JP2019209257A - Filter press - Google Patents

Abstract

To provide a filter press that can make a filtering process more efficient and reduce costs.SOLUTION: The filter press is configured to repeatedly execute a treatment liquid pressing-in step for press water to be treated into a filtering chamber formed in a frame of a filtering frame in a closed plate state where the filtering frame is held through a filtering sheet by a pair of filtering plates and a back-washing treatment step for supplying back-washing air into each filtering plate outside the filtering sheet, which can drop sludge adhering to an inner surface of the filtering sheet by the back-washing treatment step and therefore can perform filtering continuously, so that the filtering step can be made more efficient and costs can be reduced.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a filter press that forms a filter chamber by sandwiching a filter frame and a filter sheet between a pair of opposing filter plates.

  2. Description of the Related Art Filter presses that perform filtration by pressing a liquid to be processed into a filter chamber formed between stacked filter plates have been known for a long time. As such a filter press, for example, Patent Document 1 proposes a duplex type in which a filter frame is sandwiched between a filter plate and the inside of the filter frame is a filter chamber. In this duplex type configuration, a filter chamber is formed in the filter frame by the filter sheets positioned on both sides of the filter frame with the filter frame held between the filter plates. Then, the liquid to be treated is press-fitted into the filter chamber, whereby the filtrate filtered by the filter sheet is discharged to the outside of the filter chamber.

Japanese Patent Laid-Open No. 61-149213 FIG.

  In the conventional filter press described above, as the time for performing filtration by press-fitting the liquid to be treated becomes longer, the amount of the liquid to be treated to flow into the filter chamber decreases due to clogging of the filter sheet, and the efficiency of filtration decreases. . For this reason, when the filtration efficiency is lowered, it is necessary to release the state where the filter frame is sandwiched by the filter plate, open the filter chamber, take out the cake accumulated in the filter chamber, and replace the filter sheet. It was. As described above, in the filter press of the conventional configuration, every time the filtration capacity is reduced due to clogging of the filtration sheet, the filtration must be stopped and the filtration sheet must be exchanged, and the exchange frequency of the filtration sheet is relatively high. . In response to such a current situation, it has been required to reduce the frequency of replacement of the filter sheet to improve the efficiency of the filtration process and to reduce the cost of the filtration process.

  The present invention proposes a filter press capable of realizing an efficient filtration process and cost reduction.

  The present invention is arranged between a pair of filter plates and a pair of filter plates which are arranged so as to be able to move away from each other and each have a groove portion communicating with a discharge passage for discharging filtrate on opposite surfaces. A filter frame sandwiched between plates, and interposed between both filter plates and the filter frame, and located on both sides of the filter frame in a closed plate state with the filter frames sandwiched by both filter plates. And a processing liquid press-fitting means for press-fitting the processing liquid into the filtering chamber formed in the closed plate state, and the processing liquid press-fitted into the filtering chamber is filtered. In the filter press for filtering and discharging the filtrate to the discharge path through the groove portion of the filter plate, the filter press has backwash air supply means for supplying backwash air into the groove portion of the filter plate in the closed plate state. In the closed plate state, the processing liquid press-fitting means is operated and controlled, and the liquid to be processed is filtered into the filter chamber. And after stopping the press-fitting of the liquid to be treated, the back-wash air supply means is operated and controlled so that the back-wash air is supplied into the groove located outside the filter chamber for a predetermined time. A filter press characterized by comprising a filtration process control means for repeatedly executing and controlling the backwashing process to be supplied until a predetermined filtration termination condition is satisfied.

  The inventors of the present invention diligently studied about the reduction of the filtration capacity in the above-described conventional configuration, and came to invent the configuration of the present invention. In other words, the clogging of the filter sheet caused by filtration is caused by adhering substances (hereinafter referred to as sludge) contained in the liquid to be treated on the inner surface of the filter sheet, and this adhered sludge is filtered. If it can be dropped from the sheet, the reduction in filtration capacity can be improved. Therefore, various methods for removing the sludge adhering to the inner surface of the filter sheet have been studied, and the configuration of the present invention has been achieved.

  In such a configuration of the present invention, sludge adhering to the inner surface of the filter sheet in the treatment liquid press-fitting process is dropped from the filter sheet by supplying backwash air from the outside of the filter sheet in the backwash process process. Can do. Thereby, since the filtration capability of the filter sheet which fell by adhesion of sludge can be improved, it can filter with a desired filtration capability in the process liquid press-fit process performed again after a backwash process process. Therefore, according to this configuration, since the filtration by the treatment liquid press-fitting step can be continuously performed a plurality of times, the frequency of opening the filter plate and replacing the filter sheet can be reduced, and the efficiency of the filtering work can be dramatically improved. Can be improved. And since the frequency | count of replacement | exchange of a filter sheet can also be reduced, the cost concerning a filter sheet can be reduced.

  In addition, the sludge which fell from the inner surface of the filter sheet accumulates in a filter chamber by repeating a process liquid injection process and a backwash process process. And as the frequency | count of performing a series of processes from a process liquid injection process to a backwash process process increases, the filtration capability of a filter sheet falls with the sludge collected in the filter chamber. Therefore, when a predetermined filtration end condition is satisfied, it is preferable to open the filter plate to remove sludge (cake that is a lump of sludge) accumulated in the filter chamber, and further to replace the filter sheet. Here, the filtration termination condition is preferably a condition determined based on the filtration capability of the filtration sheet.

  In the filter press of the present invention described above, the filter chamber formed in a closed plate state in which the filter frame is sandwiched between the two filter plates is provided with a drainage air supply means for supplying the drainage air, and the filtration process control means includes: In addition, when the processing liquid press-fitting means stops the press-fitting of the liquid to be processed between the processing liquid press-fitting step and the backwashing processing step, the operation of controlling the drainage air supply means is performed so that the liquid is discharged into the filter chamber. A configuration is proposed in which the supplied liquid removal treatment step is executed. In this configuration, the backwashing process is performed with the stop of the supply of the dewatered air by the dewatered air supply means.

  In such a configuration, the treatment liquid press-fitting step, the liquid removal treatment step, and the backwash treatment step are executed in order, and a series of steps from the treatment liquid press-fitting step to the backwash treatment step is completed for predetermined filtration. Repeat until the condition is met. In this configuration, the liquid to be treated remaining in the filter chamber can be filtered after the treatment liquid press-fitting means stops the press-fitting of the liquid to be treated by the liquid removal treatment process performed after the treatment liquid press-fitting process. Here, if the backwash process is performed after the process liquid press-in process without performing the liquid removal process, the liquid to be processed remaining in the filter chamber after the process liquid press-in process may flow back due to the backwash air. is there. On the other hand, in this structure, since the to-be-processed liquid in a filter chamber can be filtered by a liquid removal process as mentioned above, it can prevent that this to-be-processed liquid flows back in a backwash process. Moreover, the liquid component of the sludge remaining in the filter chamber can be filtered through the filter sheet by executing the liquid removal treatment step. Therefore, there is an advantage that it is easy to remove sludge adhered to the filter sheet in the backwash process.

