KR100363985B1 - Apparatus for screening debris - Google Patents

Abstract

Industrial Applicability The present invention provides an apparatus for removing impurities that physically removes contaminants contained in influent water from an industrial facility requiring a large amount of water, such as a power plant, an oil refinery, a steelmaking facility, a desalination plant, or a water treatment facility such as a sewage treatment plant, a water purification plant, a wastewater treatment plant, or a pumping plant. It is about.

In the contaminant removal device according to the present invention, a rake 45 is disposed at the rear end of the bar screen 43 that filters the contaminants 41 contained in the influent in the water treatment facility, so that the rake is disposed at the rear end of the bar screen 43. The front guide penetrates the clearance of the bar screen 43, and the main guide roller 47 mounted on the side of the rake 45 is connected to the chain 51, and the auxiliary guide roller 53 to the main guide roller 47. ) Is connected by a guide link 55, the main guide roller 47 moves along the main guide track 57, the auxiliary guide roller 53 moves along the auxiliary guide track 59, The main guide track 57 and the auxiliary guide track 59 are formed in the body 63 fixed to the side wall 61 of the water channel, and the chain 51 defines the upper sprocket 65 and the lower sprocket 67. Circulation, the upper sprocket 65 is connected to the drive 71 by a shaft And that is characterized.

Description

Debris removal device {APPARATUS FOR SCREENING DEBRIS}

Industrial Applicability The present invention provides an apparatus for removing impurities that physically removes contaminants contained in influent water from an industrial facility requiring a large amount of water, such as a power plant, an oil refinery, a steelmaking facility, a desalination plant, or a water treatment facility such as a sewage treatment plant, a water purification plant, a wastewater treatment plant, or a pumping plant. In more detail, the rake is located at the rear end of the bar-screen (bar-screen), the rake that passes the bar screen from the rear end to the front end is moved from the bottom to the upper end of the bar screen ( The present invention relates to an apparatus for removing a contaminant caught in an upstream.

In general, the bar screen 1 is a water treatment facility such as an industrial facility requiring a large amount of water, such as a power plant, an oil refinery, a steelmaking facility, a desalination plant, or a water treatment facility such as a sewage treatment plant, a water purification plant, a wastewater treatment plant, or a pumping station (2) In order to physically remove the contaminants (3) contained in the inflow water flowing in the direction of the arrow in the), a plurality of flat iron (or round bar, wedge wire having a triangular cross-section in the water flow channel 2 (WEDGE WIRE) ) And the like) are spaced apart from each other by a predetermined interval so that the contaminants 3 are caught in the flat iron. Here, the gap between the flat iron and the flat iron is called a clearance (C; clearance), and when the inflow water flows along the channel 2 in the direction of the arrow, the front part of the flat iron, that is, the part where the contaminant 3 is caught, is sheared. It is called upstream and the rear part of the flat iron is called downstream.

2 and 3, in the conventional contaminant removing device, the drive sprocket 6 and the driven sprocket 9 of the drive motor 5 are connected to each other by a chain 7, and the driven sprocket 9 and The upper sprocket 11 located outside the water is connected by a shaft (not shown), the upper sprocket 11 and the lower sprocket 17 located in the water are connected by the chain 21, the chain 21 A plurality of rakes 25 are mounted on the.

In addition, the conventional contaminant removal device configured as described above is installed at the same angle as the bar screen (1) upstream of the bar screen (1) installed inclined about 10 ° to 40 ° with respect to the vertical line (single dashed line). The rake 25 is arranged at the front end of the bar screen 1, and the protrusion 25 ′ of the rake 25 is fitted to the clearance C of the bar screen 1.

In the conventional contaminant removing device as described above, the upper sprocket 11 is rotated by the driving motor 5, whereby the chain 21 circulates between the upper sprocket 11 and the lower sprocket 17. . At this time, the decals 25 installed between the chains 21 move from the lower part to the upper part at the front end of the bar screen 1 to remove the debris 3 caught on the bar screen 1. do. Then, the contaminant 3 of the rake 25 is discharged from the rake 25 to the contaminant discharge container 35 (or the contaminant discharge conveyor) by the wiper device 33.

