JP2010207795A - Filtration unit, and ballast-water production apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration system for use in a compact ballast-water production apparatus that can return plankton living in the sea overboard without harming them to an extent practicable and can keep the treatment cost low. <P>SOLUTION: The filtration system 1 for use in a ballast-water production apparatus in a ship S includes a filtration unit 4 that filtrates raw water RW taken into the ship S and supplies a ballast tank 6 with the filtrated water, a gas supply passage 12 that supplies a depth filter 10 formed of a filtration membrane disposed in the filtration unit 4 with compressed air A to clean the same, and a discharge passage 14 that is connected to the filtration unit 4 and discharges the compressed air A having cleaned the depth filter 10 to the outside of the ship S together with the raw water RW in the depth filter 10, with the pore diameter of the filtration membrane constituting the depth filter 10 being 1 to 25 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for producing ballast water mounted on a ship such as a cargo ship.

  For example, when a ship, particularly a cargo ship, is not loaded, a measure is taken to stabilize the hull by loading seawater or the like into a ballast tank provided in the ship in order to lower the center of gravity of the ship. Ballast water is discharged out of the ship when loading cargo at the port where it stops, but on ocean-going ships, aquatic organisms contained in the ballast water travel between countries and point out problems that affect ecosystems as alien species. Has been.

  In recent years, in order to solve such problems related to ballast water, international efforts have been made for ballast water discharge regulations. Specifically, it regulates the number of plankton (mainly zooplankton), 10 to 50 μm plankton (mainly phytoplankton) and fungi (E. coli, enterococci, etc.) contained in ballast water. is there. Treatment methods to satisfy these regulations usually combine filtration, mechanical treatment such as cavitation that kills plankton by high-speed, high-pressure jet flow, and chemical treatment that uses chemicals, ozone, etc. (For example, Non-Patent Document 1).

Maritime General Magazine Bimonthly Compass September 2007, pages 32-39

  In the conventional ballast water production apparatus described above, the pore size of the filter for filtration is about 50 μm which is relatively large. This is because clogging is likely to occur when the hole diameter is small, and it is necessary to increase the filtration area of the filter in order to avoid this, so that the apparatus becomes large and disadvantageous for mounting the ship. Therefore, plankton having a size of 50 μm or less is treated by cavitation in which seawater is sprayed on the screen at high speed and high pressure to crush plankton, or by drug administration.

  However, in the treatment by cavitation, seawater is blown at high speed and high pressure, so the power becomes excessive and the number of plankton is reduced more than necessary, which may affect the marine ecosystem on the ballast water loading side. is there. Moreover, when processing plankton with a chemical | medical agent etc., a lot of chemical | medical agents are needed, and the processing cost of each time will become expensive.

  The present invention has been made in view of the above-described problems, and is capable of removing particulates and reducing the initial introduction cost and maintenance management cost as low as possible, and damaging plankton living in the sea as much as possible. It is an object of the present invention to provide a ballast water production apparatus that can be returned to the outside of the ship without any problem and that is small in size and can keep processing costs low.

  In order to achieve the above object, a filtration unit according to the present invention is a filtration unit comprising a filter medium and a casing that accommodates the filter medium, and the casing supplies a raw water supply port that supplies raw water to the filter medium, and a filtration A water outlet, a fluid supply port for supplying a backwashing fluid to the filter medium, and a discharge port for discharging the fluid and the raw water from which the filter medium has been backwashed, wherein the filter medium has a depth of 1 to 25 μm. It is a filter. As the fluid for backwashing, a gas or a liquid is used, preferably a gas, and more preferably an inert gas such as air or nitrogen.

