JP7245985B2 - Air blow method for filter press - Google Patents

Description

TECHNICAL FIELD The present invention relates to an air blow for a filter press, and more particularly to an air blow method for a filter press that supplies air through communication passages that communicate filter chambers.

In a filter press, as a technology for further reducing the water content of the cake squeezed by the diaphragm, an air blowing technology is known in which high-pressure air is used to entrain and remove moisture between cake particles, which is difficult to push out by mechanical compression pressure in the filtration chamber.

In Patent Document 1, an air supply pipe and a drainage pipe are connected to each filtration chamber of a filter press, and compressed air is evenly supplied to the filtration chamber through each air supply pipe to drain interstitial water remaining between particles. An air blow technique for discharging from a liquid tube is disclosed.

In addition, Patent Document 2 discloses a technique of blowing air in parallel to each filter chamber from a mud supply channel that supplies a stock solution in a center-feed filter press in which each filter chamber communicates at the center of the filter plate. .

JP-A-60-094109 Japanese Patent No. 5970357

A method of supplying compressed air by connecting an air supply pipe to a filter plate leading to each filtration chamber as in Patent Document 1, and a method of supplying compressed air to each filtration chamber through a mud supply channel as in Patent Document 2. This method can supply a sufficient amount of air to each filter chamber, and can push out interstitial water remaining between particles of the dehydrated cake.

However, the dehydrated cake in each filtration chamber slightly differs in the consolidation state and porosity of the solid matter. Compressed air is supplied to each filter chamber in parallel, forming water and air passages in the dehydrated cake while pushing out interstitial water. A large amount of compressed air flows into the filter chamber from the other filter chambers because the pressure resistance of the filter chamber with wide air gaps or many passages formed therein is low. As a result, the moisture content of the dehydrated cake produced in each filtration chamber becomes uneven, and a great deal of labor and expense is required for transportation and treatment of the dehydrated cake.

The present invention provides an air blow method for a filter press, in which high-pressure air is supplied from one side of a row of closed filter plates, and all filter chambers are air-blown in series through a communication passage that communicates the respective filter chambers. provide a way.

The present invention provides a filter press in which a plurality of filter plates are arranged in parallel to form a filter chamber between the filter plates, and in which an air blow step is performed by supplying high-pressure air after performing a filtration step in the filter chamber, the adjacent filter chambers are communicated. to form a high-pressure air passage in series, close the valves provided in the undiluted solution supply passage and the filtrate discharge passage, open the valves provided in the high-pressure air supply passage and the discharge passage, and then close the high-pressure air passage. High-pressure air is supplied from one side, interstitial water of the dehydrated cake in each filtration chamber is stored in the filtrate tank, and high-pressure air is discharged from the other side of the high-pressure air path, and after a predetermined time, the interstitial water stored in the filtrate tank is discharged to the outside. Since there is no increase or decrease in the amount of air supplied to the filter chamber due to variations in the compaction of the dehydrated cake, the entire amount of supplied air can be used for air blow without waste, making it possible to reduce the amount of supplied air.

If the high-pressure air supply path is a filtrate pipe that connects to the front end of the frontmost filtration chamber, or a communication path that connects the front end of the front filtration chamber and the front end of the filter plate row, the high-pressure air supply port is 1 or 1. This eliminates the need for air supply pipes to connect to each filter plate, reducing the number of parts.

If the discharge path of the high-pressure air passage is a filtrate pipe that connects to the rear end of the last-stage filtration chamber, or a communication passage that connects the rear-end of the last-stage filtration chamber and the row of filter plates, then the high-pressure air exhaust port is There is no need for exhaust pipes connected to each filter plate, and the number of parts can be reduced.

The filtrate tank is attached to the bottom of a pair of filter plates forming each filtration chamber on the rear end side, and is connected to a filtrate pipe. It can be temporarily stored in a liquid tank.

In addition, if the filtrate tank is connected to the filtrate pipe that discharges the filtrate from each filtration chamber, the interstitial water will be expelled from each filtration chamber by opening only the valve provided at the rear end of the filtration bed during air blow. can be temporarily stored in a common filtrate tank.