However, in the conventional dust removal apparatus as described above, the lower sprocket 17 and the body (not shown) supporting the lower sprocket are located at the front end of the bar screen 1 in which the contaminants 3 are not removed. There is a risk of failure due to the inflow of the contaminants 3 into the lower sprocket 17. Since the rake 25 is located at the front end of the bar screen 1, the flow of water is partially interrupted by the flow of water and the vortex is generated. Deteriorate the state of removing the impurities, and because the rake 25 is configured to drag along the inclined surface at the front end of the bar screen 1, the rake 25 attracts and raises the contaminants 3 to the fluid flow. It may fall back into the water by the scavenger, the scavenger may be caught or dropped into the gap between the upper support plate 37 and the tip of the rake, the rake driver to completely remove the contaminant (3) The cycle must be operated several times, and the bar screen (1) must be installed at an angle of about 10 to 40 degrees with respect to the vertical line. Therefore, it takes up a lot of installation space and has the structure of the bar screen itself to maintain the shape of the bar screen. There was a problem that the bottom and top of the bar screen (middle point if necessary) had to be supported by the concrete structure.

Therefore, an object of the present invention is installed in the rear end of the bar screen to solve the conventional problems as described above, the rake that passes the bar screen from the rear end to the front end is caught on the front end of the bar screen while moving from bottom to top. It is to provide a debris removal device for removing the debris.

One example of the contaminant removal device according to the present invention for achieving the above object is a rake is mounted on the rear end of the bar screen to filter the contaminants contained in the influent in the water treatment facility, the clearance of the bar screen from the rear end of the bar screen to the front end A main guide roller mounted on the side of the rake, connected to the chain, an auxiliary guide roller connected to the main guide roller by a guide link, the main guide roller moving along the main guide track, The auxiliary guide roller moves along the auxiliary guide track, the main guide track and the auxiliary guide track being formed in a body attached to the side wall of the water channel, the chain circulates the upper sprocket and the lower sprocket, and the upper sprocket is driven by the shaft. It is characterized in that connected to the drive.

Bar screen of the debris removal device according to the invention is about 9 ° in the vertical ?? It is inclined by an angle, the lower end of which is supported on the bottom of the concrete channel, a semi-circular curved portion is formed on the upper end, the end of the curved portion is supported by the supporting means or the concrete structure, and the driving means is operated by the control panel. It is controlled and characterized in that the debris is automatically discharged from the rake when the rake is moved by an upper bend without a separate debris removal wiper device.

The main guide track of the contaminant removing device according to the present invention has an upper end higher than the upper end of the auxiliary guide track, and a lower end of the auxiliary guide track is formed lower than the lower end of the main guide track, and the upper sprocket is embedded inside the semicircular curved portion of the bar screen. The lower sprocket is supported by the body at the lower rear end of the bar screen, and the upper sprocket and the lower sprocket have the same diameter.

The drive device is preferably installed inside the curved portion of the bar screen, but is not limited thereto and may be installed outside.

Another example of the dust removal apparatus according to the present invention is the bottom of the bar screen for filtering the impurities contained in the influent in the water treatment plant is installed on the bottom of the concrete channel in the direction perpendicular to the fluid flow, the top of the bar screen is hinged at the intermediate site Supported by a bar-space, a rake that lifts up the debris trapped in the bar screen is disposed at the rear end of the bar screen to penetrate the clearance of the bar screen, and the rake is mounted on a chain circulating the upper sprocket and the lower sprocket. The upper sprocket is driven by a drive unit, and a weight wiper is provided on the body to remove the impurities caught by the rake, the upper sprocket is installed in the body, and the lower sprocket is located at the lower portion of the rear end of the bar screen. Supported by both bodies attached to the side wall, the drive means being driven by a control panel Operation is controlled, and the debris removed by the weighted wiper is discharged to a debris discharge bin or a debris discharge conveyor.

The rake is disposed in a state in which the back plate is inclined by a predetermined angle with respect to the horizontal direction of the rake rearward, the side plate of the rhombus shape is attached to both sides, the connection portion is connected to the chain in the center of the side plate It is done.

The back plate pushes out the hinged bar space when the rake passes through the hinged bar space, and the upper edge of the side plate guides the movement of the weighted wiper when the rake passes through the weighted wiper do.

The hinged bar space is rotated by a predetermined angle when the rake passes in the state of supporting the bar screen, and after the rake passes, it is returned to its original position by its own weight to support the bar screen.

When the rake rises, the end of the rake first touches the end of the rake back plate, and when the rake rises further, the weight of the wiper discharges the trash from the rake to the trash discharge bin or the trash discharge conveyor. It is characterized by.

