JPH06309A - Method and device for dehydrating filter - Google Patents

Abstract

PURPOSE:To provide an effective method and device for dehydrating a filter where the dehydration of the spent diatomaceous earth removed from a filter medium is finished in a shorter time than the one required for the precoating of diatomaceous earth to the filter medium and the filtering time. CONSTITUTION:When discharging liquid contg. spent diatomaceous earth from a filter cylinder 4 to be dehydrated, after pressurized air is blown into the filter cylinder 4 from an air supply part 10 to remove the diatomaceous earth precoated on the surface of the filter medium, a process 19 where the removed diatomaceous earth is agitated is provided before dehydrating it with dehydrating filter paper 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing pre-coated diatomaceous earth whose performance has been lowered by using it from a filter surface and dehydrating it.

[0002]

2. Description of the Related Art A filter is known in which diatomaceous earth is pre-coated on the surface of a filter and is filtered as a diatomaceous earth filter. In such a diatomaceous earth filter,
When the filtration efficiency decreases, the diatomaceous earth adhering to the surface of the filter is backwashed, peeled from the filter core material and sent to the precoat tank.Add diatomaceous earth to this and precoat the filter core material again for use. However, when the filter efficiency does not improve even if the diatomaceous earth is backwashed due to an increase in the filter residue (objects to be filtered such as processing waste), the diatomaceous earth is peeled off from the filter by the backwashing process. These are transferred to a dehydration cylinder, and pressure dehydration is performed in the dehydration cylinder using a filter cloth or the like.

That is, for example, as shown in FIG. 8, a filter material 3 in which a coil-like core material 1 is covered with a net-like outer skin 2 whose lower part is closed is placed inside a filter cylinder 4 as shown in FIG. A large number of bearings are supported, a filtrate containing diatomaceous earth 5 is supplied from the outside of the filter material 3, and the outer skin 2 of the core material 1 is precoated with diatomaceous earth 5 as shown in FIG. .

Since the filter core material 6 is constructed in this way, the filtrate is usually supplied from the lower inlet 4a of the filter cylinder 4, and passes through the filter core material 6 and is discharged outside as an filtered liquid from the upper outlet 4b. However, when the filtration performance is deteriorated, air is blown from the upper outlet 4b to inflate the filter material 3 to cause cracks in the precoated diatomaceous earth 5 and the diatomaceous earth 5 to be filtered. ) Together with the filter material 3 by air pressure.

When the exfoliated diatomaceous earth 5 is reused,
While supplying the filtrate from the lower inlet 4a of the filter cylinder 4, the diatomaceous earth that was peeled off was discharged from the intermediate outlet 4c in a state of being mixed with the filtrate without passing through the filter material 3 and transferred to the precoat tank 9, to which new diatomaceous earth was added. With or without addition,
The core material 2 is precoated with the diatomaceous earth by allowing the filtrate to flow from the lower inlet 4a into the filter cylinder 4 and discharging the filtrate from the upper outlet 4b.

When the separated diatomaceous earth is discarded,
The filtrate is dropped together with the filtrate into a dehydrating cylinder 7 connected to a discharge port 4d provided at the bottom of the filtering cylinder 4, and the filtrate is separated using a dehydrating pressurized air through a dehydrating filter cloth 8 provided at the lower part of the dehydrating cylinder 7. After that, the diatomaceous earth is discarded together with the object to be filtered (filter residue).

FIG. 4 shows an embodiment in which a working fluid of an electric discharge machine is filtered as such a filtering device. Further, FIG. 5 shows the opened / closed state of the valve during the operation.

To further explain such a conventional device, as shown in FIG. 4, the filter device comprises a filter cylinder 4, a precoat tank 9 for supplying diatomaceous earth 5 for precoating the filter surface of the filter cylinder, and a filter. A backwash air supply unit 10 for peeling the filter residue attached to the surface together with the diatomaceous earth from the filter surface, and connecting to a filter cylinder to separate and dehydrate the diatomaceous earth and the filter cake and the processing liquid peeled from the filter surface. It is composed of a dehydrating cylinder 7 provided with the provided dehydrating filter cloth 8 and piping provided with a valve connecting these. In the figure, reference numeral 11 is a diatomaceous earth feeding machine, and 12 is a diatomaceous earth feeding apparatus to the precoat tank 9.

