Collector with multiple openings
Collector with multiple openings
(OP)
Code: ASME VIII Div.1
I have this collector for a water bath heater. It's a pipe, 8" diameter, with multiple openings aligned and evenly spaced. Above these opening are welded with set-on type a series of pipes, diameter 3", which enter inside the vessel for the coil purpose.
Question: what do I check for reinforcement of these multiple openings?
For UG-40 I check the area of the openings and it doesn't overlap the others. Do I have to check anything else? Because in this case the single openings are exempted according to UG-36(c)(3)(a)(-1), but what about point UG-36(c)(3)(c) and (d)? thanks
I have this collector for a water bath heater. It's a pipe, 8" diameter, with multiple openings aligned and evenly spaced. Above these opening are welded with set-on type a series of pipes, diameter 3", which enter inside the vessel for the coil purpose.
Question: what do I check for reinforcement of these multiple openings?
For UG-40 I check the area of the openings and it doesn't overlap the others. Do I have to check anything else? Because in this case the single openings are exempted according to UG-36(c)(3)(a)(-1), but what about point UG-36(c)(3)(c) and (d)? thanks





RE: Collector with multiple openings
Do you have a sketch you can share, showing arrangement, spacing and thicknesses of pipes?
Design pressure, temperature & corrosión, and materials as well.
Regards.
RE: Collector with multiple openings
Sorry, I can't.
The only image I can show you is this:
RE: Collector with multiple openings
And with reference to the drawing; dimensions and spacing of the openings? Kinda hard based on little info.
RE: Collector with multiple openings
RE: Collector with multiple openings
No design data, no details. Hard to provide specific recommendations. Also you mention that you calculate the areas and there is no overlap. The overlap shall be checked using "d" or "Rn+tn+t" use the larger value.
It is my opinion that you shall do the following:
1) Thickness of header (or collector) shall be calculated per UG-27(c)(1) or App. 1-1(a)(1) using ligaments. Thickness of 3" pipes shall be calculated per same paragraphs but no ligaments.
2) Check limitations listed in UG-36(c)(3)(c) and (d).
3) Check fillet welds per UW-16
4) Check 3" pipes thickness per UG-45, see interpretation VIII-1-15-10
5) Calculate reinforcement as needed. If there is overlap then you shall follow UG-42 rules.
6) Check if App. 1-7(a) applies.
Hope this helps.
RE: Collector with multiple openings
2) Every single hole in the collector is exempted acc. to point (-a)(-1), because the hole is about D.65mm (I take the inside diameter, which is the "real" hole in the collector) with a required min. thk of the collector wall of 9mm. Next step is checking point (-c). The sum of the diameters of 2 openings (130mm) is less than the distance between the centers, so it's ok.
Then point (-d). In this case, the holes are all aligned, so cos (angle)=1, so distance between center must be more than 2,5*(sum of diameter). In my case it's less, so I need a reinforcement. Is it correct?
3)Ok, passed
4)Ok, passed
5) No overlap. Now how could I check the reinforcement? Is stil necessary even if the openings have "walls" (the pipes to coil)?
6)Not applicable
thank you
RE: Collector with multiple openings
Use current geometry as you have, "d", thicknesses for 3" pipe, collector diameter and thickness, materials, etc. and check if opening is properly reinforced. If it is properly reinforced then you are done, if not then you will need to increase thickness of 3" pipe or collector.
Regards.
RE: Collector with multiple openings
RE: Collector with multiple openings
A1+A2+A43 must be >= A, otherwise higher thicknesses are required.
Regards.
RE: Collector with multiple openings
yes, thank you!