The F56 metal tube variable-area flowmeter measures instantaneous and totalized flow of liquids, gases, and steam in closed pipelines. A permanent magnet embedded in the float couples non-contact through the measuring tube wall to the indicator, driving a needle display, LCD readout, and/or a two-wire 4-20mA/HART output — no glass, no wetted seals, no process-side electronics.
Non-Contact Magnetic Coupling
The float rides the flow inside a tapered measuring tube. As it settles into equilibrium, the magnetic field it generates is sensed through the tube wall and translated into a flow reading on the indicator dial and, on remote models, into a digital output — with no shaft seals or wetted electrical parts to wear or leak.
Ceramic Gas Damping
Sudden valve openings or pressure surges can make the float bounce or spin, disturbing both the dial reading and the transmitted signal. F56's gas-service models fit a self-centering, jam-proof damper machined from 99.99%-pure aluminum oxide ceramic — corrosion- and wear-resistant, and built to outlast metal alternatives.
Four Indicator Options, One Measuring Tube
Every F56 measuring tube accepts any of four indicator heads, so the same wetted flow path can be specified with local-only display or full remote transmission:
| Indicator |
Display |
Output |
Power |
Best for |
| P8 |
Mechanical needle, polished stainless housing |
None |
None required |
Simple local sight-reading, sanitary areas |
| P10 (Exi / Exd) |
Needle + LCD (instantaneous, totalized, % of scale) |
2-wire 4-20mA / HART; optional KG22 or KG24 alarm switches |
Loop-powered |
DCS/PLC integration, hazardous areas |
| P10I |
Flameproof local needle |
None; optional KG22 or KG23 alarm switches |
None required |
Local reading with switch-point alarming in Ex zones |
| P10B |
Battery LCD (instantaneous + totalized) |
None |
3.6V lithium, ~1-year life |
Sites with no power run to the meter |
Used across oil & gas, chemical, metallurgy, power, food & pharmaceutical, and pulp & paper processes for liquid, gas, and steam flow measurement and process control.
Technical Specifications
| Model |
F56 |
| Media |
Liquid, gas, steam |
| Measuring range (ref. water, 20°C) |
10–300,000 L/h (special ranges on request) |
| Measuring range (ref. air, 0.1013MPa, 20°C) |
0.7–3,000 Nm³/h (special ranges on request) |
| Turndown ratio |
10:1 |
| Accuracy class — local needle |
1.0, 1.5, 2.0, 2.5 |
| Accuracy class — local digital (battery, 1-yr life) |
1.0, 1.5, 2.0, 2.5 |
| Accuracy class — remote (needle + digital) |
1.0, 1.5, 2.0, 2.5 |
| Media temperature — local needle |
-80°C to +300°C (PTFE lining: 0–80°C); high-temp option to 400°C |
| Media temperature — local digital |
-40°C to +120°C (PTFE lining: 0–80°C); high-temp option to 400°C |
| Media temperature — remote |
-40°C to +120°C (PTFE lining: 0–80°C); high-temp option to 400°C |
| Ambient temperature — local needle |
-40°C to +120°C |
| Ambient temperature — local digital / remote |
-20°C to +60°C |
| Media viscosity (excl. F56/SP) |
DN15: <1 mPa·s (F15.00–F15.03), <5 mPa·s (F15.04–F15.30) · DN25: <20 mPa·s · DN50–DN250: <30 mPa·s |
| Nominal pressure — DN15–DN50 |
4.0 MPa (max: DN15/DN25 42 MPa, DN50 32 MPa) |
| Nominal pressure — DN80–DN250 |
1.6 MPa (max: DN80 10 MPa, DN100 6.4 MPa, DN125/DN150 4.0 MPa, DN200/DN250 2.5 MPa) |
| Process connection |
Flange (DIN2501 / ANSI / JIS — DIN recommended); sanitary tri-clamp and threaded available to order |
| Electrical connection |
M20×1.5, 1/2"G, 1/2"NPT, 3/4"G, 3/4"NPT |
| Mounting orientations |
Vertical (bottom-in top-out), horizontal, top-in bottom-out (vertical lines), bottom-in side-out, side-in side-out |
| Straight pipe run |
Inlet ≥5×DN · Outlet ≥250 mm |
| Enclosure rating |
IP67 |
| Explosion-proof rating |
Ex ia IIC T4/T5/T6 Ga (intrinsically safe) · Ex d IIC T6 Gb (flameproof) · Certificate CE16.1206X |
| Intrinsic safety parameters |
Ui=28V, Ii=93mA, Pi=0.65W, Ci≤5nF, Li=0mH (barrier: Uo≤28V, Io≤93mA, Po≤0.65W, Co≥Ci+Ccable, Lo≥Li+Lcable) |
| Output signal |
2-wire (4-20)mA / HART protocol |
Wetted Materials by Series
| Series |
Measuring tube |
Flange |
Float |
| F56/PI, F56/UP, F56/HI, F56/BO, F56/SO |
304/304SS, 304L/304LSS, 316/316SS, 316L/316LSS, 317/317SS, 317L/317LSS |
Same options as tube |
Same options as tube, or Al, Ti |
| F56/SP |
1Cr18Ni9Ti with PTFE lining |
1Cr18Ni9Ti |
PTFE, Hastelloy-B1/B2/C276, Ti |
| F56/PV |
PV |
PV |
PV |
| F56/PP |
PP |
PP |
PP |
| F56/Ni |
Hastelloy-B1/B2/C276, N6 |
Hastelloy-B1/B2/C276, N6 |
Hastelloy-B1/B2/C276, Ti, N6 |
| F56/Ti |
Ti |
Ti |
Ti, Hastelloy-B1/B2/C4 |
| F56/Zr |
Zr |
Zr |
Zr |
| F56/Cu |
— |
— |
Cu |
| F56/Al |
— |
— |
Al |
Flow Range & Pressure Loss by Size
| DN |
Water flow range (L/h) |
Air flow range (Nm³/h) |
Pressure loss (kPa) |
| DN15 |
10–1,000 |
0.30–30.0 |
1.5–3.5 |
| DN20 |
800–2,500 |
24.0–75.0 |
1.5–4.0 |
| DN25 |
1,000–6,000 |
30.0–180.0 |
1.5–16.0 |
| DN32 |
4,000–8,000 |
120.0–240.0 |
8.0–16.0 |
| DN40 |
5,000–10,000 |
150.0–300.0 |
8.0–14.0 |
| DN50 |
6,000–25,000 |
180.0–750.0 |
3.0–16.0 |
| DN65 |
12,000–30,000 |
360.0–900.0 |
6.0–20.0 |
| DN80 |
25,000–65,000 |
750.0–1,950.0 |
14.0–25.0 |
| DN100 |
50,000–100,000 |
1,500.0–3,000.0 |
30.0–40.0 |
| DN125 |
100,000–150,000 |
3,000.0–3,800.0 |
45.0–48.0 |
| DN150 |
125,000–200,000 |
3,800.0–4,500.0* |
45.0–60.0 |
| DN200 |
160,000–250,000 |
Liquid service only in standard range |
60.0–65.0 |
| DN250 |
220,000–300,000 |
Liquid service only in standard range |
60.0–75.0 |
*Air service at DN150 available up to the lower end of the float range only. Ranges above reference clean water at 20°C and air at 20°C/0.1013MPa; finer float-number gradations and special ranges are available — see the full technical datasheet (PDF).