CN109070100B - Centrifugal separation device and centrifugal separation method - Google Patents

Abstract

A centrifugal separation device is provided with: a cylindrical basket (2) provided with a filter screen (2a) and rotating around an axis (O) in the basket body; and a squeezing plate (7) that is housed in the basket (2), is rotatable as a unit, and is provided so as to be relatively movable with respect to the basket (2) in the direction of the axis (O), wherein, when the squeezing plate (7) squeezes and discharges the cake filtered out of the treatment product supplied into the inner basket (2) by means of the filter screen (2a) toward the open end (2b) of the basket (2), the centrifugal separation device sets the relative movement speed of the squeezing plate (7) and the basket (2) in the direction of the axis (O) to be lower in the direction in which the distance (D) between the squeezing plate (7) and the open end (2b) of the basket (2) in the direction becomes larger than in the direction in which the distance (D) becomes smaller.

Description

Centrifugal separation device and centrifugal separation method

Technical Field

The present invention relates to a squeeze-type centrifugal separation device and a centrifugal separation method for filtering a processed object supplied into a basket rotating around an axis by a filter screen provided in a basket body of the basket, and discharging a cake filtered from the processed object from an opening end of the basket by a squeezing plate housed in the basket so as to be rotatable integrally and relatively movable in the axis direction with respect to the basket.

The present application claims priority based on 2016 in Japanese application laid-open at 5.7.2016, and the contents of which are hereby incorporated by reference.

Background

As such a squeeze centrifugal separator, for example, patent document 1 discloses a two-stage basket type centrifugal separator including: an outer basket rotating about an axis; and an inner basket coaxially disposed within the outer basket, and advancing and retreating in the axial direction with respect to the outer basket while rotating integrally with the outer basket. The two-stage basket-type centrifugal separation device supplies the processed object filtered by centrifugal separation between a squeezing plate supported on the outer basket and arranged in the inner basket so as to face the opening of the processed object supply pipe and a distributor in the form of a circular ring plate arranged to surround the opening of the processed object supply pipe with a space therebetween.

In such a centrifugal separator, the processed matter supplied from the opening of the supply pipe to between the pressing plate and the distributor is filtered to form a cake while being deposited on the inner peripheral surface of the filter screen provided in the basket portion of the inner basket by centrifugal force. Further, since the inner basket advances toward the open end side of the outer basket, the blocks are also piled up in the axial direction of the inner basket. Then, the processed block is pressed by the pressing plate and discharged to the inner peripheral surface of the outer basket as the inner basket retreats relative to the outer basket. In addition, the cake of the processed matter thus discharged onto the inner peripheral surface of the outer basket is further filtered by the filter mesh of the outer basket, and is discharged from the open end of the outer basket by being pressed by the advance of the inner basket.

Patent document 1: japanese patent laid-open No. 2014-091093

In such a centrifugal separator, the basket and the squeeze plate are moved relative to each other in the axial direction (in the centrifugal separator described in patent document 1, the inner basket is moved forward and backward with respect to the squeeze plate) and are generally driven by hydraulic pressure using a hydraulic piston. Therefore, the moving speed in the forward direction and the moving speed in the backward direction are generally equal to each other. The supply amount of the treatment material supplied from the supply pipe is also generally constant per unit time.

When the inner basket advances relative to the pressing plate, the processed object is supplied to the filter screen which is relatively easy to filter after the processed object accumulated on the inner peripheral surface of the filter screen of the inner basket is pressed out by the pressing plate. On the other hand, when the inner basket is retracted with respect to the pressing plate, the processed material is supplied so as to be additionally added to the cake of the processed material which is accumulated on the inner peripheral surface of the filter screen of the inner basket and is gradually pressed out by the pressing plate, and therefore, it is difficult to filter the processed material.

Therefore, in the case of supplying a treatment product which is particularly difficult to filter, if the centrifugal separator is not increased in size such as by increasing the capacity of the basket, the filtration of the treatment product may be insufficient or it may be difficult to form a uniform cake when the inner basket is retracted, and the supply amount of the treatment product must be limited.

