2 stage pump question

[CincyFlyer]

I will look at it, didn;t know that possibility. But I cannot find any "stackable" pumps at surpluscenter.com Can you give me link plz, I only find stackable valves!:confused2:

EDIT: If I am correct I found some on surpluscenter that are called "multi-section" pumps, but their cost is 4 times the "normal" pump! baileyshydraulics do not have them at all, so it looks like thats a dead end for me

You can always belt or chain drive multiple pumps; sprockets, chain, belts and pulleys are cheap.

 

[muddstopper]

I think you are going about your design backwards. You are trying to choose pump and eng without looking at actual flow/pressure requirements. I would sit down and make a list of all the functions you want for your processor. If a hyd chainsaw is in the plans, find a motor and sprocket combo that will do what you want. Then add the cyl circuits for lowering the saw and clamping the log and decide how you want them to work, will it be all manual with a CV for each function, or are you considering using sequence valves to make the circuits work with just the pull of one lever. Are you going to have a conveyor to advance the log, and maybe a conveyor to carry off the splits. You also have the splitting cyl, how big and how fast do you need it to run. are you going to have a hyd adjustable multi split wedge, thats another circuit to consider. Once you figure out how much hyd flow and pressure is required to make everything work, then you can choose the pump and engine combo. If you decide to go with the 16hp engine, and two stage pump, be prepared to have a lot of start and stops, speedups and slow downs during the operations and two stage pumps arent exactly friendly as the high flow side of the pump is low pressure which limits the power of the saw and when the pump kicks into the high pressure side, it makes the saw pretty dang slow. You might want to consider using a gas chainsaw to buck the logs onto the splitter. there are a lot of homemade processors made that way as a way to reduce cost and eliminate fooling with a lot of hyd design.

 

[polemidis]

I think you are going about your design backwards. You are trying to choose pump and eng without looking at actual flow/pressure requirements. I would sit down and make a list of all the functions you want for your processor. If a hyd chainsaw is in the plans, find a motor and sprocket combo that will do what you want. Then add the cyl circuits for lowering the saw and clamping the log and decide how you want them to work, will it be all manual with a CV for each function, or are you considering using sequence valves to make the circuits work with just the pull of one lever. Are you going to have a conveyor to advance the log, and maybe a conveyor to carry off the splits. You also have the splitting cyl, how big and how fast do you need it to run. are you going to have a hyd adjustable multi split wedge, thats another circuit to consider. Once you figure out how much hyd flow and pressure is required to make everything work, then you can choose the pump and engine combo. If you decide to go with the 16hp engine, and two stage pump, be prepared to have a lot of start and stops, speedups and slow downs during the operations and two stage pumps arent exactly friendly as the high flow side of the pump is low pressure which limits the power of the saw and when the pump kicks into the high pressure side, it makes the saw pretty dang slow. You might want to consider using a gas chainsaw to buck the logs onto the splitter. there are a lot of homemade processors made that way as a way to reduce cost and eliminate fooling with a lot of hyd design.

I have not done any design yet, other than the common log spillter with the 2stage pump. My question on the very first post was placed in order to figure out if that approach was realistic. Since it isn't, I can now do what you mention. The only restriction is that I already have a 16hp gas engine. If this is not enough for my needs, then maybe I will consider using that pump to the splitter, and go with a bigger motor for everything else.

Anyway, thank you all guys, I think that thead is covered. If I am not too much pain, I will open another one later with more specific questions/ or even a review if everything goes well! Its a whole journey, and the more I research the more confident I feel, (and the more I realize of how many things I do not know!!!!!)

EDIT: Can you give plz more info on the sequence valves you mentioned? How does this work? I was planning on manual valve for each function, didn;t know the alternative you mentioned:confused3:

 

[polemidis]

You can always belt or chain drive multiple pumps; sprockets, chain, belts and pulleys are cheap.

You are right. I just feel that a jaw coupling and a pump mount is so easy. With belts, chains etc, I will need so manymore parts to fabricate, and too much detail is needed that I believe will make everything too complicated. And a 16hp motor will not be able to handle all that without compromises in the speed of the operation. I will just add another gas engine for a second circuit for the splitter.. But thanx for mention it. I hadn't thought of that option!

 

[muddstopper]

EDIT: Can you give plz more info on the sequence valves you mentioned? How does this work? I was planning on manual valve for each function, didn;t know the alternative you mentioned:confused3:

Sequence valves do exactly as the name implies. they are cartridge type valves, that allow you to use just one control valve to operate multiple functions in a set sequence. For EX. You pull the lever on your control valve and the log clamp cylinder clamps the log at which point a set pressure is reached. when that pressure is reached the second function in the sequence starts to move, lets say the saw cyl starts to move, it to will reach a set pressure and then the saw motor will start to run. Return the cv to retract and the saw will stop running, the saw cyl will lift and the log clamp will release. A good sequence manifold with appropriate cartridges will run you around $500. They are also finicky to keep adjusted, especially if you process large wood and small wood at the same time.

