agilent diffusion pumps - ideal vac the pump. as a result, agilent diffusion pumps offer you the...

AGILENT DIFFUSION PUMPS

2-3 Features and Benefits

4-5 Typical Applications

6-29 Pump Models

30 Fluids

31 Baffles

32-35 Technical Notes

www.idealvac.com

2

DIFFUSION PUMPS FEATURES AND BENEFITS

Agilent has earned its position as the leading diffusion pump manufacturer in the world by listening to customer needs and by continuously improving the performance and reliability of our benchmark designs. Throughout our more than forty years of leadership in the industry, we have consistently produced pumps that provide the most efficient means of converting heat into pumping throughput.Our experience has allowed us to optimize the design of every element of the pump. As a result, Agilent diffusion pumps offer you the lowest cost of ownership available for many high vacuum-pumping applications.

Low Cost of OwnershipBy providing the highest throughput available per unit of power, reduced cooling water requirements, and rugged, durable construction, Agilent delivers large volume pumping at the lowest total cost to you.

World-class Service, Training and SupportAgilent’s application consulting capability makes use of our unparalleled experience to identify the optimal solution for you. And we invite you to take advantage of our industry leading worldwide service and support programs and award winning vacuum training classes to maximize system uptime and productivity.

Options to Address Your NeedsMany applications have unique requirements. Agilent can provide additional features such as Halo or custom baffles to eliminate additional backstreaming, and a Quick Cool Coil option to accelerate system cycle times.

Fully Optimized JetUsing our long and varied experience Agilent designs and produces vapor jets that deliver the highest throughput, pressure stability, and tolerable foreline pressure available, while reducing backstreaming to a minimum.

3

DIFFUSION PUMPS

Diffu

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umps

Built for Production VolumesOur success is in helping you meet the exacting requirements of your production process. Our pumps deliver superior pumping at high pressure and high gas flow conditions, and handle gas load variations that are typical of large volume production.

Robust Boiler DesignThrough optimized boiler design, Agilent pumps are stable and reliable under widely varying operating conditions. This temperature stability prolongs fluid life as well. Thermal protection switches prevent system over-temperature conditions.

Easy to MaintainMaintaining uptime is critical so we have simplified operation and maintenance. A sight glass provides visual indication of status when cold or hot and under vacuum. A gauge port facilitates system troubleshooting.

4

TYPICAL APPLICATIONS

As the worldwide diffusion pump market leader, Agilent produces the most comprehensive family of pumps, ranging from 2 in. to 35 in. in diameter, and is the only broad-line, U.S.-based manufacturer.

The diffusion pump is the most common type of pump for use in high vacuum applications. These vapor jet pumps are one of the oldest and most reliable ways to create a vacuum. Since the chamber itself has no moving parts aside from the oil droplets, a vacuum diffusion pump can operate with stability over long periods.

In all diffusion pumps, a small amount of backstreaming occurs. Backstreaming is the migration of minute levels of oil that move in the opposite direction— toward the inlet of the pump and into the process stream, which may be the stage of an electron microscope or a welding chamber. In some applications, minor backstreaming has no impact; in others, where the purity of materials is critical, backstreaming cannot be tolerated. For this reason, systems typically add an optically dense baffle of varying design to deflect oil particles before they can reach the process stream.

Diffusion pumps are in wide use because they have several advantages: They are reliable, simple in design, operate without noise or vibration, and are relatively inexpensive to operate and maintain. In fact, diffusion pumping is still the most economical means of creating high-vacuum environments. These pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps.

With the proper choice of motive fluids, traps, baffles, and valves, diffusion pumps can be used in a wide variety of applications and over pressure ranges from 1 x 10-3 Torr to 2 x 10-11 Torr

Key features of Agilent diffusion pumps include:

• High pumping speeds • High throughput • High forepressure tolerance • Low ultimate pressure • Excellent backstreaming characteristics • Long-term reliability

Courtesy of Mill Lane Engineering Courtesy of Materials Research Furnaces, Inc.

5

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DIFFUSION PUMPS

Vacuum FurnacesVacuum furnace applications require pumps that are capable of achieving stable pressures in high gas flow environments. Additionally, furnace operators need shorter cycle times to accomplish efficient processing of heat-treated material batches. Furnace operators derive these benefits from Agilent vapor diffusion pumps, because the high throughput and low backstreaming rates of the pumps accommodate high material outgassing and allow higher cross-over pressures for shorter cycle times.

MetallizingIn web and roll coating systems, Agilent diffusion pumps have the ability to pump high gas loads making them the perfect choice for continuous production applications.

Large Area Coating/Thin Film DepositionDue to it’s simplicity, high performance and low initial costs, the diffusion pump remains a primary pumping mechanism

for large area coating systems. The large pumps used in this application come equipped with sight glass and drain assemblies and are also available with ASA or ISO flanges.

Coatings (Optical, Electronics, Protective)With low ultimate pressure, high speed, high throughput and high tolerable forepressure, Agilent diffusion pumps are the best choice for developmental and production systems.

Molecular BeamsThe foreline ejector stage provides high tolerable forepressure and a large surface area for efficient degassing of compressed fluid, while the foreline baffle minimizes fluid loss even under high throughput conditions.All Agilent pumps incorporate an ejector stage as well as full fractionating jets. HS series pumps create high speed and low ultimate pressure, high throughput and high tolerable forepressure and low backstreaming combine to make the HS series the best diffusion pump. Additionally, pumps are equipped with full thermal protection.

6

PUMP SPECIFICATIONS

AX-65 HS-2 VHS-4 VHS-6 VHS-250 VHS-10 VHS-400 HS-16 HS-20 HS-32 NHS-35

Previous model number 0160 0183 0184 0178 0185 0182 0164 0165 0167 0169

Pumping speed*, l/s (operating range)AirHelium & hydrogen

Pumping speed AVS 4.1 (1963)*

6590

160200285

750940

1,200

1,5501,9302,400

2,1252,6603,700

3,6504,5605,300

4,5005,6258,000

6.0007,50010,000

10,00012,50017,500

17,30021,62532,000

28,00035,00050,000

Maximum forepressure, Torr (mbar)No loadFull load

0.75 (1.00)0.60 (0.78)

0.55 (0.72)0.40 (0.52)

0.65 (0.86)0.55 (0.73)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.50 (0.65)0.35 (0.45)

0.55 (0.71)0.40 (0.52)

Maximum throughput,T-l/s (mbar-l/s) In operating range@ 1 x 10-2 Torr (1.3 x 10-2 mbar)

0.19 (0.25)0.30 (0.40)

0.60 (0.80)0.70 (0.93)

1.5 (2.0)2.5 (3.2)

2.4 (3.2)3.5 (4.5)

2.6 (3.5)3.5 (4.5)

6.3 (8.4)7.5 (10.0)

6.3 (8.4)7.5 (10.0)

9.5 (11.7) at 8100 W11.5 (15.3) at 8100 W

12.5 (16.7)18 (23.4)

30 (40)35 (45.5)

25 (33)35 (45.5)

Minimum recommended backing pumpfor maximum throughput, cfm (m3/hr) 0.15 (0.25) 5.0 (8.5) 10 (17) 17.0 (28.9) 17.0 (28.9) 30 (51) 30 (51) 80 (136) 100 (170) 300 (510) 300 (510)

Backstreaming rate at inlet flangemg/cm2/min (standard cold cap)* 2 x 10-4 1 x 10-3 5 x 10-4 5 x 10-4 5 x 10-4 5 x 10-4 1 x 10-3 1.5 x 10-3 1.5 x 10-3 7 x 10-4 5 x 10-4

Warmup time, minutes 7 15 10 10 10 15 15 30 45 60 60

Cooldown time, minuteswith quick cool coil, where applicable 10 10 10 10 10 25 25 30 45 60 60

Fluid charge 30 cc 100 cc 300 cc 500 cc 500 cc 1,000 cc 1,000 cc 3 U.S. qts. (2.8 liters)

5 U.S. gal.(4.7 liters)


3 U.S. gal. (11.3 liters)

Electrical requirements1 ph

50/60 Hz90/115/165/220 V

1 ph50/60 Hz120/240 V

1 ph50/60 Hz

120/208/240 V

1 ph50/60 Hz

120/208/240 V

1 ph50/60 Hz

120/208/240 V

3 ph50/60 Hz

208/240/380/480 V

3 ph50/60 Hz

208/240/380/480 V

3 ph50/60 Hz

240/415/480 V

3 ph50/60 Hz

240/415/480 V

3 ph50/60 Hz

240/415/480 V50/60 Hz

240/415/480 V

Power, watts 200/250 450 1,45 2,2 2,2 4,4 4,4 8,100/9,600 12 24 24

Cooling water, U.S. gpm (l/hr)at 60-80 °F (15-26 °C) N/A 0.1 (20) 0.15 (30) 0.25 (50) 0.25 (50) 0.40 (80) 0.40 (80) 1.5 (300) 1.5 (300) 4.0 (800) 4.0 (800)

*For descriptions of pumping speed and backstreaming measurements, please see page 34.

