Need a Low Electrical Resistance Oil

what about a spring loaded carbon brush connected to top of ram with carbon bit pressing on piston

so it makes connection like a motor

Cannot introduce any kind of heat or clamp to ram . Heat will weaken it and a clamp would only be knocked off because the ram dissapears completely when lowered .

Ive searched and found nothing

i had this problem on a fork lift truck the main mast is not connected electricly to the rest of the body of the truck and static electricity was building up.

we had to fit home made carbon brushes this solved the problem.

But we found nothing commercialy avalable.

perhaps some else on this site can help.

But youve beat me sorry

If I'm visualising this correctly, you want the fluid in the hoses to carry the bond. Why not use a braided hose to do the same job?

As we can see by the drawing, the "ram" is electrically isolated from the barrel of the cylinder. Are you wanting to bond the ram using mildly conductive fluid?

I could be all wet, too.

Hi Lyn yes i think thats wht he after.

as i sadi we had the same problem on fork lift trucks, Infact all hydrulics have the same problem.

and yes you can fit conductive hoses but that doesnt connect to the ram.

Which if you look at the ram picture supplied by lyn is electricaly isolated at the top where the ram goes through a rubber seal and the piston uses "O" rings so that is isolated as well

Yes . Is there anything resembling hydraulic oil or an ATF available ?

No.

i havent found anything like what you need, and there wasnt anything when i looked 2 years ago

you can get anti-static spray and then if you spray the seal where th piston comes out of the ram, the static will disapate there the spray wont damage the seals or the piston

http://www.gaec.biz/anti_static.htm

http://www.rapidonline.com/productinfo.aspx?mode=p&tier1=Tools%2C+Fasteners+%26+Production+Equipment&tier2=Service+Aids&tier3=Cleansers+%26+Solvents&tier4=Anti-static+spray&moduleno=34282

http://www.westmontinc.com/

http://www.stencilrolls.com/paints.htm

There is an anti-static "dope" that I have used extensively called Statsafe 3000.

It increases the conductivity of the oil, but I do not know whether by enough for your purpose. Statsafe itself has a conductivity of 420 to 540 pS/m.

www.innospecinc.com

In underground mining the roof support chocks use water treated with 0.5% Talina C (from Shell) or similar products from other suppliers as the hydraulic medium. Biodegradable and non toxic additives are available. The mixture works fine at 5000psi. The cylinder rods are often brass (or bronze that looks like brass) sleeved.

Another solution is to use bronze bearing bushes for the rods much like in suspension struts on dump trucks.

I have done enough welding on farm equipment to know that hydraulic cylinders are not perfectly electrically isolated internally or at least are very poorly isolated at best.

There are a number of metal to metal contact points between the rod and head sleeve and the inner piston plate and cylinder walls at all times due to slight side pressures from the rod and piston deflecting under load.

if the seals are good there should be no metal to metal contact other wise you get scoring on the tubes/ram/

i know that in older rams the piston seals are metal like piston rings and these you would get electrical connection, But a lot of newer cylinders dont use the metal rings,Only use rubber

I don't know of conductive oils, but what about conductive seals for the ram? Just like the rings in an engine, or even conductive rubber.

The rubber could be carbon impregnated (and probaably already is) with "carbon black" and thus would dissipate the static charge. You are only talking relatively small charge in terms of static.

I suspect that the cylinder manufacturers could accomodate this with a specialist seal kit. I know that we got seals for cylinders working in temps where max was -20C and others where min was +80C. Conductive rubber is nothing new.

Have to say guys that ye are a great help ! Thanks for the Pics and great advice . Next thing now is where will i find all these conductive O-Rings ? The picture is a perfect example but my trim ram sits alone in the water waiting for the powerhead to be trimmed down before any earth bond is made . I think it is at this point of contact that the static is discharged and therefore the pitting takes place .

Now wait a minute! If it is sitting in water, then it is grounded by the water. I believe you are seeing electrolysis, not static electricity. Whole different problem!

Look into sacrificial electrodes.

That makes much more sense to me. GA

Do you mean sacrificial anodes ? These are fitted already but because these are fitted to the bonded surfaces they are not protecting the rams . This is why i want to bring the rams into the Bonded circuit

I don't know a lot about sacrificial electrodes - whether they are always anodes or not, or where they are mounted, how many etc....

I do know the problem is NOT static electricity.

Without knowing any details, it sounds to me like a poor design if hydraulic ram shafts are left in the water when not being used. Some photos might help.

If you were to attach magnesium to the cylinders you will probably see the pitting stop. You can use any shape of magnesium you can find.

Refueling on airports is always accompanied by bonding-grounding wires. Can you just attach a grounding wire between the pivot points of the ram?

Can you connect a coiled bonding wire between the rod end and the cylinder head?

If there is no filter in the system, you could try adding a whole bunch of powdered graphite to the oil, but if there is a filter (there usually is) you'll just be clogging your filter. Also if there is any micro-hydraulics in the system, the graphite will clog it up.

Now on offshore oil rigs, instead of using oil, they use what is essentially 50/50 water/ethylene and/or propylene glycol, essentially water/antifreeze, for hydraulic control systems because the water/glycol mix is relatively non-toxic to marine life. This is the solution I would suggest for you. Be aware that under certain circumstances some seal materials will be attacked by the water/glycol, but Nitrile/Buna-N is perfectly acceptable in most cases.

Thats the answer, a flexible, braided conductor, connected to the clevis of the Ram.

If i am reading the question properly , this person is saying that he has a hydralic cylinders that is emersed in water all of the time. And that the piston rod dose not have a thread or clevis on the end of it, so it is not being used to push or pull anything.

From this i assume that the piston rod is for location only, which makes it a plunger.

The cylinder is probably a single acting one, that is mounted by a flange at the nose or a thread on the nose so when the cylider is in the retracted position there is no piston rod protuding, and while in this position the rod is in an oiled environment inside the cylinder.

But I think that the cylinder spends more time in the extended position being attact by the sea water, the object that is being held in place will probable have nylon bushes for the piston rods to go through, and to stop the rods from being bent when in this state the ends of the piston rods will engage in to a second set of bushes.

If this is the case then the piston rods will be totaly isolated in all of its positions. so some kind of earthing atachment will need to be fitted to the piston rodin its extended mode. A stainless steel ring for the rod to go through with the braided link attached to it. Or even replacing the nylon bushesthat stopp the rods from being bent might help.