EP2348821A1

EP2348821A1 - Cheese making apparatus with vertical draining column

Info

Publication number: EP2348821A1
Application number: EP09788351A
Authority: EP
Inventors: Eric Schilstra; Sijmen Sipma
Original assignee: Tetra Laval Holdings and Finance SA
Current assignee: Tetra Laval Holdings and Finance SA
Priority date: 2008-10-01
Filing date: 2009-09-30
Publication date: 2011-08-03
Also published as: DE112009002413B4; NL2002044C; DE112009002413T5; DE202009018401U1; PL395915A1; WO2010039033A1

Abstract

An apparatus for making cheese, comprising at least one vertical tubular draining column (1), for receiving cheese curd, which in operation forms a curd column (W) in the draining column (2), and which draining column has at least one perforated section with a jacket (23) enclosing the respective section for operatively collecting whey egressing from the curd column, wherein each jacket enclosing a perforated section is provided with at least one whey discharge pipe, wherein at least one jacket is.provided with a whey circulation system, which comprises at least one whey circulation supply pipe (24) connected to the jacket, and at least one- whey circulation discharge pipe connected to the jacket, as well as pump means (25) connected with these pipes; and wherein at least opposite the whey circulation supply pipe within the jacket whey guide means (26) are provided, which prevent whey supplied by the pump means via the at least one whey circulation supply pipe to the space between the jacket and the perforated section from striking directly against a perforated wall part of the perforated section and the curd column situated behind it.

Description

Title¹ Cheese making apparatus with vertical draining column

The invention relates to an apparatus for making cheese, comprising at least one vertical tubular draining column for receiving cheese curd, which in operation forms a curd column in the draining column, and which draining column has at least one perforated section, with a jacket enclosing the respective section for operatively collecting whey egressing from the curd column, wherein each jacket enclosing a perforated section is provided with at least one whey discharge pipe, wherein at least one jacket is provided with a whey circulation system, which comprises at least one whey circulation supply pipe connected to the jacket, and at least one whey circulation discharge pipe connected with the jacket, as well as pump means connected with these pipes.

In the cheese production process, in a known manner, curd is prepared from milk in a curd maker. Usually, the curd in the curd maker is stirred and cut and the whey thereby released is partly discharged and for the rest is supplied, together with the curd mass, via a buffer tank to an apparatus for producing blocks of cheese. Although cheese can be prepared from curd in many ways, in large-scale cheese production often use is made of so-called prepressing columns. Such a column can comprise one or more hollow vertical tubes, to which, in operation, a mixture of curd and whey is supplied at the top. In the column, the curd is increasingly compacted from the top down, so that at the bottom of the column curd blocks can be cut off. To this end, at the bottom of the column, a horizontally acting guillotine blade is placed. The guillotine blade closes off the column, but is opened periodically, so that the curd column(s) in the tube (can) move down over a predetermined distance. When thereupon the guillotine blade is brought into the closing position again, at the bottom of each curd column a curd block (or multiple curd blocks) is thereby cut off. Thereupon the thus obtained curd blocks can be processed further. A curd column hence moves stepwise in downward direction through a vertical hollow tube. The curd is thereby compressed under the influence of the column's own weight and through the hydraulic action of the whey stream through the curd bed. This is called draining and compacting, which requires the whey from the curd-whey mixture to be discharged.

To this end, the vertical hollow tube is provided with a number of perforated sections. At those sections, which, if more than one perforated section is present, are mostly, though not necessarily, spaced apart in a vertical sense, the column comprises drainage jackets enclosing the perforated sections. The drainage jackets collect the whey egressmg through the openings of the perforated sections and are each provided with at least one discharge pipe for the discharge of whey.

Such column-shaped curd draining apparatuses ai*e known per se from practice and from the literature. Examples are the various types of curd draining apparatuses which are marketed by applicant under the name of Tetra Tebel Casomatic^® and Tetra Damrow DMS^®.

A problem that occurs in column-shaped curd draining apparatuses of the type having a draining column which includes one or more vertical curd receiving tubes is that small curd particles are carried along with the whey flowing through the openings of the perforated sections. These small curd particles, which may for instance have dimensions of less than 1 mm, are also referred to by the term fines. Such fines may accumulate in a jacket behind the perforations of a perforated part, forming a mass of fines, which may lead to problems, such as blockage, reduced drainage capacity and bacteriological problems.

