Section IV (HW-731.6 Fittings) restricts the attachment of flange-type fittings 3" NPS or less (without additional reinforcement) per figure HW-731 (sketch w-4) to a boiler "wall" thickness of 3/8" or less. Figure HW-731 refers (in title) to "....Connections to Shells, Drums, and Headers"...
Thanks for the reply. ... What limits a design from potential heat stress fractures between tubes. What is the purpose of ligament efficiency per Section IV??
Section IV states maximum pitch dimensions for tube sheets stayed with fire tubes. What calculation determines the minimum ligament distance between tube holes? Are there minimum ligament efficiency percentages that guard against tube holes placed to close to each other.
My calcs from stay area are coming up with 8 stays if using 3/4" diameter stays and 6 with 1" stays, and they are not agreeing with my required diameter calcs?? Something is off; is it possible the calcs are referring to including the staying of the (already) supported edges of the plate?
The...
Using the following calculations based on full pitch dimensions:
Assumed Stay Diameter: 1.50"
Stay Area: 1.767
Pressure (P): 40
Pitch (p): 24
Steel Pressure Rating: 16,000
Stay Load = P x (p2 - a): 22,969
Min. Required Area of Stay = 1.1 * Stay Load/Steel Pressure Rating: 1.579
Required Stay...
According to the ASME Boiler and Pressure Vessel Code: Section IV Article III for Heating Boilers:
HG-342,2 Load Carried by by Stays.
"The area supported by a stay shall be computed on the basis of the full pitch dimensions with a deduction for the area occupied by the stay."
Not sure what...
Is there an appropriate ref. table pertaining to the uses of butt welding boiler pressure vessel parts (shells, chambers, etc.) For example, if the boiler shell is 1/2" thick, when butting two shells together on a girth weld, should the weld be a single bevel groove or a single V groove? Is it...
