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Prohibited Action

Explosion-Causing Condition

Open drain or fill plug while pump is 

Overpressure plus strong oxidizer

under vacuum, especially when it is hot

Contaminate pump with explosive vapors,

Lower explosive threshold of gas mixtures

powders, or reactive materials

Remove, defeat, or override safety counter-

Overtemperature, overpressure, more 

measures such as pressure and thermal

combustible mixtures

switches and valve sequencer interlocks

Machine or weld without removing all oil

Source of ignition

or solvent residue in pump

Use unsuitable pumping fluid especially 

Lower explosive threshold of gas mixture

in large pumps

Systems larger than 10 inches must be designed with pressure relief devices to provide safe pres-
sure relief from internal explosions. Always recognize that safety devices can fail or malfunction. Pro-
vide redundant protection by installing devices having different failure modes, failure mechanisms,
and failure causes. Be certain that exhaust duct materials are capable of withstanding the corrosivity,
temperature, and pressure of exhausted products.

c. Pressure – Pumps and their components are designed for vacuum service; they are not designed

to be pressurized which could cause them to burst possibly expelling shrapnel at lethal velocities.
Serious accidents have been caused by intentional pressurization of vacuum systems and their
components. Never pressurize any part of a vacuum system for test or any other purpose.
Always provide pressure relief when designing diffusion pumps into systems and ensure that pres-
sure relief motion is limited to safe envelopes. Never permit the following:

Prohibited Action

Result

Block inlet and vent of liquid nitrogen

LN

2

trap and/or lines burst

trap and lines

Close isolation valves at inlet and discharge

Water turns to steam and bursts coils

of main watercooling coils and pump is 
reheated

Pressurize pump body

Body of pump bursts

Hole through vacuum wall

Loss of structural integrity of wall

Summary of Contents for VHS-6

Page 1: ...VHS 6 Diffusion Pump Instruction Manual Varian Vacuum Technologies 121 Hartwell Avenue Lexington MA 02421 3133 781 861 7200 800 8 VARIAN Manual No 6999 01 022 Revision E July 2000 ...

Page 2: ...2 Hong Kong Varian Technologies Asia Ltd Rm 2611 Concordia Plaza New Mandarin Plaza 1 Science Museum Rd Tsimshatsui East Kowloon Hong Kong Tel 852 26206173 Fax 852 26206338 India Varian India PVT LTD 1010 Compotent House 7 Nangal Raya Business Centre New Delhi 110 046 India Tel 91 11 5548444 Fax 91 11 5548445 Italy Varian Vacuum Technologies via Flli Varian 54 10040 Leini Torino Italy Tel 39 011 9...

Page 3: ...ed herein Seller shall have no liability under any warranty express or implied either in fact or by operation of law statutory or otherwise Statements made by any person including representatives of Seller which are inconsistent or in conflict with the terms of this warranty shall not be binding upon Seller unless reduced to writing and approved by an officer of Seller Warranty Replacement and Adj...

Page 4: ...pproved by an industrial hygienist or chemical safety engineer Varian has no control over the use of this equipment and is not responsible for personal injury or damage resulting from its use The safe use and disposal of hazardous or potentially hazardous materials of any kind is the sole responsibility of the user Observe all WARNINGS and CAUTIONS to minimize the serious hazards involved It is th...

Page 5: ... SAFELY AND EFFICIENTLY READ THEM SPECIAL OPERATING CONSIDERATIONS AND PRECAUTIONS WILL BE FOUND IN THE OPERATION INSTRUCTIONS UNINFORMED OR CARELESS OPERATION OF THIS PUMP CAN RESULT IN POOR PERFORMANCE DAMAGE TO THE PUMP OR OTHER PROPERTY SERIOUS BODILY INJURY AND POSSIBLE DEATH USERS OF THIS EQUIPMENT SHOULD BE ALERT TO TWO LEVELS OF HAZARDS IDENTIFIED BY THE FOLLOWING SYMBOLS Designers of syst...

Page 6: ...id level sensors with feedback to an interlock on the heater power supply Insufficient water flow through the Use water flow sensor and feedback to interlock on the heater main cooling coils power supply Water trapped between inlet and Provide vent or pressure relief valves for both quick cool coil outlet of quick cool coil or liquid and liquid nitrogen trap nitrogen trapped between inlet and outl...