Another example of the debris removal device according to the present invention is installed on the bottom of the concrete channel in the form of the lower portion of the bar screen for filtering the contaminants contained in the influent in the water treatment plant inclined by β angle of 15 degrees from the vertical, bar screen The upper part is supported by the hinged bar-space at the middle part, and a rake for lifting up the contaminants caught in the bar screen is disposed at the rear end of the bar screen to penetrate the clearance of the bar screen, and the rake is connected to the upper sprocket. It is mounted on the chain circulating the lower sprocket, the upper sprocket is driven by the drive, the wiper for removing the impurities caught by the rake is supported on the body after the upper sprocket, the upper sprocket is installed in the body, the lower sprocket Is supported on both bodies attached to the side wall of the channel under the rear end of the bar screen. Said said drive means is a control operation by the control panel, it is characterized in that the impurities of the rake by the wiper discharged to the contaminants discharging tube or a conveyor.

The hinged bar space supports the load added to the bar screen by the flow velocity, water head difference, etc., and when the rake moves up to filter the contaminants caught on the bar screen, the hinged bar space can be rotated by a predetermined angle to secure the path of the rake. After the rake passes, it is returned to its original position by its own weight to support the bar screen.

The wiper has a shock-absorbing structure that allows the rake to contact the wiper while the rake passes through the upper sprocket and passes through the return guide track to drop the contaminants from the top of the rake without impact and return to the home position again. do.

The upper sprocket has a larger diameter than the lower sprocket, and the chain passing through the upper sprocket is circulated to the lower sprocket along the return guide track.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic diagram showing a state in which a bar screen is generally installed in a channel of a water treatment facility;

Figure 2 is a schematic side view showing a state in which a conventional contaminant removal device is installed at the front end of the bar screen

Figure 3 is a cross-sectional view taken along the line A-A of Figure 2 showing a state in which the rake of the conventional debris removing device between the bar screen

4 is a schematic side view of an apparatus for removing a contaminant according to a first embodiment of the present invention;

5 is a cross-sectional view taken along the line B-B of FIG.

6a to 6e is a process diagram showing the operation of the contaminant removing apparatus according to the first embodiment of the present invention

7 is a schematic side view showing an apparatus for removing a contaminant according to a second embodiment of the present invention.

8 is a cross-sectional view taken along the line C-C of FIG.

9 is a perspective view showing a rake of a complex removing device according to a second embodiment;

FIG. 10 is a detailed view showing a state in which a contaminant is removed from a rake by a wiper in an apparatus for removing a contaminant according to a second embodiment of the present invention.

11a to 11e is a process diagram showing the operation of the debris removal device according to a second embodiment of the present invention

12 is a schematic side view showing an apparatus for removing a contaminant according to a third embodiment of the present invention.

FIG. 13 is a cross-sectional view taken along the line D-D of FIG. 12.

14A to 14E are process diagrams showing the operation of an apparatus for removing a contaminant according to a third embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

41, 101, 151: Miscellaneous matter 43, 103, 153: bar screen

45, 107, 157: pitchfork 47: main guide roller

51, 113, 163: chain 53: auxiliary guide roller

55: guide link 57: main guide track

59: auxiliary guide track 61: the side wall of the waterway

63, 119, 169: Body 65, 109, 159: Upper sprocket

67, 111, 161: lower sprocket 71, 115, 165: drive device

105, 155: hinged bar space

4 and 5, in the contaminant removing device according to the present invention shown in Figs. 4 and 5, the elements mounted on both sides of the channel are symmetrical with each other. Therefore, only the elements of either end with respect to the rake will be described. In the contaminant removal device according to the first embodiment of the present invention, the rake 45 is disposed at the rear end of the bar screen 43 for filtering the contaminants 41 contained in the influent in the water treatment facility. It passes through the clearance C of the bar screen 43 from the end to the front end. The main guide roller 47 mounted on the side of the rake 45 is connected to the chain 51, and the auxiliary guide roller 53 is connected to the main guide roller 47 by the guide link 55. The main guide roller 47 moves along the main guide track 57, the auxiliary guide roller 53 moves along the auxiliary guide track 59, and the main guide track 57 and the auxiliary guide track ( 59 is formed in the body 63 attached to the side wall 61 of the waterway. In addition, the chain 51 circulates through the upper sprocket 65 and the lower sprocket 67, the upper sprocket 65 is connected to the drive unit 71 by a shaft (not shown).

