Manhole with neck flat welding flange

Neck welding flange manhole is a commonly used type of manhole, which is a general term for access holes used for boilers, storage tanks, oil tanks, etc. for personnel to enter and exit for maintenance; For the installation, disassembly, cleaning, and maintenance of internal equipment, people can enter and exit storage tanks, boilers, oil storage tanks, etc. through this hole. It is usually installed on the top of storage tanks and containers, and is used in conjunction with air breathing valves and tank washers. The manhole also plays a role in safety and fire prevention, and is a safety device for protecting storage tanks. It is particularly suitable for storing materials in dome shaped atmospheric pressure tanks capped with nitrogen. Manholes are divided into emergency pressure relief manholes, performance stable fire-resistant breathing manholes, tank top manholes, tank wall manholes, and core manholes; The manhole is located at the bottom of the tank and is subjected to high liquid pressure. In order to prevent leakage, strict requirements must be placed on the installation quality of the manhole. Manholes are divided into emergency pressure relief manholes, performance stable fire-resistant breathing manholes, tank top manholes, tank wall manholes, and core manholes. Manholes are classified according to their appearance: quick opening manholes, circular manholes, square manholes, elliptical manholes, external manholes, and internal manholes

The material of the flange manhole with neck welding can be divided into: carbon steel manhole (carbon steel: 20 #, Q23 excellent, ASTM A234, ASTM A105, etc.); Stainless steel manhole (stainless steel: ASTM A403, 1Cr18Ni9Ti, 0Cr18Ni9, 00Cr19Ni10, 00Cr17Ni14Mo2, 304, 304L, 316, 316L, etc.)

Common manholes include: atmospheric pressure manhole, rotary cover plate flat welding flange manhole, rotary cover with neck flat welding flange manhole, rotary cover with neck butt welding flange manhole, vertical hanging cover plate flat welding flange manhole, vertical hanging cover with neck butt welding flange manhole, vertical hanging cover with neck butt welding flange manhole, horizontal hanging cover plate flat welding flange manhole, horizontal hanging cover with neck flat welding flange manhole, horizontal hanging cover with neck butt welding flange manhole, atmospheric pressure rotary handle quick opening manhole, elliptical rotary cover quick opening manhole, rotary arch cover quick opening manhole, atmospheric pressure handhole, plate flat welding flange handhole, neck flat welding flange handhole, neck butt welding flange handhole, Manhole manufacturing execution standard: HG/T21515-21535-2014