Jerky project cylinder action

[bigdeano]

Yarg - Gray,

Sounds like you have it under control. I was thinking last night you need to restrict the down movement too. Will be interesting to hear how it works. Post some pics when you get it drilling.

J-J,

You're right, the pressure takes care of itself, but with so much flow it was trying to accellerate the heavy mast so fast it was developing enough pressure to open the relief. With the much lower flow the pressure should be steady and determined by the weight of the mast.

Mace,

The problem was apparently caused by the cylinder trying to raise the mast in something like a half second. The lack of valve feathering capability seems strange, but maybe that's the way the log splitter valve is made. I've never messed with them. It will be interesting to see what finally fixes it.

 

[J_J]

HYDAC USA : Hose Break Valves/Velocity Fuses

Hydraulic fuses add safety and control to circuits | Other Technologies content from Hydraulics & Pneumatics

 

[J_J]

bigdeano,

Whoever is operating the valve is in control of how much fluid to let in. If I wanted the cyl to go slow, I would barely move the lever.

Actually, I would use a very small flow going into the valve.

Even if your pump is 20 GPM, you have the ability to only let say 2 GPM into the work circuit, and the rest of the fluid just flows through the valve with no or very little pressure. .

I believe the flow should be separated anyway between the valves.

 

[yarg]

Hello,

I understand JJ's point. Yes, the pressure is based upon the need but when this valve with 1500 PSI stalls the pump then I must drop the working pressure of this valve to not damage the engine or pump and the ram does not need that much pressure. The proportioning valve is a good sulution and so is CJone's "vlocity fuse" as I think he means needle or oriface valve? This way if I hard plumb this at the base of the ram, I will protect from a damaging or injurious sudden mast drop from a hose rupture? I think that is his point.
A perfect fix is all of those parts: A low pressure relief cartridge, a needle valve and a propotioning valve.

I have the first two ordered and may order the third as well.
This thread deserves a report and I will do so.

 

[yarg]

bigdeano,

I could not feather that valve no matter how I tried. The only way I got a reduced flow to the ram was with the use of the motor spoon bleading off the bulk of the flow. That valve is fast, I mean fast acting. On or Off.

Mace is right, it wanted to jump the mast up so fast, it was scarry and dangerous and even could have been damaging as well.

Gray

 

[yarg]

Those fuses are more complex internally. I can see why they work the way they do.

 

[bigdeano]

Hello,

I have the first two ordered and may order the third as well.
This thread deserves a report and I will do so.

If you're going to use the proportioning valve with the needle valve you need to consider this. If you throttle the flow with the needle valve below the rated flow from the controled flow port, the valve will apply the full system pressure to the needle valve trying to maintain the rated flow. your main relief valve will open to limit the pressure.

If you're going to use it like this you probably want the model of proportioning valve with it's own pressure relief valve so you can set it at a lower pressure and reduce the load on the engine. You can buy them either with or without the relief valve.

I would try first with the parts you have ordered already, it will probably work fine.

Check on ebay for hydraulic flow control valves, you might save some money. I bought a new one for 30 dollars once.

 

[J_J]

If you get anywhere close to the 1500 psi, you will stall the engine.

1100 psi will probably stall that 21 HP engine.

It is hard to keep going with this as things are not matched up. You are having to make adjustments after the facts, using what you have .

There are ways to make almost anything work, but you should not have to do that. We could call it bailing wire, or band aids.



This is not to different from matching all the parts for a log splitter from scratch.

From the pump matched to the engine, to the manual log splitter valve to the auto valves matched to the GPM's of the pump. Log lift perhaps as an aid to the work cycle.

Hoses matched to the ports or pump valve and cyl.

Selecting the filter and tank to hold the fluid.

Selecting the cyl to give the expected splitting times and the power in tons to get the job done.

If done right, there should be no add on's to help make the system work.

 

[bigdeano]

J.J.

The lower relief cartridge setting should fix the stalling. I worked as a design engineer for about 10 years, not everything works perfectly the first time. You just have to keep working on it until the problems are fixed. All the new 787's are grounded because of a battery problem, somebody screwed up. All they can do is fix the problem and keep going.

