underwater sand blower / pump

[drhans]

hi, i looking to home-built some kind of pump or blower to move sand from one location and dump it, lets say 30 feet away from the location to be cleaned, the operation will be underwater, at a depth of approx. 30 feet max.

does anyone have plans or suggestions how i could built such apparatus ?

i have been researching on the venturi system, but im not sure if it may be suitable for this operation.

i would be very thankful for any help

 

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[littleneckhalfshell]

seems to me a venturi system would work, sort of like a dredge, but you would not have to bring it to the surface. You could have the pump up at the surface (for the high pressure water jet for the venturi) Unless you want to remain 'undetected', then that is another whole can of worms.

One major concern though when moving sand underwater is visibility can quickly become an issue.
You didn't say if this was a river/stream situation where you could have your discharge down stream, or if it is a lake/bay/ocean where current may or may not be present.

 

[russau]

a venturi system would work just fine. just make sure your dischargeing yous material downstream from you and youll need to anchor this tube by either tieing it off or makeing a damper for the exit end of your discharge tube to dampen its thrust from the water......otherwise this will take off like a bullit from you.what size of hose are you thinking of useing?? and like was asked, are you using this in a stream, lake,ocean?im makeing a 5 inch "hog" tied off to the side of my 4 inch dredge to hog out the overburden from the bottom of the stream.

 

[drhans]

the operation will be taking place in the ocean, but in a calm bay, so im not really worried about currents etc.
im also not worried about getting detected

please see the pictures attached and tell what you think and if this may work.
This is a jet powered inflatable jetski with 5 HP running on gasoline.

 

[russau]

obviously your going to at the surface with this engine and having a hose going from this to where your moving(blowing) material from.Mel Fishers crew used something like this except they developed a way to divert the thrust from the boat engine to aim its thrust downward into the area they wanted to search. your wanting to go to a depth of approx. 30 ft . ....unless you attach a hose to this output i dont think youll get enough energy from this to get to the area youll be wanting to move material from. but at a shallow depth it may work. but with a venturi system you could have the engine/pump above and a 2 inch line going down to the venturi system and you could use a 4 or a 5 inch suction hose to move material into a wire cage at the venturis output. all of his would be underwater except for the engine/pump for obvious reasons.and you could run a hooka air system off that eng/pump combo for $$$$ savings over a air tank. but please remeber to watch your underwater time/depth!!!!

 

[bigfish31]

I think you'll need a higher pressure pump.

 

[stryker-one]

How you going to keep it in one place--I mean when you start moving water you are going to start moving the jet too?


Stryker

 

[drhans]

now i measured the outtake of the jet and it has a wide of 3.5 inches, i was looking to convert it into a 2.5 right at the pump, and to make the intake hose a 3.5, what do you guys think about that ? is the thickness of the hoses actually important for the ventury system to work properly ?
isnt there some kind of formula, with which i could calculate the amount of sand/water i can displace in a certain amount of time ?

i have tested the jet and when i lift it out it does displace at least 10 gallons per second, thats what i have been able to estimate

the jets impulsion works by the water being pumped out tru the hose, which will be underwater tied to a wire cage, i dont think there will be any displacement happening as the impulsing water stream is diverted, if thats not the case we can always tie up the whole thing to a boat or anker it.

thanks for everyones help !!!

 

[russau]

for using this as a blasting hose,i would keep your output hose full size and reduce it at your nozzel end. this will keep your pressure up and wont restriect the water flow at all. you do realize that your going to be in a sand storm while blasting this sand dont you!

 

[Hoser John]

So easy it's crazy--all you need is a jet,2-hoses,pump,and a boat anchor to keep the jet inplace. John

 

[boogeyman]

The old guys used to use an aparatus that diverted the wash off the prop down instead of thwords the stern. If you have access to a outboard, you could get a galvanized air conditioning duct 90 weld up some angle iron to hold it to the transom and allow it to be swung up out of the way of the outboard.

Another possibility is to use a pump with a pressure nozzle. I used a setup like this back in the 80s to move a large amount of mud. Used a nozzle from a fire hose. Welded the tip and redrilled it with an oblong shape. Worked real good! Like stated in the above posts visibilty will go to the equivalent of pea soup.

 

[drhans]

i do not want to blow, i actually want to pickup sand and blow it tru a wire cage a couple of feet away from the site.

im planning to use the venturi system which works as shown at the graphic attached.
The sand will never come in contact with the pump, gravity and suction will do there job.

your thoughts please

 

[boogeyman]

Looks like you've got it! Just run a hose from the discharge end of the jet tube to a seive.

 

[Hoser John]

Yep,thats what i said--ssssoooo easy-John

 

[drhans]

i started to work on the jet pump today, the first part was to divert the stream downwards, i think we made a very solid adaptation so far.

now some new doubts came up about the venturi system.

Should the Y piece where the venturi is going to happen be placed close to the bottom where the dredging will be taking place ?
as on the picture it has an approx. 3 feet tube going straight down, but we will be working at a depth of approx. 10 - 13 feet.
so should we rather get a flexible hose of approx.13 feet, cut it at approx. 9 feet and put in the Y piece there ?

sorry for the bad English

 

[bigfish31]

You can feed the jet into a larger tube to increase the volume if the pump has enough pressure and flow.

 

[fortunate]

what depth do you want the 'cage' at? at 10 -13 feet working depth ..it does'nt matter the depth of the y...
but, if you go to 20-30 feet..you need the y much deeper..

I dive for gold with this system in the 40 mile river system ansd other places in alaska with my 8 inch dedge for gold
Obviously , you are looking to salvage artifacts and or coins...this will work...but, in zero ocean current \, you will quickly be working by braille..happy hunting..fortunate

 

[russau]

as you have the "Y" fitting positioned ,you need to reduce the inside diameter of the 3 foot length pipe to about 3/4 inch.(assuming your using a 2 inch pvc pipe.) this will increase suction on the upper right portion of the "Y" and your discharge will be the lower end of the "Y".for a 2 inch pipe youll need about 100 GPM.a three inch youll need about 160 GPM and on a 4 inch line youll need about 300 GPM.hope this will help you in figuring it all out.

 

[drhans]

the discharge end of the jet has a 3 inch exit, we reduced it to 2 inches to guarantee optimum performance, as im not quiet sure how much this little jet could handle.

the depth we will be working on is definetly not deeper then 15 feet, not 30 as i had thought earlier.

thanks for everyones help so far, i will try to adapt a pool cleaning hose to get the system working over the weekend