7

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umps

DIFFUSION PUMPS

AX-65 HS-2 VHS-4 VHS-6 VHS-250 VHS-10 VHS-400 HS-16 HS-20 HS-32 NHS-35

Previous model number 0160 0183 0184 0178 0185 0182 0164 0165 0167 0169

Pumping speed*, l/s (operating range)AirHelium & hydrogen

Pumping speed AVS 4.1 (1963)*

6590

160200285

750940

1,200

1,5501,9302,400

2,1252,6603,700

3,6504,5605,300

4,5005,6258,000

6.0007,50010,000

10,00012,50017,500

17,30021,62532,000

28,00035,00050,000

Maximum forepressure, Torr (mbar)No loadFull load

0.75 (1.00)0.60 (0.78)

0.55 (0.72)0.40 (0.52)

0.65 (0.86)0.55 (0.73)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.65 (0.85)0.55 (0.72)

0.50 (0.65)0.35 (0.45)

0.55 (0.71)0.40 (0.52)

Maximum throughput,T-l/s (mbar-l/s) In operating range@ 1 x 10-2 Torr (1.3 x 10-2 mbar)

0.19 (0.25)0.30 (0.40)

0.60 (0.80)0.70 (0.93)

1.5 (2.0)2.5 (3.2)

2.4 (3.2)3.5 (4.5)

2.6 (3.5)3.5 (4.5)

6.3 (8.4)7.5 (10.0)

6.3 (8.4)7.5 (10.0)

9.5 (11.7) at 8100 W11.5 (15.3) at 8100 W

12.5 (16.7)18 (23.4)

30 (40)35 (45.5)

25 (33)35 (45.5)

Minimum recommended backing pumpfor maximum throughput, cfm (m3/hr) 0.15 (0.25) 5.0 (8.5) 10 (17) 17.0 (28.9) 17.0 (28.9) 30 (51) 30 (51) 80 (136) 100 (170) 300 (510) 300 (510)

Backstreaming rate at inlet flangemg/cm2/min (standard cold cap)* 2 x 10-4 1 x 10-3 5 x 10-4 5 x 10-4 5 x 10-4 5 x 10-4 1 x 10-3 1.5 x 10-3 1.5 x 10-3 7 x 10-4 5 x 10-4

Warmup time, minutes 7 15 10 10 10 15 15 30 45 60 60

Cooldown time, minuteswith quick cool coil, where applicable 10 10 10 10 10 25 25 30 45 60 60

Fluid charge 30 cc 100 cc 300 cc 500 cc 500 cc 1,000 cc 1,000 cc 3 U.S. qts. (2.8 liters)



3 U.S. gal. (11.3 liters)

Electrical requirements1 ph

50/60 Hz90/115/165/220 V

1 ph50/60 Hz120/240 V

1 ph50/60 Hz

120/208/240 V

1 ph50/60 Hz

120/208/240 V

1 ph50/60 Hz

120/208/240 V

3 ph50/60 Hz

208/240/380/480 V

3 ph50/60 Hz

208/240/380/480 V

3 ph50/60 Hz

240/415/480 V

3 ph50/60 Hz

240/415/480 V

3 ph50/60 Hz

240/415/480 V50/60 Hz

240/415/480 V

Power, watts 200/250 450 1,45 2,2 2,2 4,4 4,4 8,100/9,600 12 24 24

Cooling water, U.S. gpm (l/hr)at 60-80 °F (15-26 °C) N/A 0.1 (20) 0.15 (30) 0.25 (50) 0.25 (50) 0.40 (80) 0.40 (80) 1.5 (300) 1.5 (300) 4.0 (800) 4.0 (800)

*For descriptions of pumping speed and backstreaming measurements, please see page 34.

8

PUMP MODELS

Technical SpecificationsPumping speed*, operating range 65l/secair,90l/sHeandH2Maximum throughput 0.19T-l/s(0.25mbar-l/s)inoperatingrange,0.30T-l/s(0.40mbar-l/s)@0.01TorrCompression ratio 4x107(air),2x106(helium)Operating range 3x10-3to<5x10-8Torr(3.9x10-3to6.5x10-8mbar)Maximum forepressure Noload:0.75Torr(1.00mbar)

Fullload:0.60Torr(0.78mbar)Backstreaming rate** Withcoldcap:<2x10-4mg/cm2/min

Withbaffle:<2x10-5mg/cm2/minRecommended backing pump ≥1.5cfm(2.5m3/hr)Warmup time 7minutesCooldown time 10minutesFluid charge 30ccElectrical requirements 1ph,50/60Hz,90/115/165/220VACPump power 200/250wattsAir cooling 30cfm** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent AX-65

Dimensions: inches (millimeters)

9

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Inlet pressure (Torr)

Inlet pressure (mbar)

010-8

Air s

peed

(l/s

ec)

10

10-7 10-6 10-5 10-4 10-3 10-2 10-1

30

50

70

900.75

0.60

0.45

0.30

0.15

0

Thro

ughp

ut (T

orr-l

/sec

)

10-110-7 10-6 10-5 10-4 10-3 10-2

Description Wt. kg(lbs) Part Number KF-50 ISO-6AX-65withstandardcoldcap, 3.6(8.0) L9670301 L9707301 115V,250WAX-65withinternalbaffle, 3.6(8.0) L9670311 L9707311 115V,250WAX-65withstandardcoldcap, 3.6(8.0) L9670302 L9707302 220V,250WAX-65withinternalbaffle, 3.6(8.0) L9670312 L9707312 220V,250WAX-65withstandardcoldcap, 3.6(8.0) L9670303 L9707303 115V,200WAX-65withinternalbaffle, 3.6(8.0) L9670313 L9707313 115V,200WAX-65withstandardcoldcap, 3.6(8.0) L9670304 L9707304 220V,200WAX-65withinternalbaffle, 3.6(8.0) L9670314 L9707314 220V,200WAX-65withstandardcoldcap, 3.6(8.0) L9670305 L9707305 90V,250WAX-65withinternalbaffle, 3.6(8.0) L9670315 L9707315 90V,250WAX-65withstandardcoldcap, 3.6(8.0) L9670306 L9707306 165V,250WAX-65withinternalbaffle, 3.6(8.0) L9670316 L9707316 165V,250W

Description Wt.kg(lbs) Part Number

AccessoriesSantovac5diffusionpumpfluid,40cc 0.5(1.0) 695405001Santovac5diffusiondumpfluid,65cc 0.9(2.0) 695405002Internalbafflekit 0.9(2.0) R1160065Centeringringforinletflange,NW50 0.5(1.0) KC50SBCenteringringforinletflange,ISO-63 0.2(0.5) IC063SVCenteringringforforelineflange,NW16 0.2(0.5) KC16SBInstallationandOperationManual 699901062 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(oneheaterharnessrequiredperpump)200W,115Vheaterharness 0.5(1.0) L9994307 (forusewithInvoil704orequivalent)250W,115Vheaterharness 0.5(1.0) L9994303 (forusewithSantovac5orequivalent)200W,220Vheaterharness(foruse 0.5(1.0) L9994308 (forusewithInvoil704orequivalent)250W,220Vheaterharness 0.5(1.0) L9994304 (forusewithSantovac5orequivalent)250W,90Vheaterharness 0.5(1.0) L9994301 (forusewithSantovac5orequivalent)250W,165Vheaterharness 0.5(1.0) L9994302 (forusewithSantovac5orequivalent)Overtemperaturethermalswitch 0.5(1.0) L9964001 (includedwitheachheaterharness)Pumpreadythermalswitch(optional) 0.5(1.0) L9964002

Ordering Information

NOTE • All pumps have NW-16 foreline • See page 30 for Santovac 5 diffusion pump fluid • Mounted cooling fan included with each pump

(P/N 661300138) • Overtemperature thermal switch set to open at 365 °F (182 °C)

• Use 250W heater with polyphenyl ether fluids (such as Santovac 5). Use 200 W heater for other fluids.

AX-65 - Pumping Speed - Air/N2

Pumpingspeed/Coldcap Pumpingspeed/Halobaffle Throughput

10

6(152.4)

4.78(121.4)

12.69(322)

.84(21.3)

DIA O.D.


Technical SpecificationsPumping speed, operating range 160l/sair,200l/sHeandH2Pumping speed*,AVS 4.1(1963) 285l/sairMaximum throughput 0.60T-l/s(0.80mbar-l/s)inoperatingrange,0.70T-l/s(0.93mbar-l/s)@ 0.01TorrOperating range 3.7x10-3to<5x10-8Torr,(4.9x10-3to<6.510-8mbar)Maximum forepressure Noload:0.55Torr(0.71mbar)

Fullload:0.40Torr(0.52mbar)Recommended backing pump ≥5cfm(8.5m3/hr)Backstreaming rate**,standard cold cap <1x10-3mg/cm2/minWarmup time 15minutesCooldown time 10minutes(withquickcoolcoil)Fluid charge 100ccElectrical requirements 1ph,50/60Hz,120/240VACPump power 450wattsCooling water requirements 0.1gpm(20l/hr)at60-80°F(15-26°C)Water connections ⅛in.FPT**For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

PUMP MODELS

► Agilent HS-2

11

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010-8

Air s

peed

(l/s

ec)

10-7 10-6 10-5 10-4 10-3 10-2 10-1

50

100

150

200 1.6

1.2

0.8

0.4

0

Thro

ughp

ut (T

orr-l

/sec

)



10-110-7 10-6 10-5 10-4 10-3 10-2

Description Wt. kg(lbs) Part Number

ASAWithstandardcoldcap,120V 20.0(9.0) 82906301Withstandardcoldcap,240V 20.0(9.0) 82906302

Description Wt. kg(lbs) Part NumberWater-cooledbafflewithASAflanges 10.0(4.5) F9453302Santovac5diffusionpumpfluid,500cc 2.5(1.1) 695405005 pumpfluid,500ccInstallationandOperationManual 699901150 (downloadfromwww.agilent.com/chem/vacuum)


