How to understand the height correction value of the high neck flange?

How to understand the height correction value of the high neck flange of the equipment? If the height is increased, the thickness of the small end remains unchanged and then is thinned, or if the corresponding thickness is changed without cutting after the height is increased.
2018-09-17 Reply
The equipment flange NB / T47020 6.5.1 and 6.5.2 states that when the butt cylinder is less than the minimum butt cylinder thickness, the modification, if the modification still conforms to 6.5.1, it needs to be cut.
2018-09-17 08:55:43 Reply