JP2018001116A - Centrifugal separator and centrifugal separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separator and a centrifugal separation method capable of increasing treatment capacity and forming a uniform cake by accelerating the efficient filtration of a material to be treated without large-sizing basket capacity.SOLUTION: In a centrifugal separator having a cylindrical basket 2 being disposed with a filtration screen 2a at a trunk and rotating around an axis line O and a pushing plate 7 housed in the basket 2, integrally rotatable and disposed so as to be relatively movable to the basket 2 in an axis line O direction, relative moving speed between the pushing plate 7 and the basket 2 in the axis line O direction is set so that the relative moving speed in a direction that a distance D between the pushing plate 7 and the opening end 2b of the basket 2 in the axis line O direction becomes large becomes smaller than the relative moving speed in a direction that the distance D becomes small when pushing and discharging a cake filtered by the filtration screen 2a from a material to be treated supplied into the basket 2 to the opening end 2b side of the basket 2 by the pushing plate 7.SELECTED DRAWING: Figure 1

Description

  In the present invention, the processed material supplied in the basket rotated about the axis is filtered by the filter screen provided in the barrel of the basket, and the cake filtered from the processed material is accommodated in the basket. The present invention relates to an extrusion-type centrifugal separation device and a centrifugal separation method for discharging from an opening end of a basket by an extrusion plate that can be rotated integrally and moved relative to the basket in the axial direction.

  As such an extrusion-type centrifuge, for example, Patent Document 1 discloses an outer basket that is rotated around an axis, and is coaxially disposed in the outer basket and rotated integrally with the outer basket. In a two-stage basket type centrifuge having an inner basket that is advanced and retracted in a direction, an inner basket is supported by an outer basket so as to face a processed product to be filtered by the outer basket. It is made to supply between the extrusion plate arrange | positioned in the inside, and the annular plate-shaped distributor arrange | positioned so that the opening part of the said supply pipe may be surrounded at intervals between this extrusion plate. Things are listed.

  In such a centrifugal separator, the processed material supplied between the extrusion plate and the distributor from the opening of the supply pipe is deposited on the inner peripheral surface of the filtration screen provided on the barrel of the inner basket by centrifugal force. While being filtered to form a cake, it also accumulates in the axial direction of the inner basket by the advance of the inner basket toward the open end side of the outer basket, and then is pushed out by the extrusion plate by the retreat of the inner basket with respect to the outer basket. It is discharged to the inner peripheral surface of the basket. Further, the cake of the processed product discharged to the inner peripheral surface of the outer basket in this way is further filtered by the filtration screen of the outer basket, pushed out by the advance of the inner basket, and discharged from the opening end.

JP, 2014-091093, A

  By the way, relative movement in the axial direction of the basket and the extrusion plate in such a centrifugal separator (in the centrifugal separator described in Patent Document 1, the advance and retreat of the inner basket with respect to the extrusion plate) is generally a hydraulic piston. The moving speed at the time of forward movement and the moving speed at the time of backward movement are usually equal speeds. Further, the supply amount of the processed material from the supply pipe is usually a constant amount per unit time.

  However, when the inner basket moves forward with respect to the extruded plate, the processed material deposited on the inner peripheral surface of the filtration screen of the inner basket is pushed out by the extruded plate, and the processed material is placed on the filter screen that is relatively easy to be filtered. In contrast, when the inner basket moves backward with respect to the extruded plate, the processed product is put on the cake of the processed product which is accumulated on the inner peripheral surface of the filtration screen of the inner basket and is being pushed out by the extruded plate. Therefore, the processed product is difficult to be filtered.

  For this reason, especially when a processed material that is difficult to filter is supplied, if the centrifugal separator is not enlarged, such as increasing the capacity of the basket, the processed material may not be sufficiently filtered when the inner basket is retracted, The formation of a simple cake may become difficult, and there may be a situation in which the supply amount of the processed product has to be limited.

