vaccum

The electric fan inside a vacuum cleaner creates a partial vacuum. Atmospheric pressure then pushes the air through the vacuum nozzle due to pressure difference. In short, it is the force due to the atmospheric pressure of air.

Vacuum pumps use a mechanism to repeatedly expand a cavity, allow gases to flow in from the chamber, seal off the cavity, and exhaust it to the atmosphere. Thereby creating an atmospheric pressure gradient letting the objects/gases to rush along with.