KR100823701B1 - Continuous filtration device with pivoting cells - Google Patents

Abstract

The present invention relates to a continuous fluid filtration device, comprising: (i) a filtration cell (1) disposed in the shape of a rotary conveyor around a rotating shaft, each of which is arranged to be able to rotate around a tangential rotating shaft (3), and (ii) Means for removing the filtrate from the cell (1). The latter means comprises at least one outlet 42 at the bottom of each cell, a central collector and connecting means having a flexible conduit 38. According to the present invention, no portion of the flexible conduit 38 in the cell filtration position is located lower than the other portion downstream of the filtrate flow. The flexible conduit 38 is arranged so that it does not stretch during the rotational movement of the cell.

Description

CONTINUOUS FILTRATION DEVICE WITH PIVOTING CELLS

The present invention relates to a continuous fluid filtration device,

A filter bed and a bottom, each having an opening facing upwards, through which the fluid to be filtered is fed, passing the filtrate at the filtration position and filtering the filter dregs, which are installed on a rotary conveyor around the axis of rotation, respectively A filtration cell arranged to rotate around a tilt axis that is in contact with a horizontal circle having a rotation axis in a center thereof;

Means for supporting the filtration cells such that each cell can effect rotation about an axis of rotation;

Filter cell drive means for driving each cell to rotate about a rotation axis;

Filter cell rotation means for causing a rotational movement around the tilt axis during rotation around the axis of rotation, and

Means for discharging the filtrate from the cell comprising at least one outlet orifice below each cell and a central collector and connecting means for transferring the flow of filtrate between the at least one outlet orifice and the collector. .

Filtration devices with cells on a rotary conveyor, especially used for the production of phosphoric acid, have long been known. Among others, US-A-3.389.800, BE-A-768591, BE-A-847088, US-A-4.721.566, WO-90 / 13348 and WO 92/20426 can be cited as patents or patent applications. have.

All these documents describe a filtration process in which a planar trapezoidal filtration cell rotates on a rotary conveyor around the axis of rotation and rotates about a radial axis at a given moment to allow for the discharge of filtration waste and cleaning of the cell.

Given the rotation around this horizontal radial axis, sufficient space must be given between adjacent cells to enable the aforementioned rotation without collision between these cells.

The result is a loss of filter surface and thus a loss of device performance.

Filtration devices of the type described in the introduction have also already been provided (see eg US-A-1028789). This device has the disadvantage that it is concentric with the tilt axis of the cell and requires the flow of the filtrate through the rotating joint forming part of the bearing. Such joints inevitably increase the wear of the frictional part and must provide air holes in the vacuum circuit, causing cooling and crystallization of the filtrate in the circuit. In addition, a complex cell turning structure is located below the cell, where there is a risk of corrosion due to the inevitable contact with the corrosive fluid entering the cell.

The filtration device is also known to rotate the cells on the rotary conveyor about the tangential axis (see US-A-2768753). In this apparatus, the collector is located outside the filtration cells with respect to the axis of rotation in the plane, and the outlet orifice of each cell is located directly in this collector and connected to the vacuum source by sliding. No compressed gas source is provided for the removal of solids from the filtration bed in the pivot position or for cleaning. The discharge of the solid material is effected by the impact and stopping of the rotational movement in the stopper.

It is an object of the present invention to avoid this drawback, which requires a significantly reduced force to drain and clean the filter debris from the cell, and is a relatively simple and inexpensive device capable of discharging without outflow of the filtrate and without excessive wear of the discharge means. To provide.

In order to solve this problem, according to the present invention, there is provided a filtration device as described in the introduction, wherein the connecting means for each cell is provided at the filtration position of the cell, with any part downstream of the filtrate flow. A flexible conduit not positioned lower than the other part located, wherein the flexible conduit is arranged such that no expansion occurs during rotation of the cell.