Further, centrifugal separation apparatuses are also known as follows: that is, in contrast to the centrifugal separation device described in patent document 1, the position of the basket in the rotation axis direction is constant, and the pressing plate housed in the basket is movable by advancing and retreating in the axis direction with respect to the basket. In such a centrifugal separator, when the pressing plate is retracted, the processed material is supplied to a filter screen which is easy to filter after the processed material is extruded into a cake. In contrast, as the extrusion plate advances, the treatment substance is replenished onto the cake of treatment substance that is gradually extruded by the extrusion plate. Therefore, filtration or cake formation is insufficient.

Disclosure of Invention

The present invention has been made under such a background, and an object thereof is to provide a centrifugal separation apparatus and a centrifugal separation method which can promote efficient filtration of a treatment product without increasing the size of a basket, increase the throughput, and form a uniform cake without increasing the capacity of the basket.

A first aspect of the centrifugal separation apparatus of the present invention includes: a cylindrical basket which is provided with a filter screen and rotates around an axis is arranged on the basket body; and a pressing plate housed in the basket and configured to be rotatable integrally and to be relatively movable in an axial direction with respect to the basket, the centrifugal separation device pressing and discharging, by the pressing plate, the cake filtered out of the processed matter supplied into the basket by the filter screen toward an open end side of the basket, a relative movement speed of the pressing plate and the basket in the axial direction being set to be smaller in a direction in which an interval in the axial direction between the pressing plate and the open end of the basket becomes larger than in a direction in which the interval in the axial direction between the pressing plate and the open end of the basket becomes smaller.

In addition, a first aspect of the centrifugal separation method of the present invention is as follows: the centrifugal separation method is a method of supplying a processed material into a cylindrical basket which is provided with a filter screen on a basket body and rotates around an axis, and pressing and discharging a cake filtered from the processed material by the filter screen toward an opening end side of the basket by a pressing plate which is housed in the basket, is rotatable integrally, and is provided so as to be relatively movable in the axis direction with respect to the basket.

In the first aspect of the centrifugal separation device and the first aspect of the centrifugal separation method, for example, when the squeeze plate is located at a constant position in the axial direction and the basket is movable forward and backward in the axial direction as in the centrifugal separation device described in patent document 1, the direction in which the axial direction gap between the squeeze plate and the open end of the basket increases is the basket forward direction, and the direction in which the gap decreases is the basket backward direction. Conversely, when the basket is at a constant position in the axial direction and the squeezing plate can move forward and backward in the axial direction, the direction in which the axial distance between the squeezing plate and the open end of the basket increases is the direction in which the squeezing plate moves backward, and the direction in which the distance decreases is the direction in which the squeezing plate moves forward.

That is, in the first aspect of the centrifugal separation apparatus and the first aspect of the centrifugal separation method having the above-described configurations, when one of the basket and the squeezing plate moves relative to the other, the relative movement speed when the processed object is supplied to the filter screen in a relatively easy-to-filter state in which the processed object deposited on the inner peripheral surface of the filter screen of the basket is squeezed out by the squeezing plate is smaller than the relative movement speed when the processed object is supplied to the filter screen in a difficult-to-filter state in which the processed object remains.

Therefore, even if the supply amount of the processed object is increased under the condition that the basket capacity is the same, more processed objects can be supplied to the filtering screen of the basket in the easy filtering state. On the other hand, when the relative movement speeds at the time of forward movement and backward movement of the relative movement are set in this manner and the time of one forward and backward stroke is set to be the same, the relative movement speed when the treatment object is supplied to the filter mesh in the difficult-to-filter state is higher than the relative movement speed when the treatment object is supplied to the filter mesh in the easy-to-filter state. Therefore, the supply amount of the treatment material to be added to the cake of the treatment material remaining in the filter screen is reduced, and a uniform cake can be formed.

Therefore, according to the centrifugal separation apparatus and the centrifugal separation method configured as described above, even when the basket capacity is not increased to increase the size or one advance and retreat stroke time is not increased, more processed matter can be supplied to the filter mesh in the easy-to-filter state, and the supply amount of the processed matter supplied to the filter mesh in the difficult-to-filter state can be suppressed. Therefore, the treated matter can be efficiently filtered and the treatment amount can be increased, and the formation of uniform lumps can be promoted.

Further, in the case where the relative movement speed of the pressing plate with respect to the basket in the axial direction is set to be smaller in the direction in which the interval between the pressing plate and the open end of the basket in the axial direction becomes larger than in the direction in which the interval becomes smaller, if the ratio thereof is too large, it is difficult to set the relative movement speed of one member of the basket and the pressing plate with respect to the other member. Therefore, a large amount of the treatment substance may not be reliably supplied to the filter mesh in the easy-to-filter state.

