A hose pump works by mimicking the action of squeezing a flexible tube, much like squeezing toothpaste from a tube to push it out.
Understanding the Core Principle
As explained in the provided reference, the operation of a hose pump is fundamentally simple: "At home you squeeze it to get the toothpaste. Out and this works exactly the same squeezing to get the liquid. Out this is all that is needed to understand what a hose pump [does]." This analogy highlights the core mechanism: applying external pressure to a flexible hose to push the fluid contained within it.
The Mechanism Behind the Squeeze
Hose pumps, also known as peristaltic pumps, utilize this squeezing action through a rotor with rollers or shoes attached to its periphery.
Here's how it works in detail:
- A flexible hose or tube is fitted inside a circular casing.
- A rotor, typically fitted with two or more rollers or shoes, rotates within this casing.
- As the rotor turns, the rollers or shoes compress or "squeeze" the hose against the casing.
- This squeezing action traps a pocket of fluid between the rollers.
- As the rotor continues to turn, the compressed point moves along the hose, pushing the trapped fluid forward towards the discharge end.
- Behind the roller that just passed, the hose relaxes and returns to its original shape, creating a vacuum that draws more fluid into the hose from the suction end, ready for the next squeeze.
This continuous rotation and squeezing action creates a smooth, positive displacement flow of fluid through the hose. The fluid inside the hose is completely contained and does not come into contact with any mechanical parts of the pump itself, which is a key advantage.
Key Aspects of Operation
- Positive Displacement: Each rotation of the pump displaces a fixed volume of fluid, making them suitable for accurate dosing and metering.
- Gentle Handling: The fluid is moved by being trapped and pushed, without high shear forces, which is ideal for shear-sensitive liquids, slurries, or fluids containing solids.
- Containment: The fluid remains entirely within the hose, preventing contamination of the pump and protecting the pump from corrosive or abrasive fluids.
In essence, the hose pump is a simple yet effective device that leverages the fundamental principle of squeezing a flexible tube to achieve precise and contained fluid transfer.
