JP7483199B2 - Cake peeling device and cake peeling method for filter press - Google Patents

Description

The present invention relates to an improvement to a filter press that separates cake by running a filter cloth suspended between filter plates, and more specifically to a cake separation device and cake separation method that forcibly removes cake that has not been properly separated.

Traditionally, filter presses separate the raw liquid into solids and liquids in a filtration chamber equipped with a pair of filter cloths, then open the filter plates that form the filtration chamber to allow the cake remaining inside to fall and be discharged.

Patent Document 1 discloses a filter press in which the upper end of the filter cloth is suspended by a spring and the lower edge is attached to the lower end of the filter plate. When the filter plate is opened, cake is discharged below through a large opening, and cake that has adhered to the filter cloth and is poorly peeled is allowed to hang downward and detected with a laser beam.

There is also a filter press in which a filter cloth suspended between filter plates is run downward and the filter cloth is turned over to peel off the cake. Patent Document 2 discloses a filter cloth running type filter press in which a pair of filter cloths is arranged between the filter plates, the upper ends of the filter cloths are connected to a drive chain, and the lower ends of the filter cloths on the front and rear of the filter plates are wrapped around a return roll and connected to the other end of the drive chain.

Japanese Utility Model Application Publication No. 61-191106 Patent No. 3815433

In the filter press of Patent Document 1, the filter cloth is clamped to the front and rear filter plates during filtration, and solid-liquid separation occurs due to the pressure of the raw liquid being injected, so when the plates are opened, the filter cloth is likely to adhere to one of the filter plates. In particular, filter cloths that have been treated to seal the periphery of the filter plate to prevent leakage from the filter cloth seal, or filter cloths that have a diaphragm on one side of the filter plate for squeezing and dewatering, tend to adhere to the filter plate frequently, and since they do not sag downward due to the weight of the cake, it is often difficult to detect poor cake peeling.

Even if the cake hangs down due to its own weight without adhering to the filter plate, only a small portion hangs down from the filter plate, and most of the cake that is attached to the filter cloth is between the filter plates. This makes it difficult to separate the part hanging down from the filter plate from the filter cloth by applying an impact to it, and to completely separate it, an operator had to manually pull it off from the side of the filter plate.

The filter press in Patent Document 2 peels off the cake from the filter cloth by running the filter cloth downward and inverting it with a return roll below the filter plate. Because the return roll inverts the filter cloth up to below the raw liquid supply plate that is attached to the filter cloth, the cake is peeled off from the filter cloth, but sometimes part of the cake adheres to the raw liquid supply plate and hangs down, preventing it from being completely peeled off. If the filter press is moved to the next process in this state, it can cause problems such as the supply of raw liquid to the filtration chamber and solid-liquid separation, and the operation of the filter press may have to be stopped.

The present invention provides a filter press cake peeling device and a cake peeling method that automatically and mechanically peels cake that is not properly peeled when the plates are opened in a filter cloth traveling type filter press.

The present invention is a filter press in which a pair of filter cloths, with their upper ends joined together and holding a raw liquid supply plate between filter plates arranged in parallel so as to be freely opened and closed, are arranged so that raw liquid is supplied from the raw liquid supply plate to perform solid-liquid separation, and then the filter cloths are lowered while a pair of return rolls installed below invert the filter cloth to peel off the cake. The filter press is equipped with a peeling device that moves back and forth between the front and rear frames to bring a peeling bar into contact with the cake hanging from the raw liquid supply plate, and by bringing the peeling bar into contact with cake that has not been properly peeled, the cake is forcibly peeled off from the raw liquid supply plate by the impact.

The peeling device has a cover that spans from the front frame to the rear frame and a base that can move freely on the cover, and the base can be configured as a self-propelled type that is equipped with a drive machine, drive wheels connected to the drive machine, and a peeling bar that protrudes from the base.