Therefore, it is preferable that the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket increases be equal to or higher than 1/4 of the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket decreases. However, even if the ratio of the relative movement speeds is close to 1 and the speed difference is too small, the above-described operation may not be efficiently achieved. Therefore, it is preferable that the relative movement speed in the direction in which the interval increases be set to 2/3 or less of the relative movement speed in the direction in which the interval decreases.

Further, for example, when one member of the basket and the squeeze plate is moved forward and backward with respect to the other member by hydraulic driving using a conventional hydraulic piston, the setting of the relative movement speed of the forward and backward movement may be applied. In this case, the discharge speed of the hydraulic oil may be determined by determining the diameter of the hydraulic oil flow path between the forward and backward directions, by providing a speed controller, or by bypassing the cylinder discharge side flow path. In this case, the hydraulic pressure at the time of switching between forward and backward may be unstable, and thus it may be difficult to set the predetermined relative movement speed.

Therefore, when one of the basket and the squeeze plate is driven, for example, a so-called electric cylinder is used which converts rotation of a motor (servo motor) transmitted to a threaded shaft of a ball screw or the like into linear motion of a piston rod by screwing a nut coaxially attached to the piston rod to the threaded shaft. Further, a linear cylinder in which a piston rod is directly linearly moved by a linear motor may be used. Alternatively, it is preferable to use a highly compliant motor, such as a so-called fastener-type actuator, which engages two or more chains with each other, pulls the chains to advance in a telescopic column by means of the motor, and pulls the chains back and forth to linearly move the chains while releasing the engagement of the chains.

As described above, according to the present invention, even when the basket capacity is not increased to increase the size or the one advance/retreat stroke time is not increased, the processed object can be efficiently filtered to increase the processing amount, and uniform lumps can be formed. Therefore, the centrifugal separation apparatus can reduce the cost of the apparatus itself, the installation space of the apparatus, and the installation base by reducing the weight of the apparatus, and can stably and easily perform the post-treatment of the cake.

Drawings

Fig. 1 is a sectional view showing a schematic configuration of a centrifugal separator according to a first embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view showing the basket periphery in a state where the inner basket is retracted with respect to the pressing plate (a state where the axial interval between the pressing plate and the open end of the basket is reduced) in the embodiment shown in fig. 1.

Fig. 3 is an enlarged cross-sectional view showing the basket periphery in a state where the inner basket advances relative to the pressing plate (a state where the axial distance between the pressing plate and the open end of the basket is increased) in the embodiment shown in fig. 1.

Fig. 4 is an enlarged cross-sectional view showing the periphery of the basket in a state where the pressing plate advances relative to the basket (a state where the axial interval between the pressing plate and the open end of the basket is reduced) in the centrifugal separation device according to the second embodiment of the present invention.

Fig. 5 is an enlarged cross-sectional view showing the basket periphery in a state where the pressing plate is retracted with respect to the basket (a state where the axial interval between the pressing plate and the open end of the basket is increased) in the embodiment shown in fig. 4.

Detailed Description

Fig. 1 to 3 show a centrifugal separator according to a first embodiment of the present invention, and are examples of applying the present invention to a two-stage basket-type centrifugal separator including an outer basket and an inner basket as described in patent document 1. That is, the centrifugal separation device in the present embodiment includes: a cylindrical outer basket 1 having an outer filter mesh 1a mounted on a basket body and centered on a horizontal axis O; and a cylindrical inner basket 2 coaxially housed in the outer basket 1 and having an inner filter mesh 2a attached to a basket body. In the first embodiment, the inner basket 2 is a basket in the present invention, and a cylindrical wire screen or a plate screen is used as the outer filter screen 1a or the inner filter screen 2 a.

