane Valley, WA ; USA
  • Kudos: 54
  • 12 yrs of union-demolition, show me the bedrock!
    • My YouTube Channel
Re: 3" hydro nozzle (custom DIY)
« Reply #14 on: June 02, 2012, 08:02:25 AM »
Overtheedge shows his experience again! Thanks for that excellent response.

I run my 2.5" hydroforce nozzle on a Champion 4hp 158gpm trash pump just fine and have dug at least 5' below the crash box inlet. Supply line is reduced to 1.25" and 2.5" return.

163 cc CHAMPION OHV Engine
Inlet dia.: 2" NPT
Outlet dia.: 2" NPT
Total Head: 98'
Suction Distance: 26'
Maximum Delivery Volume: 158 gal/min
Maximum Solids Diameter: 3/4"

I admit I would like a high pressure pump to increase my suction and/or hose length - bigger rocks will plug my system up easily though - why I mentioned avoiding them in previous post. A bar across the middle of the nozzle opening really helps! Seems like a 7hp engine could handle a bigger pump - as Goldcrow points out the pressure is on the low side.

So let us know how it goes (no pressure there - punny) - very interesting stuff to me!

Did someone say       

Offline ebuyc

  • Weekend Prospector
  • PPT Invited
  • *****
  • Posts: 2017
  • Province/State: Spokane Valley, WA ; USA
  • Kudos: 54
  • 12 yrs of union-demolition, show me the bedrock!
    • My YouTube Channel
Re: 3" hydro nozzle (custom DIY)
« Reply #15 on: June 02, 2012, 09:51:43 AM »
It just occurred to me another way to increase your suction is to add a second pump and a power jet if you dont have a bigger pump. Running the power jet inline somewhere, probably close to the HighBanker. You should have the best of both worlds this way?! I could be wrong of course - two trash pumps might not work well together to produce more pressure...

I was thinking about this last year since I have the 2.5hp honda with the Keene P90 pump on it and the Champion trash pump. But I have not got around to building a power jet as there is not enough water on my claim for dredging... so many projects left undone  :(

3" Keene power Jet w/2" jet

My 2 bits again...
Did someone say       

Offline Mesojdm

  • Member
  • **
  • Posts: 7
  • Kudos: 1
Re: 3" hydro nozzle (custom DIY)
« Reply #16 on: June 03, 2012, 11:14:15 PM »
overthedredge, and others-thanks for all the info!
I have re-modifed the jet to a 7/8" ID like someone suggested. It will not be more volume, but hopefully more pressure to create a better venturi effect. Also with the Same pump.(btw, did a rest in the backyard pool, and it will do ~150's GPM.) So if this fails, I will look into a new pump.(keep this trash pump to run a mini washplant or something)


Also, while on HYDROFORCE'S website, their HF300 (3" model) does not mention about a PSI requirement. Rather, it mentions just a GPH requirement. (~9000GPH min.)

I will try it out next weekend and let you guys know. My plans are only to use it until the water warms up enough for some dredging. If it ends up wokring out, maybe use this along side a river dredge.

just a quick job with some antirust underbody coating <-laugh->

Offline ebuyc

  • Weekend Prospector
  • PPT Invited
  • *****
  • Posts: 2017
  • Province/State: Spokane Valley, WA ; USA
  • Kudos: 54
  • 12 yrs of union-demolition, show me the bedrock!
    • My YouTube Channel
Re: 3" hydro nozzle (custom DIY)
« Reply #17 on: June 04, 2012, 05:23:47 AM »
Also, while on HYDROFORCE'S website, their HF300 (3" model) does not mention about a PSI requirement. Rather, it mentions just a GPH requirement. (~9000GPH min.)

I bet you will have some more suction - let us know when you find out! The midwestprospector recommends a min. 8Kgph pump for the 3" model btw.

Good job on the jet mod! It sure would be neat if someone figured out how to make a variable jet! Like a brass hose bib nozzle or something... thinking aloud again - oops.

Did someone say       

Offline soverey

  • Member
  • **
  • Posts: 2
  • Kudos: 0
Re: 3" hydro nozzle (custom DIY)
« Reply #18 on: July 15, 2012, 06:12:45 AM »
Congratulations on the build  :)

Offline Stoven1

  • New user
  • Posts: 1
  • Kudos: 0
Re: 3" hydro nozzle (custom DIY)
« Reply #19 on: July 24, 2012, 07:44:08 PM »
Sure would like to know if the 7/8 inch inlet helped!

 


Gear Pan
Gold Rat