 

[yarg]

I knew the engine was going to be underpowered for the pump but thought the flow for the motors was more important and the ram was way more tan I needed. The stall came as the biggest and only surprise. A1.3 or 1.5 ci pump would have worked but then a higher engine speed woukd be needed for the rpm range. In a perfect world I would have purchased a 450$ more engine for the 6 extra hp but I will not need that. Now I am paying 85$ for these two parts? Theseparts woukd have been needed even with a larger engine.
Yes, we learn from mistakes as most do. In the hundreds of choices and decissions made to design and build this from scratch as my first hydraulic and gas welding project, I will not appologize for making this mistake. I also enjoy this learning process, it beats the h. Out of my formal classes!
I just went to the tech part of the surplus center site that JJ just posted!
Nice resource, if I had seen it before sellecting I may have gotten a 1.3 ci pump but at least I see it now.

 

[bigdeano]

Yarg,
I think you've done an amazing job on your drilling rig. As problems go this is a very small one. You had it almost fixed I think when you put the 1/16 restrictor in the line. If the engine hadn't stalled it probably would have worked.

If you decide to buy a flow control valve take a look at ebay auction 300867377287

 

[yarg]

Thank you very much. Some friends really like it and I am hoping it works well too but with 2 ft of snow on the ground and temps in the teens, this will be some time I made my own restrictor from a coupling with a hex drive plug ground to allow It to go to the middle of the coupling. All I had was a 1/16 bit and I saw some on a hydraulic site with 1/32 inch orifice. It takes a week to get anything here so I improvised a bit. I could tell it helped but just too big a hole. The fittings were only 3 bucks but shipping was 12? I chose the needle valve hoping to be able to dial the right speed.

Can not wait for the parts!

 

[bigdeano]

yarg,

I thought of a way to simplify this. Since you're using the needle valve to control the ram speed, all you need is a pressure relief valve set at maybe 600 psi in the line from the motor valves to the ram valve. It will take much of the load off the engine when you're raising the ram. No proportional valve is needed. All the excess flow ends up in the tank anyway, this would just be simpler and cheaper.

If your engine doesn't labor too much while raising the mast, you don't even need this additional valve.

 

[yarg]

Bigdeano,

In reality, tat is the result of my plan.

Needle valve and a low oreasur relief cartridge in the ram spool. This cartidge will do this very thing but when neither valve is working there will be no back pressure to speak if os the engine can just idle.
Hope I have this right?
Gray

 

[bigdeano]

I thought you were going to put the 1000 psi relief cartridge in the motor valve. Sounds like you have a good plan.

 

[yarg]

I thought you were going to put the 1000 psi relief cartridge in the motor valve. Sounds like you have a good plan.

Yes, I am putting the cartridge into the ram spool valve. Any time I actuate this valve the max pressure will flow to the ram and the excess will flow though the relief and to the tank.

The motor spool is upstream of the ram spool and thus can have the 1500 psi the motors are rated at. The power pack I have will produce enough for either motor to have full power and about 25% extra if needed if I run both for any reason at once.

I did come up with one more question while reading a thread on a float valve:

I have a float spool on the motor valve. I got this configuration so that if I was running the chain hoist motor in the down travel mode, I could put it in float and allow the wieght of the drill head and pipe to travle freely for drilling force. I have tried the float possition and it does not do this??? What am I missing here?

Gray

 

[J_J]

In float mode, all ports are common.

You will have no force, as all fluid goes to tank.

Think what happens with float on a loader, the bucket just follows the contour of the ground.

With enough weight on the motor drive, it might try and make a pump out of the motor.

 

[yarg]

JJ,

That is what I thought would happen but the head is 200 pounds and this is not enough to move the motor? It puts about 200 inch pounds of rotational force on the motor by my calculations. Maybe it needs to work in a bit or needs a bit more wieght?
I have a Kubota L48 and nderstand the float function but thought that it would not take much force to overcome the friction---I may be wrong.

Gray

 

[bigdeano]

The hyd motors I have were very hard to turn when new. You could try pulling down on the head to add more weight. I seem to remember that some float valves only open one work port to the tank port, so like a blade it can float up but not down. Not sure about this though. If you can't get it to move you could try reversing the hoses.

 

[yarg]

You know, I thought it might just be a friction thing. Being brand new, those motors are not broke in if that even happens?
My float in the tractor does both up and down but the static pressure is likely higher than on these motors.
I will try a load on the head to see if I can move it then I should know what to expect?

I do not really need this feature but it would be nice to have.
I am thinking it will work
No parts today? Getting antious!

Update: just got back from my shop and I checked if the float woukd work with additional weight. It does but the motor sounds like a bucket of bolts when you lever the head to move in float ( engine off). Sounds like it has to break in to smooth out and react under lesser load?
Gray