GB2050855A - Apparatus for separating curd fines from whey - Google Patents

Abstract

Screening apparatus comprises a closed housing (1) having an inlet (7) to deliver whey that contains a substantial portion or curd fines onto an inclined stationary trough (8) which delivers it onto a stationary separating trough (13) whose floor comprises a screen (20) which is inclined in the opposite direction from the trough (8). In passing from trough (8) to screen (20) the whey passes through a slot which distributes it in a thin layer across the screen. In flowing down the screen most of the whey drains through the screen into bin (27), while the remaining whey and the fines are collected in a separate bin (28) in the form of a slurry. This avoids any unacceptable change in texture and colour of the fines, which can therefore be pumped back to a cheese making vat. Pumps (32, 33) are controlled by level sensor (34). Screen (20) is stretched across the bottom of trough (13) between two rods which engage in brackets on the trough sides (Figure 4 not shown). <IMAGE>

Description

SPECIFICATION Apparatus for separating curd fines from whey In cheese making processes, the whey is drained from the curds but the whey can still contain a substantial portion of curd fines.

As the fines represent a valuable product, various types of separators and screens have been used in the past to separate the fines from the whey, such as disclosed in United States patents 2,942,343 and 3,071,860. In general, vibratory screens and dewatering screens have been used in the past to recover fines and in devices of this type the fines are normally exposed to air and thereby tend to dry and clump together, resulting in a change in texture and colour. Because of this, it is not normally possible to return the fines to the cheese making vat, because they produce an unacceptable change in texture and colour in the cheese, thereby downgrading the cheese. Therefore, curd fines, after separation from the whey, are separately packaged and sold as a non-premium, lower-priced product.

Apparatus in accordance with the present invention, however, for separating curd fines from whey, comprises a housing having an inlet to receive whey containing a quantity of curd fines, an inclined stationary delivery trough to receive whey from the inlet, an inclined stationary separating trough disposed to receive whey from the lower end of the delivery trough, said separating trough being located beneath said delivery trough and being inclined in the opposite direction, a bottom surface of the separating trough having an opening, with a removable flexible screen being disposed across the opening, a first collection vessel being disposed beneath the screen and a second collection vessel being disposed beneath the lower end of the separating trough, whereby whey flows downwardly in the separating trough and a portion of the whey passes through the screen and is collected in said first vessel and the remaining portion of the whey and the fines are collected in said second vessel.

It is an important feature of the present invention that the remaining portion of the whey and the fines, which are collected in the second vessel, are in the form of a slurry so that the fines do not dry out and there is no change in their texture and colour, thereby enabling the fines to be returned to the cheese making vat.

The angle of incline of the separating trough is preferably co-ordinated with the mesh size of the screen so that a major portion of the whey is removed, with the fines and the remaining portion of the whey being discharged in the form of a thick slurry into the second collection vessel.

The present separating trough is a simplified construction over vibratory screens, and other mechanical separating devices, as used in the past, and in particular because there are no moving parts, this not only reduces the initial cost of installation and maintenance, but simplifies the cleaning procedure.

Preferably the housing is a closed housing, and the entire apparatus can be readily cleaned-in-place without the removal of any of the components.

Apparatus according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the apparatus with parts broken away in section; Figure2 is a partial vertical section taken along line 2-2 of Figure 1; Figure 3 is an enlarged view showing the lower end of the delivery trough and the upper end of the separating trough; Figure 4 is a section taken along line 4-4 of Figure 2 and showing the mounting of the screen; and Figure 5 is an enlarged view showing the attachment of the screen to a support rod.

The drawings illustrate an apparatus for separating curd fines from whey which includes a generally rectangular closed housing 1 that is supported on a series of legs 2. The housing includes a pair of side walls 3, a pair of end walls 4, a bottom wall 5, and a top6.

The whey which contains asubstantial portion of curd fines, is introduced into the housing through a curved conduit 7 and is discharged onto an inclined, stationary delivery trough 8 which is mounted in the upper portion of the housing.

As shown in Figure 1 and 2, the trough includes an inclined bottom wall 9, an end wall 10 and a pair of side walls 11. The lower end of the bottom wall 9 is formed with a reverse bend 12, as best shown in Figure 3, which is spaced slightly above bottom wall 14 of an inclined, stationary separating trough 13 to define a slot 15. As shown in Figure 2, the trough 13 is located beneath the delivery trough 8 and is sloped or inclined in the opposite direction. The lower trough 13 is provided with a pair of side walls 16 which extend between the side walls 3 of the housing, and the central portion of the bottom wall 14 is formed with an opening 17.As shown in Figure 3, the upper end of the bottom wall 14 has a downwardly extending flange 18 which is secured to the adjacent sidewall 3, and an upwardly curved baffle 19 is mounted above the flange 18 and is connected between the bottom wall 14 and said adjacent side wall 3 to provide a smoothly curved surface for directing the whey into the slot 15.

