My splitter build

[palmrose2]

Hose sizes and friction loss.

I'm not a hydraulics expert but do have some idea about friction loss as it pertains to water. I imagine that water would have less friction loss in a given size pipe @ a given flow rate. Friction loss is always measured as resistance in psi per foot of pipe, with various fittings given a value of pipe length. Of course in what I do a 10 psi loss can be a big deal.

I know from experience that you can get a huge amount of water through a small hole but that when you try to go much distance you can get into trouble in a hurry. I would think that @ 28gpm I would do whatever it takes to run 3/4 pressure lines and 1" or 1 1/4" suction. 3/4" is twice as large as 1/2". 1" is 4 times as large as 1/2". If nothing else you would running your engine under less load while in neutral and more engine power would available to work instead of heating the oil.

On your design, I can see that the pusher plate is a little on the small side. J.M.O.

My splitter is similar in design to yours. I had trouble with some wood wanting to slide off the push plate. My fix was to sharpen a chisel to a point and dance around the surface with my pneumatic chisel. Took five minutes and did a wonderful job.

A 4" cylinder 2' long holds about 1.3333333 gallons of fluid. 28 gpm would fill that space in 2.857 seconds. Knock off some fluid to account for the ram on the return stroke and you are looking at a potential 5 second cycle time. That's moving.

A 5"x24" cyl. holds about 2 gallons of fluid. Even that would be very fast.

 

[jags]

A 4" cylinder 2' long holds about 1.3333333 gallons of fluid. 28 gpm would fill that space in 2.857 seconds.

Keep in mind that the pump only creates 28 gpm on the low pressure side. When switching to the high pressure side it is much slower. Just sayin.

 

[Haywire Haywood]

High pressure side does 9.3 GPM

Ian

 

[jags]

High pressure side does 9.3 GPM

Ian

That will still be pretty darn respectable.

 

[palmrose2]

Keep in mind that the pump only creates 28 gpm on the low pressure side. When switching to the high pressure side it is much slower. Just sayin.

I'm running a 4"x24" cyl. with an 11 x 2.5 gpm pump and 8 hp techumse . I adjusted the pump so it stays @ 11 gpm for 80-95 percent of the time. I'm sure that haywires pump will most likely spend most of the time @ the greater flow rating.

I really need to get a pressure gage. Right now my regulator is screwed down tight. Really loads the engine but never stalls.

 

[jags]

I'm running a 4"x24" cyl. with an 11 x 2.5 gpm pump and 8 hp techumse .

I understand, but note that Haywires high pressure side is over 3 times the volume you are running at. You actually have an oversized motor for the size of the pump. He would need to run around 20+ HP to do the same thing as yours (meaning keep it in the low pressure/high volume side longer.) And even then, at 28 gpm on the high side, a 20 hp engine only has the ability to build about 1000 PSI before it will stall.

A really neat calculator:
http://www.surpluscenter.com/Hydraulic.htm

 

[ray benson]

The 2 stage 28gpm Barnes or Haldex pump - pumps about 7.25 gpm at the second stage.

 

[Haywire Haywood]

I stand corrected.. I got my calculation wrong somehow.. 7.25 GPM it is. I need a bigger gear in that thing.

Ian

 

[palmrose2]

I understand, but note that Haywires high pressure side is over 3 times the volume you are running at. You actually have an oversized motor for the size of the pump. He would need to run around 20+ HP to do the same thing as yours (meaning keep it in the low pressure/high volume side longer.) And even then, at 28 gpm on the high side, a 20 hp engine only has the ability to build about 1000 PSI before it will stall.

A really neat calculator:
http://www.surpluscenter.com/Hydraulic.htm

I'm going to raise my eyebrows now that I've visited the link. According to the calculator I can only run 400 psi with my 8 hp engine @ 11 gpm. That is doubling the hp requirements of gasoline over electric as recommended on the site. I REALLY want a gage now. I figured my engine was over sized but maybe not.

 

[Haywire Haywood]

I question that particular calculator as well, at least the "double figure for gas engine" part.

I've been using the formula HP=GPM x PSI / 1500 to figure out engine size. By that formula, I should be able to run up to 12 GPM at 2250PSI using an 18 hp engine.

Ian

 

[ericjeeper]

Man I landed a sweet deal today

Picked up a nice little wood splitter. Has the fixed wedge on wheels. Blown engine. Pump is there just needs a new briggs and it is good to go..
It is a real shame I did not find this one for Ian.. Would have saved him a whole bunch of fabricating.

