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Model · FBOT · Thermal Oil Pump

Thermal Oil Pump FBOT40-125

Thermal oil centrifugal pump — suction DN65mm, discharge DN40mm, back-pull-out construction.

DN65 × DN40Up to 350°CDownload FBOT Technical Manual
Model
FBOT 40-125
Suction
DN65
Discharge
DN40
Bearing
Mancal 3
Variant: Standard

Operational Limits

Data from Table 1 and Figure 1 of the technical manual

Max Rotation
3500 rpm
Suction Pressure
max 10 bar
Max Temperature
350°C
Hydrostatic Test
1,5 × op.

Maximum discharge pressure × temperature (manual Figure 1)

100°C
~16 bar
200°C
~14 bar
300°C
~11 bar
350°C
~10 bar

Maximum discharge pressure as a function of temperature. Approximate values from Figure 1 of the technical manual. For critical applications, consult FB Bombas engineering.

Technical Dimensions

Dimensions in millimeters per Table 5 of the FBOT Technical Manual

DimensionValue (mm)
DN1 — Suction65
DN2 — Discharge40
a80
f360
h1112
h2140
b50
g115
g26,35
l130
m1100
m270
m365
n1210
n2160
n3160
n4110
s114
s214
V100
W260
d1 m6 (eixo)24
l50
t26,9
u8
x100

Source: Table 5 of the official FBOT Technical Manual — all dimensions in millimeters.

Construction & Components

Official construction data from the technical manual

Back-Pull-Out Construction

Back-pull-out construction — allows bearing frame removal without disconnecting/misaligning piping. Simplifies maintenance.

Pump Body

Spiral-shaped body, cast in single piece without feet.

Impeller

Closed radial impeller, single suction.

Dual Sealing System

Dual safety sealing — graphite packing in first stage (in contact with thermal oil) + oil-submerged mechanical seal inside the bearing frame (ensures thermal stability).

Bearing Frame — Group 3

Configuration2 ball bearings — continuous duty
Bearing sealingShielded, grease-lubricated (low maintenance)
Main lubricationOil (submerged)

Auxiliary Connections

  • D1 — Support drain (¼" BSP)
  • D2 — Mechanical seal leakage indicator (¼" BSP)
  • FF — Oil supply (¼" BSP)
  • V — Vent (¼" BSP)
FB Engineer·Technical perspective on this model

Standard model — default FBOT configuration

This model follows the standard FBOT series construction: single-piece cast spiral body, closed radial single-suction impeller and dual sealing (packing + oil-submerged mechanical seal). Indicated for most thermal oil applications where discharge pressure follows the standard curve of manual Figure 1 (up to 16 bar at 100°C, decreasing to 10 bar at 350°C).

Frequently Asked Questions

Model-specific technical answers based on the official manual

The FBOT 40-125 has suction flange DN65mm and discharge flange DN40mm, per Table 5 of the FBOT Technical Manual. Available flanges: ANSI B16.42 150lbs (standard) or DIN EN 1092-2 PN16 (optional).
The designation follows the FB standard: "FBOT 40-125" where 40 is the discharge flange nominal diameter in mm and 125 is the impeller nominal diameter in mm.
Maximum operating temperature is 350°C per Table 1 of the FBOT Technical Manual. Maximum discharge pressure varies with temperature: approximately 16 bar at 100°C, 14 bar at 200°C, 11 bar at 300°C and 10 bar at 350°C (Figure 1 of the manual). For critical applications consult FB engineering.
The FBOT 40-125 has dual safety sealing: graphite packing (graphite fiber, 5.5mm) in the first stage in contact with thermal oil, and simple mechanical seal (Ø32 or Ø42) oil-submerged inside the bearing frame — ensuring thermal stability of the sealing system.
The FBOT 40-125 uses two ball bearings sized for continuous duty (bearing frame Group 3): the main one runs oil-lubricated — continuous lubrication and thermal stability — and the secondary is shielded, grease-lubricated for low maintenance, per Table 1 of the FBOT Technical Manual.
Yes. All FBOT pumps, including the 40-125, have back-pull-out construction — the bearing frame can be removed from the casing without disconnecting/misaligning the piping. This simplifies assembly, disassembly and maintenance.
Available materials with peripheral speed limits (manual Section 5): Cast Iron up to 40 m/s, Ductile Iron up to 60 m/s, Carbon Steel up to 60 m/s, Stainless Steels up to 80 m/s. The choice depends on thermal oil and temperature conditions. Consult FB engineering for technical recommendation.
The FBOT 40-125 has 4 auxiliary connections of ¼" BSP (manual Table 4): D1 (support drain), D2 (mechanical seal leakage indicator), FF (oil supply) and V (vent). They allow monitoring and maintenance of the sealing system.
Manual Table 2 defines motor power reserve: up to 2cv of required pump power → ~20% (minimum 1.5cv); up to 20cv → ~15%; above 20cv → ~10%. Important to avoid overload operation and extend motor service life.
Clockwise, viewed from the drive end (manual Table 1). Maximum rotation is 3500 rpm. For operation selection at 1750 rpm or 3500 rpm, consult the characteristic curves (manual Section 1). Hydrostatic test is performed at 1.5 × operating pressure.
The FBOT 40-125 is manufactured per ASME B73.1 (mechanical/dimensional standardization of horizontal centrifugal pumps), ANSI B16.42 150lbs flanges in ductile iron (standard) and DIN EN 1092-2 PN16 flanges (optional, European market), with part numbering per DIN EN 24250. Hydraulic acceptance test bench and dynamic balancing per ISO 21940 Grade G2.5. Every pump is approved on FB's hydrostatic test bench (1.5× operating pressure) before shipment.

Application-Specific Sizing

Specific flow rate, head and power depend on the thermal oil, temperature, density, viscosity and available NPSH. Our engineering sizes the ideal FBOT pump using characteristic curves from the technical manual — technical response after analysis.

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All dimensions and construction information were extracted from the official FB Bombas FBOT Technical Manual (MTEC-16/00). Application-specific performance must be consulted with the Engineering Department.