THE HATCH FOR DUCT MAINTENANCE

摘要

hatches duct maintenance is provided. A lower cover including an engaging opening formed in the duct across the rim of the hatch for maintenance duct in accordance with an embodiment of the present invention ; An upper cover for covering an upper portion of the lower cover ; And through said top cover secured to the lower cover , the height adjusting unit to adjust the height of the upper cover ; And includes a handle, which is fastened to the other parts of the height adjustment . ;