JPH0638886B2 - Filtration device and operating method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for efficiently filtering a suspension and a method for operating the same.

[Conventional technology]

As a device for filtering a large amount of a suspension, a vertical tubular filter having a tubular filter medium vertically provided in a stock solution chamber at the bottom and a filtrate chamber communicating with the inside of the tubular filter medium at the top is provided. It is known.

Such a filter is usually assembled and used in a filter device having a device configuration as shown in FIG. In such a filtration device, the stock solution is supplied to the stock solution chamber 1 by a pump or the like.
The filtrate is collected from the filtrate chamber 2 by pressure feeding to the cylindrical filter medium 3
When the filter residue is accumulated around the filter and the filtration efficiency is reduced, the supply of the stock solution is stopped first, and then the pressurized air is supplied to the filtrate chamber 2 to backwash the cylindrical filter medium 3 with the filtrate in the filtrate chamber 2. At the same time, the liquid containing the filter residue is sent to the drain recovery tank 4 or the like provided for the purpose through the drainage pipe connected to the lower part of the stock solution chamber, and then the tubular filter medium 3 is pre-coated with a filter aid or the like again. It was usual to operate by the procedure of entering the filtration operation.

Further, the drainage sent to the drain recovery tank 4 is subjected to gravity filtration using a filter cloth or the like, or a small-sized pressure dehydrator provided separately is used to separate the filter residue, and the filtrate part is the stock solution. In many cases, it was treated with a method such as supplying it to the filter together with the above.

[Problems to be Solved by the Invention]

In such a conventional filtration device, when gravity filtration is performed in the drain recovery tank, the drain recovery tank itself needs to be a flat type and large capacity having a large cross-sectional area, and the installation area must be wide. However, if a pressure dehydrator and a pressure pump are added, the recovery tank can be a vertical type with a small installation area, but the equipment cost is further increased and the operation is complicated. There was a problem.

On the other hand, the liquid discharged from the stock solution chamber by backwashing is directly sent to the closed-type pressure dehydrator by using the pressure of the pressurized air applied to the filter, and at the same time, the sludge is separated by filtration. In that case, the installation area can be reduced by omitting the drain recovery tank and providing a small-sized filtrate tank, but the backwashing of the tubular filter medium becomes incomplete due to the restriction of the filtration speed of the pressure dehydrator, and rather As a result, the filtration operation cannot be performed for a long time.

Therefore, the present invention has no such drawbacks and is intended to provide a compact filtration device that can be operated at a high operating rate, and an object thereof is to provide a method for operating such a filtration device efficiently. It is a thing.

[Means for Solving the Problems]

The above-mentioned object of the present invention is to provide a main filtration machine in which a cylindrical filter medium is vertically provided in a lower stock solution chamber and a filtrate chamber which communicates with the inside of the cylindrical filter medium is provided in an upper part, a stock solution supply pump, and an adjusting tank. A pressure filtration dehydrator and a liquid receiving tank are provided, and a pipe (a) connecting to the filtrate receiving tank, a pipe (b) connecting to the adjusting tank and a pressurized air pipe (c) are selected in the filtrate chamber. A drain pipe connected so as to communicate with each other and connected to the inlet of the pressure filtration dehydrator at the lower part of the stock solution chamber.
(d) and a pipe (e) communicating with the discharge side of the stock solution supply pump are connected so that they can communicate with each other, and a pipe (f) reaching the adjustment tank is connected to the upper part of the stock solution chamber. A pipe (g) leading to the liquid receiving tank is connected to the outlet of the pressure filtration dehydrator, and a pipe (h) leading from the liquid receiving tank to the suction side of the stock liquid supply pump and the raw liquid supply from the adjusting tank. This is achieved by a filtration device characterized in that a pipe (i) communicating with the suction side of the pump is provided.

And in such a filtering device, a dispersion liquid of the filter aid for pre-coating the filter medium is prepared in the adjusting tank, and the dispersion liquid is mainly circulated through the pipe (i), the pipe (e) and the pipe (b). Pre-coat the filter material of the filter and then pipe the stock solution
At the same time as supplying to the main filter via (e), the filtrate is piped (a)
After being collected in the filtrate receiving tank, the filtration operation is stopped, and then pressurized air is supplied from the pipe (c) to connect the main filter contents to the pipe (d).
The filtrate obtained at the same time as being fed to the pressure filtration dehydrator is collected in the liquid receiving tank through the pipe (g), and 1/10 of the content of the main filter is discharged during that time. Plumbing
(f) is opened to lower the internal pressure of the stock solution chamber to the atmospheric pressure, so that the filter residue on the filter medium is peeled off together with the filter aid, and the pipe (f) is closed again to remove all the contents of the main filter. Can be achieved by adopting a method of operating a filtration device, which comprises subjecting the above to a filtration treatment with the pressure filtration dehydrator.

