JP3347018B2 - Centrifugal filtration method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal filtration method for separating a slurry into a liquid component and crystals, and a centrifugal filtration device used for performing the method.

[0002]

2. Description of the Related Art In a chemical plant or the like, a solid-liquid separation step (a step of separating a solid and a liquid) for obtaining a crystal by separating a liquid component from a slurry (a stock solution containing crystals) in a process of manufacturing a product is performed. Often there are. Further, following the solid-liquid separation step, a washing step of washing the crystals with a washing liquid and a drying step of drying the washed crystals are often performed in combination, and a centrifugal filtration device is used as an apparatus for performing these steps. Have been.

In general, a centrifugal filtration device includes a casing having an openable and closable cover, a cylindrical peripheral wall formed with a large number of through holes, a bottom wall closing one axial end of the peripheral wall, and the peripheral wall. A basket rotatably supported in the casing having an annular end wall protruding inward in the radial direction from the inner periphery of the other end in the axial direction, a rotation drive device for rotating the basket, A slurry supply device that supplies slurry into the basket and a crystal scraping device that scrapes crystals formed on the inner periphery of the peripheral wall of the basket are provided. Separates the slurry into liquid and crystals.

When a solid-liquid separation step is performed by a centrifugal filtration device, crystals are not squeezed as in the case of using a filter type filtration device, and appropriate voids are formed in the crystal structure. The washing liquid can be uniformly permeated into the inside, so that the crystals can be sufficiently washed in a short time, and high-quality crystals can be obtained. In the centrifugal filtration device, the crystal structure does not become dense as in the case of using a filter-type filtration device, so that the crystal can be dried in a relatively short time.

As described above, when a centrifugal filtration device is used,
Not only can the crystals be washed efficiently and uniformly, but also the obtained crystals can be dried in a short time, so that high-quality crystals with few impurities can be efficiently obtained.

[0006]

As described above, the centrifugal filtration apparatus has a number of advantages. However, since the crystals are formed in a basket-shaped basket, the obtained crystals cannot be collected. There is a problem that it is not easy. In particular, when the basket is placed in a casing having a closed structure to perform the solid-liquid separation treatment in order to prevent the contamination of impurities, a special device is required for collecting crystals.

[0007] In order to recover crystals from the basket of the centrifugal filtration device, a method of inserting a crystal recovery suction tube connected to a vacuum suction device into the basket and suctioning crystals through the suction tube is adopted. It is convenient. By using such a suction tube, it is possible to collect crystals even when the basket is arranged in a casing having a closed structure.

However, simply inserting the suction tube into the basket makes it difficult to collect all the crystals in the basket, and inevitably causes the crystals to remain in the basket.

The inventor of the present invention has provided a groove formed in the inner periphery of a basket on the bottom wall of a basket as shown in Japanese Patent Publication Nos. 60-28553 and 62-44982. Thus, a centrifugal filtration device has been proposed in which crystals scraped off by a scraping device and dropped into grooves in the bottom wall of the basket are suctioned and discharged by a suction tube for crystal recovery. According to this centrifugal filtration device, the crystal recovery rate can be increased, but it is difficult to collect all of the scraped crystals in the groove. Cannot be avoided.

Therefore, the applicant of the present application has previously filed Japanese Patent Application No.
No. 74983, when collecting crystals, the center axis of the basket is inclined at a certain angle with respect to the horizontal direction so that the bottom wall of the basket faces obliquely downward, thereby improving the crystal recovery rate. The proposed centrifugal filtration device. In this centrifugal filtration device, after drying the crystal in the basket, the tip of the suction pipe for crystal recovery is made to enter the crystal to suck the crystal, and finally, the tip of the suction pipe is inclined to the peripheral wall of the basket. The crystal collected at the corner is sucked by being displaced to a position close to the corner between the bottom of the section and the bottom wall of the basket.

According to this centrifugal filtration device, the recovery rate of the crystal can be improved, but since no measures have been taken to seal the opening of the basket, the crystal is dried and the crystal is sucked. During the recovery, it was found that there was a problem that the dried and finely powdered crystals were scattered and leaked from the opening of the basket to the outside, and the leaked crystals adhered to the periphery of the basket.

An object of the present invention is to provide a centrifugal filtration method and a centrifugal filtration method capable of improving the recovery rate of crystals and eliminating the possibility that dried and fine crystals leak from the basket to the outside. An object of the present invention is to provide a centrifugal filtration device used for carrying out the method.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a cylindrical peripheral wall having a plurality of transmission holes formed therein, a bottom wall closing one axial end of the peripheral wall, and an axial other end of the peripheral wall. The slurry is subjected to centrifugal filtration using a centrifugal filtration device including a basket having an annular end wall protruding radially inward from the inner periphery of the slurry and a rotary driving device for driving the basket to rotate. Is separated into liquid and crystals to form crystals on the inner periphery of the basket, a crystal scraping process of scraping off the crystals formed on the inner periphery of the basket, and drying the crystals in the basket The present invention relates to a centrifugal filtration method in which a drying step and a crystal recovery step of sucking and recovering crystals scraped off from the inner periphery of the basket by a crystal recovery suction tube inserted into the basket are performed.

According to the present invention, a rotary seal member which abuts against the end wall of the basket from the outside and rotates together with the basket while keeping the opening on the inner peripheral side of the end wall closed is provided on the end wall. Is provided so that it can be retracted to a position where it does not abut.

At least in the crystal recovery step, the basket is supported so that the central axis of the basket is inclined at a certain angle with respect to the horizontal direction, and the bottom wall of the basket faces obliquely downward.

