JP6019722B2 - Liquid filtration device and ballast water treatment device - Google Patents

Description

  The present invention relates to a liquid filtration device that continuously filters liquid, and particularly to a liquid filtration device that can be used as a ballast water treatment device stored in a ship.

  A wide variety of filters are used for the purpose of separating and removing solids as contaminants from gases and liquids. Patent Document 1 discloses that a filter device for removing sludge from cutting fluid of a machine tool is formed in a cylindrical shape. An example using a modified pleated filter is shown. In this device, it is said that a filter device having a high filter cleaning effect can be provided by ejecting liquid toward the outer surface of the filter while rotating the cylindrical filter.

  On the other hand, in recent years, the treatment of ballast water loaded on ships has become a problem. Ballast water is seawater that is loaded on a ship for safe navigation even in an empty state, and various methods for purifying ballast water to remove or kill or inactivate microorganisms have been studied. For example, Patent Document 1 discloses a filtration / separation device for removing particles and microorganisms from a liquid, a conical inflow chamber, a filtration / separation chamber, a discharge chamber having a sludge discharge port, and an upper discharge. A filtration / separation device having a configuration including a pipe, a screen filter, and a lower discharge pipe is described. Patent Document 2 discloses a ballast having a configuration in which filtration is performed while washing the outer surface of a filter by a treated water nozzle that uses a filter arranged in a freely rotatable cylinder and flows out the treated water toward the outer peripheral surface of the filter. A water production device is described.

Japanese Patent No. 4817601 JP 2011-251284 A

  When using brackish water and seawater such as seawater desalination and ballast water, or water treatment such as sewage, domestic wastewater, and industrial wastewater, pre-filtration treatment is required to remove foreign substances, dust, and microorganisms in the water. In such a filtering device, it is necessary to filter a large amount of processing liquid in as short a time as possible, but large-scale, high-flow operation generally tends to cause a reduction in processing volume and filtering function due to early clogging. Problem. In patent document 1, it is set as the structure which isolate | separates particle | grains heavier than a liquid with a centrifugal motion by the circular flow which forms a vortex | eddy, and filters the liquid which does not contain a particle. However, since the filtration surface is not cleaned, clogging is unavoidable, and treatment such as chemical cleaning is required after a certain amount of operation.

  The invention described in Patent Document 2 is configured to perform filtration while washing the filtration surface of the filter by rotating a cylindrical filter and ejecting water to be treated from the nozzle to the outer surface thereof. With this configuration, the filtration surface of the filter can be filtered while being repeatedly washed, so that clogging hardly occurs and a large amount of filtration can be continuously performed for a long time. In order to perform a large amount of filtration such as ballast water treatment with such an apparatus, it is necessary to increase the filtration area, and the cylindrical filter itself is naturally large and heavy. In order to rotate such a filter, a large motor is required, and there is a problem that the amount of electric power for operation increases. In addition, by spraying the water to be treated on the outer peripheral surface of the pleated filter, a force is applied to spread the pleat of the filter, and the stress applied to the upper and lower lake bottoms and the bent part of the filter may cause damage was there.

  Therefore, an object of the present invention is to provide a liquid filtration device capable of filtering a large amount of liquid to be treated with a simpler structure and capable of a long-time filtration operation, and a ballast water treatment device using the same.

  The present invention includes a filter having a filtration membrane arranged in a cylindrical shape, a case provided so as to accommodate the filter, a treatment liquid flow path for supplying a treatment liquid into the cylinder of the filter, Liquid filtration comprising: a filtrate flow path for taking out the filtrate filtered by the filter to the outside of the case; and a drain flow path for taking out the liquid to be treated that has not been filtered by the filter from the inside of the cylinder of the filter to the outside. An apparatus to be processed, the liquid to be processed being jetted from the liquid flow path to be processed toward the inner surface of the filter membrane of the filter, wherein the liquid nozzle to be processed is the filter It is comprised so that it may rotate centering on the cylindrical axis | shaft of this, The liquid filtration apparatus characterized by the above-mentioned.

  As described above, the apparatus conventionally considered has a configuration in which a cylindrical filter is rotated, and a cleaning liquid is ejected from a nozzle fixed to the outside to the outer peripheral surface of the filter, which is a filtration surface. The apparatus of the present invention is configured to perform filtration from the inner surface of the filter toward the outside, and supplies the liquid to be treated to the inside of the cylindrical filter. For this reason, it is sufficient to rotate the liquid nozzle to be processed without rotating the filter. Since the nozzle is lighter than the filter and is small because it is housed inside the cylinder, the rotational torque can be small, the motor can be miniaturized, and the operating power can be kept low. Furthermore, in order to prevent liquid leakage from the sliding part between the rotating shaft and the case, a normal movable seal is required, but the rotating mechanism of the nozzle rotating shaft is lighter than the rotating shaft of a large filter. Thus, reliable sealing can be performed with a simpler structure.