The device allows the cell to rotate with its side edges kept equidistant. Thus, by reducing the separation between cells to the maximum possible range, it is possible to bring them closer to the center of the cell, and also to increase the overall filtering surface of the device to the same size, or to keep it at the same value at a fairly small size. Make it possible. Also, through this arrangement, the filtered fluid flows continuously through the flexible conduit without deceleration. The flexible conduit does not occur any expansion during rotation, and is given its arrangement between the outlet orifice of the cell and the centrally located collector, and the flexible conduit also does not suffer any twisting during rotation of the cell. Thus, the fatigue of the connecting means is minimized.

According to one embodiment of the invention, in the radial cross section through the device, in the filtration position of the cell the flexible conduit extends downward along an almost vertical axis from the outlet orifice, such that the collector is inclined downward from a height lower than the tilt axis. In the direction of rotation of the cell, the flexible conduit extends almost horizontally from the exit orifice to the tilt axis and then angles towards the collector.

Preferably, the tilt axis is supported on at least one bearing having a first outer diameter D1, wherein the flexible conduit has a second outer diameter D2, wherein the distance E between the tilt axis and the above described substantially vertical axis of the flexible conduit is , Greater than or equal to zero and less than or equal to D1 + D2. This arrangement as close as possible between the tilt axis and the vertical axis of the conduit preferably prevents the flexible conduit from receiving expansion forces during rotation.

According to an improved embodiment of the invention, the device has a support for each flexible conduit which rotates around the axis of rotation with the filtration cell. In this way, this support prevents the flexible conduit from under its own weight or under its weight as the filtrate flows, at any point in the direction of the collector and no longer inclined downward and inclined downward. .

According to a particular embodiment of the present invention, the collector is connected to a source of negative pressure in communication with the cell bottom filter bed by a flexible conduit connected to the filtration cell at the filtration position, which also removes the filter dregs from the filter bed. It is a distributor connected to a source of compressed gas in communication with the cell by means of a flexible conduit connected to the filtration cell in a rotational position to assist.

According to another embodiment of the present invention, the movement means includes a roller disposed in each cell so as to freely rotate about a rotation axis, and a roller of each filtration cell driven and causing the rotational movement of the cell. And a guide rail fixedly disposed at a position of the filtration device, which guides the roller in order.

Other embodiments of the device according to the invention appear in the appended claims.

Other details and features of the present invention will become apparent from the following additional and non-limiting embodiments with reference to the accompanying drawings.

1 is a partial cutaway plan view of a filtration device according to the invention,

2 is a cross-sectional view taken along the line II-II of FIG.

3 is an enlarged plan view of the guide rail along the line III-III of FIG. 2;

4 is an enlarged cross-sectional view of the guide rail along the line IV-IV of FIG. 2;

5 is a detailed enlarged view of the left part of FIG. 2;

6 is a cross-sectional view along the line VI-VI of FIG.

7 a variant of the configuration provided in FIG. 6,

FIG. 8: is sectional drawing along the VIII-VIII line | wire of FIG.

These drawings are shown schematically, and in other respects, many elements have been omitted for clarity.                 

In the several figures, identical or similar elements have been represented by the same reference numerals.

In the embodiment shown in FIGS. 1 and 2, a bowl-shaped filtration cell 1 with an opening facing upwards during filtration is arranged on a rotary conveyor around the vertical axis of rotation 2. This cell 1 is provided with a horizontal filter bed 41 which is supplied with a fluid to be filtered thereon and a filtrate collected below.

According to the invention, each cell 1 can rotate around the tilt axis 3, which tilt axis is arranged such that its center is in contact with the virtual horizontal circle 4 formed on the rotation axis 2.

In the illustrated embodiment, the lower part 45 of each cell 1 is provided with two bearings 5, 6 through which the shaft 7 passes so that the cell can freely rotate. This shaft 7 is concentric with the tilt axis 3 described above.

