how do ground a lime silo in sand/bedrock ontop a hill

[1ajs]

got a 65foot lime silo thats got a static build up issues. has a ground plate cant get rods to go into ground they run into rocks and boulders. (some the size of a house) . first week we have tried using the silo screw feeder and its building up with lime in a way that suggests static charge build up

not sure what best coarse of action is to disapait.

lime is blown in from trucks into the silo.
silo has a ruber boot between it and the auger that feeds up to the slaker that then has platic pipe feeding the slury to pumps that feed to the reactor tanks that drain out 14in plastic pipe pipes going down the hill to a trench that goes to the settling ponds

 

[winnie]

I don't know enough about static charging in powders and such to make any recommendations.

But you can be pretty sure that improving the _grounding to Earth_ is a blind alley. You essentially have a large and unintentional electrostatic generator. Just like any other generator, grounding to Earth will remove voltage between the grounded point and the Earth, but will not get rid of voltages between the various parts of the generator.

I expect that you are going to be looking at careful bonding of various components of your system, use of added humidity, intentional air ionization to make the air a bit conductive, etc. But like I said I don't know enough about this part of things to make any real recommendations.

-Jon

 

[kwired]

I don't know enough about static charging in powders and such to make any recommendations.

But you can be pretty sure that improving the _grounding to Earth_ is a blind alley. You essentially have a large and unintentional electrostatic generator. Just like any other generator, grounding to Earth will remove voltage between the grounded point and the Earth, but will not get rid of voltages between the various parts of the generator.

I expect that you are going to be looking at careful bonding of various components of your system, use of added humidity, intentional air ionization to make the air a bit conductive, etc. But like I said I don't know enough about this part of things to make any real recommendations.

-Jon

I agree. I think he needs metallic or at least semi metallic components (plastics impregnated with conductive materials) where these charges are building up, which would prevent them from being built up in the first place.

 

[paulengr]

Limestone tends to be hygroscopic…it loves water and cakes up severely. So it may have more to do with moisture than anything.

In bad soil the answer is a auger ground. Dig a trench 20 feet long. Lay your ground rods in horizontally. Fill with concrete. The concrete tends to absorb and hold moisture.

As far as static charges go, you are literally rubbing loose electrons off the surfaces involved. Limestone isn’t very conductive in the first place so pneumatic transfer gets everything supercharged. ANY size wire and anything that serves as a reference (no solid Earth ground needed) controls the charge. Bond everything. The exception is people go crazy bonding metal silos sitting on concrete. The only reason to do it is to make a report for the insurance man. Don’t worry about wire size. Static grounds aren’t in the electrical codes because it’s a process thing. Also quite often pneumatic tubing will be polymer or rubber lined. Both are nonconductive. I’ve seen metal “deflectors” or a long section of piping or the last elbow made of metal just for bonding.

Last thing to consider: the truck MUST be bonded especially during loading and unloading. If they’re not chances are they’re driving off with your electrons! Need to neutralize charges wherever you can. Ask a vacuum truck guy how to do it. They’re experts because they deal with ground wires getting broken or things getting charged up all the time. Truck drivers don’t like to take 10 seconds to clip the bond wire to the truck. It “takes too much time”. Don’t unlock/open the port to let them unload until they do.

No electrical codes here because it’s a process problem. Also look at information about coal handling and gasoline (API). GCC can’t explode but it’s the same problem and there is detailed static control information there. Polymer pellets for plastic parts plants too. Sounds to me like either improper procedures during unloading or improper design or install with the pneumatics. You shouldn’t be having a problem.

 

[kwired]

Limestone tends to be hygroscopic…it loves water and cakes up severely. So it may have more to do with moisture than anything.

In bad soil the answer is a auger ground. Dig a trench 20 feet long. Lay your ground rods in horizontally. Fill with concrete. The concrete tends to absorb and hold moisture.

As far as static charges go, you are literally rubbing loose electrons off the surfaces involved. Limestone isn’t very conductive in the first place so pneumatic transfer gets everything supercharged. ANY size wire and anything that serves as a reference (no solid Earth ground needed) controls the charge. Bond everything. The exception is people go crazy bonding metal silos sitting on concrete. The only reason to do it is to make a report for the insurance man. Don’t worry about wire size. Static grounds aren’t in the electrical codes because it’s a process thing. Also quite often pneumatic tubing will be polymer or rubber lined. Both are nonconductive. I’ve seen metal “deflectors” or a long section of piping or the last elbow made of metal just for bonding.

Last thing to consider: the truck MUST be bonded especially during loading and unloading. If they’re not chances are they’re driving off with your electrons! Need to neutralize charges wherever you can. Ask a vacuum truck guy how to do it. They’re experts because they deal with ground wires getting broken or things getting charged up all the time. Truck drivers don’t like to take 10 seconds to clip the bond wire to the truck. It “takes too much time”. Don’t unlock/open the port to let them unload until they do.

No electrical codes here because it’s a process problem. Also look at information about coal handling and gasoline (API). GCC can’t explode but it’s the same problem and there is detailed static control information there. Polymer pellets for plastic parts plants too. Sounds to me like either improper procedures during unloading or improper design or install with the pneumatics. You shouldn’t be having a problem.

But don't neutralize until it weigh's out- if selling by weight you sell those electrons that might not be there at the destination

 

[paulengr]

But don't neutralize until it weigh's out- if selling by weight you sell those electrons that might not be there at the destination

That would be like coal trucks hosing down their loads before crossing the scales?

Seriously google a Kelvin generator. You can make static charges with water.

 

[kwired]

That would be like coal trucks hosing down their loads before crossing the scales?

Seriously google a Kelvin generator. You can make static charges with water.

Was just for funniness. How many electrons needed to be significant enough weight?

Don't know enough about coal, do they check moisture content like they do grain?

Heard of a farmer that used to fill his cap with corn and hold it out the window on the way to elevator. Always wanted to submit that as his test sample instead of them drawing a sample. It of course would be drier than the bulk of the load from that trip. Now a days they have automatic probe that pulls sample from deeper inside the trailer and not just take some off the top where it very well could be drier.

 

[petersonra]

I agree with Paul this is a terrible design. It just guarantees you're going to get static electricity generated when the powder goes through the plastic pipe.

I don't know if there's any simple solution to this problem. If the plastic pipe has flanges you could try putting a SS grounding ring between the flanges and just tie them to the structure. Grounding as in pounding rods into the earth is not going to help much if it all.

You could also try drilling some holes through the plastic pipe and threading stainless steel bolts through it that you could use to Bond to the structure. Problem is this kind of thing could also lead to the powder building up where the bolts are at.

You might also be able to replace sections of the plastic pipe with stainless steel pipe and bond them to the structure.

You may have to get someone who actually knows what he's doing to design something that will actually work, especially if the cheap solutions are tried and don't work.

 

[1ajs]

its rubber flex lines from the truck to the silo pipe at the bottom standard hook up
no plastic pipe on the silo all steel