  In the above-described filter press of the present invention, the filtration end condition of the filtration process control means is that the inflow amount per unit time of the liquid to be treated that is press-fitted into the filter chamber is a predetermined threshold value or less in the treatment liquid press-fitting process. A configuration is proposed.

In such a configuration, the filtration end condition is a condition based on the filtration ability that is reduced by the sludge (cake) accumulated in the filter chamber, and sludge that has fallen from the filter sheet by the backwash treatment process accumulates in the filter chamber. Shows a situation where the desired filtration capacity cannot be exhibited. That is, the filtration termination condition of this configuration does not indicate a situation where the filtration capacity can be recovered by the backwashing process, but indicates a situation where the desired filtration capacity cannot be recovered even by the backwashing process, In other words, it indicates the timing of removal of sludge (cake) accumulated in the filter chamber and replacement of the filter sheet.
According to this configuration, removal of sludge (cake) accumulated in the filter chamber and replacement of the filter sheet can be performed at an appropriate timing when the filtration end condition is satisfied. Then, after that, the filter plate is again closed, and a series of steps from the treatment liquid press-fitting step to the backwash treatment step is repeated, whereby filtration with a desired filtration ability can be performed.

  In this configuration, when the filtration end condition is satisfied in the treatment liquid press-fitting step, the treatment liquid press-fitting step is finished, the liquid removal treatment step is executed, and the filter plate is attached along with the completion of the liquid removal treatment step. A configuration in which the sludge (cake) is removed, the filter sheet is exchanged, or the like is opened.

  In the above-described filter press of the present invention, the filter frame is suspended from the upper edge portion constituting the upper edge of the filter chamber in the closed plate state and from both ends of the upper edge portion, respectively, and is filtered in the closed plate state. Each of which has a side edge portion that forms a frame shape that opens downward between the side edge portions, and at least a lower portion of each side edge portion is formed in a tapered shape with a lower end as a blade edge shape. In the closed plate state, the filter plate is provided with a bottom edge portion that is pressed against each other via the filter sheet to form the bottom edge of the filter chamber. .

  In such a configuration, since the filter frame is opened downward between both side edge portions, the filter chamber formed in the frame of the filter frame has its bottom edge formed by pressure contact of both filter plates. The Therefore, in this configuration, when the filter plate is released from the closed plate state and separated from the filter frame, the bottom of the filter chamber (inside the filter frame) is opened, and sludge (cake) accumulated in the filter chamber is removed. It falls by its own weight from the filter chamber. Therefore, according to this structure, the function and operation | work for taking out the sludge (cake) collected in the filter chamber are not required, and this sludge (cake) can be easily discharged | emitted from a filter chamber by opening | releasing both filter plates.

  Furthermore, in this configuration, the filter sheet is sandwiched between the filter plate and the filter frame by the upper edge and both side edges of the filter chamber, and is sandwiched between the filter plates at the bottom edge of the filter chamber. Since both sides of the filter frame are formed in a tapered shape with the lower end of the lower edge of the filter frame, the filter sheet can be sandwiched without being largely bent at the lower end of the filter frame. Thereby, in this structure, the filter sheet of comparatively low intensity | strength can be used and the cost required for filtration can be reduced generally.

  According to the filter press of the present invention, sludge adhering to the inner surface of the filtration sheet by filtration can be removed by the backwash treatment process, and the reduction of filtration ability due to clogging of the filtration sheet can be recovered, so that the treatment liquid press-fitting process Can be continuously performed a plurality of times. Therefore, it is possible to reduce the frequency of opening the filter plate and replacing the filter sheet, and it is possible to improve the efficiency of the filtering operation and reduce the cost.

It is a side view of the filter press 1 of an open plate state. It is a side view of the filter press 1 of a closed plate state. It is a top view which shows the filter press main body 3 and the opening / closing mechanism 4 in an open plate state. (A) An enlarged side view of the filter press main body 3 in the open plate state, and (B) An enlarged side view of the filter press main body 3 in the closed plate state. 1 is a perspective view of a filter frame 10. FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 3 is a perspective view of the front side of the filter plate 11. FIG. It is (A) top view, (B) front view, and (C) side view of the filter plate 11. It is explanatory drawing which shows arrangement | positioning of the filter frame 10, the filter plate 11, and the filter paper S in a closed plate state. (A) The LL sectional view taken on the line in FIG. 9, (B) The MM sectional view taken on the line in FIG. 2 is a block diagram showing a control circuit of the filter press 1. FIG. It is a flowchart which shows a filtration process control process. It is a graph which shows the measurement result of filtration by filter press 1.

Embodiments according to the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the filter press 1 according to the present embodiment includes a base 2 placed on a floor or a work table, a filter press main body 3, and the filter press 1 in an open plate state and a closed plate state. An opening / closing mechanism 4 that converts and drives the filter press, a filter paper supply device 5 that supplies the filter paper S to the filter press main body 3, a supply pipe 7 that supplies a liquid to be treated and dewatered air to the filter press main body 3, respectively, and a filter press main body 3, a discharge pipe 8 for discharging filtrate and drained air, a cake collection unit 6 for collecting cake (sludge) discharged from the filter press main body 3, and a control device 50 for controlling the operation of the filter press 1 (FIG. 11). Reference). The filter press 1 of the present embodiment is a fully automatic type, and the control device 50 controls each device in an integrated manner to automatically execute the filtration step. In addition, the filter press 1 of a present Example is used suitably for the use etc. which filter and collect | recover cutting waste from the waste liquid (processed liquid) containing the cutting waste (sludge) which generate | occur | produces by metal processing.

  The filter press main body 3 includes a filter frame 10, a pair of filter plates 11 and 11 that sandwich the filter frame 10 from both sides, and end plates 12 a and 12 b that hold the filter plates 11 and 11. One end plate 12 a is fixed to the base 2, and the other end plate 12 b is connected to the opening / closing mechanism 4. By moving the other end plate 12 b forward and backward by the opening / closing mechanism 4, The filter plates 11 and 11 can be moved away from each other. Further, as shown in FIG. 4, the filter press main body 3 holds a plurality of large-diameter guide shafts 13a and small-diameter guide shafts 13b that penetrate the filter frame 10 and the filter plates 11 and 11 in the thickness direction. The filter plate 10 is held between the filter plates 11 and 11 by the guide shafts 13a and 13b. A compression coil spring 14 that urges the filter frame 10 in a direction away from the surface of the filter plate 11 is externally fitted to the narrow guide shaft 13b. The filter frame 10 is biased by the compression coil spring 14 so as to be separated from the filter plates 11 and 11 on both sides, and as shown in FIGS. 1 and 4A, the two filter plates 11 are opened. Held in an intermediate position.