In this method, a pair of filter cloths with their upper ends joined together and a raw liquid supply plate sandwiched between them are arranged in parallel and can be opened and closed freely. Raw liquid is supplied from the raw liquid supply plate to perform solid-liquid separation, and then the filter cloths are lowered and reversed by a pair of return rolls installed below to peel off the cake. If a detector detects a cake peeling failure below the row of filter plates, the peeling device is moved back and forth between the front and rear frames to bring the cake hanging from the raw liquid supply plate into contact with the peeling bar. The peeling device is only driven when a cake peeling failure is detected, thereby reducing the miscellaneous time.

The present invention is a method for reliably peeling poorly peeled cake in a filter cloth traveling type filter press by colliding a peeling bar with the cake. As a result, the risk of operational errors in the next process and subsequent steps is reduced, enabling stable dehydration operation of the filter press. In addition, by detecting poor peeling and activating the peeling device, miscellaneous time can be reduced.

FIG. 1 is a schematic side view of a filter press according to the present invention. FIG. 11 is a front view of a filter plate assembly for suspending the filter cloth. FIG. 2 is a perspective view of a pair of filter cloths suspended between filter plates. FIG. 2 is a side view of a main portion of a filter press in which a pair of filter cloths are suspended between filter plates. FIG. FIG. FIG. 11A and 11B are a schematic side view and a schematic plan view of a peeling device according to another embodiment of the present invention. FIG. 1 is an explanatory diagram of a detection device according to the present invention. FIG. 13 is a schematic diagram of the filter plate row immediately after the plates are opened. FIG. 13 is a schematic diagram of the filter plate rows when the cake is discharged. FIG. 13 is a schematic view of the filter plate array when the peeling device is operated.

FIG. 1 is a schematic side view of a filter press used in the present invention.
The filter press 1 has a number of filter plates 5... arranged in parallel on a pair of guide rails 4, 4 spanning a front frame 2 and a rear frame 3, and an opening/closing device 6 for opening and closing the filter plates 5... is supported on the rear frame 3.

Between the front frame 2 and the rear frame 3, a detection device 50 and a peeling device 55 are provided below the row of filter plates 5, each connected to a control device 54.

Figure 2 is a front view of the filter plate assembly that suspends the filter cloth. The filter plate arms 7, 7 of the filter plate 5 are supported on a pair of guide rails 4, 4 that are bridged between the front frame 2 and the rear frame 3. The filter cloth drive shaft 9 is supported on upper brackets 8, 8 that are erected on the top of the filter plate 5, and drive wheels 10, 10 are fitted to both ends of the filter cloth drive shaft 9. In this embodiment, the drive wheel 10 uses a sprocket with a gear on the outer periphery, and a drive chain 26 is wrapped around it. The filter cloth drive shaft 9 is interlocked and connected to a slide shaft 11 that is arranged along the top of the parallel filter plates 5 and transmits the driving force. A pair of return rolls 13, 13 are supported on lower brackets 12, 12 that hang down at the bottom of both ends of the filter plate 5. A filter bed 5a is formed in the center of the filter plate 5, and a raw liquid supply port 15 is opened in the upper center and a filtrate discharge port 16 is opened at both lower ends.

Figure 3 is a perspective view of a pair of filter cloths suspended between filter plates. The filter cloth 17 suspended between the filter plates 5, 5 has a bag portion 18, etc., which is formed by bonding the upper edges of the pair of filter cloths 17, 17 together, and an upper filter cloth core metal 19 is inserted through it. Bag portions 20, 20 are also formed on the lower edges of the filter cloths 17, 17, and lower filter cloth core metals 21, 21 are inserted through them. A raw liquid supply plate 22 is sandwiched between the pair of filter cloths 17, 17, and the raw liquid passage 24 of the raw liquid supply plate 22 is bonded to a through hole 23 opening in the upper center of the filter cloth 17, and a liquid supply path 25 is provided that branches off from the raw liquid passage 24 of the raw liquid supply plate 22 and supplies raw liquid to the filtration surface of the filter cloth 17.

