JP2010051910A - Anomaly detection method of filter press and filter press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of detecting slurry leakage from filter plates, the anomaly of a filter press, at an early stage, in the filter press including a reciprocating constant discharge pressure pump as a slurry feed pump. <P>SOLUTION: In the anomaly detection method of the filter press having the reciprocating constant discharge pressure pump as the slurry feed pump, the time required for one time slurry feeding immediately after the high pressure feeding of the slurry for each filtering work. When a ratio of T1/T2 of the feeding time T1 immediately after the high pressure feeding in the current filtering work to the feeding time T2 immediately after the high pressure feeding in the previous filtering work is equal to or less than the prescribed value which is less than 1, the slurry is determined to leak from filter plates. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an abnormality detection method for a filter press.

The filter press disclosed in Patent Document 1 is widely used for sludge treatment.
Japanese Examined Patent Publication No. 2-62285

In the filter press, a center plate having a slurry discharge hole and a pair of filter cloths are sandwiched between a pair of filter plates having drain holes and recesses, and the slurry is driven into the filter chamber formed by the recesses from the slurry discharge holes. Filter the slurry at Therefore, if the close contact between the filter plate and the center plate is insufficient, the slurry leaks from the filter chamber and cannot perform its original function.
The present invention relates to a filter press having a reciprocating constant discharge pressure pump as a slurry driving pump, a method for quickly detecting slurry leakage from a filter plate, which is abnormal in the filter press, and a slurry leak from a filter plate. It aims at providing the filter press which can be performed.

In order to solve the above-mentioned problem, in the present invention, there is provided an abnormality detection method for a filter press provided with a reciprocating constant discharge pressure pump as a slurry driving pump, which is driven once immediately after the start of high-pressure driving of slurry for each filtering operation. When the ratio T1 / T2 between the driving time T1 immediately after the start of high-pressure driving in the current filtering operation and the driving time T2 immediately after the start of high-pressure driving in the previous filtering operation is less than a predetermined value less than 1 And providing an abnormality detection method characterized in that it is judged that slurry is leaking from the filter plate.
When a reciprocating constant discharge pressure pump such as an air-driven diaphragm pump is used as a slurry driving pump, a slurry with a constant pressure is supplied to the filter chamber. Therefore, the slurry is supplied once depending on the flow resistance when the liquid is discharged from the filter chamber. The time required to drive the slurry increases or decreases. From the viewpoint of suppressing clogging of the filter cloth, a filter press generally performs low-pressure slurry driving at the start of slurry driving, and shifts to high-pressure driving after a predetermined time has elapsed. A change in the time of single implantation due to the presence or absence of leakage from the filter plate should be more noticeable when the high pressure is implanted than when the low pressure is implanted. Therefore, the time required for one implantation immediately after the start of the high-pressure implantation of the slurry is measured for each filtration operation, and the implantation time T1 immediately after the start of the high-pressure implantation in the current filtration operation and the implantation time immediately after the start of the high-pressure implantation in the previous filtration operation. By detecting that the slurry is leaking from the filter plate when the ratio T1 / T2 with T2 is less than a predetermined value less than 1, the filter press abnormality of the slurry leaking from the filter plate is quickly detected. Can do.

In a preferred aspect of the present invention, the reciprocating constant discharge pressure pump is formed by a pair of opposing pressure chambers formed by a part of the casing and a pair of diaphragms, a remaining portion of the casing, and the pair of diaphragms. A pair of pump chambers adjacent to the pair of pressure chambers, a pilot valve mechanism or an electromagnetic valve mechanism for alternately supplying and exhausting pressurized air supplied from an air supply source to the pair of pressure chambers, and the part of the casing. An air-driven double diaphragm pump comprising a rod that penetrates the pair of pressure chambers and connects the pair of diaphragms, and a suction valve and a discharge valve disposed in each pump chamber. The time required for one slurry driving is measured by detecting the dynamic pressure or the internal pressure fluctuation of the pressure chamber.
When the reciprocating constant discharge pressure pump is an air-driven double diaphragm pump, the time required for one slurry injection is measured by detecting the reciprocating movement of the rods that interconnect the pair of diaphragms or the internal pressure fluctuation of the pressure chamber. can do.