The problem of accumulation of fines has in practice been limited to an acceptable minimum in machines having a column containing multiple curd receiving tubes with perforated sections (Tetra Tebel Casomatic* MC) through the use of a whey circulation system. Using such a circulation system, buildup of fines can be prevented by pumping round the whey collected in a jacket part. By pumping round the whey, the particles of fines remain in motion and cannot sediment on the bottom, so that they do not accumulate into a mass of fines but are discharged together with the whey. The above-indicated designation MC stands for Multi Column and indicates that the draining column can contain multiple perforated curd receiving tubes next to each other. The curd receiving tubes are then placed in a closed outer jacket, with an interspace present both between the curd receiving tubes mutually and between the curd receiving tubes and the outer jacket. Horizontal partitions extending substantially transversely to the outer jacket divide the interspace into a number of draining sections situated above each other, which are each provided with a whey discharge pipe.

In a configuration of distributed curd receiving tubes, provided with perforated sections, within a closed outer jacket, such as it occurs in a Multi Column machine, a whey circulation system can be readily used because the relatively large free space between the perforated curd receiving tubes provides sufficient opportunity to inject the circulating whey stream into the draining sections without the whey stream damaging or disturbing the structure of the curd in the perforated curd receiving tubes. Damage or disturbance of the curd structure can lead to unacceptable problems in the eventually formed cheeses, such as deviations in structure, taste and consistency, which limit marketing. In draining columns of the Tetra Tebel Casomatic^® SC type, however, this is not possible, because such a draining column comprises a single vertical tube, which has one perforated section, or a number of perforated sections situated above each other, with each perforated section having a concentric jacket which is situated at a relatively small distance in the order of some centimeters around the associated perforated section. It is noted that from British patent specification 1281510 (Fromageries Bel) an apparatus of the above-mentioned kind is known, having a tubular draining column for cheese curd, which column at the lower end has a perforated portion, which is surrounded by a jacket for collecting whey. The jacket is connected with a whey discharge pipe, which is provided with a branched-off recirculation pipe, via which, with the aid of a pump, a part of the whey discharged by the whey discharge pipe is recycled to the jacket. The recycled whey, however, is thereby pumped into the jacket directly opposite the perforations of the column. There are no whey guide means involved which prevent the recycled whey stream from striking directly against a perforated wall part of the perforated section and the curd column situated behind it.

Furthermore, from Dutch patent application 8006898 (Koopmans) a curd draining column is known which is perforated over the entire length thereof and is provided with a jacket over the entire length thereof. The jacket is connected with a whey circulation pipe, via which whey from the bottom of the jacket is recycled to the upper end of the jacket. Nor here are there any whey guide means involved, which prevent the recycled whey from striking directly against a perforated portion of the column and the curd column situated behind it.

The object of the invention is to obviate the problem outlined. To this end, according to the invention, an apparatus of the above-described kind is characterized in that at least opposite the whey circulation supply pipe within the jacket whey guide means are situated which prevent whey supplied by the pump means via the at least one whey circulation supply pipe to the space between the jacket and the perforated sections from striking directly against a perforated wall part of the perforated section and the curd column standing behind it.

In the following, the invention will be further described with reference to the appended drawing. Fig. 1 schematically shows an example of a known draining column for draining curd for making cheese;

Fig. 2 schematically shows a part of a cross section of an exemplary embodiment of a draining column according to the invention: Fig. 3 schematically shows in perspective a part of an example of a draining column according to the invention;

Fig. 4 schematically shows an example of a cross section of a draining column with whey pipes according to the invention;

Fig. 5 schematically illustrates in perspective an example of an alternative exemplary embodiment of the invention; and

Fig. 6 schematically shows a cross section of the embodiment of Fig. 5.

