JP2021053577A - Filter press - Google Patents

Abstract

To provide a filter press capable of appropriately performing deliquoring even when laminating a number of filter plates.SOLUTION: A discharge device 33 capable of switching to at least two states of a full-open state in which filtrate and air can be discharged from a discharge port 31 communicating with all filtration chambers 5 by opening and closing opening-closing valves V3 to V6, and a partial-open state in which filtrate and air can be discharged only from a discharge port 31 communicating with the filtration chamber 5 of one chamber or a plurality of chambers from the supply port 18 side, and filtrate and air cannot be discharged from remaining filtration chambers 5 is arranged. Therein, in a deliquoring process of discharging a liquid component from the filtration chamber 5, a full-open dewatering process of supplying air from the supply port 18 in the full open state of the discharge device 33 and a partial open dewatering process of supplying air from the supply port 18 in the partial open state of the discharge device 33 are successively performed.SELECTED DRAWING: Figure 7

Description

The present invention relates to a filter press that performs filtration in a filter chamber formed between laminated filter plates.

A filter press is known in which a liquid to be treated is supplied to a filter chamber formed between a plurality of stacked filter plates, and filtration is performed with a filtration sheet sandwiched between the filter plates. In such a filter press, the filter plates are held so as to be movable apart in the stacking direction, and after the filtration is completed, the filter plates are separated from each other to open the filter chamber, and the filtered substance is dropped from the filter chamber. Further, before opening the filter chamber, a deliquesing step is performed in which air is press-fitted into the filter chamber, a liquid component is discharged from the filter chamber together with air, and the filtered substance in the filter chamber is made into a dry cake.

In the filter press, the liquid to be treated and air are press-fitted into the filter chamber on one end side from the supply port formed on one end side in the stacking direction of the filter plates. The filter plate is formed with a communication port that penetrates in the thickness direction and communicates with the adjacent filter chambers, and the liquid to be treated and air press-fitted into the filter chamber on one end side pass through the communication port to the other. It is supplied to the filter chamber on the end side. Then, the liquid to be treated and the air supplied to each filter chamber pass through the filtration sheet and are discharged to the outside from the discharge port opened at the outer peripheral portion of the filter plate (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 9-155111

In the conventional filter press, the liquid to be treated and air are sequentially supplied from the filter chamber on the supply port side to the other end side through the communication port of the filter plate, so that the filter on the other end side far from the supply port is supplied. In the chamber, the pressure of the liquid to be treated and the air is lower than that of the filter chamber on the supply port side due to the pressure loss due to friction or the like when passing through the communication port. Therefore, in the conventional configuration, in the filter chamber on the other end side far from the supply port, the efficiency of filtration and deliquescent is lower than that in the filter chamber on the supply port side by the pressure difference between the liquid to be treated and the air. There is. If the number of laminated filter plates is relatively small, the pressure difference between the supply port side and the other end side is small, so no problem occurs. However, if the number of laminated filter plates is relatively large, the supply port side and the other end side As the pressure difference in the filter chamber becomes large, problems occur during filtration and deliquescent.

Specifically, in the filtration step, the filter chamber on the supply port side with high filtration efficiency fills up earlier than the filter chamber on the other end side, and the filtered substance accumulated in the filter chamber on the supply port side is the filter plate. Since the communication port is blocked, there arises a problem that the filtered substance cannot be sufficiently accumulated in the filter chamber on the other end side. On the other hand, in the liquid removal step, the filter chamber on the supply port side is drained earlier than the filter chamber on the other end side, but when the filter chamber on the supply port side is sufficiently drained, the filter chamber is concerned. Since the air is easily released from the air and the pressure of the air press-fitted into the supply port decreases, it may take time to deliquesce the filter chamber on the other end side, which has low deliquescent efficiency, or the deliquescent may be insufficient. There is a problem that it is easy to do.

The present invention has been made in view of the present situation, and an object of the present invention is to provide a filter press capable of appropriately performing filtration and / or liquid removal even when a large number of filter plates are laminated.

In the present invention, a plurality of filter plates are laminated with a filter sheet sandwiched between them, and a filter press main body forming a filter chamber between adjacent filter plates and the filter press main body are closed by tightening the filter plates in the stacking direction. A filter press including a plate state and an opening / closing device that separates adjacent filter plates into an open state in which the filter chamber can be opened. The filter press main body is in a stacking direction of the filter plates. A supply port formed on one end side of the filter medium and communicating with the filter chamber on the one end side and a communication port penetrating the filter plate in the thickness direction and communicating with each other on both sides of the filter plate. A port, a plurality of discharge ports for discharging the filtrate and air in the filter chamber to the outside in communication with the filter chamber are provided, and the liquid to be treated and the air are discharged from the supply port to the filter chamber on one end side. A discharge device including a supply device that can be selectively press-fitted, a discharge pipe that draws out a filtrate and air from each of the discharge ports, and an on-off valve that can open and close the discharge pipe, the on-off device, and the above-mentioned The control device includes a supply device and a control device that controls the discharge device, and the control device includes a plate closing step of converting the filter press main body from the open plate state to the closed plate state by the opening / closing device, and the supply device. The liquid to be treated is press-fitted into the filter chamber from the supply port, filtered by a filtration sheet, and the filtrate that has passed through the filtration sheet is discharged from the discharge port by the discharge device, and the supply port by the supply device. The filter press main body is moved from the closed plate state by the opening and closing device, and the liquid removal step of injecting air into the filter chamber from the filter chamber and discharging the liquid component in the filter chamber together with the air from the discharge port by the discharge device. The plate opening step of converting to the plate open state is sequentially executed, and the discharge device has a fully open state in which the filtrate and air can be discharged from all the filter chambers by opening and closing the on-off valve, and the one end side. It is possible to switch to at least two states of the first partially open state in which the filtrate and air cannot be discharged in the predetermined number of the filter chambers and the filtrate and air can be discharged in the remaining filter chambers. In the liquid removal step, after the first fully open liquid removal step of controlling the discharge device to the fully open state and supplying air from the supply port and the first fully open liquid removal step, The filter press is characterized in that the discharge device is controlled to the first partially open state and the first partially open deliquescent step of supplying air from the supply port is executed.