[Work]

In the filtration device of the present invention, a main filter of a specific type is used, in which a cylindrical filter medium is vertically provided in the lower stock solution chamber, and a filtrate chamber which communicates with the inside of the cylindrical filter material is provided in the upper part thereof. The pipe (f) reaching the adjusting tank is connected with an on-off valve at the top, and the above pipe is used when precoating the filter aid.
A uniform precoat layer can be easily obtained by using (f), and in the case of backwashing the filter medium, the above piping (f) while operating with the pressure filtration dehydrator connected to the main filtration machine (f) By using, it is possible to perform efficient backwashing.

〔Example〕

The filtering device of the present invention is configured as shown in FIG. That is, in the figure, A is a main filter in which a cylindrical filter medium A ₂ is vertically provided in a lower stock solution chamber A ₁ and a filtrate chamber A ₃ which communicates with the inside of the cylindrical filter medium A ₂ is provided in an upper part, It is called a candle filter. B is a stock solution supply pump, C is an adjustment layer, D is a pressure filtration dehydrator, E
Is a receiving tank. In the filtrate chamber A ₃ above the main filter, a pipe (a) connecting to a filtrate receiving tank (not shown), a pipe (b) reaching the adjusting tank C, and a pressurized air pipe (c) are respectively provided with open / close valves and connected. Whether or not any of them communicate with the filtrate chamber A ₃ can be arbitrarily selected. In addition, a drain pipe (d) that communicates with the inlet of the pressure filtration dehydrator D and a pipe (e) that communicates with the discharge side of the stock solution supply pump B have open / close valves at the bottom of the stock solution chamber A ₁ below the main filter. It is provided and connected, and it is possible to arbitrarily select whether or not each of them communicates with the stock solution chamber A ₁ . Further, a pipe (f) leading to the adjusting tank C is connected to the upper part of the stock solution chamber A ₁ with an opening / closing valve.

Note that a pipe (g) for the liquid receiving tank E is connected to the outlet of the pressure filtration dehydrator D, a pipe (h) leading from the liquid receiving tank E to the suction side of the stock solution supply pump B, and an adjusting tank C. From the above, a pipe (i) communicating with the suction side of the stock solution supply pump B is provided with an on-off valve. Further, a pressurized air pipe (j) leading to the inlet of the pressure filtration dehydrator D is also provided.

When the suspension is filtered using the filtration device of the present invention having the above-mentioned configuration, first, a filter aid for precoating a tubular filter medium, for example, a dispersion liquid of diatomaceous earth is used in the adjusting tank C. To prepare. Then, the filter aid dispersion liquid is supplied to the inlet of the stock solution supply pump B through the pipe (i),
The pipe (e) is passed through the stock solution chamber A ₁ , the tubular filter medium A ₂ , and the filtrate chamber A ₃ in this order, and is circulated so as to return to the adjusting tank C again via the pipe (b). As for such a precoating procedure, a conventionally known method may be applied as it is, but the pipe (f) connected to the upper part of the stock solution chamber A ₁ is opened and a part of the filter aid dispersion liquid is put in the adjusting tank C. If the amount of circulating liquid is increased while returning to the original state, the thickness of the precoat layer on the tubular filter medium A ₂ can be made more uniform.

If the pre-coating on the tubular filter medium A ₂ is completed in this way, piping
(i) is closed and the pipe (h) is opened, the supply of the undiluted solution to the undiluted solution chamber A ₁ is started, the filtration step is started, and the filtrate is recovered from the pipe (a).

In the filtration step, as time passes, the filter cake accumulates on the cylindrical filter medium A ₂ , and the filtration rate and the filtration pressure increase in sequence, but when the filtration efficiency falls to a predetermined limit in this way, Need to be regenerated by backwashing. In the filtering device of the present invention, the backwashing operation of the filter medium is carried out as follows.