The cylindrical outer basket 1 and inner basket 2 are bottomed cylindrical shapes having circular open ends 1b, 2b provided at one end in the axis O direction (right end in the axis O direction in fig. 1 to 3) and the other end (left end in the axis O direction in fig. 1 to 3) attached to and held by disc- shaped holding plates 1c, 2 c. The length of the inner basket 2 in the direction of the axis O is shorter than the length of the outer basket 1 in the direction of the axis O. The inner basket 2 is housed inside the casing 3 and rotates integrally with the outer basket 1 about the axis O. The outer diameter of the open end 2b of the inner basket 2 is, for example, such a size that another annular pressing plate, not shown, is provided at the open end 2b and the pressing plate can be brought into sliding contact with the inner peripheral surface of the outer filter mesh 1a of the outer basket 1.

The holding plate 1c of the outer basket 1 is attached to one end of a hollow main shaft 5, and the main shaft 5 is rotatably supported by a bearing 4 and inserted into the housing 3 along the axis O. The outer basket 1 rotates about the axis O by transmitting a rotational force of a motor or the like to a pulley not shown to rotate the spindle 5. Further, a pressing shaft 6 is inserted into the main shaft 5 so as to be integrally rotatable and advance and retreat in the axis O direction via a key not shown. One end of the pressing shaft 6 is slidably inserted through the holding plate 1c of the outer basket 1 and is attached to the holding plate 2c of the inner basket 2, so that the inner basket 2 is also rotatable integrally with the outer basket 1 and can advance and retreat in the direction of the axis O at the other end side in the outer basket 1.

Further, a plurality of support shafts 1d are attached to the holding plate 1c of the outer basket 1 at positions distant from the axis O on the outer peripheral side so as to extend to the one end side at intervals in the circumferential direction and in parallel with the axis O. These support shafts 1d slidably penetrate the holding plate 2c and protrude into the inner basket 2. A disk-shaped pressing plate 7 having an outer diameter capable of sliding contact with the inner peripheral surface of the inner filter screen 2a is attached to one end of the support shaft 1 d. Therefore, the pressing plate 7 is rotatable integrally about the axis O coaxially with the outer basket 1 and the inner basket 2, and is relatively movable in the direction of the axis O with respect to the inner basket 2.

Further, a ring-plate-shaped dispersion plate (distributor) 8 having an opening at the center is integrally supported on the one end side of the pressing plate 7 at a distance from the pressing plate 7. A supply pipe 9 through which the treatment material is inserted is attached to the housing 3. The supply pipe 9 is inserted into the opening of the dispersion plate 8 through the opening ends 1b and 2b of the outer basket 1 and the inner basket 2, and the supply port of the supply pipe 9 opens between the squeeze plate 7 and the dispersion plate 8.

Further, a block receiving ring 3a having a substantially U-shape and opened to the inner peripheral side in a cross section along the axis O is disposed on the outer periphery of the open end 1b of the outer basket 1 so as to be supported by the housing 3 and surround the open end 1 b. A mass chute, not shown, is provided on the mass receiving ring 3a, and after the mass discharged from the open end 1b of the outer basket 1 is received by the mass receiving ring 3a, the mass is discharged from a discharge port 3b provided below the housing 3 via the mass chute.

On the other hand, the other end of the pressing shaft 6 protrudes beyond the other end of the main shaft 5, and a forward/backward driving unit 11 is connected to the protruding other end of the pressing shaft 6 via a bearing housing 10, and the forward/backward driving unit 11 allows the rotation of the pressing shaft 6 and moves forward/backward along the axis O direction together with the inner basket 2. The bearing housing 10 is configured to support the other end portion of the pressing shaft 6 rotatably by a bearing or the like, not shown, and to be attached so as to be able to advance and retreat integrally with the pressing shaft 6 in the axis O direction via the bearing without rotating relative to the pressing shaft 6 that rotates integrally with the main shaft 5.

The forward/backward driving unit 11 in the present embodiment is driven by a motor, and in particular, transmits the rotation of the motor (servo motor) 11a to a screw shaft such as a ball screw (not shown) extending in the direction of the axis O in the cylinder block 11 b. A nut coaxially attached to a piston rod, not shown, is screwed to the threaded shaft, and the forward/backward driving unit 11 converts the rotation of the motor 11a into linear motion of the piston rod via the threaded shaft and the nut. Such a forward/backward driving unit 11 is a so-called electric cylinder, a servo cylinder, or an electric actuator.