In the present invention, a reciprocating constant discharge pressure pump as a slurry driving pump and a control device for controlling the operation of the reciprocating constant discharge pressure pump are provided. The time required for one driving is measured and stored, and the ratio T1 / T2 between the driving time T1 immediately after the start of the high pressure driving in the current filtering operation and the driving time T2 immediately after the start of the high pressure driving in the previous filtering operation is less than 1. A filter press characterized by issuing a warning when it is determined that the slurry is leaking from the filter plate when the value is equal to or less than the predetermined value.
In the filter press according to the present invention, the leakage of slurry from the filter plate is quickly detected and an alarm is issued, so that the leakage prevention operation can be performed quickly and high processing efficiency can be realized.

According to the present invention, in a filter press equipped with a reciprocating constant discharge pressure pump as a slurry driving pump, a method of quickly detecting slurry leakage from a filter plate, which is an abnormality of the filter press, and a slurry leakage from a filter plate are quickly detected. A filter press is provided.

An abnormality detection method for a filter press according to an embodiment of the present invention will be described.
As shown in FIG. 1 (a), a fully automatic filter press 1 includes a pair of filter plates 2 that extend vertically and can move horizontally with the surface on which a recess 2a is formed facing each other, and the pair of filter plates 2 described above. A central plate 3 which is disposed between and extends vertically and has a slurry discharge port 3a formed therein, an air-driven double diaphragm pump 4 for driving slurry connected to the slurry discharge port 3a, and each filter plate 2 A filter cloth 5 disposed between the central plate 3 and extending vertically is provided. The fully automatic filter press 1 further includes a cake scraping member 6 having a pair of blades 6a that are in sliding contact with the central plate 3 and capable of moving up and down. The upper end of the filter cloth 5 is fixed to the cake scraping member 6, and a weight 7 fixed to the lower end of the filter cloth 5 applies a vertical tension to the filter cloth 5. The lower end corner portion 2b of the filter plate 2 and the piano wire 8 disposed immediately below the filter plate 2 are engaged with the filter cloth 5, and the filter cloth 5 is bent in a second shape.

The air-driven double diaphragm pump 4 includes a pair of opposing pressure chambers formed by a part of a casing and a pair of diaphragms as disclosed in, for example, Japanese Patent No. 3023872 and Japanese Patent Application Laid-Open No. 2007-120446. And a pair of pump chambers formed by the remaining portion of the casing and the pair of diaphragms and adjacent to the pair of pressure chambers, and pressurized air supplied from an air supply source are alternately supplied to the pair of pressure chambers. A pilot valve mechanism, a rod penetrating the part of the casing and entering the pair of pressure chambers to connect the pair of diaphragms, and a suction valve and a discharge valve disposed in each pump chamber. Yes. The pilot valve mechanism connects the one pressure chamber to the air supply path when the pair of diaphragms are displaced until the volume of one pressure chamber is minimized and the volume of the other pressure chamber is maximized. When the other pressure chamber is connected to the exhaust passage, the pair of diaphragms are displaced to a position where the volume of the one pressure chamber is maximized and the volume of the other pressure chamber is minimized, and as a result, the rod is displaced, The one pressure chamber is connected to an exhaust passage and the other pressure chamber is connected to an air supply passage. If the air-driven double diaphragm pump 4 is connected to an air supply source, the air-driven double diaphragm pump 4 alternately sucks fluid into the pair of pump chambers and alternately draws fluid from the pair of pump chambers by the operation of the pilot valve mechanism. The discharge operation is automatically repeated.

The fully automatic filter press 1 includes a control device 9. The control device 9 variably controls the pressure of the pressurized air supplied to the air-driven double diaphragm pump 4 and positions such as proximity sensors that detect the positions of the rods connecting the pair of diaphragms of the air-driven double diaphragm pump 4 Based on the detection signal of the sensor and a built-in timer, the number of times of slurry driving and the time required for one slurry driving are measured to control the operation of the pump 4.

