COATED SAND PRODUCTION LINE PAINT-DIPPING AND DRYING PRODUCTION LINE FOR SPRINGS AND CASTINGS INTEGRATIVE RIVET HEATING FURNACE SWING BOLSTER AND SIDE FRAME TURNER FOR TRUCK ROLLER TRACK RISE-AND-FALL TYPE PLAIN BUMPER DENSE PHASE PNEUMATIC TRANSPORT DEVICE FIXED TYPE TWO ARM SELF-HARDENING CONTINUOUS SAND MULLER FIXED TYPE SINGLE ARM SELF-HARDENING CONTINUOUS SAND MULLER MOBILE SELF-HARDENING CONTINUOUS SAND MULLER CENTRIFUGAL TYPE REGENERATING DEVICE