In order to operate such a filtering device,
First, it is necessary to attach diatomaceous earth to the filter core material of the filter. Therefore, the stock solution inlet valve V from the working solution supply device
₁ is closed, and diatomaceous earth is introduced into the precoat tank 9 containing the working fluid from the diatomaceous earth feeder 11 through the feeder 12 and is fed to the filter cylinder 4 by the pump P from the precoat inlet valve V ₃ to filter the filter. After passing the core material and adhering the diatomaceous earth on the surface, the processing liquid is discharged from the upper outlet 4b of the filtration cylinder, the precoat outlet valve V ₄ is opened and returned to the precoat tank, and the diatomaceous earth is charged again here. Diatomaceous earth is attached to the filter core material to a required thickness. During this work, the filtrate outlet valve V ₂ to the filtrate supply tank is closed.

Further, a backwash valve V is provided on the upper part of the filter cylinder 4 in order to separate the diatomaceous earth 5 adhering to the filter material 3 together with the filter cake.
Pressurized air is supplied via ₅ and a dehydration cylinder 7 is provided below the filtration cylinder 4 via a drain valve V _6.
Is connected and installed, and similarly pressurized air is supplied to the air supply valve V.
It is configured to be supplied to the upper part of the dehydration cylinder via ₈ . In the figure, reference numerals PG ₁ and PG ₂ are pressure gauges,
V ₇ is a backwashing diatomaceous earth mixed solution and an air bleeding valve for backwashing the filter cylinder 4.

FIG. 5 shows the open / closed state of each valve in the precoating step, the filtering step, the backwashing step, the dehydration preparing step, and the dehydrating step.
FIG. 6 shows a flow chart of the operation of the filtration device.

Next, FIG. 6 will be described. After the diatomaceous earth addition, the pre-coating step and the filtration step, it is judged whether the pressure of the filtration set value PG ₁ is over. If it is over, the intermediate backwashing step and the re-precoating step are repeated for the intermediate backwashing counter, and when the counter is incremented, the filtration step is transferred to the backwashing step. When all the liquid in the filtration cylinder has flowed into the dehydration cylinder, the dehydration process is started and the discharge process is started.

A filter cloth 8 wound in a roll shape is movably provided on the lower part of the dehydrating cylinder 7 by a winding device 13. Through the filter cloth 8, the filtrate is guided to a dehydration receiving stand 14. He will be returned to the tank. This dehydration cradle
14 is pressed against the lower part of the dehydrating cylinder by a hydraulic cylinder 16 driven by a hydraulic device 15 with a filter cloth 8 interposed therebetween. The upper part of the dehydrating cylinder 7 which has received the filtrate and the diatomaceous earth / slag from the filtering cylinder 4 is pressed with pressurized air, The diatomaceous earth and the filter cake are left on the filter cloth 8 for dehydration. After the dehydration is completed, the pedestal 14 and the filter cloth 8 are lowered, and the filter cloth 8 is moved to plate the diatomaceous earth and the filter residue left on the surface thereof.
It is scraped off into a tip bucket 18 at 17.

[0014]

By the way, in the conventional apparatus, in order to dehydrate the used diatomaceous earth peeled from the filter material, a time longer than the time required for precoating the diatomaceous earth on the filter material and the filtration time is required. In some cases, the operation of the filtration device had to be stopped until the used diatomaceous earth was dehydrated, which was inefficient.

The present invention is intended to ameliorate the drawbacks of the conventional apparatus by making it possible to shorten the dehydration time of the used diatomaceous earth and the filter cake.

