The Agilent Varian VHS-250 has been designed to fill a special need in applications where high pumping speeds are required and space limitations demand a compact pump. The VHS-250 pump is a rugged, general-purpose unit with an operating range of 1.2 x 10-3 to <5 x 10-9 Torr. The Agilent Varian VHS-250 is ideal for applications requiring fast cycling because of its high pumping speed (maximum rated at 3700 l/s) air combined with high forepressure tolerance (0.65 Torr with no-load and 0.55 Torr when at full gas load). Backstreaming rate of the unit is 1x10-4 mg/cm²/ min, without the use of any cooled cold cap.

This Agilent Varian VHS-250 Diffusion Pump Includes:

• ISO 250F Inlet Flange (13.25 Inch OD Flange, 12 Smooth Bolt Holes, 0.5" Diameter Holes)
• 1 1/2 inch ASA Outlet Foreline Flange (5 Inch OD)
• Standard Cold Cap
• Recommended Backing/Roughing Pump: 17CFM
• 3700 l/s Maximum Pumping Speed Air
• 120 VAC @ 2200 Watt Heater
• Designed To Be Used With Santovac 5 Diffusion Pump Oil

Diffusion pumps use a high-speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the outlet. The oil diffusion pump is operated with an oil that has low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than possible by use of positive displacement pumps alone. The Agilent Varian VHS-250 can pump down to pressures of <5x10-9 Torr. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump, roughing pump is typically used to maintain an outlet pressure around 1 mTorr.

These Agilent Varian Diffusion Pumps are very reliable, simple in design and operate with no noise or vibration. Diffusion pumps are still the most economical means for creating high-vacuum pressures. Diffusion pumps also tolerate operating conditions such as excess particles and reactive gases that would destroy other types of high-vacuum pumps. They can be ordered with a 1-phase 120, 208, 240 VAC heater harness and with standard or extended cold cap. We stock and sell Santovac 5 diffusion pump fluids for this pump. Please see below in our “Related” section for additional accessories that may benefit your vacuum applications and maintenance needs. We offer a large variety of vacuum greases, oils, vacuum fittings, hoses, vacuum gauges, sensors/transducers, parts and accessories sold separately on this website.

These Agilent Varian VHS-250 diffusion pumps have ISO 250F inlet flange, operate on 1-phase 120 VAC, standard cold cap and has Agilent Varian part number K0543301. The Agilent Varian VHS-250 diffusion pump user's instruction manuals can be downloaded in PDF format below. These are typical stock items that often ship same day as order is placed.