§ 51. Rights of purchasers. The amount paid by a purchaser at such tax
sale, together with the progressive interest or penalties thereon, at
the rate of his bid together with the costs and expenses as herein
provided, shall be due and payable to such purchaser twelve months from
the date of such sale of unimproved or non-residential real estate, and
thirty-six months from the date of such sale of residential real estate,
unless the same becomes due at an earlier date by the service of the
personal notice upon the owner, occupant, mortgagee and other interested
persons, as provided herein.