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ST50/ST51 Series Insertion Mass Flow Meters

Mass Flow Meter ST50 and ST51

Mass Flow Meter ST50 and ST51 literature
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Mass Flow Meter ST50 Download

Mass Flow Meter ST51 Download

Mass Flow Meter Summary

The ST50 Series Flow Meters are an accurate, easy to install, no moving parts mass flow meter solution. Model ST50 is used for compressed air and nitrogen flow. Model ST51 is used for measuring biogas, digester gas, methane and natural gas. The ST50 Series utilizes FCI proven thermal dispersion technology to provide direct mass flow measurement resulting in higher performance at a lower cost than orifice plates, DP, Vortex shedding and other thermal devices. The meter installs in line sizes ranging from 2 to 24 inches [51 to 610mm] with 1/2" or 3/4" NPT.

The ST50 Series uses precision, lithography structured platinum RTD sensors embedded in FCI's equal mass small diameter, all metal thermowells. Combined with microprocessor electronics and precision calibration, the ST50 achieves excellent accuracy, fast response and virtually maintenance free operation.

Model ST50 Applications


Model ST51 Applications

Wastewater Treatment Aeration Control   Landfill Gas Recovery (LMG)
Blower and Dryer Air Flow Control   Wastewater Treatment Plant Digester
Burner and Furnace Air Flow Control   Coal Mine Methane Recovery
Lake, Pond and Aquaculture Aeration   Livestock and Dairy Farm<br>
On-Farm Biogas Recovery
HVAC Duct/Damper Control   Biogas: Biomass Fermentation and Recovery
Compressed Air Distribution Measurements   Biomass Gasification
Air/Compressed Air with totalized flow


Model ST50

Model ST51

Media Compatibilty

Agency Approvals

(IEC EX: ST51 only)

Output Signals
Dual 4-20 mA Analog
0-500 Hz pulse for totalizer

Digital Display (optional)

Air, Compressed Air, Nitrogen

Class 1, Div.2,
Groups A,B,C,D;

Zone 2
II 3 G EEx nA IIT6
II 3 D T65C


LCD, 9999 counts, user
scaleable to flow rate
enginering units or 0-100%.

Biogas, Digester Gas, Methane,
Methane Composition Gases, Natural Gas, Air, Compressed Air, Nitrogen

Class 1, Div.1, Groups B,C,D,
Class 1, Div.2, Groups A,B,C,D;

Zone 1
II 2 G Ex d IIC T6...T3,
II 2 D Ex tD A21 IP67


LCD, 2 line x 16 Characters. First
line is flow rate and engineering
units. Second line user selectable
as temperature or flow totalizer,
or alternating.

Pipe/Line Size Compatibility: 2" to 24" [51 mm to 610 mm]
Flow Rate:
ST50: 0.75 to 400 sfps [0.23 to 122 mps]
ST51: 0.3   to 400 sfps [0.08 to 122 mps]
Accuracy: (at calibrated conditions)
Standard: ± 2% reading, ± 0.5% full scale
Optional:  ± 1% reading, ± 0.5% full scale
Temperature Coefficient: (at calibrated conditions)
     With optional extended temperature compensation. Valid from 10% to 100% of full-scale calibration
     Flow: Maximum ± 0.025% of reading/ºF up to 250ºF [±0.05% of reading/ºC up to 121 ºC]
Repeatability: 0.5% reading
Temperature Compensation:
Standard: 40 to 100 F [4 to 38 C];
Optional:  0 to 250 F [-18 to 121 C]
Turndown Ratio: 10:1 to 100:1


Flow Element

Installation: Insertion
Type: Thermal Dispersion
Material of Construction: 316 stainless steel body with Hastelloy C thermowell sensors, 316 stainless steel compression fitting with teflon or stainless steel ferrule.
Pressure (Maximum Operating without Damage):
Stainless steel ferrule: 500 psig [34 bar(g)]
 Teflon ferrule: 150 psig [10 bar(g)]
Operating Temperature:
Stainless steel ferrule: 0 to 250 F [-18 to 121 C]
Teflon ferrule: 0 to 200 F [-18 to 93 C]
Process Connection: 1/2" MNPT or 3/4" MNPT with stainless steel or Teflon ferrule.
Insertion Length (Field Adjustable) 1:
1 to 6 inches [25 to 152 mm]
1 to 12 inches [25 to 305 mm]
1 to 18 inches [25 to 457 mm]

Flow Transmitter

Enclosure: NEMA4X (IP67) aluminum, Epoxy coated
Operating Temperature: 0 to 140 F [-18 to 60 C]
Input Power:
DC:18 to 36 Vdc
AC:85 to 265 Vac (CE Mark Approval from 100 to 240 Vac).
Communication Port: RS-232C, Wireless IR to PDA with optional digital display models
Installation: Integral or Remote (50'[15m] max.)

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