Just to give you a starting point, because I dont know what your actual needs might be, let me pass along some info.
Saw motor. forget trying to find a saw motor that will turn super high rpms. Eveybody seems to think that they need a Parker bent axis motor that will turn 8000rpms to make their processor saws work. Nothing is farther from the truth. Chain speed is what you need to obtain, not motor speed. bent axis motors need large volumes of oil and to reach those rpm ranges, and they also need high pressures to have any torque. If you look at the majority of processors out they, they mostly use gear motors, and the manufacturers tend to over flow the oil a little to get the speed. A gear motor will have more torque than a bent axis, but it wont turn the rpms.. gas powered chainsaws run 9000rpms, some more some less, they turn the chain using little 7pin sprockets and reach high chain speeds. You slow turning gear motor can run a much larger sprocket and if matched with motor speed, can reach the same or similar chain feet per minute as those bent axis motors and those small sprocket, engine screaming gas saws. If you have a favorite gas powered chainsaw you like to cut with, choose a gear motor and sprocket combo that will yield similar chain speed and you will be satisfied with your hyd saw performance. If you still think you need a bent axis motor, I have a new rexroth bent axis motor I will sale for $500, which is less than half you will pay for a similar motor if you buy from a supplier.

I would also consider using a double pump setup for powering everything. Separate pumps to run the saw and splitter. Log clamps and conveyors are momentary operations and neither function will be used while sawing a round. You can rob oil from the saw when it isnt in operation to run your logclamp and conveyor. Now if you insist in using a small gas engine to run your pumps, you can use power beyond control valve and a dump valve to create a high/low pump setup to speed up your splitter cyl. The dumpvalve would be placed after the saw motor CV and before the splitting CV. and would only function when the saw motor is not turning. The advantage is that you have full oil flow for the saw when needed, and when not needed the oil will all flow to the splitter and act like a two stage pump. The dump /unloader valve will supply all the saw motor oil to the splitter until pressure reaches a set point and then is diverted back to tank to reduce the Hp requirements of your engine. Benefit is you get fast speed until you need the force and then the unloader valve diverts the saw oil to tank and you have high pressure for those tuff splits. This would allow you to size you engine to power the largest splitter pump at the max pressure your engine can pull.

 

[MossRoad]

Prince SPD2 costs $430+. Too much. It will cost a lot less with a 2nd engine design. For the splitter I can use a cheap engine, I think 12hp is more than enough.

Playing devil's advocate here...

One more motor to purchase.
One more motor to maintain.
One more pump-to-engine mount to purchase.
One more lovejoy connector to purchase.
One more engine mounting location to increase the size of the unit.
Two times as loud.
Two times fuel consumption (not scientific).
Two fuel lines.
Two "hot locations" to keep away from.
Two mufflers to purchase.
You'll need twice the fuel tank capacity (if the motors don't come with fuel tanks).
And you'll need twice the fuel storage capacity to get the same amount of working time, so add in a second gas can, or double the trips to the gas station.

Add all those costs up and see if it totals 1/2 of the $430 that seems too much at first glance. And I'm probably leaving some stuff out.

Make your materials list both ways and see how they add up on a spreadsheet.

 

[muddstopper]

With the right setup, you can do a lot more with a 16hp engine and a high low pump setup than you might think but there is a compromise. The 28gpm 2 stage pump only rated for about 900psi at full flow. Then it drops down to about 8gpm@3000psi. I aint going to do all the math, but using 2 single stage pumps with a unloading valve would allow the use of up 12gpm@2000psi, which should be enough flow and pressure to run a hyd chainsaw with one pump and set the other pump at 8gpm@3000psi for high pressure for the splitter and with the combined flow still have 20gpm for high speed. The compromise is you only have 20gpm at low presssure instead of 28gpm with the two stage pump. The advantage is you are able to pump enough oil at a decent pressure range to run a hyd chainsaw. The 12 gpm@2000psi will get you in the ballpark using one of these motors, .7 cu in Parker MGG2-BB1B3 Hydraulic Motor | Parker | Brands | www.surpluscenter.com, which personally I think would be the minimum size motor I would use for a hyd chainsaw. Going with a 20hp or larger gas engine would allow for a better motor as well as bigger pump choices. A 25hp engine will get you in the 18gpm@2000psi for a chainsaw motor and would allow you to use a 1.2 cu.in axial piston motor and make about 23hp of chainsaw. Throw a big 14pin sprocket on the saw motor, a ,404 chain and cut with the big boys. You would also be able to run a 18/12 double pump setup and potentialy have 30gpm of oil to split with. Anyways, just a few thinks to think about.

 

[tcreeley]

I bought a mini backhoe a while back with a 6hp engine. It was slow. I swapped out the 6hp for an 8 hp tecumseh. The original pump was a 1.2 GPM single stage. I swapped that out with a 11 GPM two stage. Just moving the bucket around into position was faster and when it came to digging it dropped down to 1.5 GPM. I was pleased with the outcome. Much faster. Plenty of power. Bought it new and it has done a lot of digging, Frostline is 4-5 feet - done well.

 

[polemidis]

Playing devil's advocate here...

