| Vacuum Valves - Gate Valves |
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Features:
■ New design and manufacturing process
■ Fewer bearings exposed to vacuum
■ Longer life bearing interface materials
■ Longer cycle life
■ Lowest particulate levels
■ Lower base pressure
■ No virtual leaks
■ Greatly reduced surface areas
■ Fewer parts exposed to vacuum
■ Smaller internal mechanism
■ Weighs less
■ Seals and opens against atmosphere
■ Seals are easily replaced, lower maintenance costs
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Valve Specifications and Construction
All gate, roughing, and bakeable valves have the following standard specifications. Customers may request other material on special order. "Roughing valves" refers to all inline and angle valves. Although they are designed and built for UHV applications, these valves can be used in roughing applications.
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Service Life
■ Up to 100,000 closures with standard bellows seal, dependent on bellows type, poppet seal type, and application
■ Special long life bellows available
■ Up to 500,000 closures with O-ring shaft seal
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Design
No trapped volumes or virtual leaks.
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Valve Construction
Thermionics valve bodies are made of 304 stainless steel. All vacuum-exposed surfaces are 300 series stainless steel. They are engineered, manufactured and internally TIG welded, or 100% full penetration TIG welded, to insure elimination of virtual leaks. Before assembly the valve parts are chemically cleaned and polished.
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Bakeability
Bake-out temperatures are limited by seal material selection, in general:
Buna-N 80°C maximum
Viton 250°C valve open/unloaded; 200°C valve closed/loaded
Kalrez 250°C valve open/unloaded; 150°C valve closed/loaded
All metal 450°C valve open or closed
Solenoids 65°C
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Leak Free
Tested vacuum adverse condition to be leak free with a helium MSLD to a sensitivity of 2 x 10e-10 std cc/sec, no detectable leak.
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Orientation
May be mounted in any position.
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Position Indicators / Limit Switches
Most commonly used with pneumatic valves, designed to show if the seal poppet is in a closed or open position. Thermionics offers both magnetically actuated reed switches and positively actuated microswitches. Both can be provided with lights located either at the valve or at a remote location.
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Flanges
All valves are available with flanges of your choice, be they ConFlat type, ISO, ASA, custom, etc.
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Retention of Gasket in Sealing Poppet
An elastomer gasket seal is held in a double dove-tailed groove to insure retention of the gasket when the vacuum seal is broken. This is particularly important after a bake, when pulling away the seal poppet, or gate, from the sealing surface(seat), or when there is a pressure differential across the seal.
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Choice of Sealing Gasket
Your choice of all metal, Viton, Kalrez, polyimide, and Teflon sealed valves. Viton is the most common sealing gasket material used with the seal poppet or gate. Thermionics offers a wide range of alternative sealing gaskets to users with special bakeout and/or chemical resistance requirements, e.g. copper, Kalrez, polyimide, Teflon, Buna-N, aluminum, gold, etc. Viton is a registered trademark of DuPont Dow Elastomers.
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Construction Materials
| VALVE BODY |
Fabricated from type 304 stainless steel with all internal or back filled full penetration welds using GTAW (known also as TIG) gas welding process. |
| INTERNAL MECHANISMS |
Fabricated from type 304 stainless steel, fully welded GTAW process. |
| CLEANING |
Valves are chemically cleaned for vacuum service. |
| BODY SEAL |
Viton O-ring or OFE copper captured gasket, depending on model. |
| GATE/POPPET SEAL |
Viton O-ring for gate and roughing valves, bakeable valves use an OFE copper gasket. |
| BEARINGS |
Needle and ball bearings, dry film lubricated. |
| BELLOWS SHAFT SEALS |
Fabricated from special application 300 series stainless steels. Roughing and bakeable valves use fully nested, welded bellows assemblies, gate valves may use nested welded or hydroformed bellows, with UHV furnace brazed transition pieces. All bellows have additional convolutions for longer operating life. |
| PNEUMATIC ACTUATORS |
Virgin aluminum cast or drawn. |
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| Vacuum Valves - Butterfly Valves |
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Features
■ 1/4 turn fully open/fully closed
■ Viton O-ring main seal
■ Leak free to 2 x 10e-10 std cc/sec, vacuum adverse
■ 304 stainless steel, vacuum melt bar stock main body
■ Most advanced, patented design
Options
■ Available with alternate elastomer seals
■ Available with O-ring or bellows shaft seals
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| Dimensions given are in inches. |
| Model No. |
Nom. O.D. |
Nom. I.D. |
Flange Type |
A |
B |
C |
D |
| BFV-133 |
1.33 |
0.75 |
ConFlat |
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| BFV-275 |
2.75 |
1.50 |
ConFlat |
4.00 |
2.73 |
1.38 |
1.25 |
| BFV-338 |
3.38 |
2.00 |
ConFlat |
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| BFV-16K |
ISO 16 |
0.75 |
ISO / KF |
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| BFV-25K |
ISO 25 |
1.00 |
ISO / KF |
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| BFV-40K |
ISO 40 |
1.50 |
ISO / KF |
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| BFV-50K |
ISO 50 |
2.00 |
ISO / KF |
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