  Contrary to the centrifugal separator described in Patent Document 1, the basket has a fixed position in the axial direction of rotation, and the extruded plate accommodated in the basket is in the axial direction with respect to the basket. Some are known to be movable by advancing and retreating. In such a centrifugal separator, contrary to the above, when the extruded plate moves backward, the processed product is supplied to a filter screen which is easy to be filtered after the cake of processed product is extruded, whereas the extruded plate Since the processed product supplied to the cake of the processed product being pushed out by the extruding plate is added, the filtration and the formation of the cake are also insufficient.

  The present invention has been made under such a background, and promotes efficient filtration of the processed material without increasing the basket capacity or the like, thereby increasing the processing amount and forming a uniform cake. It is an object of the present invention to provide a centrifuge device and a centrifuge method capable of achieving the above.

  In order to solve the above-described problems and achieve such an object, a centrifugal separator of the present invention includes a cylindrical basket provided with a filtration screen in a body portion and rotated around an axis, A cake which is accommodated and integrally rotatable and is provided so as to be movable relative to the basket in the axial direction, and is filtered from the processed product supplied into the basket by the filtration screen A centrifugal separator that extrudes the product to the opening end side of the basket by the extrusion plate and discharges it, and the relative movement speed in the axial direction of the extrusion plate, the basket, and the opening end of the basket is The relative movement speed in the direction in which the axial distance increases increases in the direction in which the axial distance between the extruded plate and the open end of the basket decreases. Characterized in that it is set to be smaller than the relative movement speed.

  Further, the centrifugal separation method of the present invention supplies a processed product into a cylindrical basket provided with a filtration screen in the body and rotated around an axis, and a cake filtered from the processed product by the filtration screen is supplied. A centrifugal separation method of pushing out and discharging to the opening end side of the basket by an extrusion plate housed in the basket and rotatable integrally with the basket and movable relative to the basket in the axial direction. The relative movement speed in the axial direction between the extrusion plate and the basket is set as the relative movement speed in the direction in which the interval between the extrusion plate and the opening end of the basket is increased in the axial direction. And the opening end of the basket are set so as to be smaller than the relative moving speed in the direction in which the axial distance is reduced.

  In such a centrifuge and a centrifuge method, for example, as in the centrifuge described in Patent Document 1, the extrusion plate is at a constant position in the axial direction, and the basket is movable forward and backward in the axial direction. In this case, the direction in which the axial distance between the extrusion plate and the open end of the basket increases is the direction when the basket moves forward, and the direction in which the interval decreases becomes the direction when the basket moves backward. On the other hand, when the basket is at a fixed position in the axial direction and the extruded plate is movable back and forth in the axial direction, the axial distance between the extruded plate and the open end of the basket is increased. The direction becomes the direction when the extruded plate moves backward, and the direction in which the interval decreases becomes the direction when the extruded plate moves forward.

  That is, in the centrifuge and the centrifuge method configured as described above, when one of the basket and the extrusion plate moves relative to the other, the processed material deposited on the inner peripheral surface of the filtration screen of the basket is removed from the extrusion plate. The relative movement speed when the processed material is supplied to the filter screen that is relatively easy to be filtered after being extruded by the filter is the same as that when the processed material is supplied to the filter screen that is difficult to filter while the processed material remains. It becomes smaller than the relative speed.

  For this reason, even if the supply amount of the processed material is increased when the capacity of the basket is the same, a larger amount of processed material can be supplied to the filtration screen of the basket that is easily filtered. On the other hand, when the movement speeds of the relative movement forward and backward are the same and the time of one stroke of advance and retreat is the same, the processed material is supplied to the filtration screen that is difficult to be filtered. Since the relative speed at the time of processing increases, the supply amount of the processed material added to the cake of the processed material remaining on the filtration screen decreases, and a uniform cake can be formed.

  Therefore, according to the centrifuge and the centrifuge method having the above-described configuration, it is possible to filter more processed materials without enlarging the capacity of the basket and increasing the time for one stroke of advancement / retraction. While being supplied to the filter screen in a state where it is easy to be filtered, the supply amount of the processed material supplied to the filter screen in a state where filtering is difficult can be suppressed. For this reason, it is possible to increase the throughput by efficiently filtering the processed product, and to promote the formation of a uniform cake.

