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  1. SU Puresonic flowmeter
  2. Performance

Excellent accuracy and repeatability with the SU ultrasonic flow meter

The SU Puresonic ultrasonic flow meter from ifm is a reliable flowmeter for multiple media types

Industrial:

For 90% water applications:

Part No. Line size 
Nominal flow rate
10% of max flow 50% of max flow 100% of max flow
Repeatability
  Accuracy (2% MW + 0.5% MEW)* (0.2% MEW)
SU6x21

½” NPT / G1/2

0.13…17.17 gpm
0.5…65 lpm

+/- 0.12 gpm
+/- 0.46 lpm
+/- 0.26 gpm
+/- 0.98 lpm
+/- 0.43 gpm
+/- 1.63 lpm
+/- 0.03 gpm
+/- 0.13 lpm
SU7x21

¾” NPT / G3/4

0.13…19.81 gpm
0.5…75 lpm

+/- 0.14 gpm
+/- 0.53 lpm
+/- 0.30 gpm
+/- 1.13 lpm
+/- 0.50 gpm
+/- 1.86 lpm
+/- 0.04 gpm
+/- 0.15 lpm
  Accuracy (1% MW + 0.5% MEW)* (0.2% MEW)
SU8x21

1" NPT / G1

0.25...63.40 gpm
1...240 lpm

+/- 0.38 gpm
+/- 1.44 lpm
+/-0.63 gpm
+/- 2.40 lpm
+/- 0.95 gpm
+/- 3.60 lpm
+/- 0.13 gpm
+/- 0.48 lpm
SU9x21

G 1-1/4"

0.26...72.64 gpm
1...275 lpm

+/- 0.44 gpm
+/- 1.65 lpm
+/- 0.73 gpm
+/- 2.75 lpm
+/- 1.09 gpm
+/- 4.13 lpm
+/- 0.15 gpm
+/- 0.55 lpm
SU2x21

2" NPT / G2

1.32...264.18 gpm
5...1,000 lpm

+/- 1.59 gpm
+/- 6.0 lpm
+/- 2.64 gpm
+/- 10.0 lpm
+/- 3.96 gpm
+/- 15.0 lpm
+/- 0.53 gpm
+/- 2.0 lpm
For 35% glycol and oil (viscosity 68mm2/s at 40°C)
Part No. Line size
Nominal flow rate
Accuracy (% of max flow) Repeatability
10% 50% 100% 10% 50% 100%  
Glycol: (5% MW + 0.5% MEW)* Oil: (5% MW + 1.0% MEW)* (0.2% MEW)
SU6x31

½” NPT / G1/2

0.13…17.17 gpm
0.5…65 lpm

+/- 0.17 gpm
+/- 0.65 lpm
+/- 0.52 gpm
+/- 1.95 lpm
+/- 0.94 gpm
+/- 3.58 lpm
+/- 0.26 gpm
+/- 0.98 lpm
+/- 0.60 gpm
+/- 2.28 lpm
+/- 1.03 gpm
+/- 3.90 lpm
+/- 0.03 gpm
+/- 0.13 lpm
SU7x31

¾” NPT / G3/4

0.13…19.81 gpm
0.5…75 lpm

+/- 0.19 gpm
+/- 0.75 lpm
+/- 0.59 gpm
+/- 2.25 lpm
+/- 1.09 gpm
+/- 4.13 lpm
+/- 0.30 gpm
+/- 1.13 lpm
+/- 0.69 gpm
+/- 2.63 lpm
+/- 1.19 gpm
+/- 4.50 lpm
+/- 0.04 gpm
+/- 0.15 lpm
SU8x31

1" NPT / G1

0.25...63.40 gpm
1...240 lpm

+/- 0.63 gpm
+/- 2.40 lpm
+/- 1.90 gpm
+/- 7.20 lpm
+/- 3.49 gpm
+/- 13.20 lpm
+/- 0.95 gpm
+/- 3.60 lpm
+/- 2.22 gpm
+/- 8.40 lpm
+/- 3.80 gpm
+/- 14.40 lpm
+/- 0.13 gpm
+/- 0.48 lpm
SU9x31

