External Gear Pump
Definitive guide on external gear pumps — principle, construction, viscosity-based selection, materials, sealing, applications and how to specify. Real data from the FBE technical manual (MTEC-01/01).
DN 1/8" to 6"
Size range
390 m³/h
Maximum flow
350°C
Maximum temperature
100,000 SSU
Maximum viscosity
Quick answer
What is the FBE Series?
The FBE Series is FB Bombas' external gear pump line — the original Brazilian industrial-scale gear pump manufacturer since 1944. Available in DN 1/8" to 6", it covers flows up to 390 m³/h, pressures up to 22 kgf/cm² and temperatures up to 350°C with proper sealing. Compliant with API 676 3rd edition. CRCC Petrobras registered.
How does an external gear pump work?
Two identical helical gears rotate in opposite directions inside the casing. The drive gear is rotated by the shaft; the driven gear rotates by meshing. When teeth disengage on suction side, they create vacuum that draws fluid. Fluid is trapped between teeth and casing, transported around the periphery to the discharge, where teeth re-engage and expel it by positive displacement.
What applications is the FBE suitable for?
The FBE is suitable for viscous fluids from 30 to 100,000 SSU: lubricating and hydraulic oils, asphalt and CAP (with heating chamber), resins and paints, fuels (diesel, biodiesel) with ATEX sealing, vegetable oils and molasses (in sanitary 316 stainless). Brazilian industry standard in asphalt plants, Petrobras BR fuel terminals and chemical processes.
Does the FBE replace Edral, Hidex, Viking, Netzsch, Maag?
Yes. The FBE replaces external gear pumps from any manufacturer — Edral, Hidex, RZR, Viking, Netzsch, Maag, Tuthill — with connection compatibility and custom sizing. Technical manual MTEC-01/01 with official data. In-house manufacturing with documented FAT, original factory spare parts from Cabreúva-SP and direct technical support from our application engineers.
The FBE external gear pump is the most versatile positive displacement pump manufactured in Brazil. It uses external helical gears that capture fluid between the teeth and the casing wall, transporting it with constant volume per rotation. The FB Bombas FBE series covers DN 1/8" to 6", flow up to 390 m³/h, head up to 220 m and operating temperature up to 350°C — for fluids with viscosity from 30 to 100,000 SSU.
What is an external gear pump
An external gear pump is a positive displacement pump that uses two gears with external helical teeth, mounted one over the other — one driving (motor-driven) and one driven (moved by meshing). Body cast in a single piece with integrated feet and ports opposed at 180°.
The pumping principle is volumetric: fluid fills the spaces between teeth and the inner casing wall, transported from suction to discharge with constant volume per rotation. There is no metal-to-metal contact between gears — hydraulic sealing occurs through close-fit proximity. This allows pumping viscous fluids without significant degradation.
How it works — pumping cycle
The external gear pumping cycle happens in four continuous phases:
Phase 1 — Capture
Fluid enters between gear teeth on the suction side. Gear rotation creates partial vacuum that pulls fluid into the chamber.
Phase 2 — Transport
Fluid is captured in spaces between teeth and casing wall. Gears rotate in opposite directions, carrying fluid in "pockets" around each gear.
Phase 3 — Compression
At the meshing zone (where teeth meet), fluid begins to be forced toward the discharge area. The teeth form a seal between suction and discharge.
Phase 4 — Discharge
Fluid is pushed out of the chamber by gear meshing. Discharge is continuous — while gears turn, phases overlap creating constant flow.
FBE anatomy — actual construction
Each component per the technical manual MTEC-01/01:
Pump body— Cast in a single piece with integrated feet for base mounting. Suction and discharge ports opposed at 180°.
Gears— Manufactured with external helical teeth, mounted one over the other — driving gear and driven gear.
Shafts— Two shafts supported on bearings (bushings or rolling bearings per pump size and application). Shaft options: SAE 1045, SAE 8620, SAE 8640.
Bearings— Bushings or rolling bearings specified by size and application. Bushing material: bronze TM 23, graphite or teflon per fluid.
Sealing (front)— Housed in the front region of the pump. Three options: gland packing, type 21 mechanical seal or magnetic coupling.
Suction and discharge ports— FBE 1/8" to 1": internal BSP thread. FBE 1.1/2" to 6": flanges on the casing per ASME B16.1 125 lbs for cast iron.
Operating data — technical envelope
Official data from the FBE technical manual (MTEC-01/01, page 1):
- Sizes
- DN 1/8" to 6"
- Flow
- Up to 390 m³/h (6,500 L/min)
- Head
- Up to 220 m
- Temperature
- Up to 350°C
- Rotation
- 1750 rpm (nominal at 60 Hz)
- Operational viscosity
- 30 to 100,000 SSU
- Maximum suction pressure
- Per model — see selection table
Viscosity-based selection table
Fluid viscosity determines maximum rotation and transmission type. Data from FBE manual Table 2 (page 4):
| SSU | RPM |
|---|---|
| 30 to 250 SSU | 1750 |
| 250 to 2,500 SSU | 1150 |
| 2,500 to 7,500 SSU | 850 |
| 7,500 to 10,000 SSU | 700 to 500 |
| 10,000 to 50,000 SSU | 500 to 300 |
| 50,000 to 100,000 SSU | 300 to 150 |
Source: FBE Technical Manual, Table 2 — Technical data (MTEC-01/01, pg 4). For viscosities above 100,000 SSU, consult application engineering.
