Loader limits and relief valve?

[azuerch]

Hello,

I've not a new Kioti NX4510 that I put a grapple on. I was using it move some logs that were dropped of at my property. A couple of the logs were so large that I could barely move them. I grabbed them with the grapple and went I went to curl/lift it was very slow but did slowly lift them enough to move around. I am trying to understand what is happening and make sure i'm not damaging my machine.

Is this the relief valve activating due to the large load?
I assumed the relief was all or nothing so why was I still able to slowly lift it?
Is this normal behaviour?

I looked up relief valves online and it looks like it is poppet/spring type that is tuned to activate above a certain threshold. Does regular operation of the relief valve weaken the spring reduce performance of the system?

THanks,
Aaron

 

[ericm979]

I've had the same experience with heavy logs in the grapple. And also being able to lift something only part way. It's normal. The loader is designed so it has the most lift capacity at ground level and the least when raised up all the way.

The relief will open just enough to limit the pressure to the valve's opening pressure. I.e. if it trips at 2500 psi the system will be able to maintain 2500 psi.

I trust that the engineers have set the relief pressure low enough that reaching is is far short of damaging parts. Though you should have the load roughly centered rather than all on one side, so you dont' twist the loader.

Tripping the relief wont' hurt anything. If you dead head a valve and leave it there, all the flow will be through the relief. That will heat up the fluid. So it's not a good idea. But when you do dead head a valve nothing after it in the chain works, so you'll notice it eventually.

 

[LD1]

Sounds normal for lifting at capacity.

The relief is NOT all or nothing. Its a spring. So the closer to max you get...oil can get past the relief but not all of it. So you can still lift, but slowly.

AS far as the spring getting weak....I suppose if you had a super precise way of measuring it then maybe. But as far as real world results are concerned...no you arent hurting it and no its not gonna get weaker in any way that you would notice

 

[azuerch]

Thanks for the confirmation. It maybe a noob question but I wanted to understand how it works and make sure i'm not overdoing it.