Thanks.... side load not recommended. I had the same idea he had.
Ian
Ian
HP requirement for 22gpm Pump?
- Thread starter Haywire Haywood
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Side load not a good plan.
Here is what I would do. (Actually, it is what I am doing…)
-grab the 16 hp twin cylinder engine while you can.
-Watch for cheap bell housing and coupling as those will be the same either way
-Run the numbers for your cylinder to see if 22 vs 28 gpm is acceptable to you
-Watch for a 30 to 40 gpm valve with detent on return. Single spool, open centered spool, with inlet relief valves, are fairly easily available at surplus center, ebay, scrap yards, or northern, but finding one with a detent is a bit harder. If you find one, let me know, I am looking for this size also for my 28 pump.
-When time comes, build all the mechanical and welding portions of the project first. If you still have not located a large valve, then buy the 22 pump instead of the 28, and the standard Prince valve.
-Alternate, buy the 28 gpm pump and smaller valve, but run at slower engine speed. That hurts the slow speed, but the fast speed is the same and the engine runs slower and quieter.
kcj
pasted in below.
VALVE RATINGS
Valve 'ratings' are a lot like 'tonnage ratings' : determined more by marketing than by an objective standard.
In case of a valve, or any flow component, it is simply an orifice at wide open. So the flow is a function of how much pressure drop you are willing to tolerate (assuming the device does not malfunction).
For example, the common Prince splitter valve is 'rated' at 25 gpm maximum. What if I put 30 into it?
First, this rating of 25 is assumed to be 25 gpm in from the pump, but remember that 25 gpm into the rod side on retract is 30 to 35 gpm out the closed side. I will return to that.
Second, it does not mean that 25 gpm passes and the other 5 gpm disappears. Since this is a positive, fixed displacement gear pump, if it moves 30 gpm, the oil has to go somewhere. So it goes through the valve. It just creates more pressure drop and load on the pump. Remember, pressure is a result of load and restriction.
Next, the general rule of orifice flow is that pressure drop is the square of flow. Doubling the flow does not double the pressure drop. It takes 2 x 2 or 4 times the pressure drop required to push twice the oil flow through any orifice/valve/hose/fitting.
From the prince website, the pressure drop chart lists data at a maximum of 20 gpm. Not meaning it fails to operate, just that is as far as the data goes.
http://www.princehyd.com/Portals/0/products/valves/catalog/ValvesLsRd25.pdf
It lists pressure drop for In to Out flow of 20 gpm at 11 psi pressure drop. (This is for 110 SUS oil at 115 degrees F. Of course thicker oil is much more pressure drop.) This condition would be when the valve is in neutral, just passing through center.
Passing 28 gpm instead of 20 would be roughly (28/20) squared = 1.4 x 1.4 = almost two times the pressure drop as there was at 20 gpm. 40% flow increase increases pressure drop almost two times. No big deal, still only 25 psi or so.
Now, look at shifted position. Flow goes from Inlet to A and from B to Outlet. Those are 40 and 42 psi respectively. Big jump up. But it gets worse. On extend, 28 gpm into the closed side is only about 22-25 gpm out the rod side for most cylinders. But on retract, 28 gpm into rod side is about 35 gpm out of the closed side. So on inlet, 28/20 squared is about 2 x 40 = 80 psi drop. On the outlet, 35/20 = 1.75 squared = three times the pressure drop at 20 gpm. 42 x 3 = 126 psi. Adding the inlet drop of 80 psi to outlet drop of 120 and it is over 200 psi just to move oil in and out of the valve. Lot of pressure drop and heat. Almost 10% of the system power is already going to heat before lines and fittings are considered.
Most valves will operate at much higher than rated flow, just with extra pressure drop and heat. However, at some point, the flow forces in the spool start to make it hard to move, or create side forces,
BTW, note that the same pressure drop data and the same castings are used for 1/2 and 3/4 NPT ported versions. The majority of pressure drop is through the spool and casting inside and that isn’t much different regardless of ports. So, just getting larger ports means larger holes in the adaptors, but overall it doesn’t help all that much unless you get a larger valve series with bigger holes inside the spools and casting.
