Pump Installation; Control Unit Connection; Bakeout - Varian 919-0520 Manuel D'instructions

Pump Installation

To install the pump into the system proceed as
follows:
1. During installation, keep the pump and
system clean. Avoid touching surfaces which
will ultimately be under vacuum. When the
VacIon pump is open to the atmosphere, take
care to avoid introducing foreign particles, oil,
solder flux, or any volatile substances. Before
attaching the pump,
thoroughly. Chemical cleaning is the most
complete cleaning method for the vacuum
system; however, do not attempt it when
pockets and crevices exist that will prevent
thorough rinsing. Degreasing with an acetone
or methanol followed by water-rinsing is
usually sufficient.
2. To achieve maximum
connect the pump to the system with a tube
that has the shortest length and the largest
diameter possible.
3. For ultrahigh vacuum work, joints should be
tungsten inert gas welded, hydrogen brazed,
or vacuum brazed. Do not use flux in making
joints for ultrahigh vacuum.
4. Gaskets in the system should be of soft metal
such as annealed copper, aluminum, or gold.
5. After the pump is sealed in place, leak-check
the entire system.
6. Assemble the magnet to the pump.

CONTROL UNIT CONNECTION

WARNING!
The high voltage present in the high voltage cable
which connects the control unit to the ion pump,
can cause severe injury or death. Before mounting
the high voltage connector of the cable on the
pump high voltage
removing it, be sure the main power is removed
from the control unit.
WARNING!
To avoid injury, never connect the high voltage to
the pump before it is installed into the system and
all the inlet flanges are properly connected or
blanked off.
clean the system
pumping speed,
feedthrough, or before
Connect the control unit to the ion pump with the
coaxial high voltage cable assembly as follows:
1. Push the female end of the cable connector
over the high voltage feedthrough.
2. Push the male end of the cable connector into
the socket on the control unit rear panel. (Refer
to the control unit instruction manual).
Before removing the high voltage connector of the
cable from the control unit, be sure the main power
is removed from the control unit. Wait at least 10
seconds after removing the main power from the
control unit, to allow capacitors to discharge
completely.
To disconnect the coaxial high voltage cable from
the controller, slide the safety locking sleeve (very
little sleeve travel is required) from the control unit
and at the same time pull on the male end of the
cable connector to remove it from the socket on
the control unit.

BAKEOUT

When a 2 l/s ion pump does not reach the desired
base pressure, and there are no leaks, it is
necessary to bake the system. This can be done
by heating the pump and all the components in the
system, and is generally required to achieve less
-8
than 10 mbar base pressures.
•
The pump body can be baked up to 400 °C if
the magnet and the H.V. cable connector
have been removed.
•
If the bakeout is done with magnets and H.V.
cable connected, the maximum allowable
temperature is 150 °C and the pump control
unit can be left on in order to be able to
monitor the pressure variations. During the
bakeout cycle the pressure must not increase
-5
above 5x10
turn the bakeout off and then on again when
low pressure is restored.
•
Bake the 2 l/s pump for 24 hours. Longer
bakeout periods are recommended when the
pump has been used with heavy gas load
applications.
•
Wait until the pump cools down to room
temperature and recovers its initial pressure
before using it in the application.
13
TECHNICAL INFORMATION
WARNING!
mbar, if this value is reached,
87-900-091-01(B)