GB1562437A

GB1562437A - Method and machine for treating slurries

Info

Publication number: GB1562437A
Application number: GB4228276A
Authority: GB
Original assignee: BESNARD R
Current assignee: BESNARD R
Priority date: 1975-10-13
Filing date: 1976-10-12
Publication date: 1980-03-12
Also published as: NL182629C; FR2327862B1; BE846633A; DE2644976A1; FR2327862A1; NL7611275A; NL182629B; DE7631186U1; DE2644976C2

Description

(54) METHOD AND MACHINE FOR TREATING SLURRIES (71) I, RENE BESNARD, a French Citizen of 32, rue de Brest, 35500 Vitre, France, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed to be particularly described in and by the following statement: The present invention concerns a method and a machine for squeezing out the liquid contained in slurries or wet materials having the consistency of slurries, such as fruit pulps etc. By slurries will be understood in the following a mixture of liquid and solids the proportions of the mixture being very variable.

A machine of this type has already been described in British Patent No. 1,503,813, in the name of the Applicant. This machine each comprises a lower endless belt and an upper endless belt. Each belt is guided by guide rollers and the two belts have their adjacent reaches pressed against one another by pinching rollers.

In these machines, as in other known machines, it is necessary to provide means whereby large lateral movements of the belts in respect of the rollers are avoided.

Generally, these means comprise feeler which operate electric control means.

These machines are required to operate in very humid atmospheres which are not suitable for electrical means.

Consequently, one object of the invention or at least a preferred embodiment thereof consists in providing non-electrical means capable of limiting the lateral mve- ments of one or both of the belts.

Furthermore, when such known machines are used for pressing fruit pulp slurry it is preferably to submit the slurry to a first gravity filtering, for example on the upper belt before submitting it to a second filtering under pressure between opposed reaches of the two belts. It is to be noted that the first gravity filtering may, at least in a later stage thereof, be improved by means such as rollers pressing the upper reach of the upper belt. Experience has shown that in some gases the concentrated solids residue which results from the first filtering frequently retains a not negligible amount of soluble material which it is de sired to be separated from the residue, and it is important to be able to recover a maximum of such material, such as the sugars when fruit pulps are treated.

Another object of the invention therefore, at least in its preferred form consists in providing a machine which obviates or mitigates this disadvantage.

According to the present invention there is provided a machine for treating a slurry comprising a movable lower endless belt and movable upper endless belt, each belt being guided by guide rollers and the two movable belts having their adjacent parts pressed against one another by pinching rollers, the arrangement being that the slurry can be subjected to a first filtering operation on an upper reach of the upper belt and a second filtering operation between the two belts, with the mixing of residue from the first filtering operation with a solvent between the two filtering operations in a mixing means of the machine, wherein the mixing means includes an enclosure provided under the end of the upper reach of the upper belt to receive the said residue and having an inlet for the solvent, the said enclosure being provided with an agitator for mixing the solvent and the said residue and the said enclosure being adapted so that the mixture can be discharged therefrom onto the lower belt for the second filtering operation.

Preferably, said mixing means comprises an enclosure into which is poured the residue from the first filtering operation and in which the residue is mixed with water, the said enclosure being provided with an agitator for mixing the water and the said residue, said means for leading the mixture from said mixing means comprising a pourer to deposit the mixture tonto the lower belt in order to submit it to the second filtering operation under pressure.

Preferably, the belt has along its longitudinal edges, rows of studs in the form of pyramids or frusta of pyramids projecting from the belt, all rollers with which the belt engages being provided with grooves at least as deep as the said studs and of V-shape so that on the passage of the belt over each roller the rows engage in the said grooves keeping the alignment of the belt According to another feature each of said studs is composed tof two parts, one of which has the pyramid shape or frusta pyramidal shape and the other is a rectangular plate, the parts being disposed on opposite sides of the belt, the two parts of the stud being joined through the belt by means of fixing members such as rivets.

According to another feature each stud is of conical or frusto-conical shape instead of pyramidal or pyramid frusta shape.

According to another feature of the studs are manufactured in an elastic material.

Examples of the above aspects of the invention as well as other features of the present invention will appear more clearly on reading the following description of the machine illustrated in attached drawings, in which: Fig. 1 is a diagrammatic side view of a machine embodying the invention; Fig. 2 is a view in axial section of a guide roller round which a belt of the machine of Fig. 1 passes; Fig. 3 is an enlarged view in vertical section of one of the belt studs illustrated in Fig. 2; Fig. 4 is a view from above of a-part of the belt shown in Fig. 2; Fig. 5 is a view in partial section of a groove of the roller of Fig. 2; and Fig. 6 is a view in axial section of a guide roller for an endless band shown in Fig. 1.

