Complete Technical GuideThermal Oil Pump
Complete technical guide on thermal oil pumps: operation up to 350°C, industrial heating systems, material selection and how to specify for your process.
What is a thermal oil pump?
A thermal oil pump is a special centrifugal pump designed to circulate organic thermal fluids in industrial heating systems up to 350°C. It features a mechanical seal immersed in oil with integrated cooling chamber, eliminating the need for external sealing water even at high temperatures. FB Bombas' FBOT Series meets this standard.
Why does a thermal oil pump need a special seal?
At high temperatures (up to 350°C), conventional mechanical seals fail due to thermal expansion, loss of lubrication and elastomer degradation. The FBOT pump uses a special mechanical seal immersed in oil with integrated cooling chamber — the oil itself lubricates and dissipates heat, keeping the sealing element at safe temperature without external water.
What is the FBOT Series temperature range?
The FBOT Series operates at temperatures up to 350°C with special mechanical seal and integrated cooling chamber. Construction in cast iron or carbon steel with oversized bearings for continuous 24/7 operation. Handles flows and pressures compatible with industrial thermal oil systems — boilers, presses, chemical and pharmaceutical processes.
Where are thermal oil pumps used?
Typical applications: thermal oil boilers, industrial presses, pharmaceutical, plastic and chemical processes, textile, pulp and paper, food industry, biodiesel and any plant that depends on reliable thermal fluid circulation at high temperatures. The FBOT Series is manufactured at FB Bombas in Cabreúva-SP since 1944, with documented FAT and direct technical support.
What Is a Thermal Oil Pump?
Centrifugal pump designed for high temperature in heating circuits
A thermal oil pump is a centrifugal pump specifically designed to circulate thermal fluid in industrial heating systems. It operates at temperatures up to 350°C with materials, mechanical seals and bearings sized to withstand thermal expansion, viscosity variation and continuous 24/7 operation.
The FB Bombas FBOT series is designed exclusively for this application: steel construction, mechanical seal with quench/cooling system, bearing cooling chamber and design that accommodates thermal expansion of both fluid and pump. CRCC Petrobras registered, meets API 610 requirements.
Continuous operation up to 350°C
Flow up to 2,200 m³/h, head up to 135 m
Dual sealing: graphite packings + mechanical seal submerged in oil
CRCC Petrobras
How Does a Centrifugal Pump Work?
Kinetic energy to pressure conversion cycle
Axial Suction
Fluid enters through the impeller center (eye) by pressure difference. Rotation creates a low-pressure zone at the center that draws liquid through the suction piping.
Radial Acceleration
Impeller vanes accelerate the fluid radially through centrifugal force. The motor's mechanical energy is transferred to the fluid as kinetic energy (velocity).
Volute Conversion
The high-velocity fluid enters the volute (spiral casing), where the cross-section progressively expands. Deceleration converts kinetic energy into static pressure.
Characteristic Curve
How to read the Q×H chart and find the BEP
Q × H Curve
Relates flow (Q) to head (H). As flow increases, head decreases. Each pump has a unique curve defined by its impeller.
BEP — Best Efficiency Point
Point of maximum efficiency on the curve. Operating near BEP minimizes wear, vibration and energy consumption. The ideal selection point.
Required NPSH
Minimum pressure at suction to avoid cavitation. The available NPSH in the system must always exceed the pump's required NPSH.
Absorbed Power
Energy consumed by the pump at each curve point. Generally increases with flow. Sizes the required electric motor.
Centrifugal Pump Advantages
Why industry chooses centrifugal for high flow rates
High Flow Rates
Capability to move massive fluid volumes. FBCN series handles up to 2,200 m³/h.
Energy Efficiency
High efficiency at operating point (BEP). Lower energy cost per m³ pumped for low-viscosity fluids.
Simple Maintenance
Back pull-out allows removal of rotating assembly without disconnecting piping. Reduces downtime.
Normalized
Standardized dimensions ensure parts interchangeability and easy replacement between manufacturers.
