Vacuum Technology and Vacuum Design Handbook for Accelerator ...

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join sections of beam line or equipment that have a deliberate mis-alignment. They can be purchased with almost any style of flange including specials. See example pictures. 9.2 Edge Welded Bellows These bellows are made up from very thin stainless steel discs stacked together and welded along their edges. The advantage of the design is the concertina style bellows that is very flexible allowing designs that have long extensions and short compressions. They have two main applications. Firstly, applications that requires a device to extend or contract into the vacuum space where an elastomeric seal on a sliding shaft is not adequate. Such as a sample manipulator or Faraday cup. Secondly, where a device such as a detector or sample positioner is sensitive to vibration and must be decoupled from the vibration source. 10. Valves Large bellows. ~300mm diameter. Stainless steel, wall thickness ~ 0.8 mm. This bellows is used to correct alignment offsets in the magnet box Medium bellows. ~ 100 mm diameter. Stainless steel, wall thickness
on the location of the valve. See the Accelerator WIKI for values around the ANTARES. Once an interlock has tripped the switch that operates the gate valve is bypassed. To reset the valve: Notes: • The vacuum must be within the high vacuum range as read on the corresponding vacuum gauge controller with a pressure better than the trip point. • Once this level is reached the bypass button is held down momentarily. • At this point the pressure will rise then fall as the gas load is pumped away. • When the system pressure is less than the trip level the bypass switch can be let go. • An indicator light near the switch will show its status. • Operators and technicians must be aware that gate valves must be orientated so that the gate always seals towards the vacuum pump. That is, they seal best in one direction only. Failure to orientate the gate the correct way may cause a vacuum leak when atmospheric pressure forces the gate off its seal. • In some cases gate valves may remain sealed after they have been switched to open. This can be due to the withholding (sometimes called back pressure) pressure not being adequate enough to lift the gate off the seal. • Gate valves, while mostly metal can become hot if a gate is closed in front of an ion beam. If left for long periods with high current beams the elastomer seals may warm up and begin to outgas. • For roughing ports typically 25KF bellows sealed valves are used. On STAR these same valves are used to isolate vacuum gauges for cleaning. • Where fine flow control is required for either roughing out or venting, metering valves are used. These are basically multi-turn needle valves for fine adjustment. • Valves do require maintenance to keep the seals clean and in working order. After long periods of time the ‘o’ ring seals will deform and often will not recover their original shape. There have been attempts to build fast acting gate valves for the purpose of isolating the accelerator tank’s load of SF6 in the event of a breach in a tube. While it seemed like a good idea the force of the valve closing at high speed could damage the gate seal causing the valve to leak. Designers must use care to ensure that a standard high differential pressure rated gate valve isn’t adequate before launching into these expense type valves. 11. External Interfaces 11.1 Electrical Feedthroughs a) Low Voltage, Low Current There are few applications where voltages greater than 24Vac are used within the vacuum space. For these voltages at a few amps coaxial feedthroughs such as BNC, SHV, MHV, etc, are often used in place of more expensive dedicated commercial types. In one application 200Vdc is used for faraday Cup suppressors but current is only a few micro-amps at most. Notes: • Do not use multi-pin signal feedthroughs to carry voltages unless the pins used for voltage can be a few unused pins away from used signal pins. - 33 -
Page 1 and 2: Vacuum Technology and Vacuum Design
Page 3 and 4: Contents Page Chapter 1 - Vacuum de
Page 5 and 6: 3.5 Reynolds Number (Re) 3.6 Viscou
Page 7 and 8: • Top and bottom flanges to have
Page 9 and 10: • STAR utilises many of the major
Page 11 and 12: • For all other vacuum equipment
Page 13 and 14: 1. Terminology ANTARES - Australian
Page 15 and 16: Non-cylindrical chambers must be ca
Page 17 and 18: 3.9 Design by numbers This is a mat
Page 19 and 20: The ultimate vacuum is improved by
Page 21 and 22: pump. Slowly open the pump out valv
Page 23 and 24: Precautions • Before venting a va
Page 25 and 26: • Changing faulty seals - cleanin
Page 27 and 28: can be used on stainless steel with
Page 29 and 30: • Some steps for inner rings have
Page 31: Most Conflat flanges have imperial
Page 35 and 36: The third type is magnetically coup
Page 37 and 38: 13. Pumping 13.1 General It is not
Page 39 and 40: • On ANTARES the Pfeiffer brand i
Page 41 and 42: The pressure exerted from a vacuum
Page 43 and 44: as Avogadro's number. The mass of t
Page 45 and 46: pumped at the highest flow rate ach
Page 47 and 48: Gas Formula Molecular weight - 47 -
Page 49 and 50: It is normally specified in Pa.l.s
Page 51 and 52: 4. Limitations The most fundamental
Page 53 and 54: connection. Even some metals (Cd, Z
Page 55 and 56: adequately tight if the equilibrium
Page 57 and 58: Appendix 1 - Structural Calculation
Page 59 and 60: Factor tables for thickness calcula
Page 61 and 62: Factor A table for Stainless Steels
Page 63 and 64: PCTFE exhibits high chemical resist
Page 65 and 66: ass has good corrosion resistance t
Page 67 and 68: Glass is similar to ceramics in thi
Page 69 and 70: Appendix 4 - Surface finishing In m
Page 71 and 72: Appendix 5 - Vapour Pressures conti
Page 73 and 74: Aluminium 6061-T4 Aluminium 6061-T4
Page 75 and 76: SS H2 glow discharge - 150°C SS Ar
Page 77 and 78: Araldite (moulded) Araldite D Arald
Page 79 and 80: fittings and equipment protruding f
Page 81 and 82: References • Berman, Vacuum Engin
Page 83 and 84:
Vacuum Technology and Vacuum Design
Page 85 and 86:
5.3 Fumes form exhausts 5.4 Earthin
Page 87 and 88:
Chapter 1 Vacuum design standards a
Page 89 and 90:
• Electric arc with rods is not r
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8. Lubricants, vacuum greases and e
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Chapter 2 Design Criteria, Informat