In the filter press air blowing method according to the present invention, high-pressure air communicates with each filtration chamber in series. The entire amount of supplied air can be used for air blowing to all the filtration chambers without waste, making it possible to produce a uniform dehydrated cake and reducing the possibility of cake peeling failure in the plate opening process.
In addition, since there is only one inlet for supplying high-pressure air to the row of filter plates, an air supply pipe connecting to each filter plate is not required, and the number of parts can be reduced.

1 is an overall flow chart according to the present invention; FIG. Similarly, it is sectional drawing of a filtration chamber. Similarly, it is sectional drawing of the filtration chamber at the time of an air blow process. Similarly, it is sectional drawing of the filtration chamber at the time of the air blow process of other Example 2. FIG.

FIG. 1 is an overall flow chart according to the present invention.
Only the dehydration mechanism of the filter press 1 is extracted, and the filter plate 2 configured to be freely movable back and forth is closed to form a filtration chamber 3, and the undiluted liquid containing water is supplied to perform solid-liquid separation. conduct.

A stock solution supply pipe 4 is connected to the front end (left side of the figure) of the filter plate row formed by closing the filter plates 2 , and the stock solution stored in the stock solution storage tank 5 is supplied to the filtration chamber 3 by the stock solution supply pump 6 . The undiluted solution is subjected to solid-liquid separation by pressure feeding by the undiluted solution supply pump 6 or by mechanical compression or the like. A separated liquid (filtrate) is discharged outside from a filtrate discharge pipe 8 via a filtrate pipe 7 connected to each filter plate.

A high-pressure air pipe 9 is connected to the filtrate pipe 7 , and high-pressure air is supplied from a high-pressure air supply source 10 through the high-pressure air pipe 9 into the filtration chamber 3 . High-pressure air is used to entrain and eliminate moisture between particles of the dehydrated cake, which is difficult to extrude by mechanical compression pressure, etc., thereby further reducing the moisture content. The high pressure air supply 10 can use known technology such as a compressor.

The high-pressure air supplied to the filtration chamber 3 flows into the filtrate pipe 7 together with interstitial water contained in the dehydrated cake, and is discharged to the outside from the filtrate discharge pipe 8 together with the filtrate.

The dehydrated cake, which has been completely dehydrated and has a low moisture content, is discharged outside by opening the row of filter plates.

FIG. 2 is a cross-sectional view of the filtering chamber.
A concave filter bed 11 is formed on the filter plate 2 , and a filter cloth 12 is stretched over the filter bed 11 to form a filter chamber 3 between the adjacent filter plates 2 , 2 . An undiluted solution supply channel 13 communicating with the filter plate 2 is provided above the filter plate 2 . The undiluted solution supply path 13 communicates with the undiluted solution supply pipe 4 at the front end of the row of filter plates.

The raw liquid is pressurized into the filter chamber 3 from the raw liquid supply pipe 4 and solid-liquid separated by the filter cloth 12 .
The separated filtrate is discharged to the filter bed 11 of the filter plate 2 , extracted from the filtrate discharge hole 15 provided below the filter bed 11 , and discharged to the filtrate tube 7 . The discharge holes 15 are provided in the front and rear filter beds 11 , 11 facing the filtration chamber 3 , respectively, and the filtrate pipe 7 is communicated with the discharge holes 15 .

Filtrate tanks 16 for temporarily storing the filtrate from the filtration chambers 3 are provided below the filter plates 2, respectively. The filtrate tank 16 is provided on the rear end side (the high-pressure air discharge side) of the pair of filter plates 2, 2 forming the filtration chamber 3. In this embodiment, the filtrate tank 16 is provided at the bottom of the filter plate 2. Attached. A filtrate pipe 7 is connected to the filtrate tank 16, and the temporarily stored filtrate is discharged to the filtrate pipe 7 as required. The other ends of the filtrate pipes 7 are connected to a filtrate discharge pipe 8 through which the filtrate is discharged to the outside.

A communication passage 17 is formed in the filter plate 2 to communicate between the adjacent filter chambers 3 , 3 . The communication path 17 penetrates the inside of the filter plate 2 and communicates from the opening provided in the filter bed 11 to the opening provided in the adjacent filter bed 11 at the shortest distance.