Here is what I would do. (Actually, it is what I am doing…)
-grab the 16 hp twin cylinder engine while you can.
-Watch for cheap bell housing and coupling as those will be the same either way
-Run the numbers for your cylinder to see if 22 vs 28 gpm is acceptable to you
-Watch for a 30 to 40 gpm valve with detent on return. Single spool, open centered spool, with inlet relief valves, are fairly easily available at surplus center, ebay, scrap yards, or northern, but finding one with a detent is a bit harder. If you find one, let me know, I am looking for this size also for my 28 pump.
-When time comes, build all the mechanical and welding portions of the project first. If you still have not located a large valve, then buy the 22 pump instead of the 28, and the standard Prince valve.
-Alternate, buy the 28 gpm pump and smaller valve, but run at slower engine speed. That hurts the slow speed, but the fast speed is the same and the engine runs slower and quieter.
kcj
pasted in below.
VALVE RATINGS
Valve 'ratings' are a lot like 'tonnage ratings' : determined more by marketing than by an objective standard.
In case of a valve, or any flow component, it is simply an orifice at wide open. So the flow is a function of how much pressure drop you are willing to tolerate (assuming the device does not malfunction).
For example, the common Prince splitter valve is 'rated' at 25 gpm maximum. What if I put 30 into it?
First, this rating of 25 is assumed to be 25 gpm in from the pump, but remember that 25 gpm into the rod side on retract is 30 to 35 gpm out the closed side. I will return to that.
Second, it does not mean that 25 gpm passes and the other 5 gpm disappears. Since this is a positive, fixed displacement gear pump, if it moves 30 gpm, the oil has to go somewhere. So it goes through the valve. It just creates more pressure drop and load on the pump. Remember, pressure is a result of load and restriction.
Next, the general rule of orifice flow is that pressure drop is the square of flow. Doubling the flow does not double the pressure drop. It takes 2 x 2 or 4 times the pressure drop required to push twice the oil flow through any orifice/valve/hose/fitting.
From the prince website, the pressure drop chart lists data at a maximum of 20 gpm. Not meaning it fails to operate, just that is as far as the data goes.
http://www.princehyd.com/Portals/0/products/valves/catalog/ValvesLsRd25.pdf
It lists pressure drop for In to Out flow of 20 gpm at 11 psi pressure drop. (This is for 110 SUS oil at 115 degrees F. Of course thicker oil is much more pressure drop.) This condition would be when the valve is in neutral, just passing through center.
Passing 28 gpm instead of 20 would be roughly (28/20) squared = 1.4 x 1.4 = almost two times the pressure drop as there was at 20 gpm. 40% flow increase increases pressure drop almost two times. No big deal, still only 25 psi or so.
Now, look at shifted position. Flow goes from Inlet to A and from B to Outlet. Those are 40 and 42 psi respectively. Big jump up. But it gets worse. On extend, 28 gpm into the closed side is only about 22-25 gpm out the rod side for most cylinders. But on retract, 28 gpm into rod side is about 35 gpm out of the closed side. So on inlet, 28/20 squared is about 2 x 40 = 80 psi drop. On the outlet, 35/20 = 1.75 squared = three times the pressure drop at 20 gpm. 42 x 3 = 126 psi. Adding the inlet drop of 80 psi to outlet drop of 120 and it is over 200 psi just to move oil in and out of the valve. Lot of pressure drop and heat. Almost 10% of the system power is already going to heat before lines and fittings are considered.
Most valves will operate at much higher than rated flow, just with extra pressure drop and heat. However, at some point, the flow forces in the spool start to make it hard to move, or create side forces,
BTW, note that the same pressure drop data and the same castings are used for 1/2 and 3/4 NPT ported versions. The majority of pressure drop is through the spool and casting inside and that isn’t much different regardless of ports. So, just getting larger ports means larger holes in the adaptors, but overall it doesn’t help all that much unless you get a larger valve series with bigger holes inside the spools and casting.