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mostly imperial. Typically, UNC and
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3.5 Flexible design It is prudent t
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option. This is where add on vacuum
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The accelerator beam lines are divi
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Water vapour and residual solvents
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• Cryopumps must not be operated
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Final clean. It is recommended that
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8.3 Edwards This is no longer a pre
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ISO-F flanges are more of a traditi
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join sections of beam line or equip
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• Feedthroughs can be purchased i
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12. Internal Devices There are many
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services, can be regenerated withou
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Chapter 3 Overview of Basic Vacuum
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2. Pressure Fundamentals 2.1 Genera
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Pressure (Pa) Molecules / cm 3 Mole
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By evaluating the Knudsen (Kn) and
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table in “Conductivities” below
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Where: qpV = Throughput flow rate p
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Diffusion Permeation Desorption Lea
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4.4 Diffusion with desorption At op
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4.7 Bake-out The following prerequi
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For Hemispherical End (h2): R ≤ 8
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Example 3: For comparison, calculat
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Appendix 2 - Low Outgassing Special
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Appendix 3 - Materials for use in V
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• Polyvinyl Chloride (PVC) is acc
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o Apiezon Sealing Compound Q • Va
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- 70 - Appendix 5 - Critical Vapour
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Appendix 6 - Outgassing tables for
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Stainless steel Stainless steel 304
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PVC 24h @ 95% relative humidity PTF
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Appendix 7 - Local Plant and Safety
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Regular maintenance applied via Acc
Page 163 and 164:
Page 165 and 166:
Contents Page Chapter 1 - Vacuum de
Page 167 and 168:
3.5 Reynolds Number (Re) 3.6 Viscou
Page 169 and 170:
• Top and bottom flanges to have
Page 171 and 172:
• STAR utilises many of the major
Page 173 and 174:
• For all other vacuum equipment
Page 175 and 176:
1. Terminology ANTARES - Australian
Page 177 and 178:
Non-cylindrical chambers must be ca
Page 179 and 180:
3.9 Design by numbers This is a mat
Page 181 and 182:
The ultimate vacuum is improved by
Page 183 and 184:
pump. Slowly open the pump out valv
Page 185 and 186:
Precautions • Before venting a va
Page 187 and 188:
• Changing faulty seals - cleanin
Page 189 and 190:
can be used on stainless steel with
Page 191 and 192:
• Some steps for inner rings have
Page 193 and 194:
Most Conflat flanges have imperial
Page 195 and 196:
on the location of the valve. See t
Page 197 and 198:
The third type is magnetically coup
Page 199 and 200:
13. Pumping 13.1 General It is not
Page 201 and 202:
• On ANTARES the Pfeiffer brand i
Page 203 and 204:
The pressure exerted from a vacuum
Page 205 and 206:
as Avogadro's number. The mass of t
Page 207 and 208:
pumped at the highest flow rate ach
Page 209 and 210:
Gas Formula Molecular weight - 47 -
Page 211 and 212:
It is normally specified in Pa.l.s
Page 213 and 214:
4. Limitations The most fundamental
Page 215 and 216:
connection. Even some metals (Cd, Z
Page 217 and 218:
adequately tight if the equilibrium
Page 219 and 220:
Appendix 1 - Structural Calculation
Page 221 and 222:
Factor tables for thickness calcula
Page 223 and 224:
Factor A table for Stainless Steels
Page 225 and 226:
PCTFE exhibits high chemical resist
Page 227 and 228:
ass has good corrosion resistance t
Page 229 and 230:
Glass is similar to ceramics in thi
Page 231 and 232:
Appendix 4 - Surface finishing In m
Page 233 and 234:
Appendix 5 - Vapour Pressures conti
Page 235 and 236:
Aluminium 6061-T4 Aluminium 6061-T4
Page 237 and 238:
SS H2 glow discharge - 150°C SS Ar
Page 239 and 240:
Araldite (moulded) Araldite D Arald
Page 241 and 242:
fittings and equipment protruding f
Page 243 and 244:
References • Berman, Vacuum Engin
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The pressure exerted from a vacuum
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as Avogadro's number. The mass of t
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pumped at the highest flow rate ach
Page 371 and 372:
Gas Formula Molecular weight - 47 -
Page 373 and 374:
It is normally specified in Pa.l.s
Page 375 and 376:
4. Limitations The most fundamental
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connection. Even some metals (Cd, Z
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adequately tight if the equilibrium
Page 381 and 382:
Appendix 1 - Structural Calculation
Page 383 and 384:
Factor tables for thickness calcula
Page 385 and 386:
Factor A table for Stainless Steels
Page 387 and 388:
PCTFE exhibits high chemical resist
Page 389 and 390:
ass has good corrosion resistance t
Page 391 and 392:
Glass is similar to ceramics in thi
Page 393 and 394:
Appendix 4 - Surface finishing In m
Page 395 and 396:
Appendix 5 - Vapour Pressures conti
Page 397 and 398:
Aluminium 6061-T4 Aluminium 6061-T4
Page 399 and 400:
SS H2 glow discharge - 150°C SS Ar
Page 401 and 402:
Araldite (moulded) Araldite D Arald
Page 403 and 404:
fittings and equipment protruding f
Page 405 and 406:
References • Berman, Vacuum Engin
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