The pore diameter is defined as follows. A solution having 10,000 particles / L of water having a constant diameter, preferably spherical polystyrene or glass beads added in water, is added to a depth filter (outer diameter 60 mm, inner diameter 30 mm, length 250 mm) at 25 ° C. and 1.0 m ³ / hr. Measure the number of particles that have passed through the depth filter with an optical counter, and divide the difference in the number of particles present in the liquid before and after the water flow by the number of particles present in the liquid before the water flow. The obtained collection rate (R%) is measured for a plurality of particles, and the value of the diameter (S) of the particles with R of 80 is obtained in the following approximate expression (1) based on the measured values. Is the hole diameter.
R = 100 / (1−m × exp {−a × log (S)}) (1)
Here, m and a are constants determined by the properties of the depth filter.
For example, when the particle diameter is 1 μm, the liquid added with spherical polystyrene fine particles (10,000 particles / L) is passed through a depth filter (outer diameter 60 mm, inner diameter 30 mm, length 250 mm) under the above conditions. Measurement is possible.

  According to this configuration, since the depth filter having a pore diameter of 1 to 25 μm is used as the filter medium, small plankton can be removed and the initial introduction cost can be suppressed as compared with the case of using the surface filter. In addition, by performing reverse flow cleaning, the filtration performance of the filter medium can be recovered and used, so the frequency of replacement of the filter medium can be reduced, and maintenance costs can be reduced.

  In the present invention, the fluid supply port and the filtered water outlet are preferably the same. According to this configuration, the fluid supply port and the filtered water outlet can be shared, and the configuration can be simplified.

  In the present invention, it is preferable that the filter medium is formed by fixing both ends of a plurality of filters with a fixing plate. According to this configuration, by combining a plurality of depth filters, the filtration area is increased, and since the plurality of depth filters become one subunit by integration, the filter medium can be easily replaced.

  In this invention, you may arrange | position so that the said filter medium may incline with the inclination-angle of 20-70 degrees diagonally downward toward the said filtrate water outlet. According to this configuration, since the side opposite to the filtered water outlet in the filtration unit is high, for example, when filtering raw water after backwashing with gas, the gas in the housing is likely to escape from the opposite side, resulting in filtered water. The risk of air contamination is reduced. In addition, if the tilt angle is too large, the vertical dimension of the filtration unit will increase, so a large space for extracting the filter medium is required above the filtration unit during maintenance such as removal, and if it is too small, the filtration unit The fluid inside is difficult to escape.

  In this invention, it can also arrange | position so that the said filter medium may incline at the inclination angle of 20-70 degrees diagonally upward toward the said filtrate water extraction opening. According to this configuration, since the opening end of the depth filter located on the filtered water outlet side opens obliquely upward, air near the closed end of the lower depth filter escapes from the opening end. Air can be prevented from remaining in the interior, and the entire depth filter can be used for efficient filtration.

  In this invention, it is preferable that the said discharge port is provided above the said raw | natural water supply port. According to this configuration, when the raw water is supplied into the filtration unit at the initial operation or after the backwashing is performed with gas, the gas in the filtration unit is smoothly discharged when performing so-called “air bleeding” in the unit. Is done.

  Moreover, the ballast water production apparatus according to the present invention is an apparatus that has the filtration unit according to the present invention and supplies the filtered water taken out from the filtration unit as ballast water to a ballast tank of a ship, wherein the filtration unit The fluid supply passage connected to the fluid supply port in the filter unit for supplying fluid for cleaning the filter medium and the fluid connected to the discharge port in the filtration unit for cleaning the filter medium together with the raw water in the filtration unit And a discharge passage for discharging to the outside.

  According to this configuration, since the depth of the depth filter forming the filter medium is 1 to 25 μm, most of the plankton can be captured and discharged outside the ship, and the marine ecology on the ballast water loading side In addition to breaking the system, there is no need for cavitation and drug administration for treating plankton as in the prior art, so that less power is consumed and the amount of drug used is reduced. As a result, a small system with a low processing cost can be constructed. Moreover, since the filter medium is backwashed, the filter medium can be recovered and used, and the processing cost can be further reduced.

