Varian NHS-35, Instruction Manual, Page: 21 / 49

1-1
SECTION I
INSTALLATION
1-1 GENERAL
Upon receipt, inspect the container for evidence of damage in shipment. Do not discard any evidence of
rough handling. Factory packing provides for maximum protection during shipment. However, the pump
should be inspected immediately and any damage should be reported to the carrier without delay.
Before unpacking and installing the pump, the user should thoroughly familiarize himself wiith the
contents of this instruction manual, particularly the physical and operating specifications listed in the
following paragraphs, in order to gain a better understanding of the operating principles, limitations,
correct application of the diffusion pump, the hazards involved, and what to do and what not to do in
order to avoid these hazards.
1-2 OPERATING SPECIFICATIONS
Model Part Number
NHS-35 Diffusion Pump 240 V 480 V 380/415 V 400 V 440 V
with ASA flanges & standard cold cap F1730308 F1730309 F1730326 F1730362 F1730364
with ASA flanges and halo baffle F1730318 F1730319 F1730336 F1730363 F1730365
with ISO flanges & standard cold cap L5924308 L5924309 L5924326 – –
with ISO flanges and halo baffle L5924318 L5924319 L5924336 – –
Optimum Operating Range 6 x 10
-4
torr to < 5 x 10
-8
torr
(8 x 10
-2
Pa to < 7 x 10
-6
Pa)
(8 x 10
-4
mbar to < 7 x 10
-8
mbar)
Maximum Pumping Speed 50,000 liters/sec for air
(See Figure 1-1) 62,500 liters/sec for helium
Maximum Throughput 35 torr-liters/sec at 10
-2
torr
4655 Pa - liters/sec @ 1.33 Pa
46.5 mbars - liters/sec @ 0.013 mbar
Maximum Forepressure No Load – 0.55 torr (73.2 Pa) (0.73 mbar)
Full Load – 0.40 torr (53.2 Pa) (0.53 mbar)
Backstreaming Rate at Pump Inlet 0.0005 mg/cm
2
/min (with cold cap)
Power Required (approximately) 24 KW, 240/380/415/440/480V, 50/60 Hz, 3-phase
Warmup Time 60 hour
Cooldown Time (using quick cool) 180 minutes (60 minutes)
Fluid Charge 3 gallons
Cooling Water Requirements 4 gpm at 60°F to 80°F inlet temperatures
Backing Pump Size Recommended 300 cfm for optimum throughput