In such a configuration, in the first partially open liquid removal step, the filtrate and air cannot be discharged in the filter chamber on one end side having high liquid removal efficiency, so that relatively high pressure air is supplied to the filter chamber on the other end side. it can. Therefore, in the present invention, if the first partially open deliquescent step is executed after the filter chamber on one end side is sufficiently deliquescent in the first fully open deliquescent step, the other end side is compared with the conventional configuration. It becomes easy to dry the filtered substance in the filter chamber in a short time, and the risk of ending the liquid removal step with insufficient liquid removal in the filter chamber on the other end side is reduced. Therefore, the filter press of the present invention has an advantage that a problem does not easily occur in the liquid removal even when a relatively large number of filter plates are laminated.

Further, in the present invention, the supply device includes an air pressure measuring means capable of measuring the pressure of air press-fitted into the supply port, and the control device is provided with the air pressure during the first fully open deliquessing step. It is proposed that the first fully open deliquessing step is terminated when the measured value of the measuring means drops to a predetermined value.

In the first fully open deliquescent step, when the filter chamber on one end side (supply port side) is sufficiently deliquescent, the pressure of the air press-fitted into the supply port decreases. If the pressure drop of the air press-fitted into the supply port is used as an opportunity to terminate the first fully open deliquescent step and execute the next step, the deliquescent step can be efficiently performed.

Further, in the present invention, it is also proposed that the control device ends the first fully open liquid removal step when a predetermined time has elapsed from the start of the first fully open liquid removal step. ..

In the first fully open deliquessing step, the timing at which the filter chamber on one end side (supply port side) is sufficiently deliquesed largely depends on the processing time. Even if the first fully open liquid removal step is terminated and the next step is executed when the predetermined time has elapsed, the liquid removal step can be efficiently performed.

Further, in the present invention, the discharge device cannot discharge the filtrate and air from the one end side in a predetermined number of filter chambers by opening and closing the on-off valve, and can discharge the filtrate and air in the remaining filter chambers. The number of the filter chambers that can be switched to the second partially open state and the filtrate and air cannot be discharged in the second partially open state is such that the filtrate and air cannot be discharged in the first partially open state. The number of filter chambers is smaller than the number of the filter chambers, and the control device is the discharge device in the liquid removal step after the first fully open liquid removal step and before the first partially open liquid removal step. It is proposed to control the second partially open state to execute the second partially open deliquescent step of supplying air from the supply port.

In such a configuration, in the liquid removal step, the filter chamber is divided into a plurality of stages from one end side (supply port side) and liquid removal becomes impossible. Therefore, even when a relatively large number of filter plates are laminated, the liquid removal step is performed. It becomes possible to do it more appropriately.

Further, in the present invention, at the end of the liquid removal step, the control device controls the discharge device to the fully open state and performs a second fully open liquid removal step of supplying air from the supply port. Suggested to do.

In such a configuration, by executing the second fully open liquid removal step at the end of the liquid removal step, it is possible to completely discharge a small amount of liquid component that has not been discharged from the filter chamber.

In another aspect of the present invention, a filter press main body in which a plurality of filter plates are laminated with a filter sheet sandwiched thereto to form a filter chamber between adjacent filter plates, and the filter press main body are adjacent to each other. A filter press including an opening / closing device for converting a closed plate state in which the filter chambers are formed close to each other and an open plate state in which the filter chambers are separated from each other to open the filter chamber. The filter press main body is formed on one end side in the stacking direction of the filter plates, and has a supply port communicating with the filter chamber on the one end side and both sides of the filter plates penetrating the filter plates in the thickness direction. It is provided with a communication port for communicating with each other and a plurality of discharge ports for discharging the filtrate and air in the filter chamber to the outside by communicating with the filter chamber. It is provided with a supply device capable of selectively press-fitting the liquid to be treated and air into the filter chamber on one end side, a discharge pipe for drawing out the filtrate and air from each of the discharge ports, and an on-off valve capable of opening and closing the discharge pipe. A control device for controlling the discharge device, the opening / closing device, the supply device, and the discharge device is provided, and the control device closes the filter press main body from the open plate state by the opening / closing device. A plate closing step of converting to a plate state, and filtration in which the liquid to be processed is press-fitted from the supply port into the filter chamber by the supply device, filtered by a filtration sheet, and the permeated filtrate is discharged from the discharge port by the discharge device. A step, a deliquescent step of injecting air from the supply port into the filter chamber by the supply device, and discharging the liquid component and air in the filter chamber from the discharge port by the discharge device, and the opening / closing device. The plate opening step of converting the filter press main body from the closed plate state to the open plate state is sequentially executed, and the discharge device can discharge the filtrate and air in all the filter chambers by opening and closing the on-off valve. At least two states, a fully open state in which the filtrate and air cannot be discharged from the one end side in a predetermined number of filter chambers, and a first partially open state in which the filtrate and air can be discharged in the remaining filter chambers. The control device is switchable, and in the filtration step, the first partially open filtration step of controlling the discharge device to the first partially open state and supplying the liquid to be processed from the supply port, and the said The filter press is characterized in that after the first partially open filtration step, the discharge device is controlled to be in a fully open state, and a fully open filtration step of supplying the liquid to be processed from the supply port is executed.

In such a configuration, since the first partially open filtration step is executed before the fully open filtration step, the filter chamber on the other end side has a filter chamber on the one end side (supply port side) as compared with the filter chamber on the one end side (supply port side). Filtration is started early and is also performed for a long time. Therefore, with such a configuration, the filter chamber on the other end side can be filled with the filtering substance before the filter chamber on the one end side having high filtration efficiency, and a relatively large number of filter plates are laminated. Even so, in the filtration step, the filtered substance can be sufficiently accumulated up to the filter chamber on the other end side.

Further, in the present invention, the supply device includes a hydraulic pressure measuring means capable of measuring the pressure of the liquid to be press-fitted into the supply port, and the control device is used during the first partially open filtration step. It is proposed that the first partially open filtration step is terminated when the measured value of the hydraulic pressure measuring means rises to a predetermined value.

In the first partially open filtration step, as the filtered material is accumulated in the filter chamber on the other end side, the pressure of the liquid to be press-fitted into the supply port by the supply device increases. If the first partially open filtration step is terminated and the next step is executed with the pressure rise of the liquid to be press-fitted into the supply port as an opportunity, the filtration step can be efficiently performed.

Further, in the present invention, it is also proposed that the control device ends the first partially open filtration step when a predetermined time has elapsed from the start of the first partially open filtration step. ..

In the first partially open filtration step, the amount of the filtered substance accumulated in the filter chamber on the other end side largely depends on the treatment time. Therefore, the treatment time of the first partially open filtration step is measured for a predetermined time. The filtration step can be efficiently performed even if the first partially open filtration step is terminated and the next step is executed in the wake of the elapse of the above.

