Hygienic manhole design requirements description

Manholes, also belong to a kind of circular manholes, such as boilers, sewer pipes, and weak electric wells including telecommunications and cable TV. The internal passages for large bridge maintenance are round manholes, usually 600mm in diameter. . It is convenient for workers to enter and exit the tank and ventilate during installation, cleaning and maintenance.
Hygienic stainless steel manholes should be located near the right side of the inlet and outlet pipes, and try to make the manholes close to the tank chambers for personnel access, maintenance of oil tanks and ventilation nozzles.
Since sanitary manholes are installed on the lowermost body ring of the tank, leak prevention is particularly important. It is required that the joint surface of the two flanges must ensure the straightness and no whirling phenomenon. Reinforced plates and flanges should be cut as much as possible on the entire steel plate without splicing. Sealing rings are machined on the flanges and cover plates, so pay special attention to protection during construction.
Sealed with 3mm thick asbestos rubber gasket, no cracking is allowed. When tightening the bolts on the manhole cover, it is necessary to apply diagonal force to prevent deformation of the hole cover.