A spiral water pump, also known as a spiral pump or water wheel pump, is a simple, low-lift pump that uses the rotation of a spiral tube wound around a wheel to move water from a source to a slightly higher elevation.
Understanding the Mechanism
This ingenious pump operates based on the principle of trapping alternating volumes of water and air within a coiled tube as the wheel rotates. As these trapped sections are carried upwards and inwards towards the center of the wheel, the air pockets are compressed, which in turn forces the water out through a central pipe.
Step-by-Step Process
Here's a breakdown of how the spiral pump moves water:
- Immersion: The spiral tube is wound around a wheel that is partially submerged in a water source, such as a river or canal. As the wheel rotates, sections of the outer part of the spiral tube dip below the water surface.
- Water Entry: When the inlet surface of the tube (the tube's external extremity) passes into the river, water enters into the tube. Because the tube is angled upwards as it moves towards the center, it also traps a volume of air behind the entering water section before the inlet leaves the water.
- Water & Air Slugs: As the wheel continues to turn, this process repeats, creating a series of alternating "slugs" or sections of water and trapped air within the spiral tube.
- Movement Towards Center: This water volume moves toward the outlet of the tube (the internal extremity), at the center of the wheel.
- Air Compression: As the spiral coil gets closer to the center axle of the wheel, the effective cross-sectional area available for the trapped air within the tube decreases. This reduction in volume compresses the trapped air pockets.
- Forcing Water Out: The pressure built up by the compressed air acts on the water slugs, pushing them ahead towards the outlet.
- Delivery: At the center of the wheel, the spiral tube connects to a straight tube. ...where a straight tube is connected to the end-user. The compressed air pushes the water through this central tube, lifting it to a discharge point.
Key Principles
- Rotation: The rotation of the wheel is the energy source, often powered manually, by animal traction, or even by the current of the water source itself (as a water wheel).
- Alternating Slugs: The key is trapping distinct sections of water and air, preventing the water from simply flowing back out.
- Air Compression: The reduction in volume available for the trapped air as it moves towards the center is what generates the pressure needed to lift the water.
Spiral water pumps are known for their simplicity, reliability, and ability to pump muddy or sandy water without clogging, making them suitable for various low-lift irrigation and water supply applications in rural areas.
