firewood conveyor question

[muddstopper]

I cant figure out why a conveyor would need/use a 2 stage pump. The 11gpm pump only puts out 500psi at high flow. 11gpm at 500psi and only needs 3.6hp to pull the pump. A 11gpm single stage pump should pull the conveyor very well with a 6hp predator engine, belt speed would be a matter of throttle on the engine and you could turn up the pressure if you found the conveyor needed a little more power. The detent valve off the old splitter should work well to keep the conveyor running and if set properly should kick out if the conveyor gets stuck.

 

[muddstopper]

For what it is worth, I run the Honda 160 GX at a little over half throttle.

Flow control valve.
I run the belt at approx. 25% of max. speed. So I'm thinking, I'm only putting 25% of the pump output to use and the rest, 75% of the oil flow, is bypassing, returning through the third port of the flow control valve to the tank.
So for example, what if your pump puts out 11 gpm. and your hydraulic motor uses 8 gpm. max. The 5 hp engine may be struggling to push the extra 3 gpm somewhere and it can't. (not sure hydraulic motors have gpm limits that way) The 6.5 hp may not be bogging, but without a bypass it just burning extra fuel. I would think the oil would heat up, except with the style tank you have it probable would dissipate the heat rather quickly. The hoses might get hot though.
Not sure that's how it works, just guessing.
I could bypass my flow control valve to see but... that's not going to happen.
Maybe kevin j or someone else can jump in again.

Sand you posted while I was typing, To answer your question about pumping more oil than the hyd motor is rated for, its a yes and no answer. The hyd motors are rated for a certain amount of flow based on the cuin capacity of the motor. The more cuin of oil that is supplied, the faster the motor will turn. Its kinda like that old 350 chevy engine, it will turn rpms until something breaks and that is what will happen when you start turning that small hyd motor more rpms than it is meant to turn. Now some of the hyd chainsaws on processors do overflow the oil to the saw motors to increase chain speed, and that's ok but does reduce the lifespan of those motors. As for you using only 25% of the oil flow and the rest bypassing, that's not exactly true either. If you are running your engine at 25% of max speed, then you are only pumping 25% of pump capacity. Again, the pump flow is determined by the cuin of oil pumped every revolution. The faster it turns the more oil it pumps, low rpms means low flow. As for bypassing your flow control, you already have it so why not keep using it. If you didn't have one, I think I would just adjust throttle to control my speed, no extra oil being pumped and no unnecessary heat build up.

 

[Sandhill Crane]

I understand the motor and pump ratings are for 3,600 rpm.
Disconnecting the flow control would be to simulate Ptsiteworx situation to see if my 5 hp would bog down. I really don't want to go to that trouble, but would be interesting.
The flow control, being three ports, must bypass some oil back to the tank.
The directional valve bypasses oil when in neutral.
I'm assuming an oil restriction is bogging Ptsiteworx 5 hp engine, based on my 5hp being large enough to run a conveyor.

 

[Sandhill Crane]

In ArboristSite Trading Post, Large Equipment Matt Fleck has a Timberwolf 20' conveyor (now sold), and apparently from the pictures does not have a flow control valve.

 

[Ptsiteworx]

when i called cord king to see what gpm or other specs their conveyor had they didn't really know only that they can run off their processors. j they said they sell a power pack for it that has a 14hp motor for $2400 lol

even if i have to throw an 8 or 10hp motor id still come out way ahead.

btw i only paid 1500 for the whole conveyor

 

[muddstopper]

I understand the motor and pump ratings are for 3,600 rpm.
Disconnecting the flow control would be to simulate Ptsiteworx situation to see if my 5 hp would bog down. I really don't want to go to that trouble, but would be interesting.
The flow control, being three ports, must bypass some oil back to the tank.
The directional valve bypasses oil when in neutral.
I'm assuming an oil restriction is bogging Ptsiteworx 5 hp engine, based on my 5hp being large enough to run a conveyor.

