JPH057709A - Filter press and filtration method of the same - Google Patents

Abstract

PURPOSE:To provide a filter press and a filtration method of the filter press which is able to prevent the leakage of original liquid in advance, to detect the inability of filtration operation in advance, to prevent the unprepared prolongation of filtration operation time, and to conduct filtration operation smoothly. CONSTITUTION:In a previous stage before starting filtration operation, the first fluid is supplied to each filtration chamber 16 to judge whether it is possible to maintain pressure within a specified range for a specified time. If the judgement is positive, the filtration is carried out by supplying original liquid after the discharge of the first fluid. On the other hand, if the judgement is negative, the cause is elucidated by the additional fastening of filter plates 14 or by the disassembly of the filter plates 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter press for confirming a sealed state of each filter chamber and then supplying a stock solution into each filter chamber for filtration, and a filtering method in the filter press.

[0002]

2. Description of the Related Art Conventionally, in filtration work, an approximate filter plate tightening pressure is usually set in advance and the filter plate is tightened.
The stock solution is supplied into the filter press body at a constant pump pressure. Therefore, even if there is a difference in the tightening pressure required for each filtration, whether or not the set tightening pressure is sufficient can be known only after shifting to the stock solution supply process. If the tightening pressure of the filter plate is insufficient, the filter plate is retightened again.

[0003]

However, in the above structure, when the filter plates are retightened, leakage of the stock solution or the like has already started between the filter plates. There is. In addition, if foreign matter such as cake is caught between the frames between adjacent filter plates, or if the filter plate is tightened with a part of the filter cloth folded in, liquid leakage will stop no matter how high the tightening pressure is. As a result, there is a problem in that the filtration work becomes impossible and the filtration time becomes carelessly long.

[0004] Therefore, the inventor of the present invention creates a solution that prevents the leakage of the undiluted solution from between the filter plates prior to the filtering operation, and then supplies the undiluted solution to the main body of the filter press to smoothly carry out the filtration. Came to.

The reason why the method of preventing the leakage of the stock solution prior to the filtration work has not been adopted in the filter press main body in which a large number of filtration chambers are arranged as pressure vessels is considered as follows. The first reason is that the fluid such as the undiluted solution supplied from the eyes of the filter cloth sandwiched between the filter plates generally leaks. Therefore, usually, the tightening pressure is set appropriately beforehand. It is said that the tightening pressure should be adjusted after tightening. The second reason is that, in order to reduce the leakage of the stock solution as much as possible, the tightening surface (frame surface) of the filter cloth may be sealed with an adhesive or a film-like material and the filter plate may be tightened. thing. The third reason is that it is sufficient to engrave a groove continuously and fit a sealing material all around the frame surface of the filter plate. The fourth reason is that it is sufficient to repeat the tightening operation after removing the foreign matter that has been bitten. Considering these reasons, in each of the above-mentioned operations, the basic idea was to tighten the filter plate with a preset tightening pressure, and to re-tighten the filter plate if this is still insufficient.

Therefore, an object of the present invention is to solve the above-mentioned problems by preventing leakage of the stock solution in advance, and by detecting in advance that the filtration operation becomes impossible, and carelessly performing it. It is an object of the present invention to provide a filter press and a filtering method in the filter press that can smoothly perform the filtering work without increasing the filtering work time.

[0007]

In order to achieve the above object, the present invention is constructed so that it is checked before the filtration operation whether there is any liquid leakage and then the filtration is performed.

That is, in the filtering method in the filter press according to the present invention, a large number of filter plates are arranged, a filter cloth is sandwiched between the filter plates, and the filter is tightened by a tightening device to perform filtration. After tightening the filter plate,
A first step of closing a discharge passage for discharging a first fluid for detecting liquid leakage from the inside of the filter press body to the outside of the filter press body, and supplying the first fluid from outside the filter press body into the filter press body after the first step And a second step of supplying the first fluid into the filter chambers formed between the filter plates from the outside of the filter press body to fill the filter chambers with the first fluid. After the process, the first
A third step of measuring the pressure in the filter press main body on a supply passage for supplying a fluid, maintaining the pressure within a predetermined range for a predetermined time, and discharging the first fluid from the discharge passage; A fourth step in which the undiluted solution is supplied into each filter chamber of the filter press body after the third step to advance the filtration;
When the pressure is not maintained within the predetermined range for the predetermined time in the third step, the filter plate is retightened without proceeding to the fourth step, and then the process proceeds to the third step, or the filtration is performed. The fifth step is to open the frame of the plate, solve the liquid leakage, tighten the filter plate again, and then proceed to the first step.