  In this way, the relative movement speed in the axial direction of the extruded plate with respect to the basket is set so that the relative movement speed in the direction in which the axial distance between the extruded plate and the open end of the basket increases becomes smaller. When the ratio is set to be smaller than the relative movement speed, the relative movement speed with respect to the other of the basket and the extrusion plate is difficult to set, and the filtration screen is easily filtered. There is a risk that a large amount of processed material cannot be supplied reliably.

  For this reason, the relative movement speed in the direction in which the axial distance between the extruded plate and the open end of the basket increases is such that the axial distance between the extruded plate and the open end of the basket decreases. It is desirable that the relative movement speed is set to be small at a speed of 1/4 or more. However, even if the ratio of these relative movement speeds is close to 1 and the speed difference is too small, there is a possibility that the above-mentioned action cannot be effectively achieved. Therefore, the relative movement speed in the direction in which this interval increases. Is more preferably set to 2/3 or less of the relative movement speed in the direction of decreasing.

  In order to set the relative movement speed of advance and retreat in this way, for example, even when one of the basket and the pushing plate is moved forward and backward with respect to the other by hydraulic drive by a conventional hydraulic piston, the forward and backward relative movement speeds are set. This can be done by making a difference in the hydraulic oil flow path diameter, installing a speed controller, or providing a difference in the hydraulic oil discharge speed by bypassing the cylinder discharge side flow path. In the case of switching between advance and retreat, the hydraulic pressure becomes unstable, and it may be difficult to set a predetermined relative movement speed.

  Therefore, in such a case, as one of the driving means for the basket and the extrusion plate, for example, a rotation of an electric motor (servo motor) transmitted to a screw shaft such as a ball screw, and a nut attached coaxially to the piston rod are used. A so-called electric cylinder that is converted into a linear motion of the piston rod by being screwed to the screw shaft, a linear cylinder that linearly moves the piston rod directly by an electric linear motor, or an electric motor that engages two or more chains with each other. It is desirable to use a driving means by a highly responsive electric motor, such as a fastener-type actuator, which is moved forward in a columnar shape and moved linearly by being pulled back and retracted and retracted.

  As described above, according to the present invention, the processing volume can be efficiently filtered without increasing the basket capacity to increase the size of the basket or increasing the time for one stroke of advancement / retraction. While aiming at an increase, a uniform cake can be formed. Accordingly, along with this, it is possible to reduce the cost of the centrifuge device itself, reduce the installation space of the device, simplify the foundation of the installation by reducing the weight of the device, and stably and easily post-treat the cake. Can be performed.

It is sectional drawing which shows the outline of 1st Embodiment of the centrifuge of this invention. In the embodiment shown in FIG. 1, it is an expanded sectional view of the basket periphery showing a state in which the inner basket is retracted with respect to the push plate (a state in which the axial distance between the push plate and the open end of the basket is small). In the embodiment shown in FIG. 1, it is an expanded sectional view of the basket periphery showing a state in which the inner basket has advanced with respect to the push plate (a state in which the distance between the push plate and the open end of the basket in the axial direction is large). In 2nd Embodiment of the centrifuge of this invention, the expanded cross section around a basket which shows the state (state in which the space | interval of the axial direction of an extrusion plate and the opening end of a basket is small) which the extrusion plate advanced with respect to the basket FIG. FIG. 5 is an enlarged cross-sectional view of the periphery of the basket showing a state in which the extruded plate is retracted with respect to the basket in the embodiment shown in FIG. 4 (a state in which the axial distance between the extruded plate and the open end of the basket is large).

