PG-32 example
PG-32 example
(OP)
Mínimo diámetro para el cálculo de compensación:
P D
K= ------------ P = 49.5 Kg/cm2 S = 1800 Kg/cm2
1.82 S t D = 1300 mm t = 30 mm
K = 0.6547
D * t = 39000 mm2
(FIG PG-32) dmax = 8.08 (D t (1-K)) ⅓ = 192.2 mm
d < 1/4 Di(shell) = 310 mm
< mayor of: 60 mm and the value obtain from FIG PG-32 = 192.2mm
Then no calculation need be made to determine the availability of compensation for a single opening under 192.2mm. Is it ok?
But if I change the pressure to 48.5 Kg/cm2:
K= 0.9786
dmax= 76.06 mm ---> it's a big difference!
--------------------------------------------------------
Also, with P = 49.5Kg/cm2 and a nozzle of 8" sch 120 ( 219.1 x 18.26 )
PG 32.3.2
D = 1300 < 1500
(d = 219.1) < (D/2= 650) --> 8" ≤ 20" → OK
FIG PG-32: (219.1 – 18.26*2) = 182.58 < 192.2
Then it is no need to calculate the reinforcement.
But:
A = 5758 mm2
A1 = 464.5 mm2
A2 = 2071.5 mm2
A3 = 1095.6 mm2
A1+A2+A3 = 3631.6 mm2 < A = 5758 !! Then it need reinforcement!!
Is it correct? why it is no need of reinforcement calculation when it realy needs?
Any comments should be helpfull
Thanks.
P D
K= ------------ P = 49.5 Kg/cm2 S = 1800 Kg/cm2
1.82 S t D = 1300 mm t = 30 mm
K = 0.6547
D * t = 39000 mm2
(FIG PG-32) dmax = 8.08 (D t (1-K)) ⅓ = 192.2 mm
d < 1/4 Di(shell) = 310 mm
< mayor of: 60 mm and the value obtain from FIG PG-32 = 192.2mm
Then no calculation need be made to determine the availability of compensation for a single opening under 192.2mm. Is it ok?
But if I change the pressure to 48.5 Kg/cm2:
K= 0.9786
dmax= 76.06 mm ---> it's a big difference!
--------------------------------------------------------
Also, with P = 49.5Kg/cm2 and a nozzle of 8" sch 120 ( 219.1 x 18.26 )
PG 32.3.2
D = 1300 < 1500
(d = 219.1) < (D/2= 650) --> 8" ≤ 20" → OK
FIG PG-32: (219.1 – 18.26*2) = 182.58 < 192.2
Then it is no need to calculate the reinforcement.
But:
A = 5758 mm2
A1 = 464.5 mm2
A2 = 2071.5 mm2
A3 = 1095.6 mm2
A1+A2+A3 = 3631.6 mm2 < A = 5758 !! Then it need reinforcement!!
Is it correct? why it is no need of reinforcement calculation when it realy needs?
Any comments should be helpfull
Thanks.





RE: PG-32 example
The question is: how comes that you calculate K=0.65 with P=49.5 kg/cm² and K=0.98 with P=48.5 kg/cm² ?
Also consider that you can't change or determine independently the maximum allowable working pressure, as this will be the consequence of the other data: S, D and t.
prex
http://www.xcalcs.com : Online engineering calculations
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RE: PG-32 example
Now what I realy want to know is why a 8" nozzle is no need to calculate the reinforcement when it realy needs to be reinforced?
Thanks prex
RE: PG-32 example
prex
http://www.xcalcs.com : Online engineering calculations
http://www.megamag.it : Magnetic brakes for fun rides
http://www.levitans.com : Air bearing pads
RE: PG-32 example
something you are doing wrong,
less pressure smaller the k value if 49.5kg k =.6547
if pressure is less the k should be .55 or less
if within limits (on the table/chart)no calculations for compensation are required but do not confuse compensation with reinforcing. you will still need to calculate your welds strengths
genrlblr
RE: PG-32 example
RE: PG-32 example
RE: PG-32 example
RE: PG-32 example
However, if you connect the opening with a nozzle, then additional factors have to be considered, including the stress due to welding, external nozzle loads, etc, which will adversely affect the strength of this joint. That's when you are evaluating the available strength and compare it with the minimum required strength of the joint. If needed, you can add more reinforcement to the joint, in various methods described in the Pressure Vessel code.
Cheers,
gr2vessels