  The filtration membrane may be a vertical pleat filter having a pleated shape in which a plurality of crests and troughs are continuous so as to make a fold in the cylindrical axis direction. This is because a large filtration area can be secured and a large amount of liquid can be filtered with a compact device. In addition, the present invention provides a further effect when it is such a pleated filter. That is, compared with the case where the liquid to be treated that is the cleaning liquid is ejected from the outer surface of the pleat, the repetitive stress applied to the pleat is smaller in the case of ejection to the inner surface, and the filter is less likely to be damaged.

  The filtration membrane may be a horizontal pleated filter having a pleated shape in which a plurality of ridges and valleys are continuous so as to form a fold in a direction perpendicular to the cylindrical axis. This is because a large filtration area can be secured and a large amount of liquid can be filtered with a compact device. In the horizontal pleated filter of the present invention, even if the upper and lower cylinders are sealed and fixed by the upper lid and the bottom lid, the pleats other than the upper and lower ends are not fixed and are brought into a free state. In other words, when a force in the direction of expanding the pleats is applied due to the ejection of the cleaning liquid, the vertical pleat filter is fixed because the upper and lower ends are fixed, and stress is applied, causing a possibility of breakage. In horizontal pleats, since there is no fixed end, such stress is unlikely to occur and breakage is unlikely to occur. Furthermore, the horizontal pleat filter can be folded and stored like a lantern, so that the portability and storage are significantly improved and the cost merit is great.

  When such a horizontal pleat filter is used, since the pleats of the filter to be cleaned are arranged in the direction of the rotation axis of the nozzle, the cleaning nozzle can be arranged in accordance with the pleat interval of the filter. That is, a plurality of liquid nozzles to be processed may be provided, and the plurality of liquid nozzles to be processed may be provided so as to be separated from each other in the direction of the cylindrical axis and in the circumferential direction around the cylindrical axis. It is preferable to dispose the nozzles in a spiral manner, and the nozzle corresponding to each pleat can obtain a sufficiently widened cleaning effect. A high cleaning effect means that filtration with a smaller amount of liquid to be treated is possible, leading to reductions in pump equipment costs and power costs by improving filtration efficiency.

  Moreover, this invention provides the ballast water treatment apparatus which uses the above liquid filtration apparatuses as a seawater filtration apparatus. The liquid filtration device of the present invention capable of increasing the capacity and capable of continuously filtering a large amount of liquid for a long time has a merit of reducing the operating power cost with a relatively compact configuration, and is used as a processing device for marine ballast water. Suitable for that.

  According to the above invention, it is possible to provide a liquid filtration apparatus capable of filtering a large amount of liquid to be treated with a simpler configuration and capable of a long-time filtration operation, and a ballast water treatment apparatus using the liquid filtration apparatus.

It is a cross-sectional schematic diagram which shows the structural example of the liquid filtration apparatus of this invention. It is a schematic diagram which shows the AA cross section of FIG. It is a figure which shows the vertical pleat filter as a filter used for this invention. It is a cross-sectional schematic diagram which shows the structural example of another liquid filtration apparatus of this invention. It is a schematic diagram which shows the structural example of the nozzle used for this invention. It is a figure which shows the horizontal pleat filter as a filter used for this invention.

  A configuration of a liquid filtration device according to the present invention will be described with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element. The present invention is not limited to these, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

  FIG. 1 is a diagram showing an example of a liquid filtration device according to the present invention, and schematically shows a longitudinal section of the device. FIG. 2 is a schematic diagram showing the AA cross section in FIG.

  A cylindrical filter 10 is housed in the case 30. The side surface (cylindrical surface) of the filter 10 is configured by a filtration membrane, and the upper surface and the lower surface are each sealed with a lid plate to which piping can be connected. As shown in FIG. 3, the filtration membrane is a vertical pleated filter having a crease parallel to the central axis C so as to repeat peaks and valleys in the radial direction of the cylinder. This filter is formed by alternately folding a band-like planar base material into a so-called pleated shape, and connecting them in a cylindrical shape.