Construction materials
The FBE is manufactured in 5 standard materials (manual Table 6, page 6). Selection depends on pumped fluid and chemical compatibility:
- Cast Iron (ASTM A48 CL30)
- Ductile Iron (ASTM A536 60-40-18)
- Carbon Steel (ASTM A216 WCB)
- Stainless Steel (ASTM A743 CF8M (316))
- Bronze (ASTM B584 C93700 (SAE J462 64))
Shafts: SAE 1045 (standard), SAE 8620 or SAE 8640 per application. Gears: SAE 8620 (standard) or SAE 8640.
Sealing options
The FBE offers three sealing options, selected per pumped fluid application (FBE manual, sections 2.4 to 2.7):
Gland packing
Installed in the stuffing box, pressed by a gland follower and adjusted with a hex nut. Industrial standard for general applications.
Mechanical seal type 21
Standard specification: ceramic × graphite × viton, AISI 304 stainless steel spring. For applications requiring leak-tight sealing.
Magnetic coupling
Special sealing for applications where no leakage is acceptable — pumping corrosive, toxic or explosive fluids. Intermediate cup fixed on flange, coupled to pump shaft.
Ports and connections
FBE 1/8" to 1": internal BSP thread on suction and discharge ports. FBE 1.1/2" to 6": flanges integrated in the casing per ASME B16.1 125 lbs for cast iron; for other classes and materials, per material usage and pumped fluid application.
Assembly accessories
- Drive: Electric motor or combustion engine
- Coupling: Flexible with or without spacer, FB standard or other manufacturers
- Coupling guard: FB standard guard in carbon steel or anti-spark material
- Base: Welded structural steel or "U" profile plate
- Nameplate: Aluminum or stainless steel
Industrial applications
The FBE external gear pump is designed to handle viscous fluids in numerous applications, per the official manual:
Chemical— Acids, viscous solvents, resins
Petrochemical— Petroleum derivatives, fuel oils, bitumen
Pulp and paper— Black liquor, starch, glue, pulp
Steel— Rolling oils, cutting fluids
Mining— Hydraulic circuit oils, lubrication
Food— Melted chocolate, molasses, vegetable oils, glycerin
Textile— Dyes, gums, waxes
Pharmaceutical— Viscous bases, syrups, creams
Sanitation— Viscous chemical dosing
Asphalt and bitumen— CAP, asphalt emulsions, polymer-modified asphalt
Nomenclature — how to read the FBE code
The code identifies brand, model, size and construction variant:
FBE 2" CA
FB= Brand (Fabricadora de Bombas)
E= Model: External Gear
2"= Nominal diameter of suction and discharge port (inches)
Sufixos
A— Gear with larger diameter
CA— With Heating Chamber
D— Gear with longer length
DA— Gear with longer length and larger module
M6— Gear with module 6
M8— Gear with module 8
M9— Gear with module 9
M12— Gear with module 12
How to specify — quotation checklist
To size the correct FBE, provide the application engineer with:
- 1Pumped fluid (trade name or composition)
- 2Fluid viscosity at operating temperature (SSU, cP or cSt)
- 3Operating temperature (°C)
- 4Required flow (m³/h or L/min)
- 5Discharge pressure or head (bar or m)
- 6Suction pressure (if available)
- 7Desired material or fluid chemical compatibility
- 8Sealing type (packing, mechanical seal, magnetic coupling)
- 9Drive type (electric motor — voltage/frequency/poles — or combustion)
- 10Optionals: heating chamber (CA), reducer, special base
Standards and certifications
The FBE series is manufactured per API 676 (Positive Displacement Pumps — Rotary) 3rd edition — design, materials, inspection and test requirements for rotary positive displacement pumps. FB Bombas maintains active Petrobras CRCC (Family 6 — Rotating Equipment) for direct supply to the Petrobras chain.
Frequently asked questions
What is the difference between an external gear pump and a centrifugal pump?
External gear is positive displacement — constant volume per rotation, regardless of pressure. Centrifugal is dynamic — flow varies with system resistance. For viscous fluids above ~200 SSU, external gear outperforms centrifugal in efficiency. For low-viscosity liquids at high flow, the centrifugal (FBCN) is more suitable. Full comparison at /en/comparisons/fbe-vs-fbei.
What viscosity range does the FBE handle?
From 30 to 100,000 SSU per manual Table 2 (MTEC-01/01). Rotation is progressively reduced as viscosity increases: 1750 rpm for 30-250 SSU, down to 150 rpm for 50,000-100,000 SSU. For viscosities above 100,000 SSU, consult application engineering.
Which material is best for corrosive fluids?
Stainless Steel ASTM A743 CF8M (316 equivalent) for casing, cover and gears. For extremely corrosive fluids, magnetic coupling eliminates contact-sealing (zero leakage). Consult engineering for specific chemical compatibility.
Can the FBE pump hot asphalt?
Yes. The FBE is one of the most widely used pumps in the Brazilian asphalt industry — operates with CAP (Asphalt Cement), emulsions and polymer-modified asphalt up to 350°C. The CA (With Heating Chamber) version keeps the fluid at the correct temperature during pumping.
How is FBE maintenance performed?
The FBE manual includes cutaway drawing (section 4), parts list with codes (section 4), auxiliary connections (section 5) and dimensional (section 6). Full download at /en/technical-manuals. Spare parts are manufactured in Cabreúva, Brazil — no import dependency.
Does the FBE comply with API for petrochemical projects?
Yes. The FBE series is manufactured per API 676 (Positive Displacement Pumps — Rotary) 3rd edition. FB Bombas maintains active Petrobras CRCC (Family 6 — Rotating Equipment).
Ready to specify your external gear pump?
Send your process data and receive technical sizing from FB's application engineer.
Aplicações industriais
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