SOLID-LIQUID SEPARATION DEVICE AND FILTRATION DEVICE

Abstract

A solid-liquid separation device of the present invention is a solid-liquid separation device, in which a filtration belt (1), a seal belt (8), and a squeezing belt (15) are wound around an outer circumference of a separation roll (7) rotated in a circumferential direction and are able to run along a rotational direction of the separation roll (7), an object (P) to be processed supplied between the filtration belt (1) and the seal belt (8) is sandwiched between the filtration belt (1) and the seal belt (8) on the outer circumference of the separation roll (7) and squeezed by the squeezing belt (15), and the object (P) to be processed is dehydrated by being ventilated by ejecting a ventilation gas toward a radially outer side of the separation roll (7) via a ventilation gas chamber (10) formed in an inner circumferential portion of the separation roll (7), in which the seal belt (8) is a woven fabric of multifilament or a woven fabric obtained by combination of multifilament and monofilament and is a thinner than the squeezing belt (15).

Claims

1. A solid-liquid separation device, in which an endless filtration belt is wound around an outer circumference of a separation roll rotated in a circumferential direction, a seal belt is wound around an outer circumference of the filtration belt, and a squeezing belt is further wound around an outer circumference of the seal belt, and the filtration belt, the seal belt, and the squeezing belt are able to run along a rotational direction of the separation roll, and an object to be processed supplied between the filtration belt and the seal belt is sandwiched between the filtration belt and the seal belt on the outer circumference of the separation roll and squeezed by the squeezing belt, and the object to be processed is dehydrated by being ventilated by ejecting a ventilation gas toward a radially outer side of the separation roll via a ventilation gas chamber formed in an inner circumferential portion of the separation roll, wherein the seal belt is a woven fabric of multifilament or a woven fabric obtained by combination of multifilament and monofilament and is a thinner than the squeezing belt.

2. The solid-liquid separation device according to claim 1, wherein a thickness of the seal belt is 3 mm or less.

3. The solid-liquid separation device according to claim 1, wherein an air permeability of the seal belt is higher than an air permeability of the filtration belt and is within a range of 5 cc/cm.sup.2/min to 1000 cc/cm.sup.2/min.

4. The solid-liquid separation device according to claim 1, wherein an air permeability of the squeezing belt is 3000 cc/cm.sup.2/min or more.

5. The solid-liquid separation device according to claim 1, wherein, when a tensile stress is applied, the squeezing belt breaks with the tensile stress of 20 N/mm or more.

6. The solid-liquid separation device according to claim 1, wherein a warp of the squeezing belt is a polyarylate fiber or a polyparaphenylene benzobisoxazole fiber.

7. The solid-liquid separation device according to claim 1, wherein the filtration belt is at least one kind of a woven fabric of multifilament, a woven fabric of monofilament, and a woven fabric of spun table, or a woven fabric obtained by a combination of at least two kinds of the multifilament, the monofilament, and the spun table.

8. A filtration device in which an object to be processed is supplied from a supply unit onto a filtration cloth wound around a plurality of rolls and made to run, and the object to be processed is filtered by a filtration unit provided on a side closer to a running direction of the filtration cloth than the supply unit, wherein the solid-liquid separation device according to claim 1 is provided on the side closer to the running direction than the filtration unit, and a roll located on the side closer to the running direction than the filtration unit among the plurality of rolls serves as the separation roll, and the filtration cloth is the filtration belt.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a side view schematically showing an embodiment of a filtration device of the present invention.

[0018] FIG. 2 is a side view showing an embodiment of a solid-liquid separation device of the present invention used in the filtration device shown in FIG. 1.

[0019] FIG. 3 is a partially cutaway rear view of the solid-liquid separation device shown in FIG. 2, as viewed from a right side of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] FIGS. 1 to 3 show an embodiment of a solid-liquid separation device of the present invention and a filtration device equipped with the solid-liquid separation device. As shown in FIG. 1, the solid-liquid separation device in the present embodiment is equipped with a filtration belt 1, a roll 2, a separation roll 7, a seal belt 8, a ventilation gas chamber 10 and a squeezing belt 15.