The relative movement speed of the inner basket 2 and the squeeze plate 7 in the axis O direction, which is generated along with the advance and retreat of the squeeze shaft 6 by the advance and retreat driving portion 11, is set as follows. That is, the relative movement speed in the direction in which the distance D in the axis O direction between the pressing plate 7 and the open end 2b of the inner basket 2 increases is set to be smaller than the relative movement speed in the direction in which the distance D in the axis O direction between the pressing plate 7 and the open end 2b of the inner basket 2 decreases. In addition, when the relative movement speed is set in this manner, it may be controlled so that the relative movement speed is appropriately adjusted during the operation of the centrifugal separation apparatus, and it may be set in advance so that such control is performed before the operation. Such control can be easily and automatically performed by inputting a program in advance to a control unit of a computer or the like including known components such as a CPU and a memory for controlling the motor 11 a.

Specifically, in the present embodiment, the pressing plate 7 is fixed to the main shaft 5 in the direction of the axis O by the support shaft 1d and the holding plate 1c of the outer basket 1, and the inner basket 2 is advanced and retreated in the direction of the axis O by the pressing shaft 6. Therefore, as shown in fig. 1 and 2, the inner basket 2 is moved forward from the state where the inner basket 2 is retracted to one end side in the axis O direction, whereby the open end 2b of the inner basket 2 is separated from the pressing plate 7 and the interval D is increased as shown in fig. 3. The relative speed of the outer basket 1 and the inner basket 2 in the direction in which the interval D becomes larger is set to be smaller than the moving speed in the direction in which the interval D becomes smaller, in which the inner basket 2 retreats from the state shown in fig. 3 to the other end side and the opening end 2b approaches the pressing plate 7 and the interval D becomes smaller.

In one embodiment of the centrifugal separation method of the present invention using the centrifugal separation apparatus thus constructed, the outer basket 1 and the inner basket 2 are rotated integrally, and a constant amount of a treatment product (slurry) in which solid-liquid substances are turbid is supplied from the supply pipe 9 per unit time. The supplied treatment product reaches the pressing plate 7, and the treatment product is dispersed from between the pressing plate 7 and the dispersion plate 8 to the outer peripheral side by a centrifugal force and adheres to the inner peripheral surface of the inner filter mesh 2a of the inner basket 2. While the treatment object is supplied in this way, the inner basket 2 is advanced from the state where the inner basket 2 is retracted as shown in fig. 1 and 2. Then, the processed matter is filtered by centrifugal force while being continuously accumulated in the direction of the axis O on the inner peripheral surface of the inner screen 2a of the advancing inner basket 2, thereby forming a cake (lump) of the processed matter.

Next, when the inner basket 2 that has advanced in this manner is shifted to the retracted position after reaching the end of the advancing stroke as shown in fig. 3, the lumps of the treatment substances deposited on the inner peripheral surface of the inner filter screen 2a are sequentially pushed toward one end of the inner basket 2 by the pushing plate 7 that has advanced relative to the retracted inner basket 2. The cake of the processed matter accumulated on the one end side is discharged from the open end 2b onto the inner peripheral surface of the outer filter screen 1a of the outer basket 1, and is continuously accumulated while still being further filtered by the centrifugal force in the axis O direction.

The lumps of the processed matter thus deposited on the inner peripheral surface of the outer filter mesh 1a and filtered pass through the next advance of the inner basket 2 reaching the end of the retreat stroke, and are sequentially pressed toward one end side by the open end 2b of the inner basket 2 or another pressing plate, not shown, provided at the open end 2 b. Then, the processed pieces accumulated on the one end side are discharged from the open end 1b of the outer basket 1 to the piece receiving ring 3a, and further discharged from the discharge port 3b of the housing 3 through the piece chute as described above.

When the cake is formed by filtering the processed product by centrifugation in this manner, the centrifugal separation apparatus and the centrifugal separation method set the relative movement speed of the inner basket 2 and the squeeze plate 7 in the axis O direction as follows. That is, the moving speed in the forward direction of the inner basket 2 in which the distance D in the axis O direction between the pressing plate 7 and the open end 2b of the inner basket 2 increases is set to be smaller than the moving speed in the backward direction of the inner basket 2 in which the distance D in the axis O direction between the pressing plate 7 and the open end 2b of the inner basket 2 decreases. That is, if the single advance/retreat stroke time of the conventional centrifugal separation apparatus and centrifugal separation method is the same as the single advance/retreat stroke time of the forward and retreat inner baskets, the moving speed of the inner basket 2 in the forward direction in the present embodiment is smaller than the conventional moving speed.