In the solid-liquid separation step, the rotary seal member is retracted, and when performing the crystal scraping step, the drying step and the crystal recovery step, the rotary seal member is brought into contact with the end wall of the basket. The opening on the inner peripheral side of the end wall of the basket is kept closed.

In the crystal recovery step, the tip of the crystal recovery suction tube enters the crystal while rotating the rotary seal member together with the basket while the rotary seal member is in contact with the end wall of the basket. And aspirate the crystals,
Finally, the tip of the suction tube is displaced to a position close to the corner between the lowermost part of the inclined peripheral wall of the basket and the bottom wall of the basket, and the crystals collected at the corner are suctioned. to recover.

A centrifugal filtration device according to the present invention comprises a casing having an openable / closable cover, a cylindrical peripheral wall having a large number of permeation holes, and a bottom wall closing one axial end of the peripheral wall. A basket rotatably supported in the casing having an annular end wall protruding inward in the radial direction from the inner circumference of the other end in the axial direction of the peripheral wall, and rotatably driving the basket; A rotation driving device, a slurry supply device for supplying slurry into the basket, a crystal scraping device for scraping crystals formed on the inner periphery of the peripheral wall of the basket, and a crystal in the basket in the basket. And a crystal recovery device for suctioning and recovering the crystal with the inserted crystal recovery suction tube.

According to the present invention, the fixed member is supported by the cover of the casing and is disposed concentrically through an annular gap inside the inner peripheral surface of the end wall of the basket when the cover is closed. A lid, a linear drive supported by the cover of the casing, and a cover disposed between the cover and the end wall of the basket when the cover of the casing is closed, and driven by the linear drive to drive the basket; A seal supporting member that is linearly displaced along the center axis of the basket between an advanced position set near the end wall and a retracted position set close to the casing cover; When the seal support member is in the advanced position, it is kept free from the end wall of the basket when the seal support member is in the retracted position and the seal support member is in the advanced position. Abuts the end wall of the basket is provided a rotary sealing member annular keep the closed gaps annular formed between said end wall and the stationary lid.

The rotary seal member is provided so as to rotate together with the basket while being in contact with the end wall of the basket. That is, by aligning the rotation center axis of the rotating seal member with the center axis of the basket, the basket can be rotated together with the rotating seal member in contact with the end wall of the basket.

In addition, the basket is supported so that at least when the crystal is recovered by the crystal recovery apparatus, the central axis thereof is obliquely inclined and the bottom wall is directed obliquely downward.

Here, to support the basket "at least when the crystal is recovered by the crystal recovery apparatus so that the central axis is inclined obliquely and the bottom wall is directed obliquely downward" means that the basket is supported. The basket support device may be configured so as to always maintain such a tilted state, and the support mechanism is configured so that the tilt angle of the basket can be adjusted, and at least when collecting crystals. It is intended that the basket may be inclined as described above.

The suction pipe for crystal recovery is formed in a shape having a swirling part which swirls in the basket, and the lowermost part of the peripheral wall part of the basket and the bottom wall of the basket in which the tip part of the swirling part is inclined. Between the final suction position, which is in a state close to the corner between the two parts, and the retreat position, in which the tip is retracted inward from a position corresponding to the inner periphery of the opening of the basket. It is provided as follows.

As described above, if a rotary seal member is provided to close the opening on the inner peripheral side of the end wall of the basket while abutting on the basket and rotating with the basket,
When drying the crystals in the basket and collecting the crystals, it is possible to prevent the dried and fine crystals from leaking out of the basket.

It is not preferable to rotate the rotating seal member at a high speed in order to maintain the sealing performance. However, the basket is not rotated at a high speed in the drying step and the crystal recovery step. There is no problem if the member is kept in contact with the end wall of the basket.

Since the rotary seal member can be retracted to a position where it does not come into contact with the end wall of the basket, when the basket is rotated at a high speed in a solid-liquid separation step or the like, the rotary seal member is retracted. By doing so, it is possible to prevent the rotation of the basket from being hindered.

[0027]

FIG. 1 shows an example of the configuration of a centrifugal filtration apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an installation base, 2 denotes an installation base, and bolts and the like are provided on the installation base 1. Is a base frame fixed by The upper surface 2a of the base frame 2 is an inclined surface inclined by 10 to 30 degrees with respect to the horizontal direction, and the base plate 3 is fixed on the inclined surface. The lower ends of frame plates 4 and 5 arranged so that the base plate 3 and the plate surface are orthogonal to each other are fixed to the base plate 3, and the bearing devices 6 are supported by the frame plates 4 and 5. The bearing device 6 accommodates ball bearings 6A and 6B in a cylindrical housing 6a, and the rotating shaft 7 is rotatably supported by these ball bearings.

The frame plate 4 has an annular flange plate 8
Is fixed, and the cover 9 of the casing is openably and closably connected via a hinge (not shown). The casing cover 9 has a cylindrical peripheral wall portion 9a that can be aligned with the flange plate 8, an outer flange 9b formed at one axial end of the peripheral wall portion 9a, and the other axial end of the peripheral wall portion 9a. An end wall 9c to be closed and an inner flange 9d formed on the inner periphery of the peripheral wall 9a while being positioned inside the end wall 9c.
And a peripheral wall 9a at the center of the end wall 9c.
And a circular opening 9e sharing a central axis. A disk-shaped flange plate 9f forming a part of the cover 9 is attached so as to close the opening 9e.

