Sterilization filters mainly use micro filter cartridges with a large specific surface area and a filtration accuracy of 0.22 μ m or more. They are mainly used to prevent impurities, harmful bacteria, microorganisms, etc. from entering tanks, production lines, sterile rooms, etc., causing changes in water quality, products, and sterile room environment, meeting the process needs of industries such as food, biochemistry, beverages, beer, medicine, electronics, etc.

The main filtering materials commonly used for filters are roughly as follows:

Sterilization filter mixed with cellulose ester

Commonly used to make circular single plate filter membranes for precision filtration of liquids and gases;

Sterilization filter made of polypropylene (PP)

Made into a foldable structure, commonly used in cylindrical filters, with a larger pore size and hydrophilicity, it belongs to coarse filter materials;

Sterilization filter made of polyvinylidene fluoride (PVDF)

Belonging to precision filtration materials, it is heat-resistant and chemically stable, with good steam sterilization resistance, and can be made into hydrophilic filter membranes. It is widely used in the filtration of sterile formulation water and injection water in the pharmaceutical industry;

Sterilization filter polyether sulfone (PES)

Made into a foldable structure, commonly used in cylindrical filters, with good temperature and hydrolysis resistance, hydrophilic material, used for precision filtration of high-precision solutions;

Sterilization filter nylon

Made into a foldable structure, commonly used for cylindrical filters, hydrophilic materials, commonly used for fine filtration of liquids;

Sterilization filter made of polytetrafluoroethylene (PTFE)

Made into a foldable structure, commonly used in cylindrical filters, hydrophobic materials, it is a widely used material that is heat-resistant, chemically stable, and commonly used for fine filtration of water, inorganic solvents, and air.

In addition, filter materials are divided into two types based on their relationship with water: hydrophilic (water wettable) and hydrophobic (water non wettable). Hydrophilic filter materials are mainly used for filtering and sterilizing water or water/organic solution mixtures; Hydrophobic filter materials are used to intercept or "guide" water into the filter membrane. They are mainly applied in solvent, acid, alkali, and chemical filtration, tank/equipment respirators, process gas, and fermentation inlet/outlet filtration.

Sterilization Filter Characteristics of Sterilization Filter

(1) The sterilization filter generally adopts a cross hanging type, with horizontal entry and exit. Multi core filters can be designed as floor standing.

(2) Some usage scenarios are divided into pre filters and fine filters according to actual needs.

(3) Air flow direction: passes through the filter element from the outside to the inside.

(4) The compressed air entering the sterilization filter must first pass through at least three stages of precision filters and dryers. For oil removal, water removal, and dust removal, the oil mist concentration should be ≤ 0.01PPM, otherwise it will affect the service life of the sterilization filter and fail to achieve the expected sterilization effect.

(5) Regular sterilization, 1-2 times a week or month according to actual usage, for 30 minutes each time, using clean saturated steam with a filtration accuracy of 1 μ for sterilization. Steam temperature<140 ℃, steam pressure<0.3MPa. Slowly open and close the valve.

(6) When used as a respirator for tanks and equipment, its main function is to connect to the atmosphere to prevent negative pressure inside the equipment and isolate pollution sources in the air. Its filtration function is not very important, so there are basically no requirements for filtration.

Integrity testing of sterilization filters

In order to ensure the filtration efficiency of the sterilization filter, it is necessary to conduct integrity testing before and after use to ensure its filtration effectiveness. The main integrity testing methods include forward flow, bubble point, and water intrusion testing. The mainstream testing instruments include Pall's Flowstar and Millipore's Intergridest

With the deepening of the implementation of the 98 version of GMP and the implementation of new drug GMP certification inspection and evaluation standards, the integrity testing of filters has received increasing attention from enterprises and drug regulatory inspection officials, almost every inspection must be checked, especially the integrity testing of filters for key processes and key control steps has become a key focus of various types of inspections.

In the above-mentioned material filters, the integrity of the mixed cellulose ester and polypropylene (PP) is difficult to detect and is generally considered undetectable. Therefore, it cannot become a good terminal sterilization filter, and there is a significant risk of sterile quality.

Conventional technical parameters of sterilization filter

Work pressure: 0.6-0.8MPa

Import temperature: 0-80 ℃; 0-121 ℃ (steam)

Filtering accuracy: above 0.22 μ m, belonging to the category of microfiltration

Applicable medium: Used for gas and liquid filtration

Specifications of sterilization filters produced by a certain manufacturer

Project/Model	FCJ-1	FCJ-3	FCJ-6	FCJ-10	FCJ-15	FCJ-20
Air handling capacity	1	3	6	10	15	20
Number of filter cartridges	1	1	1	1	1	1
Air connection diameter a b	G1/2″	G1″	G11/2″	G2″	G2″	G2″
Dimensions (mm)	H	140	150	190	190	190
A	27	36	41	50	75	90
Weight (kg)	8.7	18.2	32	40	48	62