  1 to 3 show a first embodiment of a centrifuge of the present invention. The present invention is divided into two stages including an outer basket and an inner basket as described in Patent Document 1. FIG. This is applied to a basket-type centrifuge. That is, the centrifugal separator in the present embodiment is accommodated coaxially in a cylindrical outer basket 1 centering on a horizontal axis O having an outer filtration screen 1a attached to the body, and the outer basket 1. A cylindrical inner basket 2 having an inner filtration screen 2a attached to the body is also provided. In the first embodiment, the inner basket 2 is the basket in the present invention. As the outer filtration screen 1a and the inner filtration screen 2a, for example, a cylindrical wire screen or a plate screen is used.

  These cylindrical outer basket 1 and inner basket 2 have circular open ends 1b and 2b at one end (front end; right end in FIGS. 1 to 3) in the direction of the axis O, and the other end (rear end; FIG. 1 to FIG. 1). The left end in FIG. 3 is a bottomed cylindrical shape attached to and held by disc-shaped holding plates 1c and 2c, and the inner basket 2 has a shorter length in the direction of the axis O than the outer basket 1. It is accommodated in the casing 3 and is rotated integrally around the axis O. The outer diameter of the opening end 2b of the inner basket 2 is slid onto the inner peripheral surface of the outer filtration screen 1a of the outer basket 1 by providing, for example, another annular extruded plate (not shown) at the opening end 2b. It is said that it can be touched.

  The holding plate 1c of the outer basket 1 is rotatably supported by a bearing 4 and is attached to one end of a hollow main shaft 5 inserted into the casing 3 along the axis O, and is rotated by a motor or the like on a pulley (not shown). As the force is transmitted and the main shaft 5 rotates, the outer basket 1 rotates around the axis O. An extrusion shaft 6 is inserted into the main shaft 5 through a key so as to be integrally rotatable and capable of moving back and forth in the direction of the axis O. One end of the extrusion shaft 6 holds the holding plate 1c of the outer basket 1. By slidably passing through and attached to the holding plate 2c of the inner basket 2, the inner basket 2 can also rotate integrally with the outer basket 1 and can advance and retreat in the direction of the axis O on the other end side in the outer basket 1. It is said.

  Further, a plurality of support shafts 1d are provided on the holding plate 1c of the outer basket 1 so as to extend to the one end side in parallel to the axis O at a position spaced apart from the axis O toward the outer periphery in the circumferential direction. It is attached. These support shafts 1d slidably pass through the holding plate 2c and protrude into the inner basket 2, and one end of these support shafts 1d is slidably contacted with the inner peripheral surface of the inner filtration screen 2a. A disk-shaped extruded plate 7 having a diameter is attached. Therefore, the extrusion plate 7 can rotate integrally around the axis O coaxially with the outer basket 1 and the inner basket 2 and can move relative to the inner basket 2 in the direction of the axis O.

  In addition, an annular plate-like dispersion plate (distributor) 8 having an opening at the center is integrally supported at one end side of the extrusion plate 7 with a space from the extrusion plate 7. Further, a treated product supply pipe 9 is attached to and inserted into the casing 3, and this supply pipe 9 passes through the opening ends 1 b and 2 b of the outer basket 1 and the inner basket 2 and into the opening of the dispersion plate 8. The supply port is opened between the extrusion plate 7 and the dispersion plate 8.

  Further, on the outer periphery of the opening end 1 b of the outer basket 1, a “U” -shaped or U-shaped cake receiving ring 3 a whose section along the axis O opens to the inner peripheral side is supported by the casing 3 and opened. It arrange | positions so that the edge 1b may be surrounded. The cake receiving ring 3a is provided with a cake chute (not shown). After the cake discharged from the open end of the outer basket 1 is received by the cake receiving ring 3a, the cake receiving ring 3a receives the cake chute 3a through the chute. It is discharged from a discharge port 3b provided below.

  On the other hand, the other end of the extrusion shaft 6 protrudes from the other end of the main shaft 5, while allowing the rotation of the extrusion shaft 6 to the other end portion of the protruding extrusion shaft 6 via the bearing box 10, Advancing / retracting driving means 11 for moving the pushing shaft 6 in the direction of the axis O together with the inner basket 2 is connected. The bearing box 10 is configured so as not to rotate with respect to the extrusion shaft 6 that rotates integrally with the main shaft 5 while rotatably supporting the other end portion of the extrusion shaft 6 by a bearing or the like (not shown). It is attached to the extrusion shaft 6 so as to be able to advance and retract.

