Waterline of the RF flange surface
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I have seen too many RF flange gasket sealing surfaces featuring small, concentric annular grooves – each groove being about 2 mm wide and 1 mm deep, created by using the tip of a cutting tool to make a circle around the surface. Such concentric ring-shaped grooves are often referred to as water lines or water pattern lines. However, such a structural requirement is not specified in the flange standards. What is the difference in pressure resistance and sealing performance between those with and without this water line, and what is the improvement achieved? Please have those with experience in this area reply
The function of the water line on the flange sealing surface is to provide a soft sealing gasket between the two flanges. The gasket can be pressed into the groove. To achieve a better sealing effect.
I agree with what the moderator above said; using things like rubber pads gives better results, while PTFE pads don’t make much of a difference: lol
ASME B16.5 requires this; a water line must be provided. Search for past posts!
I found a post at https://bbs.hcbbs.com/thread-359362-1-1.html; the standards specify a fine helical shape, with certain requirements regarding roughness, and it’s not the common inverted triangular groove
The waterline or water ripple line can achieve a better sealing effect
The standard specifies concentric circles or spirals
Grooved water lines are typically used only on low-pressure flanges; they are more common on flanges that handle water-based media. Flanges used in chemical processing pipelines have fewer water lines, as chemical industry flanges generally use metal wound gaskets or more advanced types of gaskets. If these gaskets are installed eccentrically on flanges with water lines, it can lead to leaks.