Menenetukan Tekanan desain Menentukan Tebal dan Panjang Shell
OD
ID A
B icr
b = tinngi dish
a t
r
OA
sf
C
Gambar C.2.2. Torispherical flanged and dished head. Menghitung tebal head minimum
Menentukan nilai stress intensification untuk torispherical dished head dengan menggunakan persamaan Brownell and Young, 1959:
w =
icr
rc 3
4 1
Brownell and Young,1959.hal.258 Diketahui :
r
c
= 516 in icr = 0,06 x 516 in
= 30,96 in Maka :
w =
96
, 30
516 3
. 4
1
= 1,7706 in
Menentukan tebal head dengan menggunakan persamaan Brownell and Young, 1959,hal. 258:
t
h
= C
0,2P 2fE
.w P.r
c
= 25
, 6990
, 32
2 ,
75 ,
650 .
12 2
7706 ,
1 516
6990 ,
32
= 1,8374 in dipakai plat standar 2,5 in
Untuk t
h
= 2,5 in, Dari Tabel 5.8 Brownell and Young, 1959 diperoleh:
sf = 1,5 – 4,5 in
Direkomendasikan nilai sf = 3 in
Keterangan : t
h
= Tebal head in P = Tekanan desain psi
r
c
= Radius knuckle, in icr = Inside corner radius in
w = stress-intensitication factor E = Effisiensi pengelasan
C = Faktor korosi in Depth of dish b Brownell and Young,1959.hal.87
b =
2 2
2
icr
ID icr
rc rc
=
2 2
96 ,
30 2
516 96
, 30
516 516
= 87,3782 in
Tinggi Head OA OA= th + b + sf
Brownell and Young,1959.hal.87 OA= 1,72 + 87,3782 + 3
= 92,0954 in = 7,6846 ft