As shown in FIGS. 1 and 2, the shaft 7 is supported by two support links 8, 9, each of which is connected by a rod 10, 11, 12, 13 arranged in a triangle. Is formed. At one end, the rods 10, 11 are secured to a ring 14 surrounding the shaft 15 so that it can freely rotate around it without contact with the shaft. This central axis 15 is concentric with the rotation axis 2. At the other end, the rod 10 is connected to the shaft 7 and the rod 11 is connected to a circular rotating chassis 16 provided with a shelf. The rod 13 connects the shaft 7 to the circular chassis 16, and the rod 12 connects the circular chassis with the central portion of the rod 10. Each cell is thus supported by two lightweight and undeformed structures, so that only traction and compression forces act.

The circular chassis 16 arranged concentrically with the rotating shaft 2 is supported by a set of rollers having horizontal and vertical axes 17 and 18, respectively, and can be guided and rotated in a horizontal plane around the rotating shaft 2. In the embodiment shown, the drive motor 19 actuates the pinion 20 with teeth engaging with the shelves of the circular chassis 16. When the motor starts to run, drive the whole device to rotate in the direction of arrow F.

Each filtration cell is provided with a roller 21 arranged in the direction toward the center of the device in the embodiment shown. The roller 21 is arranged to freely rotate around the rotation shaft 22. This axis 22 preferably extends radially between the axis of rotation 2 of the central device and the tilt axis 3 of the corresponding cell in the plane when the cell is in the horizontal position.

Preferably, the rotational axis 22 of the roller 21 passes through the rotational axis 2 of the device throughout the rotational movement of the cell and in a plane perpendicular to the tilt axis 3 of the cell corresponding to the roller. Is located.

In the part located at the right side of the apparatus in FIG. 1 a guide rail 23 is arranged to receive the rollers 22 of each driven filtration cell.

In the illustrated embodiment, the guide rail 23 is supported by two brackets 24 and 25 on the filtration cell, and the center-facing end of the bracket is supported by the cross-member 26. Each leg 27 with suspension clamp 43 rigidly supports the guide rail 23 floating above the filtration cell. The rail 23 has a U shape in the top view of FIG. 1 and includes a central portion 30 and two side branches 28, 29.

This guide rail 23 is formed in the embodiment shown, with two side walls 31 and 32 extending in parallel along the entire path of the rail. Between these two walls, the roller 21 follows in the direction of forward movement shown by the arrows in FIG.

As shown in FIGS. 1 and 2, when the roller 21 of the filtration cell reaches the central portion 30 of the guide rail 23, the cell is in a nearly vertical position.

In the embodiment shown, a place for cleaning the filter bed 41 and the back of the cell are provided. It comprises two lances 33, 34 provided with a spray nozzle and provided with a cleaning liquid. This lance sprays this fluid into the filtration cell, and the nearly vertical position of the filtration cell discharges the sprayed fluid to the collection vessel (not shown) by gravity.

Each filtration cell is preferably provided with means for adjusting its leveling. This means has, in the embodiment shown, a projection 35 extending downward from the edge of the cell disposed towards the center of the device. This protrusion is provided with an edge having a through hole into which the through rod 36 can be screwed. This through rod 36 whose end is adjusted for length by screw adjustment is supported by a stopper 37 extending between two rods 10 of the links 8, 9 supporting the filtration cells.

Supplying the fluid to be filtered to the filtration cell is a general method through the top of the cell. The filtrate is discharged through an orifice 42 located under each cell. This orifice is connected to the central collector / distributor 39 by a flexible conduit 38.

As is apparent from FIG. 5 showing a radial cross section through the device according to the invention, the flexible conduit 38 is shown in solid lines in the filtration position of the cell and in dashed lines in the rotational position. In the filtration position, it extends downward along an almost vertical axis 46 from the outlet orifice. Only when passing a height lower than the tilt axis 3, the flexible conduit 38 is angled in the direction of the center collector 39 so that it can have a continuous downward slope. Thus, through its own weight and through the weight of the filtrate it receives, the conduit does not try to bend down and does not have a low position for poor flow, and in the embodiment shown in FIG. 38 is partially supported by channel 40 that rotates with the cell. In the embodiment shown in FIG. 5, it is the case with a local support 47 supporting the flexible conduit 38 at its central portion.

