Autoclave / Autoclaves

Steam generation in Autoclaves explained

Autoclaves sterilise objects or media in their chamber by exposing them to a high temperature, typically 121oC, and steam pressurised to at least 1.1 Bar G. This steam can be generated by a number of options; heaters in chamber, integral steam generator or an external steam generator.

Heaters in Chamber

This is the standard configuration for the circular chambered Astell Autoclaves. Water is poured into the chamber either manually with the ‘Classic’ models or automatically with the ‘Autofill’ models, this water surrounds the heater element(s) sitting in the chamber. As these elements heat the water the chamber boils and produces steam. This is the simplest of the heating elements and therefore makes the actual autoclave less expensive and requires less servicing.


The drawbacks is that this method takes longer to heat up the chamber that steam heated autoclaves and there are longer cooling times as there is a reservoir of hot water in the bottom of the autoclave which must be cooled along with the load. For those that use their autoclaves infrequently it is more energy conscious thus cheaper to operate. To increase the time efficiency auto-drain and auto-fill options should be chosen.

This option is not suitable for sterilisation cycles where drying is required for porous loads/fabrics.

Integral Steam Chamber

The heating elements in the chamber are replaced by a separate integral generator which produces the steam and gives improved control over the steam production. A mains water supply enters a steam generator which is converted to steam which then enters the autoclave chamber when required. This is a more expensive option but has the advantage of speeding up the cycles and producing dryer loads at the end of the cycle. This option is available throughout the range on Astell autoclaves 95 litres and above.


Direct Steam/ External Steam Generator

This options is for sites which already have a steam supply or are needed for large autoclaves that require a powerful stand alone steam generator. The external steam feed enters directly into the Autoclave. This is available of Astell autoclaves from 95L and above.


For more information about choosing which steam generation option is best for a particular application or on autoclaves in general please get in touch with our technical team on 01954233120, email or fill in the below form: