The principle of peristaltic pumps and how do they work?

Simply put, it is like pinching a flexible hose with elasticity between your fingers and moving them. As your fingers move, the liquid inside the hose moves along with it. As your fingers push forward, a positive pressure is created at the outlet of the hose, forcing the liquid out. At the same time, a negative pressure is created at the inlet of the hose, drawing in more liquid. This movement of the hose resembles the undulating motion of a peristaltic pump, hence the name "peristaltic pump". The fluid is transported by the positive displacement of the roller pushing the fluid forward, making the peristaltic pump also a positive displacement pump.

In detail:

1. The rotating roller of the peristaltic pump presses down on the flexible hose with elasticity, maintaining sealing at both ends of the pressure point.

2. As the roller rotates, the pressure points on the hose move along with it. Due to the elasticity of the hose, the section of the hose near the inlet naturally springs back as the roller moves away, creating a negative pressure that draws in liquid.

3. With continuous rotation of the peristaltic pump's rotor, the fluid inside the hose continues to be expelled.

Key Points: Elastic hose, sealing at pressure points, positive displacement for fluid discharge.