 

[Haywire Haywood]

The figuring stuff out and the fabricating were half the fun and it would still be sitting there with no engine regardless... :hmm3grin2orange:

I towed it down to the local NAPA yesterday to get some hoses made and it tows well, even with the weight of the engine and fluid missing to help make the suspension work. Turned out to be as waste of time since they had to order fittings. They didn't have and couldn't order the 45 deg elbows I wanted so it will be straight fittings with a loop of hose. Won't be as neat as I envisioned.

The fellow wanted to put 1/2" hose on it and couldn't understand why I wanted 3/4. He said my pressure would drop with larger hose . He said "I've been doing this a long time...." At one point he said something to the effect, "I may be stupid but I know what I'm talking about." He also let me know that he didn't think that I had a clue what I was doing when he said, "You're paying for it, I'll make it." $11 per foot for 3/4" pressure line not including the fittings. This is going to get expensive.

I also just emailed Haldex to see if I could replace the gear in the high pressure section with a bigger one.

Ian

 

[ericjeeper]

Ian I would have told him a few things

First one being "Customer is always right" It don't make a rats arse what the customer wants.,.Providing they have the coin to cover their wants.
I am still in limbo whether to build up a high speed splitter.. Or just toss a 5horse on it and trade it off..
This one is going to take up even more shed space than the one I swapped you..

 

[kevin j]

your napa guy is bs.
what are the EL45 fittings you need to make the ideal routing you want?
hose ends or adaptors?

kcj

 

[jags]

I question that particular calculator as well, at least the "double figure for gas engine" part.

That part is true by the way. A true 5hp electric has the same or better continuous torque as a 10hp gasser. And when it is all said and done, its the torque that does the "work". Be it a log splitter or a pickup truck.

 

[Haywire Haywood]

I also just emailed Haldex to see if I could replace the gear in the high pressure section with a bigger one.

The answer to that is no, as I assumed it would be.

your napa guy is bs.
what are the EL45 fittings you need to make the ideal routing you want?
hose ends or adaptors?

kcj

I really don't know.. Ideally I wanted 45s at both cylinder and valve. Something to get the hose pointed off in the right direction, but not as restrictive as a hard 90 deg elbow. I assume that it would entail a 45 elbow that would screw into the ports and then swivel straight fittings for the hoses to screw onto. 90s would work if they were the large radius type. I think the Napa guy called them "British" fittings. He said they only came with flange type ends.

That part is true by the way. A true 5hp electric has the same or better continuous torque as a 10hp gasser. And when it is all said and done, its the torque that does the "work". Be it a log splitter or a pickup truck.

So that would mean that the 28gpm pump I have that Haldex says requires 16hp, would actually need a 32hp gas engine? If that is the case, they need to clarify their required HP ratings.

According to that calc, the high pressure side of my pump pushing 7gpm to 3000psi would require a 28+hp gas engine. The low side pushing 28gpm to the stock unload valve setting of 650psi would require a 25hp engine.

Northern Tools' 30 ton splitter has a 5.5hp engine and an 11 gallon pump. By that calculator, if you lowered the setting on that pump's unload valve to minimum, 400psi, it would require a 6 hp gas engine just to make the pump shift to the high pressure section. The high pressure section on that pump moves 3gpm. Assuming that the bypass on the control valve is the standard 2250psi, that calc says you would need 9.2 HP to run it up to where the valve would bypass.

I may be eating a lot of crow when I finally get an engine on my splitter, but I really doubt it. I'll have plenty of season salt and water on hand just in case though... :hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:

Ian

 

[Haywire Haywood]

The fellow wanted to put 1/2" hose on it and couldn't understand why I wanted 3/4. He said my pressure would drop with larger hose.

Gotta come back and give the guy some credit. I just got off the phone with the Tompkins guy. He said 1/2" hose and fittings are generally rated for 3000psi working pressure. 3/4" hose and fittings are generally rated for 2500 psi. The NAPA guy just didn't explain what he meant very well. Not a huge issue since the valves I've seen have the bypass set at 2250 out of the box.

I found some 1/2 to 3/4 straight steel adapters. I'm going to put those on the valve and cylinder and then have 3/4" swivel 90s crimped on the hose ends. That way if I eventually upgrade to a valve or cylinder with 3/4" ports, I can just take the adapters off and screw the hoses on. (yes, upgrade ideas are already forming)

Ian

 

[Haywire Haywood]

Finally found a donor engine...

 

[kevin j]

ian

cool, electric start. coming along. Should be a smooth running engine with less vibration.