The machine shown in Fig. 1 comprises an upper belt 1 and a lower belt 2, each having upper and lower reaches. The belt 1 which is a filter belt is driven by the guide rollers 3 and 4, whilst the belt 2 which is also a filter belt is driven and guided by the guide rollers 5 and 6. Auxiliary guide rollers 7 and 8 guide the belt 2 through a cleaning vat 9 in which possibly rollers, not shown, the outer a'cues of which are provided with brushes; clean the belt 2. The vat 9 may also contain a cleaning liquid for cleaning the belt. The whole of this part of the machine concerning the cleaning of the belt 2 is conventional.

The roller 3 is placed at a height substantially higher than the roller 4 so that the upper reach 10 of the belt, extending between 3 and 4 rises smoothly from the roller 4 to the roller 3. The directions of rotation of the rollers 3 and 4 as well as the rollers 5 and 6 are indicated by arrows.

Above the top end section of the reach 10, there is mounted an endless band 11 driven and guided by guiding rollers 12 and 13.

The direction of rotation of each roller 12, 13 is likewise indicated by 3rrows.

The band 1,1 is preferably a band of solid but flexible material such as rubber.

The band 11 has the same width as the belt 1 and therefore as the belt 2. The band 11 exerts a light pressure on the slurry squeezed between 11 and 1. The band 11 is driven at a speed slightly greater than that of the belt 1.

In the immediate vicinity of the roller 3 where belt 1 starts to turn down is placed a flat ejector 13 which guides the slurry residue, transported by the belt 1 and passing on the roller 3, towards the inlet of a mixer 14. The mixer 14 is a vat of part cylindrical shape with its axis horizontal; it is open towards the roller 3. The residue directed by 13 enters the mixer at the upper edge 15 of the mixer opening. An inlet water tube 16 is provided for feeding water into the mixer 14; the tube 16 is preferably horizontally the same length as the mixer 14, and both are equal or substantially equal to the width of the belts 1 and 2; the tube 16 is provided with holes opposite holes in the mixer to feed the mixer with water in a uniform manner over its whole length.Inside the mixer 14 there is provided an agitator 17 of the same length which comprises a set of radial blades, and which turns around on a horizontal axle 18; the agitator 17 serves for the effective mixing of the slurry received from 13 with the water supplied through 16. The level of the mixture reaches-the lower edge 19 and the overflow passes over the edge 19 and is guided by an inclined plate 20 towards the upper reach of belt 2 against which is pressed the lower reach of belt 1.

In the zone where -the reaches of belts 1 and 2 are adjacent and opposite they are pressed against one another by pinching rollers 21 judiciously distributed. A liquid recovery vat 22 is provided under the reach 10. Another liquid recovery vat 23 is provided under the rollers 21. A scraper 24 is provided to remove the dry residue of the mixture from belt 2 after passage of the mixture between the belts 1 and 2. Finally, a tank 25 is provided above the roller 4 and is provided with a spout 26 for pouring the slurry to be treated -onto an inclined plate 27 which guides the slurry towards the reach 10 of the belt 1.

The operation of the machine-of Fig. 1 is has follows. The slurry contained in the tank 25 is poured via spout 26 and directed by plate 27 onto the lower section of the reach 10. The liquid contained in the slurry passes by gravity through the belt 1 in the course of its ascending movement and falls into the vat 22. In reaching the upper section, the slurry is already drier but under the pressure of the band 11, which is solid so that the liquid can only pass through the belt 1, a large part of the liquid still contained in the slurry flows into the vat 22.

It would then be possible, as in known machines, to leave the dried residue to fall directly onto the belt 2, to the left of the roller 3, then to submit it to more filtering under pressure between the belts 1 and 2 pressed against one another by the rollers 21. However, as it is desired to recover a greater quantity of soluble bodies or materials still contained in the residue, the invention proposes mixing with a solution before the second treatment.

Thus the dried residue coming from reach 10 is delivered into the mixer 14 by the plate 13, wherein it is mixed with water which dissolves predetermined soluble material which the initial liquid of the slurry could not dissolve because for example of saturation. The mixture flows over edge 19 under the action of agitator 17 and is then subjected to the second filtering treatment, the filtered liquid being collected in the vat 23.