Replacement Parts (oneheaterrequiredperpump)350W,120Vheater(HS2A) 1.0(0.5) 647301100350W,240Vheater(HS2A) 1.0(0.5) 647301125450W,120Vheater 1.0(0.5) 647302125450W,240Vheater 1.0(0.5) 647302150Heaterblock(onerequiredperpump) 1.0(0.5) 82920001Heaterplaten(onerequiredperpump) 1.0(0.5) 82918301Replacemento-ringkit,(5Inletflange 1.0(0.5) K0377159 o-rings(butyl2-338))


NOTE • Inlet flange: nominal 2 in. ASA flange with 6 in. OD • Foreline flange: 0.84 in. diameter tube • See page 31 for baffles • See page 30 for santovac 5 diffusion pump fluid

HS-2 Pumping Speed - Air/N2

Pumpingspeed Throughput

12

PUMP MODELS

Technical SpecificationsPumping speed*, operating range 750l/sair,940l/sHe/H2Pumping speed*, AVS 4.1(1963) 1,200l/sairMaximum throughput 1.5T-l/s(2.0mbar-l/s)inoperatingrange,2.5T-l/s(3.2mbar-l/s)@ 0.01TorrOperating range 2x10-3to<5x10-9Torr(2.7x10-3to<6.5x10-9mbar)Maximum forepressure Noload:0.65Torr(0.86mbar)

Fullload:0.55Torr(0.73mbar)Recommended backing pump ≥10cfm(17m3/hr)Backstreaming rate**,standard cold cap <5x10-4mg/cm2/minWarmup time 10minutesCooldown time 10minutes(withquickcoolcoil)Fluid charge 300ccElectrical requirements 1ph,50/60Hz,120/208/240VACPump power 1450wattsCooling water requirements 0.15gpm(30l/hr)at60-80°F(15-26°C)Water connections ⅛in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent VHS-4


13

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DIFFUSION PUMPS

010-8

Air s

peed

(l/s

ec)

10-7 10-6 10-5 10-4 10-3 10-2 10-1

200

600

800

1000 5

4

3

1

0

Thro

ughp

ut (T

orr-l

/sec

)

2400


Inlet pressure (mbar)10-110-7 10-6 10-5 10-4 10-3 10-2

Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type VHS-4 Pump ASA ISOVHS-4withstandardcoldcap 120V 25.0(55.0) 86460301 L6256301VHS-4withextendedcoldcap 120V 25.0(55.0) 86460311 L6256311VHS-4withstandardcoldcap 208V 25.0(55.0) 86460306 L6256306VHS-4withextendedcoldcap 208V 25.0(55.0) 86460316 L6256316VHS-4withstandardcoldcap 240V 25.0(55.0) 86460302 L6256302VHS-4withextendedcoldcap 240V 25.0(55.0) 86460312 L6256312

Accessories Page Weightkg(lbs) Part NumberWater-cooledbafflewithASAflanges 31 4.5(10.0) F8286304Water-cooledbafflewithISOflanges 31 4.5(10.0) F8286305CenteringringforISOinletflange,160K 0.5(1.0) IC160SVCenteringringforISOforelineflange,KF40 0.2(0.5) KC40SVSantovac5diffusionpumpfluid,500cc 30 1.1(2.5) 695405005InstallationandOperationManual 699901021 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(oneheaterrequiredperpump)1450W,120Vheater 0.5(1.0) 6473042051450W,208Vheater 0.5(1.0) 6473042101450W,240Vheater 0.5(1.0) 647304250Heaterclamp(onerequiredperpump) 1.0(2.0) 88164301VHS-4heaterwire,10AWG,24inches(3perpumprequired) 0.5(0.2) X3901-68001Replacemento-ringkit(kitcontains:3inletflangeo-rings(butyl2-258), 0.5(1.0) K0377183 10fillanddraino-rings(Viton2-113),sightglasso-ringandgasket)Thermalswitch(setat300°F–147°C) 0.5(1.0) 642906025Extendedcoldcap 31 0.5(1.0) F6898301Sightglassrepairkit L8908301NOTE • Inlet flange 4 in. ASA , foreline flange KF40

• Inlet flange ISO 160K, foreline flange ISO KF40 • Pumps with ISO flanges do not include required centering rings

VHS-4 Pumping Speed - Air/N2

Pumpingspeed/Standardcoldcap Pumpingspeed/Extendedcoldcap Throughput

14

PUMP MODELS

Technical SpecificationsPumping speed, operating range 1,550l/sair,1,930l/sHe/H2Pumping speed*, AVS 4.1(1963) 2,400l/sairMaximum throughput 2.4T-l/s(3.2mbar-l/s)inoperatingrange,3.5T-l/s(4.5mbar-l/s)@ 0.01TorrOperating range 1.5x10-3to<5x10-9Torr(2x10-3to<6.5x10-9mbar)Maximum forepressure Noload:0.65Torr(0.85mbar)

Fullload:0.55Torr(0.72mbar)Recommended backing pump ≥17cfm(29m3/hr)Backstreaming rate**, standard cold cap <5x10-4mg/cm2/minWarmup time 10minutesCooldown time 10minutes(withquickcoolcoil)Fluid charge 500cc–exactfluidchargeavailableElectrical requirements 1ph,50/60Hz,120/208/240VACPump power 2200wattsCooling water requirements 0.25gpm(50l/hr)at60-80°F(15-26°C)Water connections ⅛in.FPTTee**For an explanation of pumping speed measurements, please see page 34.**Refer to page 32 for a description of test methods.

► Agilent VHS-6


15

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P

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DIFFUSION PUMPS

010-8

Air s

peed

(l/s

ec)

10-7 10-6 10-5 10-4 10-3 10-2 10-1

400

1200

1600

2000 5

4

3

1

0

Thro

ughp

ut (T

orr-l

/sec

)

2800



Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type VHS-6 Pump ASA ISOVHS-6withstandardcoldcap 120V 34.0(75.0) 85826301 L6193301VHS-6withextendedcoldcap 120V 34.0(75.0) 85826311 L6193311VHS-6withstandardcoldcap 208V 34.0(75.0) 85826306 L6193306VHS-6withextendedcoldcap 208V 34.0(75.0) 85826316 L6193316VHS-6withstandardcoldcap 240V 34.0(75.0) 85826302 L6193302VHS-6withextendedcoldcap 240V 34.0(75.0) 85826312 L6193312Accessories Page Weightkg(lbs) Part NumberWater-cooledbafflewithASAflanges 31 7.0(15.0) F8277306Water-cooledbafflewithISOflanges 31 7.0(15.0) F8277307Santovac5diffusionpumpfluid,500cc(exactpumpcharge) 30 1.1(2.5) 695405005CenteringringforISOinletflange,200K 0.5(1.0) IC200SVCenteringringforISOforelineflange,KF50 0.2(0.5) KC50SVInstallationandOperationManual 699901022 (downloadfromwww.agilent.com/chem/vacuum)Replacement Parts(oneheaterrequiredperpump)2200W,120Vheater 0.5(1.0) 6473061252200W,208Vheater 0.5(1.0) 6473061752200W,240Vheater 0.5(1.0) 647306225Heaterclampingassembly(includesclampingplate,coverplate,insulator) 86643301Heatercoverplate(onerequiredperpump) 1.0(2.0) 86088001Heaterinsulator(onerequiredperpump) 0.2(0.5) 86087001Heaterclampingplate(onerequiredperpump) 0.5(1.0) 86086301VHS-6/250heaterwire,10AWG,36inches(3perpumprequired) 0.5(2.0) X3901-68002Replacemento-ringkit(kitcontains:3inletflangeo-rings(butyl2-267), 0.5(1.0) K0377184 3forelineflangeo-rings(butyl2-332),sightglasso-ringandgasket, 10fillanddraino-rings(Viton2-113))Thermalswitch(setat300°F–147°C) 0.5(1.0) 642906025Extendedcoldcap 31 0.5(1.0) F6455001NOTE • Inlet flange 6 in. ASA , foreline flange 1.5 in. ASA

• Inlet flange ISO 200K, foreline flange ISO KF50 • Pumps with ISO flanges do not include required centering rings



16

PUMP MODELS

Technical SpecificationsPumping speed, operating range 2,125l/sair,2,660l/sHe/H2Pumping speed*, AVS 4.1(1963) 3,700l/sairMaximum throughput 2.6T-l/s(3.5mbar-l/s)inoperatingrange,3.5T-l/s(4.5mbarl/s)@ 0.01TorrOperating range 1.2x10-3to<5x10-9Torr(1.6x10-3to<6.5x10-9mbar)Maximum forepressure Noload:0.65Torr(0.85mbar)

Fullload:0.55Torr(0.72mbar)Recommended backing pump ≥17cfm(29m3/hr)Backstreaming rate**, standard cold cap <5.0x10-4mg/cm2/minWarmup time 10minutesCooldown time 10minutes(withquickcoolcoil)Fluid charge 500cc–exactfluidchargeavailableElectrical requirements 1ph,50/60Hz,120/208/240VACPump power 2200wattsCooling water requirements 0.25gpm(50l/hr)Water connections ⅛in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent VHS-250


17

Diffu

sion

P

umps

DIFFUSION PUMPS

Ordering InformationDescription Voltage Weightkg(lbs) Part NumberVHS-250pumpVHS-250withstandardcoldcap 120V 34.0(75.0) K0543301VHS-250withstandardcoldcap 208V 34.0(75.0) K0543306VHS-250withstandardcoldcap 240V 34.0(75.0) K0543302