The bar screen 43 is inclined by an α angle of about 9 ° from the vertical, the lower end is supported on the concrete channel bottom 62, the curved portion 44 is formed in a semi-circular curved upper portion is formed, the curved portion 44 ) Is supported by support means (or concrete structures; not shown). In addition, the catch 41 of the rake 45 is discharged to the catch discharge bin 81 (or the catch discharge conveyor) after the rake 45 passes through the curved portion 44 of the bar screen 43.

In FIG. 5, the upper end of the main guide track 57 is formed higher than the auxiliary guide track 59, and the lower end of the auxiliary guide track 59 is formed lower than the main guide track 57. In addition, the upper sprocket 65 is embedded inside the semicircular curved portion 44 in the bar screen 43, and the lower sprocket 67 is supported by the body 63 at the lower rear end of the bar screen 43. The upper sprocket 65 and the lower sprocket 67 have the same diameter.

The driving device 71 may be installed inside or outside of the curved portion 44 of the bar screen 43, and is driven by the chain 75 to the driving motor 73 and the sprocket of the driving motor 73. It consists of a drive sprocket 77 to be connected. The drive sprocket 77 is connected to the upper sprocket 65 by a shaft (not shown). In addition, the driving motor 73 of the driving device 71 is controlled by the control panel 79.

The control panel 79 may automatically or manually control the operation of the driving device 71. In the automatic operation, the control panel 79 may operate by the water level difference between the front and rear ends of the bar screen 43, and by the timer. The two can be controlled by the combined operation, and the level switch LEVEL SWITCH can be installed only at the front end of the bar screen 43 to control the operation by the water level.

6A to 6E, the operation of the contaminant removing device according to the first embodiment of the present invention will be described.

When the drive unit 71 is operated by the control of the control panel 79, the upper sprocket 65 is rotated in the clockwise direction, and the chain 51 circulates the upper sprocket 65 and the lower sprocket 67, By this, the main guide roller 47, the auxiliary guide roller 53, and the rake 45 are moved as follows.

As shown in FIG. 6A, the rake 45 discharges the contaminant 41 from the curved portion 44 of the bar screen 43 to the contaminant discharge container 81, and then waits for the next removal operation to start (waiting for operation). Start the process. At this time, the end of the rake 45 is parallel to the bar screen 43. Then, when the operation starts, the main guide roller 47 moves to the center position of the lower sprocket 67 while the rake 45 maintains the position shape of the stationary state as shown in FIG. 6B. As shown, as the auxiliary guide roller 53 moves further down the main guide roller 47, the main guide roller 47 moves along the main guide track 57, and by the mechanical configuration of the link, the rake 45 6) is inserted into the clearance of the bar screen 43 while rotating and advancing toward the bar screen 43 so as to be in a state where the contaminants 41 caught on the bar screen 43 can be removed. As shown, the rake 45 moves up from the bottom to the top along the clearance c of the bar screen 43, pulling up the debris 41 caught on the bar screen 43. Then, as shown in FIG. 6E, when the main guide roller 47 rotates along the main guide track 57 at the upper position of the bar screen 43, the rake is performed by the auxiliary guide roller 53 and the guide link 55. 45 changes in a state parallel to the bar screen 43 at a vertical angle while drawing a semicircle. In this process, the impurities 41 contained in the rake 45 naturally fall down along the curved portion 44 of the bar screen 43 by the semicircle shape of the curved portion 44 of the bar screen 43. ) Thereafter, it is again placed in the stopped state (operation standby state) shown in Fig. 6A.

Referring to FIGS. 7 and 8, in the contaminant removing device according to the second embodiment of the present invention illustrated in FIGS. 7 and 8, the elements mounted on both the right and left sides of the channel are symmetrical to each other. Therefore, only the elements of either end with respect to the rake will be described.

