Technical Overview
The FBCN-50-250 is the FBCN family model with nominal suction diameter DN80 mm and discharge DN50 mm. Standard family version. Part of the 43 standardized pumps of the FBCN series manufactured by FB Bombas in Cabreúva/SP since 1944.
The mid-range of the FBCN series — DN65 and DN80 — handles medium-sized industrial plants and chilled-and-hot water circulation systems. At this scale energy efficiency becomes critical: typical 7.5 to 30 kW motors run continuously, and precise selection of the duty point on the curve determines yearly electrical consumption.
For DN65 and DN80 FB Bombas application engineering typically trims the impeller to bring the duty point closer to BEP — a 3–7% efficiency gain without swapping pumps. The selected bearing group (see model-specific table) defines the heat power that can be continuously dissipated; on viscous or hot-fluid duty a water-jacket cooling on the sealing chamber is commonly specified. ASME B73.1 ensures dimensional interchangeability with equivalent manufacturers — easing retrofit of competitor pumps onto existing baseplates.
Series Operating Range
The FBCN series covers the standard industrial hydraulic envelope for standardized centrifugal pumps per ASME B73.1:
Performance Curves
Q × H hydraulic envelope of the FBCN 50-250 pump at 1750 rpm, extracted from the official FBCN Technical Manual (curve CC-118.07) and bench-validated at FB Bombas test facility in Cabreúva–SP, Brazil.
- Flow range
- 0.5 – 45.0 m³/h
- Head range
- 22.9 – 34.6 m
- Impellers
- 5 × Ø 260–220 mm
- Speed
- 1750 rpm · CC-118.07
Hydraulic envelope — all impellers
Overlaid H × Q curves. Each color represents one impeller diameter.
- Ø 260 mm
- Ø 249 mm
- Ø 239 mm
- Ø 229 mm
- Ø 220 mm
Impeller Ø 260 mm
| Flow · m³/h | 0.5 | 4.2 | 7.8 | 10.6 | 13.3 | 16.0 | 18.7 | 21.7 | 24.5 | 27.0 | 30.4 | 32.7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Head H · m | 34.6 | 34.6 | 34.5 | 34.5 | 34.4 | 34.3 | 34.2 | 34.1 | 33.9 | 33.6 | 33.3 | 33.0 |
Impeller Ø 249 mm
| Flow · m³/h | 1.4 | 5.8 | 9.8 | 13.7 | 17.7 | 21.8 | 25.6 | 29.4 | 33.2 | 37.2 | 41.1 | 45.0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Head H · m | 31.6 | 31.5 | 31.4 | 31.3 | 31.1 | 30.9 | 30.7 | 30.3 | 29.8 | 29.1 | 28.3 | 27.2 |
Impeller Ø 239 mm
| Flow · m³/h | 1.4 | 5.8 | 9.0 | 12.3 | 15.9 | 19.5 | 22.8 | 26.5 | 29.7 | 33.2 | 37.0 | 40.3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Head H · m | 29.1 | 29.0 | 28.9 | 28.8 | 28.6 | 28.4 | 28.1 | 27.7 | 27.2 | 26.6 | 25.9 | 25.1 |
Impeller Ø 229 mm
| Flow · m³/h | 0.8 | 3.4 | 5.9 | 8.3 | 10.3 | 12.5 | 14.9 | 17.3 | 19.4 | 21.6 | 23.8 | 26.1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Head H · m | 26.6 | 26.6 | 26.5 | 26.4 | 26.3 | 26.3 | 26.1 | 26.0 | 25.8 | 25.7 | 25.4 | 25.2 |
Impeller Ø 220 mm
| Flow · m³/h | 4.3 | 6.6 | 8.3 | 10.4 | 12.5 | 14.7 | 16.7 | 18.7 | 20.8 | 22.8 | 24.8 | 26.9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Head H · m | 24.5 | 24.4 | 24.4 | 24.3 | 24.2 | 24.1 | 24.0 | 23.8 | 23.7 | 23.4 | 23.2 | 22.9 |
Mechanical Construction
Pump body (casing)
Corpo de forma espiral, fundido em única peça e apoiado sobre pés próprios. Possui anel de desgaste do lado da sucção.
Impeller
O rotor é tipo radial, de simples sucção, possuindo um anel de desgaste no lado pressão. Exceto para os tamanhos 25-150, 32-125 e 32-125.1.
Shaft and sealing
O eixo é montado com a luva de proteção na região de selagem. Pode ser utilizado gaxetas ou selo mecânico para vedação. Para fluidos com sólidos em suspensão deve ser consultado a FB.
Technical Context: FBCN 50-250 in the Family
The code FB CN 50-250 follows the official FB Bombas naming:
- FB
- — brand
- CN
- — Standardized Centrifugal model
- 50
- mm — nominal discharge flange diameter
- 250
- mm — nominal impeller diameter
Dimensions Table — FBCN 50-250
All dimensions in millimeters, from the official FBCN Technical Manual (page 14). Interpretation per manufacturer dimensional drawing.