AccessoriesSantovac5diffusionpumpfluid,500cc(exactpumpcharge) 1.1(2.5) 695405005InstallationandOperationManual 699901020 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(oneheaterrequiredperpump)2200W,120Vheater 0.5(1.0) 6473061252200W,208Vheater 0.5(1.0) 6473061752200W,240Vheater 0.5(1.0) 647306225Heatercoverplate(onerequiredperpump) 1.0(2.0) 86088001Heaterinsulator(onerequiredperpump) 0.2(0.5) 86087001Heaterclampingplate(onerequiredperpump) 0.5(1.0) 86086301VHS-6/250heaterwire,10AWG,36inches(3perpumprequired) 0.5(2.0) X3901-68002Replacemento-ringkit(kitcontains:3inletflangeo-rings(butyl2-379), 0.5(1.0) K0377178 3forelineflangeo-rings(butyl2-332),sightglasso-ringandgasket,10fillanddraino-rings(Viton2-113))

Thermalswitch(setat300°F–147°C) 0.5(1.0) 642906025NOTE • Inlet flange: ISO 250F (bolted, o-ring seal)

• Foreline flange: ASA with 5 in. OD

010-8

Air s

peed

(l/s

ec)

500

10-7 10-6 10-5 10-4 10-3 10-2

1000

2500

3000 6

5

4

0

Thro

ughp

ut (T

orr-l

/sec

)

2000

1500

1

3

2

1

10-1





18

PUMP MODELS

Technical SpecificationsPumping speed, operating range 3,650l/sair,4,560l/sHe/H2Pumping speed*, AVS 4.1(1963) 5,300l/sairMaximum throughput 6.3T-l/s(8.4mbarl/s)inoperatingrange,7.5T-l/s(10.0mbarl/s)@ 0.01TorrOperating range 1.7x10-3to<5x10-9Torrat4400W(2.3x10-3to<6.5x10-9mbar)Maximum forepressure Noload:0.65Torr(0.85mbar)

Fullload:0.55Torr(0.72mbar)Recommended backing pump ≥30cfm(51m3/hr)Backstreaming rate**, standard cold cap <5.0x10-4mg/cm2/minWarmup time 15minutesCooldown time 25minutesFluid charge 1,000ccElectrical requirements 3ph,50/60Hz,208/240/380/480VACPump power 4400wattsCooling water requirements 0.40gpm(80l/hr)Water connections ⅛in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent VHS-10


19

Diffu

sion

P

umps

DIFFUSION PUMPS

010-8

Air s

peed

(l/s

ec)

10-7 10-6 10-5 10-4 10-3 10-2 10-1

1000

3000

4000 12

9

3

0

Thro

ughp

ut (T

orr-l

/sec

)

62000



Description Wt. kg(lbs) Part Number ASA ISOVHS-10withstandard 68(150) F0426307 L5920307 coldcap,208VVHS-10withextended 68(150) F0426317 L5920317 coldcap,208VVHS-10withstandard 68(150) F0426308 L5920308 coldcap,240VVHS-10withextended 68(150) F0426318 L5920318 coldcap,240VVHS-10withstandard 68(150) F0426326 L5920326 coldcap,380VVHS-10withextended 68(150) F0426336 L5920336 coldcap,380VVHS-10withstandard 68(150) F0426309 L5920309 coldcap,480VVHS-10withextended 68(150) F0426319 L5920319 coldcap,480V

Accessories Wt. kg(lbs) Part NumberWater-cooledbafflewithASAflanges 9.0(20.0) F8600310Water-cooledbafflewithISOflanges 9.0(20.0) F8600311


Accessories(Cont'd)CenteringringforISOforeline 0.5(1.0) IC063SV flange,63KInstallationandOperationManual 699901023 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(twoheatersrequiredperpump)2200W,208Vheater 0.5(1.0) 6473101402200W,240Vheater 0.5(1.0) 6473101502200W,380Vheater 0.5(1.0) 6473101602200W,480Vheater 0.5(1.0) 6473101702550W,208Vheater 0.5(1.0) 6473101452550W,240Vheater 0.5(1.0) 6473101552550W,380Vheater 0.5(1.0) 6473101652550W,480Vheater 0.5(1.0) 647310175Heatercrushplate(coversbothheaters; 1.0(2.0) K7667001 onerequiredforpump;replacewhen eitherheaterisreplaced)Heaterclampingplate(onerequiredperpump)0.5(1.0) R2667301VHS-10/400heaterwire,10AWG, 1.0(0.4) X3901-68003 42inches(3perpumprequired)Replacemento-ringkit 1.0(0.5) K0377185 (kitcontains:1inletflangeo-ring (butylF0430001),1forelineflangeo-ring (butyl2-338),sightglasso-ringandgasket, 10fillanddraino-rings(Viton2-113))Thermalswitch(setat300°F–147°C) 0.5(1.0) 642906025Extendedcoldcap 2.0(0.9) L8917301


NOTE • Inlet flange 10 in. ASA, foreline flange 2 in. ASA • Inlet flange ISO 320K, foreline ISO 63K • See page 30 Santovac 5 diffusion pump fluid • Baffles and extended cold caps can be found

on page 31



20

PUMP MODELS

Technical SpecificationsPumping speed, operating range 4,500l/sair,5,625l/sHe/H2Pumping speed*, AVS 4.1(1963) 8,000l/sairMaximum throughput 6.3T-l/s(8.4mbarl/s)inoperatingrange,7.5T-l/s(10.0mbarl/s)@ 0.01TorrOperating range 1.4x10-3to<5x10-9Torr(1.9x10-3to<6.5x10-9mbar)Maximum forepressure Noload:0.65Torr(0.85mbar)

Fullload:0.55Torr(0.72mbar)Recommended backing pump ≥30cfm(51m3/hr)Backstreaming rate**, standard cold cap <1.0x10-3mg/cm2/minWarmup time 15minutesCooldown time 25minutesFluid charge 1,000ccElectrical requirements 3ph,50/60Hz,208/380/480VACPump power 4400wattsCooling water requirements 0.40gpm(80l/hr)Water connections ⅛in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent VHS-400


21

Diffu

sion

P

umps

DIFFUSION PUMPS

010-8

Air s

peed

(l/s

ec)

500

10-7 10-6 10-5 10-4 10-3 10-2

15002000

3000

400045005000 10

8

6

4

2

0

Thro

ughp

ut (T

orr-l

/sec

)

3500

2500

1000

10-1

9

7

5

3

1



Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type VHS-400 Pump ASA ISOVHS-400withstandardcoldcap 208V 75.0(180.0) K4816307 L9767307VHS-400withstandardcoldcap 380V 75.0(180.0) K4816326 L9767326VHS-400withstandardcoldcap 480V 75.0(180.0) K4816309 L9767309VHS-400withstandardcoldcap 240V 75.0(180.0) K4816308 L9767308

Accessories Page Weightkg(lbs) Part NumberCenteringringforISOInletflange,400K 0.5(1.0) IC400SVCenteringringforISOforelineflange,63K 0.5(1.0) IC063SVInstallationandOperationManual 699901023 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(twoheatersrequiredperpump)2200W,208Vheater 1.0(0.5) 6473101402200W,240Vheater 1.0(0.5) 6473101502200W,380Vheater 1.0(0.5) 6473101602200W,480Vheater 1.0(0.5) 6473101702550W,208Vheater 1.0(0.5) 6473101452550W,240Vheater 1.0(0.5) 6473101552550W,380Vheater 1.0(0.5) 6473101652550W,480Vheater 1.0(0.5) 647310175Heatercrushplate(onerequiredperpump;replacewheneitherheaterisreplaced) 2.0(1.0) K7667001Heaterclampingplate(onerequiredperpump) 1.0(0.5) R2667301VHS-10/400heaterwire,10AWG,42inches(3perpumprequired) 1.0(0.4) X3901-68003Replacemento-ringkit(kitcontains:1inletflangeo-ring(butyl2-385), 1.0(0.5) K0377189 forelineflangeo-ring(butyl2-338),sightglasso-ringandgasket, 10fillanddraino-rings(Viton2-113))Thermalswitch(setat300°F–147°C) 1.0(0.5) 642906025NOTE • Inlet flange ISO 400K, foreline flange ISO 63-K.

• Inlet flange non-standard ASA, foreline flange 2 in. ASA. • Pumps with ASA flanges include O-Rings for inlet and foreline flanges • Pumps with ISO flanges do not include centering rings required for inlet and foreline flanges.



22

PUMP MODELS

Technical SpecificationsPumping speed, operating range 6,000l/sair,7,500l/sHeandH2Pumping speed*, AVS 4.1(1963) 10,000l/sairMaximum throughput 8,100W–9.5T-l/s(12.7mbarl/s)inoperatingrange13.5T-l/s(18.0mbar-l/s)@ 0.01Torr

9,600W–12.0T-l/s(16mbarl/s)inoperatingrange11.5T-l/s(15.3mbar-l/s)@ 0.01TorrOperating range 2x10-3to<5x10-8Torrat9,600W(1.3x10-3to<6.5x10-8mbar)Maximum forepressure Noload–0.65Torr(0.85mbar),FullLoad–0.55Torr(0.72mbar)Pump power 8100/9600wattsRecommended backing pump ≥80cfm(136m3/hr)Backstreaming rate**, standard cold cap <1.5x10-3mg/cm2/minWarmup time 30minutesCooldown time 48minutes(30minuteswithoptionalquickcoolcoil)Fluid charge 3quarts(2.8liters)Electrical requirements 3ph,50/60Hz,240/415/480VACCooling water requirements 1.5gpm(300l/hr)at60-80°F(15-26°C)Water connections ¼in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

10-110-7 10-6 10-5 10-4 10-3 10-2

010-8

Air s

peed

(l/s

ec)

10-7 10-6 10-5 10-4 10-3 10-2 10-1

2000

4000

6000

8000 20

15

10

5

0Th

roug

hput

(Tor

r-l/s

ec)