  The method for producing filtered water according to the present invention is a method for producing filtered water by filtering raw water with a filter medium, supplying a fluid from the filtered water side to the filter medium while supplying the raw water to the filter medium, A backwashing process for discharging together with the raw water is provided.

  According to this configuration, since the backwashing is performed, the filtration performance of the filter medium is recovered, so that the maintenance cost can be reduced. In addition, since the raw water is always supplied to the filtration unit even during the backwashing, the backwashing fluid can be smoothly drained without flowing back to the raw water supply side.

  In the present invention, it is preferable to use a depth filter having a pore diameter of 1 to 25 μm as the filter medium. Unlike a surface filter that collects the substance to be filtered only on the surface of the filter, the depth filter can collect the substance to be filtered in the entire thickness direction of the filter. There will be no clogging.

  The method for producing ballast water according to the present invention is a ballast water production method using the ballast water production apparatus of the present invention, and the supply of filtered water from the filter medium to the ballast tank and the supply of fluid to the filter medium are stopped. In a state, the raw water is supplied to the filtration unit in a state where the preparation process of discharging the fluid together with the raw water from the outlet through the filtration unit, and the discharge of the raw water from the filter medium and the fluid supply to the filter medium are stopped, While supplying the filtered water to the filtration medium and supplying the filtered water to the ballast tank, while supplying the raw water to the filter medium, the fluid is supplied from the filtered water side to the filter medium. And a backwashing process for discharging the raw water from the discharge port to the outside of the ship through the discharge passage.

  According to this configuration, plankton living in the sea can be returned to the outside of the ship without damaging it as much as possible, and the processing cost can be kept low with a small size. In addition, since raw water is always supplied to the filtration unit, it is possible to avoid sudden pressure fluctuations in the passage and to prevent occurrence of water hammer. Furthermore, since the raw water is supplied to the filtration unit in the backwashing process, the backwashing fluid can be smoothly drained without flowing back to the raw water supply side.

According to the filtration unit and the filtered water production method of the present invention, by performing backflow cleaning, the filtration performance of the filter medium can be recovered and used, and maintenance costs can be reduced. In addition, since the raw water is always supplied to the filtration unit even during the backwashing, the backwashing fluid can be smoothly drained without flowing back to the raw water supply side.
Further, according to the ballast water production apparatus and the ballast water production method of the present invention, most of the plankton can be captured while keeping the marine ecosystem on the ballast water loading side in addition to consuming power. The amount of electric power and the amount of medicine used can be reduced, and as a result, a small system with a low processing cost can be constructed. Further, the processing cost can be further reduced by recovering the filtration performance of the depth filter.

It is a systematic diagram of the ballast water manufacturing apparatus provided with the filtration unit concerning a 1st embodiment of the present invention. It is an expanded sectional view of a filtration unit same as the above. It is a driving | operation process table | surface of a filtration system same as the above. It is the graph which showed the relationship between the supply flow rate of raw | natural water when changing the hole diameter of a depth filter, and a pressure loss. It is a perspective view of the filtration unit concerning a 2nd embodiment of the present invention. It is a top view of the stationary plate of the filtration unit. It is a systematic diagram of the ballast water manufacturing apparatus which concerns on 3rd Embodiment of this invention. It is a systematic diagram when filtering with one filtration unit of the apparatus. It is a systematic diagram when filtering with the other filtration unit of the same apparatus. It is a perspective view of the filtration unit concerning a 4th embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic system diagram of a ballast water production apparatus for a ship provided with a filtration unit according to the first embodiment of the present invention. The ballast water production apparatus 1 is installed in the ship S, and includes a ballast pump 2 that takes the raw water RW into the ship S and a filtration unit 4 that filters the raw water RW taken into the ship. The filtration unit 4 includes a raw water passage 5 to which the raw water RW is supplied by the ballast pump 2, a water supply passage 8 for supplying the filtrate FW from the filtration unit 4 to the ballast tank 6 installed in the ship S, and a filtration unit 4 is connected to a discharge passage 14 for discharging raw water RW together with compressed air A, which will be described later, to the outside of the ship, and a gas supply passage 12 for supplying the compressed air A to the filtration unit 4 is connected to the water supply passage 8. Thereby, with respect to the existing ballast water production apparatus already mounted on the ship S, the filtration unit is replaced with the filtration unit 4 of the present invention, and the gas supply passage 12 is further connected to the existing water supply passage. The present invention can be easily applied to this ballast water production apparatus.