[0016]

The present invention is intended to solve the above-mentioned problems by adopting the following constitution. That is, (1) In a filter in which diatomaceous earth is pre-coated on the surface of a filter provided in the filter cylinder to perform filtration, when the used diatomaceous earth is discharged and dehydrated from the filter cylinder, After the backwashing air is blown, the diatomaceous earth and filter residue pre-coated on the surface of the filter are peeled off, and a step of stirring the separated diatomaceous earth and filter residue together with the filtrate is provided before dehydrating this with a filter cloth for dehydration. Filter dehydration method. (2) Filter cylinder, precoat tank for supplying diatomaceous earth for precoating the filter surface of the filter cylinder, backwashing air supply unit for peeling filter residue adhering to the filter surface together with diatomaceous earth from the filter surface, filter surface Dewatering cylinder provided with a filter cloth for dehydration provided to be connected to the filter cylinder for separating and dehydrating the separated diatomaceous earth and filter cake and the filtrate, and with a pipe connecting these,
A dehydrator for a filter, wherein a stirring device for stirring a mixed liquid of the filtrate, diatomaceous earth separated from the surface of the filter, and filter cake is connected between the filter cylinder and the dehydration cylinder.

[0017]

[Function] After a mixture of diatomaceous earth and processing waste (filter residue) and processing liquid separated from the filter material in the filter cylinder is stirred and mixed by a stirrer, it is led to a dehydration cylinder equipped with a filter cloth at the bottom, and this is introduced. Since the working fluid is passed through and dehydrated by pressurizing with pressurized air, the diatomaceous earth does not become solid,
In addition, the state in which the processing waste adhered to the surface of diatomaceous earth was eliminated,
Since the passage resistance of the working fluid is reduced, the dehydration time can be shortened.

[0018]

EXAMPLE A filter device for filtering and reusing a machining fluid containing machining chips of an electric discharge machine will be described as an example.
FIG. 1 is an explanatory view showing the configuration of a filtration device according to the present invention, which is different from the conventional device in that a mixture of diatomaceous earth and processing waste and processing fluid separated from a filter material is provided between a filtration tube and a dehydration tube. It is characterized in that a stirrer is provided.
FIG. 3 is an explanatory view showing each valve switching operation state in the device shown in FIG. 1.

As shown in FIG. 1, the filtration apparatus according to the present invention has a filter cylinder 4, a precoat tank 9 for supplying diatomaceous earth 5 for precoating the filter material surface of the filter cylinder, and a diatomaceous earth adhered to the filter material surface. Backwashing air supply part 1 for peeling processing waste from the surface of the filter material 1
0, a dehydration cylinder 7 provided with a dehydration filter cloth 8 provided in connection with the filtration cylinder 4 for separating and dehydrating the diatomaceous earth and the processing waste separated from the surface of the filter material and the processing liquid, and a pipe connecting these And the diatomaceous earth separated from the surface of the filter material with the processing liquid between the filtration cylinder 4 and the dehydration cylinder 7,
It is composed of a stirring device 19 for stirring the mixed liquid with the processing waste.

In order to operate the filtering device, it is necessary to first attach diatomaceous earth to the filter material of the filter cylinder 4,
Since these operation processes are the same as those described for the conventional device, the description thereof will be omitted.

FIG. 2 shows the opening / closing state of each valve in the precoating step, filtering step, intermediate backwashing step, intermediate precoating step, backwashing step (stirring step), dehydration preparation step, and dehydration step.
A flow chart of the operation of the filtration device is shown in FIG.

Next, FIG. 3 will be described. The difference from FIG. 6 is that when the intermediate backwash counter is up, the intermediate backwash step is performed once and then the backwash step is performed. That is, in the intermediate backwashing process, in FIG. 1, the valve 5 and the valve 7 are opened, the diatomaceous earth and the filter cake adhering to the surface of the filter are separated by the pressurized air, and the pressurized air is continuously fed to the inside of the filter cylinder. It is essential to generate a large number of bubbles in the working fluid and to stir them. However, since the stirring device 19 is provided in FIG. 1, the stirring step may be performed between the backwashing step and the dehydration step without interposing the stirring step immediately before the backwashing step as in this flowchart. . That is, the stirring step may be performed before proceeding to the dehydration step.

