How to Steam Sterilize the Pleated Filter Element?

When the membrane pleated filter element is used in the production process that requires a sterile environment, the membrane pleated filter element and Stainless Steel Filter Housings are generally disinfected and sterilized with dry saturated steam before use. For example, the disinfection and sterilization process of liquid, gas and air in the food and beverage production process, etc. The commonly used membrane pleated filters include PP Pleated Filters, Nylon Pleated Filters, PES Pleated Filters, Glass Fiber Pleated Filters, PTFE Pleated Filters and PVDF Pleated Filters, etc.

Let's take a look at how to steam sterilize the membrane pleated filter element. The steam sterilization process of the membrane pleated filter element is as following:

● Since we only steam the Membrane Pleated Filters and the filter housing, we must keep the inlet valve and outlet valve closed during the entire steam sterilization operation;

● Make sure that all valves are closed;

● Fully open the steam discharge valve (V2), filter housing discharge valve (V5), filter housing exhaust valve (V6), and then fully open the steam supply valve (V1);

● Allow enough time for all the condensed water to be completely discharged through the steam discharge valve (V2), slowly open the steam inlet valve (V3), and then close the steam discharge valve (V2);

● Allow enough time for all condensate to be completely discharged through the filter housing discharge valve (V5), and then close the filter housing discharge valve (V5);

● When the steam flows out of the filter housing exhaust valve (V6), slowly close the filter housing exhaust valve (V6) to make if half-open;

● Observe the pressure difference between the pressure gauges P1 and P2, when the pressure difference is less than 0.34bar, slowly open the downstream discharge valve (V7). When opening the downstream discharge valve (V7), make sure that the pressure difference does not exceed 0.34bar, otherwise it may cause damage to the membrane pleated filter cartridge;

● Allow enough time for all condensate to be completely discharged through the downstream discharge valve (V7);

● Ensure that the steam passes through the membrane pleated filter cartridges for no less than 30 minutes. Since the pressure of the pressure gauge P1 exceeds 1.38bar, the steam temperature may cause damage to the Membrane Pleated Filter Elements. Therefore, monitor the pressure gauge P1 and ensure that its pressure value is always maintained between 1.03bar and 1.38bar. Moreover, during the entire steam sterilization process, the filter housing exhaust valve (V6) should be adjusted to ensure that the pressure difference between the pressure gauges P1 and P2 does not exceed 0.34bar;

● After the steam has passed through the membrane pleated filter element for more than 30 minutes, close the steam discharge valve (V2), filter housing discharge valve (V5), downstream discharge valve (V7) and filter housing exhaust valve (V6);

● Adjust the supply pressure of compressed air to make it 0.34bar larger than the pressure of the pressure gauge P1;

● Close the steam inlet valve (V3) and steam supply valve (V1), and then immediately open the compressed air supply valve (V4);

● Open the filter housing exhaust valve (V6) slowly and instantaneously to exhaust the steam in the system, and then make sure that the filter housing exhaust valve (V6) is completely closed;

● After the temperature of the system cools to 82 degrees Celsius, close the compressed air supply valve (V4), and instantaneously open the filter housing exhaust valve (V6) to release the pressure in the system, and then ensure that the filter housing exhaust valve (V6) is fully closed.

Precautions for Steam Sterilization of Membrane Pleated Filter Elements

● The filter housing to be steam sterilized must be kept clean and dry, otherwise the contaminants in the filter housing will damage the filter housing under high temperature and high pressure;

● In the steam sterilization process of the membrane pleated filter element, the filter housing discharge valve (V5), the pressure difference between P1 and P2 must be controlled within 0.34bar, otherwise the filter cartridge may be damaged;

● If the membrane pleated filter cartridge has been used in a non-aqueous solvent(such as alcohol), the non-aqueous solvent must be cleaned from the pleated filter cartridge before steam sterilization, otherwise the filter membrane may be damaged during steam sterilization;

● If the pressure difference between the pressure gauges P1 and P2 is less than 0.34bar, and the steam pressure can not support normal operation of the sterilization filtration, the membrane pleated filter cartridge may have been contaminated, and the steam sterilization operation should be repeated at this time;

● The steam and compressed air used in the steam sterilization process of the membrane pleated filter cartridge must be filtered to ensure that the compressed air and steam do not contain particles, bacteria and other pollutants, otherwise the service life of membrane pleated filter cartridge and the filter housing will be shortened.

Steam sterilization is one of the effective and reliable methods for disinfection and sterilization of membrane pleated filter cartridges and filter housings. It has been widely used in the disinfection and sterilization of membrane pleated filtration systems in the food and beverage production process. Although this is an efficient sterilization method, if the operation is not standardized, it is very likely to cause damage to the membrane pleated filter cartridge. Therefore, when steam sterilization of the membrane pleated filtration system is carried out, it must strictly follow the operating specifications.