The slope of the flexible conduit may vary, but is greater than 0 ° anywhere.

As shown in FIG. 5, the length L of the flexible conduit between the outlet orifice 42 and the support 47 remains constant even when the cell is in the pivot position, while the flexible conduit deforms. The portion of the flexible conduit 38 between the support 47 and the collector 39 is not deformed and therefore its length does not change.

In the pivoting position, the flexible conduit extends almost horizontally from the outlet orifice 42 to the tilt axis 3 distance and then angles in the direction of the collector 39.

As shown in FIGS. 5 and 6, the bearing 6 has an outer diameter Dl and the flexible conduit has an outer diameter D2. In the embodiment shown, the distance E between the tilt axis 3 and the nearly vertical axis 46 of the conduit is preferably (D1 + D2) / 2. Thus, although this is not important, this distance E may be larger, but preferably equal to D1 + D2, as close to or as large as possible.

Consider the embodiment shown in FIGS. 7 and 8. Here, the cells are concentric with each other and pivot around the shaft ends 48, 49 concentric with the tilt axis 3, and the bearings 5, 6 have an axial offset axis 50 to form a kind of crankshaft. Is kept in a remote position. The axis 46 intersects the tilt axis 3 here and the distance E is zero.

Thus, it may be conceivable that the axis 46 is located further outward with respect to the tilt axis 3 in plan view.

The operation of the illustrated device is described below.

The motor 19 drives the lathe on the circular chassis 16 to rotate, with each filtration cell rotating in the F direction.

The cells are positioned horizontally adjacent to each other and filled with the fluid to be filtered. Filtration of the fluid takes place under the negative pressure obtained by means originally known in a general manner through the filter bed 41.

Filtrate in each cell is discharged through the corresponding flexible conduit 38, and the filter dregs are formed on the filter bed. The flexible conduit 38 is arranged to have a continuous downward slope so that the discharge is easy and quick without the area where the filtrate is aggregated or crystallized. Avoid friction and abrasion where it is easy to allow spills and air ingress. The negative pressure is connected without loss from the collector of filtrate 39 to the bottom distance of each cell in the filtration position.

At this time, the roller 29 of the cell meets the guide rail 23 as shown in FIG. 3. The rails forcibly raise the rollers to allow the cells to rotate. Its inner end pivots up with respect to the tilt axis 3. At about half the position of the bracket 28 of the rail 23, the center of gravity of the cell passes perpendicular to the tilt axis 3.

If this is exceeded, the cell cooperates with the drive until the weight reaches the center portion 30. Similarly, during movement towards the branch 29 of the guide rail, once the cell's center of gravity passes perpendicular to the tilt axis 3, the weight of the cell cooperates with its drive.

When the roller 21 follows the central part passage of the guide rail 23, the cell is in an almost vertical position, and so is the filter bed.

During this rotation, the flexible conduit 38 moves from the position shown by the solid line in FIG. 5 to the position shown by the broken line. If there is a deformation to the top of the flexible conduit 38, no extension of it, no bending about its longitudinal axis can be observed. Thus, fatigue is reduced to a minimum.

The filtration debris all fall first to the largely inclined outer wall 44 of the cell and are collected by a collector (not shown), and the cell is once again rotated to a horizontal position to clean the previously described cleaning before beginning the filtration cycle. Pass through the place.

Preferably, such a facility may be provided in a conventionally known manner to set a slight back air pressure in each cell to assist in the discharge of the filter debris when the cell is in the vertically rotated position. This back pressure may later be provided to the bottom of the cell through a flexible conduit 38 from the collector 39 which acts as a distributor.

The present invention is not limited to the above-described embodiments, and many variations are possible within the scope of the appended claims.