Figure 4 is a side view of the main part of a filter press in which a pair of filter cloths are suspended between filter plates, with a filter cloth drive shaft 9 supported by upper brackets 8, 8 erected on the top of the filter plate 5, and a slide shaft 11 for transmitting the driving force shown in Figure 2 is interlockingly connected to this filter cloth drive shaft 9. A pair of filter cloths 17, 17 are arranged between the parallel filter plates 5, 5..., and a drive chain 26 is connected to both ends of an upper filter cloth core metal 19 that suspends the pair of filter cloths 17, 17, and each is hung around a drive wheel 10, 10 fitted to the filter cloth drive shaft 9 at the top of the filter plate 5. The lower ends of the filter cloths 17, 17 suspended at the front and rear of the filter plate 5 are respectively hung around a pair of return rolls 13, 13 arranged below the filter plate 5, and both ends of a lower filter cloth core metal 21, 21 inserted into the lower end of the filter cloth 17 are connected to the other end of the drive chain 26, 26, to suspend the filter cloths 17... The driving force is transmitted from the slide shaft 11 shown in Figure 2 to the filter cloth drive shaft 9, causing the filter cloth 17 to rise and fall in a seesaw-like manner.

When the parallel filter plates 5 are closed, the raw liquid supply plate 22 suspended from the filter cloth 17 is sandwiched between the front and rear filter plates 5, 5, forming a filtration chamber 27 between the pair of filter cloths 17, 17 stretched across the filtration bed 5a of the filter plate 5. The raw liquid supply port 15 formed on the filter plates 5, 5 is connected to the raw liquid passage 24 of the raw liquid supply plate 22, and the raw liquid is pressure-fed into the filtration chamber 27 from the liquid supply passage 25 of the raw liquid supply plate 22, and solid-liquid separation is performed on the filtration surface of the filter cloth 17.

5 and 6 are a schematic side view and a schematic plan view of the peeling device.
The peeling device 55 of the present invention is configured so that a peeling bar 56 can move back and forth along the lower ends of the rows of filter plates 5. A pair of driving sprockets 57, 57 and driven sprockets 58, 58 are journalled on both sides of the front frame 2 and the rear frame 3, respectively, around which endless traction chains 59, 59 are looped. A stand 60 is connected to both ends of the traction chain 59, and the peeling bar 56 protrudes inward from the stand 60.

In this embodiment, a single peeling bar 56 is bridged between the opposing stands 60, 60 and supported at both ends, but the peeling bar 56 may be cantilevered from the stand 60, or each stand 60, 60 may be moved back and forth alternately. Also, the peeling device 55 may be made up of only one stand 60.

The opposing drive sprockets 57, 57 are connected by a connecting shaft 61 and rotate synchronously. The drive sprocket 57 is rotated by a driver 62, and the stand 60 and peeling bar 56 connected to a traction chain 59 are configured to be movable between the two frames 2, 3. The peeling bar 56 is made of an impact-resistant tube or the like, and moves parallel to the bottom of the filter plate 5, specifically directly below the raw liquid supply plate 22 that has been lowered to the lowest end.

If necessary, known speed reducing means such as gears may be used between the driver 62 and the drive sprocket 57.

The towing chain 59 is protected by a cover 63 shown in Figure 7, which is bridged from the front frame 2 to the rear frame 3. The cover 63 is configured in a roughly rectangular shape with upper and lower guides 64, 64 that support the towing chain 59 and the frame 60 in sliding contact, an outer plate 65, and an inner plate 66. The inner plate 66 is cut out in a predetermined section to allow the peeling bar 56 that protrudes inward from the frame 60 to move. The frame 60 may be equipped with rolling wheels or the like to reduce frictional resistance with the guide 64.

FIG. 8 is a schematic side view and a schematic plan view of a peeling device according to another embodiment.
The peeling device 55 of the second embodiment includes a pair of self-propelled platforms 70, 70 below the guide rails 4 and movable between the frames 2, 3.

