JPH10235111A - Immersion-type gravitational filtration device and filtration method using this device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a filter medium area and increase a filtration rate so that maintenance services are rapidly extended when a clogging occurs by making a filtration device discrete from a filtration tank as an independent installation and immersing the filtration device into the filtration tank when the device is used and further, performing a filtration process with the help of a filter medium to be attached to the lateral face or the bottom face of the filtration device using a liquid differential pressure between the outside and the inside of the filtration device, and removing the filtration device after its use. SOLUTION: This immersion-type gravitational filtration device 1 has a filter medium 3 mounted on the lateral face and the bottom face of a porous support frame 2 and the upper face exposed to an atmosphere, and a weight 5 attached to the lower part of the device 1 for inhibiting a buoyancy, and stabilization. To enlarge a filtrating area and minimize the buoyance of the device 1, the filter medium 3 is of a laminated type. The filtering process is performed by using only the differential pressure between the internal liquid level 7 of the filtration device 1 and the liquid level 8 of the filtration tank 4, and a filtration pressure is applied by maintaining and adjusting the water levels of both device 1 and tank 4. The liquid of the filtration tank 4 is filtered using the filter medium 3 and the filtered liquid is transferred into the filtration device 1. The filtrate contained in the device 1 is drained to the outside of the device 1 and the filtrating process is continued on account of a drop in the liquid level 7 in the filtration device 1. Thus it is possible to enlarge the total filtrating area and increase the filtrating rate to enhance the filtrating efficiency and further, facilitate anticlogging measures and maintenance services.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating and separating various mixtures from a liquid mixture, which is frequently performed by industrial activities.

[0002]

2. Description of the Related Art A conventional gravity filtration apparatus is a simple apparatus that does not use electric power or the like in a filtration operation. However, since a filter medium and a filtration tank are integrated, the area of the filter medium is limited, and thus the filtration speed is reduced. It is difficult to increase. Further, there is a disadvantage that it is difficult to perform maintenance such as quick replacement of the filter medium and cleaning when trouble such as clogging occurs.

[0003]

In the case of filtering a fine colloidal suspension or the like, a pressure filtration method in which pressure is applied more than necessary tends to cause clogging of the filter medium. For this purpose, a gravity filtration method performed with a weak pressure that does not cause clogging is more appropriate. However, in the conventional gravity filtration method, since the filter medium is integrated with the filtration tank, the filtration area is limited, and it is difficult to increase the filtration speed. Therefore, a method that can increase the area of the filter medium is established. In addition, it facilitates quick processing when maintenance is required, for example, when a precipitate is deposited on the filter medium and causes clogging.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a filter medium is mounted, and a part of a filtration device for performing a filtration operation is separated from a filtration tank to form an independent and separate facility. At the time of use, the filter is immersed in a filtration tank or the like, and filtration is performed using a filter medium attached to the side surface or the bottom surface of the filtration device by utilizing a liquid pressure difference between inside and outside of the filtration device. After use, it can be quickly removed and removed.

[0005] By adjusting the liquid level in the filtration device,
The liquid pressure difference between the inside and outside of the filtration device is adjusted to an appropriate pressure according to the object to be filtered, and filtration is performed while maintaining the pressure, thereby preventing clogging of the filter medium.

[0006] In order to increase the filtration speed, the filtration medium is processed into various shapes to increase the filtration area. At the same time, the buoyancy of the device is minimized by reducing the volume in the filtration device.

[0007] The filtration device is mounted or movable, and when used, the filtration device is immersed in a filtration tank, and then filtered in a stationary state. Alternatively, by performing filtration while moving up and down, a mobile filtration operation can be performed depending on the purpose of filtration, such as enabling selective filtration of a supernatant liquid having a small amount of suspension.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An immersion type gravity filtration device (1) is shown in FIG.
The filter medium (3) is attached to the side and the bottom of the porous support frame (2), and the upper surface is open to the atmosphere.
In order to prevent and stabilize buoyancy, a heavy object (5) is attached to the lower part of the device. This device is a separate device independent of the filtration tank (4), and is installed in a filtration tank or the like by a fixture (6) directly connected to a support frame during use. In this case, the filtration device does not necessarily need to be directly attached to the filtration tank,
It is also conceivable to install it on other equipment around the filtration tank such as a crane, or to install it by hanging it with a rope. The position of the fixture does not necessarily have to be at the center of the filtration device as shown in FIG. 1 and is a convenient part for mounting.

As the filter medium to be used, various filter media, such as a filter cloth, a metal wire mesh, and a polymer membrane, which can be attached to the apparatus, can be considered. The support frame is provided with a filter medium, and various materials such as metal, plastic, and other inorganic materials that can withstand the working pressure can be used.

In order to increase the filtration area and minimize the buoyancy of the apparatus, the filter medium is of a laminated type as shown in FIG. In addition, it is conceivable to form the filter medium into various shapes such as a star or a thin tube. FIG. 2 shows an example of the shape of the filter medium, and illustrations of heavy objects, fixtures, discharge pipes, and the like are omitted.

A suspension in water or other various liquids is an object to be filtered.