Claims (12)

A filter bed (41) and a lower (45), each having a top facing opening, through which the fluid to be filtered is fed, passing the filtrate at the filtration position and filtering out the filter residues; A filtration cell (1) disposed on a rotary conveyor of the rotary conveyor and disposed so as to be able to rotate around a tilt shaft (3) in contact with a horizontal circle (4) having a rotary shaft (2) at its center; Means (8, 9) for supporting the filtration cells so that each cell can carry out rotation about the axis of rotation (2), Filter cell drive means (16, 19, 20) for driving each cell to rotate around the axis of rotation (2), Filter cell rotation means for causing a rotational movement around the tilt axis 3 during rotation around the axis of rotation, and A cell (1) comprising at least one outlet orifice (42) under each cell and a central collector (39) and connecting means for transferring a flow of filtrate between the at least one outlet orifice (42) and the collector (39). Means for discharging the filtrate from The connecting means for each cell comprises a flexible conduit 38 in which no part of it in the filtration position of the cell is lower than the other part located downstream with respect to the filtrate flow, the flexible conduit 38 of the cell Continuous fluid filtration device, characterized in that arranged so that no extension occurs during rotation. 2. A radial cross section through the device according to claim 1, wherein in the filtration position of the cell the flexible conduit (38) extends downwardly along the vertical axis (46) from the outlet orifice (42) and the tilt axis (3). Angled in the direction of the collector 39 to have a continuous downward slope from a lower height, in the pivoting position of the cell the flexible conduit 38 extends horizontally from the outlet orifice 42 to the tilt axis 3. Extend, and then angle in the direction of the collector (39). 3. The tilt shaft (3) according to claim 2, wherein the tilt shaft (3) is supported by at least one bearing (5, 6) having a first outer diameter (D1), and the flexible conduit (38) has a second outer diameter (D2). And the distance E between (3) and said vertical axis (46) of the flexible conduit (38) is greater than or equal to zero and less than or equal to D1 + D2. The device according to claim 2, characterized in that the vertical axis (46) is located between the tilt axis (3) and the rotation axis (2) in the radial cross section. 5. The device according to claim 1, wherein each cell is supported by a shaft (7) concentric with the tilt axis (3) and is able to rotate around this axis. 6. 5. The cell according to any one of claims 1 to 4, wherein each of the cells is supported by two shaft ends 48, 49 which are concentric with each other and also with the tilt axis 3 to rotate around this axis. Apparatus, characterized in that. The device according to any one of the preceding claims, characterized in that it is provided with supports (40, 47) for each flexible conduit (38) that rotates around the axis of rotation (2) together with the filtration cells (1). Device. 5. The source of negative pressure according to claim 1, wherein the collector 39 is in communication with the cell lower filter bed 41 by a flexible conduit 38 connected to the filtration cell 1 at the filtration position. 6. And the collector 39 is also connected to a source of compressed gas in communication with the cell by a flexible conduit 38 which is connected to the filtration cell 1 in a pivoting position to help remove the filtration debris from the filter bed. Apparatus characterized in that the dispenser. The filter cell rotating means according to any one of claims 1 to 4, wherein A roller 21 arranged in each cell so as to freely rotate about the rotation shaft 22, and A guide rail 23 fixedly positioned at one position of the filtration device, which receives the roller 21 of each filtration cell that is driven and guides the roller to induce a rotational movement of the cell. Device. 10. The rotating shaft (22) of each of the rollers (21) is characterized in that it passes through the axis of rotation (2) of the apparatus and is located in a plane perpendicular to the tilt axis (3) of the filtration cell corresponding to the roller. Device. Device according to claim 10, characterized in that the roller (21) is received by the cell at its inner end. 10. The filtration surface of the cell according to claim 9, wherein the guide rail (23) is located above the filtration cell to form a planar U-shape and consists of a central portion (30) and two side branches (28, 29). Is in the vertical position when the roller (21) reaches the U-shaped central portion (30).

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