The term UHV (ultrahigh vacuum) denotes the pressure range < 10-7 mbar. In order to attain and maintain such low pressures, the degassing rate of the entire apparatus must be extremely low. This can only be achieved by UHV capable materials and degassing of the entire apparatus over a longer period of time at temperatures of about 300 °C. If the ultimate pressure provided by the vacuum pump used is sufficiently low, the ultimate pressure attained in the vacuum system depends on the desorption rate of the chamber walls.
For the reasons outlined above Trinos Vakuum-Systeme GmbH uses exclusively high quality steel materials complying with standard 1.4306 (304L). All components are welded from the inside in line with vacuum requirements or if the geometry does not permit, the components are welded through so as to avoid virtual leaks like cracks and pocket holes. Professional surface processing and cleaning guarantees very low degassing rates. Helium leak test with leak rates below 10-10 mbar × l/s are standard.
Our UHV components are manufactured in accordance with ISO 3669 and Pneurop 6606 standards and in standard sizes of DN 16 to DN 250.
It is important that during the assembly process the bolts on a CF joint are tightened evenly and crosswise so as to avoid any kind of bracing or warping. A radial recess at the flange serves, on the one hand to loosen the flange joint, and on the other hand helps to detect leaks since the helium test gas can be sprayed straight at the sealing surface. With components having two or more flanges, at least one of the flanges should be rotatable so that the components can be aligned as desired.
CF flanges are built for American and International applications, the difference being:
Tube diameter ( inch tubing in the US, metric tubing internationally )
Thread style ( metric for International, and UNC for American applications )
The following table shows all CF flanges built to the US standards. All dimensions are in inch.
Flange
DIN Equivalent
Outer diameter
Thickness
Bolt to Bolt Centerline
Number of holes
Hole Diameter
Thread
Standard Tube Size
1 1/3
16 mm
1.33
0.3
1.062
6
0.172
8-32
0.75"
2 1/8
25 mm
2.125
0.469
1.625
4
0.265
1/4-28
1"
2 3/4
40 mm
2.73
0.5
2.312
6
0.265
1/4-28
1 1/2"
3 3/8
50 mm
3.36
0.687
2.85
8
0.332
5/16-24
2"
4 1/2
63 mm
4.47
0.687
3.628
8
0.332
5/16-24
2 1/2"
4 5/8
80 mm
4.61
0.812
4.03
10
0.332
5/16-24
3"
6
100 mm
5.97
0.781
5.128
16
0.332
5/16-24
4"
6 3/4
130 mm
6.73
0.844
5.969
18
0.332
5/16-24
5"
8
160 mm
7.97
0.875
7.128
20
0.332
5/16-24
6"
10
200 mm
9.97
0.968
9.128
24
0.332
5/16-24
8"
12
250 mm
12
1.125
11.181
32
0.332
5/16-24
10"
For Metric Flanges the sizes are essentially the same, yet they have different tube sizes and metric threads when the holes are threaded.
The following table shows all above dimensions in [mm] and the metric tubes and threads used on these flanges.