Fig. 1 schematically shows an example of a known traditional curd draining apparatus 1, also called draining column, for short. The apparatus shown is of the type marketed by applicant under the name of Tetra Tebel Casomatic^® SC. This apparatus is configured for, in continuous operation, draining whey from a vertical curd column W and producing curd blocks using a dosing device. Often, a cheese making apparatus comprises multiple draining columns. The curd column W is situated in a draining column 2, which substantially consists of a vertical tube, and which in a known manner is closed off at the lower end with a guillotine blade (not shown), which is part of a dosing device 3. At the top of the draining column, in operation, using curd supply means not shown but schematically indicated with an arrow 4, a mixture of whey and curd is supplied to the upper end, funnel-shaped in this example, of the draining column 2. The whey-curd mixture supplied forms a curd column W in the draining column, which has at least one perforated wall part δ. The curd column contains whey, which can egress through the perforated wall or perforated wall parts δ. The perforated wall parts 5 are each enclosed by a closed outer jacket 6, in each case with an interspace 7 between the perforated wall parts and the outer jackets. The perforated wall parts may be cylindrical tube sections, which are circumferentially provided with perforations. Other cross-sectional shapes, such as for instance rectangular or square shapes, are also possible. These tube sections are also referred to as draining sections. In the example shown, three draining sections a, b, and c are present. Each draining section is provided with a whey discharge pipe 11, 12, and 13, respectively. The whey discharge pipes 11, 12, 13 in this example terminate in a common whey discharge pipe 14, which in turn terminates in a whey collecting tank 15. The dosing section 3 may also be provided with a whey discharge pipe, indicated with 16, which in this example is also connected with the whey collecting tank 15. Further, in the pipes 11, 12, and 13, controllable valves Y are arranged, which, under the control of pressure gauges PT, which measure the hydrostatic pressure in the draining sections a, b, and c, regulate the flow of the whey through the pipes 11, 12, 13. Alternatively, for instance time -controlled open-close valves with a mechanical flow resistance in the discharge pipe or a regulable back pressure regulation behind the discharge valve may be used as flow regulator.

A problem that, may occur in such curd draining apparatuses is that an accumulation of fines may form in the draining sections. Fines consist of small curd particles which are carried along with the whey through the perforations in the draining sections. These small curd particles can accumulate in the draining sections behind the perforations and thus lead to problems such as, for instance, blockage of the perforations, limitation of the drainage capacity in that the perforation is unduly covered, and bacteriological problems. By way of example, accumulations of fines are schematically indicated with reference numeral 17.

Fig. 2 schematically shows a part of a cross section of an example of a first embodiment of a draining column according to the invention. The figure shows a draining section 20 of a draining column 2. The draining section comprises a perforated wall part or perforated section 21. The perforated wall part can be part of the tubular column 2. but may also be a separate insert, which is fixed in the column for instance by welding. From the curd column W, which in operation is situated in the draining column. whey is released which can egress via the openings of the perforated wall part 21, as schematically indicated with arrows 22. The egressing whey is collected in a jacket 23 enclosing the perforated wall part. The draining column can have a circular cross section, but other cross-sectional shapes are also possible, as for instance a rectangular or generally polygonal cross section with or without rounded or beveled corners.

The jacket 23 has a shape adapted to the shape of the draining column, and is provided with one or more whey discharge pipes, not shown in Fig. 2, such as the pipes 11, 12, 13 of Fig. 1. Further, Fig. 2 shows a whey circulation supply pipe 24 of a whey circulation system. The whey supplied, indicated with an arrow P, is pumped through pipes of the whey circulation system with the aid of schematically represented suitable pump means 25. An example of a piping configuration will be described in more detail hereinafter with reference to Figs. 3 and 4.

The whey supply pipe 24 shown in Fig. 2 terminates in the jacket 23 in such a way that the whey flows into the lower part of the jacket around the column. Here, whey guide means are used, which prevent the whey stream supplied by the pump means from striking directly against a perforated wall part and, via the openings of the perforated wall, striking the curd column W itself. Such whey guide means can comprise a blind, that is, unperforated, portion 26 of the perforated wall part opposite the whey supply pipe, or a screening plate 26, which is placed in front of the perforations situated opposite the whey supply pipe. The blind portion or the screening plate has a height h, which is at least as great as the height from the upper side of the whey supply pipe to the bottom 25 of the jacket 23. In the example shown in Fig. 2, h should hence be at least equal to the diameter d of the whey supply pipe, because the bottom side of the whey supply pipe is flush with the bottom 25 of the jacket 23. This is desirable because the whey circulation flow must preferably take place over the bottom of the jacket so as to prevent sedimentation of fines in a space under the circulation flow. In the example shown, the height h of the blind portion or the screening plate is slightly greater than the diameter d of the whey supply pipe.