The casing cover 9 has a hinged position (not shown) as a center, a closed position where the peripheral wall portion 9a comes into contact with the flange plate 8 as shown in the figure, and a central axis of the peripheral wall portion 9a which corresponds to the rotating shaft 7. Can be rotated between an open position which is in a state orthogonal to the center axis of. A packing (not shown) is provided between the flange 9b of the cover 9 and the flange plate 8, and the flange 9b is fastened to the flange plate 8 by fastening means such as bolts with the cover 9 positioned at the closed position. Thereby, the joint between the flange 9b of the casing cover 9 and the flange plate 8 can be kept airtight and liquidtight. In this example,
The cover 9, the frame plate 8, and the flange plate 4 form a casing 10, and the frame plate 4 forms a bottom of the casing.

One end of the rotating shaft 7 supported by the bearing device 6 is introduced into the casing 10 through a seal member 11 attached to the frame plate 4, and the other end is led out from the end of the bearing device 6. .

At one end of the rotating shaft 7, a basket-shaped basket 1 is provided.
2 are installed. The basket 12 includes a peripheral wall portion 12a, a bottom wall portion 12b provided so as to close one end of the peripheral wall portion 12a in the axial direction, and a radially inward portion from the inner periphery of the other axial end of the peripheral wall portion 12a. It is formed in a cage shape having an annular end wall 12c provided so as to protrude. In the illustrated example, the outer flange 12 is attached to the outer periphery of the peripheral wall portion 12a of the basket 12 near the other end in the axial direction.
d is provided, and the end wall 12c is formed by an annular plate detachably attached to the outer flange 12d by a bolt or the like.
Is configured. An infinite number of transmission holes are formed in the peripheral wall portion 12a of the basket in a state of being uniformly dispersed throughout the peripheral wall portion. A filter 13 is arranged on the inner periphery of the peripheral wall portion 12a of the basket, and the filter is fixed to the inner periphery of the basket by an appropriate fixing means.

The basket 12 is inserted into the casing 10 with its central axis aligned with the central axis of the casing 10 and the central axis of the bearing device 6 and with its bottom wall 12b facing the frame plate 4. A boss 12 e, which is arranged and fixed to the outer surface of the central portion of the bottom wall portion 12 b, is fixed to one end of the rotating shaft 7. Therefore, basket 1
2 is that the center axis is always 10 degrees to 30 with respect to the horizontal direction.
The bottom wall 12b is tilted at an angle and is in a state of facing obliquely downward.

On the inner surface of a disk-shaped flange plate 9f attached so as to close an opening 9e formed at the center of the end wall 9c of the casing cover 9, a peripheral wall 9a of the casing cover is provided. A disc-shaped fixed lid 14 arranged concentrically is attached via a cylindrical connecting cylinder 15. The connecting cylinder 15 and the fixed lid 14 are joined and integrated by welding or the like. The disk-shaped fixed lid 14 has an outer diameter smaller than the inner diameter of the end wall 12c of the basket 12, and when the cover 9 is arranged at the closed position (when closed), the fixed lid 14 The fixed lid 14 and the basket end wall 12c are arranged concentrically with the basket 12 inside the inner peripheral portion of the end wall 12c.
A gap g1 is formed between the inner peripheral portion and the inner peripheral portion.

The inner collar 9d of the casing cover 9
Is provided so as to concentrically surround the outer peripheral portion of the end wall 12c of the basket 12 from the outside when the cover 9 is located at the closed position, and to cope with the inner periphery of the inner flange portion 9d and the end of the basket. A minute gap g2 is formed between the outer wall of the wall 12c and the outer wall.

The flange plate 9f is further provided with a slurry supply device 20 for supplying slurry into the basket,
A crystal scraping device 21 for scraping crystals formed on the inner periphery of the second peripheral wall portion 12a, a heating device 22 for supplying heat into the basket for drying the crystals in the basket, and a crystal forming device formed in the basket. Crystal recovery device 2 for recovering crystals
3 and a cleaning liquid supply device 24 are attached.

The slurry supply device 20 includes a liquid supply pipe 20A which is inserted into the basket through the flange plate 9f and the fixed lid 14 in a gas-tight and liquid-tight manner.
The end 20a located in the basket A is bent so as to face the peripheral wall 12a side of the basket. An end 20b of the liquid supply pipe 20A located outside the casing is connected to a slurry supply pump or tank through an electromagnetic valve (not shown) and piping. A slurry supply device 2 that supplies slurry into the basket 12 by a liquid supply pipe 20A and an electromagnetic valve (not shown) connected to the liquid supply pipe.
0 is configured.

The crystal scraping device 21 is inserted into the basket 12 through the flange plate 9f and the fixed cover 14, and is rotatably supported by a bearing 21A. The drive shaft 21B is rotatably supported by an arm 21C. And a position corresponding to the inner peripheral portion of the end wall 12c of the basket, which is in a state of being close to the filter 13 disposed on the inner peripheral portion of the peripheral wall portion 12a of the basket with the rotation of the drive shaft 21B. A scraping blade 21D that pivots between a retracted position that is retracted radially inward and a scraping blade driving device that drives the drive shaft 21B to rotate the scraping blade 21D (not shown). )).

When the basket 12 is rotated to supply slurry into the basket, and when the basket 12 is rotated at a high speed to perform liquid removal, the scraping blade 21D is held at the retracted position. When the crystal formed on the inner periphery of the peripheral wall portion 12a of the basket is scraped off, the scraping blade 21D is gradually advanced into the crystal. The scraping blade 21D is advanced to an approach limit position where the scraper blade 21D finally comes close to the filter 13 arranged on the inner periphery of the basket.

