Hydraulic Filter Question

[unixkid]

I'm building a log splitter and am to the point of putting the hydraulic system together. My question is about the return line filter. All I see available from Surplus Center for return line filters are typical canister filters of varying sizes but they all pretty much say max 200 psi operation. How is it possible to put a 200 psi filter on a system that has all other components rated for 3000 psi ???? My novice approach is to put every component rated for the same max psi.

Please help.

The splitter will be : 25 gallon tank, 16 gpm pump, auto-cycle valve, 3/4 in lines, splitting cylinder, log lift valve, 3/8 in lines, log lift cylinder, return filter.

Thanks,
-unixkid

 

[murphy1244]

I'm building a log splitter and am to the point of putting the hydraulic system together. My question is about the return line filter. All I see available from Surplus Center for return line filters are typical canister filters of varying sizes but they all pretty much say max 200 psi operation. How is it possible to put a 200 psi filter on a system that has all other components rated for 3000 psi ???? My novice approach is to put every component rated for the same max psi.

Please help.

The splitter will be : 25 gallon tank, 16 gpm pump, auto-cycle valve, 3/4 in lines, splitting cylinder, log lift valve, 3/8 in lines, log lift cylinder, return filter.

Thanks,
-unixkid

Cause there is very little restriction on the return = low psi

 

[J_J]

The return or OUT port on the log splitter valve has very little restriction to the fluid so it just flows almost with no pressure. The hyd filter should go in the return flow path.

You could even put your hand in the return flow and not be hurt, except by heated fluid.

They do make inline high pressure filters capable of handling 3000 psi, but you do not need them in a log splitter hyd circuit.

 

[benitez]

i have a 30 ton north star log splitter and it has no filter. should i put 1 on ?

 

[J_J]

Yes sir, every hyd system should have a filter .

I am surprised that the manufacturer did not install a filter.

Did you buy it new?

I should ask does it have an engine driven pump, as a 3pt log splitter fluid would get filtered by the tractor hyd filter.

 

[benitez]

im sorry its not a 3pt log splitter and yes i bought it new last year from north star

 

[unixkid]

Thank you for the replies. I understand now.

-unixkid

 

[ilander]

If I may put my two cents worth in, hydraulic filters need not be on the return line. They can be on the suction line before the pump. I have three tractors with such filters, a JD440, CaseIH DX25E and my JD510 has a close mesh screen type filter before the first pump with other paper filters scattered about the circuit.

There's nothing wrong with putting a filter on the return side, just make certain the filter has a built in relief valve, many filters do. There's a cold weather issue (temps colder than 10 degrees F) with filters on a line with potential to build pressure, such as the return line. My example is on the DX25e. It has a second filter between the main pump and the HST unit. In extreme cold weather the manufacturer's recommended filter leaks out all the oil past the filter gasket no matter how tight the filter is. I cured this problem by going to a filter expert at NAPA, who got me a filter that has twice the micron rating that is used only during extreme cold weather months (Dec - Feb). In March I switch back to what is recommended by Case.

I would also like to say that during extreme cold weather, the filter on the suction side of the main pump causes no priming or supply issues. Based on my experience, I prefer filters on the suction side.

 

[J_J]

What you say is true, but the the return filter is recommend by most people.

I have never seen one on the suction side of a log splitter.

Most tractor hydrostatic systems have suctions filters.

Moisture in any filter in a cold climate will cause problems, be it suction or return.

 

[IceStationZebra]

I would also like to say that during extreme cold weather, the filter on the suction side of the main pump causes no priming or supply issues. Based on my experience, I prefer filters on the suction side.

The average mesh filter is only good for about 150-200 micron, whereas generic paper filters are about 40 micron. The mesh "filter" is really used as a trash guard, it isn't fine enough to stop abrasive wear. That is why many systems use a wire mesh filter pre-pump and a paper filter on the return line.

Theoretically before the pump is usually the best place for a filter on offroad machinery as it protects the pump, which is usually one of the most expensive components. But it's usually too difficult to overcome the restriction with cold oil, thus you rarely see it. And just because you don't have "priming" issues doesn't mean that you aren't causing more wear to the pump. It is a tradeoff engineers make to reduce warranty costs. They can not risk manufacturing or the end user letting something get into the system.

Filters are a discussion that could go on for hours. Every application will be a little different. You have to take into account what needs to be protected, what can you spend, space available, maintenance expectations, type of oil, flow constant or varies, filter stable or vibrating, etc.

With regard to your filter issue on the DX25e, did you switch to a winter grade oil? If the oil is so thick that your filter is leaking you should be running thinner oil. Otherwise you could be causing hidden damage to other components that rely on sleeve bearings, small channels and orifices.

ISZ