Dry Heat Sterilizers are used to sterilize and dehydrogenate glass and metalware, including ampoules, injection bottles, infusion bottles, and production equipment. This stainless steel dry heat sterilizer uses dry heat. It is better than the steam sterilizers because the process does not corrode the machine. Can also use the pharma equipment to sterilize liquids with low moisture content and even medicate powders. The process destroys all micro-organisms and does not cause any environmental pollution or inconvenience to humans.
Constructed with stainless steel S.S. 316 L quantity, the dry heat sterilizer confirms the GMP standards & temperature uniformity in the entire chamber is guaranteed. The Different cycles of DHS include the Exhaust cycle, pre-sterilization, sterilization, stabilization, cooling cycles. All these cycles are controlled automatically by PLC operated fully automatic control panel. We provide Graph cum printout for temp recording & validation at 8 – 16 points.
The dry heat sterilization (killing or removal of all microorganisms, including bacterial spores) technique requires a longer exposure time (1.5 to 3 hours) and higher temperatures than moist heat sterilization. Various available dry heat sterilization methods are; hot air oven, incineration, flaming (wire loop), etc.
Dry heat ovens are used to sterilize items that might be damaged by moist heat or impenetrable to moist heat (e.g., powders, petroleum products, sharp instruments).
Principle of Dry heat sterilization using HOT AIR OVEN
Sterilizing by dry heat is accomplished by conduction. The outside surface of the item absorbs the heat, then passes towards the center of the item, layer by layer. The entire item will eventually reach the temperature required for sterilization to take place.
Dry heat does most of the damage by oxidizing molecules. The essential cell constituents are destroyed, and the organism dies. The temperature is maintained for almost an hour to kill the most difficult of the resistant spores.
The most common time-temperature relationships for sterilization with hot air sterilizers are
- 170°C (340°F) for 30 minutes,
- 160°C (320°F) for 60 minutes, and
- 150°C (300°F) for 150 minutes or longer, depending on the volume.
There are two types of dry-heat sterilizers:
- the static-air type and
- the forced-air type.
The static-air type is referred to as the oven-type sterilizer as heating coils in the bottom of the unit cause the hot air to rise inside the chamber via gravity convection. This type of dry-heat sterilizer is much slower in heating, requires a longer time to reach sterilizing temperature, and is less uniform in temperature control throughout the chamber than is the forced-air type.
The forced-air or mechanical convection sterilizer is equipped with a motor-driven blower that circulates heated air throughout the chamber at a high velocity, permitting a more rapid transfer of energy from the air to the instruments.
Advantages of dry heat sterilization
- A dry heat cabinet is easy to install and has relatively low operating costs;
- It penetrates materials
- It is non-toxic and does not harm the environment;
- And it is noncorrosive for metal and sharp instruments.
Disadvantages for dry heat sterilization
- Time-consuming method because of the slow rate of heat penetration and microbial killing.
- High temperatures are not suitable for most materials, e.g., plastic and rubber items cannot be dry-heat sterilized because temperatures used (160–170°C) are too high for these materials.
- The time and temperature required will vary for different substances, and overexposure may ruin some substances.