The drive unit 71 is built into the base 70, and drive wheels 72 are connected to the drive unit 71 and axially supported on the base 70 so as to be freely rotatable. In this embodiment, a pinion 72 is used as the drive wheel 72, and by rotating the pinion 72 with the drive unit 71, the wheel travels while meshing with a rack 73 bridged between the two frames 2 and 3. In this embodiment, the rack 73 is provided on the lower guide 64 of the cover 63, thereby simultaneously providing safety measures for the peeling device 55. The base 70 may also be equipped with auxiliary wheels to control the position while traveling, if necessary.

The self-propelled peeling device 55 may be one in which a power source such as a drive unit 71 is built into the stand 70, and the pinion 72 may be replaced with wheels, or the drive unit 71 may be replaced with a cylinder with the cylinder rod fixed to one of the frames.

Furthermore, to improve the peeling effect when it comes into contact with the cake, it may be made rotatable and the peripheral surface of the peeling bar 56 may be uneven so that it rotates in the direction of pushing down the cake. The peripheral unevenness may be cutter-shaped with a sharp tip, or a spiral worm gear-shaped, etc., and may be selected as appropriate depending on the properties and thickness of the cake. The power source for rotating the peeling bar 56 may be connected to a drive wheel 72 journaled on the stand 70, or a small drive unit may be separately installed.

FIG. 9 is an explanatory diagram of the detection device.
The detection device 50 of the present invention is composed of a transmission type photoelectric sensor. A light projector 51 is disposed on the rear frame 3 of the filter press 1, and a light receiver 53 for receiving a light beam 52 emitted from the light projector 51 is disposed on the front frame 2. The light beam 52 is emitted in parallel along the lower ends of the rows of 5 filter plates and is received by the opposing light receiver 53. When the light beam 52 is blocked by poorly peeled cake and does not enter the light receiver 53, a peeling device 55 is operated by a control device 54.

In this embodiment, in order to detect the cake hanging down from the raw liquid supply plate 22 located at the center of the filter plate 5 when the cake is peeled off, a light projector 51 and a light receiver 53 are provided on each frame 2 and 3 so that a light beam 52 irradiates the area below the lowered raw liquid supply plate 22.

Note that the detection device 50 is not limited to the photoelectric sensor shown in this embodiment, and a remote detection device may be configured using a well-known sensor.

FIG. 10 is a schematic diagram of the filter plate rows immediately after the plates of the filter press are opened.
The cake obtained by solid-liquid separation in the filtration chamber 27 is continuously attached to the filter cloth 17 from the raw liquid supply plate 22 at the upper end of the filtration chamber 27 to the lower end of the filtration chamber 27. Immediately after the parallel filter plates 5 are opened, some of the cake peels off from the filter cloth 17 due to the cake's own weight or vibrations caused when the plates are opened, but most of the cake remains attached to the filter cloth 17 after the plates are opened.

FIG. 11 is a schematic diagram of the filter plate rows when the cake is discharged.
A driving force is transmitted from the slide shaft 11 to the filter cloth drive shaft 9, and the pair of filter cloths 17 are raised and lowered in a seesaw manner. The pair of filter cloths 17, on which solid-liquid separation has been performed below the raw liquid supply plate 22 and cake has adhered thereto, travel downward and are then reversed and raised by a pair of return rolls 13, 13 below the filter plates 5, 5. When the filter cloths 17 travel to the bottom end, the raw liquid supply plate 22 has descended to the vicinity of the return rolls 13, 13, and the filter cloths 17 spread out in a V-shape from the front and rear of the raw liquid supply plate 22 toward the return rolls 13, 13.

At this time, most of the cake peels off from the filter cloth 17 and falls downward, but some of the cake adheres to the raw liquid supply plate 22 and hangs down from the lower end of the raw liquid supply plate 22. This cake blocks the light beam 52 that is irradiated directly below the raw liquid supply plate 22 and does not enter the receiver 53. The controller 54 receives a signal from the receiver 53 and operates the peeling device 55.

FIG. 12 is a schematic diagram of the filter plate array when the peeling device is in operation.
After the detector 50 detects a cake peeling failure, the controller 54 operates the peeling device 55 to peel off the cake hanging down from the raw liquid supply plate 22 .

