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Air Leak

05/28/2013 7:33 AM

dear viewers

As a part of leakage test

I would like to know about compressed air pressure drop calculation from air leak. In our compressed air system in a leakage test it found that there is a leak of 4.375 m3/minute. Then how can I find pressure drop from this leak. We have no instrumentations for pressure in compressed air line ,please help me is any relation or equation of pressure drop calculations from leak

It's very urgent waiting for replay.

Compressor details are

Compressor capacity (m3/minute) = 35 (1236.01 CFM)or 2100 m3/hour

Cut in pressure, kg/cm2 = 6.8

Cut out pressure, kg/cm2 = 7.5

Load kW drawn = 188 kW

Unload kW drawn= 54 kW

Average 'Load' time =1.5 min

Average 'Unload' time = 10.5 min

Pipe diameter - 100 NB (4inch, 101.60mm)

Length of the pipe - 320m

regards

rahul

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#1

Re: air leak

05/28/2013 7:44 AM

It looks as though the air leak represents 1/8 of the capacity of the compressor, and the compressor is only loaded 1/8 of the time. Therefore, the only reason this compressor runs is to sustain the air leak.

The pressure drop will therefore be from the cut out pressure to the cut in pressure over 1.5min.

It would save a lot of power if it were to be switched off until the leak has been fixed.

Engineering isn't about <...urgent...>. It's about 'considered'.

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#2
In reply to #1

Re: air leak

05/28/2013 8:12 AM

Dear sir

thank u for replay

please explain more about

"The pressure drop will therefore be from the cut out pressure to the cut in pressure over 1.5min"---- pressure drop calculation

rahul

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#4
In reply to #2

Re: air leak

05/28/2013 9:34 AM

This information was given in the original post!

All one can say is that the average pressure drop is between 0.4 and 0.5kg/m2/min (to 1 sig. fig.).

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#7
In reply to #2

Re: air leak

05/28/2013 11:07 AM

Never mind the calculations. Is the leak fixed yet?

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#3

Re: Air Leak

05/28/2013 9:15 AM

"We have no instrumentations for pressure in compressed air line"

Really? Not even a simple gauge?

Put a pressure gauge in the line. Simple!

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#5

Re: Air Leak

05/28/2013 10:25 AM

Psssssssssssssssssssssssssssst! Fix the leak!

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#8
In reply to #5

Re: Air Leak

05/28/2013 11:10 AM

Too logical.

It is much more (Insert favorite word for misguided, illogical, waste of time here) to perform meaningless calculations that will prove nothing.

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#16
In reply to #5

Re: Air Leak

05/29/2013 1:17 AM

thank a lot all for replay and advices

actually we are starting corrective actions immediately for fixing leak.

As a part of preparing an internal air audit report i must need pressure drop so i asked how i do pressure drop calculation in a leaky air line. its a must for us

please any one can help us a precise measure for it.

its a kind full request to experts in this area pls help me

regards

rahul

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#17
In reply to #16

Re: Air Leak

05/29/2013 2:30 AM

Plumb a pressure gauge into the line, get a stop watch and measure the ACTUAL pressure drop over time, and know for sure what the pressure drop is.

The fact that you are, "preparing an internal air audit report" indicates that your function is not a productive one.

At this point, you are an impediment, not a solution.

Leak rate calculation - Prosensys GmbH

How to Convert from Pressure Decay to Leak Rate - Inficon

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#18
In reply to #17

Re: Air Leak

05/29/2013 3:09 AM

It's amazing how much unproductive effort can be involved in fixing things these days. Still, it keeps people off the streets...

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#21
In reply to #18

Re: Air Leak

05/29/2013 3:14 AM

As you said earlier, fix the leak. End of story.

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#6

Re: Air Leak

05/28/2013 11:04 AM

I am in and I raise you a:

FIX THE LEAK!

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#9

Re: Air Leak

05/28/2013 12:04 PM

It probably isn't his job to fix the leak, it's the maintenance departments. It needs to be calculated to determine the proper amount of fix.

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#10
In reply to #9

Re: Air Leak

05/28/2013 12:11 PM
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#11
In reply to #9

Re: Air Leak

05/28/2013 12:31 PM

Maybe they can install a $5.00 USD pressure gauge while they're repairing the leaks, and negate the need to do unknown calculations.

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#12
In reply to #11

Re: Air Leak

05/28/2013 5:45 PM

now, don't you think that would be too easy?

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#13
In reply to #12

Re: Air Leak

05/28/2013 7:01 PM

As easy as finding a 154 CFM leak I would think!

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#14
In reply to #12

Re: Air Leak

05/28/2013 7:50 PM

Yes, and I have considered what you said about his position within the company.

I must agree with you that it isn't his job to actually fix anything.

I believe that he is the manager of the Department of Redundancy Department.

His job must be to convince management to do things. He needs figures to prove his case and of course all documents look more official if the calculations are there to justify the cost.

I worked in a DoRD once. Our "urgent" motto was: "There's never enough time to do the job right, but there's always enough time to do it over.

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#22
In reply to #14

Re: Air Leak

05/29/2013 8:20 AM

thank you for your replay

actually you are mistaken me ,i am also responsible for preventive maintenance activities even i posting my situations in forum i also taken corrective action for fixing leak by coordinate maintenance department.

at same time i am all ways try to link one parameter with other i know that air leak is cause of pressure drop but for a good auditing report i investigate more things

i think its a right job?

most fun is its our compressor that already shut down for maintenance activity so its a time for investigate more things

thanks for ur advice and support

rahul

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#15

Re: Air Leak

05/28/2013 10:27 PM

This a real issue, or disguised homework?

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#19
In reply to #15

Re: Air Leak

05/29/2013 3:11 AM

It's a shame there isn't a Good Question button, really.

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#20

Re: Air Leak

05/29/2013 3:12 AM

Is the leak fixed yet?

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#23

Re: Air Leak

05/29/2013 2:09 PM

Okay if you have no pressure gauge how then do you know the cut in and cut out pressure? Usually on a compressed air system there are devices that utilize the air. There is some device to regulate the pressure to them. How do you set the regulation with out a gauge?

How was the leak test preformed? In most cases with out a flow meter. The test is done with the time between cut out to cut in and the volume of the system. With out a gauge your test maybe way off.

Anyway your wasting 12.5% of the energy to compress air because of the leak. As other have recommended fix the leak.

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#24

Re: Air Leak

05/30/2013 2:20 AM

May be you can explain which pressure drop is for you of interest:

- the one at the leak

- the one between the two pipe ends

- or an other

It is not clear at least for me what you want.

To fix the leak is an economic problem and should be done as soon as possible.

Now if you have no air tools connected to your system and the compressor cycle depends ONLY on the leak the problem can be solved only if the different reservoirs connected to the pipe are known as volume. I presume that the compressor delivers to a reservoir which is connected to the pipe and at the other end the pipe is also connected to a reservoir from which go the connection to users. The fact that the compressor uses near to 30 % of power in the low pressure range seems to indicate that you have some consumption but not much.

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#25

Re: Air Leak

10/16/2024 7:13 AM

Is the leak fixed yet?

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