ASP STERRAD 100, Service Manual

Page: 89 / 309

Theory of Operation
The vacuum subsystem is controlled by the pressure transducer on the
process chamber and by signals from the control subsystem. This
subsystem evacuates the process chamber during the vacuum stage of
the cycle and at the end of the diffusion stage; controls the vacuum in
the chamber during the plasma stage, and admits filtered air to the
chamber during the vent stage.
Vacuum Pump
The vacuum pump evacuates the process chamber during the vacuum
stage of the sterilization cycle, and, under direction of the control
subsystem, maintains the required vacuum during the sterilization
cycle.
The vacuum pump is a two stage, rotary vane, with at least a 5.5 liters
per 1 liter/sec (60 Hz) 4.6 liters a 1 liter/sec (50 Hz) pumping speed
which includes an automatic anti-backflow valve so that less than 10-6
mbar times 1 liter/sec of helium leaks into the chamber with the pump
turned off.
4 4
Note: The vacuum system has the capability of evacuating the
empty, dry, STERRAD
®
sterilizer chamber to a pressure
of 300 mTorr within 5 minutes.
Figure 4-1. Vacuum Subsystem
Theory of Operation Vacuum Subsystem
ASP Service Guide rev. D STERRAD® 100 Sterilizer 4-3