ASP sterrad NX, Руководство по обслуживанию и устранению неисправностей

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Functional Description
3
Temperature
Temperature monitoring and control are involved in two aspects of the
STERRAD NX Process: heating and cooling of the condenser that
condenses hydrogen peroxide during vaporization, and heating the
vaporizer, chamber walls and door. The temperature control loop
consists of heaters and temperature sensors. There are five temperature
sensors in the system. The are located on the vaporizer, condenser, door,
chamber front, and chamber rear.
Pressure
Pressure monitoring and control are performed by a control loop which
includes the vacuum pump, vacuum control valve, vent valve, three
pressure transducers and an atmospheric pressure switch. The control
system interacts with these components during chamber evacuation,
pressure monitoring, and venting to atmosphere. Two chamber pressure
transducers monitor and control the vacuum process; one ranges from 0-
30 torr and the other ranges from 0-200 torr. The pressure transducers are
attached to a port in the top of the chamber. The vaporizer pressure
transducer monitors and controls the vacuum during the vaporization
pumpdown step; its range is from 0-30 torr. The pressure transducer is
attached to a port in the vaporizer/condenser assembly. The atmospheric
pressure switch is a differential pressure sensor. Its function is to signal
the control system that the interior of the chamber is at or very near
atmospheric pressure.
Hydrogen Peroxide Monitor
During the hydrogen peroxide transfer step, hydrogen peroxide
concentration data are collected from the monitor. The ultraviolet lamp
assembly sits at the top front of the chamber and delivers UV light across
the chamber to the detector mounted at the bottom of the chamber.
Hydrogen peroxide vapor absorbs UV light – reducing the intensity of
light reaching the detector by an amount proportional to the amount of
hydrogen peroxide present in the light path. A photodiode detector
measures the amount of light coming from the lamp, before and during
hydrogen peroxide transfer to the chamber, allowing a calculation of the
hydrogen peroxide concentration. The area under the concentration-time
curve and the hydrogen peroxide rate constant are calculated and
compared to specifications, by the controller. If the limits are exceeded,
the cycle is cancelled.
STERRAD
®
NX
™
Service Guide 19