Menentukan Rasio H Menentukan Jumlah Courses
t
s
= c
P E
f d
P
d
6 ,
. .
2 .
Brownell Young,1959.hal.254 keterangan :
ts = ketebalan dinding shell, in
Pd = tekanan desain, psi
D = diameter tangki, in
f = nilai tegangan material, psi
Carbon Steel SA-283 Grade C 12.650 psi Tabel 13.1, Brownell Young, 1959:251
E = efisiensi sambungan 0,75
jenis sambungan las single-welded butt joint without backing strip, no radiographed
C = korosi yang diizinkan corrosion allowance
0,25 in20 th Tabel 6, Timmerhaus,1991:542 Menghitung ketebalan shell t
s
pada courses ke-1: t
s
= 9690
, 2
3 6
. -
0,75 x
psi x12.650
2 516
x psi
9690 ,
2 3
in
+ 0,25 in = 1,1484 in 1,15 in
Tabel C.2.6. Ketebalan shell masing-masing courses
Courses H ft
P
desain
psi t
s
in ts
standar
in 1
32,0000 32,9690
1,1450 0,8500
2 24,0000
29,9676 1,0655
0,8000 3
16,0000 26,9663
0,9846 0,7500
4 8,0000
23,9650 0,9027
0,7000
Panjang Shell Untuk menghitung panjang shell, persamaan yang digunakan adalah :
L =
n weld
D
o
12. length
- π.
Brownell and Young,1959 Keterangan :
L = Panjang shell, in
D
o
= Diameter luar shell, in
n = Jumlah plat pada keliling shell
weld length = Banyak plat pada keliling shell dikalikan dengan
banyak sambungan pengelasan vertikal yang diizinkan.
= n x butt welding Menghitung panjang shell L pada courses ke-1 :
t
s
= 0,25 in D
o
= D
i
+ 2.t
s
= 516 + 2 x 0,8500 = 517,7000 in
n = 4 buah
butt welding = 532 in Brownell and Young,1959,hal. 55
weld length = n . butt welding
= 4 . 532 = 0,6250 in
L =
4 x
12 0,6250
- in
517,7000 3,14.
= 30,2461 ft
Tabel C.2.7. Panjang shell masing-masing courses.
Plat ts, in
do in L ft
1 0,8500
517,7000 33,8532
2 0,8000
517,6000 33,8466
3 0,7500
517,5000 33,8401
4 0,7000
517,4000 33,8336