Autoclave
In
1884 Chamberland developed the autoclave which stimulated the growth of
microbiology. The
autoclave is a steam-pressure sterilizer and a device autoclave
is somewhat like a fancy pressure cooker. The moist heat sterilization must be carried
out at temperatures above 100°C, and this steam produced by the vapor given off by water when it
boils at 100°C. At this point the steam trapped and compressed, its temperature
rises as the pressure on it increases. This steam is dispersed into the jacket and
into the autoclave’s chamber. The steam in the chamber is forced out till the
chamber is filled with saturated steam and the outlets are closed until the
chamber reaches the desired temperature and pressure, usually 121°C and 15
pounds of pressure. This process is maintained for at least 15 minutes to
provide a margin of safety. This duration is based on the size of the container. At this condition,
pressurized steam can able to kills bacterial endospores, vegetative cells, and
other forms of microbes quickly and effectively at temperatures much lower and
less destructive to materials than are required in a dry-heat oven (160 to
170°C). If autoclaving procedure should not carry out properly the processed materials
will not be sterile. Ex. Air not been flushed inside the chamber, desired
temperature (121°C) will not reach. And the chamber should not pack tightly
because steam freely needs to circulate inside the chamber.
There
are different types of autoclave are available based on our requirements viz., Simple autoclave (look like a pressure cooker and not jacketed,
usually used in laboratory), Steam jacked
autoclaves (it got an automatic air and condensate discharge) and High pre-vacuum sterilizer (desired temperature
is 135ºC for only 3 minutes at 30 1b/in2 pressure). Amongst, High pre-vacuum sterilizer has some
advantageous property like, shortened time of operation and reduces the
prolonged exposure of heat sensitive materials. The autoclave has the automatic Processes control, which reduce
the time of a skilled operator and safeguard against errors. The thermometer is
available to avoid errors in timing, the holding period.
0 Comments: