JPH0324247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a filtration device for filtering a suspension and discharging filter dregs discontinuously, and a method for operating the same.

Prior Art An intermediate partition plate is provided between the can body and the lid provided on the top of the can body, dividing the container into a stock solution chamber below and a filtrate chamber above. A filtration device in which one or more filter media are installed vertically and the inner space of the filter media is communicated with a filtrate chamber is known.

Such suspension devices are suitable for filtering large quantities of suspensions. Normally, the stock solution chamber is supplied with stock solution under pressure using a pump, etc., and the filtrate is collected from the filtrate chamber. When filter slag accumulates around the filter material and the filtration efficiency decreases, the supply of stock solution is stopped and the filter material is removed. The process is repeated by backwashing the suspension, discharging the liquid containing the filter dregs through a drain pipe installed at the bottom of the stock solution chamber, and then filtering the suspension again.

At this time, the waste liquid containing a high concentration of filter slag generated during the regeneration and cleaning of filter media is stored and accumulated to a certain extent and then sent to a waste liquid treatment facility, where useful components are recovered and then disposed of. . but,
Although it is a small amount of highly concentrated suspension, it is necessary to treat it periodically, and the waste liquid treatment equipment for this purpose is equipped with a complete set of equipment that has the same functions as large filtration equipment, even if it is small. I have no choice but to become

In addition, in the above-mentioned case, as a device that can efficiently filter a small amount of suspension and separate the filtrate and filtrate, we have developed a device that is mounted on a filter plate with a flat filter media support on the top surface. A filter cloth is placed on the filter cloth, and the upper lid and the periphery are brought into close contact with each other, and then the suspension is supplied and pressurized into the space formed by the lid and the filter cloth to perform filtration and remove the accumulation of filter slag. When the filtration efficiency decreases, the suspension supply is stopped and air is injected instead to reduce the mother liquor content in the filtrate, and then the lid and filter plate are opened to remove the filtration slag remaining on the filter cloth. A device for extracting the is known.

However, when the former and the latter are used together, it is difficult to balance the capabilities of the devices, which inevitably increases equipment costs and increases the amount of work required for operation.

Problems to be Solved The present invention efficiently processes a large amount of suspension,
In addition, we propose a new efficient and compact filtration device that can separate and discharge filter dregs with a low mother liquor content all at once without generating waste liquid from cleaning the filter media, and utilize this new filtration device. The present invention aims to provide a filtration and dehydration method.

Means for Solving Problems An object of the present invention as described above is to provide an intermediate partition plate with a filter medium hanging therebetween between the can body and the top cover, and to divide the internal space of the filter medium between the middle partition plate and the top cover. A main filter that communicates with a filtrate chamber formed by a filter body, and a filter plate that is configured to be able to move toward and away from a flange provided at a lower end opening of the main filter in the vertical direction, and whose upper surface A novel filtration and dewatering device is used, which includes a flat filter media support at a position, and a long sheet-like filter media that is provided between the flange portion and the filter plate and is movable in the length direction. Then, the stock solution is supplied to a stock solution chamber surrounded by the intermediate partition plate and the sheet-like filter medium, and the filtrate is collected from the filtrate chamber and, if necessary, the filtration plate. Then, the stock solution supply is stopped and pressurized air is introduced. After collecting as much filtrate as possible by supplying it to the filtrate chamber, the supply of pressurized air is stopped and the discharge of the filtrate is stopped, and then pressurized air is supplied to the filtrate chamber and the filtrate is recovered. The filter media of the main filter is backwashed by opening the chamber to allow air to escape, and then closing the concentrate chamber and backwashing the filter medium with pressurized air supplied to the filtrate chamber or the concentrate chamber. The turbid liquid is filtered through the sheet-like filter medium to collect the filtrate and the filter cake is dehydrated, and then the supply of pressurized air is stopped and the filter pan is moved downward, and the sheet-like filter medium is further moved. This can be achieved by repeatedly discharging the filter cake.

