Sterilization Liquid Loads Description Daniel Clifford, Product Manager Life Science Australia and New Zealand 14-07-2016
Impact of location An even temperature distribution in the autoclave chamber is a function of 1. Air removal 2. Steam distribution 3. Steam quality 4. No hot spots If the temperature distribution is even there is no or very little impact from the location of the object to be sterilized Temperature distribution is normally verified during FAT and SAT/OQ
Cycle overview Consists of 4 parts 1. Air Removal 2. Heat Up 3. Sterilizing Plateau 4. Drying/Cooling
All cycles Heat Up Steam finds cold spots After air removal, steam is injected to the chamber and controlled to reach sterilization conditions in the load and chamber. The steam valve is controlled according to chamber temperature (Temp Probe in chamber) Steam condensates on a colder surface The volume of the condensate is about 1/1000 of the steam volume This creates a local underpressure Since the system strives to equalize more steam moves towards the cold spot until it has been eliminated steam condensate
All cycles Sterilizing plateau After heat up, steam is injected to the chamber and controlled to maintain sterilization conditions in the load and chamber. The steam valve is controlled according to chamber temperature (Temp Probe in chamber) Temperature is typically nominally 121 C held for 15 minutes for liquids and in Bio-Pharma applications For hard goods applications, 134 C for 3 minutes is common in healthcare 115 C for 30 minutes is also common (heat labile liquids) Many variations, there is no magic, although there is tradition!
All cycles Sterilizing plateau Throughout the holding time the temperature measured at the reference measurement point of the sterilizer chamber and the temperature measured at the nominal geometric center of the test pack shall: be within the sterilization temperature band not fluctuate by more than ± 1,5 K not differ from one another by more than 2 K The holding time commences when the sensor at the reference measurement point reaches the set sterilization temperature
P3200 Program Combination For liquids in open container Gravity air removal Load sensor Sterilization 121ºC 16 min Natural cooling
P3200 Liquids in open containers Vacuum liquid Compressed air Start FV32 Steam FV7 FV6 Vacuum, liquid FV9 Gravity Air Removal Vacuum limit: liquid saturation pressure or 100 mbar(a) 1 4 Heat Up Sterilization Natural Cooling PE PE3 0 Equalization 6 2 FV13 FV17 FV12 FV108 V8
P3200 Liquids in open containers Gravity air removal Compressed air FV32 Start Steam FV7 FV6 Vacuum, liquid FV9 Gravity Air Removal The steam Pushes the air out. Density of Air is higher than steam, so it displaces 1 Heat Up Sterilization to drain 4 Natural Cooling Condensation of steam on surface dilution of liquid PE PE3 0 6 Equalization 2 FV13 FV17 FV12 FV108 V8
P3200 liquids in open containers L3200 liquid in closed containers Air Removal: Gravity air removal Steam enters the chamber through baffles on the sides of the chamber Baffles promote steam flow around the chamber to scour air The steam Pushes the air out. Density of Air is higher than steam, so it displaces to drain Air and condensate removed by central drainage ports in chamber base. Well established principle that the drain is the coldest point in the chamber
P3200 Liquids in open containers Natural cooling Compressed air FV32 Start Steam FV7 FV6 Vacuum, liquid FV9 Cooling by vacuum (0.845 bar(a) / 95ºC) 1 Gravity Air Removal Heat Up Vacuum pulses 0.945 0.845 bar(a) Sterilization Boiling and evaporation in vacuum Liquid Volume After Before 2 FV13 PE FV17 PE3 0 6 4 Natural Cooling Equalization FV12 FV108 V8
L3200 Program Combination For liquids in open & sealed containers Gravity air removal Load sensor Sterilization 121ºC 16 min Support Pressure Jacket cooling
L3200 Liquids in closed or open containers Jacket cooling Compressed air Start Steam Cooling by jacket water Support pressure Gravity Air Removal Heat Up Sterilization Jacket Cooling PE Equalization Jacket Water
L3200 liquids in closed or open container - Support Pressure Sterilization of liquids in closed containers -> Need for support pressure to protect bottles 20C 1bar(a) 121C 3.34bar(a) In an ideal gas mixture the total pressure equals the sum of the partial pressures. Air + steam pressures (1.34 + 2 = 3.34 bar(a))
L3200 liquids in closed or open container - Support Pressure Sterilization of liquids in closed containers -> Need for support pressure to protect bottles In start of cooling phase the deltap will be 3.34-1=2.24 bar 121C 3.34bar(a) In an ideal gas mixture the total pressure equals the sum of the partial pressures. Air + steam pressures (1.34 + 2 = 3.34 bar(a))
L3200 liquids in closed or open container - Support Pressure When running L3200 cycles, support pressure is not possible during sterile phase because the steam/air mix is not uniform. The bottles needs to be rigid. Support pressure is applied only during cooling phase.
L3300 Liquids in closed containers, fan assisted Jacket cooling Compressed air Start Steam Gravity Air Removal Cooling by jacket water Fan assisted Support pressure PE Heat Up Sterilization Jacket Cooling Equalization Jacket Water
Sterilization. Steam Sterilizer liquids in closed container Support Pressure
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