Page 7: ...e elements are required fuel oxidizer and source of ignition A combination of temperature and pressure can be a source of ignition Most diffusion pump fluids except mercury are fuels Hydrocarbon oils are more prone to oxidize and explode than synthetic silicone based oil Oxidizers can be air a strong oxidizer from a leak or can be deliberately introduced in a process or can be inadvertently admitt...

Page 8: ...ing different failure modes failure mechanisms and failure causes Be certain that exhaust duct materials are capable of withstanding the corrosivity temperature and pressure of exhausted products c Pressure Pumps and their components are designed for vacuum service they are not designed to be pressurized which could cause them to burst possibly expelling shrapnel at lethal velocities Serious accid...

Page 9: ...nd inges tion may produce serious effects Even absorption through the skin can result in moderate toxicity Always ensure that cleaning operations are performed in large well ventilated rooms Use of self contained breathing apparatus may be necessary depending upon the solvent type and vapor concentration in surrounding air e High Voltage Diffusion pumps operate at voltages high enough to kill thro...

Page 10: ... large amount of liquid nitrogen is spilled in a small poorly ventilated room or equipment death from suffocation can result All diffusion pumps are typically cleaned with acetone or alcohol Acetone alcohol and most other solvents are very volatile unstable During cleaning the volatility of these cleaners may permit their gases to displace air and its life supporting oxygen which could cause death...

Page 11: ...as thus displacing air which can kill by asphyxiation Use in a large well ventilated room Use of a self contained breathing apparatus may be necessary Acetone alcohol and other solvents are irritants narcotics depres sants and or carcinogenics Their inhalation and or ingestion may pro duce serious effects Prolonged or continued contact with the skin will result in absorption through the skin and m...

Page 12: ...th lint free clean cloth wash in detergent and water or use a small amount of pump oil WARNING _____________ When lifting some Varian diffusion pumps use power assisted equip ment and trained moving installation personnel to avoid dropping slip ping and or overturning the pump and severely injuring personnel Check weight of equipment before lifting and do not stand under equip ment being moved WAR...

Page 13: ...Thermal Switch 1 4 Section II Operation 2 1 2 1 Startup Procedure 2 1 2 2 Shutdown Procedure 2 2 Section III Maintenance and Service 3 1 3 1 General 3 1 3 2 Periodic Inspection 3 1 3 3 Cleaning 3 1 3 4 Cold Cap Removal Installation 3 2 3 5 Jet Assembly Removal Installation 3 3 3 6 Heater Replacement 3 4 3 7 Adding Pump Fluid 3 4 Section IV Troubleshooting 4 1 4 1 Leakage 4 1 4 2 Outgassing 4 1 4 3...

Page 14: ...0 with std cold cap 1600 with extended cold cap liters sec helium 3000 with std cold cap 2000 with extended cold cap Maximum Throughput 3 5 Torr liters sec at 0 01 Torr 13 3 Pa Maximum Forepressure No Load 0 65 Torr 86 45 Pa Full Load 0 55 Torr 73 15 Pa Backstreaming Rate at Pump Inlet 5 x 10 4 mg cm2 minute with std cold cap Power Required approximately 120 240 208 50 60 Hz single phase Warmup Ti...

Page 15: ...t should be concentric and firmly seated on the bottom of the diffusion pump Using a flashlight check to ensure that the ejector nozzle is directly in line with the foreline The location of the jet is controlled by an indexing pin located on the bottom of the pump e The pump requires no initial cleaning if the required vacuum level is above 10 6 Torr 000133 Pa For pressure below 10 6 Torr 000133 P...

Page 16: ... metal to metal contact f To ensure the integrity of the vacuum connections they should be checked for leaks using a helium mass spectrometer leak detector before operating the vacuum system 1 2 4 Cooling Water Connections a The inlet water fitting near the inlet flange at the top of the pump should be connected to a continuously running water supply at 0 25 gpm and at a temperature of 60 to 80oF ...

Page 17: ... all applicable State local and or industrial codes 1 2 6 Thermal Switch a The pump has been fitted with a manually resettable thermal switch that is preset at the factory This switch is located in a box near the bottom of the pump and provides protection to the pump in the event of excessive fluid loss the loss of cooling water or high inlet pressure b The thermal switch is connected in series wi...

