Homemade processor saw issue

[Chipy]

Hi, I'm from the UK and I'm struggling to get any advice on solving the issue I'm having with my hydraulic saw. My father in law has built me this one of a kind machine to cut a 10 foot log into 5 foot, then split it into 4 pieces and then bundle it into a 1.8 cubed bundle for my 200kw boiler. Il explain the issue I'm having then il put some pictures up of it and a video. Basically I'm struggling to get the same valve to operate the saw and the ram pushing the saw down and up. I have the pipe to the ram t'eed off from the flow to the saw motor and before the ram I had a needle flow control valve to change the speed of the ram which worked...... only problem was if I had the control valve turned up so that the ram came down quite fast, the saw would stall when it got into the wood because it pulled itself through too fast whilst being pushed too fast. If I turned the control valve right down to about setting 1 just before the saw hit the log then the saw would pull itself through perfectly without stalling. I can't leave control valve at setting 1 because saw takes ages to come down to the log. I'm aware that most processors you can buy, work absolutely fine but I just don't how they are set up in order for the saw not to stall but still come down at a decent speed. I've also tried giving the saw motor and saw ram there own valves so I can control them independently. By doing this the saw worked better and faster but my saw was going up and down way too fast and I was going to break something if I'd carried on using it. I only had to push my lever a tiny bit to operate the saw. The problem with controlling them independently is it's taking up 2 of my valves and I don't really have 2 spare. I'm hoping you guys can advise me how to set it up so that 1 valve will set the saw going, will operate the ram for the saw and will supply oil for the bar. I currently have a pipe t'eed into the flow pipe to the saw motor which supply's oil to the saw bar and it has a needle flow control valve to adjust amount of oil to the bar.

 

[muddstopper]

Not sure I understand your plumbing methods, but you cant tee off the pressure lines to control two operations at the same time. The pressure will take the path of least resistance making one operation fast and the other operation stop stutter and jerk. You can use flow dividers to split the hydraulic flow into two separate fluid streams. Priority flow dividers will split flow into one dedicated stream and a residual stream where the primary stream is generally regulated to a set amount and the residual stream gets whats left over. Some saw operations might could be operated using the return oil flow, such as the saw lift cyl which would be a low pressure operation. You could plumb the return oil from the saw motor thru the control valve for the saw cyl to provide the low force requirment needed to raise and lower the saw.

We also need to know if your hydraulic system is a closed center or open center system. Some of those small loaders use close center hydraulic systems and that makes things a lot different in how auxcillary functions are plumbed.

 

[Chipy]

Mine is an open centre system. I actually have a priority control valve which I haven't used yet. I understand what your saying when you say I shouldn't tee off to other functions off the flow pipe and I kind of confirmed that was an issue when I gave the saw ram its own valve and tried it but ideally I want 1 valve to operate the complete saw and ram. How do all these other processors control there saw rams? They all seem to come down quite fast and still fly through the log. If mine comes down fast it stalls when it hits the log because it's forcing its way though.

 

[olympyk_999]

Mine is an open centre system. I actually have a priority control valve which I haven't used yet. I understand what your saying when you say I shouldn't tee off to other functions off the flow pipe and I kind of confirmed that was an issue when I gave the saw ram its own valve and tried it but ideally I want 1 valve to operate the complete saw and ram. How do all these other processors control there saw rams? They all seem to come down quite fast and still fly through the log. If mine comes down fast it stalls when it hits the log because it's forcing its way though.

when we built ours we set it up with the hand lever (valve) only controlling the saw cylinder, and a limit switch controls a solenoid valve for the saw motor...
so when you actuate the saw cylinder and the saw bar moves it comes off the switch and the saw motor starts, and when it goes back to upright position it shuts off...
you need 2 separate valves to make it work properly!

 

[muddstopper]

I think most of the factory processors use a sequenceing valve. The SV is set up in stages using one flow but several sections all with different pressure setting. Typical, when you operate the Control valve, the SV will direct flow to a log clamp cyl until it reaches a set amount of pressure. At that point the pressure dumps, sort of like a relief, to the next function which would be the saw cyl to raise and lower the saw, again a set pressure is reached and the oil then dumps to the saw motor to make the saw run. One control valve to operate all three functions. A good sequence valve will run about $500 and can be aggravating to get setup/adjust properly, but they make performing multiple functions, in a proper sequence, pretty trouble free. I know I said they work sort of like a relief, but dont bother trying to connect several relief valves together to make a sequence valve, sort of is not the same as.

 

[Chipy]

Do you mean something like this http://www.flowfitonline.com/hydrau...ce-valves-12?gclid=CKS7yPj558sCFZUW0wodPy4MUA

 

[muddstopper]

That is one type and would allow you to do 2 operations with just one valve. The ones usually found on processors are a little more involved for more than just 2 operations. I dont know what £ 59.10 inc VAT is in American money, but the price seems reasonable, provided the 1/2in ports will handle the flow for your saw motor. I dont know what size you saw cyl is or the stroke, but using this valve will still provide full flow to the cyl so it will still be very fast. You can slow the cyl down by using restricted fitting to meter the flow of oil to the cyl, you will probably have to use a restricted fitting on both cyl ports to control speed up as well down. You could also use a flow control provided you get one that controls flow in both directions. You can set the pressure at the sequence valve to control down pressure on the cyl. You will need to make sure that the pressure at the cyl is low enough so that it doesnt brake off the bar studs. Down force on bar is normally under 100lbs and depending on the size of the cyl, you might have to get the actual pressure down to less than 100psi. I dont know if the valve you posted is capable of that. If it is, the saw cyl would receive the set pressure and the saw would receive system pressure.