In the above structure, the filter plate may include a pressing plate having a pressing film.

In the filter press according to the present invention, a large number of filter plates are arranged, a filter cloth is sandwiched between the filter plates and tightened by a tightening device, and then the stock solution is fed between the filter plates by a stock solution supply device. In a filter press that supplies air into a formed filter chamber for filtration, a supply passage for supplying a first fluid for detecting liquid leakage from outside the filter press body into the filter press body, and from inside the filter press body to outside the filter press body A discharge passage for discharging the first fluid, a pressure measuring member for measuring the pressure in the filter press body on the supply passage for supplying the first fluid, a first opening / closing valve for opening and closing the supply passage, and the discharge A second on-off valve that opens and closes the passage,
A first fluid supply device for supplying the first fluid into the filter press body, and further, after tightening the filter plate, the discharge passage is closed by the second opening / closing valve while the supply passage is closed by the first passage. A first opening / closing valve is opened, and the first fluid is supplied to the filter chambers inside the filter press body from the outside of the filter press body by the first fluid supply device to fill each filter chamber with the first fluid. A comparison for determining whether or not the pressure is kept within a predetermined range for a predetermined time when the pressure in the filter press body is measured by the fluid filling means and the supply passage for supplying the first fluid with the pressure measuring member. Means and the comparing means determine that the pressure has been maintained within a predetermined range for a predetermined time, and then open the second opening / closing valve to discharge the first fluid from the discharge passage. A stage, and the start of filtration means to advance the filtration is supplied to the respective filter chamber of the filter press body stock solution by the solution feed device after discharging the first fluid,
When it is judged by the comparison means that the pressure is not kept within the predetermined range within the predetermined time, the filter plate is retightened or the filter plate is unfastened without operating the first fluid discharge means. And a filter plate tightening pressure adjusting means for opening the filter plate.

In the above structure, the filter plate may include a press filter plate having a press film.

[0012]

According to the structure of the present invention, by confirming the liquid leakage at the stage before starting the filtering operation, the leakage of the undiluted solution or the like from between the filter plates can be effectively reduced in the subsequent filtering operation. be able to. In other words, it is possible to prevent the stock solution from leaking in advance, detect in advance that the filtration operation becomes impossible, and prevent the filtration operation time from being unnecessarily lengthened, thus facilitating the filtration operation. Can be done. Further, it is not necessary to adjust the tightening many times in order to prevent leakage of the stock solution, and the filtration time is not unnecessarily lengthened. Further, the first fluid leaks out at the location where the filter plate is not properly tightened, so that it is possible to immediately recognize the number of the filter plate and the filter plate that are not properly tightened. It is also possible to detect whether the tightening failure is large or small before the stock solution is supplied to judge whether or not to continue the filtration process.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
It will be described in detail based on.

FIG. 1 is a schematic view of a filter press body of a filter press according to this embodiment, and a front view of one filter plate 14 is shown in the middle of a plurality of arrayed filter plates 14 ,. FIG. 2 is an explanatory diagram showing the supply and discharge paths of the liquid.

In FIG. 1, a pair of side beams 17, 17 is provided between the fixed plate 12 of the front stand and the rear stand 20.
, And filter plates 14, ..., 14 are arranged along the side beams 17, 17 so as to be movable back and forth. A filter cloth 15 is arranged between the filter plates,
The movable plate 11 is arranged behind the rearmost portion of the filter plate 14, and the movable plate 11 is advanced by driving the tightening device 13 of the rear stand 20 to tighten the filter plates 14 ,. At the same time, when the movable plate 11 is retracted, the filter plates 14, ..., 14
The tightening of is to be released.