Therefore, when the inner basket 2 moves forward, the processed object supplied from the supply pipe 9 takes a longer time to be gradually accumulated on the inner circumferential surface of the inner filter screen 2a than when the inner basket 2 moves backward, and the accumulated processed object passing through the previous backward movement of the inner basket 2 and being pressed by the pressing plate 7 is less. Therefore, even if the capacity of the inner basket 2 is the same as the conventional capacity, a larger amount of the treatment substance can be supplied to the inner peripheral surface of the inner filter mesh 2a in a state where the accumulated treatment substance is small and the filtration is easy.

On the other hand, in the centrifugal separation apparatus and the centrifugal separation method having the above-described configuration, the moving speed of the inner basket 2 when the processed object accumulated on the inner circumferential surface of the inner filter screen 2a due to the retreat of the inner basket 2 is pushed out by the squeeze plate 7 becomes larger as compared with the conventional case where one stroke time is the same and the moving speeds of the advance and retreat are equal. Therefore, the amount of the treatment material that is further added to the treatment material deposited on the inner peripheral surface of the inner filter screen 2a on the one end side of the squeezing plate 7 in the axis O direction can be reduced. Therefore, the amount of the treatment material supplied to the inner filter screen 2a in which the treatment material is accumulated and which is in a difficult-to-filter state can be suppressed.

Therefore, according to the centrifugal separation apparatus and the centrifugal separation method thus configured, there is no need to increase the size of the centrifugal separation apparatus by increasing the capacity of the inner basket 2 (basket), or to lengthen one advance/retreat stroke time of the movement of the inner basket 2 with respect to the pressing plate 7. By increasing the supply amount of the treatment object to the inner filter screen 2a in the easy-to-filter state, more treatment objects can be reliably and efficiently processed in one stroke. Further, by suppressing the treatment material supplied to the inner filter mesh 2a in a difficult-to-filter state, a uniform cake can be formed over the entire length of the inner basket 2. Therefore, the centrifugal separation device can be reduced in installation cost and installation space, and the installation base can be simplified by reducing the weight of the device, and the post-treatment of the filtered cake can be stably and easily performed.

In the present embodiment, when the moving speed of the inner basket 2 with respect to the squeeze plate 7 is set in this manner, the electric motor 11a is used as the advancing/retreating driving unit 11 for advancing/retreating the inner basket 2 by the squeeze shaft 6. However, even when the squeeze shaft 6 and the inner basket 2 are moved forward and backward by hydraulic driving as in the conventional art, the moving speed may be set by dividing the flow path diameter of the hydraulic oil between forward and backward movement, by providing a speed controller, or by dividing the discharge speed of the hydraulic oil by bypassing the cylinder discharge side flow path. However, in this case, there is a possibility that the hydraulic pressure becomes unstable when switching between the forward and backward operations, which is peculiar to the hydraulic drive, and it is difficult to reliably set the predetermined relative movement speed.

In contrast, the forward/backward driving unit 11 using the motor 11a as in the present embodiment has high compliance, and can rapidly change the moving direction even when switching forward/backward. Further, the moving speed can be reliably and stably set, and the centrifugal separation apparatus and the centrifugal separation method are particularly suitable for cases where the relative moving speed of the inner basket 2 with respect to the squeeze plate 7 is different in magnitude as in the centrifugal separation apparatus and the centrifugal separation method configured as described above.

In addition, as the forward/backward driving unit 11 using the motor 11a, an electric cylinder that converts the rotation of the motor 11a into the linear motion of the piston rod by a screw shaft and a nut as in the above-described embodiment may be used. In addition, a linear cylinder in which a piston rod is directly linearly moved by a linear motor may be used. Further, a so-called fastener type actuator or the like may be used, which engages two or more chains with each other, pulls the chains forward in a columnar shape by a motor, and pulls the chains back and moves them backward to linearly move the chains while releasing the engagement of the chains.

Next, fig. 4 and 5 show a centrifugal separator according to a second embodiment of the present invention. The same reference numerals are assigned to the same portions as those of the centrifugal separation device of the first embodiment, and the description thereof is omitted.

In the centrifugal separation device according to the second embodiment shown in fig. 4 and 5, the other end portion in the axis O direction, which is not shown, is the same as that of the centrifugal separation device according to the first embodiment, and therefore, illustration thereof is omitted.