The length of the screening plate 26 or the blind portion 26 along the circumference of the tubular column 2 should also be at least as great as the diameter d of the whey supply pipe 24, but is preferably greater. The height h of the blind portion or the screening plate may decrease abruptly or gradually in the circumferential direction of the column 2 to zero or a minor value at a distance from the whey supply pipe, but it is also possible that the blind portion or the screening plate extends all around the column 2 with a substantially constant height h. In that case, the lower portion of the jacket 23 together with the screening plate or the blind portion forms, as it were, a circumferential gutter, in which the whey supplied via the pipe 24 and possibly other whey supply pipes can flow around the column. The supplied stream of whey flushes away fines ending up in the lower portion of the jacket and prevents fines from sedimenting from higher levels in the jacket, so that permanent accumulations of fines are prevented.

Figs. 3 and 4 schematically show in perspective and in cross section, respectively, an example of a draining section 30 for a vertical draining column of a cheese making apparatus according to the invention. The draining section 30 has a perforated wall portion 31, which is enclosed by a jacket 32. The perforations themselves are not represented. The draining section is part of a vertical draining column, which in this example has a rectangular cross-sectional shape with rounded angles.

The draining section is provided with a whey circulation system having a circulation supply pipe 34 for whey. The supply pipe 34 links up with two pipes 35, 36, which, at two diagonally opposite angles of the rectangular cross-sectional shape, are connected to inlet openings 37, 38 in the jacket. As described hereinabove with reference to Fig. 2, the inlet openings are situated at the bottom side of the jacket 32, opposite to blind or screened parts of the perforated section 31, so that the supplied whey stream is not aimed directly at the perforations and cannot damage the curd mass present behind the perforations. The supply line 34 is provided with a connecting flange for a pipe connected with pump means. The whey supply is symbolized with arrows 39, 40, 41. The inlet openings 37, 38 in this example are situated in the corner portions of the jacket, and the whey stream operatively supplied via the inlet openings, preferably at right angles to the circumferential line of the perforated section, therefore butts against the blind or screened corner poi'tions of the perforated section. The whey stream thereby divides into two partial streams which flow in the hollow space 33 between the jacket and the perforated wall parts along the two sidewalls of the perforated section that adjoin each corner portion.

At the other corners of the jacket, outlet openings 42, 43, are arranged, to which two discharge pipes 44, 45 are connected. The discharge pipes 44, 45 are connected with two opposite ends of a coupling pipe part 46, in this example designed with an enlarged diameter. The coupling pipe part 46 is provided with a return pipe 47, which in turn is connected with the pump means, as symbolically indicated with an arrow 48. The coupling pipe part is furthermore provided with a connection 49 for a conventional drainage pipe of the type as the whey discharge pipes indicated in Fig. 1 with reference numerals 11, 12, and 13. Via the drainage pipe, whey can flow to a whey collecting tank. This is symbolically indicated in Fig. 3 with an arrow 50.

In the example shown in Fig. 3 and Fig. 4, the corner portions of the perforated section are bent slightly outwards, thereby creating a stronger curvature, which enhances mechanical strength and which further promotes an efficient distribution of the whey stream supplied via the openings 37, 38, and promotes the confluence of the whey to be discharged via the openings 42, 43. Other forms of the corner portions of a square or rectangular column are also possible.

For completeness, Fig. 4 schematically shows pump means δl. The pump means provide for circulation of whey in the lower part of a jacket of a draining section. The whey originates from the whey-curd mixture which is present in the draining column. In operation, the whey flows via the perforations of the perforated section into the hollow space 33 between the jacket 32 and the wall 31 of the perforated section. In operation, the hollow space is wholly filled with whey. The whey flows away via the discharge pipes 44, 45, and 46, and is thereupon partly discharged via the connection 49 and a drainage pipe connected therewith, and partly recirculated with the aid of the pump means 51. The circulating whey stream prevents accumulation of fines in the hollow space 33 and in particular in the lower portion thereof.

