The planning commission shall elect annually a chairman from its own members. It shall have power and authority to employ experts, clerks and a secretary, and all expenses incurred by it for such purposes, and all other expenses necessarily and properly incurred by it in the discharge of its duties and in the exercise of its proper functions, but not exceeding in all, the aggregate amount of the annual appropriation and any special or extraordinary appropriations made for its use and purpose, by the council, shall be a charge against the city; and all demands against the city incurred or created by the planning commission, shall before payment, be presented to and approved by the planning commission, and thereafter payment thereof shall be made as provided in Article IX of the Charter. The planning commission shall be deemed to be one of the city departments of the city for all of the purposes and within the meaning of said Article XIII of the Charter. The commissioners will serve without compensation. The planning commission may make such rules and regulations not inconsistent with the Charter or ordinances of the city, as it may deem necessary for its government in the transaction of its business. (Prior code § 7003)