The illustrated heating device 22 comprises an L-shaped pipe 22A inserted into the basket 12 in a state where the flange plate 9f and the fixed lid 14 are air-tightly and liquid-tightly penetrated. A hot water flow path for reciprocating hot water is formed as shown by an arrow in the drawing. At the end of the pipe 22A located outside the casing, there is an inlet 22a for hot water.
And an outlet 22b for low-temperature water, so that high-temperature water is supplied to the inlet 22a from a boiler (not shown). The low-temperature water flowing out of the outlet 22b is returned to the boiler through a pipe (not shown) and reheated.

The crystal recovery device 23 is provided with a crystal recovery suction tube 2.
3A and a suction pipe driving device (not shown) for driving the suction pipe. Crystal recovery suction tube 23
A is provided so as to extend in parallel with the axis of the basket 12, and penetrates a flange plate 9f forming a part of the cover 9 at a position eccentric with respect to the center axis of the basket 12, and is rotatably supported by the bearing 23B. The straight pipe portion 23a and the rear end portion thereof are connected to the basket-side end portion of the straight pipe portion, and the front end portion 23b1 is formed in a curved shape so as to be directed to the peripheral wall portion 12a side of the basket 12. And a revolving portion 23b that revolves in the basket with the rotation of. The crystal recovery suction tube 33A is connected to a vacuum suction device (not shown).

Revolving part 23b of suction pipe 23A for crystal recovery
As shown by a solid line in FIG. 1, the tip 23b1 is located at the lowermost portion of the peripheral wall portion of the basket (more precisely, the lowermost portion of the filter 13) while maintaining the tip 23b1 close to the inner surface of the bottom wall portion 12b of the basket. 1) between the final suction position in which it is directed to the vicinity and the retreat position in which the swirling portion 23b is oriented substantially horizontally along the radial direction of the basket as shown by the chain line in FIG. It is provided to
When the revolving portion 23b reaches the final suction position, the tip 23b1 of the revolving portion becomes the lowermost part of the peripheral wall 12a of the basket 12 (the lowermost part of the filter 13) and the bottom wall 12b of the basket.
Between the end portion 12b of the basket and the end 23b1 of the basket when the retreat position is reached.
The shape and length of the turning portion 23b are set so that the turning portion 23b is retracted inward from a position corresponding to the inner peripheral portion of the turning portion 23c.

When the basket 12 is rotated to supply slurry into the basket, and when the basket is rotated at a high speed to perform liquid removal, the swirling portion 23b of the suction pipe 23A is retracted as indicated by a chain line in FIG. Held in position. When the crystals in the basket are collected, the turning part 23b is rotated to the final suction position.

The cleaning liquid supply device 24 includes a cleaning liquid supply pipe 24a inserted into the basket 12 through the flange plate 9f forming a part of the cover 9 of the casing and the fixed lid 14 in a liquid-tight and air-tight manner. And a spray nozzle 24b attached to the tip of the supply pipe. Cleaning liquid supply pipe 2
The end of 4a located outside the casing is connected to a supply source (pump, tank, etc.) of the cleaning liquid (usually water) via an electromagnetic valve (not shown) and a predetermined pipe. The cleaning liquid supply device 24 is configured by the cleaning liquid supply pipe 24a, the nozzle 24b, and an electromagnetic valve (not shown).

In the present invention, a seal mechanism 30 for sealing an annular gap g1 formed between the inner peripheral portion of the end wall 12c of the basket 12 and the outer peripheral portion of the fixed lid 14 is provided.
Is provided. FIG. 2 shows a configuration example of the seal mechanism 30.

The sealing mechanism 30 shown in FIG. 2 is configured such that the linear drive device 31 supported by the casing cover 9 and the cover 9 and the end wall 12c of the basket 12 when the casing cover 9 is closed. Between the forward position set near the end wall of the basket 12 driven by the linear driving device 31 and the position close to the cover 9 of the casing (the position close to the flange plate 9f in the illustrated example). An annular seal support member 32 linearly displaced along the central axis of the basket 12 between the set retreat position and the seal support member 32 rotatably supported by the seal support member 32, and the seal support member 32 is at the forward position. An annular rotary seat which abuts against the end wall 12c of the basket 12 to close an annular gap g1 formed between the end wall 12c and the fixed lid 14. And a member 33.

More specifically, in the illustrated example, the outer peripheral surface of the connecting cylinder 15 to which the fixed lid 14 is attached is fixed to the fixed lid 14.
The connecting tube 15 is provided so as to be located on the same plane as the outer peripheral surface of the connecting member 15, so that no step is formed on the outer periphery of the joint portion between the connecting tube 15 and the fixed lid 14.

The connecting cylinder 15 also serves as a guide means for the seal supporting member 32, and the annular seal supporting member 32 is slidably fitted on the outer periphery of the connecting cylinder 15. The seal support member 32 has an L-shaped annular body 32a having a cylindrical portion 32a1 and an annular flange portion 32a2 protruding radially outward from one axial end of the cylindrical portion 32a1. An annular bearing pressing plate 32b is in contact with the end surface of the cylindrical portion 32a1 at the other end in the axial direction.
The annular body 32a is disposed with its flange 32a2 facing the basket 12 side.
The inner ring 35a of the bearing 35 is fitted on the outer periphery of 2a1. The bearing pressing plate 32b has a portion that comes into contact with the end surface of the inner ring 35a of the bearing. The pressing plate 32b is fastened to the annular body 32a by bolts 34, and the inner ring of the bearing 35 is fixed to the seal support member 32. .

