FI56918C - FOERFARINGSSAETT FOER AVSKILJNING AV SKUMMJOELK FRAON MJOELK ELLER GRAEDDE GENOM FILTRERING - Google Patents

Description

ΓβΙ tm ANNOUNCEMENT r λ λ «ρ JSTa lbj (11) utläggnincsskrift abaiö C (45) Patent myanrv'tty 1Π 05 19C0 1¾¾¾ Patent meddelat VT ^ (51) Kv.lkJ / Int.CI. * A 01 J 11/10 ENGLISH I —Fl N LAND W) Patent application - Patentantttknlng 750239 (22) Application date - Aniöknlngtdig 29-01.75 ^ ^ (23) AI bubbling - Giltlgheudag 29-01-75 (41) Has become public - Blivit offentlig 08.09-75

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'(44) Date of sight and moonlight. - 0

Patent and registration authorities '' Ansökan utlagd och utUkrlften publicerad 31.01.80 (32) (33) (31) Pyydetty etuoikeus —Begird prloritet 07-03-7 ^

Sweden-Sweden (SE) 7 ^ 03019-8 (71) Alfa-Laval Aktiebolag, Postfack, S-1A7 00 Tumba, Sweden-Sweden (SE) (72) Alf Rune Glimenius, Handen, Gustav Thorvald Jansson, Tumba,

Karl William Harald Kemi, Uttran, Robert Maurits Sandblom, Farsta,

Sweden s i-Sver ige (SE) (7M Berggren Oy Ab (5k) A method for separating skimmed milk from milk or cream by filtration - The present invention relates to a method for separating skimmed milk from skimmed milk

For a long time, liquid dairy products have been separated by centrifugation. In this way, cream has been obtained from milk with varying degrees of fat content. By centrifugation, low-fat cream is also concentrated for butter production.

It is an object of the present invention to provide an inexpensive alternative to the separation of milk or cream by centrifugation. In order for the invention to arouse practical interest, it is required that the performance of the filter become satisfactorily high. However, the separation of milk by filtration is now known in Swedish Patent Publication No. 17,335. · However, the performance of the device described in this publication is limited by the ability of the cream to rise upwards by gravity to the cream outlet. This involves the flow of milk on the surface of the filter remaining so slow that the cream clogs the surface of the filter 2 5G918 and the device will soon become unusable. Apparently, this device has also not become practically approved. The object of the present invention has now been to find a separation method based on the filter principle which is practically useful on an industrial scale, and this new method is characterized in that the separation is carried out as a filter with a majority of pore diameters of 0.2-10 μm and milk or cream is made to flow along the surface of the filter at a speed of at least 0.5 m / sec from the inlet to the outlet while the skimmed milk passes through the filter under a pressure of at least 0.2 kp / cm and a large part of the cream-containing product is returned to the filter inlet. Following the above instructions, it turns out that the milk or cream grease balls are partially left in the filter without passing through it, partly by a stream of liquid sweeping past the filter surface at a sufficient speed to pull it off the filter surface so that the filter does not clog and become unusable.

Since the fat droplets and bacteria in the milk are of the same size, this means that the skimmed milk obtained is released from the bacteria, and the more efficiently the smaller the pores of the filter. When the fat droplets are properly filtered, the skimmed milk becomes completely bacteria-free. This in turn means that skimmed milk does not need to be sterilized by heating. This result is valuable because heating skimmed milk damages the protein present in it and results in a deterioration in the taste of skimmed milk. It has also been shown that with the present invention it is possible to separate the fat droplets of a dairy product more completely than by centrifugation. Thus, even lighter skimmed milk can be obtained than before, e.g. with a fat content of less than 0.05%, if the separation is carried out as a filter with a maximum pore diameter of at most 1.0.

The higher the rate at which milk or cream flows past the surface of the filter, the less cream accumulates in it. However, the high flow rate results in a correspondingly low condensation of the cream in the product that has just passed the surface of the filter. In order not to make the return of this product to the inlet of the filter unreasonably large, it has been found that said flow rate should not exceed 20 m / sec.

3,56918

If a high level of separation is desired, the milk product can first be separated as a filter with a maximum pore diameter of at most 10. In this case, a cream is obtained which, due to the large size of its droplets, is suitable for the manufacture of butter. Furthermore, skimmed milk with a relatively high fat content is obtained. This skimmed milk is in turn separated by a smaller-pore filter, so that, in addition to the cream, skimmed milk of the desired low fat content is obtained. Thus, a filter with a minimum pore diameter of 0.2 μm is used for this latter separation.

The cream obtained by separating according to the invention, which has a fat content of e.g. 15%, can be further concentrated by repeated separation according to this method to a fat content of e.g. 50%. The cream thus obtained is suitable for the manufacture of butter.

The invention will be described in more detail below with reference to the accompanying drawing, which shows a basic device for carrying out this method, for example from an embodiment of a selected device. More specifically, Figure 1 shows a vertical section through a filter and Figure 2 a flow chart incorporating the instrument. The corresponding details in both figures have the same reference numerals.

In Fig. 1, 1 and 2 denote two plates concave hollow and connected by a screw connection, which preferably form a rectangular cavity 3. A film 4 acting as a filter is pressed between the plates. the rubber seals 5 and 6 seal the cavity 3 from leaks along the facing sides of the slabs. The filter 4 is supported by the filter pressure plate 7, which is a porous material such as sintered stainless steel. Arrow 8 indicates the inlet of a milk product having a temperature of, for example, 50-55 ° C, to which the milk is fed by means of a pump (not shown) which produces the required filtration pressure. Arrow 9a indicates the outlet of the obtained concentrate and arrow 9b the outflow of skimmed milk as it passes through the membrane 4.

Figure 2 shows a flow chart of a device that allows continuous filtration. The pump 10 feeds the inlet 8 of the device and adjusts the required filtration pressure to remove the seal obtained.

Claims (5)

9. The skimmed milk penetrates through the filter 4 and its support plate 7 and leaves the opening 9b due to the constriction of the outlet 9a and the pressure caused by it on the upper part of the cavity 3. The pressure acting through the filter 4 may increase from 0.2 to 3 kp / cm and. the flow rate on the filter surface is 0.5-20 m / sec. A method for separating skimmed milk from milk or cream by filtration, characterized in that the separation is carried out as a filter with a majority of pore diameters of 0. 2-10 / Um, so that the milk or cream is flowed along the surface of the filter (4) for at least 0.5 m / sec. at a speed from the inlet (8) to the outlet (9a) while the skimmed milk passes through the filter under a pressure of at least 0.2 kp / cm 2 and that a large part of the cream-containing product is returned to the inlet of the filter. Method according to Claim 1, characterized in that, in order to obtain light skimmed milk, the separation is carried out as a filter with a majority of the pores having a diameter of at most 1.0 .mu.m. Method according to Claim 1, characterized in that the milk or cream is made to flow along the surface (4) of the filter at a speed of at most 20 m / sec. 1. A method for filtering the genome of a genomic filtration, including a genomic filter with a filter, for which the game of interest is a filter having a diameter of 0.2 to 10 microns, with a maximum of to the current filter (4) with a maximum distance of 0,5 m / s from the end (8) to the end (9a), with a low pressure filter of less than 0,2 kp / cm ^, och att den pä grädde anrikade produkten account större deIen äterföres