► Agilent HS-16




23

Diffu

sion

P

umps

DIFFUSION PUMPS

Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type HS-16 Pump ASA ISOHS-16withstandardcoldcap 240V 218.0(480.0) 79292308 L5921308HS-16withhalobaffle 240V 218.0(480.0) 79292318 L5921318HS-16withstandardcoldcap 415V 218.0(480.0) 79292326 L5921326HS-16withhalobaffle 415V 218.0(480.0) 79292336 L5921336HS-16withstandardcoldcap 480V 218.0(480.0) 79292309 L5921309HS-16withhalobaffle 480V 218.0(480.0) 79292319 L5921319NOTE • The HS-16 can be ordered with 9600 W heaters by increasing the middle number of the 3-digit suffix by two; eg 79292328

Accessories Page Weightkg(lbs) Part NumberWater-cooledhalobaffle 31 9.0(20.0) K0143316CenteringringforISOforelineflange,100K 0.5(1.0) IC100SVQuickcoolcoil–mustbeinstalledinthefactory FactorySpecialInstallationandOperationManual 699901140 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(threeheatersrequiredperpump)2700W,240V/415Vwithleads 0.5(1.0) 6473160202700W,480Vwithleads 0.5(1.0) 6473160302700W,240V/415Vnoleads–usedonpumpsbuiltbeforeMay‘90 0.5(1.0) 6473160352700W,480Vnoleads–usedonpumpsbuiltbeforeMay‘90 0.5(1.0) 6473160453200W,240V/415Vwithleads 0.5(1.0) 6473160233200W,480Vwithleads 0.5(1.0) 647316033Heatercrushplate(replaceonewitheachnewheater) 0.5(1.0) K4919001Heaterinsulator(threerequiredperpump) 0.5(1.0) 79309001Heaterclampingplate(threerequiredperpump) 4.0(8.0) K4917001HS-16/20/Daltonheaterwire,10AWG,120inches(2perheaterrequired) 1.0(0.4) X3900-68000Replacemento-ringkitforASApumps(kitcontains:1inletflangeo-ring(buna 0.5(1.0) K0377164 48214001),1forelineflangeo-ring(buna2-348),sightglasso-ringandgasket, 8fillanddraino-rings(Viton2-213))Sightglassservicekit(pumpsbuiltbeforeOct.’95) 1.5(3.0) F6097301Upper(water)thermalswitch(setat185°F/85°C) 0.5(1.0) K9050001Lower(boiler)thermalswitch(setat390°F/199°C) 0.5(1.0) K9050002Coldcapgasket/grommet(kitof4) 0.5(1.0) L8839301Coldcapnutandfollower(2each) 0.5(1.0) L8840301NOTE • Inlet flange 16 in. ASA, foreline flange 3 in. ASA

• Inlet flange ISO 500K, foreline flange ISO 100K • Not recommended for use with Santovac 5 • Pumps with ASA flanges include o-rings for inlet and foreline flanges • Pumps with ISO flanges do not include centering rings required for foreline and inlet flanges

24

PUMP MODELS

Technical SpecificationsPumping speed, operating range 10,000l/sair,12,500l/sHeandH2Pumping speed*, AVS 4.1(1963) 17,500l/sairMaximum throughput 12.5T-l/s(16.7mbarl/s)inoperatingrange,18T-l/s(23mbar-l/s)@ 0.01TorrOperating range 1.3x10-3to5x10-8Torr(1.7x10-3to6.5x10-8mbar)Maximum forepressure Noload:0.65Torr(0.85mbar)

Fullload:0.55Torr(0.72mbar)Recommended backing pump ≥100cfm(170m3/hr)Backstreaming rate**, standard cold cap <1.5x10-3mg/cm2/minWarmup time 45minutesCooldown time 85minutesFluid charge 5quarts(4.7liters)Electrical requirements 3ph,50/60Hz,240/415/480VACPump power 12,000wattsCooling water requirements 1.5gpm(300l/hr)at60-80°F(15-26°C)Water connections ¼in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

010-8

Air s

peed

(l/s

ec)

2000

10-7 10-6 10-5 10-4 10-3 10-2 10-1

4000

6000

8000

10000

12000 30

25

20

15

10

5

0

Thro

ughp

ut (T

orr-l

/sec

)



► Agilent HS-20




25

Diffu

sion

P

umps

DIFFUSION PUMPS

Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type HS-20 Pump ASA ISOHS-20withstandardcoldcap 240V 264.0(580.0) 84341308 L5922308HS-20withhalobaffle 240V 264.0(580.0) 84341318 L5922318HS-20withstandardcoldcap 415V 264.0(580.0) 84341326 L5922326HS-20withhalobaffle 415V 264.0(580.0) 84341336 L5922336HS-20withstandardcoldcap 480V 264.0(580.0) 84341309 L5922309HS-20withhalobaffle 480V 264.0(580.0) 84341319 L5922319

Accessories Page Weightkg(lbs) Part NumberWater-cooledhalobaffle 31 11.0(25.0) K1855320CenteringringforISOforelineflange,160K 0.5(1.0) IC160SVQuickcoolcoil–mustbeinstalledinthefactory FactorySpecialInstallationandOperationManual 699901140 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts (sixheatersrequiredperpump)Heater,2000W,240V/415Vwithleads 0.5(1.0) 647320020Heater,2000W,480Vwithleads 0.5(1.0) 647320030Heater,2000W,240V/415Vnoleads–usedonpumpsbuiltbeforeMay‘90 0.5(1.0) 647320060Heater,2000W,480Vnoleads–usedonpumpsbuiltbeforeMay‘90 0.5(1.0) 647320070Heatercrushplate(replaceonewitheachnewheater) 0.5(1.0) K7108001Heaterclampingplate(sixrequiredperpump) 4.0(8.0) K7107001Heaterinsulator(onerequiredperpump) 0.5(1.0) L6514001HS-16/20/Daltonheaterwire,10AWG,120inches(2perheaterrequired) 1.0(0.4) X3900-68000Replacemento-ringkitforASApumps(kitcontains1inletflangeo-ring(butyl84349002), 0.5(1.0) K0377165 1forelineflangeo-ring(buna2-432),sightglasso-ringandgasket,8filland draino-rings(Viton2-213)Sightglassservicekit(pumpsbuiltbeforeOct.’95) 1.5(3.0) F6097301Upper(water)thermalswitch(setat185°F/85°C) 0.5(1.0) K9050001Lower(boiler)thermalswitch(setat390°F/199°C) 0.5(1.0) K9050002Coldcapgasket/grommet(kitof4) 0.5(1.0) L8839301Coldcapnutandfollower(2each) 0.5(1.0) L8840301NOTE • Inlet flange 20 in. ASA, foreline flange 4 in. ASA

• Inlet flange ISO 630K, foreline flange ISO 160K • Not recommended for use with Santovac 5 • Pumps with ASA flanges include o-rings for inlet and foreline flanges • Pumps with ISO flanges do not include centering rings required for foreline and inlet flanges

26

PUMP MODELS

26.50(673)

46.75(1187)

68.50(1740)

Technical SpecificationsPumping speed, operating range 17,300l/sair,21,625l/sHeandH2Pumping speed*, AVS 4.1(1963) 32,000l/sairMaximum throughput 30T-l/s(40mbarl/s)inoperatingrange,35T-l/s(45mbar-l/s)@ 0.01TorrOperating range 1.7x10-3to<5x10-8Torr(2.3x10-3to<6.5x10-8mbar)Maximum forepressure Noload:0.50Torr(0.65mbar)

Fullload:0.35Torr(0.45mbar)Recommended backing pump ≥300cfm(510m3/hr)Backstreaming rate**, standard cold cap <7x10-4mg/cm2/minWarmup time 60minutesCooldown time 180minutesFluid charge 3U.S.gallons(11.3liters)Electrical requirements 3ph,50/60Hz,240/415/480VACPump power 24,000wattsCooling water requirements 4gpm(800l/hr)at60-80°F(15-26°C)Water connections ⅜in.FPTTee** For an explanation of pumping speed measurements, please see page 34.** Refer to page 32 for a description of test methods.

► Agilent HS-32


27

Diffu

sion

P

umps

DIFFUSION PUMPS

010-8

Air s

peed

(l/s

ec)

2000

10-7 10-6 10-5 10-4 10-3 10-2 10-1

40006000

800010000

1200014000160001800020000 50

45403530

25201510

50

Thro

ughp

ut (T

orr-l

/sec

)



Description Wt. kg(lbs) Part Number HS-32 Pump ASA ISOHS-32withstandard 612(1,350) 76134308 L5923308 coldcap,240VHS-32withhalobaffle,240V 612(1,350) 76134318 L5923318HS-32withstandard 612(1,350) 76134326 L5923326 coldcap,415VHS-32withhalobaffle,415V 612(1,350) 76134336 L5923336HS-32withstandard 612(1,350) 76134309 L5923309 coldcap,480VHS-32withhalobaffle,480V 612(1,350) 76134319 L5923319

Accessories Wt. kg(lbs) Part NumberWater-cooledhalobaffle 16(35) K1856332Quickcoolcoil–mustbeinstalled Factory inthefactory SpecialCenteringringforISOforeline 0.5(1.0) IC200SV flange,200KInstallationandOperationManual 699901140 (downloadfromwww.agilent.com/chem/vacuum)