FBCN Manual — Figure 7: Dimensional DrawingDimensions referenced in the table below. For other sizes refer to the complete catalog (Table 7, p.14).
| Dim. | Description | Value (mm) |
|---|---|---|
| DN1 | Suction DN | 80 |
| DN2 | Discharge DN | 50 |
| a | Shaft to suction flange distance | 125 |
| f | Total length | 500 |
| h1 | Shaft to base height | 180 |
| h2 | Total height | 225 |
| b | Foot width | 65 |
| g1 | Foot thickness | 18 |
| g2 | Auxiliary foot dimension | 6,35 |
| l1 | Alternative width | 32 |
| m1 | Longitudinal hole distance | 125 |
| m2 | Transverse hole distance | 95 |
| m3 | Foot dimension | 65 |
| n1 | Base length | 320 |
| n2 | Base width | 250 |
| n3 | Additional base distance | 152 |
| n4 | Additional base width | 110 |
| s1 | Main base hole diameter | 14 |
| s2 | Auxiliary base hole diameter | 14 |
| V | Vertical dimension | 130 |
| W | Longitudinal dimension | 370 |
| d1 (m6) | Shaft diameter (ISO m6) | 32 |
| I | Shaft end length | 80 |
| t | Keyway depth | 35,3 |
| u | Key width | 10 |
| x | x dimension | 100 |
Approximate Weight
- Cast iron casing
- 72 kg
- Steel casing
- 75 kg
Bearing Group
- Bearings (2×)
- 6308 C3
- Lubrication
- Oil (gauge/cup)
Sealing Chamber
- Sleeve diameter
- 45 mm
- Chamber diameter
- 64 mm
- Packing
- 3/8"
- Chamber length
- 71 mm
Pressure × Temperature Limits
Maximum discharge pressure limits as a function of pumped fluid temperature, by casing material and flange class (Figures 1–4 of the manual). Effective maximum pressure is always the LOWER between casing pressure and installed flange.
Ferro Fundido
Pressão máxima de recalque (bar) em função da temperatura — Figura 1
- -50 a 120°C20 bar
- 120 a 160°C16 bar
- 160 a 260°C10 bar
Aço Carbono A216 WCB
Pressão máxima de recalque (bar) em função da temperatura — Figura 2
- -50 a 200°C24 bar
- 200 a 260°C16 bar
Aço Inoxidável A743 CF8M
Pressão máxima de recalque (bar) em função da temperatura — Figura 2
- -50 a 200°C16 bar
- 200 a 260°C10 bar
Flanges ANSI B16.1 125 lbs (Ferro Fundido)
Pressão admissível nos flanges em função da temperatura — Figura 3
- -30 a 65°C12,5 bar
- 180 a 260°C5 bar
Flanges ANSI B16.1 250 lbs (Ferro Fundido)
Pressão admissível nos flanges em função da temperatura — Figura 3
- -30 a 65°C25 bar
- 260°C15 bar
Flanges ANSI B16.5 150 lbs WCB
Pressão admissível dos flanges em função da temperatura — Figura 4
- -30 a 65°C16,3 bar
- 180 a 260°C10 bar
Flanges ANSI B16.5 150 lbs CF8M
Pressão admissível dos flanges em função da temperatura — Figura 4
- -30 a 65°C19,5 bar
- 180 a 260°C10 bar
Flanges ANSI B16.5 300 lbs WCB
Pressão admissível dos flanges em função da temperatura — Figura 4
- -30°C51 bar
- 65°C42,5 bar
- 250°C38 bar
Flanges ANSI B16.5 300 lbs CF8M
Pressão admissível dos flanges em função da temperatura — Figura 4
- -30 a 65°C40 bar
- 250°C28 bar
Flanges
→ ANSI B 16.1 125 Lb FF ou 250 Lb FF (ferro fundido)
→ ANSI B 16.5 / 16.42 — 150 Lb RF (aços e ferro nodular)
Peripheral Speed by Material
Casing and impeller material selection determines maximum allowable speed:
- Ferro Fundidoaté 40 m/s
- Ferro Nodularaté 60 m/s
- Aço Carbonoaté 60 m/s
- Aços Inoxidáveisaté 80 m/s
Motor Power Reserve
Recommended safety margins between hydraulic power absorbed by the pump and electric motor power:
- até 2 cvaprox. 20% (mínimo 1,5 cv)
- até 20 cvaprox. 15%
- acima de 20 cvaprox. 10%
Sealing Chamber Options
The FBCN pump can be specified with different sealing chamber configurations depending on pumped fluid nature:
Lubrication by pumped fluid / internal sealing (standard for clean non-aggressive fluids)
External clean liquid sealing (toxic, aggressive, odorous fluids or vacuum suction)
External liquid lubrication and sealing (fluids with solid particles or suspended fibers)
External clean liquid flushing (fluids with abrasive particles or crystallization risk)
Thermal oil application — pure graphite or graphite-carbon fiber packing
Mechanical seals — specified per application need
Applicable Technical Standards
The FBCN line is manufactured in adherence to the following national and international standards:
- ASME B73.1 — mechanical and dimensional standardization of horizontal centrifugal pumps
- API 610 — Petrobras CRCC specification for oil, petrochemical and natural gas applications
- ANSI B16.1 / B16.5 / B16.42 — flange pressure classes
- DIN EN 24250 — component part numbering
Standard Accessories
- Drive
Motor elétrico, motor a diesel, etc.
- Coupling
Acoplamento flexível com ou sem espaçador, padrão FB ou outros fabricantes
- Guard
Protetor padrão FB em aço carbono ou material anti-centelhante
- Base
Base em aço estrutural soldado
Industrial Applications
Typical duty for Medium bore (DN65–DN80)
Characteristic operating window for this class: Typical flow 60–250 m³/h, head 18–110 m.
- Chilled water circulation in industrial chillers
- Mid-size municipal WWTP duty
- Transfer in sugar-and-ethanol refineries
- Industrial irrigation discharge
- Hot water circulation in thermal systems
- Chemical absorption tower feed
Industrial sectors served by the FBCN series
The FBCN pump is recommended for:
Other models with DN80 suction
The models below share the nominal suction diameter DN80 mm and differ by impeller diameter — allowing you to select the appropriate performance curve for your application without modifying the supply piping.
Request Performance Curve and Data Sheet
FB Bombas engineering issues a detailed FBCN 50-250 data sheet with bench-verified performance curve, selected for your operating point (flow × head). Made to order in Cabreúva/SP with documented FAT.