[0021] The filtration device according to the present embodiment has a configuration of a horizontal vacuum filtration device. As shown in FIG. 1, an endless filtration belt 1 is wound around a plurality of rolls 2 disposed parallel to each other with a central axis horizontal and is stretched therearound. One of the plurality of rolls 2 serves as a driving roll 2A and is rotationally driven around the central axis. Therefore, a horizontal portion 1A of the filtration belt 1 that is horizontally laid in an upper part of the device can run to move in a running direction indicated by an arrow F. Further, an object P to be processed supplied from the supply unit 3 disposed on a side behind the horizontal portion 1A in the running direction F is filtered by a filtration unit 4 disposed between the object P to be processed and the driving roll 2A immediately on the running direction F side via the filtration belt 1.

[0022] Here, the driving roll 2A is located at an end portion of the horizontal portion 1A on the running direction F side, and is rotated by a driving unit 5 such as a motor via a variable speed reducer 6 as shown in FIG. 2, thereby causing the filtration belt 1 to run continuously or intermittently at a predetermined pitch. Further, in the filtration unit 4, liquid content of the object P to be processed is suctioned and filtered via the filtration belt 1 by a vacuum tray (not shown) which supports the filtration belt 1 in the horizontal portion 1A. Further, a solid-liquid separation device according to an embodiment of the present invention is disposed on the side closer to the running direction F than the filtration unit 4 as shown by a broken line in FIG. 1.

[0023] In the solid-liquid separation device of this embodiment, as shown in FIGS. 2 and 3, the endless filtration belt 1 and the seal belt 8 are able to run along a rotational direction T around an outer circumference of the separation roll 7 that is rotated in a circumferential direction in the rotational direction T, while being superimposed and wound to sandwich the object P to be processed filtered by the filtration unit 4 therebetween. Here, in the present embodiment, the driving roll 2A of the rolls 2 in the filtration device serves as the separation roll 7, and as for the filtration belt 1, the filtration belt 1 of the filtration device is wound around the separation roll 7 as it is.

[0024] The separation roll 7 (the driving roll 2A) has a substantially hollow cylindrical shape, and a plurality of penetration holes 9 open on its cylindrical surface portion and on a side inward from a range of a width of the filtration belt 1 in a central axis direction of the separation roll 7 as shown in FIG. 3 and along the entire circumference of the separation roll 7 in the circumferential direction. On the other hand, a plurality of ventilation gas chambers 10 communicating with each of the penetration holes 9 are provided on an inner circumferential portion of the separation roll 7 to be isolated from each other, within a range substantially the same as a range in which the penetration holes 9 are formed in the central axis direction, and to divide the inner circumferential portion of the separation roll 7 into arc shapes at substantially equal intervals over the entire circumference of the separation roll 7 in the circumferential direction.

[0025] Further, the same number of ventilation pipes 11 as the ventilation gas chambers 10 is inserted through the further inner circumferential portion of the separation roll 7 from one end side (a right side in FIG. 3) in the central axis direction, and are connected to the respective ventilation gas chambers 10. The ventilation gas A such as air (compressed air) or steam supplied to the ventilation pipe 11 is ejected and ventilated from the penetration hole 9 to the outer circumference of the separation roll 7 via the ventilation gas chamber 10. Further, the ventilation gas A is supplied from a supply source (not shown) to a ventilation pipe 11 fixed to the rotating separation roll 7 via a rotary joint (or a multi-stage rotary joint) 12.

[0026] Further, an automatic valve 13 is provided for each ventilation pipe 11 between a ventilation gas branch chamber 12A on the separation roll 7 side connected to the rotary joint 12 and each ventilation pipe 11. Here, an opening and closing operation of the automatic valve 13 is controlled, when the ventilation gas A from the ventilation gas branch chamber 12A is in the state of being supplied or not supplied to the automatic valve 13 as a signal gas via a supply pipe 13B, by a limit switch 13A which is attached to the separation roll 7 and operates in accordance with the rotational positions of each ventilation gas chamber 10.

[0027] Further, the present embodiment is configured so that the ventilation gas A is continuously supplied only to the ventilation gas chamber 10 located at a predetermined rotational position, among the ventilation gas chambers 10 within a range in which the filtration belt 1 and the seal belt 8 are wound in the circumferential direction around the separation roll 7 by the automatic valve 13 controlled in this way, while being sequentially switched with the rotation of the separation roll 7. That is, when the ventilation gas chamber 10 is at the predetermined rotational position, the automatic valve 13 is opened and the ventilation gas is always supplied to the ventilation gas chamber 10 and is ejected from the penetration hole 9. On the other hand, at positions other than the predetermined rotational position, the control is performed so that the automatic valve 13 is closed and ventilation is not performed.

