Flange connection issues
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The flange interface of the equipment is a flat flange in accordance with the HG/T2105 standard, while the pipe flange I selected is a raised-face flange per standard 20592; these two flanges are fitted together. I have two questions. 1. Can the flanges of these two standards be matched? 2. If a gasket has two different types of sealing surfaces on its sides, will its sealing performance be affected?
The standards are different, making it difficult to align them; it is necessary to check the differences between the two standards.
First, the standards must be unified! Standard specifications include not only dimensional dimensions but also manufacturing and inspection requirements!
This post was last edited by CHANGBAISHI on 2020-9-3 at 15:53. Hehe, this is what you call ‘talking past each other’: lol. A convex flange goes with a concave flange. The gasket is placed on the outer diameter of the convex surface, with the convex part inserted into the concave surface. It is generally used in medium and high-pressure pipelines, valves, and their connection points. The flat flange is equipped with multiple grooves, which, together with the sealing gasket, ensure its stability. The protruding part of a convex flange is flat, and pairing it with a flat flange prevents the flange gasket from being secured properly. It is easy to damage the gasket. If a change is desired, it is recommended to machine the flange in the style of a flat flange; it is also necessary to check whether the hole spacing is suitable, otherwise it will have to be purchased separately.
First, check whether the bolt holes align. As for the flat surfaces and protruding surfaces, shims can be used. https://bbs.hcbbs.com/thread-2955839-1-1.html
He was referring to a convex surface, not a bulging surface
Basically, as long as the diameter and pressure rating are the same for such standards, the number of bolt holes, their size, and the diameter of the central circle will all be identical, so the connection will be fine. The sealing surface has one flat side and one convex side; at low pressures, sealing is not an issue, but at high pressures, leakage is likely to occur. However, it is still recommended not to do this; follow the standard specifications and have the equipment manufacturer supply the flanges directly.
Thank you. Some manufacturers don’t do this; for example, in the case of enamel-lined reactors, they use slip flanges designed for such reactors
When the convex surface is connected to a flat surface, there are no major issues in use for ordinary circulating water or air under normal temperature and pressure conditions. However, the stress varies depending on the forces acting on the flange; if the fluid is flammable or toxic, it is recommended to replace it. Besides, who has ever seen anyone work like this? It’s a joke to others.
Check the bolt hole spacing; pipelines with low pressure can be used for this purpose, and this approach is generally adopted only in emergency situations.