In any municipality operating under Article 6 of this Act, the election polls shall be open at 6:00 a.m., and continued open until 7:00 p.m., of the same day, at which time the polls shall be closed, and no judge shall be behind time for more than 15 minutes after the time for opening such polls. Any judge may absent himself for a reasonable time but only during the casting of ballots, and upon leaving and returning, the judge shall sign a time sheet indicating the period of his absence. When absent for any cause, the judge shall authorize some one of the same political party with himself to act for him until his return.