The linear driving device 31 includes the seal supporting member 3
Any linear displacement device may be used as long as it can linearly displace 2. In the illustrated example, the linear drive device includes an air cylinder 31A, and a small-diameter portion 31a formed at the tip of the cylindrical portion of the air cylinder 31A is provided. Is fitted into a through hole 901 provided in the flange plate 9f via a sleeve-shaped sealing material 36. A screw 31b1 is formed at the tip of the piston rod 31b of the air cylinder 31A, and this screw is screwed into a screw hole provided in the bearing pressing plate 32b.
The piston rod 31b is connected to the seal support member 32.

The seal support member 32 is an air cylinder 31
Driven by A (linear drive), the basket 1
The basket is linearly displaced along the central axis of the basket between a forward position set near the second end wall 12c and a retreat position set close to the cover 9 of the casing. In order to smoothly displace the seal support member 32, the air cylinder 31 constituting the linear drive device 31
A is provided at least three (preferably 4 to 6), and the at least three air cylinders are arranged at equal intervals along the circumferential direction of the seal support member 32.

On the outside of the bearing 35, a ring 37a having an L-shaped cross section having a cylindrical portion 37a1 and an annular protruding portion 37a2 protruding radially inward from one axial end of the cylindrical portion.
Are arranged, and an outer ring 35b of a bearing is fitted to the inner periphery of the cylindrical portion of the ring 37a. Cylindrical part 37 of ring 37a
The bearing holding plate 37b is brought into contact with the end face on the other end side in the axial direction of a1, and the bearing holding plate 37b is
7a. Ring 37a and bearing holding plate 37
and b, a rotating body 37 is formed, and the outer ring 35b of the bearing is fixed between the holding plate 37b and the protruding portion 37a2 of the ring 37a in a state of being sandwiched therebetween.

Annular body 32 constituting seal support member 32
The oil seals 39 and 40 are fitted in grooves formed on the outer periphery of a and the outer periphery of the bearing holding plate 32b, respectively. With these oil seals, the seal support member 32
The lubricating oil of the bearing 35 is prevented from leaking from the gap between the rotating body 37 and the rotating body 37.

The rotating member 37 includes an annular rotating seal member 3.
3 is attached. The rotary seal member 33 is in contact with the basket-side end face of the rotating body 37 and is fastened to the rotating body 37 by a bolt 41 in an annular flange portion 33a.
And a protruding portion 33b protruding from the inner peripheral portion of the flange portion 33a to the basket side. The outer periphery of the protruding portion 33b has a taper whose diameter decreases toward the tip end (basket side). It is attached. The protruding portion 33b of the rotary seal member 33 includes a cylindrical portion 33b1 continuous with the flange 33a and an inner flange portion 33b2 protruding radially inward from the tip of the cylindrical portion 33b1.
The inner diameter of b2 is set slightly larger than the outer diameter of the fixed lid 14, and a minute gap g3 is formed between the inner peripheral part of the inner flange 33b2 and the outer peripheral part of the fixed lid 14. An annular packing 42 is fitted on the inner periphery of the protrusion 33b of the rotary seal member.

The seal support member 32 of the rotary seal member 33
A portion from the inner periphery of the side surface is cut to form a step portion 33c having a predetermined depth, and a packing holding plate 43 is in contact with an axial end surface of the step portion 33c. The holding plate 43 is fastened to the rotary seal member 33 by bolts 44 and the packing 4
2 is fixed while being sandwiched between the holding plate 42 and the inner flange portion 33b2. The packing 42 is provided so as to be in sliding contact with the outer peripheral surfaces of the fixed lid 14 and the connecting cylinder 15. The packing 42 allows the rotating seal member 33 to move between the outer peripheral surfaces of the fixed lid 14 and the connecting cylinder 15. A seal is provided.

The maximum radial dimension d of the projection 33b of the rotary seal member 33 is slightly smaller than the radial dimension of the gap g1 between the inner circumference of the end wall 12c of the basket and the outer circumference of the fixed lid 14. Is set, and the protruding portion 33b is
It is designed to be easily inserted inside.

A packing 33d made of a rubber plate or the like is provided on the basket side surface of the flange portion 33a of the rotary seal member 33.
When the seal support member 32 is moved to the forward position by the linear drive device 31, the flange portion 33a of the rotary seal member 33 comes into contact with the end wall 12c of the basket via the packing 33d. , The end wall 1
G1 (the end wall 12)
c on the inner peripheral side).

In FIG. 2, 16 is a bolt for fastening a flange plate 9f forming a part of the casing to the end wall 9c, 1
Numeral 7 is a packing for maintaining the air-tightness and liquid-tightness of the joint between the flange plate 9f and the end wall 9c.

On the base plate 3 shown in FIG. 1, a motor 50, which is a driving source for rotating the basket 12, is mounted, and a pulley 51 is mounted on a rotating shaft 50a of the motor. A pulley 52 is attached to the other end of the rotating shaft 7 led out from an end of the bearing device 6.
A belt 53 is stretched around 1 and 52. Electric motor 5
The rotation drive device 55 that rotates the basket 12 via the rotation shaft 7 is constituted by the 0, the pulleys 51 and 52, and the belt 53.

The base plate 3 is also provided with a cover 56 for covering the bearing device 6 and the rotary drive device 55.

In the illustrated example, the casing cover 9
A drain pipe connection 9g, a drain pipe connection 9h, and a decompression device connection 9i for connecting a decompression device such as a vacuum pump for decompressing the inside of the casing are attached to the peripheral wall 9a.