Further, in the present invention, the discharge device cannot discharge the filtrate and air from the one end side in a predetermined number of filter chambers by opening and closing the on-off valve, and can discharge the filtrate and air in the remaining filter chambers. The number of the filter chambers that can be switched to the second partially open state and the filtrate and air cannot be discharged in the second partially open state is such that the filtrate and air cannot be discharged in the first partially open state. Less than the number of filtration chambers, the control device puts the discharge device into the second portion of the filtration step after the first partially open filtration step and before the fully open filtration step. It is proposed to perform a second partially open filtration step of supplying the liquid to be treated from the supply port by controlling the open state.

In such a configuration, in the filtration step, the filter chamber can be filtered from the other end side in a plurality of stages, so that the filtration step can be performed more appropriately even when a relatively large number of filter plates are laminated. It becomes.

Further, in the present invention, the supply device includes an air pressure measuring means capable of measuring the pressure of air press-fitted into the supply port, and the discharge device is provided in all the filter chambers by opening and closing the on-off valve. It is possible to switch to a fully closed state in which the filtrate and air cannot be discharged, and the control device is in a state in which the discharge device is controlled to the fully closed state after the plate closing step and before the filtration step. Then, the seal confirmation step of injecting air from the supply port into the filter chamber by the supply device is executed, and in the seal confirmation step, if the measured value of the air pressure measuring means does not reach the specified value, an error is determined. Is proposed.

In such a configuration, if the filter chamber is not kept in an airtight state due to foreign matter being caught between the filter plates, an error can be detected in the seal confirmation step, so that the filter chamber is not sufficiently sealed. The filtration step can be performed to prevent the liquid to be treated from leaking out of the filter chamber.

As described above, according to the filter press of the present invention, it is possible to appropriately perform filtration and liquid removal even when a relatively large number of filter plates are laminated.

It is a flow sheet of the filter press 1. It is sectional drawing of the filter press main body 2. It is a perspective view of the filter plate 3. It is explanatory drawing which shows the seal confirmation process. (A) is explanatory drawing which shows the 1st partial open filtration process. (B) is explanatory drawing which shows the 2nd partial open filtration process. (A) is explanatory drawing which shows the 3rd partial open filtration process. (B) is an explanatory diagram showing a fully open filtration step. (A) is explanatory drawing which shows the 1st full-open liquid removal process. (B) is explanatory drawing which shows the 1st partial open liquid removal process. (A) is explanatory drawing which shows the 2nd partial open liquid removal process. (B) is an explanatory view which shows the 3rd partial open liquid removal process. It is a graph which shows the change of the pressure of the liquid to be treated measured by a pressure gauge 29 in a filtration process. It is a graph which shows the change of the pressure of compressed air measured by a pressure gauge 29 in a liquid removal process.

Hereinafter, embodiments of the present invention will be specifically described with reference to Examples.
In the following examples, the control device according to the present invention corresponds to the control panel 50. Further, the on-off valve of the discharge device according to the present invention corresponds to the solenoid valves V3 to V6. Further, the air pressure measuring means according to the present invention corresponds to a pressure gauge 29. Further, one end side of the filter press main body according to the present invention corresponds to the fixed end side (supply port 18 side).

FIG. 1 is a flow sheet of the filter press 1 of this embodiment. As shown in FIG. 1, the filter press 1 of the present embodiment has a filter press main body 2, an opening / closing device 7 that converts the filter press main body 2 into an open plate state and a closed plate state, and a liquid to be processed on the filter press main body 2. A supply device 20 for supplying compressed air, a cake collecting unit 38 for collecting cake discharged from the filter press main body 2, and a control panel 50 for controlling the operation of the filter press 1 are provided. The filter press 1 of this embodiment is a so-called fully automatic type, and the control panel 50 controls each device in an integrated manner to supply the liquid to be treated, dry the filtered substance, and dry the filtered substance (cake). Ejection is done automatically. Such a filter press 1 is suitably used for applications such as filtering and collecting cutting chips from waste liquid containing cutting chips generated in metal processing.

The filter press main body 2 is a single type that does not have a filter frame, and has a configuration in which a filter cloth 4 is sandwiched between a plurality of stacked filter plates 3 and the filter plates 3. In the filter press main body 2, one end in the stacking direction of the filter plate 3 is a fixed end (fast head) and the other end is a movable end (loose head), and the movable end is moved to the fixed end side to filter. A closed plate state in which a filter cloth 4 is sandwiched between adjacent filter plates 3 to form a filter chamber 5 (see FIG. 2) by tightening the plates 3 in the stacking direction, and a direction in which the movable end is separated from the fixed end. By moving the filter plates 3 to, the filter plates 3 can be separated from each other, and the filter chamber 5 can be converted into an open plate open state.

The opening / closing device 7 presses the opening / closing mechanism 8 that holds the filter plate 3 so as to be movable in the distance, the opening / closing motor 9 that drives the opening / closing mechanism 8 to move the filter plate 3 in the distance, and the filter plate 3 from the movable end side. A hydraulic cylinder 10 for tightening the filter press main body 2 in the stacking direction and a hydraulic pump 11 for operating the hydraulic cylinder 10 are provided.

A filter cloth holding device 13 for holding the filter cloth 4 is arranged above and below the filter press main body 2. The filter cloth holding device 13 is stretched in the vertical direction so that the filter cloth 4 is not wrinkled even when the filter press main body 2 is in the open state. Further, above the filter press main body 2, a vibrating device 14 for vibrating the filter cloth 4 in the open plate state to peel the cake from the filter cloth 4 is arranged.

The filter press main body 2 is provided with end plates 16a and 16b, respectively, on the fixed end side (left side in the drawing) and the movable end side (right side in the drawing). The end plate 16a on the fixed end side is provided with a supply port 18 for supplying the liquid to be treated or compressed air to the filter chamber 5 on the fixed end side in the thickness direction (see FIG. 2). Further, the tip of the rod of the hydraulic cylinder 10 of the switchgear 7 is fixed to the end plate 16b on the movable end side. Further, below the filter press main body 2, a cake collecting unit 38 that receives the cake that falls from the filter press main body 2 when the plate is changed from the closed plate state to the open plate state is arranged.