  Further, the forward / backward drive means 11 in the present embodiment is a drive means by an electric motor, and in particular, a ball screw (not shown) arranged so that the rotation of the electric motor (servo motor) 11a extends in the axis O direction in the cylinder box 11b. A nut that is coaxially attached to a piston rod (not shown) is screwed to the screw shaft, and the rotation of the electric motor 11a is transmitted to the screw rod through the screw shaft and the nut. This is a so-called electric cylinder, servo cylinder, or electric actuator that converts to linear motion.

  The relative movement speed of the inner basket 2 and the pushing plate 7 in the direction of the axis O with the advance and retreat of the pushing shaft 6 by the advance / retreat driving means 11 is the direction of the axis O between the pushing plate 7 and the opening end 2b of the inner basket 2. The relative movement speed in the direction in which the distance D increases is smaller than the relative movement speed in the direction in which the distance D in the axis O direction between the extrusion plate 7 and the opening end 2b of the inner basket 2 decreases. Is set to be In order to set the relative movement speed in this way, control may be performed so that the relative movement speed is appropriately adjusted during operation of the centrifugal separator, and such control is performed before operation. May be set in advance. Such control can be easily performed automatically by inputting a program in advance to a control means such as a computer for controlling the electric motor 11a.

  Specifically, in the present embodiment, the extrusion plate 7 is attached to the main shaft 5 via the support shaft 1d and the holding plate 1c of the outer basket 1 and fixed in the direction of the axis O, while the inner basket 2 is Since the inner basket 2 is moved back and forth in the direction of the axis O through the extrusion shaft 6, the inner basket 2 is moved forward to one end side in the direction of the axis O as shown in FIGS. As shown in FIG. 3, the relative movement speed in the direction in which the opening D 2b of the inner basket 2 is separated from the extrusion plate 7 and the interval D is increased is reversed from the state shown in FIG. By retreating toward the end side, the opening end 2b is brought into a state of approaching the extrusion plate 7, and is set so as to be smaller than the moving speed in the direction in which the distance D is increased.

  In one embodiment of the centrifugal separation method of the present invention using the centrifugal separator configured as described above, the processed product in which the solid liquid is turbid from the supply pipe 9 while rotating the outer basket 1 and the inner basket 2 together. (Slurry) is supplied in a constant amount per unit time. The supplied processed product hits the extrusion plate 7 and is dispersed from the space between the dispersion plate 8 and the outer peripheral side by centrifugal force, and adheres to the inner peripheral surface of the inner filtration screen 2 a of the inner basket 2. Therefore, when the inner basket 2 is advanced from the retracted state as shown in FIGS. 1 and 2 while supplying the processed material in this way, the processed material is placed on the inner peripheral surface of the inner filtration screen 2a of the inner basket 2 moving forward. While being continuously deposited in the direction of the axis O, it is filtered by centrifugal force to form a cake of processed material.

  Next, when the inner basket 2 thus advanced reaches the forward stroke end and turns backward as shown in FIG. 3, the cake of the processed material deposited on the inner peripheral surface of the inner filtration screen 2a is retracted. The extrusion plate 7 that moves forward relative to the basket 2 sequentially pushes one end side of the inner basket 2 and deposits on the one end side from the opening end 2b to the inside of the outer filtration screen 1a of the outer basket 1. It is discharged to the peripheral surface and is further filtered by centrifugal force while being continuously deposited in the direction of the axis O.

  Next, the cake thus deposited and filtered on the inner peripheral surface of the outer filtration screen 1a is moved to the open end 2b of the inner basket 2 or the open end by the next advance of the inner basket 2 reaching the retreat stroke end. The other extrusion plate provided in 2b is sequentially pushed out to one end side, and is also discharged from the one end accumulated from the opening end 1b of the outer basket 1 to the cake receiving ring 3a. Through the outlet 3b of the casing 3.