The high-pressure air pipe 9 is connected to the filter plate side of the valve V2 interposed in the filtrate pipe 7 on the front end side of the front end filter chamber 3, and when high-pressure air is supplied to the filter chamber 3 from the discharge hole 15, the continuous High-pressure air is supplied to each filter chamber 3 in series through the passage 17 . The high-pressure air that has flowed into the final filter chamber 3 is discharged from the discharge holes 15 formed in the filter bed 11 .

In this embodiment, the communication path 17 is formed linearly above the filter bed 11, but it may be formed in the center or below the filter bed 11. FIG. Moreover, as shown in FIG. 4, the upper and lower sides of the filtration chamber 3 may be alternately communicated with each other.

The open/closed state of each valve shown in FIG. 2 represents the state during the dehydration process.
As for the operation of the filter press 1, the air blowing process is started after the dehydration process (for example, at the time of pressurizing the undiluted solution). In addition, the mechanical pressing process is appropriately performed before and after the air blowing process as required.

In the dehydration process, all the valves V1, V2, V2r interposed in the raw liquid supply path and the filtrate discharge path are open, and the valve V3 interposed in the high pressure air supply path is closed.

In this embodiment, the undiluted solution supply pipe 4 is provided with a valve V1, each filtrate pipe 7 is provided with a valve V2, the rearmost filtrate pipe 7 is provided with a valve V2r, and the high-pressure air pipe 9 is provided with a valve V3. The opening and closing of the valve during the pressing process is substantially the same as that during the pressurization of the undiluted liquid, but the valve V1 interposed in the feed passage of the undiluted liquid is closed.

The undiluted liquid separated into solid and liquid in the filtration chamber 3 flows into the discharge hole 15 of the filter bed 11 and is discharged to the outside through the filtrate pipe 7 and the filtrate discharge channel 8 . Since all the valves V2 interposed in the filtrate pipe 7 are open, the filtrate is not stored in the filtrate tank 16.

FIG. 3 is a cross-sectional view of the filtration chamber during the air blowing process.
After the dehydration process of the undiluted solution is finished, the air blowing process is started.
In the air blowing process of this embodiment, the high-pressure air passages AL are formed in series by connecting the filtration chambers 3 in the row of filter plates with the communication passages 17, and high-pressure air is supplied from one side of the high-pressure air passages AL. While interstitial water of the dehydrated cake in each of the filtration chambers 3 is temporarily discharged to the filtrate tank 16, high pressure air is discharged from the other of the high pressure air passages AL.

In the air blowing process, the valve V1 interposed in the raw liquid supply path is closed, the valve V3 interposed in the high-pressure air supply path is opened, and the valve V2 interposed in the filtrate discharge path is closed. The valve V2r interposed in the filtrate pipe 7 provided on the rear end side of the filtration chamber 3 is opened.

That is, high-pressure air is supplied in series by using the filtrate pipes 7, 7 provided at the front end side of the frontmost filtration chamber 3 and at the rear end side of the rearmost filtration chamber 3 as high-pressure air supply pipes and discharge pipes, respectively. A high-pressure air passage AL is formed so as to pass through each of the filtration chambers 3.

The high-pressure air supply source 10 is operated to supply high-pressure air to the filter chamber 3 from the upstream side of the high-pressure air passage AL formed in series via the high-pressure air pipe 9 . High-pressure air flows into the front-stage filter chamber 3 through the filtrate pipe 7 and the discharge hole 15 provided at the front end of the row of filter plates.

The high-pressure air that has flowed into the filter chamber 3 winds along the concave portion of the filter bed 11 on the inflow side due to the resistance of the dehydrated cake in the filter chamber 3 . When the pressure is further increased by supplying high-pressure air, it flows into the gaps between the filter cloth 12 and the dehydrated cake.

The high-pressure air that has flowed into the dehydrated cake pushes interstitial water remaining between particles of the dehydrated cake to the filter bed 11 on the rear end side of the filtration chamber 3 . The interstitial water is sent from the discharge hole 15 to the filtrate tank 16 through the filtrate pipe 7 and is temporarily stored.

After that, the high-pressure air spreads along the filter bed 11 on the rear end side of the filtration chamber 3 and flows into the next filtration chamber through the communication passage 17 connecting the filtration chambers 3, and similarly the gaps in the dehydrated cake Water is pushed out to the filtrate tank 16 .

