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Flow calculation table

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wfsymon

Industrial
Oct 16, 2011
10
I'm looking for a table or list of conversion factors to use to calculate natural gas flow from a Barton dp recorder. As I understand, you take the square root of static line pressure X differential flow (in inches of water), and then multiply by a conversion factor for the line diameter and orifice diameter. I commonly work with 2" and 3" gas injection lines. Can anyone help provide, or point me in the right direction?



Regards,
symon
 
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call a supplier of orifice plates they'll calculate the meter factor and formula for you
and maybe sell you a new plate down the road
 
I assuming the flow rate for the DP is a known (assumptions kill, huh?)

It's not the sq rt of the DP, it's the sq rt of the DP normalized to percentage.

And you need to know the flow rate at 100% of the DP, at the top of the chart scale, which I'll designate 'max flow'.

The DP is normalized to percent; 0-100% across the chart range.

The square root of the normalized percentage is the percentage of flow rate.

So, picking round numbers to make it quick and easy

sq rt 100% DP = sq rt 1.00 = 1.00 = 100% of max flow rate
sq rt 81% DP = sq rt 0.81 = 0.90 = 90% of max flow rate
sq rt 64% DP = sq rt 0.64 = 0.80 = 80% of max flow rate
sq rt 49% = sq rt 0.49 = 0.70 = 70% of max flow rate

You get the idea.
 
It took me a week to find a scan of an old square root circular chart.

Back when people used mylar sheets for overhead projector slide presentations, I knew a guy who used the mylar sheets to create a flow scale overlay for his recorders that were mechanically configured to record only linear DP charts, 0-100%.

He drafted square rooted flow scales (like below) where the graph grid lines are labeled with flow values on the major divisions onto a mylar sheet.

He would overlay the transparent mylar over the DP linear chart and read the trendline against the mylar flow grid lines.

The graph below is an image of true legacy, an antique Brown (now Honeywell) with square rooted flow chart scales

35i22rp.jpg
 
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