  Each passage 5, 8, 12, 14 is formed by piping. The filtration unit 4 houses a depth filter 10 which is a filter medium forming a filtration membrane in a cylindrical housing 9. In the present embodiment, the ballast pump 2 is mounted on the ship, but may be provided outside the ship, for example, may be installed in a port.

  The raw water passage 5 is connected to a first automatic opening / closing valve MV1 that functions as a raw water flow rate adjusting valve, and is primary between the first automatic opening / closing valve MV1 and the filtration unit 4 in the raw water passage 5, that is, to the primary side of the filtration unit 4. A pressure sensor P1 is provided. The water supply passage 8 is connected to a second automatic opening / closing valve MV2 that functions as a water supply valve for the filtered water FW, and between the second automatic opening / closing valve MV2 and the filtration unit 4 in the water supply passage 8, that is, the secondary side of the filtration unit 4. Is provided with a secondary pressure sensor P2. Furthermore, a mixer 26 is provided on the upstream side of the ballast tank 6 in the water supply passage 8, and the sterilizing chemical and filtered water FW introduced from the chemical tank 28 are agitated by the mixer 26. The chemical | medical agent thrown in is hypochlorous acid and a peroxide, for example. Moreover, it may replace with the method of throwing in a chemical | medical agent, and may use the other well-known sterilization means for manufacturing the treated water corresponding to the standard prescribed | regulated by the ballast water management convention. Specific examples include a method of contacting with ozone and a method of irradiating with ultraviolet rays.

  The gas supply passage 12 is connected to a third automatic opening / closing valve MV3 that acts as a compressed air introduction valve, and the drainage passage 14 is connected to a fourth automatic opening / closing valve MV4 that acts as a drainage valve. One end of the gas supply passage 12 is connected to an air compressor (not shown), and the other end is connected to the secondary side below the filtration unit 4. The other end of the gas supply passage 12 may be connected to the vicinity of the filtration unit 4 in the water supply passage 8, more specifically, between the filtration unit 4 and the secondary pressure sensor P2. Driving of the ballast pump 2 and the first to fourth automatic opening / closing valves MV <b> 1 to MV <b> 4 is controlled by the controller 30. The outputs of the primary pressure sensor P1 and the secondary pressure sensor P2 are input to the controller 30.

  As the air compressor, one installed on the ship for another purpose may be used, or a dedicated one may be installed. In addition, as each of the automatic opening / closing valves MV1 to MV4, an air drive valve, an electric valve, an electromagnetic valve, a manual valve that does not use a controller, or the like is used.

  The depth filter 10 has a hollow cylindrical shape with one end opened and the other end closed with a closing member 13, and the hollow end of the depth filter 10 is directed toward the filtered water outlet 16 with the opening end 10 a being one end thereof. 11 is communicated with the filtered water outlet 16. When the raw water RW passes through the depth filter 10 in the radial direction, foreign matters are captured by the pores inside the filter, and filtered water FW is obtained. The depth filter 10 is also detachably housed in the housing 9 of the filtration unit 4 so that the open end 10a is below the closed end 10b which is the other end, that is, the filtration unit 4 is connected to the filtered water outlet. It is arrange | positioned so that it may incline diagonally downward toward 16. FIG. The inclination angle α, which is an angle formed by the center line C in the longitudinal direction of the depth filter 10 and the horizontal plane H, is preferably 20 to 70 °, and more preferably 30 to 60 °.

