Which FB pump to use — decision by fluid and condition
Four families, four decisions. Start with fluid, cross through temperature and end on flow. Each answer links directly to the matching series.
TL;DR — Direct answer
If the fluid is organic thermal oil up to 350°C → FBOT. If it's clean or turbid process liquid up to 260°C → FBCN. If it's viscous fluid (oil, asphalt, viscous chemical) with acceptable standard pulsation → FBE. If the same application requires reduced pulsation → FBEI.
Criterion 1: fluid
The first filter is always the fluid
When to use
- Water / liquid process → centrifugal
- Thermal oil → FBOT (dedicated)
- Oil, asphalt, viscous fluids → gear (FBE or FBEI)
- Corrosive viscous chemical → gear with magnetic coupling
Criterion 2: temperature + flow
Second filter tunes the series within the family
When to use
- Up to 260°C + any flow → FBCN
- 260°C to 350°C + thermal oil → FBOT
- Up to 350°C + viscous → FBE
- Up to 232°C with external jacket + low pulsation → FBEI
Quick selection by fluid
| — | Criterion 1: fluid | Criterion 2: temperature + flow |
|---|---|---|
| Clean or turbid water up to 260°C | FBCN (standardized centrifugal) | Flow up to 2,200 m³/h · head up to 135 m |
| Organic thermal oil up to 350°C | FBOT (dedicated to thermal oil) | Mandatory dual sealing · no abrasives |
| Viscous oil or asphalt | FBE (external gear) | 30 to 100,000 SSU · up to 350°C · up to 390 m³/h |
| Process with pulsation-critical downstream | FBEI (internal gear) | Absolute volume control · integrated relief valve |
| Fire protection (NFPA 20 / NBR 10897) | Fire skid (FBCN + jockey + diesel) | Pre-assembled system with automatic panel |
| Application outside the grid | Custom (engineered solutions) | Engineering on demand |
How to decide without doubt
What if the application fits two possible series?
Classic case: viscous process fluid up to 260°C. Could be FBE (positive displacement) or FBCN (centrifugal). The decisive factor is usually specific viscosity: above ~200 SSU the centrifugal loses efficiency and FBE PD wins. Below that, FBCN with proper materials resolves at lower cost.
How to choose between FBE and FBEI?
Both are PD gear pumps. FBE (external) offers a wider size range (1/8" to 6") and temperature (350°C). FBEI (internal) offers reduced pulsation. If the downstream process accepts standard pulsation, FBE. If it requires smooth transfer (precise dosing, reactor injection, volumetric metering), FBEI.
What if I don't know the exact fluid viscosity?
Send what you know — trade name, operating temperature, origin (refinery? process?) — and the application engineer helps estimate. FB manuals have selection tables by viscosity in SSU. For known commercial fluids (Mobiltherm, Therminol, Chevron oils, CAP asphalt), selection is direct.
Can I use the same pump for two different fluids?
Only if both fall within the pump's operating window (temperature, viscosity, chemical compatibility). For two separate applications, two dedicated pumps are usually better — swapping sealing materials due to inter-process leakage typically costs more than an extra pump.
Still unsure?
FB's application engineer evaluates your process conditions — fluid, temperature, flow, viscosity — and points to the right series.
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