No way I can diagnose his problems setting in my recliner. I don't think you trying different connections on your machine is going to simulate his problems either. You are correct in that your flow control is returning some oil back to tank, altho being the tightwad I am, I probably wouldn't add a flow control to a conveyor I might own. Unless the hyd pump is also powering some other function at the same time the conveyor is running. Not having any clue as to how much power a conveyor needs to operate my thoughts turn to what would cause the engine to bog. First things first, what condition is the engine in. If the motor wont run, or barely runs, it is probably going to have a hard time pulling a pump. How much oil is the Pump putting out, Pressure isn't a concern until actual work is being performed. What is the pressure relief setting, is it set for more than needed to run the conveyor. The engine will bog as soon as flow and pressure reaches the hp output of the engine. If pressure is reaching the relief setting, Why? Is something putting the conveyor in a bind or is it being overloaded. Hard to tell from just a picture, but one thing I would check is his quick connects and make sure they are plugged all the way in and oil isn't being restricted at that point. I have seen brand new ones that connected but didnt seat properly and restricted oil flow. Not often, but it does happen. If he is using the cyl hoses and control valve off the old splitter and just hooking the hoses to his hyd motor, and everything worked when it had the cyl mounted, those quick connects would be the first place I checked.

 

[Ptsiteworx]

so I checked over everything again today and found that i had overfilled the oil on the new predator motor when i installed it so it wasn't running properly. got the level down and tested it out and it runs the conveyor good. I wouldn't be surprised if that old briggs ic motor was down to or less than 3hp by now

 

[Sandhill Crane]

Good to hear.

 

[quantico]

I have never even seen a wood splitter run.. let me ask a dumb question ?? On my several hydrostatic tractors the hand motion lever goes stop to full forward or full reverse. If i slam the lever in the center the tractor slams to a stop. With a wood chipper does the hydro pump run fully and the motion for the ram forward or reverse just use part of the fluid ?? What happens when the ram hits fully open or closed ?? How does the machine handle that ??

 

[muddstopper]

I have never even seen a wood splitter run.. let me ask a dumb question ?? On my several hydrostatic tractors the hand motion lever goes stop to full forward or full reverse. If i slam the lever in the center the tractor slams to a stop. With a wood chipper does the hydro pump run fully and the motion for the ram forward or reverse just use part of the fluid ?? What happens when the ram hits fully open or closed ?? How does the machine handle that ??

I suspect if your tractors are slamming to a sudden stop, you will soon be replacing expensive parts. Try easing off the control lever so things don't just slam when stopping or changing directions

Without getting into a lot of technical terms, A control valve is just a way to direct oil flow. You have two types of control valves, open center and closed center. When the lever is in the center position, oil passes thru the control valve back to tank in a open center CV, which is what is normally on a wood splitter. When the lever is moved, the spool inside the CV will direct oil either to one direction or the other of an actuator, ( hyd cyls or hyd motors are considered actuators). The oil flows thru one port and to the actuator and out the opposite port back to CV and back to tank. If the cyl is fully retracted or hyd motor is blocked from turning, oil will flow back to tank thru a relief, usually, but not always, built into the CV. When the valve is again returned to center position, the spool in the CV will block both ports to the actuator, which would cause a sudden stop as the oil path is blocked from actuator to tank. You also have what is called a motor spool valve which allows fluid to flow between the ports, but not back to tank. This is usually found where a hydraulic motor is being used and allows the motor to coast to a stop instead of slamming to a stop.

There are several variations of control valves, the open center I have described and the closed center one I already mentioned. With this type of control valve, the oil from pump does not pass thru the valve when in the center position. These closed center valves are usually found on equipment that use load sensing and variable displacement hyd pumps. Basically, when the CV is centered, no work is being done and the pumps are not pumping any oil. I don't know of anybody building simple wood splitters that use variable displacement pumps. The CV valve will still function the same as a open center valve as it relates to the lever and the spool and a lot of open center valves can be converted to a closed center valve with the addition of special plug that blocks the return port and redirects the return oil thru an additional port.