  As shown in FIGS. 1 to 3, the opening / closing mechanism 4 includes a metal frame 4 a fixed on the base 2 and a hydraulic cylinder 4 b attached to the frame 4 a. An end plate 12b on one side of the filter press body 3 is connected to the piston rod 4c of the hydraulic cylinder 4b. In the contracted state of the hydraulic cylinder 4b, as shown in FIG. 1 and FIG. 4A, the two filter plates 11, 11 and the filter frame 10 are separated from each other, and the hydraulic cylinder 4b is extended. Then, as shown in FIG. 2 and FIG. 4 (B), the two filter plates 11 and 11 approach each other along the guide shafts 13a and 13b, and both the filter plates 11 and 11 pass through the filter paper S. In this state, the filter frame 10 is sandwiched between the closed plates. In the closed plate state, the filter chamber 15 is formed in the filter frame 10 by the filter paper S located on both sides of the filter frame 10.

  As shown in FIGS. 1 and 2, the filter paper supply device 5 is disposed above the end plates 12a and 12b, and includes a supply roller 5a around which a long unused filter paper S is wound, and each end plate 12a. , 12b, a recovery roller 5b that winds up the used filter paper S, and a motor (not shown) that rotationally drives each of the rollers 5a, 5b. Here, the upper and lower supply rollers 5a and the collection roller 5b are paired, and the filter paper supply device 5 includes two pairs of the supply roller 5a and the collection roller 5b. In such a filter paper supply device 5, the control device 50 drives and controls the motor in an open plate state, so that unused filter paper S wound around the supply roller 5 a is stretched on the surface of each filter plate 11. The clogged filter paper S after filtration is wound around the collection roller 5b and collected.

The supply pipe 7 is for supplying the liquid to be processed and the air for liquid removal to the filter chamber 15. The supply pipe 7 includes a treatment liquid supply pipe 7a to which a high-pressure liquid to be treated is supplied from a liquid-to-be-treated supply apparatus (not shown), and a high-pressure liquid removal air (hereinafter, referred to as an air pump (not shown)). An air supply pipe 7b to which a liquid is discharged is joined to one common supply pipe 7c and communicated with the upper portion of the filter chamber 15. The treatment liquid supply pipe 7a and the air supply pipe 7b are provided with electromagnetic valves 7d and 7e, respectively, and the electromagnetic valves 7d and 7e are individually controlled to be opened and closed by the control device 50 described above. That is, the control device 50 controls the opening / closing operation of the electromagnetic valves 7d and 7e, thereby supplying a high-pressure liquid to the filtration chamber 15 and supplying high-pressure degassed air to the filtration chamber 15. Thus, it is possible to switch to a state in which the supply of the liquid to be processed and the liquid to be removed to the filter chamber 15 is stopped.
In the present embodiment, a liquid meter 52 for detecting the storage amount of the liquid to be processed stored in the liquid supply apparatus to be processed is disposed. (See FIG. 11).

  Further, the supply pipe 7 is connected to a common supply pipe 7 c with an air vent pipe 17, and the air vent pipe 17 is provided with an electromagnetic valve 17 a. As will be described later, the electromagnetic valve 17a of the air vent pipe 17 is opened when the closed plate state is changed to the open plate state and when the backwash air is supplied. This opening makes it easy to convert to an open plate state, and backwash air can be discharged from the filter chamber 15.

  The discharge pipe 8 is for discharging the filtrate filtered by the filter paper S and the air for drainage that has passed through the filter paper S to a filtrate tank (not shown) outside the apparatus. An air supply pipe 9 for supplying back washing air is connected to the discharge pipe 8. Since the air supply pipe 9 is a main part of the present invention, the details will be described later.

  The cake collection unit 6 is a box that opens upward, and is disposed directly below the filter press body 3. This cake collection | recovery part 6 is provided so that the cake which fell from the filter chamber 15 may be accommodated, when converting from a closed plate state to an open plate state so that it may mention later.

  In the filter press 1 of this embodiment, the filter plates 11 and 11 are closed by the opening / closing mechanism 4 (FIGS. 2 and 4B), and the liquid to be treated is put into the filter chamber 15 in the closed plate state. The liquid to be treated is filtered by press-fitting. By this filtration, the filtrate is discharged through the discharge pipe 8, and the cake is accumulated in the filter chamber 15. Thereafter, when the filtration capacity of the filter paper S decreases, the supply of the liquid to be treated is stopped, and the dewatered air is pressed into the filter chamber 15 to promote the filtration of the machine to be treated remaining in the filter chamber 15. At the same time, the liquid component of the contaminants (sludge such as the cutting waste) remaining in the filter chamber 15 is discharged. Then, after supplying the dewatered air, a cake that is a lump of sludge remains in the filter chamber 15. When the filter plates 11 and 11 are converted from the closed plate state to the open plate state (FIGS. 1 and 4A) after the supply of the dewatered air, the cake falls due to its own weight and is recovered by the cake recovery unit 6. The In the case of further filtration, the filter paper supply device 5 rotates the supply roller 5a and the collection roller 5b to exchange the filter paper S disposed on the respective surfaces of the filter plates 11 and 11. And it filters by making it into a closed-plate state as mentioned above. In the configuration of this embodiment, the control device 50 automatically controls the opening / closing mechanism 4, the electromagnetic valves 7 d and 7 e, the filter paper supply device 5 and the like at a predetermined timing, triggered by the start operation by the operator. Filter. Since the operation control by the control device 50 relates to the main part of the present invention, the details will be described later.

Next, the main part of the present invention will be described.
The filter frame 10 described above is a frame plate manufactured by cutting a stainless steel plate. As shown in FIGS. 5 and 6, the filter frame 10 has a front and back symmetrical shape, and is a substantially inverted cover composed of an upper edge portion 20 and side edge portions 21 and 21 depending from both sides of the upper edge portion 20. It has a letter shape, and the inside of the frame surrounded by the upper edge 20 and the side edges 21 and 21 is opened downward. Both sides of the filter frame 10 are pressure receiving surfaces 23 and 23 sandwiched by the filter plates 11 and 11. In the closed plate state, both the filter plates 11 and 11 pass through the filter paper S to the pressure receiving surfaces 23 and 23, respectively. Each is pressed. In such a closed plate state, a gap closed by the filter papers S and S located on both sides of the filter frame 10 is formed in the frame of the filter frame 10 surrounded by the upper edge 20 and the side edges 21 and 21. Then, the filter chamber 15 is constituted by the gap in the frame (see FIG. 10A).

