NPS = 2 in E = 3,0625in
D
baut
= 0,625 in A = 6 in
K = 2,38 D
lubang baut
= 0,75 in T = 0,75 in
L = 2,5 in Jumlah lubang baut = 2
R = 3,625 in B = 2,07
9.5. Flange dan Bolting 9.5.1. Flange
Bahan : High Alloy Steel SA 240 Grade O Type 405
Tensile : 60.000 psi
All.Stress : 15.000 psi Tipe
: ring flange
9.5.2. Gasket
- Bahan : asbestos
- m : 2
- minimum design stress : 1600 psi - Tebal gasket
1 pm
y p.m
y di
do +
− −
= Dimana :
y = yield stress = 1600
m = gasket faktor = 2
do = diameter luar gasket di = diameter dalam gasket = diameter luar shell = 168 in
P = internal pressure = 1 atm = 14,7 lbin
2
1 14,72
1600 14,7x2
1600 di
do +
− −
= = 1,0047
do = 1,0047 x di = 1,0047 x 180
= 180,846 in Lebar gasket minimum A =
2 di
do −
= 2
180 180,846
− = 0,423 in
Universitas Sumatera Utara
Diameter rata-rata gasket G = di + A
= 180 + 0,423 = 180,423 in
9.5.3. Baut
- Bahan : High Alloy Steel SA 193 Grade B 8 type 304
- Tensile : 75.000 psi
- All.stress : 15.000 psi
- manentukan jumlah dan ukuran baut Beban gasket Wm
2
= H
y
= π . b . G . y
Dimana : b = lebar efektif gasket
G = diameter rata-rata gasket y
= yield stress b
o
= A2 = 0,423 2
= 0,2115 in ¼ sehingga b
o
= b Wm
2
= π . b . G . y
= 3,14 x 0,2115 x 180,423 x 1600 = 191713,1496 lb
beban agar baut tidak bocor Hp = 2 . b . п . G . m . P
= 2x 0,2115x 3,14 x 180,423 x 2 x14,7 = 7045,4582 lb
beban karena tekanan dalam H = п4 . G
2
. P =
7 ,
14 423
, 180
4 14
. 3
2
x x
= 375639,0998 lb total berat kondisi operasi Wm
1
= H + Hp = 375639,0998 + 7045,4582
= 382684,5581 lb Wm
1
Wm
2
maka yang digunakan untuk mengontrol adalah Wm
1
Perhitungan luas minimum bolting area :
Universitas Sumatera Utara
Am
1
=
2 1
in 25,5123
15000 1
382684,558 fall
Wm =
= Perhitungan bolt optimum
Dari Brownel young, tabel 10.4 hal 188 : Root area
= 2,652 in Bolt spacing = 4 14 in
R = 2 12 in
E = 2
Jumlah baut =
10 9,6
2,652 25,5123
area Root
Am
1
≈ =
=
- Bolting circle diameter C = Di
shell
+ 21,4159 q
o
+ R = 179 + 21,4159 . 316 + 2 12
= 182,0309 in - Diameter luar flange
= C + 2.E = 182,0309 + 2 . 2
= 186,0309 in Cek lebar gasket
Ab
actual
= Jumlah baut x Root area = 10 x 2,652
= 26,52 in
2
Lebar gasket minimum L = Ab
actual
x
G .
y .
π .
2 f
= 26,52 x
180,423 x
1600 x
3,14 x
2 15000
= 0,2194 in L A lebar gasket memenuhi
9.5.4. Perhitungan moment
- Keadaan bolting up tanpa tekanan dalam W
= 2
Ab Am
actual
+ x f
all
= 2
52 ,
26 25,5123
+ x 15000
= 390242,279 lb
Universitas Sumatera Utara
- Jarak radial dari beban gasket yang bereaksi terhadap bolt circle h
G
= ½ C – G = ½ 182,0309 – 180,423
= 0,8093 in - Moment flange
M
G
= h
G
. W =0,8093 x 390242,279 = 313747,4753 lb in - Dalam kondisi operasi
W = Wm
1
= 382684,5581 lb - Gaya hidrostatik pada daerah dalam flange
H
D
= 0,785 x B
2
x P = 0,785 x 180
2
x 14,7 = 373879,8 lb
Brownell Young, hal 242 - Radial bolt circle
h
D
= ½ x C - B = ½ x 182,0309 - 180
= 1,0155 in - Momen komponen
M
D
= H
D
x h
D
= 373879,8 x 1,0155 = 379667,9267 lb in
- Perbedaan antara beban baut flange dengan gaya hidrostatik dalam area flange
H
G
= W – H = 390242,279 – 375639,0998
= 14603,17922 lb M
G
= H
G
x h
G
= 14603,17922 x 0,8093 =11740,6822 lb in - Perbedaan antara gaya hidrostatik total dengan gaya hidrostatik dalam acara
flange H
T
= H - H
D
= 375639,0998– 373879,8 = 1759,2998 lb
Universitas Sumatera Utara
h
T
= ½ x h
D
+ h
G
= ½ x 1,0155 + 0,8093 = 0,9097 in
- Momen komponen M
T
M
T
= H
T
x h
T
= 1759,2998 x 0,9097 = 1600,49 lb in - Momen total pada keadaan operasi
M
o
= M
D
+ M
G
+ M
T
= 379667,9267 + 11740,6822 + 1600,49 = 393009,1 lb in
M
max
= M
o
= 393009,1 lb in
9.5.5. Perhitungan Tebal Flange
