THE PROCESS -
17
Maintenance program
Leak test
Fully automatic process for steam autoclaves
With autoclaves equipped with an analogue pressure transducer the leak
test can easily be automatically performed. The leak test is to be per-
formed with an empty chamber. The chamber additionally has to have
been warm, for example as a result of a heating program having been
run beforehand.
The checking process has its own program button (see program list)
which starts with the vacuum system evacuating the chamber. Depend-
ing on the equipment of the sterilizer, steam may pass through before
the evacuation. The pump in the vacuum system stops when a deep vac-
uum has been created. For a short period of time after this evacuation a
slight rise in the chamber pressure takes place which is not due to leak-
age but results from evaporation of condensate and temperature-volume
changes in the recently rarefied residual steam.
It is therefore not possible to establish that an increase in pressure in the
chamber is caused by leakage until conditions in the chamber have sta-
bilized. It is not until about 10 minutes after the pump has stopped that
the pressure and time start to be measured.
A satisfactory leak test allows for a maximum permissible pressure rise
of 13 mbar / 10 minutes.
With double-ended autoclaves, the loading door opens after a com-
pleted leak test either automatically or manually, depending on how it
has been programmed.
A Normal vacuum 5 min.
B Stabilization of chamber atmosphere 10 min.
C Check time 10 min.
D Pressure stepping max. 13 mbar.
Documentation of the process
A panel printer prints out data logged during the process.
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