Bike air pumps work by creating a pressure difference that forces air into the tire. The pump uses a piston inside a cylinder to reduce the volume, thus increasing air pressure.
Here's a breakdown of the process:
- The Stroke Begins: When you pull the pump handle, the piston inside the cylinder moves, increasing the volume of the cylinder. This increase in volume reduces the air pressure inside the cylinder.
- Air Intake: The pressure inside the cylinder becomes lower than atmospheric pressure. This pressure difference forces air to flow into the cylinder through an intake valve (usually a one-way valve).
- The Pumping Stroke: When you push the handle, the piston moves, decreasing the volume of the cylinder. This decrease in volume compresses the air inside, increasing its pressure.
- Air Transfer: The pressure inside the cylinder now becomes higher than the pressure inside the bicycle tire. This pressure difference forces the air to flow out of the cylinder, through the pump's hose, and into the tire through a one-way valve in the pump head.
- Repeating the Cycle: The process repeats each time you pull and push the handle, gradually increasing the air pressure inside the tire.
In essence, the bike pump's piston mechanism creates a cycle of low pressure (drawing air in) and high pressure (forcing air into the tire). Atmospheric pressure plays a crucial role in pushing air into the cylinder during the intake stroke.
