There are many duplicate patents. Why? Who is applying for authorization?

You should look at the utility model patent. The patent for utility model is registered at the time of application, and there is no substantive examination period, and there are many repeated applications, but there is an announcement period, that is, the applied patent is announced to the public, and anyone who raises objections will have to reply. So I said, adopt the principle of application priority. When you find that multiple patents overlap, first look at whose patent application comes first, and then who owns the right.