enthalpy, patents are usually published - not granted - after 18 months. There's a big difference. It sometimes takes years after publication before the patent is granted - depending on the patent examiner's questions and how the applicant responds.
Also, there is no requirement to have a prototype, working or otherwise, in order to apply for or be granted a patent.
And remember that being granted a patent does not mean the idea will work or is even physically possible.