  As shown in FIG. 2, which is an enlarged cross-sectional view of the filtration unit 4, a filtered water outlet 16 is provided in the lower end wall 9 a of the inclined filtration unit 4 and the housing 9 of the filtration unit 4. A raw water supply port 18 is provided at a lower portion of the peripheral wall 9b near the one end wall 9a, and a discharge port 22 is provided above the raw water supply port 18 and at an upper portion of the peripheral wall 9b of the housing 9 near the other end wall 9c. .

  The raw water passage 5 is connected to the raw water supply port 18, the water supply passage 8 is connected to the filtered water outlet 16, and the drainage passage 14 is connected to the discharge port 22. The filtered water outlet 16 is connected to the gas supply passage 12, and the filtered water outlet 16 also serves as the gas supply port 24 of the compressed air A in the filtration unit 4, so that the gas supply port 24 is compressed. It is provided at a position lower than the discharge port 22 which is the outlet for the air A and the raw water RW. Thereby, the air lift effect by the pressure of the compressed air A is utilized, that is, the raw water RW in the drainage passage 14 is pushed up by the air and the raw water RW is drained, so that the raw water RW and the compressed air A can be discharged smoothly. it can. The raw water supply port 18 and the discharge port 22 are provided on the primary side of the depth filter 10, and the filtered water outlet 16 is provided on the secondary side.

  The depth filter 10 is an external pressure type cylindrical filter and has a U-shaped longitudinal section. Examples of the depth filter 10 include what is called a laminated type in which synthetic fibers or chemical fibers are welded / formed in the form of a web, non-woven fabric, paper, woven fabric or the like and processed into a cylindrical shape. As the synthetic fiber, polyolefin, polyester, heat-meltable polymer such as nylon or ethylene vinyl alcohol copolymer, or polymer such as polyvinyl alcohol or polyacrylonitrile can be used. Among these, when backflow cleaning with gas is performed, polyolefin and polyester, specifically, polypropylene are preferable from the viewpoint of liquid drainage at the time of filter replacement. The filter preferably has a structure in which the fiber density and fineness are changed in the thickness direction, and the fiber density is low or the fineness is large on the outside (raw water inflow side) of the filter. The depth filter 10 includes a so-called thread wound filter in which filaments and spun yarns are spirally wound, and a so-called resin molded type that is a resin molded body such as a sponge.

  The pore diameter of the filtration membrane is 1 to 25 μm, more preferably 1 to 10 μm. If the pore diameter is too small, clogging occurs and pressure loss increases. If the hole diameter is too large, small plankton will pass through, and in order to reduce this, additional means such as cavitation is required, which increases the cost of producing ballast water.

  The depth filter 10 can be backwashed in the filtration unit 4 and can be used without increasing the differential pressure during filtration by recovering the filtration performance by backwashing. In this embodiment, the backwashing is performed by compressed air A supplied from a compressor (not shown) through the gas supply passage 12 (FIG. 1), and the supply pressure of the compressed air A from the gas supply port 24 is The pressure is 0.05 to 0.2 MPa higher than the indicated pressure of the primary pressure sensor P1. The fluid used for backwashing may be a gas other than air, such as nitrogen, or a liquid such as fresh water or filtered seawater.

  Next, the operation method of the ballast water production apparatus, that is, the filtered water production method using the filtration unit according to the present embodiment will be described with reference to FIGS. 1 and 3. As shown in FIG. 3, the operation method of the ballast water production apparatus includes an air venting process, a first switching process, a filtering process, a second switching process, a third switching process, and a backwashing process, which are preparatory processes for filtration.