A stock solution hole 10 is formed at the center of each filter plate 14, and a supply pipe 1 for supplying a first fluid or a second fluid, that is, a stock solution is connected to the stock solution hole 10. A first fluid supply device 21 for supplying a first fluid and a stock solution supply device 2 for supplying a stock solution to the supply pipe 1.
2 and are connected. In order to prevent the leakage of the undiluted solution from the space between the filter plates, the first fluid is filtered in the filter chamber 16 prior to the filtering operation.
It is a fluid to be supplied inside, and compressed air, water, nitrogen, etc. are preferable. Ear portions are formed so as to project at the corner portions on both sides of each filter plate 14, and the fluid discharge pipes 2, 2 are formed at the upper two ear portions.
A through hole to which 5 is connected is formed. Through holes to which the fluid discharge pipes 3 and 4 are connected are formed in the lower two ears. One of these discharge pipes 2, 3, 4, 5 can be used for discharging the first fluid, and the other three discharge pipes can be used for collecting the filtrate. A supply valve 6 for controlling the supply of compressed air or a stock solution is connected to the supply pipe 1, and the supply valve 6 and the filter plates 14, ..., 1 are connected.
A pressure gauge 9 for measuring the pressure inside the filter press main body is connected between the undiluted solution holes 4 ,. Further, as shown in FIG. 2, a discharge valve 7 is connected to a discharge pipe 18 in which the discharge pipes 2 and 5 are integrated, and a discharge valve 8 is connected to a discharge pipe 19 in which the discharge pipes 3 and 4 are integrated. Are connected.

Further, as shown in FIG. 3, the central control unit 2
3 controls the tightening device 13, the supply valve 6, the discharge valves 7 and 8, the first fluid supply device 21, and the stock solution supply device 22 and receives a pressure signal from the pressure gauge 9. There is.

When carrying out the filtration operation in the above-mentioned structure, first, as shown in FIG. 4, the discharge valves 7 and 8 of the discharge pipe are closed and the supply valve 6 is opened under the control of the central control unit 23.
The movable plate 11 is moved forward by the tightening device 13 to move the filter plate 14 ,.
Tighten 14 to the fixing plate 12 side (step # 1). Then, the first fluid supply device 21 is driven to supply the first fluid for confirming liquid leakage, for example, compressed air from the fixed plate 12 side through the supply pipe 1 into the filter press body (step #
2). The compressed air sequentially passes through the stock solution holes 10 of each filter plate 14, and is supplied into each filter chamber so that the filter cloth 15 covering the filter surface of each filter plate 14 is pressed against the filter floor surface. At this time,
The pressure of the first fluid held in the filter chamber is measured by the pressure gauge 9 in the middle of the supply pipe 1 (step # 3), and the central controller 23 determines whether or not the pressure within a predetermined range can be maintained for a predetermined time. (Step # 4). The pressure in the above predetermined range is
Not only does it mean any predetermined pressure value, but it may be a predetermined range having a certain allowable width. When the pressure in the predetermined range cannot be maintained, it is judged whether or not it can be dealt with by further tightening the filter plate 14 (step # 8). If it is possible, the filter plate 14 is further tightened ( Step # 10), perform pressure measurement again (Step #
3). If the filter plate 14 cannot be retightened, for example, if the filter cloth 15 partially bent or a foreign substance is caught between the filter plates to cause liquid leakage, the filter plate is not retightened. After the plate 14 is opened (step # 9), the filter cloth 15 is bent and foreign matter is removed, and then the filter plate 14 is tightened again from step # 1 and the same operation as above is performed. . On the other hand, when the inside of the filter press body can be maintained at a predetermined pressure, the discharge valves 7 and 8 are released to discharge the compressed air from the discharge pipes 2, 3, 4, and 5 to the outside of the filter press body (step # 5). ). When the compressed air has been exhausted, the stock solution supply pump (not shown)
Liquid supply device 2 located outside the main body of the filter press
As the stock solution, for example, treated wastewater after chemical production is pushed into the filter press main body from 2 with a predetermined pressing pressure so as to fill the inside of each filter chamber 16 from the stock solution holes 10 of each filter plate 14 in sequence (step # 6). After that, the filtering operation is continued, and after reaching the filtering limit and opening the filter plate 14 and discharging the cake (step # 7), the filtering operation is ended.

