Pumps are an important tool for conveying fluids, used in many different scenarios and devices. In this article, you will learn exactly where they are used, how they work, what differences exist, and which pump is best suited for pumping out a flooded basement.
Table of Contents
What Is a Pump?
A pump is a turbomachine used to move fluids (liquids or gases) or even sludge from one place to another. It typically converts mechanical or electrical energy into hydraulic energy to convey the fluid, thereby increasing its pressure or achieving a specific delivery head.
What Are Pumps Used For?
| Application Area | Examples of Use |
|---|---|
| Water Management | Drinking water supply, wastewater disposal (sewage treatment plants), irrigation systems |
| Industry & Process Engineering | Transport of chemicals, oils, coolants, dosing of reactants in the chemical and pharmaceutical industries |
| Energy Technology | Circulation of cooling water in power plants, boiler feed, oil pumps |
| Building Services | Heating circulation pumps, pressure boosting systems, drainage of basements and pits |
| Vehicle Technology | Oil, fuel, coolant pumps in engines |
In addition to pure transport, they are also used for circulating liquids in closed systems (e.g., heating circuits) or for mixing liquids.
How Does a Pump Work?
Regardless of the exact type, the function of a pump is based on the principle of supplying energy to the fluid to move it. This happens in two main steps:
- Suction (Suction Side): The pump creates a negative pressure (vacuum) at its inlet. Due to the higher atmospheric pressure outside the pump, the fluid is pushed into the pump.
- Discharge (Pressure Side): The pump exerts a mechanical force on the sucked-in fluid, which increases its velocity and/or pressure. The fluid is forced out through the pump’s outlet.
The way in which the energy transfer takes place differs depending on the pump (see next section).
What Types of Pumps Are There?
They can be primarily divided into two classes that fundamentally differ in their operation: Centrifugal Pumps (dynamic) and Positive Displacement Pumps (hydrostatic):
Centrifugal Pumps (dynamic):
Centrifugal pumps are the most commonly used pumps. They use centrifugal force for energy transfer.
- Operating Principle: A rotating impeller accelerates the fluid radially outwards. The kinetic energy of the fluid is converted into pressure energy in the pump casing.
- Characteristics: Continuous, low-pulsation flow; suitable for large flow rates at moderate pressure
- Subtypes:
- Radial Pumps (e.g., Volute casing pumps): The classic centrifugal pump
- Axial Pumps: Convey the fluid parallel to the pump axis (e.g., for very large volumes at low delivery head)
- Submersible Pumps: A special design that is completely immersed in the medium to be conveyed
Positive Displacement Pumps (hydrostatic):
Positive displacement pumps work by enclosing a specific amount of fluid in a sealed chamber and then mechanically displacing it.
- Operating Principle: They generate a discontinuous flow, but can achieve very high pressure. The flow volume is almost independent of the back pressure.
- Characteristics: Suitable for highly viscous media and applications requiring high pressure and precise dosing
- Subtypes:
- Piston Pumps: Convey by the reciprocating motion of a piston
- Gear Pumps: Convey the fluid in the spaces between intermeshing gears
- Screw Pumps (Progressive cavity pumps): Convey the fluid by the rotation of the screw in a stator
- Diaphragm Pumps: Convey by the deformation of a diaphragm
Which Pump Is Best for Pumping Out the Basement?
For pumping out a flooded basement, submersible pumps are generally the best choice, as they can be placed directly into the water and do not require separate priming. The choice of type depends on the nature of the water:
| Pump Type | Suitable for | Special Features |
|---|---|---|
| Clear Water Submersible Pump | Clean or slightly contaminated water (rainwater, pool water) | Can often pump dry down to a few millimeters (shallow suction) |
| Dirty Water Submersible Pump | Heavily contaminated water (floodwater with sludge, sand, small stones) | Has a larger free passage for solids (particle size often up to 30 mm); this is usually the best choice for a flooded basement. |
| Combined Submersible Pump | Can be switched between clear and dirty water operation | Offers flexibility, but is often expensive; renting a unit may be worthwhile |
Recommendation: For a flooded basement, a dirty water submersible pump is the safest choice, as it can handle the contaminants (sludge, leaves, small stones) that are almost always present in a flooded basement.
Find out how to proceed with drying a flooded basement here.
References:
Prüftechnik. (seen on 10/16/2025). Was ist eine Pumpe? Definition, Beispiele und beste Werkzeuge.
GCEA. (seen on 10/16/2025). Welche Pumpenarten gibt es?
Wassserpumpe.de (seen on 10/16/2025). Flachsauger Tauchpumpe oder Süffelpumpe kaufen.