Jerky project cylinder action

[yarg]

JJ,
Thank you for your input. I will ponder your info and let you know what I tried.
I will attach pics so you may see what this is all about?

Gray

 

[CJONE]

Along with JJ comments I will add a log splitter valve does not have a load check [transition check] so with a suspended load it will try to drop before you actuat the control valve all the way. Like JJ said without being there it is hard to tell but you may want to look into a valve with a transition check. I have a lot of experience with building water well rigs and oilfield rigs and have ran into transition check issues with cheap valves. For that matter I have had to remove a few to allow back spooling on wireline units. CJ

 

[wdchyd]

Bouncing to me indicates air to me also.....it may be just the cylinder design/setup not allowing any air pockets to flow back to tank (somehow tipping the cylinders to face the ports up may help with air pockets)

similar to a fork lift cyl, they have bleeder valves on top to bleed off air

You may wanna install adjustable flow control valves ( HydraStar Flow Control Valve — 1/2in. | Adjustable Flow Valves| Northern Tool + Equipment ) to meter-out the flow coming from the cylinder during stroke

The beauty of these are you can adjust on the fly to tune your system rather than putting restrictors with unknown results

 

[yarg]

I understand but I thought the seller said all these valves have load checks? I will double check that aspect. If I have this info right. The valve will allow a flow through it unchecked to the return line before the work line is flowing and in doing so it allows the suspended wieght to cause the ram to move. With a load check there would have to be some force on the return owrk line before the ram would move? Do I have this right? I will have to check my vlave specs to see if this is missing the load check feature.

 

[CJONE]

Another quick thought with a suspended load you may have to put a restictor [flow control] in the down side of a circuit. Restrict the flow of oil leaving the cylinder so it will not cavitate. Do not restrict both side of the cylinder you will just make the cavitation worse. CJ

 

[CJONE]

I understand but I thought the seller said all these valves have load checks? I will double check that aspect. If I have this info right. The valve will allow a flow through it unchecked to the return line before the work line is flowing and in doing so it allows the suspended wieght to cause the ram to move. With a load check there would have to be some force on the return owrk line before the ram would move? Do I have this right? I will have to check my vlave specs to see if this is missing the load check feature.

Yes that is exactly how it works. Basically you have to have pressure on the A line then it will allow the B line to drain back to tank. Without it the load will drop until the valve is actuated enough for the oil pressure to "catch" the load. With a log splitter valve there is no "load" to catch so they don't usually put a load check in. Now if it is a mono block 2 spool valve it would have it. Unfortunatly "log splitter valve" can be a universal term for hydraulic valve. CJ

 

[CJONE]

Wdchyd is on to it, that is what I think is happening also. CJ

 

[J_J]

If you have a load check valve, it is to prevent the cyl moving while shifting only.

The log splitter valve does not have load check valve.

Like I said before, if it does have air in it, and it seems hard to remove, then just remove the cyl and place it horizontal with the cyl ports up, and cycle the valve about 5 times.

If you continue to have air, you may have a suction leak, a cavitating port.

Do you have a good filter on the return line to tank? You want very little back pressure.

I would recommend this valve for cyl, and it does have load check.

Surplus Center - 1 SPOOL 20 GPM PRINCE RD-2575-T4-ESA1 DA OC VALVE

If your 2 in cyl has 1 in shaft, and boom cyl is at about 45 degrees, at 3000 psi, you would have a push force of 6,664 lbs,m and pull force of 4,998 lbs.

AT 1500 psi relief setting, you would sstill have about 3,332 lbs push.



.

 

[yarg]

I have a 30 gpm return filter on a 1 inch line. I have a 1 1/4" tank to pump line. I doubt there is cavitation?
Can a load check be added to a valve?

 

[J_J]

Cavitation occurs when you force large amounts of fluid through small orifices such as relief valve, and cyl ports, etc.

How much GPM is flowing through the motor valve and cyl valve.

I would think if you try and shove 16 GPM into a 2 in cyl, it might react plenty fast and jerky.

That diverter valve would solve that problem.