What are the main differences in the functions of pressure vessel flanges and pipe flanges?

Take a close look at their sizes first: lol

Pipe flanges are generally used to be welded to pipe ends in order to achieve connection between pipes； A container flange, also known as a equipment flange, is generally a flange used to connect the components of the equipment itself ； Pressure vessel flanges are a type of equipment flange that possess pressure-bearing capabilities. In terms of functional comparison, pipe flanges and equipment flanges differ in terms of the frequency of disassembly and assembly, the stress conditions, and the maintenance requirements during use; this leads to significant differences in their design approaches. Equipment flanges employ a distribution pattern with a large number of smaller bolts, provided that disassembly and assembly are feasible, whereas pipe flanges use a distribution pattern with a smaller number of larger bolts. In this way, under the same operating conditions, the flanges of the equipment can have good stiffness, allowing them to be made small and thin, whereas pipe flanges need to be made large and thick. Therefore, pipe flanges are not suitable for the main body of the equipment (unless the cylinder is made of pipe), and equipment flanges are not suitable for pipes either. (Otherwise, disassembly can be difficult; and if there are any leaks, it’s hard to know which bolts need to be tightened.) For the larger pipe connections on equipment, using equipment flanges is a good option – they are lightweight, provide good stability, and their smaller diameter makes it easier to arrange the surrounding pipes.

Also, generally pipe flanges are smaller than DN600, while equipment flanges are larger than DN600

This post was last edited by Douwan on 2012-3-13 at 14:38. As a supplementary note, device flanges are typically used to connect the cylinder, tube sheets, and other main pressure-bearing components in a device. Generally, flanges on pipes use HGT20592~20615-2009, while flanges on equipment use JB4701~4703. In addition to being used for connecting pipes, elbows, etc., pipe flanges can also be employed on devices with low pressure or small diameters (serving as device flanges, although this is generally not recommended). For example, PN2.5 PL flanges are available with a diameter range of up to DN2000.

Haichuan is a place for improvement; I learned a lot there.

What factors need to be considered regarding stress on equipment flanges and pipe flanges? Could an expert please explain it in detail? I only know about pipe thrust. . .

Haha, I often encounter such problems. It mainly depends on the operating conditions of the equipment and pipelines. When I draw diagrams, I generally prefer to use pipe flanges for diameters below DN600, while for diameters above DN600, pressure vessel flanges are preferred.

The answer from above is absolutely logical; thank you so much. ..........I have learned it.*