Definition
A drying sterilization oven is a device that uses dry hot air for sterilization and drying. It denatures microbial proteins through high-temperature heating, achieving sterilization goals. Structurally, it usually includes a heating system, air supply system, and temperature control system. Simply put, this thing is about "baking" and sterilizing items, commonly found in laboratories and food chains.
Principle
The core relies on the convection and radiative conduction of hot air. At high temperatures, proteins coagulate and nucleic acids are destroyed, causing microorganisms to die. Calculation formula (simplified):Q = m · c · ΔT, among themQIt is heat,mIt's the quality of the items,cis the specific heat capacity, ΔTIt is the temperature difference. Actual sterilization depends on the combination of temperature and time, such as maintaining 160°C for 120 minutes or 180°C for 30 minutes. Have you ever seen this formula in high school? However, when applying, attention must be paid to even heat penetration—uneven airflow reduces sterilization effectiveness.
Measurement method
To verify sterilization effectiveness, conventional biological indicators (such as thermophilic lipophilus spores) or chemical indicators are used. For temperature distribution testing, use multi-point thermocouples, with probes placed on the upper, middle, lower, and front and rear inner walls. Referring to the GB/T 30435-2013 standard, both no-load and full load must be tested. Don't rush when measuring temperature—wait until the temperature stabilizes before recording, or else the data will make you feel guilty.
Case study
A certain food laboratory handled glassware by boiling for disinfection, but the bottle walls were always covered with water stains. After switching to a drying sterilization oven, baking at 160°C for 2 hours reduced the total bacterial count from 150 CFU per dish to zero. Another time, a microbiome was baking a petri dish at 180°C, but the wire basket lacked paper, resulting in localized carbonization at the bottom of the dish—caused by a temperature dead angle. The lesson is: don't crowd things together, leave some breathing room.
Application:
Mainly covers several areas: laboratory glassware and metal instruments; Packaging materials and heat-resistant sensors in the food industry; Drying and dehumidifying cosmetics or electronic components. Be careful not to dry combustible solvents or plastics—once, my buddy stuffed a marker in it and almost blew up the oven. In practice, in some cases, it is also used to age materials and simulate high-temperature environments for lifespan testing.
Selection
First, let's look at the temperature control range: generally 50-300°C, which must be sufficient to cover sterilization needs. Volume is selected based on sample size—too much energy consumption to fill the space. Air duct design is crucial; try to choose a top-side supply side return air or horizontal circulation structure. A temperature control accuracy error of ± 1°C is sufficient, but if you conduct precise spore tests, ± 0.5°C is even better. When writing the bidding documents, don't just look at the parameters; ask about wind speed—below 0.5m/s can cause a thermal blind spot. User-friendly features like timed alarms and over-temperature protection are better than nothing.