Dry heat sterilization of an object is one of the earliest forms of sterilization practiced. It uses hot air that is either free from water vapor or has very little of it, where this moisture plays a minimal or no role in the process of sterilization.[1][2]
The dry heat sterilization process is accomplished by conduction; that is where heat is absorbed by the exterior surface of an item and then passed inward to the next layer. Eventually, the entire item reaches the proper temperature needed to achieve sterilization. The proper time and temperature for dry heat sterilization is 160 °C (320 °F) for 2 hours or 170 °C (340 °F) for 1 hour, and in the case of High Velocity Hot Air sterilisers, 190°C (375°F) for 6 to 12 minutes.[3]
Items should be dry before sterilization since water will interfere with the process. Dry heat destroys microorganisms by causing denaturation of proteins.
The presence of moisture, such as in steam sterilization, significantly speeds up heat penetration.
There are two types of hot air convection (Convection refers to the circulation of heated air within the chamber of the oven) sterilizers:
Gravity convection
Mechanical convection
Mechanical convection processedit
A mechanical convection oven contains a blower that actively forces heated air throughout all areas of the chamber. The flow created by the blower ensures uniform temperatures and the equal transfer of heat throughout the load. For this reason, the mechanical convection oven is the more efficient of the two processes.
High Velocity Hot Airedit
An even more efficient system than convection uses deturbulized hot air forced through a jet curtain at 3000ft/minute.[4]
Dry heat lyses the proteins in any organism, causes oxidative free radical damage, causes drying of cells, and can even burn them to ashes, as in incineration.
^"HVHA TECH | UK | Metafix High Velocity Hot air Sterilisers".
General Referencesedit
Ninemeier J. Central Service Technical Manual (6th ed.). International Association of Healthcare Central Service Materiel Management. p. 159.[permanent dead link]
April 12, 2024
heat, sterilization, object, earliest, forms, sterilization, practiced, uses, that, either, free, from, water, vapor, very, little, where, this, moisture, plays, minimal, role, process, sterilization, contents, process, mechanical, convection, process, high, v. Dry heat sterilization of an object is one of the earliest forms of sterilization practiced It uses hot air that is either free from water vapor or has very little of it where this moisture plays a minimal or no role in the process of sterilization 1 2 Contents 1 Process 1 1 Mechanical convection process 1 2 High Velocity Hot Air 2 Instruments used for dry heat sterilization 3 Effect on microorganisms 4 See also 5 References 5 1 Notes 5 2 General ReferencesProcess editThe dry heat sterilization process is accomplished by conduction that is where heat is absorbed by the exterior surface of an item and then passed inward to the next layer Eventually the entire item reaches the proper temperature needed to achieve sterilization The proper time and temperature for dry heat sterilization is 160 C 320 F for 2 hours or 170 C 340 F for 1 hour and in the case of High Velocity Hot Air sterilisers 190 C 375 F for 6 to 12 minutes 3 Items should be dry before sterilization since water will interfere with the process Dry heat destroys microorganisms by causing denaturation of proteins Further information Moist heat sterilization The presence of moisture such as in steam sterilization significantly speeds up heat penetration There are two types of hot air convection Convection refers to the circulation of heated air within the chamber of the oven sterilizers Gravity convection Mechanical convectionMechanical convection process edit A mechanical convection oven contains a blower that actively forces heated air throughout all areas of the chamber The flow created by the blower ensures uniform temperatures and the equal transfer of heat throughout the load For this reason the mechanical convection oven is the more efficient of the two processes High Velocity Hot Air edit An even more efficient system than convection uses deturbulized hot air forced through a jet curtain at 3000ft minute 4 Instruments used for dry heat sterilization editInstruments and techniques used for dry heat sterilization include hot air ovens incinerators flaming radiation and glass bead sterilizers Effect on microorganisms editDry heat lyses the proteins in any organism causes oxidative free radical damage causes drying of cells and can even burn them to ashes as in incineration See also editSterility assurance levelReferences editISO 20857 Notes edit Textbook of Microbiology by Prof C P Baveja ISBN 81 7855 266 3 Textbook of Microbiology by Ananthanarayan and Panikar ISBN 81 250 2808 0 029 This page has moved HAI CDC HVHA TECH UK Metafix High Velocity Hot air Sterilisers General References edit Ninemeier J Central Service Technical Manual 6th ed International Association of Healthcare Central Service Materiel Management p 159 permanent dead link Retrieved from https en wikipedia org w index php title Dry heat sterilization amp oldid 1152803722, wikipedia, wiki, book, books, library,