It is noted that the whey discharge pipes 44, 45, 46 of the whey circulation system in the example shown are in fact part of the regular drainage pipe system. By connecting the return pipe 47 of the circulation system to a regular whey discharge pipe, a separate connection to the jacket is not needed. Naturally, if desired, such a separate connection may be used.

The pump means may advantageously be configured to provide multiple or all draining sections of a draining column with a circulating whey stream using a single pump. Since it is not necessary to circulate a whey stream uninterruptedly to prevent accumulation of fines, it is possible to have a single pump work in a time sharing system, whereby the pump, through controllable valves, is consecutively cyclically connected with whey circulation pipe systems of different draining sections. Thus, in a draining column of the type shown in Fig. 1 having three draining sections a. b. and c, a pump could be consecutively connected with section a, section b and section c and then with section a again, and so forth. But a constant whey circulation per section with an own pump facility per section is also possible if such is desired, for instance because of a high load of fines or fundamentally hygienic reasons.

The exemplary embodiments described above are suitable in particular to be employed in new apparatuses to be built. Figs. 5 and 6 schematically show in perspective and in section an example of an insert which makes it possible also to provide an existing draining column with a whey circulation system. Figs. 5 and 6 schematically show a jacket 60 which encloses a perforated wall part 67, not shown in Fig. 5, of a draining section of a draining column. Provided in the jacket is an opening 61, circular in this example. In the opening 61 an insert 62 is placed. The insert has a flange 63 closing off the opening. The flange may be welded over the opening or (as in Fig. 6) in the opening, or be fixed to the jacket in a different manner closing off the opening.

The flange is furthermore provided with a bore 64 and a piece of tubing 65 aligning therewith. The piece of tubing serves for the supply of whey and is operatively connected with a whey circulation supply pipe. Situated opposite the piece of tubing 65 and the bore 64 is a screening plate 66, which is situated at a distance from the flange 63 and which screens the perforated wall part 67 of a draining section situated opposite the bore 64 from a whey stream P supplied via the piece of tubing.

The screening plate 66 is attached to the flange through one or more spacers. For that purpose, in the example shown, the screening plate has lower and upper edges 68, 69, which are bent back to the flange 63 and which are attached to the flange, for instance by welding. The dimensions of the opening 61 and the screening plate are such that the screening plate can be inserted into the jacket through the opening. A whey stream P now strikes against the screening plate and is diverted to both sides and then flows along the perforated wall part. Upward and/or downward diversion is impeded by the bent edges 68 and 69. However, the bent edges, or one of the bent edges, may be provided δ with one or more recesses to avoid dead angles where fines could settle. An example of such a recess, which in this example is arranged centrally in the upper and/or lower bent edge, is shown at 70 in Fig. 6.

An insert which can be connected with a whey circulation pipe can be arranged in a similar manner in an existing draining column. Such an0 insert for a recirculation pipe may or may not, as desired, be provided with suitable guide means for the whey stream.

Besides the advantage of preventing precipitation of fines, an important advantage of the use of a whey circulation system according to the invention is avoidance of a liquid stream, via the perforations of the5 perforated section, directly striking the curd in the draining column. This is of importance because such a liquid stream could break the curd column or could damage the curd column, which can lead to an undesired structure, consistency or even taste of the eventually formed cheese.

Furthermore, there is a significantly lower chance of bacteriological0 contamination of whey and cheese during production, since an important source of infection from bacteria nestling and replicating in the deposited mass of fines is obviated.

The time between successive cleaning turns can thus be substantially longer without the bacteriological quality of especially the5 drained whey becoming too poor for normal marketing. Also, the duration of a cleaning turn may be shorter, since no masses of fines need to be removed and the overall bacteriological state of the installation at the start of cleaning is substantially better. In cleaning, furthermore, use can be made of the pump means of the whey circulation system, so that the0 impact of the cleaning process is enhanced. It is noted that after the foregoing, various modifications will readily occur to those skilled in the art. Thus, the whey circulation supply pipe in the examples shown and described is preferably arranged in a corner portion at right angles to the circumferential surface of the perforated sections. The whey stream supplied then butts against a rounded surface and divides into two partial streams, which meet at a corner portion situated diagonally opposite the supply pipe and leave the jacket again. A similar effect may be achieved with a circular column if the whey stream is supplied at right angles to the perforated section. In general, by the use of one or more suitable guide plates, the circulation whey stream can be guided through the jacket in the desired manner, while the circulating whey may or may not, as desired, be divided into partial streams. Thus, it is for instance also possible to allow the circulating whey stream to flow into the jacket tangentially and only upon a complete course around the perforated section to discharge it again, just before the point of supply.