A specific example will be shown below. here,
The size of the filter plate is, for example, 1 m ² , and the number of filter plates is, for example, 50. Compressed air as the first fluid is supplied at a supply pressure of 7 kg / m ² for 3 minutes. On the other hand, the second fluid, that is, the treated waste water after chemical production as the stock solution is supplied at a supply pressure of 4 kg / m ² and the filtration time is 30 minutes.

(First Example) At the time of filtration work, first, the discharge valves 7 and 8 of the discharge pipe are closed, the supply valve 6 is opened, and the movable plate 11 is advanced by the tightening device 13 to move the filter plates 14, ..., 14 Fixing plate 12
Tighten to the side. Next, compressed air is supplied into the filter press main body from the fixed plate 12 side through the supply pipe 1. The compressed air sequentially passes through the stock solution holes 10 of each filter plate 14, and is supplied into each filter chamber so that the filter cloth 15 covering the filter surface of each filter plate 14 is pressed against the filter floor surface. At this time, the pressure gauge 9 in the middle of the supply pipe 1 dropped to 7 kg / m ² and then slightly descended to maintain 6 kg / m ² . After 3 minutes, the discharge valves 7 and 8 were opened to discharge the compressed air from the discharge pipes 2, 3, 4, and 5 to the outside of the filter press body. When the discharge of the compressed air is completed, the stock solution supply pump (not shown) subsequently operates to push the treated wastewater after manufacturing the chemicals as the stock solution into the filter press body from the stock solution supply device 22 outside the filter press body. It was pushed in at 4 kg / m ² and successively filled the inside of each filter chamber 16 from the stock solution hole 10 of each filter plate 14. Filter plate 14 and filter plate 1
There was no leakage from 4th. Thereafter, the filtration was continued, the filter plate 14 was opened up to the filtration limit, and after the cake was discharged, the filtration was completed.

(Second Example) Although compressed air was used as the first fluid in the above-mentioned filtration method, the case of using water will be described.

Water was supplied as the first fluid at a supply pressure of 5 kg / m ² using the same filter press as above, and after holding for 5 minutes, the second fluid was supplied.
As the fluid, the same stock solution as in the previous example was filtered at a supply pressure of 3.5 kg / m ² and a filtration time of 45 minutes. There was no liquid leakage from the beginning of filtration.

(Third Example) Next, as a third example, the first
In the example, while the supply valve 6 and the discharge valve 8 were closed, the discharge valve 7 was opened and compressed air was introduced into the filter press main body from the discharge pipes 2 and 5. As a result of subsequent filtration in the same manner,
There was no leakage from the beginning of filtration.

Comparative Example On the other hand, as a comparative example,
The same filter press as in the above-mentioned first example was used to drive the same treated wastewater after chemical production at a supply pressure of 4.1 kg / m ² for filtration.
At the initial stage of filtration, liquid leaked from between several filter plates through the filter cloth, so the filter plate clamping pressure was adjusted by additional tightening. The filtration time was 35 minutes, including about 5 minutes required for retightening adjustment.

According to the above-mentioned embodiment, by confirming the liquid leakage at the stage before starting the filtering operation, it is possible to effectively reduce the leakage of the undiluted solution or the like from between the filter plates in the subsequent filtering operation. . In other words, it is possible to prevent the stock solution from leaking in advance, detect in advance that the filtration operation becomes impossible, and prevent the filtration operation time from being unnecessarily lengthened, thus facilitating the filtration operation. Can be done. Further, it is not necessary to adjust the tightening many times in order to prevent leakage of the stock solution, and the filtration time is not unnecessarily lengthened. Further, the first fluid such as compressed air leaks out at a location where the filter plate 14 is not properly tightened, so that it is possible to immediately know the number of the filter plate 14 and the filter plate 14 which are not properly tightened. . It is also possible to detect whether the tightening failure is large or small before the stock solution is supplied to judge whether or not to continue the filtration process.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

For example, the present invention can be applied to both a single filter press and a double filter press. Also,
By performing the filtration work after the liquid leakage prevention process, the pump pressure is increased and the raw liquid is driven into the filter press body at high pressure (5 to 15 kg / m ² ) to prevent liquid leakage from the beginning of filtration and to improve filtration efficiency. It is also effective when trying to increase.