Replacement Parts(sixheatersrequiredperpump)Heater*,4000W,240V/415V/ 0.5(1.0) 647332010 480VwithleadsHeater*,4000W,240V/415V/ 0.5(1.0) 647332075 480Vnoleads–usedonpumps builtbeforeMay‘90*One heater consists of 2-120V heaters, right and leftHeatercrushplate 0.5(1.0) K7246001 (replaceonewitheachnewheater)Heaterinsulator(onerequiredperpump) 0.5(1.0) 75792001Heaterclampingplate(sixrequiredperpump) 4(8) K7247001HS-32/35heaterwire,10AWG,196inches 1.0(0.4) X3900-68003 (2perheaterrequired)Replacemento-ringkitforASApumps 0.5(1.0) K0377167 (kitcontains:1inletflangeo-ring (buna45390001),1forelineflange o-ring(butyl2-443),sightglasso-ring andgasket,8fillanddraino-rings(Viton2-213)Sightglassservicekit 1.5(3.0) F6097301 (pumpsbuiltbeforeOct.‘95)Sightglassservicekit 1.5(3.0) L9223001 (pumpsbuiltafterOct.‘95)ISOinletflangeo-ring 0.5(1.0) 78536002Upper(water)thermalswitch 0.5(1.0) K9050005 (setat220°F/104°C)Lower(boiler)thermalswitch 0.5(1.0) K9050004 (setat550°F/288°C)Coldcapgasket/grommet(kitof4) 0.5(1.0) L8839301Coldcapnutandfollower(2each) 0.5(1.0) L8840301


NOTE • Inlet flange 32 in. ASA, foreline flange 6 in. ASA • Inlet flange ISO 800F (bolted), foreline flange ISO 200K (clamped) • Not recommended for use with Santovac 5

• ASA pump versions include o-rings for both inlet and foreline flanges

• ISO pump versions include inlet flange o-ring, but does not include foreline flange centering ring

PleasenotethatthisitemiscontrolledforexportbytheNuclearSuppliersGroup.Accordingly,youmayberequiredtoobtainexportlicenses,includingfromUSgovernmentauthoritiespriortoexportingthisdiffusionpumpfromtheUnitedStates.PleasecontactAgilentVacuumProducts,andtheU.S.ExportAdministrationregulationsECCN2B231forfurtherguidance.



28

42.25

(1073)

31.81

(808)

72.13

(1832)

010-8

Air s

peed

(l/s

ec)

5000

10-7 10-6 10-5 10-4 10-3 10-2 10-1

10000

15000

20000

25000

30000

35000 70

60

50

40

30

20

10

0

Thro

ughp

ut (T

orr-l

/sec

)

10-110-7 10-6 10-5 10-4 10-3 10-2



Technical SpecificationsPumping speed, operating range 28,000l/sair,35,000l/sHeandH2Pumping speed*, AVS 4.1(1963) 50,000l/sairMaximum throughput 25T-l/s(33mbarl/s)inoperatingrange,35T-l/s(45mbar-l/s)@ 0.01TorrOperating range 9x10-4to<5x10-8Torr(1.2x10-3<6.5x10-8mbar)Maximum forepressure Noload–0.55Torr(0.71mbar),FullLoad–0.40Torr(0.52mbar)Recommended backing pump ≥300cfm(510m3/hr)Backstreaming rate**, standard cold cap <5x10-4mg/cm2/minWarmup time 60minutesCooldown time 180minutesFluid charge 3U.S.gallons(11.3liters)Electrical requirements 3ph,50/60Hz,240/415/480VACPump power 24,000wattsCooling water requirements 4gpm(800l/hr)at60-80°F(15-26°C)** For an explanation of pumping speed measurements, please see page 34.**Refer to page 32 for a description of test methods.

PUMP MODELS

► Agilent NHS-35

NHS-35 Pumping Speed - Air/N2



29

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umps

DIFFUSION PUMPS

Ordering InformationDescription Voltage Weightkg(lbs) Part Number Flange Type NHS-35 Pump ASA ISONHS-35withstandardcoldcap 240V 680.0(1,550.0) F1730308 L5924308NHS-35withhalobaffle 240V 680.0(1,550.0) F1730318 L5924318NHS-35withstandardcoldcap 415V 680.0(1,550.0) F1730326 L5924326NHS-35withhalobaffle 415V 680.0(1,550.0) F1730336 L5924336NHS-35withstandardcoldcap 480V 680.0(1,550.0) F1730309 L5924309NHS-35withhalobaffle 480V 680.0(1,550.0) F1730319 L5924319

Accessories Page Weightkg(lbs) Part NumberWater-cooledhalobaffle 31 20.0(45.0) K1857335Quickcoolcoil–mustbeinstalledinthefactory,cannotshipseparately FactorySpecialCenteringringforISOforelineflange,200K 0.5(1.0) IC200SVO-ring,ISOInletflange 0.5(1.0) 78536002InstallationandOperationManual 699901140 (downloadfromwww.agilent.com/chem/vacuum)

Replacement Parts(sixheatersrequiredperpump)Heater4000W,240V/480Vwithleads 0.5(1.0) 647335010Heater4000W,240V/480Vnoleads–usedonpumpsbuiltbeforeMay‘90 0.5(1.0) 647235248Heater,4000W,200V 0.5(1.0) 647335020Heater,4000W,400V 0.5(1.0) L6383010Heater,4000W,440V 0.5(1.0) L6383011Heatshield(reusable) 0.5(1.0) L6370001Heaterclampingplate(sixrequiredperpump) 4.0(8.0) F1749001Heaterinsulator(onerequiredperpump) 0.5(1.0) L9699001HS-32/35heaterwire,10AWG,196inches(2perheaterrequired) 1.0(0.4) X3900-68003Replacemento-ringkitforASApumps(kitcontains:1inletflangeo-ring(buna78536001), 0.5(1.0) K0377169 1forelineflangeo-ring(butyl2-267),sightglasso-ringandgasket, 8fillanddraino-rings(Viton2-213)Sightglassservicekit(pumpsbuiltbeforeOct.’95) 1.5(3.0) F6097301Upper(water)thermalswitch(setat200°F/93°C) 0.5(1.0) K9050005Lower(boiler)thermalswitch(setat600°F/316°C) 0.5(1.0) K9050006Coldcapgasket/grommet(kitof4) 0.5(1.0) L8839301Coldcapnutandfollower(2each) 0.5(1.0) L8840301NOTE • Inlet flange 35 in. ASA, foreline flange 6 in. ASA • Inlet flange ISO 1000F (bolted), foreline flange ISO 200K (clamped) • Not recommended for use with Santovac 5 • ASA pump versions include o-rings for both inlet and foreline flanges • ISO pump versions include inlet flange o-ring, but does not include foreline flange centering ring

PleasenotethatthisitemiscontrolledforexportbytheNuclearSuppliersGroup.Accordingly,youmayberequiredtoobtainexportlicenses,includingfromUSgovernmentauthoritiespriortoexportingthisdiffusionpumpfromtheUnitedStates.PleasecontactAgilentVacuumProducts,andtheU.S.ExportAdministrationregulationsECCN2B231forfurtherguidance.

30

FLUIDS

Ordering InformationDescription Diffusion Pump Weight kg(lbs) Part Number Exact Charge

NEOVAC SY1liter/1,000cc VHS-10,VHS-400 3.0(1.4) K6948301U.S.gallon(3.8liters) 10.6(4.8) K69483055U.S.gallons(18.9liters) 53.0(23.9) K6948315

Santovac 540cc 1.0(0.5) 69540500165cc 2.0(0.9) 695405002500cc VHS-6,VHS-250 2.5(1.1) 695405005

Invoil 704 PleaseaskAgilentfordetails

NEOVAC SY Invoil 704 SANTOVAC 5*Chemicaldescription Synthetic Single-component Mixed5-ring hydrocarbon silicone polyphenyletherChemicalcomposition Mono-N Tetramethyltetraphenyl Mixed5-ring alkyldiphenylether trisiloxane polyphenylEtherUltimatepressure Untrapped(Torr) Low10-8range 10-7to10-8range 10-10

Trapped(Torr) 1x10-11range to10-11range –Vaporpressureat25°C(Torr) 1x10-8 2x10-8 1x10-9at20°CViscosity(cst)at25°C 25at40°C 38 2400Averagemolecularweight 405 484 446Boilingtemperature(°C)at0.5Torr 220at0.8Torr 210 275Flashpoint 230 221 288Ultimatepressure Verygood Verygood ExcellentThermalstability Good Excellent VerygoodOxidationresistance Good Excellent VerygoodSystemcleanliness Verygood Verygood Excellent*Santovac 5 is the only recommended fluid for leak detectors.

NEOVAC SYisahighquality,lowcostsyntheticorganiccompound(alkyldiphenylether).Withitslowvaporpressure,itwillachievebasepressuresinthelow10-8Torrrangeuntrappedandwillnotproduceinorganicdepositswhichcancauseelectrostaticchargebuilduponelectrodesofsensitiveinstruments.

Invoil 704isasiliconeoilwithlowvaporpressureandgreatthermalstability,makingitdesirableinprocessessuchasvacuumcoating,metallurgicalwork,andvariousotherapplications.Itofferssuperiorvaporpressurecapabilities

andquickpumpdowncycles.Withitslowvaporpressure,itcombinesverygoodpumpingcharacteristicswithlowBackstreamingRates.

Santovac 5isafive-ringpolyphenyletherforuseinultrahighvacuumapplications.Withultralowvaporpressureandbackstreamingrates,thisfluidisverycleanandofteneliminatestheneedfortrapsandbaffles.Ultimatepressuresinthe10-10Torrrangecanbeachievedandwillnotproduceinorganicdepositswhichcancauseelectrostaticchargebuilduponelectrodesofsensitiveinstruments.

Agilent offers NeoVac SY, Santovac 5 and Invoil 704 diffusion pump fluids in a variety of container sizes for your convenience.