You are so far over my head that you look like a speck on the ceiling 
.
Does all that that translate to "It's ok to use the standard 25gpm valve with a 22gpm pump who's unload is turned up to 900 on a 16hp engine."? LOL
Hydraulics are greek to me. Possibly Syrian too.
I need to go by TSC and have a look at a Speeco to see if the pump body mounts to the engine or if it has it's own mount that bolts to the splitter frame.
Ian
. Does all that that translate to "It's ok to use the standard 25gpm valve with a 22gpm pump who's unload is turned up to 900 on a 16hp engine."? LOL
Hydraulics are greek to me. Possibly Syrian too.
I need to go by TSC and have a look at a Speeco to see if the pump body mounts to the engine or if it has it's own mount that bolts to the splitter frame.
Ian
wkpoor
Addicted to ArboristSite
After reading the tutorial I am remembering a post sometime last year were someone analyzed my setup and said it wouldn't work at least on paper. I told them it had been in service for 3yrs with no problems what so ever. So when I read about the valves and there ratings I thought about how he must be talking good sense. Just like I've pointed out the marketing #'s on splitters may have nothing to do with the real actual applied force. Once a mfg asignes a # and the product sells everyone else is forced to follow suite or be left in the dust. Next thing you know Ex being all 4" cylinder splitters are 22 ton.
wk:
yup. filters and strainers are the same way. and bars on chain saws like wild things. Deteremined more by marketing than engineering.
At least in the industrial world, there are more actual data ratings, but it is tough to wade through it.
Very few things fail 1 % beyond their 'ratings'. There is just some tradeoff of pressure, flow, stress, life, cost, etc etc that is balanced out by what fits the application.
log splitters are such commodity, cookie cutter designs that as long as you do 5.5 hp, 4 inch cylinder, 11 gpm pump, etc etc it is hard to go wrong.
Venturing outside of the box takes some understanding and design skills.
ian:
not to worry, much of what I cut and post is for the larger audience that wants to really understand in depth. often ocean depth, but there are a small % out there who do.
review the first lines, what I would do, is grab the engine, do the mechanical part of the project first while continuing to look for a valve. Then if you need to, buy the pump 22 and valve at the end and slap them on.
I think I would still go 28 and run the lower engine rpm until getting the larger valve.
do you have the cylinder? what dimensions? The cycle time would determine the pump size.
Watch ebay also, 11-13-16 pumps go HIGH, within $20 of new prices often. I got stung $130 to a seller who never shipped.
But I got a used 28 Barnes on there for $25 + freight. Not many people have the engine to use the big pumps, so less competition.
yes, you should mount pump to engine. much easier to hold alignment that way. If you have a weldment machined at a shop, it may cost as much as buying the bell housing. You could shim and align, but I am suspecting that might be a little more precision than you want to get into. Although, given it runs a hundred hours in its life, not a hundred hours a week, the mount could be less precise.
Then mount the engine to the frame with isolator mounts, these Lord or Barry from Grainger are sweet, easily available, and cheap.
Another 'cut and paste' below.
kcj
ENGINE add vibration isolator mounts,
Grainger 5XK44 is a common, two piece, center bonded mount, that use a ¾ inch hole in the base, 3/8 bolts for motor mounting. (4) required, about $4 each. These are quite stiff for the weight of a 5 hp engine, but are the smallest Grainger had in stock. With steel through bolt and sleeve, and washer on both sides, the engine is positively restrained in case of rubber deterioration. Simple to use: Just drill out the original motor mount holes in the splitter to 3/4 inch, deburr and install. Raises the engine slightly. My 18 hp engine is more in the weight rating and the mounts are quite effective. I used the mounts between engine and power unit frame, and also between power unit and trailer frame. Makes a sweet and quiet running package.
yup. filters and strainers are the same way. and bars on chain saws like wild things. Deteremined more by marketing than engineering.
