FBCNFBOT
FBCN vs FBOT — standardized centrifugal or thermal oil?
Both share the centrifugal principle and back-pull-out construction. The decision point is temperature: up to 260°C FBCN handles it; above 260°C — up to 350°C — FBOT is the path.
TL;DR — Straight answer
FBCN covers industrial processes with clean or turbid liquids up to 260°C and 2,200 m³/h. FBOT is dedicated to organic thermal oils up to 350°C with dual sealing (graphite packing + mechanical seal submerged in bearing oil).
Option A
FBCN
Standardized centrifugal · 260°C
up to 2,200 m³/h
When to use
- Clean or turbid liquids up to 260°C
- Chemical, petrochemical, paper, mining
- Flow up to 2,200 m³/h
- Head up to 135 m
- ASME B73.1
Option B
FBOT
Thermal oil · 350°C
dual sealing
When to use
- Organic thermal oils up to 350°C
- Industrial heating systems
- Pharmaceutical, chemical, food, textile, plastics
- Fluid free of abrasive particles
- Dual-sealing system mandatory
Side by side
| Criterion | FBCN | FBOT |
|---|---|---|
| Primary application | General industrial process | Industrial heating with thermal oil |
| Maximum temperature | 260°C | 350°C |
| Sizes | DN 25 to 300 mm | DN 25 to 300 mm |
| Maximum flow | 2,200 m³/h | 2,200 m³/h |
| Maximum head | 135 m | 135 m |
| Maximum rotation | 3,500 rpm | 3,500 rpm |
| Main standard | ASME B73.1 | ANSI B16.42 150 lbs or DIN EN 1092-2 PN16 flanges |
| Sealing | Packing up to 105°C (12 bar @ 125 lbs) or mechanical seal 90°C, 10 bar | Dual: graphite packings + mechanical seal submerged in oil |
| Construction | Back-pull-out · spiral body with feet | Back-pull-out · spiral body without feet · dual bearing |
| Test pressure | Per ASME B73.1 | 1.5× operating pressure |
Primary application
FBCN
General industrial process
FBOT
Industrial heating with thermal oil
Maximum temperature
FBCN
260°C
FBOT
350°C
Sizes
FBCN
DN 25 to 300 mm
FBOT
DN 25 to 300 mm
Maximum flow
FBCN
2,200 m³/h
FBOT
2,200 m³/h
Maximum head
FBCN
135 m
FBOT
135 m
Maximum rotation
FBCN
3,500 rpm
FBOT
3,500 rpm
Main standard
FBCN
ASME B73.1
FBOT
ANSI B16.42 150 lbs or DIN EN 1092-2 PN16 flanges
Sealing
FBCN
Packing up to 105°C (12 bar @ 125 lbs) or mechanical seal 90°C, 10 bar
FBOT
Dual: graphite packings + mechanical seal submerged in oil
Construction
FBCN
Back-pull-out · spiral body with feet
FBOT
Back-pull-out · spiral body without feet · dual bearing
Test pressure
FBCN
Per ASME B73.1
FBOT
1.5× operating pressure
How to decide in practice
The decisive question is a single one: is the fluid an organic thermal oil in a closed heating loop? If so, the FBOT is the design answer — the series exists precisely for this service, with dual sealing (graphite packing plus a mechanical seal immersed in an oil bath) and continuous operation up to 350 °C. Using a conventional centrifugal at its thermal limit saves at purchase and charges in downtime: the sealing is the first component to suffer.
For the other process liquids — water, condensate, solutions, clean or turbid fluids up to 260 °C — the FBCN is the rational choice: standardized, with 53 models, bench-tested curves and back-pull-out maintenance that frees the rotating assembly without touching the piping. It is the fleet pump, designed for standardization and interchangeability.
In the border zone — thermal oil below 260 °C, intermittent operation — circuit criticality weighs in. A stopped heating system means stopped production: if the pump is the single link between boiler and process, the FBOT dedicated architecture buys reliability exactly where failure costs most.
Frequent technical questions
If process runs at 240°C with thermal oil, which to use?
If the fluid is organic thermal oil, always FBOT — even at 240°C. FBOT's construction is dedicated: dual sealing system maintains bearing thermal stability, and the design without feet avoids differential thermal expansion. FBCN covers 260°C, but for thermal oil FBOT is the correct specification per manual.
Can FBCN handle small particulates?
Yes — FBCN was developed for "clean or turbid liquids" per the manual. For fluids with suspended solids, the manual recommends consulting FB for appropriate sealing chamber specification.
Can FBOT be used for high-temperature water?
Not the recommended application. The FBOT manual literally states: 'The fluid must not contain abrasive particles or materials that chemically attack the pump components.' FBOT was designed for organic thermal oils. For steam or hot water, consult FB — likely FBCN with appropriate sealing chamber.
Are both back-pull-out?
Yes. Both allow removing the rotor+bearing assembly without disconnecting the piping — reduces downtime hours in preventive maintenance.
Still undecided?
The FB application engineer reviews your process condition — fluid, temperature, flow, viscosity — and points to the right series.
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