The drain pipe connection 9g is for connecting a drain pipe for discharging the liquid discharged from the basket to the outside. The drain pipe connecting portion 9h is a portion for connecting a drain pipe for discharging the liquid that has entered the gap G between the inner flange portion 9d of the casing cover 9 and the end wall 9c through the gap g2 to the outside. , Cover 9
The inner collar portion 9 faces downward when the is positioned at the closed position.
It is provided so that a gap G between d and the end wall 9c communicates with the outside.

The pressure reducing device connecting portion 9i is provided so as to open upward when the cover 9 is located at the closed position, and is connected to a pressure reducing device such as a vacuum pump through a pipe (not shown).

Next, a series of processes performed using the above-mentioned centrifugal filtration device will be described with reference to FIGS.

When the slurry is separated into liquid and crystal using the above-mentioned centrifugal filtration apparatus, the casing cover 9 is closed as shown in FIG.
The suction pipe 23 for crystal recovery is positioned at the retreat position indicated by the chain line in FIG. 1, and the scraping blade 21D is positioned at the retreat position set inside the position corresponding to the inner peripheral portion of the end wall of the basket. Keep it. In addition, the piston rod of the air cylinder 31 a constituting the linear drive device 31 is retracted to position the seal support member 32 at the retracted position, and the rotary seal member 33 is kept away from the end wall 12 c of the basket 12. In this state, a solid-liquid separation step including a liquid supply step and a liquid removal step is performed.

In the liquid supply step, first, the electric motor 50 is driven to rotate the basket 12 at a rotation speed suitable for liquid supply.
Since the rotary seal member 33 is separated from the end wall 12c of the basket, the speed of the basket 12 is increased without any trouble. After the rotation speed of the basket reaches a predetermined value, the electromagnetic valve (not shown) of the slurry supply device 20 is opened, and the slurry S is introduced into the basket 20 through the slurry supply pipe 20A as shown in FIG. Supply. During the liquid supply process, when it is detected from the output of the liquid level detector (not shown) that the liquid level of the slurry has reached the limit position, the supply of the slurry into the basket 12 is interrupted. The liquid component in the slurry is discharged out of the basket through the filter by the centrifugal force generated by the rotation of the basket 12, and the crystals C contained in the slurry accumulate on the inner periphery of the filter arranged inside the peripheral wall of the basket 12. To go. Liquid L discharged out of basket
Flows down through the casing 10 and is discharged from the drain pipe connection portion 9g through a valve (not shown) and a drain pipe.

When it is detected that liquid removal has progressed and the liquid level has dropped to a predetermined position, slurry supply is resumed,
When it is detected that the liquid level has reached the limit position, the supply of the slurry is stopped again.

When the above operation is repeated, the thickness of the crystal C layer formed on the inner periphery of the basket increases,
As the thickness of the crystal layer increases, the time required for drainage increases. When the thickness of the layer of the crystal C is sufficiently large and a state in which a decrease in the liquid level is not detected within a predetermined time occurs, the supply of the slurry into the basket is stopped,
The liquid supply step ends. After the liquid supply step is completed, the basket 12 is accelerated to the rotation speed at the time of liquid removal, and the liquid is drained while maintaining the rotation speed for a predetermined liquid removal time experimentally determined in advance. Thereby, a layer of cake C is formed on the inner periphery of the basket as shown in FIG.

After the elapse of the liquid removing time, a washing step of washing the crystals in the basket is performed. In this cleaning step, the electromagnetic valve of the cleaning liquid supply device 24 is opened while rotating the basket at a rotation speed suitable for cleaning, and the cleaning liquid W flows into the cleaning liquid supply pipe 24 as shown in FIG. The cleaning liquid W is sprayed from the nozzle 24b toward the peripheral wall of the basket. The crystal C is washed with this washing liquid. After the elapse of a certain washing time, the basket is accelerated to the rotation speed for removing liquid, and the washing liquid contained in the crystal is separated from the crystal.

After the completion of the cleaning process, the basket is temporarily stopped, and the air cylinder constituting the linear drive device 31 is driven to move the seal support member 32 to the forward position. , And the flange portion 33a of the rotary seal member is connected to the end wall 1 of the basket via the packing 33d (see FIG. 2).
2c. Thereby, the end wall 1 of the basket
The gap g1 between 2c and the fixed lid 14 is closed to prevent solids from leaking from inside the basket.

In this state, a crystal scraping step of scraping the crystals C formed in the basket 12, a drying step of drying the scraped crystals, and a crystal collecting step of collecting crystals from the basket are performed.

In the crystal scraping step, while the basket 12 is rotated at a low speed, the driving device of the crystal scraping device 21 is driven to move the scraping blade 21D to the peripheral wall of the basket 12 as shown in FIG. The crystal C is scraped off by rotating to the side of the part 12a, thereby causing the scraping blade 21D to enter the crystal C. After the crystals C are scraped off, a drying step is performed.

In this drying step, as shown in FIG. 4B, warm water H is supplied to the heating device 22 to heat the inside of the basket 12. In the drying step, with the valve (not shown) connected to the drain pipe connection part 9g and the drain pipe connection part 9h closed and the casing 10 sealed, the suction pipe 23A in which the revolving part 23b is in the retracted position and the decompression The inside of the basket 12 and the casing 10 through the device connection 9i
Reduce the pressure inside.

As described above, when the inside of the basket is heated by the heating device 22 while rotating the basket 12,
The washing liquid contained in the crystals in the basket evaporates and the crystals dries. Since the basket 12 has its central axis inclined at 10 to 30 degrees with respect to the horizontal direction, the crystal to be dried is lifted upward from the lower part of the peripheral wall of the basket with the rotation of the basket. After turning over and falling. As described above, since the crystal is inverted as the basket rotates, the crystal is uniformly exposed to heat during the inversion. Therefore, the crystals can be efficiently dried in a short time.