At least in the industrial world, there are more actual data ratings, but it is tough to wade through it.
Very few things fail 1 % beyond their 'ratings'. There is just some tradeoff of pressure, flow, stress, life, cost, etc etc that is balanced out by what fits the application.
log splitters are such commodity, cookie cutter designs that as long as you do 5.5 hp, 4 inch cylinder, 11 gpm pump, etc etc it is hard to go wrong.
Venturing outside of the box takes some understanding and design skills.
ian:
not to worry, much of what I cut and post is for the larger audience that wants to really understand in depth. often ocean depth, but there are a small % out there who do.
review the first lines, what I would do, is grab the engine, do the mechanical part of the project first while continuing to look for a valve. Then if you need to, buy the pump 22 and valve at the end and slap them on.
I think I would still go 28 and run the lower engine rpm until getting the larger valve.
do you have the cylinder? what dimensions? The cycle time would determine the pump size.
Watch ebay also, 11-13-16 pumps go HIGH, within $20 of new prices often. I got stung $130 to a seller who never shipped.
But I got a used 28 Barnes on there for $25 + freight. Not many people have the engine to use the big pumps, so less competition.
yes, you should mount pump to engine. much easier to hold alignment that way. If you have a weldment machined at a shop, it may cost as much as buying the bell housing. You could shim and align, but I am suspecting that might be a little more precision than you want to get into. Although, given it runs a hundred hours in its life, not a hundred hours a week, the mount could be less precise.
Then mount the engine to the frame with isolator mounts, these Lord or Barry from Grainger are sweet, easily available, and cheap.
Another 'cut and paste' below.
kcj
ENGINE add vibration isolator mounts,
Grainger 5XK44 is a common, two piece, center bonded mount, that use a ¾ inch hole in the base, 3/8 bolts for motor mounting. (4) required, about $4 each. These are quite stiff for the weight of a 5 hp engine, but are the smallest Grainger had in stock. With steel through bolt and sleeve, and washer on both sides, the engine is positively restrained in case of rubber deterioration. Simple to use: Just drill out the original motor mount holes in the splitter to 3/4 inch, deburr and install. Raises the engine slightly. My 18 hp engine is more in the weight rating and the mounts are quite effective. I used the mounts between engine and power unit frame, and also between power unit and trailer frame. Makes a sweet and quiet running package.
Bell housing.... one more thing I didn't know I needed. I suppose this goes between the engine and the pump and you have to get the right one that matches both.... Sounds like more money.
I'm picking up the cylinder, beam and valve at Eric's GTG next month. It's a complete 3-point hitch splitter for a tractor. Not sure on cylinder diameter.
Ian
I'm picking up the cylinder, beam and valve at Eric's GTG next month. It's a complete 3-point hitch splitter for a tractor. Not sure on cylinder diameter.
Ian
Last edited:
Two things to keep in mind is that pump adaptors are very rare for vertical shaft engines and tractor hydraulics often use a closed center valve. Stand alone splitters use a open center valve.
good points.
Open center is used with fixed displacement pump, i.e gear pump that moves oil all the time. Always say 15 gpm of flow. Goes through center to tank at very low pressure when not used.
Closed center is used with a variable displacement, constant pressure, usually piston pump. There is always say 2500 psi pressure. If no need for flow, the pump strokes back to hold pressure at almost no flow. Thus, valves have blocked center. Sort of like constant voltage in the wall outlets. You can just plug in more loads in parallel at any time and place.
Closed center on the gear pump means all flow goes across relief when not actually moving the cylinder. BIG heater and entire engine hp goes to heat.
Open center is used with fixed displacement pump, i.e gear pump that moves oil all the time. Always say 15 gpm of flow. Goes through center to tank at very low pressure when not used.
Closed center is used with a variable displacement, constant pressure, usually piston pump. There is always say 2500 psi pressure. If no need for flow, the pump strokes back to hold pressure at almost no flow. Thus, valves have blocked center. Sort of like constant voltage in the wall outlets. You can just plug in more loads in parallel at any time and place.