  Then, when the cake is formed by filtering the processed material in this way, the relative movement of the inner basket 2 and the extrusion plate 7 in the direction of the axis O is performed in the centrifugal separator and the centrifugal separation method having the above-described configuration. The opening plate 2 and the opening end 2b of the inner basket 2 are faster than the moving speed in the backward direction of the inner basket 2 where the distance D in the axis O direction between the pushing plate 7 and the opening end 2b of the inner basket 2 becomes smaller. Is set so that the moving speed of the inner basket 2 in the forward direction becomes small. That is, as compared with the conventional centrifugal separator and the centrifugal method in which the moving speed of the inner basket in the forward and backward directions is the same, the moving speed in the forward direction of the inner basket 2 becomes smaller if the time of one stroke of the forward and backward movement is the same.

  Accordingly, the processed product supplied from the supply pipe 9 is not removed from the inner filtration screen 2a after the processed product is pushed out by the push-out plate 7 by the backward movement of the inner basket 2 and the processed product remaining in the state is small. A large amount of processed material is deposited on the inner peripheral surface more slowly over time than when the inner basket 2 moves backward. For this reason, even if the capacity | capacitance of the inner basket 2 is the same as the past, more processed products can be supplied and filtered to the inner peripheral surface of the inner filtration screen 2a in a state where the accumulated processed products are small and easily filtered.

  On the other hand, in the centrifuge device and the centrifuge method having the above-described configuration, the inner basket 2 is moved backward so that the inner filtration screen 2a can move within the inner filtration screen 2a as compared with the conventional case where the time of one stroke is the same and the moving speed of advance and retreat is equal. The moving speed of the inner basket 2 when the processed material accumulated on the peripheral surface is pushed out by the extrusion plate 7 is increased. For this reason, since the amount of the processed product that is further deposited on the processed product as deposited on the inner peripheral surface of the inner filtration screen 2a on the one end side of the extruded plate 7 in the direction of the axis O can be reduced, In this way, it is possible to suppress the supply amount of the processed material to the inner filtration screen 2a in which the processed material is deposited and hardly filtered.

  Therefore, according to the centrifuge and the centrifuge method thus configured, the capacity of the inner basket 2 (basket) is increased to increase the size of the centrifuge, or the inner basket 2 with respect to the extrusion plate 7 is increased. By increasing the supply amount of the processed material to the inner filtration screen 2a that is easily filtered in this way without increasing the time of one stroke of advancing and retreating due to relative movement, more processing is performed in one stroke. The product can be processed reliably and efficiently, and on the other hand, by suppressing the supply of the processed product to the inner filtration screen 2a which is difficult to be filtered, a uniform cake can be formed over the entire length of the inner basket 2. It becomes possible to form. And along with these, it is possible to reduce the equipment cost and installation space of the centrifugal separator, simplify the foundation of installation by reducing the weight of the equipment, and perform post-treatment of the filtered cake stably and easily. Become.

  In this embodiment, in order to set the moving speed of the inner basket 2 with respect to the pushing plate 7 as described above, as the advancing / retreating driving means 11 for advancing / retreating the inner basket 2 via the pushing shaft 6, driving means by an electric motor 11a is used. Is used. However, for example, even when the push shaft 6 and the inner basket 2 are advanced and retracted by hydraulic drive as in the prior art, a difference is made in the flow diameter of the hydraulic oil at the time of forward movement and backward movement, and a speed controller is installed. It is possible to set the moving speed by setting a difference in the hydraulic oil discharge speed by bypassing the cylinder discharge side flow path, but in this case, the forward / backward movement specific to the hydraulic drive is possible. There is a problem that the hydraulic pressure becomes unstable at the time of switching, and it may be difficult to reliably set the predetermined relative movement speed.

