One of the main challenges of the new harmonized standard ISO 16890 is the standardization of the discharge process of the filter element. So far the influence of the static charge of the filter elements was tested for F7 – F9 filters through discharging a filter media probe by dipping it into liquid isopropanol. In the future the complete filter has to be discharged by putting it into a cabinet and conditioning it with isopropanol vapor for 24 hours.
For this purpose a discharge cabinet, considering functionality as well as safety aspects, was developed. This paper will describe the functioning of the cabinet and relate it to the specifications according to ISO 16890-4. Generally the test system allows automated and reproducible discharging of complete filter elements with isopropanol vapor, using minimal resources. The use of isopropanol is limited to much less 1 l and its release controllable, as it is evaporated through a packed bed. High requirements in terms of safety and explosion protection are taken into account, by integrating an additional humidification and a purging function. With all the considered safety features, the setup of the test system in a standard room without any additional ventilation system or an extraction hood is possible. With this execution of a cabinet comparable tests and targeted studies of the key parameters as the conditioning time, humidity, filter material and recharging over time are possible.
As the effects of the discharging process are up to the current state still to some extend unknown, several conditioning processes with different filter elements were performed and the efficiency is measured before and after the process to exemplarily evaluate the change in the efficiency. Therewith the fundamental usefulness of the discharge requirement can be shown....
Session: F3 - Filter Media - Quality Control and Pore Size Analysis III
Day: 13 March 2018
Time: 16:45 - 18:00 h