Closed center on the gear pump means all flow goes across relief when not actually moving the cylinder. BIG heater and entire engine hp goes to heat.
This project is getting more and more expensive all the time... 
I'm definitely going to have to start cruising ebay for cheap used stuff.
I emailed Prince to find out what model number an open center 28gpm detent valve is.
Ian
I'm definitely going to have to start cruising ebay for cheap used stuff.I emailed Prince to find out what model number an open center 28gpm detent valve is.
Ian
AKKAMAAN
ArboristSite Guru
Hi KevinJ
You really have this into a science...I read the whole thread today...50+ posts...
There are enough "pirates" out there today, I didn't want to steal the thread so I started a new one.....
http://www.arboristsite.com/showthread.php?t=97416
How big does the reservoir need to be and is an internal baffle a necessity? I've got a line on a tank off a 10gal air compressor, but putting a baffle in it would be real hard.
Ian
Ian
Crofter
Addicted to ArboristSite
You need a large enough tank so that the intake flow does not create a whirlpool to the surface and entrain air. Bad for pump, foaming etc. Baffles help prevent this if tank size is marginal. I like to see a baffled off sediment space as well so tank flow does not stir it up. The larger the tank the lower the turbulence, better cooling and easier to ensure return dumps in below surface level of the fluid.
I am sure Kevin will have some rule of thumb for capacity for a given GPM pump. The best reservoir is more than an empty tank with an inlet in the bottom and return in the top. Some systems also require a pressurized cap but you should not have to get that fancy!
I am sure Kevin will have some rule of thumb for capacity for a given GPM pump. The best reservoir is more than an empty tank with an inlet in the bottom and return in the top. Some systems also require a pressurized cap but you should not have to get that fancy!
wkpoor
Addicted to ArboristSite
My tank matches my pump volume as recommended by Prince. However I have found that it could have been 1/2 that size due to the fact that the oil just doesn't get hot like I thought it would. Splitters are really intermittent use. If I have over 15 gallons of oil in the tank the fluid will never get up to temp even in the summer time. The other thing I kinda would like to change is fitting placement. Goes outcha is lower L/H side and goes inya is upper R/H side. Sounds logical right......Wrong! Both should have been on the same side. I discovered that the inlet flow shoots clear to the other side of the tank thus doing the opposite of what I as trying to accomplish. One baffle in tank would have corrected it or just located both on the same side.
Just bought a new 28gpm pump on ebay for the price of a 22. Couldn't resist.
Ian
Ian
ericjeeper
Addicted to ArboristSite
Sweet deal.
Now you just need an axle, a tank, and an engine?
Now you just need an axle, a tank, and an engine?
Got an axle and most of a frame. A buddy of mine is donating his little trailer to the cause. He's replacing it anyway. If 10 gallons is enough, I have the tank too. Now that I have the big pump, I have mandated at least a 16hp engine. No smaller will do. It's also mandated a high flow control valve. If I have to buy one anyway because of the open vs closed center issue, I might as well buy one that will handle the pump's capacity.
Ian
Ian
Crofter
Addicted to ArboristSite
Dont forget the extra valve section to operate the block lifter you are going to want! In for a dime, in for a dollar, Lol!
I might be able to get away with the standard flow control valve. Max RPM on the pumps are 4k, which is where they rate the flow I assume. I read that at the rpm on the 17hp Kawasaki in my mower is governed to 3k, so assuming that the engine I get is similar, I will only be getting 3/4 of the rated flow from the pump, or 21gpm. I could actually get 85% of the rated flow or 3400rpm on the engine before reaching the limit of the standard 25gpm valve.
Ian
Ian
I'm sure you guys are sick of this thread, but you clicked on it again. so tough luck... LOL
My lawn mower runs at 3600 without the blades engaged, 3400 while cutting grass.
Looks like I really need the high flow valve.
Ian
My lawn mower runs at 3600 without the blades engaged, 3400 while cutting grass.
Looks like I really need the high flow valve.
Ian
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