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Selection Chart

QuadraTherm® iSeries Mass Flow Meters

World's Most Accurate Air / Gas Mass Flow Measurements

Use the selection chart below to evaluate the various flow ranges that are applicable to the QuadraTherm 640i insertion probe version and QuadraTherm 780i inline flow body version.  The ranges shown are optimal minimum/maximum ranges for air. Meters will read to zero flow with some decreasing accuracy. Flows shown are based on ANSI schedule 40 pipe and a maximum mass velocity of 60,000 SFPM 100:1 Turndown.

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How to read this chart

Pipe Size
QuadraTherm® Mass Flow Meters for Gases
Greater than
8"
>>> (Virtually Unlimited Max Flow Rate)
QuadraTherm 640i for High Performance Applications 640i
Chart
8"
208* scfm
20,820 scfm
780i
640i
6"
120* scfm
12,060 scfm
780i
640i
4"
53* scfm
5,304 scfm
780i
640i
3"
31* scfm
3,078 scfm
780i
640i
2"
14* scfm
1,401 scfm
780i
640i
1.5"
8.5* scfm
852 scfm
780i
1"
3.6* scfm
360 scfm
780i
0.75"
2.1* scfm
213 scfm
780i
0.5"
1.2* scfm
117 scfm
780i
Graphs not to scale.
Flow
Note*
Ranges shown are optimal minimum/maximum ranges for air.
Meters will read to zero flow with decreasing accuracy.
Maximum mass velocity 60,000 sfpm
Flow rates based on ANSI schedule 40 pipe
100:1 turndown
LOW FLOWS: Under 35 scfm (1000 slpm) Click Here