Available in 4-inch, 6-inch, 250-mm, 10-inch, and 400-mm sizes, the VHS series pumps are the fastest and cleanest diffusion pumps of their size available today. The VHS series patented Bulge Contour doubles gas capture and maintains lower pressure. All VHS series pumps have sight glass/fill and drain assemblies for continuous monitoring and easy maintenance of pump fluid. Finned boilers increase surface area, prolonging pumping fluid life. Full thermal protection and quick-cool coils are also standard. The 4-inch, 6-inch, and 10-inch pumps can be ordered with ASA or ISO flanges, standard or extended cold caps, and a variety of voltages.
Technical Specifications
| Pumping Speed, Operating Range Pumping Speed, AVS 4.1 (1963) | 750 l/s air, 940 l/s He/H2 1,200 l/s Air |
| Maximum Throughput | 1.5 T-l/s (2.0 mbar-l/s) in operating range, 2.5 T-l/s (3.2 mbar-l/s) @ 0.01 torr |
| Operating Range | 2 x 10-3 to <5 x 10-9 torr (2.7 x 10-3 to <6.5 x 10-9 mbar) |
| Maximum Forepressure | No Load: 0.65 torr (0.86 mbar) Full Load: 0.55 torr (0.73 mbar) |
| Recommended Backing Pump | ≥10 cfm (17 m3/hr) |
| Backstreaming Rate, Standard Cold Cap | <5 x 10-4 mg/cm2/min |
| Warmup Time | 10 minutes |
| Cooldown Time | 10 minutes (with quick cool coil) |
| Fluid Charge | 300 cc |
| Electrical Requirements | 1 ph, 50/60 Hz, 120/208/240 VAC |
| Pump Power | 1450 watts |
| Cooling Water Requirements | 0.15 gpm (30 l/hr) at 60-80°F (15-26°C) |
| Water Connections | 1⁄8 in. FPT Tee |
Speed Curve Graph
Pumping Speed/Standard Cold Cap Pumping speed/Extended Cold Cap Throughput
Outline Drawing
| Description | Weight kg (lbs) | Part Number |
| VHS-4 Pump with standard cold cap | ||
| 120 V with ASA flanges | 25.0 (55.0) | 86460301 |
| 120 V with ISO flanges | 25.0 (55.0) | L6256301 |
| 120 V with ConFlat Flanges | 25.0 (55.0) | L6188301 |
| 208 V with ASA flanges | 25.0 (55.0) | 86460306 |
| 208 V with ISO flanges | 25.0 (55.0) | L6256306 |
| 208 V with ConFlat Flanges | 25.0 (55.0) | L6188306 |
| 240 V with ASA flanges | 25.0 (55.0) | 86460302 |
| 240 V with ISO flanges | 25.0 (55.0) | L6256302 |
| 240 V with ConFlat Flanges | 25.0 (55.0) | L6188302 |
| VHS-4 Pump with extended cold cap | ||
| 120 V with ASA flanges | 25.0 (55.0) | 86460311 |
| 120 V with ISO flanges | 25.0 (55.0) | L6256311 |
| 120 V with ConFlat Flanges | 25.0 (55.0) | L6188311 |
| 208 V with ASA flanges | 25.0 (55.0) | 86460316 |
| 208 V with ISO flanges | 25.0 (55.0) | L6256316 |
| 208 V with ConFlat Flanges | 25.0 (55.0) | L6188316 |
| 240 V with ASA flanges | 25.0 (55.0) | 86460312 |
| 240 V with ISO flanges | 25.0 (55.0) | L6256312 |
| 240 V with ConFlat Flanges | 25.0 (55.0) | L6188312 |
| Accessories | ||
| 334 water-cooled baffle with ASA flanges | 4.5 (10.0) | F8286304 |
| 334 water-cooled baffle with ISO flanges | 4.5 (10.0) | F8286305 |
| 334 water-cooled baffle with ConFlat Flanges | 4.5 (10.0) | F8286306 |
| Centering ring for ISO inlet flange, 160K | 0.5 (1.0) | IC160SV |
| Centering ring for ISO foreline flange, KF40 | 0.2 (0.5) | KC40SV |
| Santovac 5 diffusion pump fluid, 500 cc | 1.1 (2.5) | 695405005 |
| DC-702 diffusion pump fluid, 500 cc | 1.4 (3.0) | 695472005 |
| DC-704 diffusion pump fluid, 500 cc | 1.4 (3.0) | 695474005 |
| DC-705 diffusion pump fluid, 500 cc | 1.4 (3.0) | 695475005 |
| Instruction manual | 699901021 | |
| Replacement Parts | ||
| Heater, 120 V 1450 W (one required per pump) | 0.5 (1.0) | 647304205 |
| Heater, 208 V 1450 W (one required per pump) | 0.5 (1.0) | 647304210 |
| Heater, 240 V 1450 W (one required per pump) | 0.5 (1.0) | 647304250 |
| Heater clamp (one required per pump) | 1.0 (2.0) | 88164301 |
| Replacement nickel heater wire | 0.5 (1.0) | 65617910 |
| O-ring kit, 3 for inlet (butyl, 2-258), 10 for fill and drain (Viton, 2-113) | 0.5 (1.0) | K0377183 |
| Thermal switch (set at 300 °F/147 °C) | 0.5 (1.0) | 642906025 |
| Extended cold cap | 0.5 (1.0) | F6898301 |
| Sight-glass repair kit | L8908301 | |
| Basic sight-glass cooling kit | R1523301 | |
| Extended sight-glass cooling kit | R1208301 | |
