1. Translucent visual inspection function: A tempered glass or acrylic window is embedded in the center of the cover, providing ≥85% light transmittance for clear viewing of liquid level, foam, scaling, and internal component conditions.
2. Personnel access function: Retains standard manhole dimensions (e.g., DN500, DN600), allowing personnel wearing respirators to enter the tank for maintenance and cleaning.
3. High-strength safety glass: The window is made of tempered or laminated safety glass, resistant to impact and temperature changes; if broken, it shatters into blunt fragments, reducing injury risk.
4. Reliable sealing with leak prevention: The cover and flange sealing surfaces are equipped with oil-resistant rubber (NBR), fluororubber (FKM), or PTFE gaskets, achieving zero leakage when closed.
5. Optional explosion-proof protection: An outer stainless steel protective mesh can be added to prevent glass shard projection from external impact, meeting explosion protection requirements for petrochemical tanks.
6. Multiple corrosion-resistant materials: Body and cover available in carbon steel (with anti-corrosion lining), 304/316L stainless steel to suit various media such as oil, chemicals, and wastewater.
7. Labor-saving opening/closing: Hinges and handwheel fastening mechanisms allow one-person operation; optional gas springs or pneumatic struts can be added for assisted lifting.
8. Easy maintenance: The transparent glass and sealing gasket can be replaced on site without disassembling the entire manhole; regular cleaning of the glass surface maintains good light transmission.