In the first embodiment, the inner basket 2 is housed in the outer basket 1 so as to be rotatable integrally, the inner basket 2 is attached to the pressing shaft 6 so as to advance and retreat in the direction of the axis O, and the outer basket 1 and the pressing plate 7 supported by the outer basket 1 are held at a constant position in the direction of the axis O, whereby the pressing plate 7 is movable relative to the basket (the inner basket 2) in the direction of the axis O. In the second embodiment, a single basket 21 provided with a filter mesh 21a on a basket body portion and having an open end 21b at one end in the axis O direction is attached to one end of the main shaft 5 by a holding plate 21 c. The basket 21 is held at a constant position in the axis O direction, a pressing plate 22 having an outer diameter capable of sliding contact with the inner peripheral surface of the filter mesh 21a is coaxially attached to one end of the pressing shaft 6 inserted into the holding plate 21c, and the pressing plate 22 is advanced and retreated in the axis O direction. Thereby, the pressing plate 22 is relatively movable in the axis O direction with respect to the basket 21.

Therefore, in the second embodiment, the basket 21 and the open end 21b of the basket are located at a constant position in the axis O direction, and the pressing plate 22 can move forward and backward in the axis O direction. Therefore, the direction in which the distance D between the pressing plate 22 and the opening end 21b of the basket 21 in the direction of the axis O increases is the direction in which the pressing plate 22 moves backward, and the direction in which the distance decreases is the direction in which the pressing plate 22 moves forward.

In the present embodiment, the relative movement speed of the pressing plate 22 and the basket 21 in the axis O direction is also set as follows. That is, the relative movement speed in the direction in which the axial distance D between the squeezing plate 22 and the open end 21b of the basket 21 is increased, that is, in the direction in which the squeezing plate 22 is retreated, which is the direction in which the axial distance D between the squeezing plate 22 and the open end 21b of the basket 21 is increased, from the state in which the squeezing plate 22 advances with respect to the basket 21 shown in fig. 4, is set to be smaller than the relative movement speed in the direction in which the axial distance D between the squeezing plate 22 and the open end 21 is increased, that is, the direction in which the axial distance D between the squeezing plate 22 and the open end 21 is decreased, that is, shown in fig. 5.

Therefore, in the present embodiment, when the pressing plate 22 is moved backward after pressing the treatment object deposited on the inner peripheral surface of the filter mesh 21a, it takes a long time to slowly supply a new treatment object from the supply pipe 9, and a large amount of treatment object is deposited on the inner peripheral surface of the filter mesh 21a in a state where the treatment object is pressed, and the deposition is small and the filtration is easy. Therefore, a large amount of the treatment object can be efficiently filtered. On the other hand, when the pressing plate 22 advances to push out the accumulated processing object, the moving speed is high when the distance between the pressing plate 22 and the opening end 21b is small, and the processing object to be added to the already accumulated processing object can be reduced. Therefore, a uniform lump can be formed over the entire length of the basket 21.

In addition, as in the first and second embodiments, when the relative movement speed of the squeeze plates 7 and 22 in the direction of the axis O of the baskets 2 and 21 is set to be lower in the direction in which the distance D in the direction of the axis O becomes larger than in the direction in which the distance D becomes smaller, if the ratio is too large, it is difficult to set the movement speed of the basket (inner basket 2) or the squeeze plate 22 that is moving. Therefore, a large amount of the treatment substance may not be reliably supplied to the filter screens 2a and 21a in the easy-to-filter state, or a large amount of the treatment substance may be added to the filter screens 2a and 21a in the difficult-to-filter state.

Therefore, it is preferable that the relative movement speed in the direction in which the distance between the squeezing plates 7 and 22 and the open ends 2b and 21b of the baskets 2 and 21 in the direction of the axis O is increased be set to be smaller than or equal to 1/4 of the relative movement speed in the direction in which the distance D is decreased. However, even if the relative movement speed difference is small, the above-described operation may not be efficiently achieved. Therefore, it is more preferable to set the relative movement speed in the direction in which the interval D increases to 2/3 or less of the relative movement speed in the direction in which the interval D decreases. The present invention is applied to a centrifugal separation apparatus and a centrifugal separation method including a two-stage basket, i.e., the outer basket 1 and the inner basket 2, in the first embodiment and including a single basket 21 in the second embodiment. However, it is needless to say that the present invention can be applied to a centrifugal separation device and a centrifugal separation method having three or more stages of baskets.

