Gravity-purification in your hydraulic tank (or perhaps better,... on the shelf)

[Sodo]

Why wouldn't you stick a whole bunch of neodymium magnets on the bottom of the hydraulic oil tank next time the lid's off?

All the steel goes down by gravity when it's still.
If eqpt gets parked for a month I'll bet the steel drops to the bottom 100%.
Now if there's a way to get it to stay there, and not circulate, it's better for the machine.

Magnets will probably hold the steel at the bottom.
A plastic mesh like a pot-scrubbie above the magnets would create a "still area" in the vicinity of the magnets.
The mesh could be cut in the shape of the hydraulic tank where it steadies itself against the tank walls and prevents sloshing below it.

It seems like a real simple method to reduce the steel circulating in the oil.
Stone might settle to the bottom too, but the magnets wouldn't hold stone.
But if the stone settled down into the mesh, it might remain there, and not circulate as much.

 

[Portuguese Farmer]

Why wouldn't you stick a whole bunch of neodymium magnets on the bottom of the hydraulic oil tank next time the lid's off?

All the steel goes down by gravity when it's still.
If eqpt gets parked for a month I'll bet the steel drops to the bottom 100%.
Now if there's a way to get it to stay there, and not circulate, it's better for the machine.

Magnets will probably hold the steel at the bottom.
A plastic mesh like a pot-scrubbie above the magnets would create a "still area" in the vicinity of the magnets.
The mesh could be cut in the shape of the hydraulic tank where it steadies itself against the tank walls and prevents sloshing below it.

It seems like a real simple method to reduce the steel circulating in the oil.
Stone might settle to the bottom too, but the magnets wouldn't hold stone.
But if the stone settled down into the mesh, it might remain there, and not circulate as much.

Magnetic drain plug

 

[thclimer]

I'm only guessing if there is that much "steel" in your hydraulic system you have bigger problems that need to be addressed or will be evident by operational problems. If there is a small amount I would think the filter would catch it preventing it from getting to critical parts like your pump.

 

[oldnslo]

Companies make magnet trees for use in reservoirs mostly designed for industrial use pumps and motors that have case drains that typically cannot be run through a return line filter. Like thclimbrr states a good return line filter is a better defense in keeping the reservoir clean on most systems especially mobile equipment since there reservoir volume is usually very low compared to pump volume.

 

[bdhsfz6]

Not a bad idea but many of those particles are stainless steel & brass which a magnet won't pick up.

 

[Sodo]

The thing is..... hydraulic filtration goes down to 10 microns "at best".
Oil film thickness can be 1/2 micron when a pump is "working hard".

So particles between ----> ~2 and 10 microns are flowing freely, getting mashed between your precision surfaces.
So there's a lot of steel dust that you cannot filter out, you just live with it.
There is a "normal component lifetime" associated with "normal levels of lubricant contamination".

If you can reduce contamination, longer component lifetime can be expected.
One way is to replace the hydraulic oil at shorter intervals.

=============================
It's cool when magnets catch and hold larger particles.

But on on very tiny particles, magnetic attraction is very weak. Like the fine dust on a magnet, it's just "barely held" by a magnet.
The magnets don't draw fine steel dust out of the oil. But they can "hold it" if it drops down onto the magnet by gravity (when the oil is "still").

That's why you'd want lots of magnets spread around rather than just one drainplug.

You want to catch and hold any very-hard steel wear-particles for sure.
Brass & aluminum can be considered a "cushion" - they are the best kind of dust to have.

Stone is bad though. Water is bad.

The concept of catching & holding oil contaminants "out of the flow" in a non-moving area on the bottom of the reservoir seems reasonable to get longer life from valve bodies and pumps.

Then the bulk of the hours, the machine is operating with the upper stratification (the more purified) oil.

The gravity method seems "real easy" too (good for the lazy person !!)

 

[Sodo]

Here's another way.
I think I like this way better.
It's straightforward and you can see the benefit.

If you put eqpt away for a few months in the winter, run the machine, get it warmed up, then drain the Hydr. oil reservoir.

In the spring all the metal and stone will be at the bottom of your pail.
You will see the layer. Pour the clear oil back in, being careful to stop, leaving the sediment behind. You're not purifying all of the oil, just the portion that's in the reservoir.

