Principle of pumping

When you use a pump, you have to connect its air tube to the valve of the bicycle tire, the role of the valve is to allow only the air from the pump into the tire, do not allow the air from the tire backward into the pump.

The principle of the old-fashioned leather bowl pump: there is a gap between the piston and the wall of the pump, and there is a downward concave rubber bowl on the piston. When the piston is pulled upward, the volume of air below the piston increases and the pressure decreases, so the air above the piston is squeezed from around the rubber bowl to the bottom. Downward pressure on the piston, the volume of air below the piston shrinks, the pressure increases, so that the rubber bowl against the cylinder wall to prevent air leakage to the piston above, continue to press down on the piston, when the air pressure is enough to open the tire valve core, compressed air into the tire. At the same time, the air outside the tube from the upper end of the tube gap into the piston above.

The new sliding barrel pump is the simplest one-way valve. When the outer tube is lifted upward, the air enters the cylinder from the small hole in the sleeve at the lower end of the outer tube, and when the handle is pressed downward, the gas passes through the one-way valve set at the top of the inner tube and enters the inner tube, following the skin tube into the tire valve!

And when the handle is brought up again for the second time, the one-way valve is closed and the air rushes open the one-way valve into the tire when it is pressed down again.

That is, so the process of round-trip cycle back and forth.