I posted earlier about simple vibration mounts, at Grainger, that go through a 3/4 inch drilled hole, take a 3/8 motor plate mounting bolt, and are very easy to use. $4 each also. Don't have the p/n here.

Hose pressure rating: that sounds better, and correct. I take back all my bad thoughts about your NAPA guy……No worries though, SAE ratings are 4:1 for burst, so still about 10,000 minimum burst (subject to some reduction at tight bend radius). Not that he, or I , are recommending over pressuring, but you should be quite fine.

The EL45 adaptors, screwed into a port. You are correct, that is typically done. Generally, best to have the odd jump sizes or angles on an adaptor, and the hose with straight swivel ends of same size as hose. Then any replacement hoses use the most commonly stocked end fittings, and the odd stuff is the reusable part that stays on your component. And as you have planned, the odd adaptors with smaller ID go away if you find larger valves or other components.

What port threads do you have? I assumed NPT pipe threads, but ‘British’ usually means British tapered pipe (which is 1/2 thread per inch different than NPT, and also 55 degree thread angle instead of 60 degrees. They don’t interchange well.). There is BSPP parallel thread that uses a seal washer. ‘Flange’ usually means SAE split flange.

Here is a thread guide, see what looks familiar.

http://hydraulics.eaton.com/products/pdfs/fc/e-srov-ts009-e.pdf

Sounds like you have it mostly sorted. I would go from NPT, or whatever you have, with angles or elbows as needed, and get to JIC/SAE 37 degree flare (most common world wide) or ORFS oring face seal (harder to find for consumers, but all Cat, John Deere, etc are mostly face seals). ORFS is different than split flange. Split flange used 4 bolts and flanges. ORFS has a swivel nut with hex flats.

Don’t worry about some pressure drops through the elbows, sharp drilled 90 vs a bent stem 90. Bent stem is far better when looking at the fitting only, but in the overall system pressure drop, the restriction through the ID of the -8 adaptor itself will be more significant. Every little bit helps, but simply moving this much oil through the valve and fittings will be the lion’s share of the pressure drop. Go with what routes best and protects the hose and adaptor, so finding the replacement odd part does not become an issue when a log dropped on it !


Electric motor sizing. I often hear several forms:
‘It takes a 5 hp gas motor to replace a 2-1/2 hp electric motor.’
‘2 gasoline hp is equal to 1 electric hp’
‘1 electric hp is twice as strong as 1 gas hp’, and so on.

These statements are technically wrong. HP is simply speed times torque, with some unit corrections thrown in. Hp is hp, regardless of it source: steam engine, gas eng, electric motor, bicycle pedal cranks.

Yet in actual practice a 2-1/2 hp electric motor CAN replace a 5 hp gas engine. How can this be?
1. There may be a rated rpm difference (3600 or 1800 rpm) between the motors. An 1800 rpm 1 hp motor will have the same torque as an engine rated 2 hp at 3600 rpm, since hp is torque time speed. Twice speed, twice hp. But the pump would have half the flow at 1800 rpm as at 3600 rpm.

2. Most importantly, what matters is not only rated torque, but ‘torque rise’. That is the ability of the engine/motor to handle a momentary overload. If you plot full load torque vs rpm, a typical gas engine at 5 hp at 3600 rpm may have 10-20% torque rise before it lugs down to say 2500 rpm for its peak torque. If load increases further, the engine can stall (excluding flywheel and rotational momentum) because torque drops off again.

An electric motor can be loaded 200-250% of it rated load. Its torque generally keeps rising the more its rpm drops off below the synchronous speed (normally 1800 or 3600 rpm). It draws more amps, and pulls way more load for a while until it smokes. So a 2-1/2 hp electric motor can run its rated torque at say 3600 rpm all day for 2.5 hp. However, under momentary overload, it can rise to twice or more of the torque, and pull down to a lower rpm. It draws big amps, and would overheat if run continuously at this load, but on a splitter with intermittent load, it can very easily go a few seconds out of every minute pulling that load. In between with light load, the heat dissipates from the windings and armature.


Really simplified, but that is the basis for the ‘2 hp gas = 1 hp electric’ rule of thumb (or misunderstanding). Like most rules of thumb, it only applies to the most common situations. It is NOT valid for continuous loads, but could be for things with intermittent loads.


Torque rise is also why certain car or truck or chainsaw engines feel ‘torquey’. May not have more torque than another engine, but with more torque rise, they feel like they lug down and keep going, then pick up speed again.


we might be eating 'crow jerky' together, but I am confident your math and understanding are correct.


kcj

 

[dustytools]

Did you buy the mower or just the engine?