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Help me with a term regarding air pressures

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#1 bmiller

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Posted 10 July 2013 - 04:59 PM

You have a compressor/storage system with a working pressure of 6,000psi. It is used to fill cylinders to 4,500psi. 

What is the term for the difference between 4,500 and 6,000? Reserve working, head space, differential, bacon?



#2 hard aground

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Posted 10 July 2013 - 05:01 PM

Overage?



#3 Ancient_Mariner

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Posted 10 July 2013 - 05:15 PM

Extra air.

#4 Figment

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Posted 10 July 2013 - 05:19 PM

mojo.



#5 miscut jib

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Posted 10 July 2013 - 05:24 PM

flatulence



#6 hobot

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Posted 10 July 2013 - 05:24 PM

The enviroment.

#7 mustang__1

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Posted 10 July 2013 - 05:36 PM

vaginaboob.



#8 atoyot

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Posted 10 July 2013 - 05:43 PM

"Overhead" pressure comes to mind, but darned if I can find a cite or other relevant guidance to justify the opinion. 

 

 

 

Looking around, though, got me wondering what the pressure of these puppies are set to - 

 

 

1.jpg



#9 bmiller

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Posted 10 July 2013 - 05:55 PM

Ummmm those are set to stun!



#10 Speng

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Posted 10 July 2013 - 06:04 PM

The differential pressure is 1500 psi...

 

in the boobs i dunno. I prefer mine more low pressure.



#11 bmiller

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Posted 10 July 2013 - 06:06 PM

OK I'm using the term in this context.

 

Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 



#12 Cruisin Loser

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Posted 10 July 2013 - 06:40 PM

Safety Factor



#13 Adventurelad

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Posted 10 July 2013 - 07:19 PM

psid, d = differential

 

http://en.wikipedia....ure_measurement



#14 BrianM

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Posted 10 July 2013 - 07:42 PM

Because it is faster?  If your compressor topped out at 4500, jamming the last few pounds in will take forever.  Someplace there's got to be a chart of air flow in CFM vs differential pressure between compressor output and flask.



#15 Point Break

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Posted 10 July 2013 - 07:53 PM

OK I'm using the term in this context.

 

Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 

Cascade system for breathers?



#16 NACRADUDE

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Posted 10 July 2013 - 08:27 PM

OK I'm using the term in this context.

 

Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 

It's pressure differential.

 

You need the additional pressure for the pressure drop in the transfer process I would imagine. YMMV here as I have never worked with air pressure that high.



#17 mad

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Posted 10 July 2013 - 08:34 PM

Pressure drop......ooops

#18 Figment

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Posted 10 July 2013 - 08:40 PM

ok, you actually have a few terms in play here.    The additional pressure is simply the differential, aka "delta-P".

 

This applies to your tank-filling scenario because it's a factor in the flow coefficient (Cv) of the transfer.

 

Cv = Flow times the square root of (specific gravity / delta-P)

 

(sorry, I don't know how to get a square root symbol and other mathematical expressions to show up on a forum)



#19 NACRADUDE

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Posted 10 July 2013 - 08:49 PM

A good source of this type of info is a Cameron Hydraulic Data book. Damn thing is my bible for Mechanical Engineering.



#20 bmiller

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Posted 10 July 2013 - 09:10 PM

OK I'm using the term in this context.

 

Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 

Cascade system for breathers?

Yep, trying to convince staff we need to replace a 35 year old machine.



#21 Point Break

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Posted 10 July 2013 - 09:51 PM


OK I'm using the term in this context.
 
Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 

Cascade system for breathers?
Yep, trying to convince staff we need to replace a 35 year old machine.
I'd call one of the big vendors and chat with a salesman. My experience is they have the process of explaining system capacity and performance nailed and will help for free (goodwill). The big points to make are reliability, historical and projected cost of maintain/repair, part availability, and on the operational side the capacity and speed to refill bottles expressed as a first alarm, second alarm etc. assignment. How many 15 to 20 minute cycles can the full assignment utilize before the incident is out of air relative to fill time of the cascade supported by the compressor.

#22 bmiller

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Posted 10 July 2013 - 11:15 PM

 

 


OK I'm using the term in this context.
 
Trying to explain why you need 6,000psi in storage to fill 4,500psi cylinders. 

Cascade system for breathers?
Yep, trying to convince staff we need to replace a 35 year old machine.
I'd call one of the big vendors and chat with a salesman. My experience is they have the process of explaining system capacity and performance nailed and will help for free (goodwill). The big points to make are reliability, historical and projected cost of maintain/repair, part availability, and on the operational side the capacity and speed to refill bottles expressed as a first alarm, second alarm etc. assignment. How many 15 to 20 minute cycles can the full assignment utilize before the incident is out of air relative to fill time of the cascade supported by the compressor.

I'm actually trying to tie into a request to transition to the 5.5 operating system. The rest of it the have a pretty solid grasp on.

 

Our older Bauer says "Made in West Germany", that should give an idea how old it is.



#23 4knotSB

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Posted 10 July 2013 - 11:34 PM

Made in West Germany is probably why it's still running.



#24 Willin'

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Posted 10 July 2013 - 11:36 PM

For conversation's sake, I'd refer to it as residual pressure. Technically differential is correct when discussing two different pressures, but the point you're trying to make is that it's practical to store 1500 PSI of residual pressure to facilitate faster jamming. That's how I'd express it.



#25 puffyjman

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Posted 11 July 2013 - 12:26 AM

This thread is useless until our resident Cliff Clavin chimes in with his take on this.
Oh wait it did have tits, I take it back it is a good thread.

#26 Black Dog

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Posted 11 July 2013 - 01:08 AM

Reserve Capacity



#27 Ancient_Mariner

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Posted 11 July 2013 - 05:02 AM

Those are some mighty big tires your inflating.... :lol:



#28 Headntac

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Posted 11 July 2013 - 05:27 AM

Great tits..... ^_^



#29 Ancient_Mariner

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Posted 11 July 2013 - 06:55 PM

Yeah...feel just like bowling balls.  No thanks.



#30 atoyot

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Posted 11 July 2013 - 10:46 PM

tumblr_mpsic0BBre1ri7ljko1_250.gif

#31 Figment

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Posted 12 July 2013 - 02:21 PM

Capacity is pressure times volume.   

 

A 1 gallon tank at 6000psi does not have the capacity to fill a 5 gallon tank at 4500psi.

 

100 gallons at 6000psi is a whole other matter.

 

atoyot wins.    Fantastic capacity.



#32 atoyot

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Posted 13 July 2013 - 01:22 AM

It's always nice to have a little left over even when you think you're done.





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