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Installation
1-2
1-3 PHYSICAL SPECIFICATIONS (See Figure 1-2)
Flange dimensions (inches):
Figure 1-1. Speed and Throughput Curves – HS-20 Diffusion Pump
ASA ISO 630k ISO 160k
Inlet Foreline Inlet Foreline
OD 27.50 9.0 27.17 7.09
ID 21.25 5.06 21.25 5.06
Thickness 1.12 0.75 0.78 0.47
Bolt Circle 25.0 7.5
No. of Holes 20.0 8.0
Size of Holes 1.25 0.75
Orientation Straddle center line
Gasket Groove ID 21.625 5.31
wide 0.48 0.375
deep 0.25 0.09
Height 48 inches; allow additional
8 inches (min) for heater removal
Jet Assembly 5-stage, Self-aligning, fractionat-
ing design with four diffusion
stages and one ejector stage
Foreline Stacked disk and ring
Baffle
Cold Cap Water-cooled
Water
1
⁄4 FPT body and foreline
Connections
3
⁄8 quick cool coils
Thermal Upper set at 185°F (29°C)
Switches Lower set at 390°F (93°C)
Materials Body: Mild steel
Flanges: Mild steel
Jet Assembly: Aluminum
Foreline Baffle: Stainless Steel
Cooling Coils: Copper
Quick Cool Coils: Stainless Steel
Cold Cap: Copper (Nickel-plated)
Weight 500 pounds
Shipping 580 pounds
Weight
Requires NW-630
Centering Ring (not
included with pump)
Requires NW-160
Centering Ring (not
included with pump)