Hand hole

Hand hole refers to the opening structure for people's hands or tools to reach the equipment for installation, overhaul or inspection. It is mainly composed of short pipes, flanges and hand hole covers with handles. The nominal diameter of the common hand hole is 150 ~ 250mm, and the hand hole material has carbon steel and stainless steel. The hand holes are divided into normal and pressurized hand holes according to the pressure condition. They are divided into ordinary and quick open hand holes according to the opening speed. Quick open hand holes are used for regular open field combined with normal pressure, rotary handle and turning cover hole.

The manhole with reduced hand hole is installed to remove, clean and overhaul the internal equipment of the equipment. The structure of the hand hole and the manhole is basically the same, consisting of a short cylinder section and a blind plate. The diameter of the hand hole is usually 150-250 mm, so that workers should wear gloves and grasp the tools of the hand can be easily passed, standardization of the nominal diameter of the hand hole DN150, DN250 two kinds. When the nominal diameter of the equipment is greater than or equal to 1000mm, the manhole should be set.

Mark example

Example: nominal pressure 1.0 MPa, nominal diameter 250 mm, hand hole height 190 mm, type A sealing surface flat cover hand hole, construction drawing number 2, which is marked as

Hand hole A PN1.0, DN250, JB589-79-2