  When the ballast water production apparatus 1 is operated by operating a start button (not shown) installed in the controller 30, the ballast pump 2 is activated first, and the first automatic open / close valve MV1 and the fourth automatic open / close valve MV4 are opened. To enter the air venting process. In the air venting process, the second automatic open / close valve MV2 and the third automatic open / close valve MV3 are closed, and the supply of filtered water FW from the depth filter 10 to the ballast tank 6 and the supply of compressed air A to the depth filter 10 are stopped. In the state, the raw water RW flows through the discharge passage 14 through the filtration unit 4 and is discharged to the outside of the ship, whereby the raw water passage 5 and the filtration unit 4 are vented.

  Next, the second automatic opening / closing valve MV2 is opened to enter the first switching step. In the first switching step, in a state where the supply of the compressed air A to the depth filter 10 is stopped, the raw water RW is supplied to the discharge passage 14 and the filtered water FW is supplied to the water supply passage 8 through the filtration unit 4.

  Subsequently, the fourth automatic opening / closing valve MV4 is closed and the filtration process is started. In the filtration step, the raw water RW is supplied to the filtration unit 4 in a state where the drainage from the depth filter 10 and the compressed air supply to the depth filter 10 are stopped, and the filtrate FW is sent to the water supply passage 8. At this time, the raw water RW passes through the filtration membrane of the depth filter 10 from the outside of the depth filter 10 and flows into the hollow portion 11, thereby removing foreign substances in the raw water RW and filtering. The filtered water FW is supplied to the ballast tank 6 through the water supply passage 8.

  Next, the fourth automatic opening / closing valve MV4 is opened to enter the second switching step. In the second switching step, in a state where the supply of the compressed air A to the depth filter 10 is stopped, the raw water RW is supplied to the filtration unit 4 so that the filtered water FW flows through the water supply passage 8 and the raw water RW is discharged into the discharge passage 14. Shed.

  Subsequently, the second automatic opening / closing valve MV2 is closed and the third switching step is entered. In the third switching step, the raw water RW is caused to flow through the discharge passage 14 in a state where supply of the filtered water FW from the depth filter 10 to the ballast tank 6 and supply of the compressed air A to the depth filter 10 are stopped. In this way, the supply of the filtrate FW from the depth filter 10 is stopped to prepare for the start of the supply of the compressed air A in the direction opposite to the flow direction of the filtrate FW in the next backwashing step.

  Next, with the second automatic opening / closing valve MV2 closed, the third automatic opening / closing valve MV3 is opened and the back washing process is started. In the backwashing process, the compressed air A is supplied to the hollow portion 11 of the depth filter 10 while supplying the raw water RW to the filtration unit 4 while the supply of the filtered water FW to the ballast tank 6 is stopped. The air A is passed through the discharge passage 14 together with the raw water RW. As a result, the compressed air A passes through the depth filter 10 in the direction opposite to that of the filtration step, and the foreign matter adhering to the depth filter 10 and the foreign matter accumulated in the housing 9 are led out of the filtration unit 4, and the discharge passage 14 To the outside of the ship S.

  When the back washing process is completed, the third automatic opening / closing valve MV3 is closed and the process returns to the air bleeding process. Thereafter, this loop is repeated. The duration of the bleed process is variably set by a time limit device such as a timer. The set time varies depending on the scale of the processing equipment, but is, for example, about several seconds to 1 minute. The first, second and third switching steps are for a very short time, for example, several seconds, and are also variably set by a time limit device such as a timer. Thus, it is possible to avoid sudden pressure fluctuations in the passage by passing through the first, second and third switching steps before entering the filtration step and the backwashing step. Although the time of a filtration process and a backwash process changes with the water quality of raw | natural water and the scale of an installation, it is about 10 minutes, for example, and this is also variably set by a time limit apparatus like a timer. The transition from the filtration step to the second switching step may be performed when the differential pressure ΔP (= P1−P2) between the primary pressure sensor P1 and the secondary pressure sensor P2 becomes larger than a specified value. .