In the contaminant removal device according to the second embodiment of the present invention, the bar screen 103 for filtering the contaminants 101 contained in the influent in the water treatment facility is fixed to the concrete channel bottom 104 in a direction perpendicular to the fluid flow. The top of the screen 103 is supported by the hinged bar-space 105. A rake 107 that lifts up the contaminant 101 caught by the bar screen 103 is disposed downstream of the bar screen 103 to penetrate the clearance C of the bar screen 103, and The rake 107 is mounted to the chain 113 circulating the upper sprocket 109 and the lower sprocket 111. The upper sprocket 109 is driven by the drive unit 115, the weight type wiper 117 is supported on the body 119 to remove the contaminants 101 filtered by the rake 107, the upper sprocket 109 ) Is installed in the body 119, the lower sprocket 111 is supported by both bodies (not shown) at the lower rear end of the bar screen (103). The driving means 115 is controlled by the control panel 121, the debris 101 removed by the weight wiper 117 is discharged to the debris discharge container 123.

Referring to FIG. 9, the rake 107 is disposed in a state in which the back plate 108 is inclined at an angle with respect to the horizontal direction of the rake 107 to the rear, and side plates 106 having a rhombus shape are formed at both sides. Attached to the central portion of the side plate 106 is connected to the chain 110 is provided. As a result, when the rake 107 passes through the hinged bar space 105, the back plate 108 pushes out the hinged bar space 105, and the rake 107 is the weighted wiper 117. The upper edge 106a of the side plate 106 guides the movement of the weighted wiper 117 as it passes.

The hinged bar space 105 is rotated by a predetermined angle in the direction of the arrow when the rake 107 passes in the state of supporting the bar screen 103, and after the rake 107 passes, to its original position by its own weight It is fed back to support the bar screen 103.

When the rake 107 is raised, the weighted wiper 117 first reaches the end of the back plate 108 of the rake 107 as shown in FIG. 10, and when the rake 107 is further raised, Due to the weight of the wiper 117, the contaminants 101 in the rake 107 are discharged to the contaminant discharge container 117.

The upper and lower sprockets 109 and 111 have the same diameter.

The control panel 121 may automatically or manually control the operation of the driving device 115, a method based on the level difference between the front and rear ends of the bar screen 103, an operation method by a timer (TIMER), and the like. The two can be controlled by a combined operation, and the level switch LEVEL SWITCH can be installed only at the front end of the bar screen 103 to control the operation by the water level.

The configuration and operation of the drive device 115 are the same as the configuration and operation of the drive device according to the first embodiment.

The operation of the contaminant removing device according to the second embodiment of the present invention configured as described above will be described with reference to FIGS. 11A to 11E.

When the driving device 115 is operated by the control of the control panel 121, the upper sprocket 109 rotates clockwise, and the chain 113 circulates the upper sprocket 109 and the lower sprocket 111. By this, the rake 107 is moved along the path of the chain 113.

The rake 107 rotates and descends as shown in FIG. 11B in a stationary state (operation standby state) waiting for the next removal operation after discharging the contaminants as shown in FIG. 11A, and the rake 107 is lowered as shown in FIG. 11C. 111) Rotates and snaps to the clearance between the bar screens. Thereafter, as shown in FIG. 11D, the rake 107 moves up from the bottom to the top along the bar screen 103 while pulling up the contaminants 101 hanging on the bar screen 103, and the rake 107 as shown in FIG. 11E. Before reaching the upper sprocket 109, the wiper 117 removes the contaminants 101 contained in the rake 107, and is then placed in the stopped state (operation standby state) again as shown in Fig. 11A.

12 and 13, in the apparatus for removing a contaminant according to the third embodiment of the present invention illustrated in FIGS. 12 and 13, elements mounted on both left and right sides of the channel are symmetrical with each other. Therefore, only the elements of either end with respect to the rake will be described.

In the contaminant removing device according to the third embodiment of the present invention, the bottom of the bar of the screen 153 for filtering the contaminants 151 contained in the influent in the water treatment plant is inclined by a β angle of about 15 ° from the vertical. 152, the upper portion of the bar screen 153 is supported by the hinged bar-space 155 in the middle portion. A rake 157 that lifts up the contaminant 151 caught in the bar screen 153 is disposed downstream of the bar screen 153 to penetrate the clearance between the bar screen 153, and A rake 157 is mounted to the chain 163 circulating the upper sprocket 159 and the lower sprocket 161. The upper sprocket 159 is driven by the drive unit 165, and a wiper 167 for removing the contaminants 151 filtered by the rake 157 is supported by the body 169 after the upper sprocket 159. The upper sprocket 159 is installed in the body 169, and the lower sprocket 161 is supported by both bodies attached to the side wall 164 of the channel at the bottom of the rear end of the bar screen 153. The driving means 165 is controlled by the control panel 171, the debris 151 removed by the wiper 167 is discharged to the debris discharge container 173.

