CS215538B1 - Method of preparation of sterile air by filtration - Google Patents

Description

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The glass wool used to filter the fluid has a fiber diameter of 8 to 30 μη. The pressure losses of the glass wool filters are in the range of 0.02 MPa to 0.03 MPa, which negatively influences the supply of the required amount of air to the fermenters. When the glass wool is wetted, the pressure losses increase, the flow channels are formed, the filter efficiency is lost and the fermentation process itself can be degraded. The filter itself must then be sterilized again, or the entire cartridge must be replaced.

Sterilization is carried out with steam. Another disadvantage of these filters is the high demands on the space to be placed in the production object and the difficult handling of the filter element itself, ie glass wool, associated with the debris flowing into the handling space, which considerably impairs work hygiene. Filter life of this type is 1 to 3 months, depending on the length of one production cycle.

More preferred in terms of space requirements is a method of preparing sterile air by plate filter filtration, wherein a fine PVC fiber fabric is used as a functional insert and has a lifetime of about 1 month. Sterilized with formalin vapors. Although the capacity of this filter is approximately 2 times greater than the previous one, the major disadvantage of its functional component is its high inhomogeneity due to its method of manufacture. Filtration efficiency deteriorates with time as the patency of the filter cartridge increases locally as the clearance area decreases.

Similarly, nitrocellulose filtration membranes are applied which have high efficiency but on the other hand they are disadvantageous due to their high flammability, low mechanical strength and the consequent high risk of damage, which can lead to degradation of the entire fermentation process. Teflon membranes are similarly used.

Other methods of preparing sterile air are based on the use of filter inserts, either pressed from glass fibers or microporous ceramic inserts. A common drawback of the latter methods for the preparation of sterile air is the relatively high cost and difficult availability of filter cartridges.

The above-mentioned disadvantages of the prior art are eliminated by the method for the preparation of sterile air by the filtration according to the invention, which consists in passing the non-sterile air through at least one layer of microporous glass fiber microfiber filter mass with a mean diameter of 0.5 to 3.8 μΐη. Microfibers with a mean diameter of less than 1.0 μιη make up 50 to 70% of the filter mass.

Advantageously, said paper-type microporous filter material is provided with symmetrically spaced depressions at a depth of 30 to 120 μηα at a non-sterile air inlet side of 24 to 130 over an area of 1 cm ² .

The glass microfibre paper filter mass is useful for the preparation of sterile air in all types of filter systems described above. This material is homogeneous throughout the area and, thanks to its filtration properties, ensures sufficient air supply to the fermentation process in the required quantity and purity. Good resistance to high temperature steam used to sterilize the filtration system. This insert also achieves a longer system life.

Several possibilities for the preparation of sterile air according to the invention are illustrated in the following examples. Example 1

For the preparation of sterile air in the fermentation production of antibiotics, a plate filter made of a frame is used, in which 2 layers of special microporous filter mass are clamped so that they are simultaneously supported by a perforated mat in the direction of the flowing air. The frame with the filter element is then clamped into the filter body itself, to which air is supplied from above under a pressure of 202 kPa. Sterile air is removed from the bottom of the filter housing. This method of preparing sterile air achieves at least 99.995% efficiency.

Example 2

Sterile injectable air is obtained by means of a candle filter having a microporous filter paper wound on the outside of the candle; the paper is sealed on the ends of the structure and inserted into the candles. The candle is located in the filter housing, which supplies air to be treated under pressure. Sterile air is removed through the center of the filter candle for use.

Claims (2)

SUBJECT 1. A process for the preparation of sterile air by filtration, characterized in that the non-sterile air is passed through at least one layer of microporous filter material of glass microfibre paper type with a mean diameter of 0.5 to 3.8 μΐη, than 1.0 µm. 50 to 70% of the filter mass. 2. Method of claim 1, wherein the microporous filter medium used paper type, provided on the input side of non-sterile air symmetrically distributed depressions with a depth of 30 to 120 μιη in an amount of from 24 to 130 per 1 cm area of ^{the second}