In the drying step, the scraping blade 21D
It may be located at the approach limit position or may be located at the evacuation position.

The pressure in the basket is reduced by the suction tube 23A.
May be performed only by the decompression device connected to the decompression device connection portion 9i in a state where the electromagnetic valve provided in the device is closed.

As described above, if the inside of the casing 10 is evacuated when the crystal is dried, the evaporation of the liquid in the crystal is promoted. Also, the crystals can be dried in a short time, and the amount of heat can be saved. Further, since the temperature in the basket at the time of drying can be lowered, it is possible to prevent the crystal from being deteriorated by heat. Further, when the inside of the casing is evacuated, oxygen in the basket can be eliminated or reduced at least, so that the crystal can be prevented from being oxidized and deteriorated.

The drying step ends when a certain drying time has elapsed. Since the dried crystals are in a smooth state and have a high fluidity, they are gathered at the lower part of the basket 12 as shown in FIG.

After the drying step is completed, the crystal recovery step is performed while rotating the basket 12 at a low speed. In the crystal recovery step, the vacuum suction device connected to the crystal recovery suction pipe 23A is operated, and the rotating part 23b of the crystal recovery suction pipe 23A is slowly rotated to the final suction position side by a driving device (not shown). The tip of 23b enters the crystal, and the crystal is suctioned and collected.

As shown in FIG. 4D, when the swirling portion 23b reaches the final suction position, the turning portion is stopped, and the collection of the crystal is continued. Since the dried crystals have fluidity and are collected at the bottom of the basket where the swirling portion 23b is directed by the rotation of the basket 12, almost all the crystals in the basket are sucked from the tip of the swirling portion 23b. Can be collected.

When the collection of crystals is completed, the basket is stopped, and a series of steps is completed. When a series of steps from the solid-liquid separation step to the crystal recovery step is performed a plurality of times to process one lot of slurry, after the crystal recovery step is completed, the basket is accelerated and the next solid-liquid Move to the separation step.

When the processing of one lot of the slurry is completed, the basket is stopped, the cover 9 of the casing is opened, and the inside of the casing and the basket are washed.

In the drying step and the crystal recovery step, when the dried crystal becomes fine powder, the crystal flies in the basket and flows in the basket. If this finely divided crystal leaks out of the basket, the inside of the casing is soiled and the cleaning operation inside the casing becomes troublesome. However, in the present invention, the opening on the inner peripheral side of the end wall of the basket is provided by the rotating seal member. Since the drying step and the crystal recovery step are performed with the portion (gap g1) closed, it is possible to prevent the finely divided crystals from leaking out of the basket and fouling the inside of the casing.

It is preferable that the above series of steps be performed automatically. In order to perform the above steps automatically, the supply of a predetermined amount of slurry into the basket while rotating the basket is performed with the rotary seal member 33 retracted so as not to contact the end wall of the basket. A liquid process, and a liquid removing process in which the rotating seal member 33 is kept in a retracted state so as not to contact the end wall of the basket, and the basket is kept in a rotated state to remove the liquid component in the crystal. A cleaning step of maintaining the seal member 33 in a retracted state so as not to contact the end wall of the basket and supplying a cleaning liquid into the basket while the basket is rotated to wash the crystals; A crystal that scrapes the washed crystal while rotating the basket in a state where the opening 33 on the inner peripheral side of the basket end wall is closed by contacting the basket 33 with the basket end wall. In the dropping step and in a state where the rotary seal member 33 is in contact with the end wall of the basket and the opening on the inner peripheral side of the end wall of the basket is closed, heat is supplied into the basket while rotating the basket. A drying step of drying the crystals by rotating the rotating pipe and a rotating section of the suction pipe for crystal recovery in a state where the rotary seal member 33 is brought into contact with the end wall of the basket to close the opening on the inner peripheral side of the end wall of the basket. The rotation drive device 55 of the basket and the crystal scraping-off device so as to sequentially carry out a crystal collection step of sucking and collecting crystals dried by the suction tube while rotating the basket with the tip of the basket being at the final suction position. , A slurry supply device 20, a cleaning liquid supply device 24, and a heating device 22.
It is preferable to provide a control device for controlling the crystal recovery device 23 and the linear drive device 31 in a predetermined sequence. Such a control device can be configured by using a microcomputer.

In the above description, the center axis of the basket 12 is always inclined at a constant angle with respect to the horizontal direction. However, in the present invention, the center axis of the basket is set at least in the step of collecting crystals. The bottom wall 12b may be inclined obliquely downward at a certain angle with respect to the horizontal direction.
Does not need to be inclined at a fixed angle with respect to the horizontal direction. For example, the support mechanism of the basket and the casing is configured so that the inclination angle of the basket and the casing can be appropriately adjusted, and in the solid-liquid separation step, the washing step, the crystal scraping step and the drying step, the central axis of the basket is set. The horizontal direction may be maintained, and in the crystal recovery step, the central axis may be inclined at a predetermined angle with respect to the horizontal direction so that the bottom wall faces obliquely downward.

In the above example, a heating device using hot water as a heat source is used, but a heating device using an electric heater as a heat source may be used.

In the examples shown in FIGS. 1 to 4, the pressure inside the casing is reduced when drying the crystal. However, it is not always necessary to reduce the pressure inside the casing when drying the crystal.

In the above example, the fixed cover 14 is supported on the flange plate 9f via the connecting tube 15, but the upper end of the cylindrical member in which the fixed cover 14 and the connecting tube 15 are integrated is connected to the inner surface of the flange plate 9f. And the bottom plate portion of the cylindrical member may be used as the fixing lid 14.