A novel filtration and dehydration apparatus for carrying out the method of the present invention is constructed as shown in FIG. That is, 1 is an upper lid body, which has a flange 1a at its lower end, and is further provided with a conduit 1b for discharging filtrate and introducing pressurized air. Reference numeral 2 denotes a can body, and the upper side wall is provided with a pipe line 2a for introducing pressurized air and discharging air, and the lower side wall is provided with a pipe line 2b for introducing the filtered stock solution. The lower ends have flanges 2c and 2d, respectively. 3 is an intermediate partition plate, and flange 1
a and the flange 2c. Reference numeral 4 denotes a filter medium vertically disposed on the intermediate partition plate 3, which is, for example, cylindrical in shape, and its internal space communicates with the space above the intermediate partition plate 3. Reference numeral 5 denotes a filter dish, which has a flange 5a at its peripheral edge and a conduit 5b for discharging the filtrate at its bottom. 6 is the filter plate 5
It is a flat filter media support provided on the top surface of the filter. Reference numeral 7 denotes a sheet-like filter medium, which is formed, for example, in the shape of an endless belt and is configured to go around a feed roller 7a and a take-up roller 7b.
7c is a scraper for peeling filter dregs from the filter medium 7. Further, 8 is a lifting means for moving the filtering plate 5 toward and away from the can body 2, and for example, a fluid pressure cylinder, a jack, or the like is used.

In the filtration and dehydration device having such a structure, the space inside the can body 2 surrounded by the intermediate partition plate 3 and the sheet-like filter medium 7 forms the stock solution chamber X, and the space between the upper lid body 1 and the intermediate partition plate 3 The space surrounded by forms the filtrate chamber Y. The lower part of the can body 2 is constricted, for example, into a conical shape, and the diameter of the filtration plate 5 is made smaller than the diameter of the can body 2. In this way, when the inside of the device is pressurized, the filtration plate 5 can be closed. The force required to maintain the closed state can be reduced, and the elevating means 8 can be made smaller or simpler.

When carrying out the method of the present invention using _the novel apparatus of _the present invention, as shown in FIG. Connect between the two using piping, valves, etc.

First, the elevating means 8 is operated to press the filter plate 5 together with the sheet-like filter medium 7 to the lower part of the can body 2, and then the filtration operation is started. Valves V ₁ , V ₂ , and V ₃ are opened, and the pump P supplies the stock solution from the stock solution tank T ₁ to the stock solution chamber X. The stock solution is filtered through the filter medium 4, enters the filtrate chamber Y, and flows out from the valve _V3 , and a portion is also filtered through the sheet-like filter medium 7 and flows out from the valve _V2 .
The filtrate is collected in tank _T2 . At this time, valve _V2 may be closed and the filtrate may be allowed to flow out only from valve _V3 .

Filter slag accumulates on the outer surface of the filter medium 4, but when the filtration resistance increases and the filtration efficiency decreases, the pump P
At the same time, the valve _V1 is closed, and the valve _V5 is opened to introduce pressurized air into the stock solution chamber X. In this way, the stock solution in the stock solution chamber X passes through the filtrate chamber Y and is recovered as a filtrate, and is also filtered and collected by the sheet-like filter medium 7, with only the filter dregs remaining on the outer surface of the filter medium 4 and the upper surface of the filter medium 7. During this time, the pressure of the air in the stock solution chamber X is maintained higher than the pressure in the filtrate chamber Y, so that the filter dregs remaining on the outer surface of the filter medium 4 do not peel off much.

Next, valve V ₃ and valve V ₅ are closed, valve V ₄ is opened to introduce pressurized air into filtrate chamber Y, and valve V ₆ is opened. At the same time, the air in concentrate chamber X escapes and the pressure decreases. The filtrate remaining in the filtrate chamber Y is pushed by the pressurized air, passes through the filter medium 4, and flows out all at once into the stock liquid chamber X, and the filter medium 4 is backwashed. As a result of this backwashing, a suspension containing a large amount of filter dregs accumulates on the filtration dregs remaining on the filter medium 7, but if valve V ₆ is closed, the added water introduced from valve V ₄ is removed. The pressurized air increases _the pressure in the raw liquid chamber
will be collected.

