DE2240662A1 - PROCESS AND APPARATUS FOR SEPARATING A MIXTURE OF LIQUIDS AND SOFT, PARTICULATE FOOD MATERIALS, IN PARTICULAR FOR PROCESSING WHITE CHEESE FRACTION - Google Patents

Description

Method and device for separating a mixture of liquids and soft, partially. Foodstuffs in the form of foodstuffs, in particular for processing white cheese curd.

For this application, priority is derived from the corresponding U.S. Registration Ser.No. 173 022 of August 19, 1971 in Availed. .

The invention relates to a method and an apparatus for quickly and efficiently separating a Mixture of liquids and soft, relatively delicate, particulate food substances least influence on the properties of the parts to be separated Components and especially for processing white cheese curd, i.e. for effective separating, draining and washing with the least possible change in the properties of the same or loss of fine particles.

Soft unripened cheeses such as curd cheese or white cheese are made from milk, which is enriched by a natural food acid (such as lactic acid) and a coagulating enzyme (such as rennet) or another special coagulant is made to coagulate. In the In practice, the milk is usually pasteurized first, then a lactic acid culture and a small amount of Lafo-

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ORIGINAL INSPECTED

ferment added and then the milk is allowed to stand for a while (usually about 3 to 16 hours), during which the milk can curdle and the curdled milk, the so-called breakage, can settle. Once the milk is in is curdled in the desired manner and "ripened" to an acceptable level of whey acidity, the curd is blended and boiled, and peeled off the whey. The curd is then washed and part of the remains in it Whey is removed and the temperature is lowered at the same time to improve the texture and shelf life of the Improve breakage before packing and placing on the market. The curd is usually made with cream and salt added, and the product as cream cheese or white cheese in different shapes and with different Designations placed on the market.

The dehydration and / or washing of the soft curd, e.g. for the production of white cheese, is usually done by means of perforated plates or with rotating drums or sieves. When large crowds of proportionately Soft curds such as white cheese curd are processed, causes the removal of water or whey through the Mass a compression or "agglomeration" of the same, as a result of which the separation of the liquids is significantly impeded or even partially made impossible. It can be observed in particular that relatively large Pieces of soft fracture deform, fill up the channels used to draw off the liquid, and all of them

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Fill cavities, creating a relatively solid fracture mass. This process is during manufacture of hard cheese (Cheddar cheese) is intended by deforming the fragments until all cavities are formed have disappeared and a solid fracture mass is obtained. The disappearance of the cavities and 'to withdraw the liquid However, the channels serving in the curd are undesirable in the manufacture of white cheese and therefore cause scratching or the formation of drainage channels in the fracture is required so that the required amount of liquid is drained off within an acceptable period of time can.

The compaction and the resulting loosening or creation of drainage channels in the quarry have the undesirable effect of reducing or changing the particle size and increasing amounts of fine particles attack. The conventionally used washing and dewatering process steps are also unsatisfactory since a large part of the product is in the form of smaller particles or fine particles desirably removed from the crowd and either lost or only through difficult and proportionate costly recovery processes can be recovered. By grinding or creating drainage ditches in the fraction for the purpose of better removal of the liquid, the size of the fraction is also changed, see above that the final product consists of particles of non-uniform size

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exists and has an irregular moisture content. For example, large broken masses have different degrees of porosity, which leads to different degrees of drainage, in that some areas are drained more slowly than other areas, so that uniform properties of the product can only be achieved with difficulty or not at all. In addition, larger parts of the breakage can clog the sieve openings, while the finer particles are discharged through the openings in an undesired manner. The difficulties that arise due to the compression or agglomeration of the curd in the screening device also make it difficult to carry out the subsequent operations in which cream and salt are added to the curd, particularly with a view to achieving uniform properties of the product.

As can be seen from the foregoing, there is therefore a need for a new and improved method and apparatus for separating a mixture of liquids and soft, particulate food materials such as white cheese curd from whey or wash water in order to obtain products of uniform consistency throughout.

It is therefore the object of the invention to provide a method and a device for the rapid and effective separation of a mixture of liquids and soft, particulate foodstuffs with the least possible interference

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the properties of the components to be separated, in particular the solids, and when the maximum content is obtained to create on finely comminuted material particles, by means of which a more effective and faster separation of softer, more sensitive and particulate food substances from liquids than by known methods and with known Devices is possible and in particular the separation of relatively large amounts of soft breakage ' (gelatinous curdled milk), especially white cheese curd, of washing water and / or whey in a much shorter time Allow time and continue to rapidly and efficiently drain and wash white cheese curd for manufacture a high-quality end product with an extremely low free water content that can be processed, packaged and put on the market immediately, allow, as well as easily and at low cost adaptable to existing processing equipment and executable or operated by trained operators be.