Industrial applicability

According to the centrifugal separation apparatus and the centrifugal separation method of the present invention, even when the basket capacity is not increased to increase the size or the one advance/retreat stroke time is not increased, the processed matter can be efficiently filtered, the processing amount can be increased, and uniform lumps can be formed. Therefore, the centrifugal separation apparatus can reduce the cost of the apparatus itself, the installation space of the apparatus, and the installation base by reducing the weight of the apparatus, and can stably and easily perform the post-treatment of the cake.

Description of the reference numerals

1 outer basket

1a external filtering screen

1b open end of outer basket 1

2 inner basket (basket)

2a internal filtering screen

2b open end of inner basket 2

3 case

5 Main shaft

6 extrusion shaft

7. 22 extrusion plate

8 dispersion board

9 supply pipe for processed material

10 bearing box

11 advancing and retreating driving part

11a motor

11b cylinder box

21 basket

21a filter screen

21b open end of basket 21

Axis of rotation of O-basket 21 (outer basket 1, inner basket 2)

Distance in the axis O direction between the D- press plates 7 and 22 and the open ends 2b and 21b of the inner basket 2 and the basket 21

Claims (6)

1. A centrifugal separation device is provided with: a cylindrical basket which is provided with a filter screen and rotates around an axis is arranged on the basket body; and a pressing plate housed in the basket, integrally rotatable, and provided to be relatively movable in the axial direction with respect to the basket, the centrifugal separation device pressing and discharging, by the pressing plate, the cake filtered out of the processed matter supplied into the basket by the filter screen toward an open end side of the basket,

a relative movement speed of the squeeze plate and the basket in the axial direction is set to be lower than a relative movement speed in a direction in which an interval between the squeeze plate and an open end of the basket in the axial direction becomes larger than a relative movement speed in a direction in which an interval between the squeeze plate and an open end of the basket in the axial direction becomes smaller, wherein the processed object is supplied to the filter screen in an easy-to-filter state after the processed object deposited on the inner peripheral surface of the filter screen of the basket is extruded by the squeeze plate in the direction in which the interval between the squeeze plate and the open end of the basket in the axial direction becomes larger; and a step of feeding the processed object to the filter screen in a difficult-to-filter state in which the processed object remains in a direction in which the distance in the axial direction between the squeezing plate and the open end of the basket decreases.

2. The centrifugal separation device according to claim 1,

the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket increases is set to be equal to or greater than 1/4 of the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket decreases.

3. The centrifugal separation device according to claim 1 or 2,

the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket increases is set to be 2/3 or less of the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket decreases.

4. A centrifugal separation method for supplying a processed material into a cylindrical basket which is provided with a filter mesh at a basket body portion and rotates around an axis, and for pressing and discharging a cake filtered from the processed material by the filter mesh toward an opening end side of the basket by a pressing plate which is housed in the basket, is rotatable integrally, and is provided so as to be relatively movable in the axis direction with respect to the basket,

the centrifugal separation method sets a relative movement speed of the squeeze plate and the basket in the axial direction to be lower than a relative movement speed in a direction in which an interval between the squeeze plate and an open end of the basket in the axial direction becomes larger than a relative movement speed in a direction in which an interval between the squeeze plate and an open end of the basket in the axial direction becomes smaller, wherein the processed matter is supplied to the filter screen in an easy-to-filter state after the processed matter accumulated on an inner peripheral surface of the filter screen of the basket is squeezed out by the squeeze plate in the direction in which the interval between the squeeze plate and the open end of the basket in the axial direction becomes larger; and a step of feeding the processed object to the filter screen in a difficult-to-filter state in which the processed object remains in a direction in which the distance in the axial direction between the squeezing plate and the open end of the basket decreases.

5. The centrifugal separation method according to claim 4,

the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket increases is set to be greater than or equal to 1/4, which is the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket decreases.

6. The centrifugal separation method according to claim 4 or 5,

the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket increases is set to be 2/3 or less of the relative movement speed in the direction in which the axial distance between the squeezing plate and the open end of the basket decreases.

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