[0028] On the other hand, the seal belt 8 has substantially the same width as that of the filtration belt 1, is wound around the outside of the filtration belt 1 on the outer circumference of the separation roll 7, and is able to run in the same running direction G as the running direction F integrally with the filtration belt 1 in the rotational direction T of the separation roll 7 (the driving roll 2A). Further, the roll 2B around which the seal belt 8 is wound next to the separation roll 7 in the running direction G is the same as the roll 2 around which the filtration belt 1 is wound as shown in FIG. 2, the seal belt 8 being pulled downward to the side opposite to the filtration belt 1 and separated from the roll 2B, wound around a plurality of rolls 14 and wound in an endless shape to reach the outer circumference of the separation roll 7 again.

[0029] Further, the squeezing belt 15 is further wound around the outer circumference of the seal belt 8 on the outer circumference of the separation roll 7 around which the filtration belt 1 and the seal belt 8 are superimposed and wound in this way. The squeezing belt 15 is also able to run in the same running direction H as the running directions F and G along the rotational direction T on the outer circumference of the separation roll 7 together with the filtration belt 1 and the seal belt 8.

[0030] Further, in this embodiment, the squeezing belt 15 has a width wider than those of the filtration belt 1 and the seal belt 8, and both ends in the width direction are wound around the separation roll 7 to cover the filtration belt 1 and the seal belt 8 beyond each of both ends in the width direction of the filtration belt 1 and the seal belt 8 as shown in FIG. 3. However, if a horizontal width of the squeezing belt 15 is wider than a cake width of the object P to be processed that is sandwiched and squeezed between the filtration belt 1 and the seal belt 8, the horizontal width of the squeezing belt 15 is not necessarily wider than the filtration belt 1 and the seal belt 8, and may be substantially equal to or may be narrower than the widths of the filtration belt 1 and the seal belt 8.

[0031] Furthermore, in the running direction H, the squeezing belt 15 is wound around the common roll 2B around which the filtration belt 1 and the seal belt 8 are wound next to the separation roll 7, and then is sequentially wound around a plurality of rolls 16 disposed between the separation roll 7 and the seal belt 8 wound around the rolls 14, as shown in FIG. 2. Thereafter, the squeezing belt 15 and the seal belt 8 are wound around the roll 14A around which the seal belt 8 is wound just before reaching the separation roll 7 and are wound in an endless shape to reach the outer circumference of the separation roll 7 again.

[0032] The rolls 2B, 14A and 16 around which the squeezing belt 15 is wound have a diameter larger than that of the roll 2 around which only the filtration belt 1 is wound and the roll 14 around which only the seal belt 8 is wound and have a diameter smaller than that of the separation roll 7. Furthermore, one of the plurality of rolls 16 is attached to an arm 17C of a squeezing belt tensioning device 17 that is able to be rotated about a support shaft 17A by a cylinder device 17B and rotates the arm 17C and positions it at a predetermined position, thereby imparting a predetermined tension to the squeezing belt 15.

[0033] Furthermore, the other one of the plurality of rolls 16 has at least one end attached to a bracket 18B of a squeezing belt meandering correcting device 18 which also is made to advance and retract in the running direction H of the squeezing belt 15 by the cylinder device 18A. In this way, by moving the bracket 18B back and forth in the running direction H to finely adjust an inclination of the roll 16 with respect to the running direction H, when meandering occurs in the running of the squeezing belt 15, the meandering is corrected. However, in the filtration device and the solid-liquid separation device of the present embodiment, including these rolls 16, all of the rolls 2, 14, and 16 other than the driving roll 2A (the separation roll 7) is a driven roll that is not connected to the driving unit.

[0034] Furthermore, a squeezing belt cleaning device 19 is provided on a running path of the squeezing belt 15, a separation filtration cloth cleaning device 20 is provided on a running path of the seal belt 8, and a cleaning device (not shown) is also provided on a running path of the filtration belt 1. Further, a receiving tray 21 is provided at a bottom of the solid-liquid separation device. Further, a discharge port 22 which discharges a cake of the object P to be processed subjected to the solid-liquid separation by the solid-liquid separation device is provided below the roll 2B.

