One of our customers, a manufacturer of food packaging equipment, requires a solution for aseptic packaging. They choose to supply hydrogen peroxide into their aseptic sterilization process for food processing. As a solution, a vapor generating system consisting of liquid flow controllers, gas flow controllers, and a temperature-controlled mixing and evaporation device, from Bronkhorst, can provide the necessary vapor generation and control to ensure food safety.
Food products need sterilization as a final step in the process. In aseptic sterilization, foods require sterilization outside the packaging. Steam sterilization is a common choice for sterilizing foods before packaging. After that, the foods are placed in the aseptic packages that have been sterilized previously in a separate process. Finally, the packages undergo sealing under sterile conditions.
For this application, a compact liquid flow controller controls a low flow of hydrogen peroxide solution (flows of ca. 1 kg/h). It injects the hydrogen peroxide into the packaging, hitting every surface. PET bottles, cartons or pouches, and caps all undergo separate sterilization. After the sterilization step, the remaining hydrogen peroxide can be useful for air drying.
To produce highly accurate and controllable vapor streams, a CEM system or vapor generation system is a great choice. For this application, the vapor generation system, or Controlled Evaporation System, consists of two Bronkhorst Controlled Evaporation Mixers (CEM). One side will sterilize the PET bottles, cartons or pouches, and another side sterilizes the caps.
The hydrogen peroxide (35% H2O2 in water) injects as a vapor for better concentration control. In doing so, the vapor condenses at the inside surfaces of the packaging, and the H2O2 in the liquid phase performs its sterilizing action. Following sterilization, hot air from the gas mass flow controller removes the condensate. Afterwards, the dry and aseptically sterile packaging is ready for filling.
The vapor-generating CEM systems each consist of a liquid mass flow controller (thermal LIQUI-FLOW or Coriolis-based mini CORI-FLOW), an EL-FLOW Select mass flow controller for air as a carrier gas (and for drying afterwards), and a temperature-controlled mixing and evaporation device.
The hydrogen peroxide accurately applies to packaging in the range of 200 (for caps) to 2000 (for cartons and pouches) g/h of H2O2 solution. The flow of drying air is typically around 100 l/min. The liquid, gas, and temperature controllers communicate easily with a PLC for optimum integration in the customer’s systems. Best of all, it’s ethernet enabled which means Modbus or other protocols can provide remote access, control, and data logging.
Due to its robust configuration with direct through-flow measurement, the thermal LIQUI-FLOW requires minor mounting precautions to operate inside the customer’s systems. At this time, more than 100 vapor-generating solutions (CEM) are in use worldwide on aseptic sterilization systems.
As an alternative, use of the mini CORI-FLOW flow controller is an option. The advantage of using a mini CORI-FLOW, in addition to its medium-independent mass flow, is that it allows measurement of the density of the medium. Since hydrogen peroxide will eventually decompose into water and oxygen, the physical properties of the H2O2 solution are not constant over time. Therefore, this device is able to monitor the concentration and, hence, the quality or purity of the hydrogen peroxide.
The hydrogen peroxide injects in a controllable way, so as to not supply too much. As a result, this reduces the costs of this sterilizing agent are reduced. Using this solution, the aseptic sterilization process is well-monitored and traceable, contributing to the extension of the shelf-life of food products.
Copyright 2024 © All Rights Reserved Worldwide