A supply device 20 capable of selectively supplying the liquid to be processed and compressed air to the supply port 18 is connected to the supply port 18 of the filter press main body 2. The supply device 20 includes a common pipe 22 communicating with the supply port 18, a liquid to be treated liquid supply pipe 23 for supplying the liquid to be treated from the liquid tank to be treated (not shown) outside the machine to the common pipe 22, and the outside of the machine. An air supply pipe 24 for supplying compressed air from the air compressor (not shown) to the common pipe 22 is provided. The liquid to be treated 23 is provided with a liquid to be pump 26 for pumping the liquid to be treated and an electromagnetic valve V1 for opening and closing the liquid to be treated 23. Further, the air supply pipe 24 is provided with a regulator 28 for adjusting the pressure of compressed air and a solenoid valve V2 for opening and closing the air supply pipe 24. Further, the common pipe 22 is provided with a pressure gauge 29 that measures the hydraulic pressure of the liquid to be processed and the pressure of the compressed air that are pressure-fed to the supply port 18.

As shown in FIG. 2, the filter press main body 2 is formed by laminating 19 filter plates 3, and in the closed state, between the filter plates 3 and between the filter plates 3 and the end plates 16a and 16b. A total of 20 filter chambers 5 are formed between them. As described above, the liquid to be treated and the air are supplied from the supply port 18 formed on the fixed end side. The liquid to be treated and air supplied from the supply port 18 are first supplied to the filter chamber 5 on the fixed end side, pass through the communication port 45 formed in each filter plate 3, and enter the filter chamber 5 on the movable end side. It will be supplied sequentially. Then, the filtered substance contained in the liquid to be treated is filtered out by the filter cloth 4 in each filter chamber 5, and the filtrate and air that have passed through the filter cloth 4 are discharged to the outside.

In the filter press 1 of this embodiment, the filtrate and air that have passed through the filter cloth 4 are discharged from the filter chamber 5 in a so-called open manner. That is, the filtrate and air that have passed through the filter cloth 4 in the filter chamber 5 are discharged from the discharge port 31 (see FIG. 2) that opens on the lower side surface of each filter plate 3. The filter press 1 is provided with a discharge device 33 capable of selectively deriving the filtrate and air from each discharge port 31. Specifically, the discharge device 33 includes discharge pipes 35 to 37 for leading the filtrate and air from each discharge port 31 to a filtrate tank (not shown) outside the machine, and solenoid valves V3 to V6 capable of opening and closing the discharge pipe 36. It is composed of. The discharge pipes 35 to 37 are connected to each discharge port 31 and are formed by merging the individual discharge pipes 35 that discharge the filtrate and air from the discharge port 31 to the outside and four or five individual discharge pipes 35. It is composed of an intermediate discharge pipe 36 of a book and a whole discharge pipe 37 formed by merging four intermediate discharge pipes 36.

Solenoid valves V3 to V6 of the discharge device 33 are arranged one by one in each intermediate discharge pipe 36, and by selectively opening and closing each intermediate discharge pipe 36 by the solenoid valves V3 to V6, the filter chamber 5 It is possible to control the discharge of the filtrate and air in block units. Specifically, when the solenoid valve V3 is opened, the filtrate and air can be discharged from the 1st to 6th filter chambers 5 from the fixed end side (supply port 18 side). Similarly, the 6th to 11th filter chambers 5 when the solenoid valve V4 is open, the 11th to 16th filter chambers 5 when the solenoid valve V5 is open, and the 16th to 20th filters when the solenoid valve V6 is open. The filtrate and air can be discharged from the chamber 5. In the following description, "the nth filter chamber from the fixed end side (supply port 18 side)" is simply abbreviated as "nth filter chamber".

As shown in FIG. 3, the filter plate 3 is a rectangular plate-shaped resin molded product. The filter plate 3 has a square-shaped outer peripheral portion 40 serving as a sandwiching portion for sandwiching the filter cloth 4 between adjacent filter plates 3, and a recess 41 formed inside the outer peripheral portion 40 is adjacent to the filter plate 3. It is a filter chamber forming portion that forms a filter chamber 5 between the filter plates 3. The filter plate 3 has a symmetrical shape on the front and back surfaces, and the outer peripheral portion 40 and the recess 41 shown in FIG. 3 are formed on the front and back surfaces of the filter plate 3. In the lower corner of the filter plate 3, the above-mentioned discharge port 31 is formed so as to communicate the lower portion of the recess 41 on the front and back surfaces with the outer surface of the filter plate 3. Further, a large number of vertical ribs 43 supporting the filter cloth 4 are formed on the bottom surface of the recess 41, and the filtrate and air that have passed through the filter cloth 4 pass through the groove between the ribs 43 and are discharged from the outlet 31. It is configured to be discharged from. Further, on the bottom of the concave portion 41, convex portions 44 having the same height as the outer peripheral portion 40 are arranged at four locations, and the convex portions 44 of the adjacent filter plates 3 are brought into contact with each other in a closed state. , The filter plate 3 is configured to withstand the fastening force of the hydraulic cylinder 10. Further, in the lower part of the recess 41, the above-mentioned communication port 45 is formed so as to penetrate the filter plate 3 in the thickness direction, and the communication port 45 allows the adjacent filter chambers 5 with the filter plate 3 to be interposed. Communicate with each other (see FIG. 2).

The control panel 50 that controls the filter press 1 executes each process from closing the filter press main body 2 to filtering, removing liquid, and opening the plate by controlling the opening / closing device 7, the supply device 20, the discharging device 33, and the like. Let me. Here, the control panel 50 monitors the measured value of the pressure gauge 29 of the supply device 20 and reflects the measured value in the control process. Since most of the configurations of the filter press 1 of the present embodiment are the same as those of the existing filter press except for the main parts of the present invention described later, details other than the main parts of the present invention are detailed. The description is omitted.

The filter press 1 of this embodiment is a fully automatic type in which each process is automatically executed by the control panel 50. Specifically, the filter press 1 operates continuously by repeating the following steps (1) to (5) in order, triggered by a start operation by the operator.
(1) Plate closing process (2) Seal confirmation process (3) Filtration process (4) Liquid removal process (5) Plate opening process

The plate closing step is a step of converting the filter press main body 2 from the plate open state to the plate closed state. In the plate closing step, the control panel 50 keeps the filter press main body 2 in the closed plate state by operating the hydraulic pump 11 and tightening the filter press main body 2 in the stacking direction of the filter plates 3 by the hydraulic cylinder 10. As a result, the filter cloth 4 is sandwiched between the adjacent filter plates 3, and the filter chamber 5 is formed.