The filter press body and the piping system connected thereto are not limited to those in the above embodiment, but the positions of the undiluted solution holes in the filter plate 14, the positions of the fluid discharge holes for the filtrate and the like, and the piping connected to these The design can be changed as desired.

Further, as another embodiment, when the filter plate 14 is a squeezing filter plate having a squeezing membrane, the first fluid is introduced from the undiluted solution hole 10 to check the liquid leakage of the filter chamber, that is, the frame of the filter plate. After confirming the sealing property between the part covered with the squeeze film and the part covered with the squeeze film of the pair of filter cloths and the filter plate, when draining the first fluid, the discharge pipes 2, 3, It is preferable to draw out from the discharge pipes out of the lines 4 and 5 except the pipe line leading to the compressed fluid supply source. Further, the position of the undiluted solution hole 10 may be located inside or outside near the frame of the filter plate. In this embodiment as well, it is possible to obtain substantially the same effects as the previous embodiment, but even if the conduit leading to the compressed fluid supply source for the compressed membrane is opened when the first fluid is supplied, the No fluid leaks out. If the first fluid leaks from the conduit, there is a rupture hole in the squeeze membrane, and the first fluid leaks from the rupture hole. That is, the rupture of the squeeze membrane can be confirmed at the same time as the work of supplying the first fluid and confirming the liquid leakage. The first fluid is not limited to the one supplied from the undiluted solution hole 10, and the one functioning as a filtrate recovery hole in the discharge pipe may be used to supply the first fluid from the discharge pipe to the filter chamber. . 1st fluid undiluted liquid hole 10
If you press the compressed fluid from one of the discharge pipes that functions as a compressed fluid supply pipe for the compressed film instead of inserting it from the inside, check that the compressed film is broken and that the filter chamber is sealed between the adjacent filter plates through the compressed film. You can check whether it is fastened to. However, in this case, the squeeze membrane swells and expands the squeeze membrane more than when the cake is squeezed toward the filter chamber space, but if the squeeze membrane has good restoration properties, the squeeze membrane will not be damaged at all. There is no. However, since this elongation is too large in a normal rubber film, it is necessary to sufficiently consider the degree of expansion. Also, be careful as a compressed film made of polypropylene may grow during repeated use. Further, when the compressed fluid is introduced into the filter chamber through the discharge pipe, the hole of the filter plate connected to the discharge pipe is small. Therefore, be careful when introducing the first fluid, which is the high-pressure compressed fluid, through this hole. Therefore, it is preferable to insert from the stock solution hole as much as possible.

Further, in the present invention, whether or not the pressure is maintained within a predetermined range is automatically judged by the central control unit 23 by a signal from the pressure gauge 9, but in a simple type filter press. The operator may directly judge the pressure gauge 9 to make a determination, and manually drive the filter plate tightening device, the valve, and the supplying device.

[Brief description of drawings]

FIG. 1 is a schematic side view of a filter press body of a filter press according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the piping of the filter press body shown in FIG.

FIG. 3 is a schematic view showing a filter press according to the above embodiment.

FIG. 4 is an explanatory diagram for explaining an operation procedure of the filter press according to the above embodiment.

[Explanation of symbols]

1 ... Supply pipe, 2, 3, 4, 5 ... Discharge pipe, 7, 8 ... Discharge valve, 9 ... Pressure gauge, 10 ... Undiluted solution hole, 11 ... Movable plate, 12 ...
Fixed plate, 13 ... Tightening device, 14 ... Filter plate, 15 ... Filter cloth, 1
6 ... Filter chamber, 17 ... Side beam, 18, 19 ... Discharge pipe,
20 ... Rear stand, 21 ... 1st fluid supply apparatus, 22 ... Undiluted solution supply apparatus, 23 ... Central control apparatus.