  Further, the upper edge portion 20 of the filter frame 10 is provided with a supply port 26 penetrating the upper edge portion 20 vertically in the center portion thereof. The above-mentioned common supply pipe 7c is connected to the upper opening of the supply port 26. In the closed plate state, the liquid to be processed and the dewatered air supplied from the common supply pipe 7c are supplied through the supply port 26. It flows into the filter chamber 15. Further, guide holes 27a and 27b penetrating the guide shafts 13a and 13b are provided in both side edges 21 and 21 of the filter frame 10 in the thickness direction.

  Such a filter frame 10 is formed so that its thickness is thinner toward the lower end. Specifically, the upper edge portion 20 is the thickest in the filter frame 10 and has a substantially uniform thickness. The side edge 21 includes a side upper part 21a that tapers downward from an upper end continuous with the upper edge part 20, a side central part 21b that maintains the thickness of the lower end of the side upper part 21a, and the side It is composed of a side lower portion 21c that tapers downward from the thickness of the central portion 21b and has a lower edge at the lower end. Thus, since the thickness of the side edge portions 21 of the filter frame 10 is tapered downward, the filter chamber 15 is formed in a space shape that becomes thinner downward.

  On the other hand, the pair of filter plates 11, 11 is a plate material made of polypropylene having a horizontally long rectangular shape, and has the same shape. The pair of filter plates 11, 11 are fixed to the end plates 12 a, 12 b on the back sides of the filter plates 11, 11, respectively, and are arranged on both sides of the filter frame 10 so as to face each other. As shown in FIGS. 7 and 8, the surface of the filter plate 11 has a substantially rectangular region at the center as a filter surface portion 30 that closes the inside of the filter frame 10 from one side. A substantially concave portion of the filter surface 30 is provided with a groove portion 34 in which grooves that are recessed in the thickness direction of the filter plate 11 are formed in a vertically striped lattice shape, and the filtrate or the like that has passed through the filter paper S in the closed plate state is provided in the groove portion 34. Flow down. Here, in the closed plate state, the outer peripheral edge of the groove portion 34 of the filter surface portion 30 is in close contact with the filter paper S, so that a closed gap 39 that closes the inside of the groove portion 34 is formed. In addition, a discharge port 36 that penetrates the filter plate 11 in the thickness direction is formed in the lower portion of the groove 34. A discharge pipe 8 is connected to the back side opening of the discharge port 36, and the filtrate or drainage air that has passed through the filter paper S in the closed plate state passes through the discharge port 36 from the closed gap 39 (groove 34), and then is discharged. 8 is discharged.

  The surface of the filter plate 11 has a substantially inverted U-shaped region composed of an upper region and a side region of the filter surface portion 30 as a clamping surface portion 31 that presses the pressure receiving surface 23 of the filter frame 10 through the filter paper S. Yes. Further, a horizontally long rectangular region below the filter surface portion 30 is used as a sealed surface portion 32 that is in pressure contact with the other filter plate 11 via the filter paper S. The clamping surface portion 31 has a shape that overlaps with the pressure receiving surface 23 of the filter frame 10 in a uniform manner, and the filter plate 11 is longer than the filter frame 10 by the amount of the sealing surface portion 32. Further, a packing 35 made of a rubber sheet is disposed on the filter plate 11 so as to cover the entire surface of the sandwiching surface portion 31 and the sealing surface portion 32 in order to improve the airtightness of the filter chamber 15. Further, the filter plate 11 is formed with guide holes 37a and 37b penetrating the guide shafts 13a and 13b on both side portions overlapping the guide holes 27a and 27b of the filter frame 10, respectively.

  On the surface of the filter plate 11, the sealing surface portion 32 that is in pressure contact with the other filter plate 11 without holding the filter frame 10 is most bulged. Further, the clamping surface portion 31 is formed thinner than the sealing surface portion 32 by the thickness of the filter frame 10 so as to be in close contact with the pressure receiving surface 23 of the filter frame 10. Here, since the lower portions 21c on both sides of the filter frame 10 have a tapered shape and the lower end thereof has a cutting edge shape, the filter paper S can be held almost without bending at the boundary between the sandwiching surface portion 31 and the sealing surface portion 32. . Further, the portion of the filter surface portion 30 where the groove portion 34 is not formed is formed so that the sandwiching surface portion 31 is flush with the horizontal width direction, so that the filter paper S can be held without being bent in the horizontal width direction. In addition, the back surface of the filter plate 11 fixed to the end plates 12a and 12b is a flat surface perpendicular to the separating direction.

The closed plate state by the filter frame 10 and the filter plates 11 and 11 will be described in further detail. In the closed plate state, as shown in FIGS. 9 and 10, the two filter plates 11 sandwich the filter frame 10 from both sides via the filter paper S, so that the filter chamber 15 is formed in the frame of the filter frame 10. It is formed. Specifically, the holding surface portion 31 of the two filter plates 11 is pressed against the pressure receiving surface 23 of the filter frame 10, and the inside of the filter frame 10 is closed by the filter papers S and S. A filter chamber 15 is formed in the frame. In this closed plate state, the clamping surface portion 31 is in pressure contact with the pressure receiving surface 23 and simultaneously the sealing surface portions 32 and 32 of the filter plates 11 and 11 are in pressure contact with each other, whereby the bottom edge of the filter chamber 15 is sealed. The Here, in the closed plate state, the filter paper S covers the inside of the filter frame 10 from both sides, contacts the inner side of the pressure receiving surface 23, covers the groove 34 of the filter surface portion 30 of the filter plate 11, and holds it. It abuts against the inner side of the surface portion 31 and the sealing surface portion 32. Therefore, the filter papers S and S located on both sides of the filter frame 10 are sandwiched between the pressure receiving surface 23 and the sandwiching surface portion 31 and between the opposed sealing surface portions 32 and 32, and the inside of the filter frame 10 is passed through the filter chamber. 15 and the inside of the groove 34 is a closed gap 39. In such a closed plate state, the outer peripheral edge of the filter chamber 15 is sealed through the filter papers S and S by the pressure contact between the filter frame 10 and the filter plate 11, so that the liquid to be treated is pressed into the filter chamber 15. Then, the liquid to be treated is filtered by the filter papers S and S. The filtered filtrate is discharged from the discharge pipes 8 and 8 through the closed gaps 39 and 39 outside the filter papers S and S (inside the grooves 34 and 34). The liquid removal air is the same as the liquid to be processed.
In addition, the code | symbol 40 in FIG. 9 is a screw hole for fixing the filter plate 11 to end plate 12a, 12b.