31

Diffu

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P

umps

DIFFUSION PUMPSBAFFLES

Technical SpecificationsSpeedwithExtendedColdCap ≈80%ofpumpspeedMaterials Nickel-platedcopperCooling Conduction(nowater)

Ordering InformationDescription Weight Part kg(lbs) NumberVHS-4 0.5(1.0) F6898301VHS-6 0.5(1.0) F6455001VHS-10 0.9(2.0) L8917301

TheExtendedColdCapisanoptionthatfitsinsidetheVHS-4,VHS-6,andVHS-10pumpsinplaceofthestandardcoldcap.Itstopsbackstreamingaseffectivelyasanopticallydensebaffle,yetitretains80%ofthepump’sspeed.ResidualbackstreamingissolowthatitcannotbemeasuredbytheAmericanVacuumSociety’sstandardcollectionmethod.

Technical SpecificationsNetspeedwithHaloBaffle Approximately60%of

pumpspeed*Backstreamingreduction Approximately90%*Materials Nickel-platedcopper

(16in.,20in.) Nickel-platedmildsteel

(32in.,35in.)Cooling:recommended Inserieswithdiffusionpumps;Waterflow seespecificdiffusionpump

technicalspecsHS16–NHS-35

Ordering InformationBaffle Size Weight Part kg(lbs) Number16in. 9.0(20.0) K014331620in. 11.0(25.0) K185532032in. 16.0(35.0) K185633235in. 20.0(45.0) K1857335* Values are estimates. Actual speed and backstreaming rate will

vary depending on the application conditions.

Agilent’sHaloBafflesprovidenearlytwicethespeedatthepumpinletasthatachievedwithconventionalchevronbaffles,whileaddingnoheighttothesystem.Thesewater-cooledbafflesareveryeconomicalcomparedtootheropaquechevronbaffles.

► Extended Cold Caps for VHS-4, -6, and -10 Diffusion Pumps

► Halo Baffles for Large Diffusion Pumps for HS-16, -20, -32 and NHS-35 Diffusion Pumps

32

TECHNICAL NOTES

DiffusionpumpswerefirstconceivedandconstructedbyW.Gaede(1915-Germany)andI.Langmuir(1916-U.S.A).Theyoperateontheprincipleoftransferringmomentumfromhighvelocityvapormoleculestothegasmoleculesthataretobemovedoutofthesystem.Thevapormoleculesareformedbyheatingasuitablecondensablefluid.Theearlypumpsusedmercuryforthispurpose.

Inthelate1920s,C.R.Burch(England)andK.C.Hickman(U.S.A.)foundthatcertainhighmolecularweightoilshavinghighboilingpointsandlowvaporpressurescouldbeusedaspumpingfluids.Theseoilswereusefulbecausetheyremainedinthepumpindefinitelyandallowedlowerpressurestobeattainedwithouttheuseofacoldtrap(seesectiononBafflesandTraps).Today,withtheexceptionofafewisolatedapplicationslikesomeanalyticalinstruments,alldiffusionpumpsusesomeformofoil.Foradditionalinformationinthisarea,seethediscussiononpumpingfluidsbelow.

Asindustrialandscientificrequirementsforrarefiedatmospheresincreased,researchanddevelopmentintothenatureandproductionofhighvacuumincreased.Bytheearly1940s,awell-developedvacuumtechnologyexistedandwasintensifiedbothduringWorldWarllandbythespaceeffortofthe1960s.Engineeringhascontinuedinthevacuumfield,andin1965Agilent’sM.H.Hablanian,etal.madeasignificantcontributiontodiffusionpumpdesignthatmarkedlyincreasedpumpingspeeds.

ApplicationsDuetoitssimplicity,highperformance,andlowinitialcost,thediffusionpumpremainsaprimaryindustrialhighvacuumpumpingmechanism.Applicationsforthistypeofpumparefoundinsuchdiverseareasas: 1.Analyticalinstruments 2.Coating,functional 3.Coating,ornamental 4.Electrontubemanufacture 5.Metallurgy 6.Optics 7.Outerspacesimulation 8.Particleaccelerators 9.Petrochemicals10.Pharmaceuticals11.R&Dlaboratories12.SemiconductormanufactureUsedincombinationwiththeproperchoiceofmotivefluids,traps,baffles,andvalves,diffusionpumpscanbeusedinawidevarietyofapplicationsandoverpressurerangesfrom1x10-3Torrto2x10-11Torr.

Basic Performance Factors1.Pumpingspeedisvolumeperunittime.Itisgenerally

specifiedinliters/secondandisanimportantparameterindeterminingtheultimatepressureofasystem.

ThisisexpressedbytherelationshipQ=PS

Where: QisthesystemgasloadinTorr-liters/second

PistheattainablepressureinTorrSistheeffectivepumpspeedatthesystem“Q”isthetotalleakageofthesystemwhichincludesvaporsgivenoffbydirtandoutgassingofinternalsurfacesaswellasholestotheoutsideworld.Ultimatepressureisalsoaffectedbysuchfactorsasthecompressionratioforlightgasesandthenatureofthepumpingfluid.

2.Maximum throughput isthepump’smaximumgasmasstransfercapability–pressurexvolumeperunittime.ItisgenerallyspecifiedinTorr-liters/secondormbarl/s.

3.Tolerable forepressureisthemaximumallowablepressureintheforeline.Itismaintainedatorbelowthisvaluebyasuitably-sizedmechanicalforeline(backing)pump.Ifthispressureincreasesabovethatspecifiedforagivenpump,gaswilldiffusebackthroughthepumpandpumpingwillstop.Itshouldbenotedthatthesizeofthismechanicalpumpcanaffectthemaximumthroughputvalue.

4.Backstreaming rateistherateatwhichthepumpingfluidvaporleavestheinletopeningofthepump,movingbackinthedirectionofthesystembeingpumped.Itismeasuredinmilligramspercm2perunittimeandwillvarywiththetypeofmotivefluidemployed.

OperationDiffusionpumpsarevaporjetpumpsthatworkonthebasisofmomentumtransferfromaheavyhighspeedvapormoleculetoagasmolecule.Thisresultsinthegasmoleculesbeingmovedthroughthepump.

InFigure1,thebottomofthepumpcontainsanelectricheaterthatisusedtoproducethevaporbyheatingthepumping(motive)fluidtoitsboilingpointatreducedpressure.

Figure 1 Typical Cross-sectional View of a Diffusion Pump

33

Diffu

sion

P

umps

DIFFUSION PUMPSThismeansthatbeforethepumpisstarted,itmustbe“roughpumped”downtoandheldatanacceptablepressure,typically10-1Torr.(Forinformationonroughpumping,seesectiononPrimaryPumps.)Todootherwisewillresultinnopumpingactionandpossibledamagetothepumpingfluids.Onceboilingofthefluidhasbegun,thevaporisforcedupthecentralcolumnsofthejetassembly.Itthenexitsateachdownward-directedjetintheformofamolecularcurtainthatimpactsthewater-cooledpumpbody.Here,thevaporcondensesandrunsbackdowntotheboiler.Thisrefluxingactioncontinuesaslongasproperheatandforepressurearemaintained.

Asgasmoleculesfromthesystemrandomlyenterthepump(molecularflowconditions),theyencounterthetopjet.Someofthemarecorrectlyimpactedanddrivenontothenextjet.Subsequently,theyreachtheforelinewheretheyareexhaustedtotheatmospherebythemechanicalbackingpump.

Thediffusionpumpissimilarincharactertoothercompressionpumpsinthatitdevelopsarelativelyhighexhaustpressurecomparedtotheinletpressure.Thiscompressionratioforaninletpressureof2x10-7Torrandaforelinepressureof2x10-1wouldbetenmilliontooneformostgases.Figure2showshowthepumpingspeedvarieswithpressure.Notethatthespeedremainsconstantfromthe10-3TorrscaletotheX-10Torrscaleandthenfallsoffasaresultofthecompressionratioforhydrogenandheliumplusthevaporpressurecontributionofthepumpingfluid.Inthesamewaythatthepumpmustberoughpumpedbeforestarting,somustthesystemtobeevacuatedbyroughpumpingpriortoexposuretothepump.Exposingahotpumptoarushofairatatmosphericpressurecouldbecatastrophicfortheequipmentandpossiblyexplosive,dependinguponthe

pumpfluidbeingused.Forfurtherinformationinthisarea,seethediscussiononpumpingfluids,below.

Design FeaturesDesignfeaturesuniquetoAgilentdiffusionpumpsprovidepositivebenefitstothecustomer,suchas:

1.Agilentoildiffusionpumpsincorporateanejectorstageaswellasthefullfractionationjets.Thisfeatureassurestheuserofconstantlypurifiedpumpingfluidandthecapabilityofmaintaininglowpressures.

2.Agilentoildiffusionpumpsincorporateinsulatedjetdripshieldswhichpreventre-boilingofoildropletsoutsidethejetassembly.Thisfeatureassurestheuserofthelowestbackstreamingratesattainable.

3.Agilentwatercoolingcoilsareattachedbyaproprietaryweld/bracetechnique.Thisspecialtechniquemeansexcellentthermalcontactandnochanceforcoilsto“melt”awayfromthepumpbodyincasesofaccidentaloverheating.

4.Agilentpumpsincorporateawater-cooledcoldcapthatreduces98percentofthebackstreamingcommontomostdiffusionpumpsandtheuserisassuredofacleanersystem.

5.Agilentwater-cooledpumpsincorporatethequickcoolboilercoils,allowingfastershutdownofthesystemwithnodamagetotheoil.

6.AgilentpumpsusestandardASAflanges.Thisfeaturepermitswideflexibilityformattingwithsystemsandotherhardware.