As shown in the above example, the cover of the casing is formed in a cylindrical shape having a peripheral wall 9a surrounding the basket and an end wall 9c closing the axial end of the peripheral wall. If the entirety of the cylindrical cover is opened and closed, the entire basket can be exposed with the cover opened, so that the basket and its surroundings can be easily cleaned. However, the present invention is not limited to the case where such a casing is used, and the present invention is also applicable to a case where only a portion corresponding to the end wall 9c of the cover 9 can be opened and closed as a cover. Of course, the invention can be applied.

[0088]

As described above, according to the present invention, the rotary seal member for closing the opening on the inner peripheral side of the end wall of the basket while contacting the basket and rotating with the basket is provided. When the crystals are dried in the basket and when the crystals are collected, there is an advantage that the dried and fine crystals can be prevented from leaking out of the basket.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a centrifugal filtration device according to the present invention.

FIG. 2 is an enlarged sectional view showing a configuration of a main part of FIG. 1 in detail.

3 (A) to 3 (D) are operation explanatory views for explaining operations from a solid-liquid separation step to a washing step performed using the centrifugal filtration device shown in FIG. 1;

FIGS. 4A to 4D are operation explanatory diagrams for explaining operations from a crystal scraping step to a crystal recovery step performed using the centrifugal filtration device shown in FIG.

[Explanation of symbols]

 2 Base frame 9 Casing cover 10 Casing 12 Basket 12a Peripheral wall 12b Bottom wall 12c End wall 14 Fixed lid 20 Slurry supply device 21 Crystal scraping device 22 Heating device 23 Crystal recovery device 23A Crystal recovery tube 23b Swirling part 24 Cleaning liquid Supply device 31 Linear drive device 32 Seal support member 33 Rotary seal member 37 Rotary body

Claims (2)

(57) [Claims] 1. A cylindrical peripheral wall formed with a large number of transmission holes, a bottom wall closing one end of the peripheral wall in the axial direction, and a radially inner side from the inner periphery of the other axial end of the peripheral wall. The slurry is separated into a liquid component and crystals by centrifugal filtration of the slurry using a centrifugal filtration device including a basket having an annular end wall protruding into the container and a rotation drive device for rotating the basket. A solid-liquid separation step of forming crystals on the inner periphery of the basket, a crystal scraping step of scraping off crystals formed on the inner periphery of the basket, a drying step of drying the crystals in the basket, A crystal recovery step of suctioning and recovering crystals scraped off from the inner periphery of the basket by a crystal recovery suction tube inserted into the basket, wherein the crystal is brought into contact with an end wall of the basket from the outside. The A rotating seal member that rotates together with the basket while keeping the opening on the inner peripheral side of the inner wall closed so as to be retractable to a position where it does not contact the end wall; Then, the center axis of the basket is inclined at a certain angle with respect to the horizontal direction so that the bottom wall of the basket faces obliquely downward. In the solid-liquid separation step, the rotary seal member is retracted. When performing the crystal scraping step, the drying step, and the crystal recovery step, the rotating seal member is brought into contact with the end wall of the basket to close the opening on the inner peripheral side of the end wall of the basket. In the crystal recovery step, the tip of the crystal recovery suction tube enters the crystal while rotating the rotary seal member abutting on the end wall of the basket together with the basket. The suction tube, and finally displace the tip of the suction tube to a position close to the corner between the lowermost part of the peripheral wall of the inclined basket and the bottom wall of the basket. A centrifugal filtration method, wherein the crystals collected in the tube are sucked. 2. A casing having an openable and closable cover, a cylindrical peripheral wall formed with a large number of transmission holes, a bottom wall closing one axial end of the peripheral wall, and an axial direction of the peripheral wall. A basket rotatably supported in the casing having an annular end wall protruding inward in the radial direction from the inner periphery of the other end, a rotation driving device for rotating the basket, and the basket A slurry supply device for supplying slurry into the basket, a crystal scraping device for scraping crystals formed on the inner periphery of the peripheral wall of the basket, and a crystal collection suction tube for inserting crystals in the basket into the basket A crystal recovery device for suctioning and recovering by means of a crystal recovery device, wherein the inner peripheral surface of the end wall of the basket is supported by a cover of the casing when the cover is closed. A fixed lid concentrically disposed on the side with an annular gap therebetween; a linear drive device supported by the cover of the casing; and an end wall of the cover and the basket when the cover of the casing is closed. Between the forward position set by the linear drive device at a position near the end wall of the basket and the retracted position set at a position near the cover of the casing by the linear drive device. A seal support member that is linearly displaced along a central axis, and rotatably supported by the seal support member, wherein the seal support member is separated from an end wall of the basket when the seal support member is at the retracted position. An annular gap formed between the end wall of the basket and the fixed lid for holding and abutting on the end wall of the basket when the seal support member is in the advanced position. An annular rotating seal member that keeps the space closed, wherein the rotating seal member is provided so as to rotate with the basket in a state in which the rotating seal member is in contact with an end wall of the basket. At least when the crystal is recovered by the crystal recovery apparatus, the crystal is supported so that its central axis is inclined obliquely and the bottom wall portion faces obliquely downward. The basket has a revolving part, and the tip of the revolving part is in a state of being inclined, and finally comes into a state close to a corner between the lowermost part of the peripheral wall of the basket and the bottom wall of the basket. Centrifugal filtration provided so that it can be displaced between a suction position and a retracted position in which the tip portion is retracted inward from a position corresponding to the inner peripheral portion of the opening of the basket. apparatus