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Model FBEI

Internal Gear Pump FBEILQ21

Internal gear pump — nominal size 2½" — with integrated relief valve.

Nominal Size: 2½"84 kgDownload FBEI Technical Manual
Model
FBEI LQ21
Nominal Size
2½"
Approximate Weight
84 kg
Manual Reference
Fig. 8
Configuration: With integrated relief valve

Technical Dimensions

Dimensions in millimeters per FBEI Technical Manual — FB Bombas

DimensionValue (mm)
A2½"
B182,6
C260,3
D177,8
E111,3
F101,6
G254,0
H136,7
J13,5
K50,8
L85,9
M231,6
N44,4
O15,7
P15,7
R396,7
S498,3
T57,1
U28,7
W137,9

Source: Official FBEI Technical Manual (Fig. 8) — all dimensions in millimeters. Missing fields do not apply to this configuration.

Construction Features

Per official manufacturer documentation

Operating Principle

Positive displacement — gear within a gear (rotor + idler + crescent)

Sealing Options

  • Mechanical seal (single or cartridge)
  • Braided packing with adjustable gland

Relief Valve

Integrated relief valve with adjustable setting — overpressure protection. Adjustment screw cap oriented toward the suction side.

Heating Jacket (optional)

Steam must not exceed 185°C and/or 10 bar. Thermal fluid limited to 232°C and/or 10 bar (technical manual).

Installation Requirements

Suction filter40–80 mesh
Alignment toleranceradial < 0.05mm · angular < 0.6°
Pre-alignmentYes — performed at factory
Self-primingYes — no foot valve required
ReversibleYes — reversible by rotation direction

Spare Parts (2 years)

  • Internal gear
  • Pin
  • Support and internal gear bushings
  • Sealing kit (packing or mechanical seal + bearing)
FB Engineer·Technical perspective on this configuration

When to choose the with-relief-valve configuration

This configuration is the standard choice for industrial applications where the discharge line may become blocked or closed during operation. The integrated relief valve protects the pump from overpressure without needing an external device in the line — simplifies hydraulic design. Indicated for continuous transfer of viscous fluids in processes where operational safety is critical.

Frequently Asked Questions

Model-specific technical answers based on the official manual

The FBEI LQ21 pump has a nominal size of 2½" on both suction and discharge, according to the official dimensional table in the FBEI Technical Manual (Fig. 8).
The approximate weight of the FBEI LQ21 pump is 84 kg (hydraulic assembly only, excluding motor, coupling and base), per the FBEI Technical Manual. For the total assembly weight including motor and base, contact FB Bombas engineering.
Yes. All pumps in the FBEI series, including the LQ21 model, are self-priming — no foot valve required at the suction point. The technical manual recommends installation as close as possible to the suction source, with a 40-80 mesh filter to prevent cavitation.
Yes. The positive displacement principle (internal gear + crescent) allows bidirectional operation. Simply reverse the motor rotation direction to reverse suction and discharge flow.
The FBEI LQ21 can be supplied with mechanical seal (single or cartridge) or braided packing with adjustable gland. The choice depends on the fluid and operating conditions — consult FB Bombas engineering for technical recommendation.
Yes. The FBEI LQ21 can be supplied with an optional heating jacket for viscous fluids requiring pre-heating. The technical manual defines operating limits: steam up to 185°C and 10 bar, or thermal fluid up to 232°C and 10 bar. The jacket must be heated gradually to prevent thermal shock.
Yes. In the "with integrated relief valve" configuration, the FBEI LQ21 has an integrated relief valve for overpressure protection. The manual specifies that the adjustment screw cap must face the suction side and the opening pressure must be pre-regulated.
The FBEI Technical Manual recommends a 40 to 80 mesh filter (depending on model and application) with passage area equal to or greater than the pump suction nozzle — prevents solid particle ingress and extends internal gear service life.
Radial alignment tolerance is under 0.05 mm and angular tolerance is under 0.6°. FBEI pumps leave the factory pre-aligned, but transport and handling can disturb alignment — re-alignment is mandatory after installation on the final base.
Per Section 3 of the FBEI Technical Manual, recommended parts for 2-year operation are: internal gear, pin, support and internal gear bushings, and sealing kit (packing or mechanical seal + bearing). 2½" sizes are indicated for high-flow transfer of viscous fluids — heavy industrial applications.
The FBEI LQ21 is manufactured per API 676 3rd edition (rotary positive displacement pumps for petroleum, chemical and gas). FB Bombas is a Petrobras CRCC qualified supplier Family 6 — Rotating Equipment, with active corporate registry 61.381.240/0001-78 publicly verifiable at the Brazilian Federal Revenue.

Application-Specific Performance

Flow rate, pressure, speed and power are sized for each specific application (fluid, viscosity, temperature, required pressure and available NPSH). Request free technical sizing — technical response after analysis.

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All dimensions and construction information were extracted from the official FB Bombas FBEI Technical Manual. For customized performance specifications, consult the Technical Assistance Department.