If you take the lid off and look at the oil, you'll know when it becomes clean again. It gets significantly clean in a month, and clear as honey in 2 months. It's useful to set the pail purifying at an angle so you can get more clear oil out without disturbing the sediment.

 

[rScotty]

Why wouldn't you stick a whole bunch of neodymium magnets on the bottom of the hydraulic oil tank next time the lid's off?

All the steel goes down by gravity when it's still.
If eqpt gets parked for a month I'll bet the steel drops to the bottom 100%.
Now if there's a way to get it to stay there, and not circulate, it's better for the machine.

Magnets will probably hold the steel at the bottom.
A plastic mesh like a pot-scrubbie above the magnets would create a "still area" in the vicinity of the magnets.
The mesh could be cut in the shape of the hydraulic tank where it steadies itself against the tank walls and prevents sloshing below it.

It seems like a real simple method to reduce the steel circulating in the oil.
Stone might settle to the bottom too, but the magnets wouldn't hold stone.
But if the stone settled down into the mesh, it might remain there, and not circulate as much.

You are right that filtration by settling is the very best type of filtration. It is widely used for removing things from solution that are too small for filters with pores to handle. Great for separating fine particles held in solution for everything from dyes to pharmaceuticals. Handy for analytics, too, since settlement mateiral naturally stratifies as it settles.
Centrifuging anything is the same as natural settlement, just faster.

The brewing industry uses natural settlement in vats and the siphoning to remove yeast from beer before bottling.

Downside to magnets used as you describe is that trapped ferromagnetic particles line up to follow the magnetic field which "short circuits" the magnetic field and makes its effect less far reaching. An old trick to get around that and also get rid of ferromagnetic particles is to put your neo magnets onto the outside of the disposable filter cannister. - which is made of thin steel. Win/win.

Another way to use pore filtration is to direct part of the flow through a by-pass fllter with a very small pore size. Hi performance pumps and engines often direct a few percent of the flow through a sub-micron filter. Over time, that really makes a difference.
Bypass filters have been around for 100 years. Was popular with planes in WWII. And with cars in the 1950s. There is no downside to them. You can buy a complete bypass filtration kit on Amazon for very reasonable.

Which reminds me that Kubotas with the "HSTplus" transmission have an additional replaceable bypass filter for superfiltration. That system not only super filters the HST oil 100%, over time it does the same for all the trans/hydraulic oil. That filter is specially built and about $75 to replace - maybe the high price is because sub 2 micron media is special, and also the filter body is a pressure type rather than a suction fllter.
Just me rambling,
rScotty

 

[ZiggyD]

Here's another way.
I think I like this way better.
It's straightforward and you can see the benefit.

If you put eqpt away for a few months in the winter, run the machine, get it warmed up, then drain the Hydr. oil reservoir.

In the spring all the metal and stone will be at the bottom of your pail.
You will see the layer. Pour the clear oil back in, being careful to stop, leaving the sediment behind. You're not purifying all of the oil, just the portion that's in the reservoir.

If you take the lid off and look at the oil, you'll know when it becomes clean again. It gets significantly clean in a month, and clear as honey in 2 months. It's useful to set the pail purifying at an angle so you can get more clear oil out without disturbing the sediment.

My dealer recommended doing something similar instead of replacing all the hydraulic fluid. Essentially replace the filter at the appropriate intervals, drain a quart or two and refill accordingly. They said the it didn’t make sense to replace all 12 gallons of fluid and to save my money

 

[rScotty]

Here's another way.
I think I like this way better.
It's straightforward and you can see the benefit.

If you put eqpt away for a few months in the winter, run the machine, get it warmed up, then drain the Hydr. oil reservoir.

In the spring all the metal and stone will be at the bottom of your pail.
You will see the layer. Pour the clear oil back in, being careful to stop, leaving the sediment behind. You're not purifying all of the oil, just the portion that's in the reservoir.

If you take the lid off and look at the oil, you'll know when it becomes clean again. It gets significantly clean in a month, and clear as honey in 2 months. It's useful to set the pail purifying at an angle so you can get more clear oil out without disturbing the sediment.

Gravity purification was once a common industrial process. Much cheaper than a centrifuge for large samples. I remember one text book even had typical equations for time vs materials and liquids - now long forgotten.
The process was ancient & sometimes used to purify a liquid, but usually for collecting and concentrating precipitates.
The standard way to remove the liquid is to use a siphon rather than pour. Much better results.