One more motor to purchase.
One more motor to maintain.
One more pump-to-engine mount to purchase.
One more lovejoy connector to purchase.
One more engine mounting location to increase the size of the unit.
Two times as loud.
Two times fuel consumption (not scientific).
Two fuel lines.
Two "hot locations" to keep away from.
Two mufflers to purchase.
You'll need twice the fuel tank capacity (if the motors don't come with fuel tanks).
And you'll need twice the fuel storage capacity to get the same amount of working time, so add in a second gas can, or double the trips to the gas station.

Add all those costs up and see if it totals 1/2 of the $430 that seems too much at first glance. And I'm probably leaving some stuff out.

Make your materials list both ways and see how they add up on a spreadsheet.

because I already have some stuff sitting adding the costs it will be a lot cheaper to go with 2 motors, but the other points you mentioned make sense. Thats why I asked about using the 2-stage pump. Now with muddstopper's suggestion I think I will go back to 1 engine, -if and when I absorb all that info-. All that stuff are new to me!

With the right setup, you can do a lot more with a 16hp engine and a high low pump setup than you might think but there is a compromise. The 28gpm 2 stage pump only rated for about 900psi at full flow. Then it drops down to about 8gpm@3000psi. I aint going to do all the math, but using 2 single stage pumps with a unloading valve would allow the use of up 12gpm@2000psi, which should be enough flow and pressure to run a hyd chainsaw with one pump and set the other pump at 8gpm@3000psi for high pressure for the splitter and with the combined flow still have 20gpm for high speed. The compromise is you only have 20gpm at low presssure instead of 28gpm with the two stage pump. The advantage is you are able to pump enough oil at a decent pressure range to run a hyd chainsaw. The 12 gpm@2000psi will get you in the ballpark using one of these motors, .7 cu in Parker MGG23-BB1B3 Hydraulic Motor | Parker | Brands | www.surpluscenter.com, which personally I think would be the minimum size motor I would use for a hyd chainsaw. Going with a 20hp or larger gas engine would allow for a better motor as well as bigger pump choices. A 25hp engine will get you in the 18gpm@2000psi for a chainsaw motor and would allow you to use a 1.2 cu.in axial piston motor and make about 23hp of chainsaw. Throw a big 14pin sprocket on the saw motor, a ,404 chain and cut with the big boys. You would also be able to run a 18/12 double pump setup and potentialy have 30gpm of oil to split with. Anyways, just a few thinks to think about.

My needs: I want to sell about 30cords per year from 10in dia logs that I am thinning from my forest. This year I sold 12 cords with manual bucking, lifting the wood, put it on my cheap HF 2-way splitter, split it, throw them down, then picking them by hand, load them to the bucket, and fill the trailer. For the last part I already designed the grapple to pickup thefirewood, so I will eliminate one manual chore. So any basic firewood processor, even with the slowest cutting will be a huge improvement, in safety, fatigue, and time. Huge. I am not picky, I will be thankful with anything that will automate that process no matter how slow it will be. On the other hand I do not want to invest so much yet, because the volume of the logs that I can sustainably harvest is 30-40 cords, no more, so I want to be able to cover the cost of the machine soon.


I believe I read already all the firewood processor posts on this forum, I didn't notice anyone doing that. Everything else about the .404 chain, avoid these T11 motors, a 14-15sprocket I got them. I was targeting the 0.58 motor for the saw, so we are on the same page here.

Give me some time to understand your suggestion about the 2 pumps. I am new to that stuff, do not forget!!! :newhere: You mean to hook up 2 pumps with some mechanical way, like chain/belt right? I have to do my homework on the new terms "unloading valves" "sequence valves":shocked:

Plz do not give me any new info!!!!!!!! Let me digest that first! :drink:

 

[muddstopper]

Save the .404 chains for the bigger saw motors, I doubt the .58cuin motors will pull a .404 anyways. The two pumps are mounted end to end. The first pump connects to the engine shaft and the second pump connects to the back of the first pump. You will need two control valves. The CV for the saw will be multi spool to operate several functions and must be power beyond capable. The second control valve would just be single spool if all you want to control is the splitting cyl, but if you add a adjustable wedge or a auto cycle valve, then it might have multiple spools and it doesnt need to be, but can be, power beyond. To make the hi/low pump system work, your would run a line from the PB port of the saw valve to the unloader valve and between the unloader valve you would need a check valve and then to a tee in the pump side of the splitter control valve. You will also have to run a return line from the unloader valve back to tank. You set the main relief on the saw valve to the required pressure for the saw motor and you would set the unloader pressure a couple hundred psi below the main relief setting for the saw. So if you need 2000psi for your saw to work, set the main relief there and the unloader at 1800psi. this will prevent any oil flow over the relief while splitting. The unloader valve will direct oil to the splitter valve until the 1800psi is reached and then divert the oil to tank. The splitter pump will continue to build hyd pressure up to what ever the main relief on the splitter valve is set at. Its not that complcated, but there are some other things to consider, such as sizing the control valves to handle the oil flow.