The operation of the fully automatic filter press 1 will be described.
As shown in FIG. 1 (a), the cake scraping member 6 moves above the center plate 3, the center plate 3 and the filter plate 2 come into contact with the filter cloth 5 therebetween, and the recess 2a is sealed. In this state, the pump 4 is started, and the slurry is driven into the filter chamber formed by the sealed recess 2a through the slurry discharge port 3a of the center plate 3. The solid matter in the slurry is filtered by the filter cloth 5 and the water in the slurry that has passed through the filter cloth 5 is discharged out of the fully automatic filter press 1 through a discharge hole (not shown) formed in the filter plate 2.

In order to suppress clogging of the filter cloth 5, the control device 9 supplies constant pressure and low pressure air to the pump 4 for a predetermined time after the start of slurry driving, and the recess 2 a forms constant pressure and low pressure slurry. Drive into the filter chamber.
After continuing the low-pressure driving for a predetermined time, the control device 9 switches the pressurized air supplied to the pump 4 to a constant-high pressure pressurized air, and drives the constant-pressure slurry into the filter chamber formed by the recess 2a.

The control device 9 measures the time required for one slurry driving immediately after the start of the high-pressure driving for each filtering operation, and stores the time. The control device 9 determines that the ratio T1 / T2 between the driving time T1 immediately after the start of high pressure driving in the current filtering operation and the driving time T2 immediately after the start of high pressure driving in the previous filtering operation is less than 1, for example, 0.9 or less. In this case, the filter plate 2 and the center plate 3 are not sufficiently in close contact with each other, a gap is formed between them, and it is determined that the slurry is leaking from the gap, and an alarm is issued and the pump 4 is stopped. As a result, the leakage of the slurry from the filter plate 2 is discovered immediately after the start of the high-pressure driving of the slurry, and the position of the filter plate 2 and the central plate 3 can be quickly adjusted by maintenance personnel. Occurrence of loss of sex is prevented.
A change in the time of one-time driving due to the presence or absence of leakage from the filter plate 2 should be more noticeable at the time of high-pressure driving than at the time of low-pressure driving. Therefore, the time required for one injection immediately after the start of high pressure injection of slurry is measured and stored for each filtration operation, and the injection time T1 immediately after the start of high pressure injection in the current filtration operation and the high pressure injection in the previous filtration operation are stored. The slurry from the filter plate 2 is calculated by calculating the ratio T1 / T2 with the implantation time T2 immediately after the start and determining that the slurry is leaking from the filter plate 2 when the ratio is less than a predetermined value less than 1. It is possible to reliably and promptly detect an abnormality of the filter press such as leakage.

When the ratio T1 / T2 exceeds a predetermined value less than 1, the control device 9 determines that there is no slurry leakage from the filter plate 2 and continues the operation of the pump 4.
When the number of times of high-pressure driving of the slurry reaches a predetermined value, the control device 9 determines that the cake density in the filter chamber has increased to a predetermined value, and stops the operation of the pump 4.

As shown in FIG.1 (b), the filter plate 2 moves horizontally, leaves | separates from the center plate 3, and a cake falls out from the recessed part 2a. The cake scraping member 6 moves downward, and the blade 6 a moves downward while being in sliding contact with the central plate 3 to scrape the cake from the central plate 3. The filter cloth 5 to which the tension in the vertical direction is applied follows the cake scraping member 6 and moves downward. When the filter cloth 5 is engaged with the lower end corner 2b of the filter plate 2 and bent, the cake attached to the filter cloth 5 is peeled off from the filter cloth 5, and the filter cloth 5 is engaged with the piano wire 8. When bending, the cake remaining on the filter cloth 5 is scraped off from the filter cloth 5. When the cake is removed from the filter cloth 5, the cake scraping member 6 moves above the center plate 3, the filter plate 2 moves horizontally, contacts the center plate 3 with the filter cloth 5 interposed therebetween, and the recess 2a. And sealing of the slurry is resumed.
The slurry filtration and the cake removal after the filtration stop are automatically repeated, and the slurry filtration is performed fully automatically.