Continuous Flow
No pulsation — smooth, constant flow. Ideal for processes requiring stable line pressure.
Cost-Effective
Lower acquisition and operating cost for low-viscosity applications. Wide parts availability.
Industrial Applications
Sectors that use centrifugal pumps daily
Industrial Water
Intake, distribution and recirculation
Chemical Processes
Solvents, dilute acids and bases
Food & Beverage
Juices, milk, process water
Fire Fighting
NFPA 20 systems, sprinklers, hydrants
HVAC & Building
Air conditioning, cooling towers
Pharmaceutical
Purified water, light solvents
Mining
Drainage, dilute slurry transport
Sugar & Ethanol
Juice, vinasse, boiler water
Centrifugal vs. Gear
When to choose each pumping technology
| Criteria | Centrifugal | Gear |
|---|---|---|
| Ideal viscosity | Low (<100 cP) | High (>100 cP) |
| Max flow | Very high (2,200 m³/h) | Moderate (6,500 L/min) |
| Self-priming | No | Yes |
| Efficiency with water | Excellent | Limited |
| Operating cost | Lower (low visc.) | Lower (high visc.) |
| Best for | Water, solvents, juices | Oils, resins, asphalt |
How to Specify
Essential data for correct sizing
Flow & Head
Desired flow rate (m³/h) and total head (m). Defines the operating point on the Q×H curve.
Fluid Type
Name, viscosity, density, solids concentration and chemical compatibility.
Temperature
Operating and maximum temperature. Defines seal materials and construction type.
Available NPSH
Suction height, piping losses and reservoir pressure. Prevents cavitation.
Installation
Suction and discharge diameters, flange type, available space and base.
Operating Regime
Continuous or intermittent, start frequency, load variation and applicable standards.
Frequently Asked Questions
What is a centrifugal pump?
A centrifugal pump uses the centrifugal force generated by a rotor (impeller) to convert mechanical energy into kinetic and pressure energy, moving low-viscosity fluids such as water, solvents and light chemicals.
How does a centrifugal pump work?
Fluid enters through the rotor center and is radially accelerated by the vanes. High velocity at the rotor exit is converted into pressure by the volute (spiral casing). The pressure difference moves fluid through the system.
What is a centrifugal pump characteristic curve?
It is the graph relating flow (Q) to head (H), efficiency and power. It is essential for selecting the ideal operating point — the BEP — where the pump operates with maximum efficiency and minimum wear.
What fluids are centrifugal pumps suitable for?
Low-viscosity fluids (up to ~100 cP): industrial water, solvents, light chemicals, juices, milk, effluents, cooling water and fire fighting. For viscous fluids, gear pumps are more suitable.
What does normalized centrifugal pump mean?
A normalized pump follows standardized dimensions ensuring interchangeability between manufacturers — same base, flanges and shaft. The FB Bombas FBCN series is horizontally normalized with back pull-out for simplified maintenance without disconnecting piping.
When to choose centrifugal over gear pump?
When the fluid has low viscosity (<100 cP), when you need high flow rates, when pressure is moderate and when operating cost is priority. For viscous fluids or precise dosing, gear is more suitable.
Can I replace my current thermal oil pump with an FBOT?
Yes. The FBOT series replaces thermal oil pumps from any manufacturer — KSB, Schneider, Dancor, Ebara, Sulzer, OMEL, Thebe, Wilo, Famac — with specific design for operation up to 350°C. Mechanical seal with quench, bearing cooling chamber and custom sizing. Brazilian manufacturer since 1944, CRCC Petrobras, API 610.
Companies that Trust FB Bombas
80+ years supplying pumps for industrial heating
Need a thermal oil pump?
Send us your heating system data. Our engineering team will size the ideal FBOT for your operating temperature and flow rate.
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FBCN vs FBOT — standardized centrifugal or thermal oil?
Both share the centrifugal principle and back-pull-out construction. The decision point is temperature: up to 260°C FBCN handles it; above 260°C — up to 350°C — FBOT is the path.
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Which FB pump to use — decision by fluid and condition
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