[0035] Furthermore, a scraper 23, a wire and the like are provided on the filtration belt 1 and the seal belt 8 which are separated from the roll 2B toward each of the running directions F and G in opposite directions from each other so as to be in contact with the surface being in contact with the object P to be processed. Further, a recovery plate 24 having an arc-shaped cross section is disposed at an interval from the squeezing belt 15 on the outer circumference of a portion on which the filtration belt 1, the seal belt 8, and the squeezing belt 15 are wound around the separation roll 7, recovers the liquid content separated by the ventilation and guides it to the receiving tray 21.

[0036] Further, in the solid-liquid separation device and the filtration device having such a configuration, the seal belt 8 is a woven fabric of multifilament or a woven fabric obtained by combination of multifilament and monofilament and is thinner than the squeezing belt 15. It is desirable that the thickness of this seal belt be 3 mm or less. Further, it is desirable that air permeability of the seal belt 8 be higher than air permeability of the filtration belt 1 and be in the range of 5 cc/cm.sup.2/min to 1000 cc/cm.sup.2/min.

[0037] On the other hand, it is desirable that the air permeability of the squeezing belt 15 be 3000 cc/cm.sup.2/min or more. In addition, it is desirable that the squeezing belt 15 have a strength such that is broken by a tensile stress of 20 N/mm or more when the tensile stress is applied. Further, it is desirable that a warp of the squeezing belt 15 be a polyarylate fiber or a polyparaphenylene benzobisoxazole fiber. It is desirable that filtration belt 1 be at least one kind of a woven fabric of multifilament, a woven fabric of monofilament or a woven fabric of spun table, or a woven fabric obtained by a combination of at least two kind of the multifilament, the monofilament, and the spun table.

[0038] In an embodiment of such a solid-liquid separation device and a filtration device, the object P to be processed filtered by the filtration unit 4 of the filtration device is sandwiched between the filtration belt 1 and the seal belt 8 on the outer circumference of the separation roll 7 of the solid-liquid separation device, and the squeezing belt 15 is further wound around the outer circumference of the separation roll 7 with a high tension. Thus, the object P to be processed is squeezed under a pressing force on the radially inner circumferential side of the separation roll 7 and is dehydrated. Therefore, it is possible to more efficiently reduce the liquid content of the object P to be processed by the dehydration action of the ventilation gas A ejected from the penetration hole 9 formed in the separation roll 7 and the dehydration action of the squeezing provided by the squeezing belt 15. Thus, even if there is a drying process after the solid-liquid separation process of the object P by the solid-liquid separation device, the load in the drying process can be reduced.

[0039] In addition, in the filtration belt 1, the seal belt 8, and the squeezing belt 15 wound around the separation roll 7 with the object P to be processed interposed between them, distances from the central axis of the separation roll 7 are different according to the thickness of the object P to be processed, and the filtration belt 1 is caused to run by being directly wound around the separation roll 7 (the driving roll 2A). The seal belt 8 and the squeezing belt 15 are caused to run via the filtration belt 1 and the object P to be processed. For this reason, a circumferential speed difference occurs between the filtration belt 1 and the seal belt 8 on the outer circumference of the separation roll 7, and a shearing force trying to shear in the circumferential direction acts on the object P to be processed due to the circumferential speed difference. The object P to be processed is efficiently squeezed and dehydrated by the shearing force and the pressing force.

[0040] Further, in the solid-liquid separation device and the filtration device having the aforementioned configuration, the seal belt 8 of the solid-liquid separation device is thinner than the squeezing belt 15 and is a woven fabric of multifilament or a woven fabric obtained by combination of the multifilament and monofilament. Accordingly, when the object P to be processed is squeezed by the squeezing belt 15 via the seal belt 8, the object P to be processed has excellent compatibility with the squeezing belt 15 and has a high follow-up property. For this reason, even if a circumferential speed difference occurs between the filtration belt 1 and the seal belt 8 as described above, or a step is formed at both end portions of the filtration belt 1 and the seal belt 8 in the width direction (the central axis direction of the separation roll 7) due to the thickness of the object P to be processed, it is possible to suppress an occurrence of wrinkles in the seal belt 8.

