Varian Diffusion Pumps Overview
Features and Benefits
Varian 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, Varian Diffusion Pumps
offer you the lowest cost of ownership available for many
high vacuum-pumping applications.
Options to Address Your Needs
Many applications have unique requirements.
Varian 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.
Easy to Maintain
Maintaining 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.
Fully Optimized Jet
Using our long and varied experience Varian designs and produces vapor jets that deliver the highest
throughput, pressure stability, and tolerable foreline pressure available, while reducing backstreaming
to a minimum.
Built for Production Volumes
Our 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 Design
Through optimized boiler design, Varian 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.
Low Cost of Ownership
By providing the highest throughput available per unit of power, reduced cooling water requirements,
and rugged, durable stainless steel construction, Varian delivers large volume pumping at the lowest total
cost to you.
World-class Service, Training and Support
Varian'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
Vapor Diffusion Pumps
- Vacuum Furnaces
Vacuum Furnace applications require pumps that have the
ability to achieve and maintain low base pressures and the
ability to handle. The full fractioning design of the Varian
diffusion pumps allows vaporized fluid to be fractionated in
the boiler and jet assembly. Contamination and
decomposition products are pumped away and only the
purist fluid reaches the top jet, assuring highest speed and
In web and roll coating systems, Varian diffusion pumps
have the ability to pump high gas loads making them the
perfect choice for continuous production applications.
- Large Area Coating / Thin Film Deposition
Due 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, Varian diffusion pumps are
the best choice for developmental and production systems.
- Molecular Beams
The 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 Varian 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.
Pumps are equipped with full thermal protection.
Application Notes for Diffusion Pumps
As the worldwide diffusion pump market leader, Varian
produces the most comprehensive family of pumps, ranging
from 2 in. to 35 in. in diameter, and is the only broad-line,
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 Varian Diffusion Pumps include:
- High pumping speeds
- High throughput
- High forepressure tolerance
- Low ultimate pressure
- Excellent backstreaming characteristics
- Long-term reliability