The method proposed for this purpose is according to the invention characterized in that a mixture of Liquids and soft, particulate food materials into an inclined separating line from a plurality essentially in one plane in mutual Distances between conveying surfaces> which are each inclined at a flat angle with respect to the conveying direction and to slow down the locomotion of across the surfaces

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Slipping substances are introduced, the soft food particles at a slow rate of Interruptions accompanied cascading port movement be brought down over the conveying surfaces, the separated Liquid is diverted between the conveying surfaces, thereby liquid and soft food particles quickly and practically completely separated from each other and the liquid and the soft food particles after " Separation can be collected independently for the purpose of further processing.

The device proposed for carrying out the method is characterized by a separating screen from tilted rods and inclined sieve holders with a large number on the sieve holders at mutual distances transversely fastened and a substantially flat bar screen forming bars, each with one under a relatively small, flat angle with respect to the screen plane tilted upwards, essentially flat conveying surface, all conveying surfaces are inclined downwards at an angle smaller than the angle of inclination of the sieve, furthermore one arranged at the upper end of the sieve and for charging the sieve with a mixture of liquid and soft, particulate food stuffs feed channel, one located below the screen Collecting device for the liquid separated from the particulate food materials and through one to collect the down along the sieve

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lower sieve end migratory and separated at this released Food particle serving device.

According to the invention, the mixture is liquid and relatively soft, particulate Food substances fed to the inclined separating zone, which consists of a plurality at mutual distances arranged conveying surfaces. These conveyor areas expediently consist of the upwardly facing surfaces of a large number of transversely extending bars of a bar screen. Since the separate conveying surfaces of these rods are tilted towards the loading side, the Solids in slow, cascading motion from one conveying surface to the next and along the conveying surface Sieve are brought down, with only very low frictional and impact forces, through which fine particles and could be lost through the sieve. The slight tilting of the individual conveying surfaces upward causes the particulate solids to be soft or gentle from one conveying surface to the next are passed on, the liquid simultaneously passing through the spaces between the rods and can therefore be quickly separated from the solids.

When processing soft, particulate foods such as quark or white cheese, the tilting rod separating sieve has many advantages: A very fast and almost instantaneous liquid separation with greater uniformity than has been possible since then * ^

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Food or fraction is separated on its own machined or treated, with compaction and the inclusion of water, which make an effortless separation impossible make, be prevented; Fine particles are largely retained in the solids and do not go with the separated liquid lost; the solids are separated from the liquids by means of a highly effective separating movement of the solids via a stationary one Sieve in a relatively simple, but operationally safe operation. Of particular note is that the solid, particulate food materials obtained by this processing are inherent in nature are practically unchanged and are immediately available for subsequent processing. In the manufacture of white cheese, therefore, it is possible to break it into relatively large pieces to very small pieces and fine particles rapidly from whey or from wash water and can be processed immediately without additional work steps, e.g. with cream and / or salt etc. be moved.

The invention is described below with reference to the preferred exemplary embodiments shown in the drawings explained in more detail.

Fig. 1 is a diagrammatic representation of an embodiment of the device according to the invention.

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Pig. Figure 2 is a cross-section, to a larger scale, taken along line 2-2 of Pig. I. Pig. 3 is a cross section taken along line 3-3

of Fig. 2.
Fig. 4 is a plan view on a smaller scale

along the line 4-4 of Fig. 2. Fig. 5 shows a section on a larger scale from Fig. 2, to illustrate the structure of the separating screen. Fig. 6 shows an even more enlarged illustration

cut with the details of the rod segments of the separating screen. Fig. 7 is a side elevation of another

Embodiment of a device according to the invention.

The invention is best understood from a description of the apparatus shown in the drawings to understand. In the embodiment shown in Fig. 1, a trough-shaped container 10 is provided, the Dimensions are chosen according to the desired capacity. When the container 10 is used to process White cheese is intended, it has, for example, an upper opening 12 through which preprocessed substances are introduced will. In addition, a conventional agitator (not shown) can be used for the purpose of mixing the white cheese with cream, salt or other ingredients for processing

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be provided until packaging. For this purpose, a drive 14 for the agitator and a bearing 16 are known per se Way provided.

