What effect does the pressure in the jacket have on the insert or its pressure rating?
This question is almost always asked when the jacket pressure exceeds the pressure rating class of the insert assembly. The simple answer is that there isn’t any effect at all. The insert assembly consists of an insert and a flange ring. The flange ring itself does not come into contact with the jacket nor is it’s loading influenced in any way by the jacket or it’s contents. The insert itself, technically, could be considered a closure ring as described by the ASME Boiler & Pressure Vessel Code, Division 1, Appendix 9. The pressure loading would be in the form of a uniform annular ring bound on the O.D. by the jacket pipe I.D. and on the I.D. by the process (core) pipe O.D. This loading would attempt to bend the ring (insert), with the inner and outer edge fixed into a portion of a torus, where the deflection would be axial, toward the gasket side. However, the insert thickness, axial at this section, is usually considerably greater than the annular width. The bending and shear stresse