By the way, in the filtration device according to the present invention, the stirring device 19 is provided between the filtration cylinder 4 and the dehydration cylinder 7 connected to the lower part thereof through the valves V ₉ and V ₁₀ , respectively. Here, the mixture of diatomaceous earth, filter cake, and filtrate separated from the surface of the filter that is dehydrated and removed is once subjected to a stirring and mixing action, and is supplied to the dehydrating cylinder 7 in a uniformly mixed state. Therefore, the dehydration work from the mixture of diatomaceous earth, filter cake and filtrate is close to the state where the intermediate backwashing step in the filtration step has been completed, and the passage resistance of the filtrate is reduced, so it can be completed in a short time. become.

In FIG. 1, the stirring device 19 is provided between the filtration cylinder 4 and the dehydration cylinder 7, but this stirring device 19 may not be provided and the stirring action can be performed by other means. That is, using the conventional hardware configuration (FIG. 4) in which the filtration cylinder 4 and the dehydration cylinder 7 are connected via the valve V ₆ , the valves V ₅ and V ₇ are opened immediately before the backwashing step and the intermediate reverse process is performed. Perform the same operation as the washing step. This means that the diatomaceous earth and the filter cake adhering to the filter surface are peeled off by the pressurized air, and by continuing to feed the pressurized air, a large number of bubbles are generated in the working fluid in the filter cylinder and the mixture is agitated. After that, it is sufficient to proceed to the backwash process. Therefore, by controlling the opening / closing of the valve, it is also possible to intervene immediately before the intermediate backwashing step and the backwashing step and use this as a stirring means.

[0025]

According to the present invention, as the method and apparatus for interposing the stirring step before the dehydration step, a stirring device 19 is provided between the filtration cylinder 4 and the dehydration cylinder 7 connected to the lower portion thereof. By interposing, the mixture of diatomaceous earth, filter cake, and filtrate exfoliated from the surface of the filter to be dehydrated and removed is subjected to a stirring and mixing action, and then these are dehydrated in a uniformly mixed state. Work can be efficiently completed in a short time.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a filtration device according to the present invention.

FIG. 2 is an explanatory diagram showing an open / closed state of a valve at the time of switching the operation in FIG.

FIG. 3 is a flowchart showing an example of a filtration method according to the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a filtration device according to a conventional example.

5 is an explanatory diagram showing an open / closed state of a valve at the time of switching the operation in FIG. 4. FIG.

FIG. 6 is a flowchart of a filtration method according to a conventional example.

FIG. 7 is an explanatory diagram showing the internal structure of a filter cylinder.

FIG. 8 is an explanatory diagram showing a configuration of a filter.

[Explanation of symbols]

 1 Coil Spring Core Material 2 Core Material 3 Filter Material 4 Filter Tube 5 Diatomaceous Earth 6 Filter Core Material 7 Dehydration Tube 8 Filter Cloth 9 Precoat Tank 10 Air Supply Section 11 Diatomaceous Earth Feeder 12 Sending Device 13 Filter Cloth Winding Device 14 Receiving Table 15 Hydraulic system 16 Hydraulic cylinder 17 Blade 18 Tip bucket 19 Stirrer

Claims (2)

[Claims] 1. A filter in which diatomaceous earth is pre-coated on the surface of a filter provided in the filter cylinder to perform filtration, and when the used diatomaceous earth is discharged and dehydrated from the filter cylinder, the filter is placed in the filter cylinder. After the backwashing air is blown, the diatomaceous earth and filter residue pre-coated on the surface of the filter are peeled off, and a step of stirring the separated diatomaceous earth and filter residue together with the filtrate is provided before dehydrating this with a filter cloth for dehydration. Filter dehydration method. 2. A filter cylinder, a precoat tank for supplying diatomaceous earth for precoating the filter surface of the filter cylinder, a backwashing air supply unit for peeling the filter residue adhering to the filter surface together with the diatomaceous earth from the filter surface, A diatomaceous earth and a filter cake separated from the filter surface, and a dehydration cylinder provided with a dehydrating filter cloth connected to the filtration cylinder in order to separate and dehydrate the filtrate, a pipe for connecting them, and a filtration cylinder. A dehydrator for a filter, wherein a dehydrator and a stirrer for stirring a mixed liquid of the diatomaceous earth and the filter cake separated from the surface of the filter are connected between the dehydrator and the dehydrator.