Fuses are used to protect the wiring - to stop too much current flowing, the wires getting hot, a fire breaking out and the house burning down.
If a device draws too much current the fuse will blow to protect things and people.
Your dryer has an electrical fault that is causing too much current to flow. A dryer will usually have a timer control, a heating element, a fan and a drum turning motor. One of these will probably be defective.
Peccavi
February 2009