The seal confirmation step is a step of confirming whether or not the filter chamber 5 is properly sealed in the filter press main body 2 converted to the closed plate state. In the seal confirmation step, as shown in FIG. 4, the control panel 50 is in a fully closed state in which all the solenoid valves V3 to V6 are closed and the filtrate and air cannot be discharged from all the filter chambers 5. To control. Then, the solenoid valve V2 (see FIG. 1) of the air supply pipe 24 of the supply device 20 is opened, and the compressed air is supplied from the supply port 18 to the filter chamber 5. In such a state, if all the filter chambers 5 are properly maintained in an airtight state, the compressed air supplied from the supply port 18 to the filter chamber 5 loses its place, so that the measured value of the pressure gauge 29 is the regulator 28. It will rise to the pressure of the compressed air supplied from. On the other hand, if some of the filter chambers 5 are not kept in an airtight state due to impurities being caught in the outer peripheral portion 40 of the filter plate 3, compressed air leaks from the filter chamber 5 to the outside, so that the pressure is increased. A total of 29 measurements will be lower than if they were normally sealed. Therefore, in the seal confirmation step, the control panel 50 assumes that the filter chamber 5 is correctly sealed when the measured value of the pressure gauge 29 rises to a specified value within a predetermined time from the start of supply of compressed air. , The solenoid valve V2 of the air supply pipe 24 is closed to end the seal confirmation step, and the process proceeds to the filtration step. On the other hand, if the measured value of the pressure gauge 29 does not rise to the specified value within a predetermined time from the start of the supply of compressed air, the control panel 50 determines that an error occurs and closes the solenoid valve V2 of the air supply pipe 24. The seal confirmation process is completed, and the occurrence of an error is notified without shifting to the filtration process.

As described above, in this embodiment, in the seal confirmation step before the filtration step, in order to confirm whether or not the filter chamber 5 is kept in an airtight state, the filtration step is performed in a state where the filter chamber 5 is not sufficiently sealed. This can prevent the liquid to be treated from leaking from the filter chamber 5.

The filtration step is a step of supplying the liquid to be treated from the supply port 18 to the filter chamber 5, filtering the liquid to be treated inside the filter chamber 5, and discharging the filtrate that has passed through the filter cloth 4 from the discharge port 31. The filtrate discharged from each discharge port 31 in the filtration step is led out to the filtrate tank from the discharge device 33 connected to the discharge port 31. Here, in the filtration step, first, the filter chamber 5 for filtering the liquid to be treated is limited to a part of the filter chamber 5 on the movable end side, and then the filter chamber 5 for filtering the liquid to be treated is fixed stepwise. It expands to the filter chamber 5 on the end side, and finally all the filter chambers 5 are used to filter the liquid to be treated.

Specifically, in the filtration step, a partially open filtration step is performed by closing a part of the solenoid valves V3 to V6 of the discharge device 33, and a fully open filter step is performed by opening all the solenoid valves V3 to V6 of the discharge device 33. A filtration step is performed. The partially open filtration step consists of three types of partially open filtration steps in which the solenoid valves V3 to V6 that are closed are different. In the filtration step, three types of partially open filtration steps and a fully open filtration step are executed in the following order. ..
(1) First partial open filtration step (closes solenoid valves V3 to V5)
(2) Second partial open filtration process (closes solenoid valves V3 and V4)
(3) Third part open filtration process (closes solenoid valve V3)
(4) Fully open filtration process

More specifically, after the seal confirmation step is completed, the control panel 50 opens one solenoid valve V6 of the discharge device 33 as shown in FIG. 5A, and the 16th to 20th filters are opened. The first partial open state is controlled so that the filtrate and air can be discharged only from the chamber 5. Then, the solenoid valve V1 of the liquid to be treated pipe 23 of the supply device 20 is opened, and the liquid to be treated is press-fitted into the filter chamber 5 from the supply port 18 to start the first partial open filtration step. The first partially open filtration step corresponds to the first partially open filtration step according to the present invention.

In the first partially open filtration step, the liquid to be treated is filtered only in the 16th to 20th filter chambers 5, and the filtrate is discharged from the discharge port 31. When the first partially open filtration step is continued, the filtered mud-like filter substance (sludge) 60 is accumulated in the 16th to 20th filter chambers 5. Therefore, as shown in FIG. 9, in the first partially open filtration step, the filtration efficiency gradually decreases due to the filtering substance 60 accumulated in the filter chamber 5, and the hydraulic pressure of the liquid to be treated increases. When the hydraulic pressure of the liquid to be treated reached by the pressure gauge 29 reaches the predetermined threshold value P1, the control panel 50 opens the closed solenoid valve V5 to perform the first partial open filtration step to the second partial open filtration. Move to the process.

In the second partially open filtration step, as shown in FIG. 5B, the two solenoid valves V5 and V6 of the discharge device 33 can be opened to discharge the filtrate and air from the 11th to 20th filter chambers 5. The second part is controlled to the open state. In this step, the liquid to be treated can be newly filtered in the eleventh to fifteenth filter chambers 5, so that the hydraulic pressure of the liquid to be treated is temporarily reduced as shown in FIG. However, even in the second partially open filtration step, the filtered substance 60 accumulates in the filter chamber 5, so that the liquid pressure of the liquid to be treated increases. Then, when the hydraulic pressure of the liquid to be treated measured by the pressure gauge 29 reaches the predetermined threshold value P1, the control panel 50 opens the closed solenoid valve V4 to shift to the third partial open filtration step.

In the third partially open filtration step, as shown in FIG. 6A, the three solenoid valves V4 to V6 of the discharge device 33 can be opened to discharge the filtrate and air from the sixth to twentieth filter chambers 5. 3rd part is controlled to the open state. In this step, the liquid to be treated can be newly filtered in the 6th to 10th filter chambers, so that the hydraulic pressure of the liquid to be treated is temporarily reduced as shown in FIG. However, even in the third partial open filtration step, the filtered substance 60 accumulates in the filter chamber 5, so that the liquid pressure of the liquid to be treated increases. Then, when the hydraulic pressure of the liquid to be treated measured by the pressure gauge 29 reaches the predetermined threshold value P1, the control panel 50 opens the closed solenoid valve V3 to shift to the fully open filtration step.

