ST98HP Mass Flow Meter

Yellow FCI ST meter with tube tee

Mass Flow Meter Summary

The ST98 High Purity mass flow meters are designed for hygenic gas flow measurement in the pharmaceutical, biotech, food and beverage and semiconductor industries. FCI's thermal dispersion technology provides exceptionally accurate and repeatable direct air/gas mass flow rates. The sensing element combines two matched precision resistance temperature detectors (platinum RTDs). The active RTD is preferentially heated with a constant current. The reference RTD is preferentially heated with a constant current. The reference RTD senses at the process fluid temperature. As flow passes the element a resistance differential is produced proportional to the mass flow rate.


  • High purity gas monitoring
  • Pill coater air flow monitoring
  • CIP and SIP flow and temperature monitoring
  • Condenser/evaporator flow control
  • Scrubber gas discharge monitoring
  • Process flow measurement and monitoring


Flow Range: 2.0  SCFM to 3183 SCFM [3,4 NCMH to 5409 NCMH] in air at standard conditions for 70°F [21,1°C] and 14.7 psia [1,01325 bar(a)], typical to most gases; all gases must be compatible with the flow element material

Accuracy: (at calibrated conditions)
  • Flow: ± 1% reading + 0.5% full scale accuracy (standard)
  • Temperature: ± 2°F [± 1°C] (for display only; flow rate must be grater than 5 AFPS [1,5 AMPS])
  • Temperature Coefficient:

With optional temperature compensation. Valid from 10% to 100% of full-scale calibration
Flow: Maximum ± 0.015% of reading/ºF up to 850ºF [±0.03% of reading/ºC up to 454 ºC]

  • Flow: ± 0.5% reading
  • Temperature: ± 1°F [± 0,6°C] (flow rate must be greater than 5 AFPS [1,5 AMPS])

Turndown Ratio: Factory set and field adjustable from 10:1 to 100:1 within the calibrated flow range.

Temperature Compensation: 
  • Standard: ± 30°F [± -1°C]
  • Optional: ± 100°F [± 38°C]

Agency Approvals:  ASME BPE, Cenelec (T4 Rated), CE Marking per EMC Directive 89/336/EEC; FM. CSA, and CRN pending.
N.I.S.T. Certified Test Lab Calibration: Standard

Flow Element

Materials of Construction: All welded 316L stainless steel
  • ST98 HP: 15 Ra electropolish (standard); 10 Ra electropolish (optional); Hastelloy-C with 15 Ra electropolish (optional)
  • ST98 UP: 10 Ra or 15 Ra electropolish (standard)

Operating Pressure: 0 psig to 250 psig [17 bar(g)]; designed pressure to 1000 psig [69 bar(g)], maximum operating pressure limited by customer specified process connection

Operating Temperature:
Process temperature: -40°F to 350°F [-40°C to 177°C]; integral electronics rated from 0°F to 140 F [-18°C to 60°C]
  • Optional: -100°F to 500°F [-73°C to 260°C]; integral electronics rated to 140°F [60°C]

Flow Element Process Connection:
  • ST98 HP: 1" [25 mm] sanitary flange
  • ST98 UP: 1" [25 mm] VCR connector

Flow Transmitter

Operating Temperature: 0°F to 140°F [-18°C to 60°C]

Input Power: 85 Vac to 265 Vac, 22 Vdc to 30 Vdc; 7 watts maximum, 230 mA maximum

Output Signal:
  • Current: 4-20 mA; 700 ohms maximum load
  • Voltage: 0 Vdc to 10 Vdc, 0 Vdc to 5 Vdc or 1 Vdc to 5 Vdc; 100,000 ohms minimum load

Communication Port: EIA-232 [RS-232] HART and Profibus Communications (optional): Two way.

Optional Display: 2 lines, 16 characters per line. Indicates flow rate and process temperature or totalized flow.

Remote Enclosure (if selected):
  • Standard: NEMA/CSA Type 4 carbon steel, Type 4X aluminum or stainless steel (meets IP66); nonincendive for Class 1, Division 2, Groups A, B, C, D; Suitable for Class II, Division 2, Groups F and G; Class III, Division 2
  • Optional: NEMA/CSA Type 4X aluminum (meets IP66); Nonincendive for Class 1, Division 1, hazardous locations, Group B, C, D, E, F and G; and EEx d llC


  • ATEX
  • CCoE
  • CE
  • CPA
  • CRN
  • CSA
  • FM
  • IECEx
  • HART