Located across the opening 17 in the trough 13 is a porous screen 20, preferably formed of a woven plastics material such as polyester, polypropylene or nylon (RTM). The lower edges of the pair of opposed side walls 16 bordering the opening 17 are curved upwardly, as indicated at 21, and the side portions of the screen 20 are disposed over the curved edges.

Eyes 22 are secured at spaced intervals along the length of each of a pair of opposed side edges of the screen 20, and a respective rod 23 extends within the eyes along each of those side edges. The rods 23 are received within selected ones of a series of notches 24 in the side edges of brackets 25 which are mounted on the side walls 16. By positioning the rods 23 in aligned pairs of the notches 24, the tension on the screen 20 can be varied, and by removal of the rods 23 from the notches 24, the screen can be readily removed for repair or replacement.

The lower edge of the screen 20 terminates short of the lower end of the opening 17 to provide a gap 26. Located beneath the screen 20 is a whey bin 27, while located beneath the gap 26 is a slurry bin 28 which is separated from the whey bin by a divider wall 29. Both the whey bin 27 and the slurry bin 28 are provided with sloping, hopper-type bottoms which drain towards outlet conduits 30 and 31, respectively, which are connected to pumps 32 and 33.

In order to provide the desired separation of whey, and retain a portion of the whey with the fines in the form of a slurry, it is necessary to co-ordinate the inclination of the screen 20 with its mesh size. It has been found that utilizing a mesh size in the range of 80 to 150 mesh, along with an inclination of 30' to 40 with respect to the horizontal, and preferably about 309 will provide the desired manner of separation.

As shown in Figure 2, a liquid level probe 34 may be located within one of the bins 27 and 28 and operates to automatically start operation of both pumps 32 and 33when the liquid level rises to the level of the probe. The probe is connected in an electrical circuit with the pumps and a timer so that the pumps will operate for a given period of time sufficient to substantially drain the whey and the slurry from their respective bins. Each of the pumps may be associated with its own independently operable liquid level sensor.

The housing 1 can be provided with one or more observation hatches 35 or windows.

In operation, the whey containing the curd fines is introduced into the conduit 7 and flows downwardly along the bottom wall 9 to the upper inclined trough 8. The flow of the whey is reversed at the lower end of the trough 8 and the whey then passes through the slot 15 which serves to distribute the whey in a thin stream or layer over the inclined screen 20. As the whey flows downwardly over the screen, a major portion of the whey will pass through the porous screen for collection in the whey bin 27, while the remaining portion of the whey and the fines will be discharged from the lower end of the screen through the gap 26 into the slurry bin. When the liquid level in the whey bin reaches the level of the probe 34, the probe will operate the pumps to remove the whey and the slurry from their respective bins.

As the curd fines are not completely separated from the whey but are in the form of a slurry, there is no tendency for the fines to dry out. Thus, the fines retain their coloursand texture and can be immediately returned through operation of the pump 33 to a cheese making vat for incorporation in the same batch, or a new batch, of cheese.

The apparatus of the present invention is a simplified construction having no moving parts other than the discharge pumps 32 and 33. This not only reduces the cost of the unit, but substantially facilitates the cleaning-in-place of the entire unit.

Claims (9)

1. Apparatus, for separating curd fines from whey, comprising a housing having an inlet to receive whey containing a quantity of curd fines, an inclined stationary delivery trough to receive whey from the inlet, an inclined stationary separating trough disposed to receive whey from the lower end of the delivery trough, said separating trough being located beneath said delivery trough and being inclined in the opposite direction, a bottom surface of the separating trough having an opening, with a removable flexible screen being disposed across the opening, a first collection vessel being disposed beneath the screen and a second collection vessel being disposed beneath the lower end of the separating trough, whereby whey flows downwardly in the separating trough and a portion of the whey passes through the screen and is collected in said firstvessel and the remaining portion of the whey and the fines are collected in said second vessel.

2. Apparatus according to claim 1, in which each vessel is connected to respective pumping means to remove material collected therein.

3. Apparatus according to claim 2, in which liquid level sensing means.is disposed in one of said vessels to sense the level of liquid material collected therein, said sensing means being operably connected to the pumping means associated with that vessel to operate that pumping means and remove liquid material therefrom.

4. Apparatus according to any preceding claim, in which said screen is disposed at an angle of 30 to 40 to the horizontal and has a mesh size of 80 to 150.

5. Apparatus according to any preceding claim, in which a slot is defined between the lower end of the delivery trough and the upper end of the separating trough so that the slot can distribute whey as a layer over the screen.

6. Apparatus according to any preceding claim, in which a pair of opposed side edges of the separating trough bordering the opening are curved and the adjacent side portions of the screen pass over said curved edges.

7. Apparatus according to claim 6, in which each of the side edges of said side portions of the screen is connected to a respective rod, each rod being received in selected ones of a series of notches in brackets disposed along the adjacent side wall of the separating trough, positioning the rods within the respective notches serving to adjust the lateral tension on said screen.

8. Apparatus according to any preceding claim, in which the housing is closed.

9. Apparatus according to claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.