While sequentially pushing out the interstitial water of the dehydrated cake in the filtration chambers 3, the high-pressure air exiting the final filtration chamber 3 flows into the discharge holes 15 provided in the filter bed 11 on the rear end side of the filtration chamber 3, and the filtrate is discharged. The filtrate is discharged to the outside from the pipe 7 via the filtrate discharge pipe 8 .

After the air blow is completed at a predetermined timing, the valve V2 provided in the filtrate pipe 7 is opened to discharge interstitial water (filtrate) stored in the filtrate tank 16 to the outside. It should be noted that high-pressure air may be supplied when the water stored in the filtrate tank 16 is discharged.

In this embodiment, the high-pressure air pipe 9 is connected to the front end of the row of filter plates as a high-pressure air supply passage, but the high-pressure air pipe 9 may be connected to the rear end of the row of filter plates. In that case, a filtrate tank 16 is attached to the front end side of the pair of filter plates 2 , 2 forming the filter chamber 3 .

FIG. 4 is a cross-sectional view of the filtration chamber during the air blowing process of another embodiment 2. FIG.
In Example 2, a communication passage 17 communicating between the front end of the filter chamber 3 and the front end of the filter plate row and a communication passage 17 connecting the rear end of the filter plate row with the rearmost filter chamber 3 are provided. A high-pressure air pipe 9 is communicated with. The high-pressure air pipe 9 f on the front end side is connected to the high-pressure air supply source 10 , and the high-pressure air pipe 9 r on the rear end side is connected to the filtrate discharge pipe 8 .

Communicating passages 17 serving as high-pressure air supply passages are alternately communicated above and below the filtration chamber 3 toward the rear stage of the filtration chamber 3 . Since the supply port and the discharge port of the high-pressure air to the filter chamber 3 are separated, it exerts a wide action on the front surface of the dehydrated cake in the filter chamber 3 and efficiently pushes out interstitial water.

Filtrate pipes 7 are communicated with discharge holes 15 before and after discharging filtrate from each filtration chamber 3 , and each filtrate pipe 7 is connected to a common filtrate tank 18 . The temporarily stored filtrate is discharged to the outside through the filtrate discharge pipe 8 .

In the dehydration step, valves V1, V2 and V4 interposed in the raw solution supply path and filtrate discharge path are all opened, and valves V3 and V5 interposed in the high pressure air supply and discharge paths are closed.

After the dehydration process of the undiluted solution is finished, the air blowing process is started.
In the air blowing step, the valve V1 interposed in the raw liquid supply path is closed, and the valves V3 and V5 interposed in the high pressure air supply and discharge paths are opened. As for the valve V2 interposed in the filtrate discharge passage, only the valve V2r provided on the rear end side of the filtration bed 11 (high pressure air discharge side) is opened, and the rear end side of the filtration bed 11 (high pressure air discharge side) is opened. side) is closed. Also, the valve V4 provided on the filtrate discharge pipe 8 connected to the filtrate tank 18 is closed. That is, while extruding the interstitial water of the dehydrated cake in each of the filtration chambers 3 into the common filtrate tank 18, the filtrate pipes are connected to the transfer holes 15 communicating with the filter beds 11 on the rear end side of each of the filtration chambers 3. A high-pressure air passage AL is formed so that high-pressure air passes through the filter chambers 3 in series by opening only the valves V2r interposed in the filter chambers 3-7.

The high-pressure air supply source 10 is operated to supply high-pressure air to the filter chamber 3 from the front end side of the filter plate row, which is the supply channel, through the high-pressure air pipe 9f. High-pressure air flows into the foremost filter chamber 3 from a communication passage 17 provided at the front end of the row of filter plates.

The high-pressure air that has flowed into the filtration chamber 3 pushes interstitial water remaining between particles of the dehydrated cake to the filtration bed 11 on the rear end side of the filtration chamber 3 . The interstitial water is sent from the discharge hole 15 to the filtrate tank 18 through the filtrate pipe 7 .

After that, the high-pressure air flows from the front-stage filter chamber 3 through the communication passage 17 into the next-stage filter chamber 3 , and similarly pushes out interstitial water in the dehydrated cake to the filtrate tank 18 . At this time, since the communication passages 17 alternately communicate with the top and bottom of the filtration chamber 3, the dehydrated cake in the filtration chamber 3 is affected over a wide range, and the interstitial water is efficiently pushed out.

