Jerky project cylinder action

[yarg]

Hello to all,
I built a well drilling machine. It is all hydraulic and works great except for the mast cylinder.
It is a 2 inch double acting and swings a 600pound mast up and down.
Here is the issue:
1. The two way wood splitter valve seams to work fine.
2. The valve is set at 1500.
3. The cylinder causing extreme jerking of the mast up or down.
4. A1/16 orifice on either line did nothing.
5. For some reason, actuating this valve stalls the engine= 21 hp?

Your thoughts?
Thanks,
Gray

 

[J_J]

Is your pump to big for the engine?

Is there any air bubbles in the tank.

What is the cu in if the pump?

Why use a log splitter valve as the reverse is usually set around 1100 psi for auto return to neutral. .

http://www.princehyd.com/Portals/0/products/valves/catalog/ValvesLsRd25.pdf

 

[yarg]

First time project for me.
I felt the valve was for a ram= cylinder, so it must be ok?
The engine is 21hp and the pump is 1.8 ci I think.
It runs the hydraulic motors just great. Each are 23.6ci and 180 rpm.
I could get a lower pressure bypass cartrage but will that do?
Gray

 

[hosspuller]

Seems to me that intermittant motion of a hydraulic cylinder is air or variable volume of the system. Something is allowing the fluid flow to stop.

 

[J_J]

Something is not quite right here.

Can you perhaps explain a little more about the hyd system.

Using your data, and 21 HP, and a 1.8 cu in pump, that engine running at 3600 rpm would pump about 28 GPM's. That would take about 58 HP to turn that pump at a pressure of 3000 psi. AT 1500 psi, it would take about 29 HP.

On your motors using 18 GPM, 23 cu in, rpm would be about 181.

What valve are you using for the motors? One motor or two?

Are you using more than one valve?

Can you show some pictures.

You say the pressure relief is set at 1500 for something, but what?

 

[yarg]

No pics right now but I will try to explain.
I run one motor at a time.
They use at full power about 16 gpm at 1450 psi.
One runs a chain hoist with great control and power.
One turns the drill head pipe.
I use a two spool double acting valve for these functions with power beyond into a second valve.
The second valve powers the cylinder,,,,up and down.
14 inch stroke 2 inch bore.
I have not run the engine higher than 2400 rpm for break in and safety.
Finished the build two days ago and discovered the cylinder issue.
Tried an orifice on the cylinder, no good, same problem?

Ideas?

 

[yarg]

Air? I am going to bleed it tomorrow?
Could that cause such issues? It is just done and no oil through it till I tried to lower the mast.

 

[yarg]

JJ,
I must say, it is nice to be able to ask someone this sort of question.
I am in Barry remote location where few if any have knowledge to help on this.
Being my first ever hydraulic project, I was happy with it till I tried the mast ram, then the pits.
I am persistent but do appreciate a direction. Thanks for posting your ideas. And thanks to any others for sharing!

 

[yarg]

JJ

Hello again.
I was up much the night thinking of these options:
Get lower pressure relief cartage for valve,,,,500-1500?
Place a 1/32 orifice in supply line?

This may allow for engine not to stall and decrease travel speed/ force to a reliable level?
Blead all air so bouncing is not possible.

 

[J_J]

Those cyl are probably 2500 to 3000 psi cyl, so why not use the power they can generate.

The cyl is going to move at whatever lever position you set.

Don't know how much the boom is lifting, but the pressure is generated by the load that the boom has to lift. By setting the relief valve to 1500 you essentially set the load that the boom can lift before the relief will go off.

GPM's dictate the speed of operation.

If you want reduced GPM, reduce the engine rpm.

If you need to keep the engine running fast for the pump to feed the hyd motors, then you run those same GPM through the cyl, which is probably way to fast.

There is another valve called a divider valve and this one will give 2 GPM to the cyl and pass the rest of the flow to tank. It is also set to 1500 psi if that is what you want.

Surplus Center - 2/30 GPM PRINCE PRIORITY FLOW DIVIDER W/RELIEF

http://www.surpluscenter.com/Instruct/I9-4158-2.pdf

This valve would go between the motor valve and the cyl valve.

What you are doing here is to reduce the GPM's to the cyl

All OUT ports should go to tank and can be teed together.

You do have the PB adapter installed and the flow is going to the IN port of the next valve, correct.

Any air should self purge, so work that cyl about 10 times, using full cycles , feeding it small amounts of fluid by using the valve lever.

 

[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.