  Further, as shown in FIGS. 1 and 2, an air supply pipe 9 that supplies backwash air is connected to the discharge pipe 8 at a portion downstream from the discharge port 36 of the filter plate 11. An electromagnetic valve 8a is disposed on the downstream side of the connection portion of the discharge pipe 8 with the air supply pipe 9, and when the electromagnetic valve 8a is open, the groove 34 (closed gap 39) of the filter plate 11 is provided. ) Communicates with a filtrate tank (not shown) outside the machine via the discharge pipe 8. On the other hand, the air supply pipe 9 supplies high-pressure backwash air (hereinafter referred to as backwash air) from an air pump (not shown) outside the machine, and the solenoid valve 8a is closed when the solenoid valve 8a is closed. When 9 a is opened, backwash air is supplied to the groove 34 of the filter plate 11 through the upstream portion of the discharge pipe 8. The electromagnetic valves 8a and 9a are controlled to be opened and closed by the control device 50 (see FIG. 11).

Next, the filtration process controlled by the control device 50 will be described.
The filtration step includes a closing plate step for converting from the open plate state to the closed plate state by the operation of the opening / closing mechanism 4, a treatment liquid press-fitting step for press-fitting the liquid to be treated into the filter chamber 15, and supplying deliquid air to the filter chamber 15 By a dewatering process, a backwash process for supplying backwash air to the closed gaps 39, 39, an opening process for converting from a closed plate state to an open plate state by the operation of the opening / closing mechanism 4, and the operation of the filter paper supply device 5 A filter paper replacing step for replacing the filter paper S. The control device 50 executes these processes in a predetermined order by executing a filtration process control process described later.
That is, the control device 50 stores programs for operating the opening / closing mechanism 4, the filter paper supply device 5, and the electromagnetic valves 7d, 7e, 8a, 9a, and 17a, and controls the operation of each program at a predetermined timing. Thus, the filtration step is executed. The control device 50 includes a storage device ROM (not shown) that stores each program, a storage device RAM (not shown) that temporarily stores data related to each operation, and a CPU (not shown) that executes each program. )). In a present Example, the control apparatus 50 performs a series of filtration processes by performing a filtration process control process according to a program.

  As shown in FIG. 12, the filtration process control process by the control device is started upon the start operation (ON operation of the start switch) by the operator. When the start operation is performed, the closing plate operation process is executed. In the closing plate operation process, the hydraulic cylinder 4b of the opening / closing mechanism 4 is driven and controlled to convert the filter plates 11 and 11 in the open plate state from the open plate state to the closed plate state. As a result, the filter plates 11, 11 sandwich the filter frame 10 through the filter papers S, S to form the filter chamber 15 in the frame of the filter frame 10, and the grooves 34 of both the filter plates 11, 11. , 34 are formed with the closed gaps 39, 39 (see FIG. 10). Here, the filter chamber 15 and the closed gaps 39 and 39 are separated by filter papers S and S. Such a closed plate state is maintained until the filter plates 11 and 11 are converted to an open plate state by an opening plate operation process described later. The above-described closing plate process is executed by the closing plate operation process.

  In the closed plate state, the processing liquid press-fitting process is executed, and the electromagnetic valve 7d of the processing liquid supply pipe 7a is opened. As a result, a high-pressure liquid to be processed is press-fitted into the filter chamber 15 through the processing liquid supply pipe 7a and the common supply pipe 7c from the liquid supply apparatus outside the apparatus. Here, since the solenoid valve 7e of the air supply pipe 7b and the solenoid valve 17a of the air vent pipe 17 are held in a closed state, the liquid to be treated does not flow into the air pump side and the air vent pipe 17 side. Further, in the processing liquid press-fitting process, when the opening operation of the electromagnetic valve 7d is started, measurement of the inflow time for press-fitting the liquid to be processed is started. Further, in the processing liquid press-fitting process, the storage amount of the processing liquid in the processing liquid supply apparatus is periodically acquired (for example, every fixed time such as 1 second or 2 seconds) by the liquid meter 52, and unit time ( For example, the liquid amount (hereinafter referred to as inflow amount) of the liquid to be treated that is press-fitted into the filter chamber 15 per 30 seconds or 1 minute) is measured. The liquid level meter 52 of this embodiment measures the liquid level height of the liquid to be processed stored in the liquid supply apparatus to be processed, and the amount of fluctuation (the amount of decrease) of the liquid level of the liquid to be processed. ) To determine the amount of inflow. This is because the amount of decrease in the liquid level of the liquid to be treated stored and the amount of inflow are in a proportional relationship, and the amount of inflow can be known from the amount of decrease.

  In such a state that the liquid to be treated is being press-fitted, the liquid to be treated that has been press-fitted into the filter chamber 15 is filtered by the filter papers S and S on both sides, and the filtrate that has passed through the filter papers S and S is closed. It flows into 39. Then, the filtrate is discharged from the discharge pipe 8 through the closed gaps 39 and 39. In the discharge pipe 8, since the electromagnetic valve 8a is open and the electromagnetic valve 9a of the air supply pipe 9 is closed, the filtrate is discharged to a filtrate tank outside the machine.

During the press-fitting of the liquid to be processed, a process for determining whether or not the inflow amount per unit time (a decrease in the liquid level) is equal to or less than a predetermined threshold, and the inflow time of the liquid to be processed And a process for determining whether or not a predetermined continuous press-fitting time has elapsed. Then, when the inflow amount per unit time becomes equal to or less than the threshold value, or when the inflow time of the liquid to be processed has passed the continuous press-fitting time, the processing liquid stop process is executed, and the electromagnetic valve of the processing liquid supply pipe 7a 7d is closed. Thereby, supply of the to-be-processed liquid to the filter chamber 15 is stopped. The process liquid press-in process is from the process liquid press-in process to the process liquid stop process.
Here, the threshold value for determining the amount of inflow per unit time (the amount of decrease in the liquid level) is a value set for determining that the filtration capacity has decreased due to clogging of the filter paper S. In this embodiment, when the inflow amount is equal to or less than the threshold value, the threshold value is set as a value that does not sufficiently exhibit the desired filtration capacity even when backwash air described later is supplied. On the other hand, the continuous press-fitting time is set as the upper limit of the time for continuously press-fitting the liquid to be treated, and in this embodiment, the time during which filtration can be performed efficiently while maintaining a desired filtration capacity (for example, 25 minutes) ).