  On the other hand, the advancing / retreating drive means 11 by the electric motor 11a as in the present embodiment has high responsiveness, can change the moving direction quickly even when switching between advancing and retracting, and the moving speed is also reliable and stable. This is particularly suitable when the relative movement speed of the inner basket 2 with respect to the push-out plate 7 is set to different magnitudes as in the centrifuge and the centrifuge method of the above configuration.

  The forward / backward drive means 11 by the electric motor 11a is not limited to the electric cylinder that converts the rotation of the electric motor 11a into the linear motion of the piston rod by the screw shaft and the nut as in the above embodiment, but an electric linear motor. A linear cylinder that directly moves the piston rod by linear movement, and two or more chains are meshed with each other, and are moved forward by an electric motor in a columnar shape. An actuator or the like can also be used.

  Next, FIGS. 4 and 5 show a second embodiment of the centrifuge of the present invention. The same reference numerals are assigned to the parts common to the centrifuge of the first embodiment. Description is omitted. Further, in the centrifuge of the second embodiment shown in FIGS. 4 and 5, the other end portion in the direction of the axis O (not shown) is the same as that of the centrifuge of the first embodiment. Omitted.

  That is, in the first embodiment, the inner basket 2 is accommodated in the outer basket 1 and can be rotated integrally, and the inner basket 2 is attached to the extrusion shaft 6 and advanced and retracted in the direction of the axis O. 1 and the extrusion plate 7 supported thereby are held at a fixed position in the direction of the axis O, so that the extrusion plate 7 can move relative to the basket (inner basket 2) in the direction of the axis O. On the other hand, in the second embodiment, a single basket 21 having a filter screen 21a at the body and an open end 21b at one end in the direction of the axis O is provided at one end of the main shaft 5 via a holding plate 21c. At one end of the extrusion shaft 6 that is attached and held at a fixed position in the direction of the axis O and is inserted into the holding plate 21c, an outer diameter extrusion plate 22 that can slide in contact with the inner peripheral surface of the filtration screen 21a. By attached to the shaft to advance and retreat in the axial O direction, and is movable relative to the direction of the axis O relative to the basket 21.

  Therefore, as in the second embodiment, when the basket 21 and its opening end 21b are fixed in the axis O direction and the pusher plate 22 is movable back and forth in the axis O direction, The direction in which the distance between the extrusion plate 22 and the opening end 21b of the basket 21 in the direction of the axis O is increased is the direction when the extrusion plate 22 is retracted, and the direction in which the interval is decreased is the direction when the extrusion plate 22 is advanced. Become.

  Also in this embodiment, the relative movement speed of the extrusion plate 22 and the basket 21 in the direction of the axis O is such that the extrusion plate 22 shown in FIG. From the state in which the distance D in the direction of the axis O with respect to 21b is small, the direction in which the distance D in the direction of the axis O between the extrusion plate 22 and the opening end 21b of the basket 21 increases, that is, the direction in which the extrusion plate 22 moves backward. The relative movement speed is higher than the relative movement speed in the direction in which the distance D shown in FIG. 4 decreases from the state where the distance D in the direction of the axis O between the extrusion plate 22 and the opening end 21b shown in FIG. It is set to be smaller.

  For this reason, also in this embodiment, when the extruded plate 22 moves backward after extruding the processed material deposited on the inner peripheral surface of the filtration screen 21a, the state in which the accumulated amount after the processed material is extruded is less likely to be filtered. Since a new processed material supplied from the supply pipe 9 is slowly accumulated on the inner peripheral surface of the filter screen 21a over time, a large amount of processed material is efficiently filtered. can do. On the other hand, when the extruded plate 22 is pushed out and the distance D from the opening end 21b becomes small when pushing out the accumulated processed material, the moving speed is large, and the processed material added on the already accumulated processed material is reduced. Therefore, a uniform cake can be formed over the entire length of the basket 21.

