As others have stated here, it is normal that equipment obtained through third-party funding stays with the university (in fact, the same applies to salaries which have not been used up). As researcher (Ph.D student or postdoc) you are not an independent legal entity. That's why grant proposal are usally signed by a faculty member, who legally acts on behalf of the university. Of course, this feels unfair when you did all the work and are proud of your success, but the legal situation is usually pretty unambiguous. That being said, as others have stated, simply read through the paperwork concerning the funding. It should become clear quickly who the contractual partner of the funding agency / company was from the legal point of view.
In fact, I knew an assistant professor who moved to a different university and wanted to quietly take "his" computer lab equipment along, for which he had acquired the funding. Result: the dean called him to his office and threatened to call police. A lot of bad blood was generated that day.