Manhole manufacturer

A manhole refers to an opening structure used for personnel entry and exit for equipment installation, maintenance, and safety inspections. It is mainly composed of short筒节 (or short tube), flanges, and a manhole cover with a handle. In consideration of safety inspections, pressure vessels require a specified number of manholes and their small sizes are detailed in "inspection holes." Manhole materials include carbon steel and stainless steel. Manholes are categorized as atmospheric and pressurized based on pressure conditions; as circular, elliptical, and rectangular based on shape, with rectangular manholes suitable only for atmospheric equipment; and as horizontal and vertical based on installation position. Manhole cover fixing methods include rotating covers and lifting covers; opening speeds of manholes are either standard or quick-open. Manhole structures and dimensions are generally standardized and can be selected or designed according to relevant manuals.