HELP! with a hand dredge!!

[Sackett]

I have built a hand dredge, through trial and error I am getting there, but still encountering some problems and I know some of you have already been where I'm at and know the answers!! Here is what I have and my problem...I have a sucker tube of 1 1/2" pipe, with 1" handle. On the end of the sucker tube I have a Y (which is removable, so as to accommodate another Y for 2 different set ups) the 1st set up has an 1 1/2" check valve on the suction tube end, with a collection container attached to the other end of the Y, it works great! My problem is with the 2nd set up, here I have a Y attached to the sucker tube, on the suction end is a 1 1/2" check valve, then off the discharge end another 1 1/2" check valve with a hose attached which goes to a bucket...I can pump WATER like crazy!! but every time I pump material after the 1st pump the discharge check valve will hang open with a small rock or even particles of sand and of course then there is the loss of suction from the loss of pressurization... I have the flapper hinge at the top of the pipe as I learned any other position would cause loss of pressurization from the flapper "drooping" open... How do I solve this problem of clogging up with tiny small rocks Should I go to a 2" check valve for the dischargeall help will be appreciated!

 

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[TheHarleyMan2]

Is the check vavle flap where it is mounted on the inside at the top of the check vavle? What I mean is if the suction pump is upright, is the flap of the check valve mount at the top inside of the check valve? It could be that you are working at an angle which would cause the check valve flap not to seal.

 

[Sackett]

Yeah Harleyman I have it at the top...The 1st time I did not have it at the top and it would not pump anything. I learned as I went and turned it to the top...Tested it in water, pumped water like crazy...went to the creek, stuck it in the water, pumped bucket half full of water, then stuck it into the gravels and sand AND...one pump and clog,,,cleaned out,,,pump,,,clog,,,,tiny rocks hanging up in the flapper?? I don't know why,,,,

 

[TheHarleyMan2]

I think what the problem is with your dredge is that you are sucking too much material and not enough water to move it as well. What I found on my hand suction dredge I made, when I tested it out. Pumping water it worked like a champ!

I then dug dirt from the flower bed. Yes good old top soil, some small gravel etc. It plugged up the nozzle and clogged up everything, because I was trying to suck fine dirt and not enough water was getting sucked up as well.

So what I did to relieve the problem, I thought about the flow jet on a suction dredge nozzle where water gets injected at the nozzle to help from clogging up the hose and move the material.

So on my suction nozzles, (all of them, 1/2, 3/4), From the end of the nozzle I went up the nozzle about 2 inches and drilled a 3/16th hole for the 1/2 nozzle, and a 1/4 hole for the 3/4 nozzle. Also make sure close to the tips, (almost to the end), of the nozzles, that you have a screw going through the nozzle tube. This will also prevent bigger rocks from going into your pump that could cause your check valve to be locked up.

That solved my plugging problem real quick!! By that while I am sucking the material I am also making sure enough water goes in with it to prevent the nozzle from clogging. Now before I get to full up stroke on the pump, I pull the nozzle up a bit to just suck in more water to help keep a fluid flow of the material in the lines and the tube. Then I pump the material into the bucket. If you do not have enough water flowing through the system you could get some bigger rocks etc, preventing them to go through the valves causing them to stick the valve open.

I have pictures of it posted on the Homade Equipment thread.

 

[Sackett]

OK that sounds a lot like my problems, let me see if I got this right, because I am using a 1 1/2" tip on my 1 1/2" sucker tube, so possible fixes could be: #1-drill a hole in the nozzle BELOW the water line to increase WATER intake, thus increase water flow to WASH out pesky materials causing the flapper to hang open, or #2- decrease the size of intake nozzle, with the above mentioned "water holes" thus increasing the water flow "pressure" which in turn will "flush" out the pesky clogging materials...Hmmmm...I think that this MAY just work....I'm in NC right now, but be going home today and will sure try this out today or tomorrow!!!! I'll let you know if it works...and if what I wrote is not what you were saying let me know....Thanks again!! HarleyMan

 

[TheHarleyMan2]

If you are using 1 1/2 tube for the sucker tube and 1 1/2" nozzle it could be too big all together. All the sucker tubes out there are 2"-1 1/2" and the nozzles are 1", 3/4", and 1/2". The tube is usually bigger to pull a good vacuum to get the material, especially the gold flakes and fines in the sucker tube, because you need a good vacuum to pull it up with the material.

On my 2" hand suction dredge pump I am using 1 1/4 check vavles. They also have a collar on them to accomodate 1 1/2" pipe as well, but the check valve itself is 1 1/4.

I know on mine, both the sucker tube, (1 1/2") and hand suction dredge, (2"), I go from 1 1/2" to a 3/4 and 1/2" nozzle. Now on my hand suction dredge I have a 1" flex hose with my 3/4" nozzle.

Now just for note, I DO NOT have a hole drilled, (for water inlet), for my single Sucker Tube nozzles as I mentioned for my hand suction dredge pump nozzles.

If all you have is a single sucker tube, try reducing your nozzles down to 1" or 3/4" that way you are not piling too much material for your check valves to handle. I would try this option first. If it still seems to get clogged up, I would go ahead and drill a hole about 2-3" above the tip so it can draw in water while you suck the material up.

Hope this helps.

 

[Sackett]

yep I just bet that you solved my problems,,,just got home a few minutes ago, so it won't be until tomorrow until I can get it out to the creek,,,but thanks a lot I bet it'll work now when I reduce the nozzle down!!

 

[GrayCloud]

Well, there's the proof. Old Harley is smarter than he looks.

 

[TheHarleyMan2]

Well, there's the proof. Old Harley is smarter than he looks.

SSSHHHHHHHH! You were not supposed to tell anyone! Dang, now the cat is out of the bag!