  Note that, as in the first and second embodiments, the relative movement speed in the direction of the axis O with respect to the baskets 2 and 21 of the extrusion plates 7 and 22 is the relative movement speed in the direction in which the interval D in the direction of the axis O increases. However, when the ratio is set to be smaller than the relative movement speed in the direction in which the interval D is reduced, if the ratio is too large, it is difficult to set the movement speed of the moving basket (inner basket 2) and the extrusion plate 22. Therefore, there is a risk that a large amount of processed material cannot be reliably supplied to the filtration screens 2a and 21a that are easily filtered, or a large amount of processed material is added to the filtration screens 2a and 21a that are difficult to be filtered. Arise.

  Therefore, the relative movement speed in the direction in which the distance D in the axis O direction between the extrusion plates 7 and 22 and the open ends 2b and 21b of the baskets 2 and 21 increases is the relative movement speed in the direction in which the distance D decreases. On the other hand, it is desirable to set so as to decrease at a speed of 1/4 or more. However, even if the difference between the relative movement speeds is small, the above-described action may not be effectively achieved. Therefore, the relative movement speed in the direction in which the distance D increases becomes relatively small. It is more desirable to set it to 2/3 or less with respect to the moving speed. In the first embodiment, the present invention is applied to a centrifuge having a two-stage basket of an outer basket 1 and an inner basket 2, and a centrifuge having a single basket 21 and a centrifuge method in the second embodiment. Although the case where it applies is demonstrated, of course, it is also possible to apply this invention to the centrifuge which has a basket of three or more steps, and the centrifuge method.

DESCRIPTION OF SYMBOLS 1 Outer basket 1a Outer filtration screen 1b Open end of outer basket 1 2 Inner basket (basket)
2a Inner filtration screen 2b Open end of inner basket 2 3 Casing 5 Main shaft 6 Extrusion shaft 7, 22 Extrusion plate 8 Dispersion plate 9 Processed material supply pipe 10 Bearing box 11 Advance / retreat driving means 11a Electric motor 11b Cylinder box 21 Basket 21a Filtration screen 21b Open end of basket 21 O Axis of rotation of basket 21 (outer basket 1, inner basket 2) D Distance between push plates 7, 22 and inner basket 2, open ends 2b, 21b of basket 21 in the direction of axis O

Claims (4)

A cylindrical basket provided with a filtration screen on the body and rotated about an axis, and accommodated in the basket and rotatable integrally with the basket, and can be moved relative to the basket in the axial direction. A centrifuge for discharging the cake filtered by the filter screen from the processed product supplied into the basket to the opening end side of the basket by the extrusion plate, and discharging the cake.
The relative movement speed in the axial direction between the extrusion plate and the basket is such that the relative movement speed in the direction in which the axial distance between the extrusion plate and the open end of the basket is increased is the extrusion plate and the basket. A centrifugal separator characterized by being set so as to be smaller than a relative moving speed in a direction in which the distance between the opening end and the axial direction becomes smaller.   The relative movement speed in the direction in which the axial distance between the extruded plate and the open end of the basket is increased is relative to the direction in which the axial distance between the extruded plate and the open end of the basket is decreased. 2. The centrifugal separator according to claim 1, wherein the centrifugal separator is set so as to decrease at a speed of 1/3 or more with respect to the moving speed. A processed product is supplied into a cylindrical basket provided with a filter screen in the body and rotated about its axis, and cake filtered from the processed product by the filter screen is contained in the basket and integrated. A centrifugal separation method for extruding and discharging to the open end side of the basket by an extrusion plate that is rotatable and relatively movable in the axial direction relative to the basket,
The relative movement speed in the axial direction between the extrusion plate and the basket is set to be a relative movement speed in the direction in which the interval between the extrusion plate and the opening end of the basket is increased in the axial direction. The centrifugal separation method is characterized in that the centrifugal separation method is set so as to be smaller than a relative moving speed in a direction in which the distance between the opening end and the axial direction becomes smaller.   The relative movement speed in the direction in which the axial distance between the extruded plate and the open end of the basket is increased relative to the direction in which the axial distance between the extruded plate and the open end of the basket is decreased. 4. The centrifugal separation method according to claim 3, wherein the centrifugal separation method is set so as to decrease at a speed of 1/3 or more with respect to the moving speed.

Images