Issues with the installation of 8-character blind flanges and bolts
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This post was last edited by jacques0920 on 2019-5-5 12:46. I have two questions for everyone: 1. Can an 8-character blind plate be installed at a 45-degree angle? When is it necessary to install at a 45-degree angle? 2. As shown in the figure below, how should the bolts be arranged when installing the flange? Can bolts be inserted into these four positions? Thank you
For 8-character blind flanges, the bolt holes must match those of the flange bolts (some have only 1 hole, while others have as many bolts as there are flanges). It is installed with flange spans; unlike in your drawings where the bolts are at 0/90/180/360 degrees, they are instead at 45/135/225/315 degrees.
Do you mean whether the holes can still align after being turned 45 degrees? ?
Yes. One is whether it can rotate 45 degrees? Another thing is: when installing the flange, can the bolt holes be arranged according to the layout shown in the diagram?
Could you explain why it needs to be installed at an offset distance? Thank you
I can’t explain it; all the flange installations I’ve dealt with have been like this.
Generally, flanges are installed at the mid-span; one reason is that it’s easier to install the bolts at the bottom, and another reason is that when they are located at the mid-span, the bolts on the sides are less prone to rusting (leaks or rainwater can accumulate below the bolts, and it takes some time before they fall off)
Because both the valves and fittings span the distance.
There is another reason: the flanges of various valves are basically located at the mid-span.
What the expert upstairs said is correct to some extent: the holes should be distributed across the span, not on the center line, and their number must also be a multiple of 4. I’d like to add that for flanges equipped with 8-character blind plates, it’s sufficient to follow the standards; there’s no need to design the size of the holes, the diameter of the hole centers, or the number of holes – these should all be in accordance with the standards. Otherwise, it is a product that does not meet the standards.