[0041] For this reason, according to such a solid-liquid separation device and a filtration device, it is possible to prevent an occurrence of a situation in which such a wrinkled portion is bent by being pressed by the squeezing belt 15, and is broken early when performing a long-time solid-liquid separation. Therefore, according to the solid-liquid separation device and the filtration device having the aforementioned configuration, a stable solid-liquid separation can be performed over a long period of time, which is efficient and economical.

[0042] Further, in order to reliably prevent the seal belt 8 from being wrinkled and broken early, the thickness of the seal belt 8 is desirably 3 mm or less as described above. If the thickness of the seal belt 8 is thicker than 3 mm, wrinkles occur and it is difficult to return to the original state when a fold is formed, and breakage is likely to occur from the folded portion.

[0043] Furthermore, in order to achieve more efficient solid-liquid separation, while preventing breakage of the seal belt 8 as described above, it is desirable that the air permeability of the seal belt 8 be higher than the air permeability of the filtration belt 1 and be within the range of 5 cc/cm.sup.2/min to 1000 cc/cm.sup.2/min. When the air permeability of the seal belt 8 is equal to or less than the air permeability of the filtration belt 1 or less than 5 cc/cm.sup.2/min, there is a likelihood that the seal belt 8 is likely to be clogged, and it is difficult to efficiently separate the liquid content from the object P to be processed. On the other hand, if the air permeability of the seal belt 8 exceeds 1000 cc/cm.sup.2/min, since the strength of the seal belt 8 is impaired and breakage is likely to occur, and the object P to be processed leaks through the seal belt 8 together with the liquid content due to the ventilation, the recovery rate of the object P to be processed decreases.

[0044] Moreover, it is desirable that the air permeability of the squeezing belt 15 be equal to or greater than 3000 cc/cm.sup.2/min. If the air permeability of the squeezing belt 15 is less than 3000 cc/cm.sup.2/min, it is difficult for the ventilation gas A to pass through the squeezing belt 15, clogging is likely to occur in the squeezing belt 15, and there is a likelihood that it is not possible to efficiently dehydrate the liquid content, which is separated from the object P to be processed, from the seal belt 8 via the squeezing belt 15.

[0045] Furthermore, it is desirable that the squeezing belt 15 has strength to be broken by a tensile stress (tension) of 20 N/mm or more when the tensile stress is applied. By preventing an occurrence of breakage in the squeezing belt 15 up to such a high tensile stress, since the ejection pressure of the ventilation gas A can be increased, more efficient solid-liquid separation can be promoted.

[0046] Here, in order to ensure strength in the squeezing belt 15 such that breakage does not occur even under such a high tensile stress, it is desirable that a warp of the squeezing belt 15 be a polyarylate fiber or a polyparaphenylene benzobisoxazole fiber. Since a high tensile stress does not act on the weft, there is no particular limitation as long as it has a normal strength.

[0047] Furthermore, it is desirable that the filtration belt 1 be at least one kind of a woven fabric of multifilament, a woven fabric of monofilament, a woven fabric of a spun table, or a woven fabric obtained by combining at least two kinds of the multifilament, the monofilament, and the spun table. Therefore, even if the ejection pressure of the ventilation gas A is increased as described above, it is possible to prevent damage to the filtration belt 1 due to the ejection of the ventilation gas A. Accordingly, the frequency of replacement of the filtration belt 1 can be reduced, and it is possible to more reliably perform efficient solid-liquid separation. Further, since the frequency of replacement of the filtration belt 1 is reduced, it is also economical.

INDUSTRIAL APPLICABILITY

[0048] By applying the solid-liquid separation device of the present invention to this field, it is possible to prevent breakage of the seal belt even when performing the solid-liquid separation for a long time, while suppressing the occurrence of wrinkles in the seal belt.

REFERENCE SIGNS LIST

[0049] 1 Filtration belt [0050] 2, 14, 16 Roll [0051] 2A Driving roll [0052] 3 Supply unit [0053] 4 Filtration unit [0054] 7 Separation roll [0055] 8 Seal belt [0056] 9 Penetration hole [0057] 10 Ventilation gas chamber [0058] 11 Ventilation Pipe [0059] 13 Automatic valve [0060] 15 Squeezing belt [0061] 17 Squeezing belt tensioning device [0062] A Ventilation gas [0063] P Object to be processed [0064] F Running direction of filtration belt 1 [0065] G Running direction of seal belt 8 [0066] H Running direction of squeezing belt 15 [0067] T Rotational direction of separation roll 7