Page 28 - MNU PM502 Ph. Micreo practical

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

• Make sure that you have selected the correct cycle before starting the autoclave

Operation of Autoclave:

٭ The lid is closed but the discharge tap is kept open, and the water is heated. As the

water starts boiling, the steam drives air out of the discharge tap.

٭ When all the air is displaced and steam starts appearing through the discharge tap,

the tap is closed.

٭ The pressure inside is allowed to rise up to 15 lbs per square inch.

٭ At this pressure the articles are held for 15 minutes, after which the heating is

stopped, and the autoclave is allowed to cool.

Why the removal of excess air is a must??

Water boils at 100ºC but if we applied positive pressure boiling point of water will

increase and the steams take the temperature of the boiling point Inside the

autoclave there may be two types of steam:

- Saturated steam: condense directly on the object and transfer its heat to the object

efficient sterilization.

- Super heated steam: occurs if there’s air inside the autoclave where the air takes

the temperature of the boiling water but doesn’t condense on the object and so

doesn’t transfer its heat to the object inefficient sterilization.

Unloading the Autoclave

٭ After a run is complete, check the pressure gauge to ensure that the pressure in the

chamber is “0.” If pressure is not released, do not open the door. Inform your PI /

supervisor about the malfunction.

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