In the fully open filtration step, as shown in FIG. 6B, all the solenoid valves V3 to V6 of the discharge device 33 are opened so that the filtrate and air can be discharged from all the filter chambers 5 in a fully open state. Control. In this step, the liquid to be treated can be newly filtered in the first to fifth filter chambers, so that the hydraulic pressure of the liquid to be treated is temporarily reduced as shown in FIG. However, even in the fully open filtration step, the filtered substance 60 accumulates in all the filter chambers 5, so that the liquid pressure of the liquid to be treated increases. Then, when the hydraulic pressure of the liquid to be treated reached by the pressure gauge 29 reaches the predetermined threshold value P2, the control panel 50 closes the solenoid valve V1 of the liquid supply pipe 23 to be treated and the liquid to be treated from the supply port 18. The supply of water is stopped, the filtration process is terminated, and the process proceeds to the deliquescent process.

As described above, in the filtration step, the liquid to be treated can be gradually filtered from the filter chamber 5 on the movable end side, so that the filter chamber 5 on the movable end side is compared with the filter chamber 5 on the fixed end side. , Filtration of the liquid to be treated is started early and is executed for a long time. Therefore, in such a filtration step, even if the filter chamber 5 on the fixed end side has higher filtration efficiency, the filter chamber 5 on the movable end side is filled with the filtering substance 60 before the filter chamber 5 on the fixed end side. It becomes possible to. Therefore, in this embodiment, even if a large number of filter plates 3 are stacked, more filtering material 60 can be accumulated in the filter chamber 5 on the movable end side in the filtration step than in the conventional case.

Further, in this embodiment, the hydraulic pressure of the liquid to be treated supplied to the supply port 18 in the filtration step is measured by the pressure gauge 29, and based on the measured value of the hydraulic pressure, the filter chamber 5 on the movable end side is appropriately used. Since each process is switched at the timing when a large amount of filtered material is accumulated, the filtration process can be performed efficiently.

The liquid removal step is a step of supplying compressed air from the supply port 18 to the filter chamber 5 and discharging the liquid component remaining inside the filter chamber 5 together with the air from the discharge port 31. By this step, the filtered substance accumulated in the filter chamber 5 is changed from a muddy substance (sludge) to a dry mass (cake). Further, the air and the filtrate discharged from each discharge port 31 in the liquid removal step are led out to the filtrate tank from the discharge device 33 connected to the discharge port 31. Here, in the liquid removal step, first, the liquid is removed in all the filter chambers 5, and then the filter chamber 5 for performing the liquid removal is gradually limited to the filter chamber 5 on the movable end side.

Specifically, in the liquid removal step, a fully open liquid removal step is performed by opening all the solenoid valves V3 to V6 of the discharge device 33, and a part of the solenoid valves V3 to V6 of the discharge device 33 is closed. It is roughly divided into a partially open deliquessing process. The partially open liquid removal process consists of three types of partially open liquid removal steps in which the solenoid valves V3 to V6 that are closed are different. In the liquid removal process, a fully open liquid removal process and three types of partially open liquid removal are performed in the following order. The liquid process is performed.
(1) First fully open liquid removal process (2) First partial open liquid removal process (close the solenoid valve V3)
(3) Second part open liquid removal process (closes solenoid valves V3 and V4)
(4) Third part open liquid removal process (closes solenoid valves V3 to V5)
(5) Second fully open liquid removal process

More specifically, the control panel 50 opens the solenoid valve V2 of the air supply pipe 24 of the supply device 20 after the completion of the filtration step, press-fits compressed air from the supply port 18 into the filter chamber 5, and presses the compressed air into the filter chamber 5. , As shown in FIG. 7A, the first fully open deliquescent step is started by controlling the discharge device 33 to the fully open state continuously from the fully open filtration step. In the first fully open liquid removal step, the remaining liquid component permeates the filter cloth 4 together with the compressed air in all the filter chambers 5 and is discharged from the discharge port 31. Then, the mud-like filter substance (sludge) 60 remaining in the filter chamber 5 becomes a dry lumpy cake 61 due to the discharge of the liquid component. Since the cake 61, which is a dry mass, has higher air permeability than the muddy sludge 60, as shown in FIG. 9, in the first fully open deliquessing step, compressed air is generated as the sludge 60 changes to the cake 61. Will easily pass through the filter cloth 4, and the pressure of the compressed air will decrease.

Here, in the first fully open liquid removal step, the pressure of the compressed air supplied is higher and the discharge efficiency of the liquid component is higher in the filter chamber 5 closer to the supply port 18, so that the fixed end side (supply port 18 side) Liquid removal proceeds faster in the filter chamber 5 than on the movable end side. Then, when the filter chamber 5 on the fixed end side is sufficiently deliquesed, the filtered substance in the filter chamber 5 becomes a cake 61 having high air permeability, so that air can easily escape from the filter chamber 5, and this As a result, in the filter chamber 5 on the other end side, the pressure of the supplied air decreases, and the liquid removal efficiency decreases. Therefore, the control panel 50 closes the open solenoid valve V3 at the timing when the filter chamber 5 on the fixed end side is sufficiently drained, and the first partial open drainage step is performed from the first fully open liquid drainage step. Move to the liquid process. Specifically, as shown in FIG. 9, the control panel 50 monitors the measured value of the pressure gauge 29, and when the pressure of the compressed air measured by the pressure gauge 29 drops to a predetermined threshold P3, the fixed end The transition from the first fully open deliquescent step to the first partially open deliquescent step is regarded as the timing when the side filter chamber 5 is sufficiently deliquescent.

In the first partially open liquid removal step, as shown in FIG. 7B, the three solenoid valves V4 to V6 of the discharge device 33 can be opened to discharge the filtrate and air from the 6th to 20th filter chambers 5. 3rd part is controlled to the open state. In this step, air and the filtrate cannot be discharged from the sufficiently deflated 1st to 5th filter chambers 5, so that the pressure of the compressed air temporarily increases as shown in FIG. However, even in the first partially open deliquescent step, the deliquescent is performed in the sixth to twentieth filter chambers 5 and the filter substance 60 dries. Therefore, in the first partially open deliquesce step, the filter substance 60 The air permeability of the air is gradually improved, and the pressure of the compressed air decreases. Therefore, the control panel 50 closes the open solenoid valve V4 when the pressure of the compressed air measured by the pressure gauge 29 drops to the predetermined threshold value P3, as in the first fully open liquid removal step. The second partial open deliquescent step is started. The second partially open deliquescent step corresponds to the second partially open deliquescent step according to the present invention.