After the processing liquid stop process, a liquid removal air supply process is executed. In the drainage air supply process, the solenoid valve 7e of the air supply pipe 7b is opened, and high-pressure drainage air is supplied from the air pump outside the machine into the filter chamber 15 through the air supply pipe 7b and the common supply pipe 7c. . Further, in the drainage air supply process, when the opening operation of the electromagnetic valve 7e is started, the supply time for supplying the drainage air is started.
Then, during the supply of drainage air, it is determined whether or not the supply time has passed a predetermined drainage time, and when the drainage time has passed, the drainage air stop process is executed. In the drainage air stop process, the solenoid valve 7e of the air supply pipe 7b is closed to stop the supply of the drainage air to the filter chamber 15.

By supplying liquid removal air in this way, the liquid to be treated remaining in the filter chamber 15 is filtered, and the liquid component of the sludge remaining in the filter chamber 15 passes through the filter papers S and S and is discharged. As a result, a cake that is a lump of sludge is formed in the filter chamber 15. Furthermore, on the inner surface of the filter paper S, the dried sludge remains attached as a thin film. Thus, the process from the liquid removal air supply process to the liquid removal air stop process is the liquid removal process described above.
The liquid removal time for supplying the liquid discharge air is a time (for example, 3 minutes) that is effective when the inflow time of the liquid to be treated reaches the continuous press-fitting time (end flag = 0), A valid time (for example, 20 minutes) is set when the inflow amount per unit time becomes equal to or less than the threshold (end flag = 1), and is selected according to each case. Here, when the continuous press-fitting time has been reached (end flag = 0), the liquid removal time selected is to be treated in the filter chamber 15 to the extent that the liquid to be treated does not flow back when the next backwash air is supplied. It is defined as the time required to reduce the amount of liquid. On the other hand, the drainage time selected when the inflow amount is equal to or less than the threshold (end flag = 1) is set to a time during which cake and sludge remaining in the filter chamber 15 can be sufficiently dried.

  After the liquid removal air stop process, the backwash air supply process is executed when the process liquid stop process is executed because the inflow time of the liquid to be processed has reached the continuous press-fitting time (end flag = 0). On the other hand, when the processing liquid stop process is executed because the inflow amount per unit time is equal to or less than the threshold value (end flag = 1), the plate opening operation process is executed.

In the backwash air supply process, the electromagnetic valve 8a of the discharge pipe 8 is closed, the electromagnetic valve 9a of the air supply pipe 9 is opened, and the electromagnetic valve 17a of the air vent pipe 17 is opened. As a result, the high pressure backwash air passes through the air supply pipe 9 and the upstream portion of the discharge pipe 8 into the closed gaps 39 and 39 closed by the filter paper S and S and the grooves 34 and 34 of the filter plates 11 and 11. Supplied. Further, in the backwash air supply process, when the opening operation of the electromagnetic valve 9a is started, measurement of the supply time for supplying the backwash air is started.
Then, during the backwash air supply, it is determined whether the backwash air supply time has reached a predetermined backwash time (for example, 3 seconds). Execute. In the backwash air stop process, the solenoid valve 9a of the air supply pipe 9 is closed to stop the supply of backwash air, the solenoid valve 8a of the discharge pipe 8 is opened, and the solenoid valve 17a of the air vent pipe 17 is closed. To do.

During the supply of the backwash air, the backwash air passes through the filter papers S and S from the closed gaps 39 and 39 and enters the filter chamber 15, and accordingly, the backwash air enters the inner surfaces of the filter papers S and S. Adhering sludge can be dropped. Here, since the sludge adhering to the inner surfaces of the filter papers S and S is dried by the supply of the dewatered air, the comparison is made by backwashing air that enters the filter papers S and S from the outside to the inside. Can be easily collapsed from the inner surface. Thereby, clogging of the filter papers S and S can be eliminated. Then, sludge that has fallen from the filter papers S and S accumulates in the lower portion of the filter chamber 15. Further, since the electromagnetic valve 17 a of the air vent pipe 17 is opened while the backwash air is being supplied, the backwash air that has entered the filter chamber 15 is discharged through the air vent pipe 17. In the present embodiment, the liquid to be treated in the filter chamber 15 is filtered and reduced before the backwash air is supplied, so that the filtration chamber is supplied during the backwash air supply. It is possible to prevent the liquid to be processed remaining in 15 from flowing back from the air vent pipe 17.
Thus, the above-described backwash process is performed from the backwash air supply process to the backwash air stop process. Note that the backwash time for supplying the backwash air is determined as a time during which sludge adhering to the filter papers S and S can be crushed by the backwash air, as will be described later.

  After the backwash air stop process, the process liquid press-fitting process is started, and a series of processes are sequentially executed in the same manner as described above. In this way, the treatment liquid press-fitting step, the liquid removal treatment step, and the backwash treatment step are repeatedly executed, and the liquid to be treated can be filtered with a desired filtration capacity for a relatively long time.

  On the other hand, in the opening operation process, the electromagnetic valve 17a of the air vent pipe 17 is opened and the hydraulic cylinder 4b of the opening / closing mechanism 4 is driven and controlled to convert the filter plates 11, 11 from the closed plate state to the open plate state. Thereby, the filter plates 11 and 11 and the filter papers S and S are separated from the filter frame 10, the filter chamber 15 is opened, and the cake (and sludge) accumulated in the filter chamber 15 falls by its own weight, It is accommodated in the cake collection part 6 directly below. Here, before the opening operation process, the dewatering process is performed in which the dewatered air is supplied for a relatively long time (for example, 20 minutes), so that the dried cake can be recovered. When the filter plates 11 and 11 are converted to the open plate state, the electromagnetic valve 17a of the air vent pipe 17 is closed.

After the opening operation process, a filter paper exchange operation process is executed. In the filter paper exchange operation processing, the motor of the filter paper supply device 5 is driven and controlled, and the used filter paper S arranged on the surface of the filter plate 11 is wound around the collection roller 5b and unwound around the supply roller 5a. The used filter paper S is disposed on the surface of the filter plate 11.
In addition, after completion | finish of such filter paper replacement | exchange operation | movement process, an operator can perform a filtration process process as mentioned above by performing start operation again.

  Next, the result of measuring the filtration ability by the filter press 1 of the above-described embodiment will be described. As shown in FIG. 13, the measurement result of the filtration capacity is represented by the treatment amount (inflow amount) of the liquid to be treated in the treatment time for performing the filtration step. Here, the processing amount of the liquid to be processed indicates the amount of decrease in the liquid surface height of the liquid to be processed which is measured by the liquid meter 52 described above. This is because, as described above, the liquid surface height of the liquid to be processed is proportional to the inflow amount of the liquid to be processed, and thus can be treated substantially as being synonymous with the processing volume.