The filter dregs remaining on the filter medium 7 is dehydrated by pressurized air, but this will be more efficient if pressurized air is also introduced from valve _V5 . After the dehydration is completed, valves V ₄ and V ₅ are closed, and if necessary, valve V ₆ is opened, and after the air pressure inside and outside the device is balanced, the lifting means 8 is operated to move the filter pan 5 downward. Moving. Then, the rolls 7a and 7b are moved to pull out the sheet-like filter medium 7 and discharge the filter dregs, but the filter dregs are peeled off by the scraper 7c and the filter medium 7 is circulated and used again.

Effects of the Invention The dual filtration and dehydration apparatus of the present invention is constructed as described in detail above, and exhibits significantly improved filtration and dehydration efficiency by operating in accordance with the filtration and dehydration method of the present invention. In other words, it is possible to process a large amount of raw solution that does not have a high concentration of suspended matter and to discharge only the dehydrated filter slag without generating waste liquid from filter media cleaning, so the equipment is compact and requires only a small installation area. installation costs are also reduced,
In addition, the time required for driving operations was shortened, and the amount of driving work was also reduced.

As described above, the present invention is not only highly economical, but also has high filtrate recovery efficiency and low processing loss, and is therefore excellent in terms of effective use of resources and reduction of environmental pollution.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a dual filtration and dehydration device according to the present invention, and FIG. 2 is a flow sheet of a suspension filtration treatment facility including the dual filtration and dehydration device of the present invention. DESCRIPTION OF SYMBOLS 1... Upper lid body, 2... Can body, 3... Intermediate partition plate, 4... Filter medium, 5... Filter plate, 7... Sheet filter medium, 8... Lifting means, X... Stock solution chamber, Y ...filtrate chamber, T ₁ ... stock solution tank, P ... pump, T ₂ ... filtrate tank, V ₁ , V ₂ , ..., ... valve.

Claims (1)

[Scope of Claims] 1. An intermediate partition plate with a filter medium hanging therebetween is provided between the can body and the top cover body, and the internal space of the filter medium is communicated with a filtrate chamber formed by the middle partition plate and the top cover body. a main filter, a filter plate provided at the lower end opening of the main filter and configured to be able to move toward and away from the flange in the vertical direction, and having a flat filter medium support at the upper surface position; A dual filtration and dehydration device comprising a long sheet-like filter medium provided between the flange portion and the filter plate and movable in the longitudinal direction. 2. The upper lid body is equipped with a conduit for discharging filtrate and injecting air, the can body is equipped with a conduit for supplying stock solution and conduit for injecting air and discharging air, and the filtration plate is equipped with a conduit for discharging filtrate. 2. The device of claim 1, comprising a conduit. 3. The device according to claim 1 or 2, wherein the sheet-like filter medium is in the form of an endless belt. 4. A main filter in which an intermediate partition plate with a filter medium hanging thereon is provided between the can body and the top cover body, and the internal space of the filter medium is communicated with a filtrate chamber formed by the middle partition plate and the top cover body; A filtration plate configured to be able to vertically approach and separate from a flange provided at the lower end opening of the main filter, and having a flat filter medium support at the upper surface position; A filtration/dehydration device equipped with a longitudinally movable long sheet-like filter medium provided between the filter plate and the can body, surrounded by the intermediate partition plate and the sheet-like filter medium. The filtrate is collected from the filtrate chamber and optionally the filtration pan by supplying the stock solution to the stock solution chamber, and then stopping the stock solution supply and supplying pressurized air to the stock solution chamber to collect as much as possible. After collecting the filtrate, the supply of pressurized air is stopped and the discharge of the filtrate is stopped, and then pressurized air is supplied to the filtrate chamber and the stock solution chamber is opened to allow air to escape, thereby performing main filtration. The filter medium of the vessel is backwashed, and then the stock solution chamber is closed and the backwash suspension is filtered through the sheet-like filter material using the pressurized air supplied to the filtrate chamber or the stock solution chamber to collect the filtrate. At the same time, the filter slag is dehydrated, and then the supply of pressurized air is stopped, the filter plate is moved downward, and the sheet-like filter medium is further moved to discharge the filter slag. .