Theophilus van kannel biography for kids

A revolving door is a way to enter or exit a building.

In a revolving door, several panels are fixed on a central axis. The panel can then be rotated to enter or exit the building. Buildings are usually fitted with revolving doors to save energy: Revolving doors can be made to hinder airflow.

Theophilus van kannel biography for kids pictures

This means that less heat is lost. The first to develop revolving doors was H. Bockhacker. In 1881, he registered a patent in Germany for a "door without airflow". Theophilus Van Kannel registered a patent for what he called "storm door", in 1888.

Revolving doors also have problems: Once they start spinning, they force the people to keep a certain walking speed.

Online biography for kids

People who cannot keep up the walking speed may fall and hurt themselves. People in a wheelchair cannot use revolving doors. The same probably applies to blind people. Revolving doors cannot be used in an emerge