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Can anybody show me the correct way to work out this question, including working. Thanks
Calculate the corrected meter volume form the following;
Meter gauge pressure = 20kPa
Atmospheric pressure = 101.3kPa
Measured volume shown on meter = 3000m3
Formula; P1 x V1 = P2 x V2
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hi,if you can make sense of this good luck, but contacting one of the tutors at the open poly might be an idea. hav`ent done this sort of thing for a long time but found this on the net. as i said before the knowledge and exams we as gasfitters are required to know is overwhelming, give it a go,cheers, post the answer if you find it. i notice that no one is offering the clues!
Can anybody show me the correct way to work out this question, including working. Thanks
Calculate the corrected meter volume form the following;
Meter gauge pressure = 20kPa
Atmospheric pressure = 101.3kPa
Measured volume shown on meter = 3000m3
Formula; P1 x V1 = P2 x V2
APPENDIX A
Combining Boyle’s Law and Charles’ Law gives the relationship:
P1 V1 = P2 V2
T1 T2
This equation states that the volume of a given mass of gas will vary inversely with the absolute pressure and
directly with the absolute temperature. By solving this equation for V2 (selling volume at agreed base pressure and
temperature), the value of the gas can be calculated:
V2 = P1 V1 T2 or V2 = V1 x P1 x T2
P2 T1 P2 T1
Note: Values indicated by subscript “2” are standard conditions. Values indicated by subscript “1”
are existing line conditions. All pressures and temperatures must be expressed in terms of absolute.
For example, find the standard volume (or selling volume) which has passed through a meter given
the following information:
V2 = Selling or Standard Cubic Feet Volume (SCF), unknown.
V1 = Final Counter Reading - Initial Counter Reading
= 1,862,900 - 1,743,600 = 119,300 Actual Cubic Feet (ACF).
P1 = 18 psi Gauge Pressure + 14.4 psi (Average Atmospheric Pressure)
= 32.40 psi Absolute Pressure.
T1 = 460 + 80 (°F) = 540 Absolute Temperature
P2 = 14.73 psi Absolute Contract Base Pressure
T2 = 460 + 60 (°F) = 520 Contract Base Temperature
V2 = V1 x P1 x T2
P2 T1
V2 = 119, 300 x 2.2 x .963 = 252,749 SCF
= 119,300 x 32.40 x 520
14.73 540
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Here goes Matt,
pressure factor = base pressure+gauge pressure divided by base pressure
101.3 + 20
_________
101.3 = 1.197
True meter volume = meter reading x pressure factor
3000 x 1.197 = 3591 cu m
Think you'll find this is correct, i know it doesn't make much sense with the given formula but that pretty much sums up the crap that we have to deal with.
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hi ade, Good stuff buddy, this is the sort of info that we all need and can share, once we know it we can keep it for reference, cheers.
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Hey ade thats awesome thanks alot!
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awesome job Ade,
You've made that really easy to understand how you've just interpreted that equation
Thanks for your help!