The separating device according to the invention, denoted by 20, is arranged in a self-supporting manner between a feed source and the container opening 12 and supplies the container with dehydrated and / or washed white cheese curd (cottage cheese curd). As can be seen from Figures 1 to k , the device 20 has a frame or housing with side walls 22 and lower, converging housing bottom walls 24, 26 and 28, which separate a collection device for liquid such as whey, washing water, etc. from the solids to be processed form. Also located on the housing is an inlet section 30 at which the liquid-solid mixture is introduced into the device and fed to the separator screen, shown at 32, along a conveying path generally parallel to the plane of the separator screen. In addition, a curved delivery plate 34, possibly in the form of a flange, can be located on the housing, which diverts the separated white cheese curd or other soft, particulate food substances into the container 10. The separating device 20 is connected to a charging device 31 such as, for example, a channel or a pipeline for the liquid-solid mixture. The trough-shaped lower housing section is connected in a corresponding manner to a discharge device 33 for the separated liquid.

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As best seen in Figures 2 and 3, are connected to the bottom walls of the housing inclined sieve holders 36, which form the working level for the Specify separating sieve 32. The holder 36. Exist for example of metal rods, which by means of machine screws or other fastening means 39 to the housing are attached. Like from Pig. 5, the holders 36 are aligned parallel to one another and are used for receiving a plurality of mutually spaced bars or rods 40 arranged transversely to the holders. How. in the cutout 6, the rods 40 have a generally triangular cross-section with smooth, im substantially planar upper conveyor surfaces 42. In accordance with the invention, the transverse rods 40 are such tilted so that the conveying surfaces 42 enclose a flat angle (denoted by α) with the screen holders 36. The flat conveying surfaces 42 are in particular under a pointed, relatively flat shape with respect to the sieve plane Angle tilted towards the loading end of the screen, the preferably between about 5 ° to 20 ° (and optimally 15 °). This slight tilting against the direction of travel has the purpose of a slight cascade-like movement of the fragments accompanied by interruptions downwards along the sieve with the simultaneous generation of only minimal frictional and impact forces. This type of locomotion results from the

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have a slight upward tilting of the conveying surfaces with a high inclination angle of the sieve plane, which is represented by the angle β (see Fig. 6). The Siebneigungswinkel with respect to the horizontal is preferably between 30 and 50 ° (and optimally about ¹ IO ^0). With an angle of this order of magnitude, a relatively rapid downward movement of the fragments is achieved with simultaneous effective separation of wash water, whey or any other entrained liquid.

The individual transverse rods ¹ can IO to the brackets 36 by resistance welding oer like. Be attached, the rods must be fixed immovably. Since the sieve is used for processing foodstuffs, the entire separating sieve 32 can be provided with a resistant coating such as a surface coating made of thermoplastic resin, for example made of vinyl, polyethylene or a styrene resin (in particular vinyl chloride or vinyl acetate chloride copolymer). These coatings are tough, odorless, tasteless and non-toxic, making them suitable for food processing without impairing the mechanical properties of the tilting rod separating screen.

The application of the device described above is now based on a specific method for Separating a mixture of liquids and soft, particulate food materials. So is used, for example, in the production of white cheese

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The mixture of curd (curdled milk) and whey (or curd and washing water) is fed to the device through the feed pipe 31. The mixture passes through the screen inlet housing 30 and moves down the surface of the screen 32 due to its own weight. When the fragments (designated by the reference numeral 50 in FIG. 5) come into contact with the conveying surfaces 42 of the tilting rod separator screen, they are given a rolling motion so that they cascade down the inclined screen and soften from one Conveying surface 42 to be passed on to the next. For this reason there is practically no tendency for the nature of the fracture to change due to frictional or compression forces. At the same time, most of the entrained liquid quickly passes through the spaces 52 between the rods (see FIGS. 5 and 6), so that effective drainage or liquid separation from the fracture takes place within a very short period of time. While the break moves downwards in a soft cascade-like manner along the inclined separating screen 32, free quantities of liquid remaining on the surface of the break can pass through the spaces 52. and arrive at the liquid outlet 33. The fragments of a lead over striking movement and arrive in this manner for the delivery plate 34 and reach them virtually free of entrained liquid, undamaged and in an ideal condition to _s with cream,

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Salt and / or flavorings can be added and processed further. The speed of movement The solids along the sieve can additionally be lowered by using restraints or flaps are controlled, which are rotatably mounted on a bracket 37 attached to the frame or housing. The flaps 35 can be rigid or flexible and in this case serve to slow down the movement of Solids and liquids by distributing them evenly over the entire width of the sieve 32.