G 1-1/4"

0.26...72.64 gpm
1...275 lpm

+/- 0.73 gpm
+/- 2.75 lpm
+/- 2.18 gpm
+/- 8.25 lpm
+/- 4.00 gpm
+/- 15.13 lpm
+/- 1.09 gpm
+/- 4.13 lpm
+/- 2.54 gpm
+/- 9.63 lpm
+/- 4.36 gpm
+/- 16.50 lpm
+/- 0.15 gpm
+/- 0.55 lpm
SU2x31

2" NPT / G2

1.32...264.18 gpm
5...1,000 lpm

+/- 2.64 gpm
+/- 10.00 lpm
+/- 7.93 gpm
+/- 30.00 lpm
+/- 14.53 gpm
+/- 55.00 lpm
+/- 3.96 gpm
+/- 15.00 lpm
+/- 9.25 gpm
+/- 35.00 lpm
+/- 15.85 gpm
+/- 60.00 lpm
+/- 0.53 gpm
+/- 2.0 lpm

Sanitary:

For 90% water applications:
Part No. Line size 
Nominal flow rate
10% of max flow 50% of max flow 100% of max flow
Repeatability
  Accuracy (1% MW + 0.5% MEW)* (0.2% MEW)
SUH20x

1" Tri-clamp

0.25...63.40 gpm
1...240 lpm

+/- 0.38 gpm
+/- 1.44 lpm
+/-0.63 gpm
+/- 2.40 lpm
+/- 0.95 gpm
+/- 3.60 lpm
+/- 0.13 gpm
+/- 0.48 lpm
SUH40x

2" Tri-clamp

1.32...264.18 gpm
5...1,000 lpm

+/- 1.59 gpm
+/- 6.0 lpm
+/- 2.64 gpm
+/- 10.0 lpm
+/- 3.96 gpm
+/- 15.0 lpm
+/- 0.53 gpm
+/- 2.0 lpm
For oil (viscosity 68mm2/s at 40°C)
Part No. Line size 
Nominal flow rate
10% of max flow 50% of max flow 100% of max flow
Repeatability
  Accuracy (5% MW + 1.0% MEW)* (0.2% MEW)
SUH20x

1" Tri-clamp

0.25...63.40 gpm
1...240 lpm

+/- 0.95 gpm
+/- 3.60 lpm
+/-2.22 gpm
+/- 8.40 lpm
+/- 3.80 gpm
+/- 14.40 lpm
+/- 0.13 gpm
+/- 0.48 lpm
SUH40x

2" Tri-clamp

1.32...264.18 gpm
5...1,000 lpm

+/- 3.96 gpm
+/- 15.00 lpm
+/- 9.25 gpm
+/- 35.00 lpm
+/- 15.85 gpm
+/- 60.00 lpm
+/- 0.53 gpm
+/- 2.0 lpm

Note: Performance specifications of the ultrasonic flow meter are true across the full temperature rating of -4...212°F (-20...100°C).
* MW = measured flow rate; MEW = full range flow rate

Accuracy and reliability calculation examples

Most of ifm’s flow meters use a two-part accuracy calculation, based on the measured flow rate (MW) and full range of the meter (MEW). For example, accuracy of the SU8621 (MEW = 63.40 gpm) is specified as:

± (1 % MW + 0.5% MEW)
             For MW = 50 gpm, accuracy = ± (0.01*50 + 0.005*63.40) = +/- 0.817 gpm

The repeatability calculation is consistent over the entire flow measuring range of the unit. For example, repeatability of the SU8621 (MEW = 63.40) is specified as:

± (0.2% MEW)
repeatability = +/- (0.002*63.40) = +/- 0.1268 gpm