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.