The angle of inclination of the screen 32 chosen for effective dewatering depends to a certain extent on the Size of the processed fraction. If the break consists of relatively small, hard bits, it moves down the sieve faster than larger, soft fragments and can therefore be moved along with the sieve Process at a flat angle of inclination of 30 to 35. Large, soft fragments, on the other hand, do better on sieves with an angle of inclination of the order of magnitude 40 to 50 ° or more processed. Because of practical reasons the screen inclination angle 3 should be large enough, regardless of the size of the fragments, to be desirable to ensure a high flow rate of these substances over the sieve, but on the other hand be shallow enough to to hold back the break on the sieve long enough to allow the desired burning off of liquids and thus the Drainage is achieved. For these reasons, the

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Screen inclination angle in a range from about 30 ° to 50 ° lie in relation to the horizontal.

The tilt angle α of the conveying surfaces 42 must be sufficiently large to cause a certain deflection of smaller fragments and fine particles to the nearest conveying surface 42, so that these substances _{are carried away via the spaces 52 a} through which the liquid is discharged and never lost for further processing walk. In addition, this angle must be large enough to ensure that the larger particles are not subjected to frictional and impact forces on the edges or sides of the connecting rods 40 as they move down the screen. It has been found that the conveying angle, ie the tilting angle α of the bars should be between 5 ° to 20 ° with respect to the plane of the sieve 32 in order to achieve the desired results when processing white cheese and similar soft, sensitive food substances. In practice it has been shown that an angle of approximately 15 ° represents approximately the optimum value for many process applications.

The operation of the device shown in Figures 1 to 6 is as follows. A mixture of _t · liquid and soft, particulate food substances such as whey and white cheese curd is fed to the device through the feed channel 31. The entering substances are through the upper section, ie

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the sieve inlet housing 30 is deflected to the surface of the separating sieve 32. As can be seen in particular from FIG. 5, move the soft fragments due to the slope of the sieve 32 in connection with the low .Terkippung of Conveyor surfaces 42 upwards in a gentle, overlapping, generally cascading mode of locomotion along the sieve 32 downwards. The sieve inclination angle (indicated by the angle 0) ensures that the Move particles quickly downwards over the sieve surface, with the slight tilting (indicated by the angle α) of the rods causes a deflection of the broken particles upwards, so that they over the interstices 52 to the each of the conveying surface 42 located underneath it. By appropriate dimensioning of the angle of inclination and upward tilting angle of the rods in the manner described above is a rapid advancement of the solid particles along the sieve with the slightest loss of solid particles and practically complete separation of Liquids obtained through the spaces 52 therethrough. The fractional particles 50 move in the direction shown in FIG. 5 Carefully in a rolling motion from one conveying surface 42 to the next and in this way along the screen downward. The relatively small fraction particles shown at 51 move in a corresponding manner or "fine particles" from a tilted conveying surface 42 to the next, whereby they are deflected sufficiently far by these conveying surfaces to move the spaces 52 to the next

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to overcome the following conveying surfaces in more or less the same way as the larger fragments. This is ensures that most of the particulate matter is retained in the final product. In contrast-will entrained liquid such as washing water, whey or another process liquid quickly through the gaps 52 in the through the lower housing walls 24, 26 and 28 formed discharge trough discharged. In practice, most of the liquid is separated in the upper part of the sieve, while liquid adhering to the surfaces of the soft fragments collects on the conveying surfaces 42 and is discharged through the spaces 52 in the lower sieve area. Because the fragments are moving uniformly are distributed over the sieve surface, the solids move towards the lower end of the sieve essentially all liquid and entrained. Separated moisture. The soft fragments move It moves forward gently, not being exposed to abrasion or impact forces on sharp edges or surfaces and there is practically no risk of the particles becoming dense, which retain moisture Bunch up or compact masses.