The hinged bar space 155 supports a load added to the bar screen 153 by the flow velocity, the head difference, and the like, when the rake 157 moves up to filter the contaminants 151 caught in the bar screen 153. It can be rotated by a predetermined angle in the direction to secure the movement path of the rake 157, and after the rake 157 passes through, return to its original position by its own weight to support the bar screen 153.

The wiper 167 contacts the wiper 167 while the rake 157 passes through the upper sprocket 159 and the return guide track 175 by the chain 163 to rake the contaminant 151 without impact. It has a shock-absorbing structure (not shown) so that it can be dropped from 157 and returned to its original position again.

The upper sprocket 159 has a larger diameter than the lower sprocket 161, and the chain 163 passing through the upper sprocket 159 circulates to the lower sprocket 161 along the return guide track 175.

The control panel 171 may control the operation of the driving device 165 automatically or manually, the method by the level difference between the front and rear end of the bar screen 153, the operation method by the timer (TIMER) during the automatic operation The two can be controlled by the combined operation, and the level switch LEVEL SWITCH can be installed only at the front end of the bar screen 153 to control the operation by the water level.

The operation of the contaminant removing device according to the third embodiment of the present invention configured as described above will be described with reference to FIGS. 14A to 14E.

When the driving device 165 is operated by the control of the control panel 171, the upper sprocket 159 rotates clockwise, and the chain 163 circulates the upper sprocket 159 and the lower sprocket 161. By this, the rake 157 is moved along the path of the chain 163.

The rake 157 descends as shown in FIG. 14B in a stopped state (operation standby state) waiting for the next removal operation after discharging the contaminants as shown in FIG. 14A, and the rake 157 is lower sprocket 161 as shown in FIG. 14C. Rotate the knob to fit the clearance between the bar screens. Thereafter, as shown in FIG. 14D, the rake 157 moves upward from the bottom along the bar screen 153 to pull up the contaminants 151 hanging on the bar screen 153, and the rake 157 as shown in FIG. 14E. While rotating the upper sprocket 159, the contaminant 151 contained in the rake 157 is discharged to the contaminant discharge container 173, and the wiper 167 before passing the return guide track 175 while the rake 157 continues to move. ), The nip 151 is completely discharged by the wiper 175 while the rake 157 passes through the return guide track 175 in contact with. Thereafter, as shown in Fig. 14A, it is placed in the stop state (operation standby state) again.

As described above, the apparatus for removing a contaminant according to the present invention has a semicircular upper shape of the bar screen as in the first embodiment, and thus, when the rake rotates the upper bar screen, the contaminants can be removed from the rake without a separate wiper. Rake and sprockets to remove the, drive, body, etc. are all located at the rear end of the bar screen is not affected by any contaminants, and does not interfere with the fluid flow at all. In addition, the bar screen is fixed only at the bottom of the channel and its upper part has no or no intermediate support, so the fluid flows smoothly, and the claws are caught from the bottom to the top while the rake protrudes from the rear end to the front end. As it moves up and up, it is possible to completely remove the impurities on the bar screen in one cycle.

Embodiments of the contaminant removing device according to the present invention described above are for explaining the spirit of the present invention, the present invention is not limited to the embodiment described above. Those skilled in the art will be able to modify the apparatus for removing contaminants in accordance with the present invention without departing from the scope of the appended claims.

Claims (11)

delete The upper sprocket 65 is mounted on the shaft of the drive unit 71, and below the lower sprocket 67, which is interconnected by the chain 51, a plurality of rakes 45 are arranged on the chain 51. In the debris removal device in which the rake 45 pulls up the debris at the front end of the bar screen 43 by driving the drive device, A main guide track 57 disposed obliquely at the rear end of the bar screen 43 and having two front and rear straight portions and two upper and lower curved portions; An auxiliary guide track 59 having two front and rear straight portions and two upper and lower curved portions; A main guide roller 47 coupled to the chain 51 and moving along the main guide track 57; It is connected to the main guide roller (47) by a guide link (55), characterized in that it comprises an auxiliary guide roller (53) moving along the auxiliary guide track (59). delete The apparatus of claim 2, wherein the upper and lower ends of the auxiliary guide tracks (59) are lower than the upper and lower ends of the main guide tracks (57). delete delete delete delete delete delete delete