Manhole refers to the opening structure used for personnel to enter and exit equipment for installation, maintenance and safety inspection. It is mainly composed of short tube section (or short tube), flange and manhole cover with handle. For safety inspection considerations, the number of manholes required to be opened for pressure vessels and their minimum dimensions are shown in "Inspection Holes". The manhole materials are carbon steel and stainless steel. Manholes are divided into normal pressure and pressure manholes according to pressure conditions; manholes are divided into circular, elliptical and rectangular manholes according to their shape. Rectangular manholes are only suitable for atmospheric equipment; manholes are divided into horizontal according to the installation position Manholes are installed vertically; the fixing methods of manhole covers include rotating cover and hanging cover; the speed after opening of the manhole has ordinary and quick opening. The structure and size of manholes are generally standardized. Please refer to the relevant manual for selection or design.

Manhole refers to the opening structure used for personnel to enter and exit equipment for installation, maintenance and safety inspection. It is mainly composed of short tube section (or short tube), flange and manhole cover with handle. For safety inspection considerations, the number of manholes required to be opened for pressure vessels and their minimum dimensions are shown in "Inspection Holes". The manhole materials are carbon steel and stainless steel. Manholes are divided into normal pressure and pressure manholes according to pressure conditions; manholes are divided into circular, elliptical and rectangular manholes according to their shape. Rectangular manholes are only suitable for atmospheric equipment; manholes are divided into horizontal according to the installation position Manholes are installed vertically; the fixing methods of manhole covers include rotating cover and hanging cover; the speed after opening of the manhole has ordinary and quick opening. The structure and size of manholes are generally standardized. Please refer to the relevant manual for selection or design.

Manhole refers to the opening structure used for personnel to enter and exit equipment for installation, maintenance and safety inspection. It is mainly composed of short tube section (or short tube), flange and manhole cover with handle. For safety inspection considerations, the number of manholes required to be opened for pressure vessels and their minimum dimensions are shown in "Inspection Holes". The manhole materials are carbon steel and stainless steel. Manholes are divided into normal pressure and pressure manholes according to pressure conditions; manholes are divided into circular, elliptical and rectangular manholes according to their shape. Rectangular manholes are only suitable for atmospheric equipment; manholes are divided into horizontal according to the installation position Manholes are installed vertically; the fixing methods of manhole covers include rotating cover and hanging cover; the speed after opening of the manhole has ordinary and quick opening. The structure and size of manholes are generally standardized. Please refer to the relevant manual for selection or design.