The filtration is carried out using only the pressure difference between the liquid level (7) in the immersion type gravity filter and the liquid level (8) in the filtration tank. The filtration is performed by the liquid in the filtration tank being filtered by the filter medium by the liquid pressure difference and moving into the filtration device. The filtration pressure is adjusted by adjusting and maintaining the water level between the liquid level in the filtration device and the liquid level in the filtration tank. The filtrate in the filtration device is pumped out as needed using a container or the like. Alternatively, it is removed from the system from the discharge pipe (9) using a siphon, a pump, or the like. In this case, the set position of the tip (10) of the discharge pipe is determined according to the maintenance of the filtration pressure or the purpose of use of the apparatus.

[0013] When used in a stationary state, the filtration device is immersed in a filtration tank and attached to the filtration tank or other equipment around the filtration tank by a fixture. Alternatively, after being attached to the filtration tank or other equipment around the filtration tank in advance, it is mechanically moved and immersed in a fixed place in the filtration tank. When the filtration device is immersed, filtration into the device is started. Next,
When the filtrate that has been filtered into the device is discharged out of the device, the liquid level in the device drops, and thus the filtration is continued. At the end of the work or at the time of inspection or repair, the device can be removed from the filter tank to perform the work without removing the contents of the filter tank.

When the filtration device is used in a place where it is difficult to use the fixing device such as a river or a sea area, as shown in FIG. 3, a float (11) is connected, and the filter (11) is floated on the water surface. Fixed and moored with a loop (12) or the like, and filtered.

When used in places where there are waves or splashes, such as in the sea, a protective cover (13) is provided as necessary to prevent the splashes of waves. In this case, a ventilation pipe (14) for maintaining the inside of the filtration device at atmospheric pressure is provided.

In use by movement, as shown in FIG. 4A, the filtration device is mechanically moved from the upper part of the filtration tank using a fixing tool, immersed in the filtration tank at a certain depth, and then filtered. According to the water level of the filtration tank or the purpose of the filtration, the filtration is performed sequentially from the upper part of the liquid layer while moving the filtration device downward as shown in FIG. 4A to FIG. 4B or FIG. 4C. When it is necessary to perform filtration operations with different filter media in parallel according to the purpose of filtration, a plurality of immersion gravity filtration devices having different filter media are arranged, and the required devices are alternately immersed to perform a filtration treatment. Note that FIG. 4 does not show details of the filtering device.

When the filtration is continued to remove the precipitate (21), the filtration device is inserted into the bottom of the filtration tank as shown in FIG. The filtration is continued until the water level becomes zero, that is, only the precipitate is formed, and the remaining liquid in the exuded precipitate is removed.
After the operation is completed, if necessary, the filter is pulled up and removed.

FIG. 5 shows a method for removing the filtrate from the apparatus.
As shown in the figure, the discharge pipe penetrates the filter medium, and the hose (2)
By connecting to 2) or the like, a method of discharging to the outside of the system using the liquid differential pressure is also conceivable.

[0019]

According to the present invention, the advantages of the conventional gravity filtration method can be utilized, and the filtration area can be easily increased, so that the filtration speed can be greatly improved as compared with the conventional gravity filtration method.

Since the filtration process can be performed while moving, it is possible to selectively filter a portion which is easy to filter, such as an upper portion and a lower portion of the liquid layer, thereby improving the efficiency of the filtration.

The amount of deposits on the filter medium is small, and clogging due to the deposits on the filter medium can be prevented. Further, it is not necessary to separately provide a precipitation tank and a filtration tank as in the related art.

Since the filtration device can be removed without removing the contents of the filtration tank, maintenance such as washing of the filter medium is facilitated. In addition, a series of operations such as filtration, washing of the precipitate, filtration, addition of a reagent to the precipitate, and filtration can be performed in one filtration tank.

By adjusting the liquid level difference between the filtration tank and the inside of the filtration device, it is easy to suppress the filtration pressure to a very small level, and it is possible to perform ultra-slow filtration that does not easily cause clogging.

By installing a filtration device at the bottom of the filtration tank and performing filtration, not only filtration but also dewatering of the precipitate can be performed.

Since the filtration is performed only by the liquid differential pressure, it can be used without a device such as a pressurizing and suction pump. For this reason, application to water supply and sewage treatment devices in an emergency as a simple mobile filtration device when energy such as electric power cannot be used, and use of a water intake device in river waters can be considered.

[Brief description of the drawings]

FIG. 1 shows an outline of an immersion gravity filtration device.

FIG. 2 shows an example of forming a filter medium.

FIG. 3 is an example of a case where the apparatus is used stationary.

FIG. 4 is an example in the case of using by moving.

FIG. 5 shows an example of a method for discharging a filtrate.

Claims (2)

[Claims] A filter medium (3) is attached to the side or bottom of a porous support frame (2). When used, it is immersed in a filtration tank (4) or the like to filter the liquid surface (7) in the apparatus. An immersion-type gravity filtration device that performs filtration by a liquid pressure difference from the liquid level (8) of the tank. 2. A filtration method in which this apparatus is installed in a filtration tank or a filtration target area such as a river or a sea area, and is carried out in a stationary state, and a filtration method in which a filtration apparatus is moved up and down in accordance with a liquid level of a filtration tank or the like. .