In the second partially open liquid removal step, as shown in FIG. 8A, the two solenoid valves V5 and V6 of the discharge device 33 can be opened to discharge the filtrate and air from the 11th to 20th filter chambers 5. The second part is controlled to the open state. In this step, air and the filtrate cannot be discharged from the sufficiently deflated 1st to 10th filter chambers 5, so that the pressure of the compressed air temporarily increases as shown in FIG. However, also in the second partially open deliquescent step, the deliquescent is performed in the 11th to 20th filter chambers 5 and the filter substance 60 dries. Therefore, in the second partially open deliquesce step, the filter substance 60 The air permeability of the air is gradually improved, and the pressure of the compressed air decreases. Therefore, the control panel 50 closes the open solenoid valve V5 when the pressure of the compressed air measured by the pressure gauge 29 drops to the predetermined threshold value P3, as in the first fully open liquid removal step. The process shifts to the third partial open deliquescent step. The third partially open liquid removal step corresponds to the first partially open liquid removal step according to the present invention.

In the third partially open liquid removal step, as shown in FIG. 8B, the discharge device 33 opens one solenoid valve V6 so that the filtrate and air can be discharged from the 16th to 20th filter chambers 5. 1 Control to the partially open state. In this step, air and the filtrate cannot be discharged from the sufficiently deflated 1st to 15th filter chambers 5, so that the pressure of the compressed air temporarily increases as shown in FIG. However, also in the third partial open deliquescent step, the deliquescent is performed in the 16th to 20th filter chambers 5 and the filter substance 60 dries, so that the air permeability of the filter substance 60 is gradually improved. , The pressure of compressed air decreases. Then, the control panel 50 closes the closed solenoid valves V3 to 5 when the pressure of the compressed air measured by the pressure gauge 29 drops to the predetermined threshold value P3, as in the first fully open liquid removal step. , Move to the second fully open deliquescent step.

In the second fully open liquid removal step, similarly to the first fully open liquid removal step, compressed air permeates the filter cloth 4 in all the filter chambers 5 and is discharged from the discharge port 31. The second fully open deliquescent step is for completely discharging a trace amount of liquid component that was not discharged from the filter chamber 5 in the steps up to the third partially open filtration step. When the second fully open liquid removal step is executed for a certain period of time, the control panel 50 closes the solenoid valve V2 of the air supply pipe 24 of the supply device 20 and stops the supply of compressed air from the supply port 18 to the filter chamber 5. Then, the liquid removal process is completed.

As described above, in the liquid removal step, the solenoid valves V3 to V5 are closed stepwise to make it impossible to discharge the compressed air from the filter chamber 5 on the fixed end side that has been sufficiently drained, so that the liquid is removed. It is possible to continue to supply compressed air having a relatively high pressure to the filter chamber 5 on the insufficient movable end side. As described above, in this embodiment, although a relatively large number of filter plates 3 are laminated, even after the filter chamber 5 on the fixed end side is sufficiently deliquesed, it is compared with the filter chamber 5 on the movable end side. Since compressed air with a particularly high pressure can be supplied, the deliquescent process can be completed in a short time, and there is a possibility that the deliquescent process may be completed with insufficient deliquescent of the filter chamber 5 on the movable end side. Can be reduced.

Further, in this embodiment, the pressure of the compressed air supplied to the supply port 18 in the liquid removal step is measured by the pressure gauge 29, and the filter chamber 5 on the fixed end side is sufficiently removed based on the measured value of the pressure. Since each process is switched at the timing of liquidation, the liquid removal process can be performed efficiently.

The plate opening step is a step of converting the filter press main body 2 from the closed plate state to the open plate state, and discharging the dried filter substance (cake) 61 from the filter chamber 5. Specifically, in the plate opening process, the control panel 50 releases the tightening of the filter press main body 2 by operating the hydraulic pump 11 and moving the end plate 16b on the movable end side by the hydraulic cylinder 10. Convert to the open plate state. Then, the opening / closing motor 9 is operated, the filter plates 3 are separated from each other by the opening / closing mechanism 8 to open the filter chamber 5, and the filtered substance (cake) 61 inside the filter chamber 5 is dropped into the cake collecting unit 38. Further, in the plate opening step, the control panel 50 vibrates the filter cloth 4 by the vibrating device 14 to drop the filter substance 61 adhering to the filter cloth 4 onto the cake collecting unit 38.

As described above, the control panel 50 filters the liquid to be treated by executing a series of steps from the plate closing step to the plate opening step, and removes the filtered muddy filter substance (sludge) 60. Then, the dried filtered substance (cake) 61 is discharged to the cake collecting section 38 below the filter chamber 5 and collected. Then, the control panel 50 continuously filters the liquid to be processed by repeating a series of steps from the plate closing step to the plate opening step.

The filter press of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, 19 filter plates 3 are laminated, but the number of laminated filter plates 3 can be changed as appropriate. Further, the above embodiment is a single filter press in which a filter frame is not sandwiched between the filter plates 3 and 3, but the present invention is a double filter press in which a filter frame is interposed between the filter plates. Is also applicable.

Further, in the above-mentioned example, whether or not the filtrate and air can be discharged can be controlled in units of 5 to 6 filter chambers, but in the present invention, the discharge of filtrate and air can be controlled in units of 1 filter chamber. But it may be. Further, in the above-described embodiment, the filter cloth 4 is used as the filter sheet, but the filter press according to the present invention includes a filter paper.

Further, in the filtration step according to the above embodiment, each step is switched based on the pressure of the liquid to be treated measured by the pressure gauge 29, but the switching of each step in the filtration step is filtered into the filter chamber 5. Since it may be performed at the timing when the substance is accumulated to some extent, each process may be switched at the timing when the supply time or the supply amount of the liquid to be treated reaches a predetermined value, not limited to the pressure of the liquid to be treated. Good. Similarly, in the liquid removal step according to the above embodiment, each step is switched based on the pressure of the compressed air measured by the pressure gauge 29, but the switching of each step in the liquid removal step is on the fixed end side. Since it is sufficient to perform the operation at the timing when the filter chamber 5 of the above is sufficiently deliquesed, each process should be switched at the timing when the supply time and the supply amount of the compressed air reach a predetermined value, not limited to the pressure of the compressed air. It may be.

