7.4.8
VRX vent-restrictor
Use a VRX fixed orifice vent-restrictor to restrict the flow of vent gas into the EXT pump. You can
fit a vent-restrictor directly in the vent-port or the purge-port of the pump, or you can fit a
vent-restrictor to the inlet of a TAV vent-valve or PRX purge-restrictor. The EXT250M pump is
supplied with a VRX10 vent-restrictor fitted in the vent port and purge port. Refer to Section 2.3
for information on the seelction of the correct VRX vent-restrictor.
Vent restrictor
Orifice diameter (mm)
Item Number
VRX10
0.1
B580-66-021
VRX20
0.2
B580-66-022
VRX30
0.3
B580-66-023
VRX50
0.5
B580-66-024
VRX70
0.7
B580-66-025
36
EXT250M Turbomolecular Pump