The above description is of the device and the method using a single Tilting rod separating sieve separating device 20, with which the processing container 10 is charged. Included

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it has been shown that a single, small sieve (for example 28 χ 76 cm in size) delivers just as good results as larger perforated sieves, where the food substances be spread in a known manner, loosened and provided with drainage incisions or ditches have to. Compared to the known devices, the processing time is only half to an eighth of the time since then, the product obtained has a much higher uniformity and quality, and it practically no particles are lost. In conventional processing, in which the contained in a container Amount processed in one operation are used to fill the container, drain the container and Removing the break usually takes 1 to 4 hours. According to the invention, the same operations can be carried out using the separating device 20 according to the invention in half an hour or in an even shorter time carry out. Despite this significant reduction in processing time this result can still be improved significantly by having several separating devices for processing can be used.

In Fig. 7 is an embodiment of the device shown in the three separating devices 20 from tilt rod separating sieves be used. This arrangement can be readily applied to a white cheese processing tank meet the embodiment shown here with a large upper opening 12. There is a further change in FIG. 7 from the generally designated with the reference symbol 5 ^

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th inner flues. These exhaust pipes can consist, for example, of perforated, columnar pipes which are used in connection with a washing process on the tilting separating sieve 32 ¹ . After the drained and washed fragments have been introduced into the container 10, the washing liquid can thus be drawn off through the tubes 5 * J in a known manner. On the other hand, it is also possible to fill the container with water (with little drainage taking place through the pipes 5 ^) by feeding scrap and washing water at the same time through the separators 20 in order to carry out very rapid washing and drainage. In this type of processing, after the processing steps have been performed, the curd is withdrawn through the delivery tube shown at 56. The separating devices can also be connected in series in a manner not shown here (instead of parallel to one another as in FIG. 7), washing liquid being introduced at the upper end of each sieve.

A generalized example is used to show how the device shown in FIGS. 1-6 can be designed and operated. For this purpose it is assumed that freshly cut and cooked white cheese curd should be washed in small pieces. A mixture of curd and wash water is fed to the top of the separator 20 and passes through the screen inlet housing 30 onto the separator screen 32. It becomes a single separator screen 28 cm wide and 6 cm long

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used. The distance between the fastening points of the transverse rods 40 in the longitudinal direction of the sieve is now 4.7. The length of the conveying surfaces 42 in the longitudinal direction of the sieve is approximately 3.1 mm, and the space between the bars is approximately 1.6 mm. The sieve inclination angle β is 40, and the tilt angle α of the rods 15 °. The mixture of curd and washing water (the curd being cut into particles about 6.3 mm in size on average) is in an amount between 379 to 473 liters per minute fed. The container 10 has a capacity of 2270 kg (5000 lb) and is filled with about 1590 kg of mass in a period of about 20 minutes mixed together for about 3 to 8 minutes. The product obtained is drawn off at the bottom of the container and packaged in a manner known per se.

The quark or white cheese obtained with the processing described above generally consists of undamaged Use of uniform consistency, the one essential has a higher proportion of retained fine particles than commercially available white cheese. The break moves exceptionally smoothly and without signs of wear to show about dai; Tilt rod separating screen 32 away, with the result that practically none in processing new fine particles are generated. The outflow through the pipe 33 is relatively free of fine particles and can easily be introduced into the sewer

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will. Similar results will be obtained with breakage of a different nature e.g. for the production of cheddar cheese, as well as food materials such as pasta, white beans, Cherries and other fruits achieved, which are washed and drained before packaging in cans and the like have to.

The method described can be modified and adapted to a large extent, and so can the device described offers many possible uses. Thus, in food processing, it is generally desirable to do all of them To carry out procedures in a closed system. For this purpose, the separating device contains 20 normally a protective cover not shown here in the form of a hood which extends over the entire surface of the separating sieve 32. It is also possible the device proposed according to the invention in connection with a washing and cooling device in the further U.S. Patent application Ser.No. 126 O79 of March 19, 1971 of the same Applicant's proposed design to use. The lower end of the tilting rod separator screen can also be used in In contrast to the shape shown here, which generally lies in one plane, it can also be curved or arched in order to initially achieve a rapid To achieve drainage, which is followed by a more extensive drainage in the delivery area. Through this Explanations should only be indicated that the The method and apparatus are readily adapted to certain

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Products or a wide variety of foodstuffs have it adjusted.