7.Agilent(4-inchandlarger)pumpshaveathermalprotectionswitchasastandardfeature.Thisdevicepreventsdamagetothepumpandsurroundingsduetooverheating.

Pumping FluidsInanoildiffusionpump,highspeedheatedoilvaporprovidesthekineticenergythatmovesgasmoleculestotheforelineandpreventstheirback-migration.Theseoilsmaybederivedfromapetroleumbasebutmoretypicallyaresynthesizedfromphthalates,sebacates,phenylgroups,orsiloxanes.

Tobeaneffectivepumpingfluid,thecompoundmusthavearelativelyhighmolecularweightandalowvaporpressureatelevatedtemperatures.Otherdesirablepropertiesareinertnessandstabilityinordertoresistchemicalreactionanddisintegrationintoundesirablefractions.

PhenyletherssuchasNeovac-SYandSantovac-5arefairlyresistanttooxidationandareusedsuccessfullyaroundelectronicdevices.Theseoilspolymerizeintoaconductingfilmwhenbombardedwithelectronsandthusdonotpromotestaticchargebuild-up.Inaddition,theyarequitesolubleand“cleanup”easily.Neovac-SYhastheadvantageofeconomywhileSantovac-5ismoredurableandhasalowervaporpressure.

Constant SpeedConstant

Q

MechanicalPumpEffect

P/P

Critical Point

Pum

ping

Spe

ed (A

ir)

-10-1 Torr-10-3-10-10

Overload

Typicalplotofdiffusionpumpperformance.Fourregionsareevident:1)Effectofthepressureratiolimit;2)Normaloperatingrangewithconstantspeed;3)Throughputlimitedcondition;4)Effectofbackingpump.

Figure 2 Inlet Pressure

34

TECHNICAL NOTES

Foradditionaloxidationresistance,manyapplicationslendthemselvestotheuseofsiliconefluids.Thesearephenylsiloxanecompoundsthatpolymerizeasanon-conductingfilmthatcanallowstaticchargebuild-upandaredifficulttocleanup.Therearemanysiliconefluidsonthemarket,soAgilentrecommendsusingthoseequivalenttoInvoil704(seepage30)ortheirvariants,dependingonapplication.Anotherextremelystablefluidunderreactiveconditionsisthefluorinatedpolyphenylether(Fomblin®orKrytox).Thisoiliswidelyusedinmechanicaloil-sealedpumpswherelargeamountsofoxygenarepumped.Itisalsosuitableasadiffusionpumpfluidwherelargequantitiesofoxygenorotherreactivegasesmaybeencountered.

Speed MeasurementsNote: The speed values in this catalog have been measured

according to ISO Standard 1608/1. They differ from the values published in previous catalog editions strictly due to the change in testing methods. Thedesignandperformanceofthepumpshavenotchangedinanyway–onlythespeedtestmethod.

For reference, the speed values from the previous catalog editions are included in the technical specifications table for each pump. The data is labeled “Pumping Speed”, AVS 4.1 (1963).

The pressure gage mounted in the test dome is located at a distance of 1/2 the diameter of the pump from the inlet plane, versus 1/4 the diameter in previous tests. Also, total pressure gages were used to measure the pressure and calculate speed, versus partial pressure gages.

Combined, these two changes in test method result in a measured speed approximately 40% lower than previously published values. The changes in test method do not affect maximum throughput measurements.

Pumpingspeedismeasuredbyintroducingaknown,steadystateflowofgasintoameasuringdomeofspecifiedgeometryandmeasuringtheresultingpressureestablishedinthedome.Figure1showstheexperimentalsetupusedbyAgilentasrecommendedbytheAmericanVacuumSociety(Standard4.1).SpeedisdeterminedbytheAVSStandardas:

S=Q/(P–P0),

whereQistheflowrate(throughput)andP0istheultimatepressurepriortotheexperiment.AlldiffusionpumpcurvesshowninthecatalogarebasedontheuseofDC704diffusionpumpfluidandthestandardcoldcap(unlessotherwisenoted).Thespeedcurvesarecreatedbycalculatingthespeedatincreasinglevelsofgasthroughput,allowingtimebetweenreadingstoensuresteadystateconditionsarereached.

Diffusionpumpsexhibitdifferentspeedsfordifferentgases.Thus,thespeedofeachgasisobtainedbydividingthethroughputofthegasbythepartialpressureofthesamegasinthedome.Unlessotherwisenoted,thespeedsshowninthiscatalogareforair.

Measuringthespeedofadiffusionpumpinstalledinavacuumsystemoftengivesdifferentresultssincethegeometry,surfacearea,constructionmaterials,andmostimportantly,pressuremeasurementlocationsdifferfromthemeasuringdome.

Backstreaming MeasurementsPrimarybackstreamingcanbemeasuredbyrelativelysimplemeansforpumpswithoutbafflesortraps.AVSStandard4.5(JournalofVacuumScienceandTechnology,Volume8,Number5.)recommendsthetestdomeconfigurationshowninFigure2.ThebackstreamingratespublishedinAgilent’scatalogaremeasuredusingthistechnique.Anymoleculeswhichcrossthepumpinletintheupwarddirectionandcondenseinthedomemaybesaidtobebackstreaming.Thecondensedpumpingfluidcollectsinthetrougharoundtheperipheryofthedomeanddrainsintoameasuringtube.Usually,ittakesseveraldaystocollectsufficientfluidforsatisfactorymeasurements.Regularvolumetricmeasurementsaretakenandrecordedonavolumeversustimegraphuntiltherateisobservedtobesteady(±10%)foratleast72hours.ThebackstreamingrateistheaverageslopeoftheVolume-Timecurveinthe72hourtimeperiod.Notethatthistestwillignore“spikes”inthebackstreamingrate,whichmayoccurduringstartup,sinceonlythevolumecollectedduringthesteady-state,72-hour

Figure 1

35

Diffu

sion

P

umps

DIFFUSION PUMPSperiodisconsidered.AllbackstreamingtestswereperfomedusingDC-704pumpingfluid(nolongeravailable).

Themeasuredbackstreamingrateisverydependentonthetestmethodused.Ifanymethodotherthanthedomemethoddescribedaboveisused,theresultscandiffersignificantlyfrompublishedvalues.Notealsothatthereportedbackstreamingvaluesarevalidforthenormaloperatingrangeofthepump,atapressurewellbelowthepointatwhichthetopjetstartstobreakdown(i.e.belowthe“knee”ofthespeedcurve,wherethespeedisnolongerconstantwithpressure).Abovethiscriticalpressurethebackstreamingratemayrisemarkedly.

Backstreamingmeasurementsabovethebafflecannotbemadewiththestandardtestapparatus.Theratesaresolowthatthecollectingsurfacesmustberefrigeratedtopreventre-evaporation,andthecollectionsurfacemustbedesignedtocollectsmalleramountsoffluid.

Using Baffles to Reduce BackstreamingIfthevacuumsystemhasintolerancetobackstreaming,abaffleortrapshouldbeconsidered.Toooftenasystemdesignerwillforegotheuseofbafflestoreducesystemcost,onlytofindthenormalamountofbackstreamingfromthediffusionpumpsistoohighfortheapplication.Thisisusuallythecaseforhighqualitycoatingapplications.Thechoiceofbaffletypeisatrade-offbetweenbackstreaminglevel,net

pumpingspeed,size,andcost.Thedesignercanchooseawater-cooledhalobaffle,water-cooledopticallydensebaffle,oracryotrap.Adiffusionpumpcanbeorderedwithacoldcaporahalobaffle(whichhasanintegralcoldcap).Ifanexternalbaffleistobeused,thediffusionpumpistypicallyorderedwithacoldcap.

Awater-cooledhalobaffleisdesignedtointerceptamajorityoftheprimarybackstreamingwhichescapesthecoldcap.Acooledring,orhalo,isstrategicallyplacedwheremostofthebackstreamingoccurs.Therateisreducedbyapproximately90%withacorrespondingreductioninspeedofroughly40%.Theactualreductioninbackstreamingandspeeddependsonthetypeofpumpandtheapplicationconditions.Awater-cooled,opticallytightbaffleisdesignedtointercept100%oftheprimarybackstreaming,sowhatremainsissecondarybackstreaming.Thetemperatureofthebafflesurface,ratherthanthebafflegeometry,determinesthesecondarybackstreamingrate.Thusthechoiceofbafflebecomesatrade-offbetweensize(height),conductance,andcost.

Acryotrap,orliquidnitrogentrap,hasaliquidnitrogenreservoirandvariousbafflingsurfaces.Thereservoirisinsulatedfromtheenvironmentbyanevacuatedspace.TheLN2boilsofftoatmospherethroughaventport.SinceLN2boilsat–196°C,thetrap’sinternalsurfacesareextremelycold.Insystemswithliquidnitrogentraps,thebackstreaminglevelcanbecontrolledatsuchalowlevelthatcontaminantsfromsourcesotherthanthediffusionpumpwillpredominate.

Estimating the Effect a Baffle Has on the Speed of the PumpThedegreetowhichabafflewillreducetheeffectivepumpingspeedofadiffusionpumpdependsonitsconductance,whichisafunctionofitsgeometry.ManufacturerseitherpublishconductancevaluesinL/sorprovideanestimateoftheretainedpumpingspeed(e.g.“Retains50%ofpumpingspeed”).Whenaconductancevalueforthebaffle,Cbaffle,ispublished,anestimateofftheeffectivepumpingspeed,Seff,isgivenby:

Seff=(Cbaffle*Spump)/(Cbaffle+Spump)

Figure 2

agilent diffusion pumps - ideal vac the pump. as a result, agilent diffusion pumps offer you the...

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