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Suction Strainer

Suction Strainer

Suction Strainer

I have been building a log splitter and i have a 13.6 gpm pump.  To start the system i have a suction strainer 149 micron that says it is not for pumps over 10 gpm.  am i ok to use this on the 13.6 gpm pump despite the rating, or will it effect my flow, and pump performance.

I know they make a strainer that looks like a filter cartridge for 50 bucks that can handle 15 gpm.  but i dont want to buy it if i dont have too, ya know.

ANy help....

RE: Suction Strainer

50 bucks is a mere pittance if it avoids entering into a urinating contest with the pump vendor - or the strainer vendor, for that matter - over warranty concerns.

That said, your 10 gpm strainer would probably still work for 14 gpm.  There just wouldn't be any guarantees.



RE: Suction Strainer

The flow rating is heavily influenced on the oil viscosity. Considering you have this on a log splitter I will assume you are going to start it with cold oil, in which case the oil will be thick. The issue here is that you will create a vacuum to the pump inlet, which can/will kill the pump. Gear pumps can handle some vacuum during start-up for short 30-60 second periods. It will shorten their life but they won't self-destruct. Piston pumps DO NOT like vacuum and can get seriously damaged in a hurry.

The other concern would be physical. Depending on the design you may collapse the strainer or suction line under high suction. This would almost completely block the pump inlet causing almost certain damage and/or destruction of the pump.

There are some things you can do to help yourself if you are intent on using this strainer.
1. Leave the machine in a warm space to heat up the oil before you start it.
2. Use thinner oil. I wouldn't go below an ISO32 unless you are in arctic conditions.
3. Start the engine and let the oil come up to temperature before you run the engine above idle.
4. You could install a vacuum gauge in the pump inlet line. You don't want to see any vacuum, but with cold oil you can live with 45-60 seconds at start-up.

The other option is to not install a strainer at all, or take it off once you have gotten everything running and all the oil have been filtered a couple of times. All the strainer really does is prevent large chunks in the reservoir from getting into the pump. The particles that do the majority of the wear to the system over time go right through the strainer. To put it into perspective your strainer is 149 micron, but most off-road systems use a full flow filter rated at 30-40 micron and many are now down to 10 micron.

If you have a good breather and you know that someone isn't going to dump junk into the reservoir it isn't really doing you any good. I like to put a magnet in the reservoir as cheap insurance to catch any ferrous objects or particles that may get into the oil.


RE: Suction Strainer

Yeah i have a 10 micron filter on the return,  i appreciate ur advice, i may just let it run for a few times with the strainer and then take it out of the system.  I just am worried about leaving it open to the pump and the cylinder i mean if something goes in it could hurt the pump and the cylinder, but at the same time i dont want to hinder performance.  What do u think about the filter cartridge for the suction is good up to 15 gal.  Is this worth the investment.

RE: Suction Strainer

Get rid of the suction filter/strainer.  Put a filler basket in the tank filler tube to keep the big stuff from falling into the tank in the first place.  The little stuff, it should be really little stuff, will pass through the pump once and be caught by the return filter.
The return filter rated flow should be 2 to 3 times the system flow rate so you have low return pressure during cold startup.  By the time the system is warm, you will have circulated the oil in the tank several times through the return filter.


RE: Suction Strainer

yes i agree my return filter is rated at 20 gpm.  I would take the strainer out but i know there is a few little shavings in the reservoir from putting it together.  I need something there initially.

RE: Suction Strainer

I'm more concerned about your pump size and engine Hp. rating.    That's a woeful area with most "homemade" logsplitters.   Biggest mistake people make is using a pump that is too large for the engine they have available.

Unless the 13.6 GPM pump is a 2-stage pump that kicks down to a much lower flow when pressure raises, the 13.6 GPM at a respectable pressure like 2000 PSI would require at least 15-16 Hp.   You'd rather have the cylinder move a bit slower (by selecting a smaller pump) than have the engine die everytime you need to push through a tough split.

RE: Suction Strainer

I designed the system of this log splitter and have done all the necessary calculations.  For a two stage pump which i have at 13.6 gpm the first stage is @ 650 psi which requires a hp of about 6.  You can check it if u want but i know it is right.  For an 11 gpm pump you need 5 hp.  Im not concerned with this part of the system.  The topic is about the suction strainer.

RE: Suction Strainer

If you know that you have particles in your reservoir you should remove them before even starting your build. In production manufacturers often use pickling fluid. I'm not sure what it is made of, but a good substitute is diesel fuel. This cuts any cutting fluid/grease/oil that can hold onto particles while at the same time keeping some anti-rust properties.

1. Insert magnet into reservoir
2. plug all the holes but one
3. add diesel fuel, slosh around vigorously
4. drain diesel
5. inspect, repeat if necessary
6. remove magnet, clean off particles, reinstall in reservoir near pump inlet

Another thing you could do initially is plumb the pump right into the filter and then to tank. This way any you can't contaminate the valve or cylinder.

I do like Hydtool's suggestion of a screen in the fill cap. This is cheap insurance. You wouldn't believe the amount of crap that can be in "new" oil. I once commissioned a new 200hp power unit using seven 55gal drums of premium Mobil oil. As I emptied each drum I looked at the bottom and was surprised by the amount and size of particles left behind. That is why we filled each machine using a filter cart, which is simply a cheap gear pump that sucks the oil out of the drums and passes it through some filters before dumping it in the reservoir.


RE: Suction Strainer

I do like the idea of a magnet on the tank.  Thanks guys for all of the good info.

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