These machines operate in very humid atmospheres and the use of electrical control or driving means therefore is to be avoided. Therefore, in order to guide transversely the belts 1 and 2 as Fig. 2 shows, in vertical and axial section of the roller 6, grooves 28 and 29 are provided at respective ends of the roller 6. Studs 30 circulate in the grooves 28 and 29, which studs are fixed to the belts, here the belt 2, along their edges. The plan view of Fig. 4 shows how the studs 30 are aligned along one of the edges 31 of the belt 2. Each stud 30 comprises a rectangular plate 32 disposed to one side of the belt 2 and a frustopyramidal block 33 at the other side and the narrow end of which is directed away from the belt 2. The plate 32 and the block 33 are connected through the belt by rivets 34 or equivalent fixing members. The belt 2 is preferably a metal belt like the belt 1.As an example each plate 32 may have a width of 1 cm in the direction of advance of the belt and length of 2 cm in the transverse direction, whilst the height of the block 33 may be 1 cm.

The grooves 28 and 29 of the rollers have a V-section of which the depth is a little greater than the height of the block 33. In guiding the studs 30, or rather the line of studs formed near each edge of the belt, the grooves ensure that the belt does not deviate transversely. The reason for the truncated shape of the studs 30 is understood by the examination of Fig. 5 indicating diagrammatically how the studs orientate as the belt wraps round the roller 6, and the studs lie in groove 28 and it will be seen that the studs do not come into contact with one another. Each of belts 1 and 2 is guided in a similar manner and all guide rollers 3, 4, 5, 6, 7 and ,8 have grooves such as grooves 28, 29.

Fig. 6 shows a section of the roller 12 on which is wrapped the band 11. To ensure the same guiding as for the belts 1 and 2, the band 11 is provided with two ribs 35 and 36 of V-section which are guided by grooves 37 and 36 of the roller 12 similar to the grooves 28 and 29 of roller 6 shown in Fig. 2. The band 11 is made of elastic rubber, the ribs 35 and 36 instead of being constituted by aligned spaced studs 30, are in single pieces welded or vulcanized directly to the band 11. It is obvious that the bands 35 and 36 could also be segmented e.g. spaced studs, to facilitate the winding as Fig. 5 indicates.

Preferably, not only the guide rollers but also the pinching rollers 21 have grooves for receiving the studs 30.

WHAT I CLAIM IS:- 1. A machine for treating a slurry comprising a movable lower endless belt and movable upper endless belt, each belt being guided by guide rollers and the two movable belts having their adjacent parts pressed against one another by pinching rollers, the arrangement being that the slurry can be subjected to a first filtering operation on an upper reach of the upper belt and a second filtering operation between the two belts, with the mixing of residue from the first filtering operation with a solvent between the two filtering operations in a mixing means of the machine, wherein the mixing means includes an enclosure provided under the end of the upper reach of the upper belt to receive the said residue and having an inlet for the solvent, the said enclosure being provided with an agitator for mixing the solvent and the said residue and the said enclosure being adapted so that the mixture can be discharged therefrom onto the lower belt for the second filtering operation.