1 Filter press 2 Filter press body 3 Filter plate 4 Filter cloth (filter sheet)
5 Filter chamber 7 Switchgear 18 Supply port 20 Supply device 29 Pressure gauge (air pressure measuring means)
31 Discharge port 33 Discharge device 35 Individual discharge pipe (discharge pipe)
36 Intermediate discharge pipe (discharge pipe)
37 Overall discharge pipe (discharge pipe)
45 Communication port 50 Control panel (control device)
60 Filter material (sludge)
61 Filtered material (cake)
V3 to V6 solenoid valve (on-off valve)

Claims (7)

A filter press main body in which a plurality of filter plates are laminated with a filtration sheet sandwiched between them to form a filter chamber between adjacent filter plates.
A filter press including a closed plate state in which the filter plates are tightened in the stacking direction and an opening / closing device for converting the filter plate into an open plate state in which the filter chambers can be opened by separating the adjacent filter plates from each other. There,
The filter press body
A supply port formed on one end side of the filter plate in the stacking direction and communicating with the filter chamber on the one end side.
A communication port that penetrates the filter plate in the thickness direction and communicates with each other through the filter chambers formed on both sides of the filter plate.
It is provided with a plurality of outlets for discharging the filtrate and air in the filter chamber to the outside in communication with the filter chamber.
A supply device capable of selectively press-fitting the liquid to be treated and air from the supply port into the filter chamber on one end side,
An discharge device including a discharge pipe for drawing out the filtrate and air from each of the discharge ports, and an on-off valve capable of opening and closing the discharge pipe.
A control device for controlling the switchgear, the supply device, and the discharge device is provided.
The control device is
A plate closing step of converting the filter press main body from the open plate state to the closed plate state by the switchgear.
A filtration step in which the liquid to be treated is press-fitted into the filter chamber from the supply port by the supply device, filtered by a filtration sheet, and the filtrate that has passed through the filtration sheet is discharged from the discharge port by the discharge device.
A deliquesing step of press-fitting air from the supply port into the filter chamber by the supply device and discharging the liquid component in the filter chamber together with the air from the discharge port by the discharge device.
The opening / closing device sequentially executes a plate opening step of converting the filter press main body from the closed plate state to the open plate state.
The discharge device can be opened and closed by opening and closing the on-off valve.
A fully open state in which the filtrate and air can be discharged from all the filter chambers.
It is possible to switch to at least two states, that is, a first partially open state in which the filtrate and air cannot be discharged from the one end side in a predetermined number of the filter chambers and the filtrate and air can be discharged in the remaining filter chambers.
The control device is used in the liquid removal step.
The first fully open deliquescent step of controlling the discharge device to the fully open state and supplying air from the supply port, and
After the first fully open liquid removal step, the discharge device is controlled to the first partially open state, and the first partially open liquid removal step of supplying air from the supply port is executed. Filter press. A filter press main body in which a plurality of filter plates are laminated with a filtration sheet sandwiched between them to form a filter chamber between adjacent filter plates.
A filter press including a closed plate state in which the filter plates are tightened in the stacking direction and an opening / closing device for converting the filter plate into an open plate state in which the filter chambers can be opened by separating the adjacent filter plates from each other. There,
The filter press body
A supply port formed on one end side of the filter plate in the stacking direction and communicating with the filter chamber on the one end side.
A communication port that penetrates the filter plate in the thickness direction and communicates with each other through the filter chambers formed on both sides of the filter plate.
It is provided with a plurality of outlets for discharging the filtrate and air in the filter chamber to the outside in communication with the filter chamber.
A supply device capable of selectively press-fitting the liquid to be treated and air from the supply port into the filter chamber on one end side,
An discharge device including a discharge pipe for drawing out the filtrate and air from each of the discharge ports, and an on-off valve capable of opening and closing the discharge pipe.
A control device for controlling the switchgear, the supply device, and the discharge device is provided.
The control device is
A plate closing step of converting the filter press main body from the open plate state to the closed plate state by the switchgear.
A filtration step in which the liquid to be treated is press-fitted into the filter chamber from the supply port by the supply device, filtered by a filtration sheet, and the filtrate that has passed through the filtration sheet is discharged from the discharge port by the discharge device.
A deliquesing step of press-fitting air from the supply port into the filter chamber by the supply device and discharging the liquid component in the filter chamber together with the air from the discharge port by the discharge device.
The opening / closing device sequentially executes a plate opening step of converting the filter press main body from the closed plate state to the open plate state.
The discharge device can be opened and closed by opening and closing the on-off valve.
A fully open state in which the filtrate and air can be discharged from all the filter chambers.
It is possible to switch to at least two states, that is, a first partially open state in which the filtrate and air cannot be discharged from the one end side in a predetermined number of the filter chambers and the filtrate and air can be discharged in the remaining filter chambers.
The control device is used in the filtration step.
The first partially open filtration step of controlling the discharge device to the first partially open state and supplying the liquid to be processed from the supply port,
A filter press characterized in that after the first partially open filtration step, the discharge device is controlled to be in a fully open state, and a fully open filtration step of supplying a liquid to be processed from the supply port is executed. The supply device includes an air pressure measuring means capable of measuring the pressure of air press-fitted into the supply port.
The discharge device can be switched to a fully closed state in which the filtrate and air cannot be discharged in all the filter chambers by opening and closing the on-off valve.
The control device is
After the plate closing step and before the filtration step, a seal confirmation step of press-fitting air from the supply port into the filter chamber by the supply device in a state where the discharge device is controlled to a fully closed state is performed. Run and
The filter press according to claim 1 or 2, wherein in the seal confirmation step, an error is determined when the measured value of the air pressure measuring means does not reach a specified value. The supply device includes an air pressure measuring means capable of measuring the pressure of air press-fitted into the supply port.
The control device is characterized in that the first fully open liquid removal step is terminated when the measured value of the air pressure measuring means drops to a predetermined value during the first fully open liquid removal step. The filter press according to claim 1. The filter press according to claim 1, wherein the control device ends the first fully open liquid removal process when a predetermined time has elapsed from the start of the first fully open liquid removal process. .. By opening and closing the on-off valve, the discharge device is in a second partially open state in which the filtrate and air cannot be discharged from the one end side in a predetermined number of filter chambers, and the filtrate and air can be discharged in the remaining filter chambers. Switchable,
The number of the filter chambers in which the filtrate and air cannot be discharged in the second partially open state is smaller than the number of the filter chambers in which the filtrate and air cannot be discharged in the first partially open state.
The control device is used in the liquid removal step.
After the first fully open liquid removal step and before the first partially open liquid removal step, the discharge device is controlled to the second partially open state to supply air from the supply port. The filter press according to any one of claims 1, 4, and 5, wherein a second partially open deliquessing step is performed. The claim is characterized in that, at the end of the liquid removal step, the control device controls the discharge device to the fully open state and executes a second fully open liquid removal step of supplying air from the supply port. Item 1. The filter press according to any one of claims 4 to 6.

Images