Manhole flanges are installed with a variety of stainless steel pouring at the top, as the staff to install, repair, cleaning and maintenance of access channels and vents! General stainless steel manhole, use 304 and 316, two kinds of material steel plate as raw material to make, also can according to customer's request make. The manhole shall be located near the right side of the inlet and outlet pipe and try to make the manhole close to the tank room for personnel access, maintenance of tanks and ventilation connections. Leakage is particularly important because manholes are installed on the lower body ring of the tank. Requirements two flange joint surface must ensure flatness, no floating torsion phenomenon. The stiffeners and flanges shall be cut as far as possible on the entire steel plate without stitching. There shall be sealing rings on the flanges and cover plates, and special attention shall be paid to the protection during construction. 3mm thick asbestos rubber gasket for sealing shall not be allowed to break. Install the manhole cover bolt, diagonally and force, to prevent deformation of manhole cover