How to apply for a patent for the same thing

First of all, it should be clear that there are three kinds of patents, namely invention patents, utility model patents and design patents. If you have added a lot of facilities, you can consider applying for invention patents and utility model patents. The former protection period is 20 years, and the latter protection period is 10 year.

If you are improving on the basis of an existing patent, you must get the consent of the existing patentee if you want to implement it after applying for this patent. Similarly, if the former patentee wants to implement your patent, he must also get your consent.

Patents have a time limit, 20 years of invention, utility model and design 10 years. Applying for a patent is public, and anyone in society can consult it. So some better technologies are protected by manufacturers in the form of trade secrets.