  In the present embodiment, the filtration process is executed by setting the press-fitting time in the above-described filtration process control process to 25 minutes, the drainage time to 3 minutes, and the backwash time to 3 seconds. That is, in the filtration step of the embodiment, the treatment liquid press-fitting step is continued for 25 minutes, then the liquid removal treatment step is carried out for 3 minutes, then the backwash treatment step is carried out for 3 seconds, and then the treatment liquid press-fitting step is performed again. Execute. In this way, the treatment liquid press-fitting step, the dehydration treatment step, and the backwash treatment step are sequentially repeated.

  On the other hand, as a comparative example, when the processing liquid press-fitting step (processing liquid press-fitting process) was continuously performed, the filtration capacity was measured in the same manner as in the Examples, and the measurement results of the filtration capacity are also shown in FIG. Here, in the comparative example, a filter press having the same structure as that of the example is used so that the filtration capability by the filtration process of the example described above can be clarified. That is, the measurement result of the comparative example is the filtering ability obtained by continuously executing the processing liquid press-fitting process while maintaining the open state of the electromagnetic valve 7d of the processing liquid supply pipe 7a with the same filter press 1 as in the example. is there.

  As shown in FIG. 13, the filtration capacity of the example shows that the treatment amount of the liquid to be treated temporarily stagnates every 25 minutes, but the treatment amount of the liquid to be treated rises substantially linearly. Even if it continues, it turns out that the filtration capacity has hardly fallen. On the other hand, the filtration capacity of the comparative example began to gradually decrease compared to the example from about 40 minutes later, and after about 60 minutes, the treatment amount compared to the example. Decrease in amount is increased. As described above, in the embodiment, even when the filtration is continuously performed for more than 2 hours, the decrease in the filtration capacity is extremely small and the desired filtration capacity can be maintained, so that efficient filtration can be executed. On the other hand, in the comparative example, as the processing time becomes longer, the reduction rate of the processing amount of the liquid to be processed becomes larger, and the filtering ability is lowered as compared with the example, so that the desired filtering ability cannot be maintained. For this reason, the treatment liquid press-fitting step is stopped and the filtration needs to be replaced. According to these measurement results, even in the case where the treatment liquid press-fitting process is temporarily stopped every 25, the embodiment has a higher filtering ability than the process liquid press-fitting process is continued (the amount of treatment liquid to be treated). It is clear that the filtration efficiency is generally high.

As described above, the filter press 1 of the present embodiment adheres to the inner surfaces of the filter papers S and S in the processing liquid press-fitting step by sequentially executing the processing liquid press-fitting step, the liquid removal processing step, and the backwash processing step. The sludge thus obtained can be removed relatively easily from the inner surfaces of the filter papers S and S in the backwashing process, and clogging of the filter paper S can be eliminated. Therefore, by repeatedly performing such a treatment liquid press-fitting step, a dehydration treatment step, and a backwash treatment step, a desired filtration capacity can be stably exhibited over a relatively long time. And since the frequency | count of execution of the plate opening operation | movement and filter paper replacement | exchange operation | movement required in order to replace | exchange filter paper can be reduced, filtration efficiency can be improved and the usage-amount of filter paper can be reduced. Therefore, according to the present embodiment, it is possible to realize efficiency and cost reduction of the filtration process.
Here, in the present embodiment, the liquid removal treatment process is executed before the backwash treatment process. This is because the liquid to be treated remaining in the filter chamber 15 is filtered by the liquid removal treatment process so that the liquid to be treated does not remain in the filter chamber 15 during the backwash treatment process. If the backwash process is performed without performing the liquid removal process, the liquid to be treated remaining in the filter chamber 15 may flow back from the air vent pipe 17 during the backwash process. According to the present embodiment, this backflow can be prevented by executing the liquid removal treatment step. Furthermore, since the liquid component of the sludge adhering to the inner surface of the filter paper S is discharged and dried by the liquid removal treatment step, the sludge adhering to the filter paper S can be removed relatively easily by the backwashing treatment step. There are also advantages. For this reason, as in this embodiment, the filtration ability of the filter paper S can be recovered by sequentially performing the treatment liquid injection step, the liquid removal treatment step, and the backwash treatment step, and the continuous filtration can be performed stably. be able to.

  Further, in this embodiment, in the treatment liquid press-fitting step, the filter paper is exchanged when the inflow amount of the liquid to be treated per unit time becomes smaller than a predetermined threshold value, so that it is necessary to maintain a desired filtration capacity. Replace the filter paper at an appropriate time. That is, the present embodiment can realize the efficiency and cost reduction of the filtration process described above while stably maintaining a desired filtration capacity.

  Further, in this embodiment, the filter frame 10 has a substantially inverted U shape composed of the upper edge portion 20 and both side edge portions 21 and 21 and is opened downward, so that the filter formed in a closed plate state is used. After filtering the liquid to be treated into the chamber 15 and performing filtration, the filter plate 15 is converted into an open plate state, and when both the filter plates 11, 11 constituting the bottom edge of the filter chamber 15 are separated from the filter frame 10, the filter chamber 15 The cake (sludge) that remains in the tank falls directly under its own weight. Thus, according to the present embodiment, a mechanism (or operation) for removing the cake from the filter chamber 15 is not required, and the filter plates 11 and 11 are merely separated from the filter frame 10 by converting the closed plate state to the open plate or higher. Thus, the cake can be discharged naturally from the filter chamber 15.

  Furthermore, in the present embodiment, the lower portions 21c on both sides of the filter plate 10 have a tapered shape with the lower ends being blade-shaped, so that the filter papers S and S are formed at the lower ends of the lower portions 21c (X portion in FIG. 10B). Can be pinched with almost no bending. Therefore, although the filter press 1 of this embodiment is inferior in strength to the filter cloth, it is possible to use a cheap and disposable filter paper as the filter sheet.

  In the configuration of the present embodiment described above, the filter paper S corresponds to the filter sheet according to the present invention. Further, the discharge pipe 8 corresponds to a discharge path according to the present invention. The electromagnetic valve 7d provided in the processing liquid supply pipe 7a of the supply pipe 7 corresponds to the processing liquid press-fitting means according to the present invention. Further, the electromagnetic valve 7e provided in the air supply pipe 7b of the supply pipe 7 corresponds to the dewatered air supply means according to the present invention. The electromagnetic valve 9a of the air supply pipe 9 connected to the discharge pipe 8 corresponds to the backwash air supply means according to the present invention. Moreover, the control apparatus 50 which performs a filtration process control process is equivalent to the filtration process control means concerning this invention. Further, the sealing surface portion 32 of the filter plate 11 corresponds to the bottom edge portion of the filter plate according to the present invention.

