OT: Need help finding part # - OKK machine

[Dustball]

I'll preface this by saying I have a limited knowledge of hydraulic accumulators in general. Increasing the pressure won't make it work "faster"- it'll increase the pressure that the accumulator will provide when needed.


If it's charged at 1000 psi, it'll give 1000 psi back to the hydraulic system when called upon. If it's charged to 1600 psi, it'll give 1600 psi when called upon. It's similar in to a pressure tank in a well water system.


If your hydraulic pump is 2000 psi and your accumulator is charged to 1600 psi, you'll have 2000 psi in the accumulator when the pump is running but the accumulator will exert 1600 psi on the hydraulic fluid when the pump isn't running.

 

[kamenges]

Not quite. You are correct that the accumulator will act like the pressure tank in a well water system. But if you watch how those actually work from an empty state you will see what alive15 described a couple posts back. The pressure climbs relatively quickly until the accumulator precharge pressure is reached. At that point the pressure increases much more slowly as the accumulator is filled from the pump. The accumulator will rise as the gas volume is compressed as the oil volume is increased.

On discharge, the opposite will happen. The gas pressure decreases as oil volume decreases until the accumulator pressure reaches the precharge pressure. At that point the accumulator has no more oil to provide and system pressure will fall very quickly.

Increasing precharge pressure simply increases the pressure where the accumulator bottoms out. Increased precharge does allow you to store a larger volume of oil at a higher pressure but if you don't need that oil at a higher pressure it can be coounterproductive.

The real indicator would be does the clamp motion decrease in speed significantly as the accumulator pressure drops from 2000 PSI to 1000 PSI. If so then a higher precharge might help, although you would probably want to operate at a higher pump pressure as well. If not, then increasing precharge isn't going to help at all.

Keith

 

[lfe]

What should be determined is the minimum pressure that the accumulator must maintain in the clamp, this is the pressure at which the accumulator gas should be precharged.
According to your explanation it seems that the old one was precharged at 500psi

The problem is that if you preload it to 1600 psi if the pressure drops below 1600 it will suddenly drop to 0.

I think maybe it should be exchanged for a smaller one and precharged at 500psi, if you want it to fill faster.

 

[kamenges]

It doesn't sound like he needs it to fill faster. It sounds like he wants it to discharge faster. Or, more specifically, he wants his clamp to close and build pressure faster. His thinking is that higher available pressure will make that happen.

This didn't sound like an accumulator problem before the accumulator was replaced and it still doesn't sound like an accumulator problem after is was replaced. Something else is going on here. Without having a schematic available it will be a little tricky figuring out what. The thing I find a little interesting is it sounds like the pump is being disconnected from the system before the clamp is being engaged. And why is the hydraulic pressure only incrementing by 500 PSI per actuation? If it ultimately gets to 2000 PSI it sounds like the accumulator barely discharged.

Keith