Installation
19
GA 05.139/1.02 - 06/99
2.5 Connecting the backing
pump
A two stage rotary vane pump or dry-compression
backing pump is required to support operation of the
MAG.
We recommend using our DRYVAC or TRIVAC pump for
this purpose.
In case of high gas throughput, it may also be necessary
to use a roots blower to achieve the backing pressure
necessary for operating the MAG. We recommend our
RUVAC blower for this purpose or our DRYVAC 251/501
systems.
Fig. 16 shows schematically the design of a pump
system incorporating a MAG with an additional foreline
valve and an isolation valve between chamber and
MAG.
The foreline isolation valve is recommended to protect
the MAG from shock venting in case of uncontrolled shut
down of the backing pump. This valve must be able to
close fast enough to avoid pressure increase in the
MAG.
In case of an oil-sealed backing pump the foreline isola-
tion valve protects the MAG from backstreaming oil
vapor during standstill.
Connect the forevacuum flange of the MAG to the
backing pump.
The torque on the forevacuum connection flange must
not exceed the values shown in Fig. 17.
Warning
The forevacuum line must be tight. Hazar-
dous gases can escape at leaks or the
gases being pumped can react with the air
or humidity. We recommend a leak check.
M
M
q
M < 150 Nm
M
q
< 150 Nm
Fig. 17 Maximum torques for the forevacuum connection
Summary of Contents for MAG W 2010 CHT
Page 63: ...Notes 63 GA 05 139 1 02 06 99...
