Hydraulic pressure head question

[bigike]

I've got an issue. I have a HPU that under normal operation is set to 207bar (3100psi) and it has an extreme pressure setting of 300bar (4500ish). The HPU is 150 feet below the cylinder that it acts on. The piping that was installed has a working pressure rating of 3100 psi, not the sch 160 that was called for. It's only rated for 207. So we are replacing it, problem is that some engineers now believe that because of the Head, we need a pipe rated for 345 bar..........

This makes no sense to me because I've always believed that if you have 3000 psi and the pump you've got 3000 psi at the cyl until you spool a valve.

Now I understand that flow will be down, but these are 400LPM VD pumps and flow will not be a issue.

So is it true that by increasing the length of the pipe you increase the pressure at the top.

And if you could increase the pressure at the top, that would increase the pressure throughout the entire system. And that just couldn't happen because I've got a pilot blocker system that sets my VD pump to certain pressures through a PRV. And even if it did increase the pressure, I would never see it because the PRV would catch it and dial the pump back................ I hate engineers some times.....

Hope I didn't confuse anyone...........:dontknow:

Thanks
Jay

 

[ARRESTmeRed04]

makes sense to me, doesn't it have a valve that would bleed off PSI if it went to high like a blowoff valve on a turbo setup, i can't remember the name of the valve but i think tractors and such have them because the PSI will spike over the PSI rating of the system if your carrying a load in the bucket and hit bumps

 

[DevilDawg3097]

pressur relief valve, thats there way of thinking in theory your right but they are throwing in a safety factor if your system is set at 3000 psi all piping and lines will be rated to handle 3500 - 4000 just incase there is a spike and the prv goes bad or sticks close when it should be releaving pressure. Safety is always a 1st issue with me but for once the engineers are right. believe me I would love to get a bunch of them fuggers in a room, some of the shit the come up with.

 

[bigike]

There is a pilot blocker system that controls the stroke/displacement of the pump I can set it with the prv to any pressure. On the cylinder there is a dual sensing valve set to 350 bar that is in case the system is operating and it takes a kick from the cmc (crown mounted compensator). It works on both ends of the cylinder.

With a working pressure of 4410 (300bar) The burst pressure on the pipe is like 20,000 psi............... LOL

I believe it is a CYA but it's done because the guy doesn't know any better.... I'm gonna go piss some excellence on them at the meeting tommorrow and show them why BigIke is the lead hydraulic tech!

 

[OSO]

Lets put in terms you can relate to . If you have a trans rated at 500hp and have a 500HP power plant in front of it will work but reliability becomes an issue because of load, wear and fatigue . Now if you have one rated at 1500HP and still only have the 500Hp power plant reliability increases and Jay gets to drive his truck

 

[Silverback]

Drawings would need to be provided to fully understand this. Otherwise any answers you may receive could have overlooked something.

 

[bigike]

I think i might be able to......... Meeting is in the morning.

reckon i ought to get some sleep, its 2300 sunday night here