2. A machine according to claim 1, wherein the said enclosure is a vat of partcylindrical shape open at its upper part for receiving the said residue and on one side for discharged the mixture, the axis of the vat being parallel to those of said rollers and its length equal to or substantially equal to the width of the belts and the agitator being constituted by a rotor having radial blades arranged to rotate in the said vat.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. reach 10. The liquid contained in the slurry passes by gravity through the belt 1 in the course of its ascending movement and falls into the vat 22. In reaching the upper section, the slurry is already drier but under the pressure of the band 11, which is solid so that the liquid can only pass through the belt 1, a large part of the liquid still contained in the slurry flows into the vat 22. It would then be possible, as in known machines, to leave the dried residue to fall directly onto the belt 2, to the left of the roller 3, then to submit it to more filtering under pressure between the belts 1 and 2 pressed against one another by the rollers 21. However, as it is desired to recover a greater quantity of soluble bodies or materials still contained in the residue, the invention proposes mixing with a solution before the second treatment. Thus the dried residue coming from reach 10 is delivered into the mixer 14 by the plate 13, wherein it is mixed with water which dissolves predetermined soluble material which the initial liquid of the slurry could not dissolve because for example of saturation. The mixture flows over edge 19 under the action of agitator 17 and is then subjected to the second filtering treatment, the filtered liquid being collected in the vat 23. These machines operate in very humid atmospheres and the use of electrical control or driving means therefore is to be avoided. Therefore, in order to guide transversely the belts 1 and 2 as Fig. 2 shows, in vertical and axial section of the roller 6, grooves 28 and 29 are provided at respective ends of the roller 6. Studs 30 circulate in the grooves 28 and 29, which studs are fixed to the belts, here the belt 2, along their edges. The plan view of Fig. 4 shows how the studs 30 are aligned along one of the edges 31 of the belt 2. Each stud 30 comprises a rectangular plate 32 disposed to one side of the belt 2 and a frustopyramidal block 33 at the other side and the narrow end of which is directed away from the belt 2. The plate 32 and the block 33 are connected through the belt by rivets 34 or equivalent fixing members. The belt 2 is preferably a metal belt like the belt 1.As an example each plate 32 may have a width of 1 cm in the direction of advance of the belt and length of 2 cm in the transverse direction, whilst the height of the block 33 may be 1 cm. The grooves 28 and 29 of the rollers have a V-section of which the depth is a little greater than the height of the block 33. In guiding the studs 30, or rather the line of studs formed near each edge of the belt, the grooves ensure that the belt does not deviate transversely. The reason for the truncated shape of the studs 30 is understood by the examination of Fig. 5 indicating diagrammatically how the studs orientate as the belt wraps round the roller 6, and the studs lie in groove 28 and it will be seen that the studs do not come into contact with one another. Each of belts 1 and 2 is guided in a similar manner and all guide rollers 3, 4, 5, 6, 7 and ,8 have grooves such as grooves 28, 29. Fig. 6 shows a section of the roller 12 on which is wrapped the band 11. To ensure the same guiding as for the belts 1 and 2, the band 11 is provided with two ribs 35 and 36 of V-section which are guided by grooves 37 and 36 of the roller 12 similar to the grooves 28 and 29 of roller 6 shown in Fig. 2. The band 11 is made of elastic rubber, the ribs 35 and 36 instead of being constituted by aligned spaced studs 30, are in single pieces welded or vulcanized directly to the band 11. It is obvious that the bands 35 and 36 could also be segmented e.g. spaced studs, to facilitate the winding as Fig. 5 indicates. Preferably, not only the guide rollers but also the pinching rollers 21 have grooves for receiving the studs 30. WHAT I CLAIM IS:-

1. A machine for treating a slurry comprising a movable lower endless belt and movable upper endless belt, each belt being guided by guide rollers and the two movable belts having their adjacent parts pressed against one another by pinching rollers, the arrangement being that the slurry can be subjected to a first filtering operation on an upper reach of the upper belt and a second filtering operation between the two belts, with the mixing of residue from the first filtering operation with a solvent between the two filtering operations in a mixing means of the machine, wherein the mixing means includes an enclosure provided under the end of the upper reach of the upper belt to receive the said residue and having an inlet for the solvent, the said enclosure being provided with an agitator for mixing the solvent and the said residue and the said enclosure being adapted so that the mixture can be discharged therefrom onto the lower belt for the second filtering operation.

3. A machine according to claim 1 or

2, wherein the belts are provided along their longitudinal edges with rows of studs of pyramid shape or frusto pyramidal shape, the guide and pinching rollers being provided with grooves at least as deep as the said studs and of V-shape so that as the belts pass over the rollers, the rows of studs engage in the said grooves, aligning the belts.

4. A machine according to claim 3, wherein each stud is composed of two parts, one of which is pyramidal or frustopyramidal in shape and the other is a rectangular plate, the parts being disposed on opposite sides uf the corresponding belt, the two parts being joined through the belt by means of fixing members suc has rivets.

5. A machine according to claim 3 or 4, wherein the studs are conical or frustoconical instead of pyramidal shape.

6. A machine according to any one of the claims 3 to 5, wherein the studs are made of elastic or resilient material.

7. A machine according to any one of the preceding claims, wherein there is provided at least at the end part of the upper reach of the upper belt an endless band of elastic material adapted to press the slurry against the upper belt, the said band having its inner face provided with two ribs of V-section adjacent its edges, the said ribs locating in grooves in guide rollers of the said endless band to ensure its transverse guiding.

8. A method of treating slurries substantially as herein before described with reference to the accompanying drawings.

9. A machine for treating slurries substantially as herein before described with reference to the accompanying drawings.