To this end, use could be made of a partition between supply and discharge points. Such modifications are understood to fall within the framework of the invention as defined in the claims.

Claims

1. An apparatus for making cheese, comprising at least one vertical tubular draining column, for receiving cheese curd which in operation forms a curd column in the draining column, and which draining column has at least one perforated section, with a jacket enclosing the respective section

5 for operatively collecting whey egressing from the curd column, wherein each jacket enclosing a perforated section is provided with at least one whey discharge pipe, wherein at least one jacket is provided with a whey circulation system, which comprises at least one whey circulation supply pipe connected to the jacket, and at least one whey circulation discharge

10 pipe connected with the jacket, as well as pump means connected with these pipes; characterized in that at least opposite the whey supply pipe within the jacket whey guide means are situated, which prevent whey supplied by the pump means via the at least one whey circulation supply pipe to the space between the jacket and the perforated section from striking directly lδ against a perforated wall part of the perforated section and the curd column situated behind it.

2. An apparatus according to claim 1, characterized in that the whey guide means comprise an unperforated wall part of the perforated section.

3. An apparatus according to claim 2, characterized in that the

20 unperforated wall part extends from the bottom side of the space between the jacket and the perforated wall part up to at least a height h which is equal to the distance between the top side of the whey supply pipe of the whey circulation system and the bottom side of said space between the jacket and the perforated wall part.

25 4. An apparatus according to claim 2 or 3, characterized in that the unperforated wall part extends in circumferential direction of the perforated lδ

section over a distance which is at least as great as the diameter of the whey supply pipe of the whey circulation system. δ. An apparatus according to claim 4, characterized in that the imperforated wall part gradually decreases in height at a distance from the whey supply pipe.

6. An apparatus according to claim 4, characterized in that the imperforated wall part together with the lower part of the jacket forms a gutter extending substantially all around the perforated section.

7. An apparatus according to claim 1, characterized in that the whey guide means comprise a screening plate placed opposite the whey supply pipe.

8. An apparatus according to claim 7, characterized in that the screening plate is part of an insert, which furthermore comprises a flange and connecting means for a whey supply pipe, which connecting means comprise a throughflow opening provided in the flange opposite the screening plate, wherein the screening plate is attached to the flange through at least one spacer, and wherein the dimensions of the flange and the screening plate are chosen such that the screening plate can be inserted through an opening made in a jacket, after which the opening can be closed off by the flange.

9. An apparatus according to claim 8, characterized in that the screening plate is attached to the flange through at least one bent-back upper and/or lower edge.

10. An apparatus according to claim 9, characterized in that at least one bent-back edge is provided with a central recess which faces the flange.

11. An apparatus according to any one of the preceding claims, characterized in that the whey circulation discharge pipe is connected with the jacket via a regular whey discharge pipe.

12. An apparatus according to any one of the preceding claims, characterized in that the whey guide means are configured to effect a division of the whey stream supplied via the whey circulation supply pipe, through the jacket.

13. An apparatus according to any one of the preceding claims, wherein the draining column at least adjacent a perforated section has a substantially rectangular shape in cross section, characterized in that two diagonally opposite corners of the rectangular shape are each connected with a whey circulation supply pipe and that the two other corners are provided with a whey circulation discharge pipe.

14. An apparatus according to claim 11, characterized in that the perforated section has outwardly -bent round corners. lδ. An apparatus according to claim 11, characterized in that the perforated section has beveled corners.

16. An apparatus according to any one of the preceding claims, characterized in that the pump means comprise a pump element, which via controllable valves can be cyclically connected with the whey circulation systems of at least two perforated sections.