The present invention is not limited to the above-described embodiments, and configurations other than the above-described embodiments can be implemented with appropriate modifications within the scope of the present invention. Below, another example concerning the present invention is illustrated.
For example, in the present embodiment, when the inflow amount per unit time is smaller than a predetermined threshold in the state in which the liquid to be processed is injected (processing liquid injection step), the liquid injection is stopped and the liquid injection is supplied. Later, the filter paper was replaced. However, the present invention is not limited to this, and when the number of repetitions of the treatment liquid press-fitting process, the liquid removal process, and the backwash process reaches a predetermined number of times, the filter paper is replaced. Alternatively, the filter paper may be replaced when the time for repeatedly executing the backwash process from the process liquid injection process reaches a predetermined time value. That is, the conditions for terminating the treatment liquid press-fitting step, the dehydration treatment step, and the backwash treatment step (the filtration termination condition of the present invention) can be set based on the number of repetitions and the repetition time. It is.

  Further, the press-fitting time (25 minutes), the draining time (3 minutes), and the backwashing time (3 seconds) exemplified in the present embodiment are not limited to this, and can be appropriately changed and set. Specifically, it can be set as appropriate according to the size of the filter chamber, the pressure for injecting the liquid to be treated, the pressure of the dewatered air, the pressure of the backwash air, and the like.

  In this embodiment, the air supply pipe 9 for supplying the backwash air is connected to the discharge pipe 8. However, the present invention is not limited to this, and the air supply pipe for supplying the backwash air is provided in the groove portion of the filter plate. A configuration directly connected to the terminal may be used. When the air supply pipe is connected to the groove, the filtrate cannot flow into the air supply pipe, or the filtrate that flows into the air supply pipe naturally falls and flows into the discharge pipe. Is preferred.

  Further, in the present embodiment, the groove formed on the surface of the filter plate is formed in a vertical stripe lattice shape, but is not limited thereto, and can be formed in various shapes. For example, it is good also as a shape dented in a rectangular parallelepiped shape or a column shape. Furthermore, it is good also as a structure which arrange | positions a porous body inside the groove part dented in such a rectangular parallelepiped shape.

  In this embodiment, the two filter plates 11 and 11 and one filter frame 10 facing each other are provided. However, the present invention is not limited to this, and a large number of filter plates and filter frames are arranged in a row. A structure may be sufficient and can show the same effect.

  In the present embodiment, the processing liquid press-fitting process, the liquid removal processing process, and the backwashing process process are repeatedly executed in order. However, the present invention is not limited to this, and the processing liquid press-fitting process and the backwashing process process are repeatedly executed. A configuration is also possible. That is, in the configuration of this another example, the backwashing process is performed without performing the liquid removal process after the process liquid press-fitting process. Therefore, the coating remaining in the filter chamber during the backwashing process is performed. There is a possibility that the processing liquid flows backward from the air vent pipe. Therefore, the configuration of such another example is a configuration in which a retention portion for retaining the liquid to be processed that flows backward from the filter chamber is provided in the air vent pipe (at a site downstream of the solenoid valve). As a result, since the liquid to be treated that flows back from the filter chamber in the backwash process can be retained, the backflow of the liquid to be treated from the air vent pipe can be suppressed, and the same effect as the above-described embodiment can be achieved. Is possible. In the configuration of such another example, when the treatment liquid press-fitting step is terminated when the inflow rate per unit time is equal to or less than the threshold value, the plate opening step is performed after the liquid removal treatment step is performed. Thereby, before converting the filter plate from the closed plate state to the open plate state, the liquid to be treated in the filter chamber is filtered and the liquid component of the cake (sludge) in the filter chamber is discharged.

DESCRIPTION OF SYMBOLS 1 Filter press 8 Discharge pipe 10 Filter frame 11 Filter plate 15 Filter chamber 20 Upper edge part 21 Side edge part 32 Sealing surface part (bottom edge part)
34 Groove S Filter paper (filter sheet)

Claims (4)

A pair of filter plates that are arranged so as to be able to move away from each other and in which grooves that communicate with a discharge path for discharging the filtrate are formed on opposite surfaces;
A filter frame disposed between both filter plates and sandwiched by both filter plates;
A filter sheet interposed between both filter plates and the filter frame, and positioned on both sides of the filter frame in a closed plate state in which the filter frame is sandwiched by both filter plates and forming a filter chamber in the filter frame; ,
A treatment liquid press-fitting means for press-fitting a liquid to be treated into the filter chamber formed in the closed plate state;
In a filter press for filtering the liquid to be treated, which is press-fitted into the filter chamber, with a filter sheet, and discharging the filtrate to the discharge path through the groove of the filter plate,
In the closed plate state, it comprises backwash air supply means for supplying backwash air into the groove portion of the filter plate,
In the closed plate state, the processing liquid press-fitting means is operated and controlled, and a processing liquid press-fitting step of press-fitting the liquid to be processed into the filter chamber;
After stopping the press-fitting of the liquid to be treated, a backwash process step of controlling the backwash air supply means to supply backwash air into the groove located outside the filter chamber for a predetermined time, A filter press characterized by comprising filtration process control means for repeatedly controlling execution until a predetermined filtration termination condition is satisfied. In the filter chamber formed in a closed plate state in which the filter frame is sandwiched between the two filter plates, a drainage air supply means for supplying drainage air is provided,
Filtration process control means
During the treatment liquid press-fitting process and the backwash treatment process, when the liquid to be treated is stopped from being injected by the treatment liquid press-fitting means, the liquid removal air supply means is controlled to supply the liquid to the filter chamber. The filter press according to claim 1, wherein the liquid removal treatment step is performed.   The filtration end condition of the filtration process control means is that the inflow amount per unit time of the liquid to be treated that is press-fitted into the filter chamber in the treatment liquid press-fitting step is equal to or less than a predetermined threshold value. Filter press. The filter frame includes an upper edge portion that constitutes the upper edge of the filter chamber in a closed plate state, and side edge portions that respectively hang down from both ends of the upper edge portion and constitute both side edges of the filter chamber in the closed plate state. Comprising a frame shape that opens downward between both side edges, and at least the lower part of both side edges is formed in a tapered shape with the lower end as a blade edge,
4. The filter plate according to claim 1, further comprising a bottom edge portion that constitutes a bottom edge of the filter chamber by being pressed against each other via a filter sheet in the closed plate state. The filter press according to any one of the above.

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