Beneath your feet lies a marvel of engineering the Unterwasser-Pumpe. It stands as a testament to human ingenuity. This isn’t just any pump. The Unterwasser-Pumpe represents a crucial piece of infrastructure.
Let’s step back in time. Imagine a world where water wasn’t as readily accessible as it is today. Cities and towns relied on innovative solutions. They needed to bring water from deep underground to the surface. That is where the Unterwasser-Pumpe became essential.
The inscription on the Unterwasser-Pumpe reads: “zur Förderung von Rohwasser aus 20-60 Meter tiefen Brunnen”. It translates to “for the extraction of raw water from wells 20-60 meters deep”. This reveals the pump’s primary purpose. It was designed to extract raw water. It pulled from deep wells to supply the surrounding area.
The history of such pumps is fascinating. Modern submersible pumps owe their existence to the development of water-filled submersible motors. These are similar to the wet rotor pumps used in heating systems. Friedrich Wilhelm Pleuger invented the water-filled submersible motor in 1928. Pleuger’s Unterwasser-Pumpe was first used during the construction of the Berlin U-Bahn. It helped lower the groundwater level. Pleuger’s company drove many further developments. Today, Unterwasser-Pumpe are often referred to as “Pleuger pumps”.
After World War II, many other manufacturers entered the market. In the 1970s, Pleuger built the world’s largest submersible motor. It had a diameter of 50 inches.
Unterwasser-Pumpe are suitable for various applications. They serve in drinking water supply systems for cities and towns. Dairies, breweries, and mineral water bottlers also use them. These pumps are also utilized in residential water supply systems. Geothermal heat pump systems benefit from them. They are useful for irrigation systems in horticulture, agriculture, and forestry. You can even find them in fountain systems. They can be installed horizontally too. Some use them in pressure boosting systems. Others use them for water management in civil engineering and mining. They are also present in industrial cooling circuits.
These pumps come in various sizes. Manufacturers usually specify the diameter in inches like a 4-inch well pump. The exact diameter can be found in the technical documents. Unterwasser-Pumpe are designed to fit into narrow boreholes. They range from 3 inches for DN80 filter pipes to 10 inches. A unique aspect is their electric motors. These motors are specifically designed for this application. Unlike standard motors, they are slim and cooled by the surrounding groundwater. They are water-filled internally. The motor winding is waterproof. A membrane equalizes the pressure. This allows the Unterwasser-Pumpe to operate at great depths.
Unterwasser-Pumpe are available with different performance characteristics. Some have flow rates of less than one cubic meter per hour. Others manage several thousand cubic meters per hour. Delivery heads range from a few meters to 700 or 800 meters. Unterwasser-Pumpe are made from materials like grey cast iron. Thin-walled stainless steel sheet like 1.4301, 1.4401, or 1.4539 are also used. Thick-walled stainless steel castings or bronze castings are other options. The correct material depends on the quality of the fluid. Motors range from 0.25 kW to 5,000 kW. They support voltages from 220 V to 10,000 V.
An Unterwasser-Pumpe consists of several components. There is the submersible motor at the bottom and the pump hydraulics on top. A non-return valve and a waterproof power cable are included. The electric motor and hydraulic part connect with a flange. They also connect with a shaft coupling. The electric motor drives the shaft of the hydraulic part via the shaft coupling. Impellers are mounted on this shaft.
Between the electric motor and hydraulic part is the pump inlet. This inlet has a strainer. The strainer protects the pump from debris. It prevents stones from entering during operation. Water flows into the pump through the inlet screen. The impellers increase the water pressure. The more impellers, the higher the pressure.
At the head of the pump is the pressure outlet. For 3-inch and 4-inch pumps, this is usually threaded. Larger pumps often have a flange. A non-return valve is installed. It prevents water from flowing back into the well when the pump is idle. This prevents pressure surges.
The Unterwasser-Pumpe before you embodies both history and functionality. It stands as a reminder of the innovative solutions. These solutions provide essential resources.