The high-pressure air that has passed through the final filter chamber 3 flows through the communication passage 17 into the high-pressure air pipe 9r, which is the discharge passage, and is discharged from the filtrate discharge pipe 8 to the outside.

The degree of opening of the valve V2r leading to the filtrate tank 18 may be adjusted according to the distance from the high-pressure air supply path. Also, a check valve may be used as the valve V2r.

After the air blow is completed at a predetermined timing, the valve V4 provided on the filtrate discharge pipe 8 is opened to discharge interstitial water (filtrate) stored in the filtrate tank 18 to the outside.

In Example 2, high-pressure air is supplied from the front end of the filter plate row and discharged from the rear end of the filter plate row. High pressure air may be discharged from the front end. At that time, the air blowing process is performed by opening only the valve V2f provided in the filtrate pipe 7 communicating with each filtration chamber 3, which is located away from the supply side of the high-pressure air.

Moreover, the supply path and discharge path of the high-pressure air path AL may be combined with those of Examples 1 and 2, and can be appropriately selected according to the specifications of the filter press and the properties of the stock solution.

In the air blowing method of the filter press according to the present invention, since the ventilation passages for high-pressure air are configured in series with each filtration chamber and the communication passage, the entire amount of supplied air can be used for air blowing without waste, and uniform dewatered cake can be produced. can be generated. Errors due to defective cake peeling in the plate opening process are reduced, and troubles in the subsequent process of processing the dehydrated cake are reduced. Therefore, in the treatment of water purification sludge, sewage sludge, industrial wastewater sludge, etc., where the dewatered cake is reduced to a low moisture content by air blowing, the properties of the dehydrated cake are stabilized and the time and effort of the post-treatment process can be reduced. becomes.

1 filter press 2 filter plate 3 filter chamber 7 filtrate tube 11 filter bed 16 filtrate tank 17 communication passage 18 filtrate tank AL high-pressure air paths V1, V2, V2r, V3, V4, V5 valves

Claims (7)

A plurality of filter plates (2 . In the filter press (1) that performs
Adjacent filtration chambers (3, 3) are communicated to form serial high-pressure air passages (AL),
Close the valves (V1, V2, V4) provided in the raw solution supply path and the filtrate discharge path,
After opening the valves (V2r, V3, V5) provided in the high-pressure air supply path and discharge path,
supplying high pressure air from one of the high pressure air passages (AL);
While storing the interstitial water of the dehydrated cake in each filtration chamber (3...) in the filtrate tank (16, 18),
discharging high pressure air from the other side of the high pressure air passage (AL);
An air blowing method for a filter press, characterized in that interstitial water stored in filtrate tanks (16, 18) is discharged to the outside after a predetermined period of time.
2. The air blowing method for a filter press according to claim 1, wherein the supply passage of said high-pressure air passage (AL) is a filtrate pipe (7) connected to the front end of the frontmost filter chamber (3).
2. The air blower of the filter press according to claim 1, wherein the supply passage of the high-pressure air passage (AL) is a communication passage (17) that communicates the front end of the filter chamber (3) with the front end of the row of filter plates. Method.
The air blow of the filter press according to claim 1, wherein the discharge path of the high-pressure air path (AL) is a filtrate pipe (7) connected to the rear end side of the last stage filtration chamber (3). Method.
2. The filter press according to claim 1, wherein the discharge passage of the high-pressure air passage (AL) is a communication passage (17) that communicates the last stage filter chamber (3) with the rear end of the row of filter plates. air blow method.
The filtrate tank (16) is attached to the bottom of the rear end side of the pair of filter plates (2, 2) forming each of the filtration chambers (3...), and is connected to the filtrate pipes (7...). The air blowing method for a filter press according to any one of claims 1 to 5, characterized by:
The filtrate tank (18) is connected to the filtrate pipes (7...) for discharging the filtrate from the filtration chambers (3...), and is provided on the rear end side of the filter bed (11) during air blowing. The air blowing method for a filter press according to any one of claims 1 to 5, characterized in that only the valve (V2r) is opened.

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