My buddies and I are building a log splitter and I have a few questions regarding suction hoses, line sizes and reducers, etc.

1) What hose material needs to be used for the suction line? It is 1". What type of clamps are required so there is no danger of leaking or being blown off by pressure?

2) The pump is a 22 GPM, with a 1/2" outlet. It must connect to a 3/4" inlet on the control. Do I use 1/2" hose or 3/4" hose with appropriate reducers?

3) The control working ports are 1/2". The cylinder ports are 3/4". The cylinder is a Prince 3000PSI max. 5", 30" stroke with a 2" ram. My question is hose size again, 1/2" or 3/4" with reducers on the right end?

4) Is there a general design guidline that says you should use all the same size hoses, even when the various ports vary on the devices?

5) How do you bleed the system on startup?

Any other general advise would be great! We're all very excited to fire this up and have a great experience. We took the general design from a 32 Ton splitter in a catalog and bought the same parts as it listed.

Thanks

1."suction" line max pressure will be from outside, the atmospere pressure max 1bar or about 15 psi. You need a special kind of hose, armed to protect from collapsing. Ask your hydraulic shop...you will need at least a 1 1/2 inch to stay below max recommended 4 ft/s velocity...2 inch preferrable..regular clamps enough...just to make sure air cant be "sucked" in se SAE 100R4 Suction & Return Hose at Suction and return hose

2.use 3/4 inch, will put you on about 20 ft/s, not great but ok. Decide your system pressure before buying this hose, if higher than 2250 psi you need more than std R2 hose

3. same as outlet hose at pt #2.

4. no but it dont make sense when you are going to use full pump flow on all lines

5. No need to bleed, all air will be pushed out through the seals and fittings, just do it slowly, fast running air can create over heat at seals

I would put in a regenerative inline valve, between directional valve and cylinder. That will "boost" the speed on splitting when there is "light duty", a 2' pistonrod and 22 gpm pump flow, will make it a rocket. This valve is pressure sensed with adjustable pressure, when you want high force slow cycle to kick in.

see my regenerativ "boost" valve available in different set ups, depending on max flow and max pressure.
I dont know the stroke lenght but if it is 24" your force will be just short 10 tons/ 1000 psi pressure
outgoing cycle time 5.6 sec ingoing cycle time 4.7 sec. and outgoing with the boost valve 0.9 sec cycle with 1.6 ton force.
Thats very fast, if you want boost slower and stronger, u'll need a thicker piston rod. A 3" rod will give you 2.0 sec cycle with a 3.6 ton force

Thanks very much for your reply.

I need to make a correction and ask another question. I appreciate your patience, as you can tell, I know nothing about hydraulics.

The pump is actually a 16 gpm, not a 22 gpm. The inlet side has a 1" hose connection, and the outlet is a 1/2" fitting. Now my question:

Does it provide any benefit to use a larger hose than the device connections? You recommend a 1 1/2" suction line, but it goes into a 1" port on the pump. Same question on the pump outlet line to the control. Since it's 1/2", how does it help to go to a 3/4" hose?

Believe me, I'm not doubting you, just trying to understand. Thanks.

The pump is supplied oil by the atmospheric pressure in the reservoir. Atmospheric pressure is about 1bar or 15 psi. By rotating the pump creates a vacuum on inlet side, 0 bar. If that vacuum space don’t get fully filled with oil (from atm pressure) there will be vacuum bubbles left on the outlet (pressure ) side. These bubbles will collapse from the pressure and that will cavitate the material in the pump, cavitation, which can ruin the pump in short time. We want as much as possible of these 15 psi be available as close as possible to the pump. By adding more restriction 1” inlet hose between tank and pump, we will lose some of that 15 psi atmospheric pressure. It’s a good idea to put a vacuum gauge on the inlet side of the pump. That can help indicate when suction filter is clogged, and that way save your pump from damage
This will work the same on the outlet side of the system. Pressure losses here will create a lot of heat, with over heating as result.
Your inlet is 1" and is the major restriction in that inlet line. We can’t change it without changing pump. There will be a pressure loss , over that inlet port. How big depends on actual flow, gpm. Let's say that inlet port is 1" long. Adding a 1" inlet hose that is another 24"+ inches long will make that (little simplified) pressure loss, 24 times larger. Even more if you have a bend on that hose.
This is like the electric system, all resistances inline with each other will add up. I'm sure you know what happens if you don’t use enough gauge wire for the amperage that's going thru. There will be losses in voltage, and you bulb will do less watts than the rating.
You can’t do anything about you ports on pumps valves and motors, but you can work on the rest by "oversize" a little
Look at this Nomographic chart, that will help you choose appropriate lines for inlet, pressure and return.
Hope this explained a little better WHY oversize!?


“Aw come on”

“Swedish Forest engineer with a 25+ years experience in Scandinavian logging equipment , teaching operating and hydraulic , pneumatic, electric mechanical machine systems”

May I add:

1)Cavitation Tendency = p static pressure - p vapour pressure / Y x r x v2 where Y is Fluid Factor , v is fluid speed and r is specific weight. Normally it is not a practical formula.
2)Any change in pressure will cause instability of Air in Oil solubility.
3)Air bubbles in Oil under pressure of over 600 psi can cause detonation and
..it called Diesel Effect. The small explotions will cause erosion of pump ,
..valves and other components eccompanied by noise .