MKS 253B-2-2-2 - CF Flange Specifications

CF Flange Specifications A
pp
endix A: Product S
p
ecifications
38
CF Flange Specifications
Valve Type Number 253B-
20-2CF-1
253B-
20-2CF-2
253B-
1-2CF-1
253B-
1-2CF-2
253B-
2-3CF-1
Inside Diameter (A)*
Inches
(mm)
0.779
(19.79)
0.779
(19.79)
1.270
(32.3)
1.270
(32.3)
1.888
(48.0)
Mounting Flange
2¾” CF 2¾” CF 2¾” CF 2¾” CF 3
3
/
8
” CF
Outside Diameter (B)*
Inches
(mm)
2.75
(69.9)
2.75
(69.9)
2.75
(69.9)
2.75
(69.9)
3.25
(82.6)
Controllable
Conductance (l/sec)
min
max
0.07
24
0.25
31
0.20
50
0.40
55
0.35
300
Closed Leakage
(Torr l/sec)
<10
-7
N/A <10
-7
N/A <10
-7
Flapper Seal**
Viton None Viton None Viton
Thickness (C)*
Inches
(mm)
1.25
(31.8)
1.25
(31.8)
1.25
(31.8)
1.25
(31.8)
1.06
(26.9)
Overall Height
Inches
(mm)
8.64
(219.5)
8.64
(219.5)
8.64
(219.5)
8.64
(219.5)
9.14
(232.2)
No. of Bolt Holes
66668
Bolt Hole
Diameter (D)*
Inches
(mm)
0.26
(6.60)
0.26
(6.60)
0.26
(6.60)
0.26
(6.60)
0.33
(8.38)
Bolt Circle Diameter
Inches
(mm)
2.312
(58.7)
2.312
(58.7)
2.312
(58.7)
2.312
(58.7)
2.850
(72.4)
Flange O-ring groove
ID
N/A N/A N/A N/A N/A
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