A foldable and positioning device of a scooter controlled by a leg of a driver comprises: a support frame having two positioning plates; a connecting seat positioned at a front end of the scooter body; two pedals; and a spring installed between one post and a rotary shaft. Also, the size of the product is much reduced compared to the case that the electric motor protection relay is connected in parallel, and its cost can be reduced. A control system shuts off the flow of primary air to the coal pulverizer, when the coal pulverizer is being repaired or serviced while the furnace is in operation. The elongate arm is in the form of least one elongate member.