Instead of detecting the position of the rod connecting the pair of diaphragms, the variation in the internal pressure of the pressure chamber accompanying the supply / exhaust may be detected to measure the number of times of slurry driving or the time required for one slurry driving.
In the air-driven double diaphragm pump 4, the connection between the pressure chamber, the air supply path, and the exhaust path may be switched using an electromagnetic valve instead of the pilot valve. In this case, the position of the rod connecting the pair of diaphragms is detected based on a detection signal of a position sensor such as a proximity sensor, and when the rod is displaced to the maximum side, the pressure chamber on that side is connected to the exhaust path, The solenoid valve is connected so that the pressure chamber on the side is connected to the air supply passage, and when the rod is displaced to the other side to the maximum, the pressure chamber on that side is connected to the exhaust passage and the pressure chamber on the other side is connected to the air supply passage. Control the operation of the mechanism. If the air-driven double diaphragm pump 4 is connected to an air supply source, the air-driven double diaphragm pump 4 alternately sucks fluid into the pair of pump chambers and alternately draws fluid from the pair of pump chambers by the operation of the electromagnetic valve mechanism. Repeat the discharge operation.
Instead of the air-driven double diaphragm pump 4, a constant discharge pressure reciprocating pump having another structure in which the reciprocating pitch varies depending on the flow path resistance on the discharge side may be used.

The present invention is widely applicable to filter presses.

1 is a structural diagram of a fully automatic filter press in which an abnormality detection method according to an embodiment of the present invention is implemented.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fully automatic filter press 2 Filter plate 2a Recessed part 2b Lower end corner part 3 Center plate 3a Slurry discharge port 3b Recessed part 4 Air drive double diaphragm pump 5, 10 Filter cloth 6 Cake scraping member 6a Blade 7 Weight 8 Piano wire 9 Controller

Claims (4)

This is an abnormality detection method for a filter press equipped with a reciprocating constant discharge pressure pump as a slurry driving pump, and measures the time required for one driving immediately after the start of high pressure driving of slurry for each filtering operation. When the ratio T1 / T2 between the driving time T1 immediately after the start of driving and the driving time T2 immediately after the start of the high pressure driving in the previous filtering operation is equal to or less than a predetermined value less than 1, it is determined that the slurry is leaking from the filter plate. An abnormality detection method characterized by The reciprocating constant discharge pressure pump is formed of a pair of opposing pressure chambers formed by a part of a casing and a pair of diaphragms, a remaining portion of the casing and the pair of diaphragms, and is adjacent to the pair of pressure chambers. A pair of pump chambers, a pilot valve mechanism or electromagnetic valve mechanism for alternately supplying and exhausting pressurized air supplied from an air supply source to the pair of pressure chambers, and the pair of pressures penetrating the part of the casing An air-driven double diaphragm pump comprising a rod that enters the chamber and connects the pair of diaphragms, and a suction valve and a discharge valve disposed in each pump chamber, and the reciprocating motion of the rod or the internal pressure of the pressure chamber The abnormality detection method according to claim 1, wherein the time required for one slurry driving is measured by detecting the fluctuation. A reciprocating constant discharge pressure pump as a slurry driving pump and a control device for controlling the operation of the reciprocating constant discharge pressure pump are provided. The time required is measured and stored, and the ratio T1 / T2 between the driving time T1 immediately after the start of the high pressure driving in the current filtering operation and the driving time T2 immediately after the start of the high pressure driving in the previous filtering operation is less than 1. A filter press characterized by issuing an alarm when judging that slurry is leaking from the filter plate when the value is below the value. The reciprocating constant discharge pressure pump is formed of a pair of opposing pressure chambers formed by a part of a casing and a pair of diaphragms, a remaining portion of the casing and the pair of diaphragms, and is adjacent to the pair of pressure chambers. A pair of pump chambers, a pilot valve mechanism or electromagnetic valve mechanism for alternately supplying and exhausting pressurized air supplied from an air supply source to the pair of pressure chambers, and the pair of pressures penetrating the part of the casing An air-driven double diaphragm pump including a rod that enters the chamber and connects the pair of diaphragms, and a suction valve and a discharge valve disposed in each pump chamber, and the control device includes a reciprocating motion of the rod or a pressure chamber 4. The filter press according to claim 3, wherein the time required for one driving of the slurry is measured by detecting the internal pressure fluctuation.

Images