MKS 253B-1-2CF-1, Instruction Manual

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CF Flange Specifications Appendix A: Product Specifications
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
6 6 6 6 8
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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