The utility model discloses a just declining / negative pressure sealed enclosure formula air supporting device of sediment machine is scraped in area, including closed air supporting box, characteristics are from left to right separated for the oil trap in proper order, are dissolved air water mixed zone, flotation disengagement zone, are received oil groove and clear water district through the baffle in the box, and the upper portion level in the box is provided with the sediment machine of scraping, dissolve in the air water mixed zone from the top down in proper order the level be provided with and dissolve air water release pipe, intake a water distributor and a sand washing pipe, the lower part is provided with the oily sewage import in the left side of box, and the front side of box is provided with dissolves air water import and first sand washing mouth, and the both sides bottom of box is provided with the drain, the top of flotation disengagement zone transversely is provided with the swash plate, and the below of swash plate has set gradually perforation collector pipe and the 2nd sand washing pipe, and the left side of weir divider intakes part and right side for the clear water and goes out the water part for the clear water in the clear water district, the advantage be can airtight, take and move under negative pressure or the pressure -fired, the quick -witted box formula air supporting device of sediment is scraped in the efficient area of degreasing.