Should the protrusion distance of the nozzle on the cover be measured from the original outer surface contour line or from the highest point after the opening is made?
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This post was last edited by zhangjuhua on 2016-10-28 at 12:05. When a hole is made in the head, the top part of it gets pointed; the entire head moves downward at the location of the hole. So, when referring to the extent of the head’s projection, does it refer to the measurement from the original outer surface of the head, or from the highest point after the hole is made? If the pipe is small, the deviation might be only 0–3; if the pipe fitting is larger, the difference could be more than 10, and it becomes quite noticeable when the value is in the tens. If measurements are taken after the hole has been made, it’s difficult to achieve precision unless actual measurements are taken or calculations are done using software – the values are usually decimal numbers. On the other hand, the extension distance is generally an integer, such as 100, making it easier to determine relative to the contour line before the hole was made
It’s not possible to achieve such precise measurement for the extension of the head shell, so its operability is limited
Starting from the highest point after the opening...
First, it’s necessary to determine what purpose this extension distance serves. 1. The projection distance in the nozzle table: If there are multiple openings of different diameters on the cover, they are usually arranged on the same central circle, and it is desired that the flange connection surfaces be in the same plane, with the same projection distance. The external extension distance of the pipe opening at this point refers to the distance from the intersection of the outer surface of the head with the centerline of the pipe opening to the flange connection surface. 2. Calculation of the effective reinforcement height for opening reinforcement: The protrusion distance of the nozzle should be measured from the point where the outer wall of the nozzle meets the outer wall of the head. For illegal takeovers, I think it is advisable to use the average height of the four quadrant points to calculate the effective reinforcement height. 3. The dimension of the pipe extension shown in the assembly drawings, as per NB/T 47042-2014 \"Horizontal Vessels\" Figure 12, the control of the fitting tolerance for the flanges on the head, is based on the tangent line to the head (T.L.). Therefore, the assembly drawing should also indicate the distance from the tangent line of the head to the flange connection surface; the overhang height measured from the outer surface of the head has no direct use in manufacturing and assembly.
This post was last edited by zhangjuhua on 2016-10-28 at 10:44. It seems better to follow the approach suggested in floor 6; reinforcement can be determined by measuring from after the opening is made, while standard markings can be more easily determined based on the outline before the opening is created. The former requires precise measurement or calculation
Well, I also think the 6th floor is good; there’s a lot of text there. . . ;P The optimal floor cannot be set because what you posted is a “discussion thread” rather than a “request for help”. Changing the category to the first level should resolve the issue.