- patent claims -

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Claims (1)

Patent claims: ;1. ^ method for rapidly and effectively separating a mixture of liquids and soft, particulate food materials with a minimum of influence on the properties to be separated Be ^- Stand parts, characterized in that a mixture of liquids and soft particulate maintaining means substances in an inclined arranged separation zone from a wide variety in substantially in one plane at mutual spaced conveying surfaces (42), which are each inclined at a flat angle (α) with respect to the conveying direction and to slow down the movement of over the. Substances sliding over surfaces are introduced, the soft food particles (50) are brought down to a slow, cascade-like movement accompanied by interruptions over the conveying surfaces (42), the separated liquid is drained off between the conveying surfaces, liquid and soft food particles being quickly and practically completely separated from one another and the liquid and the soft food particles after separation are collected independently of one another for the purpose of further processing. 2, method according to claim Ί, characterized in that the separation zone consists of a plurality of transversely arranged upper 309809/10 68 surfaces (42) of relatively short length in the conveying direction is trained. 3. The method according to claim 1 or 2, characterized in that the distance between the conveying surfaces (42) in the conveying direction is dimensioned smaller than the relatively short conveying surfaces. 4. The method according to any one of claims 1-3 »characterized in that that the conveyor surfaces (42) at an angle between 5 ° and 20 ° to the conveying direction. 5. The method according to claim 4, characterized in that the conveyor surfaces (42) aligned at an angle of 15 ° will. 6. The method according to any one of claims 1 - 5> characterized in that that the plane of the conveying surfaces (42) lying essentially in one plane at an angle of inclination (B) arranged between 30 to 50 to the horizontal will. 7. The method according to claim 6, characterized in that the plane is arranged at an angle of 40 ° to the horizontal will. 309809/1068 8. The method according to any one of claims 1-7 »characterized in that that as a mixture of liquids and solid, soft food particles, a mixture of white cheese curd and whey is added. 9. The method according to claim 8, characterized in that the mixture is supplied with a large proportion of finely chopped white cheese curds. 10. The method according to any one of claims 1 - 7 »characterized in that that as a mixture of liquids and soft, particulate food substances mixed with washing water and white cheese curd containing fine fragments is fed. 11. The method according to any one of claims 1-10, characterized in that the separated liquid to the washing area is returned and in this still contained, finely comminuted soft food particles are separated. 12. The method according to any one of claims 1-11, characterized in that that the separated, soft food particles are collected as white cheese curd and mixed with washing water and returned to the washing area, followed by separation of the washed white cheese curd from the washing water is carried out « 309809/1068 13 · Device for carrying out the method according to one or more of claims 1-12, characterized by a separating ^{screen (20) made of tilted rods (1} JO) and inclined screen holders (36) with a large number of transversely fastened and spaced apart on the screen holders a substantially flat bar screen forming rods (40) each with a substantially flat conveyor surface (42) tilted upwards at a relatively small, flat angle (α) with respect to the screen plane, all conveyor surfaces at an angle smaller than the angle of inclination (3) of the sieve (32) are inclined downwards, furthermore a loading channel (31) arranged at the upper end of the sieve and used for loading the sieve with a mixture of liquids and soft, particulate food substances, a collecting device (26) arranged below the sieve , 33) for the liquid separated from the food particulate matter and through a device (10) serving to collect the separated food particles (50) migrating down the sieve to the lower end of the sieve and discharged at the latter. 14. The device according to claim 13, characterized in that the inclined sieve holder (36) consists of two in a mutual distance at a large angle of inclination (3) with respect to the horizontal holding rods exist. 309809/1068 15. The device according to claim 14, characterized in that the angle of inclination (fS) of the holding rods is dimensioned so that the separating sieve made of tilted rods encloses an angle between 30 and 50 ° with the horizontal. 16. The apparatus according to claim 13, characterized in that the screen bars (40) "made of solid bars of generally triangular Cross-sectional profile exist. 17. The device according to claim I3, characterized in that that the flat conveying surfaces (42) of the transversely attached screen bars at an angle with respect to the screen plane are inclined upwards between 5 ° and 20 °. 18. Apparatus according to claim 17, characterized in that the upwardly facing tilt angle of the substantially flat conveying surfaces (42) is 15 °. 19. Device according to one of claims 13-18, characterized in that the arranged below the screen Collecting device made of a much stronger than the separating sieve (32) inclined upwards and for rapid removal the liquid from the sieve serving collecting container (22, 26). 20. The device according to claim 13, characterized in that the collecting device for separated food 309809/1068 particles from one for further processing of these substances serving container (10). 309809/1068 Blank page