PURPOSE: To highten the efficiency of transportation, by integrally providing a cooler and a heater in the halfway part of an introducing pipe connected at one end to the exhaust pipe of an engine and at the other to the discharge section of a granular material tank, to cool and heat exchaust gas at the same time through a compact construction.

CONSTITUTION: An introducing pipe 7 is connected at one end to the discharge section of a granular material tank 2 and at the other to the exhaust pipe 6 of an engine 5. A cooler 20 a heater 31 are provided in the halfway part of the introducing pipe 7. In order to discharge a granular material out of the tank 2, a dump cylinder 3 is first elongated to tilt the tank down. Then, shutoff valves 24, 25 in the introducing pipe 7 are opened and a shutoff valve 23 is closed so that exhaust gas from the engine 5 flows into the discharge section 4 through the exhaust pipe 6, the introducing pipe 7 and a primary air supply pipe 8 to fluidize the granular material to discharge it. At that time, the exhaust gas is simultaneously cooled and heated by the cooler 20 and the heater 31 for drying to smaller weight.