Rotodynamic pumps
The impeller continuously transfers energy to the fluid. Operating flow results from the interaction between the pump curve and the system conditions.
- Technology examples
- Radial centrifugal, mixed-flow and axial-flow pumps.
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Technical guide
Understand operating principles, compare technologies and find out what information to gather before choosing a pump for your process.
Two ways to move a fluid.
Classification starts with the operating principle: rotodynamic pumps and positive displacement pumps. The application comes next.
Centrifugal pumps transfer energy to a liquid through a rotating impeller. Positive displacement pumps transport volumes with each cycle. Gear, screw, piston and diaphragm pumps belong to the second group, with different designs and operating conditions.
Positive displacement
The pump transports volumes through mechanical cycles. Delivered flow also depends on speed, viscosity and internal clearances; it is not independent of operating conditions.
- Technology examples
- Rotary designs such as gear and screw; reciprocating designs such as piston and diaphragm.
What changes with the application
Thermal oil and fire protection describe duties. A thermal oil pump can be centrifugal, as with the FBOT. A fire protection system combines equipment specified for the project; it is not a third pumping principle.
Compare the technology. Then the model.
Each block represents a technology in the FB portfolio. Confirm flow, pressure and temperature ranges in the model documentation and for the specified fluid.
Normalized centrifugal
- Principle
- Rotodynamic
- Construction
- Radial impeller and volute casing
- Fluid
- Clean or turbid liquids; check solids and materials
- What to check
- Curve, suction and viscosity effects
- Documentation
- MTEC-03/00 manual and model curve
External gear
- Principle
- Positive displacement
- Construction
- Two external gears
- Fluid
- Viscous fluids; check operating conditions
- What to check
- Size, speed, viscosity and pressure
- Documentation
- MTEC-01/01 manual and size-specific data
Internal gear
- Principle
- Positive displacement
- Construction
- Rotor and internal gear
- Fluid
- Fluid and viscosity specified for the configuration
- What to check
- Model, speed, suction and service conditions
- Documentation
- MAN001-10 manual and equipment datasheet
Centrifugal for thermal oil
- Principle
- Rotodynamic
- Construction
- Centrifugal assembly for thermal fluid
- Fluid
- Organic thermal oil compatible with the construction
- What to check
- Temperature, fluid, curve and construction limits
- Documentation
- MTEC-16/00 manual and model curve
A family maximum does not define an operating point. Flow, pressure, speed, material and temperature need to be assessed together.
Before choosing, describe the process.
These details support a technical discussion without choosing a series based only on its appearance or connection size.
Fluid and actual conditions
Provide the product, viscosity at operating temperature, density and any solids. A liquid trade name alone does not describe the full duty.
Flow and pressure
State the required flow and pressure or head, including units. If the process varies, provide the known minimum, normal and maximum conditions.
Suction and installation
Describe the tank, pump position and pipework. These details support assessment of pump inlet conditions, head losses and cavitation risk.
Duty and construction
Specify continuous or intermittent operation, the available drive, and material and sealing requirements. Include the datasheet or project specification when available.
Do not have every detail yet? Send what you know and explain your question. A photo of an existing pump nameplate may help locate its documentation.
Explore industrial pump selection criteriaQuestions about pump types.
Answers that distinguish technology, application and equipment selection.
What are the main types of industrial pumps?
By operating principle, the two groups are rotodynamic and positive displacement pumps. Centrifugal pumps belong to the first; gear, screw, piston and diaphragm are examples of the second. Thermal oil and fire protection describe applications, which must be assessed together with construction and service conditions.
What is a centrifugal pump?
It is a rotodynamic pump that transfers energy to a liquid through a rotating impeller. Its operating point depends on the interaction between the pump curve and the system. FBCN is a centrifugal series in the FB portfolio; selection requires the model curve and actual fluid and installation conditions.
What is the difference between centrifugal and gear pumps?
A centrifugal pump continuously adds energy through its impeller; a gear pump transports volumes between its rotating elements. Viscosity affects the two technologies differently. Specify it at operating temperature and assess it with flow, pressure, suction, materials and sealing, rather than using an automatic rule to select a series.
How to choose the right pump type?
Start with the fluid, viscosity and temperature, required flow, pressure or head, suction conditions and operating duty. Compare alternatives against manufacturer documentation and project requirements. To discuss your application with FB Bombas, send the available information and identify what still needs to be defined.
What types of hydraulic pumps exist?
The term hydraulic can refer to liquid transfer or to power transmission circuits. This guide focuses on industrial liquid pumping with rotodynamic and positive displacement technologies. For a hydraulic circuit, confirm the function and conditions required by the equipment; a technology name alone does not establish compatibility.
Explore what your process requires.
Continue with the topic you need: operation, comparison, sealing or installation conditions.
Sources to check the criteria.
General principles from the Hydraulic Institute and documentation published by FB Bombas. Check the revision and configuration applicable to your equipment.
- Hydraulic Institute — Pump System Fundamentals
Operating principles and pump–system interaction.
- Hydraulic Institute — How Viscosity Affects Pumping
Viscosity effects in both pump families.
- Hydraulic Institute — Pump Principles
Radial, mixed-flow and axial-flow pumps.
Hydraulic Institute references are in English. FB documents are available through the manual pages, with their language identified.
Let us understand your application.
Tell us what you need to transfer, the operating conditions and the current difficulty. The conversation starts with your process data.
Explore product seriesTo start the discussion
- Fluid and operating temperature
- Required flow and pressure or head
- New installation or existing equipment