  In the filter 10, a rotating member 20 connected to a processing liquid channel 41 for supplying a processing liquid into the filter cylinder is housed. The rotary member 20 is connected to the liquid flow path 41 to be processed by a rotary joint 22 and can be rotated about a cylindrical center by a motor (not shown). The rotating member 20 includes a liquid nozzle 21 to be processed on the cylindrical side surface thereof, and is provided so as to eject the liquid to be processed toward the inner surface of the filter membrane of the filter 10. In the drawing, the rotating member 20 is shown as a cylinder with a large radius, but the present invention is not limited to this. It is necessary for the tip of the liquid nozzle 21 to be processed to have a positional relationship such that the liquid to be processed can be ejected and cleaned on the inner surface of the filter 10, and the size of the rotating member 20 and the liquid nozzle 21 to be processed is large. The relationship can be designed in consideration of the ease of rotation and the like. A plurality of liquid nozzles to be processed may be provided.

  An exhaust liquid channel 42 is connected to the bottom surface of the filter 10. A filtrate flow path 43 is connected to the bottom surface of the case 30.

  The function of filtration in the above configuration will be described. The liquid to be processed supplied from the liquid flow path 41 to be processed is guided from the rotating member 20 to the liquid nozzle 21 to be processed, and ejected toward the inner surface of the filter membrane of the filter 10. The liquid to be treated is filtered by the filtration membrane and flows to the outside of the filter 10. In addition, a part of the liquid to be treated is discharged outside from the discharge liquid passage 42 without being filtered. The inner surface of the filtration membrane is cleaned by utilizing the force of the liquid to be treated ejected on the inner surface of the filtration membrane, and the washed turbid components and the like are mixed with the discharged liquid and discharged from the discharged liquid passage 42. In addition, since the liquid nozzle 21 is cleaned while rotating the inner surface of the cylindrical filtration membrane, the entire filtration membrane is sequentially washed. Such an operation makes it difficult for the filter to be clogged and enables long-time filtration. The filtrate flowing out of the filter 10 is taken out from the inside of the case 30 through the filtrate channel 43.

  FIG. 4 is a diagram showing an example of another liquid filtration device according to the present invention, and schematically shows a longitudinal section of the device. The difference from the example of FIG. 1 is the structure of the filter and the configuration of the rotating member and nozzle corresponding thereto.

  A cylindrical filter 11 is housed in the case 30. The side surface (cylindrical surface) of the filter 11 is configured by a filtration membrane, and the upper surface and the lower surface are each sealed with a lid plate to which piping can be connected. As shown in FIG. 6, the filtration membrane is a horizontal pleated filter having a fold line perpendicular to the central axis C so as to repeat a mountain and valley in the radial direction of the cylinder. This filter is formed by alternately folding a band-like planar base material into a so-called pleated shape, and connecting them in a cylindrical shape.

  In the filter 11, a rotating member 23 connected to a processing liquid flow path 41 for supplying a processing liquid into the cylinder of the filter is accommodated. The rotary member 23 is connected to the liquid flow path 41 to be processed by a rotary joint 25, and can be rotated about a cylindrical center by a motor (not shown). The rotating member 23 includes a liquid nozzle 24 to be processed on the cylindrical side surface thereof, and is provided so as to eject the liquid to be processed toward the inner surface of the filter membrane of the filter 11. It is necessary that the tip of the liquid nozzle 24 to be processed be provided in such a positional relationship that the liquid to be processed can be ejected and cleaned on the inner surface of the filter 11, and the size of the rotating member 23 and the liquid nozzle 24 to be processed is large. The relationship can be designed in consideration of the ease of rotation and the like.

  FIG. 5 shows a structural example of the rotating member 23. A plurality of liquid nozzles 24 to be processed are provided on the cylindrical side surface of the rotating member 23. Since the pleats of the filter 11 have a structure in which unevenness is repeated in the cylindrical axis direction, a plurality of liquid nozzles 24 to be processed are provided in positions corresponding to the folds in the cylindrical axis direction, and are sequentially dispersed without being densely arranged in the cylindrical direction. It is provided.

  An exhaust liquid passage 42 is connected to the bottom surface of the filter 11. A filtrate flow path 43 is connected to the bottom surface of the case 30.