First, the pipe (e) is closed to stop the undiluted solution supply to the undiluted solution chamber A ₁ , and then the pipe (a) is closed and the pressure of the pressurized air from the pipe (c) to the filtrate chamber A ₃ is applied. When d) is opened and the stock solution chamber A ₁ is communicated with the pressure filter dehydrator D, the filtrate from the pressure filter dehydrator D can freely flow into the liquid receiving tank E through the pipe (g). The clean filtrate in A ₃ passes through the cylindrical filter medium A ₂ and flows back to the stock solution chamber A ₁ , and the filter residue is filtered through the cylindrical filter medium A 2.
While peeling from ₂ , it flows into the pressure filtration dehydrator D, is filtered, and enters the liquid receiving tank E. At this time, since the pressure filtration dehydrator D has a relatively high filtration resistance, the washing speed cannot be increased. However, even if more than 1/10 of the content of the main filter A has moved to the pressure filtration dehydrator D (for example, after 10 seconds have elapsed), when the pipe (f) is opened, the internal pressure of the stock solution chamber A ₁ is released. As a result, the pressurized air in the filtrate chamber A ₃ rapidly passes through the cylindrical filter medium A ₂ together with the remaining clean filtrate to separate the filter residue. At that time, a part of the liquid is ejected from the pipe (f), which is received by the adjusting tank C. In this way, after the filter residue is completely separated and dropped (for example, after 30 seconds), the pipe (f) is closed, the internal pressure of the stock solution chamber A ₁ is increased, and all the discharged liquid containing the filter residue is transferred to the pressure filtration dehydrator D. Send in,
The filtrate is collected in the liquid receiving tank E.

When the backwashing of the filter medium is completed by the above operation, the filtering device returns to the initial state, and the next filtering cycle can be started again.

〔The invention's effect〕

The filtration device of the present invention can be opened above the stock solution chamber in a main filter of a specific type in which a cylindrical filter medium is vertically provided in the lower stock solution chamber and a filtrate chamber communicating with the inside of the tubular filter material is provided in the upper part. Not only can the installation area be small and the backwashing of the filter medium can be performed very efficiently with a simple operation, since it is constructed by combining pipes and using a specific device. In the case of precoating the filter aid, there is a feature that a uniformized precoat layer can be easily obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a filtration device of the present invention, and FIG. 2 is a circuit diagram showing a configuration of a conventional filtration device. A ...... main filter machine, _{A 1} ...... stock chamber, _{A 2} ...... cylindrical filter medium,
A ₃ ... filtrate chamber, B ... stock solution supply pump, C ... adjusting tank, D ... pressure filtration dehydrator, E ... receiving layer, (a), (b),
(c), (d), (e), (f), (g), (h), (i), (j) ... Piping, 1
... stock solution chamber, 2 ... filtrate chamber, 3 ... tubular filter material, 4 ... drain collection tank.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takemi Yanashita 19-1 Narumigo, Haguro, Inuyama, Aichi Prefecture Sanshin Manufacturing Training Center

Claims (4)

[Claims] 1. A main filtration machine having a cylindrical filter medium vertically provided in a lower stock solution chamber and a filtrate chamber communicating with the inside of the cylindrical filter medium in the upper part, a stock solution supply pump, an adjusting tank, and a pressure filter. Dehydrator,
A liquid receiving tank, and piping for connecting to the filtrate receiving tank in the filtrate chamber
(a) and the pipe (b) communicating with the adjusting tank and the pressurized air pipe (c) are connected so that they can selectively communicate with each other, and the lower part of the stock solution chamber is communicated with the inlet of the pressure filtration dehydrator. The drain pipe (d) and the pipe (e) communicating with the discharge side of the stock solution supply pump are connected so that they can communicate with each other, and the pipe (f) reaching the adjusting tank is connected to the upper part of the stock solution chamber. A pipe (g) leading to the liquid receiving tank is connected to the outlet of the pressure filtration dehydrator, and a pipe leading from the liquid receiving tank to the suction side of the stock solution supply pump.
(h) and a pipe (i) communicating from the adjusting tank to the suction side of the stock solution supply pump, wherein the filtering device is provided. 2. A pressurized air pipe (j) at the inlet of the pressure filtration dehydrator.
The filtration device according to claim 1, further comprising: 3. The filter device according to claim 1, wherein a dispersion of a filter aid for pre-coating a filter medium is prepared in an adjusting tank, and the pipe (i) and the pipe (e) are prepared. ) And pipe (b) to precoat the filter material of the main filter by circulating the dispersion liquid, and then feed the undiluted solution to the main filter via pipe (e) and the filtrate through pipe (a) at the same time. After collecting in the receiving tank and stopping the filtration operation, the pressurized air is piped (c)
At the same time as feeding the main filter contents into the pressure filtration dehydrator through the pipe (d), the filtrate obtained is pipe (g)
The liquid is collected in the liquid receiving tank via the pipe, and at least 1/10 of the content of the main filter is discharged during that time, and then the pipe (f) is temporarily
Is opened to reduce the internal pressure of the stock solution chamber to the atmospheric pressure, whereby the filter residue on the filter medium is peeled off together with the filter aid,
A method for operating a filtration device, characterized in that the pipe (f) is closed again and the content of the main filter is filtered by the pressure filtration dehydrator. 4. The pipe (f) is closed and the contents of the main filter are fed into the pressure filtration dehydrator, and then pressurized air is supplied to the pressure filtration dehydrator using the pipe (j). Operation method described in item (3).