Claims (4)

[Claims] 1. A filtration method in a filter press, wherein a large number of filter plates (14) are arranged, a filter cloth (15) is sandwiched between the filter plates and tightened by a tightening device (13) to perform filtration. After tightening, the first step of closing the discharge passages (2, 3, 4, 5) for discharging the first fluid for fluid leak detection from the inside of the filter press body to the outside of the filter press body, and the inside of the filter press body after the first step To the supply passage (1,
2, 3, 4, 5) are opened and the first fluid is supplied from the outside of the filter press main body into the filter chambers (16) formed between the filter plates so that the filter chambers (16) are connected to the first filter chamber (16). A second step of filling with a fluid, and measuring the pressure in the filter press body on the supply passage for supplying the first fluid after the second step, and after the pressure is kept within a predetermined range for a predetermined time, A third step of discharging the first fluid from the discharge passage, a fourth step of supplying the stock solution into each of the filter chambers (16) of the filter press body to promote filtration after the third step, and the third step When the pressure is not kept within the predetermined range for the predetermined time in the step, the filter plate (14) is retightened without proceeding to the fourth step, and then proceeds to the third step, or the filtration step is performed. Open the frame of the plate (14) to solve the liquid leakage and tighten the filter plate (14) again. Filtration method in the filter press, characterized in that as provided in the fifth step, the process proceeds to the first step after performing the. 2. The filtration method in a filter press according to claim 1, wherein the filter plate (14) includes a press filter plate having a press film. 3. A plurality of filter plates (14) are arranged, a filter cloth (15) is sandwiched between the filter plates and tightened by a tightening device (13), and then the stock solution is filtered by a stock solution supply device (22). In a filter press for supplying water into a filter chamber formed between plates to perform filtration, supply passages (1, 2, 3, 3) for supplying a first fluid for fluid leakage detection from outside the filter press body into the filter press body.
4, 5), a discharge passage (2, 3, 4, 5) for discharging the first fluid from the inside of the filter press body to the outside of the filter press body, and a supply passage for supplying the first fluid. A pressure measuring member (9) for measuring the internal pressure, a first opening / closing valve (6) for opening / closing the supply passage, a second opening / closing valve (7, 8) for opening / closing the discharge passage, and the first fluid And a first fluid supply device (21) for supplying the exhaust gas to the inside of the filter press body, and further, after tightening the filter plate, connect the discharge passages (2, 3, 4, 5) to the second opening / closing valve (7). , 8) while the supply passages (1, 2, 3, 4, 5) are opened by the first opening / closing valve (6), and the first fluid supply device (21) is used to open the filter press main body. From the outside of the filter press body to the filter chamber (16), the first The first fluid filling means (23) for supplying the body to fill each of the filter chambers (16) with the first fluid, and the pressure inside the filter press body on the supply passage for supplying the first fluid, When measuring with the measuring member (9), the comparing means (23) for judging whether or not the pressure is kept within a predetermined range for a predetermined time, and the comparing means (23) keeps the pressure within a predetermined range for a predetermined time. After it is determined that the first fluid is retained, the second on-off valve (7, 8) is opened to allow the first fluid to flow through the discharge passage (2, 2).
First fluid discharging means (23) for discharging from 3, 4, 5)
A filter starting means (23) for discharging the first fluid and then supplying the stock solution into each of the filter chambers (16) of the filter press body by the stock solution supply device to advance the filtration; and the comparing means (23). When it is determined that the pressure is not kept within the predetermined range within the predetermined time by the method, the filter plate (14) is retightened or the filter plate (14) is operated without operating the first fluid discharge means (23). A filter press, comprising: a filter plate tightening pressure adjusting means (23) for releasing the tightening of (14) to open the filter plate (14). 4. A filter press according to claim 3, wherein the filter plate (14) comprises a press filter plate having a press membrane.