  The function of filtration in the above configuration will be described. The liquid to be processed supplied from the liquid pipe 41 to be processed is guided from the rotating member 23 to the liquid nozzle 24 to be processed, and jetted toward the inner surface of the filter membrane of the filter 11. The liquid to be treated is filtered by the filtration membrane and flows to the outside of the filter 11. In addition, a part of the liquid to be treated is discharged outside from the discharge liquid passage 42 without being filtered. The inner surface of the filtration membrane is cleaned by utilizing the force of the liquid to be treated ejected on the inner surface of the filtration membrane, and the washed turbid components and the like are mixed with the discharged liquid and discharged from the discharged liquid passage 42. Further, since the liquid nozzle 24 is cleaned while rotating the inner surface of the cylindrical filtration membrane, the entire filtration membrane is sequentially washed. Such an operation makes it difficult for the filter to be clogged and enables long-time filtration. The filtrate flowing out of the filter 11 is taken out from the inside of the case 30 through the filtrate channel 43.

  Further, in this configuration, since the liquid nozzles 24 to be treated correspond to the pleats of the filter, the cleaning effect is high. In addition, the change in washing pressure in the direction across the pleat is less likely to occur due to the rotation of the nozzle. Can be expected.

  A porous resin sheet is used for the base material of the filter 10 or the filter 11. Examples of materials include polyester, nylon, polyethylene (PE), polypropylene (PP), polyurethane (PUR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), etc. A porous structure such as a nonwoven fabric is used. In the ballast water treatment, a non-woven fabric made of polyester such as polyethylene terephthalate is particularly preferably used because a high flow rate treatment is performed. Moreover, as an example of dimensions, the outer diameter of the pleated filter is 700 mm, the axial length is 320 mm, the height as an effective area is 280 mm, the pleat depth is 70 mm, and the number of pleats is 420 folds. It is possible to change the area or use a plurality of filters in parallel.

  The rotation of the rotating member 20 or the rotating member 23 by the motor has an advantage that the rotation speed can be arbitrarily set and changed. The number of revolutions may be constant, or may be arbitrarily determined artificially, but is more preferably controlled according to the state of filtration. It is preferable to provide a detection unit for detecting the state or flow rate of filtered water and perform control so as to change the number of rotations according to detection information. Specific examples of the filtrate water detection unit include a filtrate water flow rate detection unit, a filtrate water pressure detection unit, and a turbidity detection unit.

  The above liquid filtration device can be suitably used as a ballast water treatment device used in ships. Many ballast water treatment apparatuses are composed of a filtration device portion and a sterilization unit using means such as ultraviolet rays, and the present invention can be applied as a filtration device unit. Ballast water treatment requires 10 to 20 tons / hour, and moreover 100 tons / hour of treatment of seawater in as short a time as possible, so that the enlargement of the filter and continuous washing are required. This device can be realized by a relatively simple structure.

  Since the filtration device of the present invention is capable of continuous operation with a stable and high permeation flow rate by rotary washing, brackish water and seawater use such as seawater desalination and ballast water, or sewage, domestic wastewater, industrial wastewater, etc. In the treatment, it can be suitably used for pre-filtration treatment for removing foreign substances, dust and microorganisms in water. Moreover, since it is excellent in water treatment and concentration treatment of high turbidity and high SS (Suspended Solid), it can also be applied to the field of valuable resources recovery such as food.

10, 11 Filter 20, 23 Rotating member 21, 24 Processed liquid nozzle 22, 25 Rotary joint 30 Case 41 Processed liquid flow path 42 Drained liquid flow path 43 Filtrate flow path

Claims (2)

A filter having a filtration membrane arranged in a cylindrical shape;
A case provided to accommodate the filter;
A liquid flow path for supplying a liquid to be processed to the inside of the cylinder of the filter;
A filtrate flow path for taking out the filtrate filtered by the filter to the outside of the case;
A ballast water treatment device comprising a liquid filtration device comprising a drain liquid flow path for taking out the liquid to be treated that has not been filtered by the filter from the inside of the cylinder of the filter to the outside,
A liquid nozzle to be processed provided to eject the liquid to be processed from the liquid flow path to be processed toward the inner surface of the filter membrane of the filter;
The liquid nozzle to be treated is configured to rotate around the cylindrical axis of the filter ,
The ballast water treatment apparatus , wherein the filtration membrane is a horizontal pleated filter having a pleated shape in which a plurality of peaks and valleys are continuous so as to form a fold in a direction perpendicular to the cylindrical axis . A plurality of the liquid nozzles to be processed are provided, and the plurality of liquid nozzles to be processed are provided apart from each other in the direction of the cylindrical axis and in the circumferential direction around the cylindrical axis ,
The ballast water treatment apparatus according to claim 1 , wherein the plurality of liquid nozzles to be treated are arranged in accordance with an interval between the pleated pleats .

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