A franchise granted under this chapter does not become effective until the grantee files written acceptance thereof with the clerk of the granting municipality. When so filed the acceptance constitutes a continuing agreement by the grantee that if and when the granting municipality thereafter annexes, or consolidates with, additional territory, all franchises, rights and privileges owned by the grantee therein, except a franchise derived under Section 19 of Article XI of the Constitution as that section existed prior to the amendment thereof adopted October 10, 1911, shall be deemed abandoned within the limits of the additional territory.