In this embodiment, a peeling device 55 that operates a stand 60 and a peeling bar 56 with a traction chain 59 will be described. Specifically, the driving machine 62 is operated to rotate the traction chain 59 between the frames 2 and 3, and the peeling bar 56 is brought into contact with the poorly peeled cake hanging down from the concentrate supply plate 22. The impact of the contact with the peeling bar 56 causes the cake hanging down from the lower end of the concentrate supply plate 22 to tilt around the adhesion part as a fulcrum, and it peels off and falls due to its own weight and stress concentration.

In this embodiment, the peeling bar 56 is always stored on the front frame 2 side, and the control device 54 operates the peeling bar 56 from the front frame 2 to the rear end of the row of filter plates 5 or near the rear frame 3, then stops it and returns it to the front frame 2 side. The position of the peeling bar 56 is controlled by known means such as controlling the operation time of the driver 62 or a contact/non-contact type position sensor. The reciprocating movement of the peeling bar 56 may be controlled by switching the forward and reverse rotation of the driver 62, or by switching the transmission means between the driver 62 and the drive sprocket 57.
The running speed of the peeling bar 56 is appropriately adjusted depending on the cake thickness, the properties of the raw liquid, etc.

In this embodiment, the peeling device 55 is operated only if poor cake peeling is detected after the filter cloth 17 has been moved, but the filter plate 5 may be opened to discharge the cake, and then the peeling device 55 may be moved back and forth below the filter plate 5 as a series of operations.

The filter press cake peeling device and cake peeling method of the present invention peels the cake from the filter cloth while lowering and inverting the filter cloth, and detects cake that has stuck to the raw liquid supply plate and has not been properly peeled off, allowing for reliable peeling. It can be applied to drinking water sludge, sewage sludge, industrial wastewater sludge, etc., using a filter press, and is particularly effective for raw liquids that contain organic matter that tends to stick to resin or metal raw liquid supply plates.

Reference Signs List 1 Filter press 2 Front frame 3 Rear frame 5 Filter plate 13 Return roll 17 Filter cloth 22 Raw liquid supply plate 50 Detection device 55 Peeling device 56 Peeling bar 57 Driving sprocket 58 Driven sprocket 59 Traction chain 60, 70 Frame 62, 71 Driving machine 63 Cover 72 Driving wheel

Claims (3)

A pair of filter cloths (17, 17) having upper ends joined together and sandwiching a raw liquid supply plate (22) are disposed between filter plates (5) arranged in parallel so as to be freely opened and closed, raw liquid is supplied from the raw liquid supply plate (22) to perform solid-liquid separation, and then the filter cloth (17) is lowered while being inverted by a pair of return rolls (13, 13) provided below to peel off a cake,
A cake peeling device for a filter press, comprising a peeling device (55) that reciprocates between front and rear frames (2, 3) to bring a cake hanging down from a raw liquid supply plate (22) into contact with a peeling bar (56). The peeling device (55) is
A cover (63) that bridges from the front frame (2) to the rear frame (3);
A stand (70) that is movable on the cover (63),
The stand (70) has:
A driving machine (71);
A drive wheel (72) connected to a drive machine (71);
A peeling bar (56) protruding from the stand (60);
The cake peeling device of a filter press according to claim 1, further comprising: A pair of filter cloths (17, 17) having upper ends joined together and sandwiching a raw liquid supply plate (22) are disposed between filter plates (5) arranged in parallel so as to be freely opened and closed, raw liquid is supplied from the raw liquid supply plate (22) to perform solid-liquid separation, and then the filter cloth (17) is lowered while being inverted by a pair of return rolls (13, 13) provided below to peel off a cake,
When the detector (50) detects a cake peeling failure below the filter plate (5) row,
A method for peeling cake from a filter press, comprising the steps of: reciprocating a peeling device (55) between front and rear frames (2, 3) to bring cake hanging down from a stock liquid supply plate (22) into contact with a peeling bar (56).

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