Page 18: ...2 1 STARTUP PROCEDURE a During initial operation of the diffusion pump a fresh charge of diffusion pump oil may go through a degassing process This may result in inlet and foreline pressure fluctuations These pressure fluctuations are normal b Visually inspect the sight glass assembly to ensure that the diffusion pump has been charged with the proper amount of diffusion pump fluid When properly fi...

Page 19: ... diffusion pump Continue to back the diffusion pump with the appro priate mechanical pump b Allow cooling water to flow through the diffusion pump until the pump body temperature located just above the boiler plate has cooled to a temperature of approximately 130 F ...

Page 20: ...ain and by visually checking the level of the fluid through the sight glass A slight discoloration of the fluid does not affect performance Always use new o rings when replacing fill plugs or the sight glass b Loss of fluid can be caused by the following 1 Incorrect venting procedures and or admittance of excessive air or other gas to a hot pump 2 Inadequate water cooling 3 Prolonged operation at ...

Page 21: ...rn on the cooling water m After the pump has been evacuated to a pressure below 0 5 Torr 66 5 Pa turn on the power to the diffusion pump 3 4 COLD CAP REMOVAL INSTALLATION Refer to Figure 3 1 To remove the cold cap proceed as follows a Remove the spring 1 attached by no 6 32 x 3 16 round head screw 2 a flat washer 3 and a lockwasher 4 b Loosen the nut 5 holding the cold cap bracket 6 to the copper ...

Page 22: ... jet assembly proceed as follows a Remove the cold cap from the pump b Unscrew the top cap from the jet assembly c Lift out each section of the jet assembly Do not dent or otherwise damage the jet assembly during disassembly or cleaning d Remove the splash baffle from the pump To install the jet assembly proceed as follows a Place the splash baffle in the bottom of the pump Check that it is locate...

Page 23: ... unit up against the boiler plate Use two nuts tightened finger tight to hold it in place l Secure the remainder of the nuts finger tight then tighten the bolts evenly to a torque of 250 inch pounds m Replace the heater insulation and the cover 3 7 ADDING PUMP FLUID The recommended fluid charge for the VHS 6 diffusion pump is 500 cc The fluid charge will gradually be depleted through use but the p...

Page 24: ... system is a result of gas load divided by pumping speed P Q S If the gas load Q exceeds the maximum throughput capability of the diffusion pump the diffusion pump will not function and the pumping action will essentially be performed by the mechanical backing pump To estimate the gas load isolate the system from all pumps after evacuation and measure the rate of pressure rise The gas load created...

Page 25: ...remove water Low heat input Check heaters Low oil level Add oil Malfunctioning pump assembly Check and repair or replace Improperly located jets Damaged jet system Inlet pressure surges Incorrect heater voltage Check and correct voltage Fluid outgassing Condition fluid by operating the pump for a few hours Leak in system ahead of pump inlet Check and correct High chamber Forepressure too high Chec...

Page 26: ...eater Clamping Plate 86088301 Heater Cover Plate L8998001 Heater Insulating Blanket L8997001 Heater Cover K0377184 O Ring Kit includes 3 Butyl inlet flange O ring Parker No 2 267 3 Buna N foreline flange O ring Parker No 2 332 10 Viton fill and drain O rings old style Parker No 2 112 10 Viton fill and drain O rings new style Parker No 2 113 1 Sight glass O ring Parker No 2 035 1 Sight glass O ring...

Page 27: ...Replacement Parts 5 2 ...

Page 28: ...Replacement Parts 5 3 ...

Page 29: ...0 K 10 CFF Inlet Flange OD 11 00 279 9 45 240 9 97 253 Inlet Flange ID 7 88 200 7 72 196 7 88 200 Inlet Flange Thickness 0 75 19 0 47 12 0 96 24 Inlet Flange Bolt Circle 9 50 241 N A N A 9 12 232 Inlet Flange Number of Holes 8 N A 24 Inlet Flange Hole Size 0 81 21 N A N A 0 33 8 O ring Groove ID 8 20 208 N A N A N A N A O ring Groove Width 0 18 4 N A N A N A N A Foreline Flange Nominal Size 11 2 A...

Page 30: ...Replacement Parts 5 5 Note Speed curves were generated according to AVS Standard 4 1 1 Torr 133 Pa VHS 6 Speed and Throughput Curves ...

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