  During the filtration process, the controller 30 constantly monitors the differential pressure ΔP. When the differential pressure ΔP exceeds the alarm value H1, an alarm such as a buzzer is issued to call attention. At this time, the water treatment apparatus 1 continues to operate. Further, when the differential pressure ΔP increases and exceeds the emergency stop value H2, an alarm such as a bell is issued, and the water treatment apparatus 1 is urgently stopped. Specifically, the controller 30 stops the ballast pump 2 and closes all the automatic opening / closing valves MV1 to MV4.

  Sudden pressure changes and flow velocity changes not only damage plankton, but also water hammers (water hammer) occur in the parastump pump 2, the automatic open / close valves MV1 to MV4, and the passages 5, 8, 12, and 14. However, as in the operation method of FIG. 3, the ballast pump 2 is always operated and the supply of the raw water RW from the ballast pump 2 is not stopped, and the opening / closing timing of each of the automatic opening / closing valves MV1 to MV4 is adjusted. As a result, mild driving can be performed. Further, since the backwashing is performed while the raw water RW is flowing, drainage can be smoothly performed by the discharge pressure of the ballast pump 2 and the air pressure of the compressed air A, and a separate drain pump and drain pipe are not required, and the system can be simplified.

  In the above configuration, since the pore diameter of the filtration membrane forming the depth filter 10 is 1 to 25 μm, it is possible to capture most of the plankton while suppressing pressure loss due to clogging of the filter, and to load the ballast water In addition to not destroying the marine ecosystem on the side, there is no need to perform cavitation and drug administration for treating plankton as in the conventional case, so the power consumption of the power and the amount of drug used can be reduced. As a result, it is possible to construct a ballast water production apparatus that is small and inexpensive. Moreover, since the depth filter 10 is back-washed, the filtration performance of the depth filter 10 can be recovered and used, and processing costs can be further reduced. Furthermore, since the inexpensive depth filter 10 is used, the initial introduction cost can be reduced as compared with the case of using a surface filter that captures foreign matters on the filter surface such as a flat membrane.

  Since the gas supply port 24 and the filtered water outlet 16 are the same, the gas supply port 24 and the filtered water outlet 16 can be shared to simplify the configuration.

  Furthermore, since the filtration unit 4 is arranged so as to incline downward as it goes to the filtrate outlet 16, the side opposite to the filtrate outlet 16 in the filtration unit 4 becomes higher, and the raw water RW is filtered after backflow cleaning with gas. When it does, air A in filtration unit 4 becomes easy to escape, and a possibility that air may mix in filtrate water FW decreases. In addition, if the inclination angle α with respect to the horizontal direction is too large, the vertical dimension of the filtration unit 4 becomes large. Therefore, a large space is required for extracting the depth filter 10 above the filtration unit 4 during maintenance such as removal. If it is too small, the air A in the filtration unit 4 is difficult to escape. Therefore, this inclination angle α is preferably 20 to 70 °.

  Since the discharge port 22 is provided above the raw water supply port 18, the air in the filtration unit 4 is vented by resuming the supply of the raw water at the initial operation when the raw water is supplied for the filtration operation or after backwashing. When performing, the air A in the filtration unit 4 is discharged | emitted smoothly.

  Furthermore, according to the above operation method, as shown in FIG. 3, the ballast pump 2 is always in operation during the system operation, that is, the raw water RW is always supplied to the filtration unit 4, so Sudden pressure fluctuations can be avoided and the occurrence of water hammer can be prevented. Further, since the raw water RW is also supplied to the filtration unit 4 in the backwashing process, the raw water flow is not caused to flow back into the raw water passage 5 by the supply pressure of the compressed air A and the supply pressure of the raw water RW. Can be drained smoothly on top.

  In addition, unlike a surface filter that collects the material to be filtered only on the surface of the filter, the depth filter can collect the material to be filtered in the entire thickness direction of the filter. There is no time clogging.

A verification experiment was performed using the depth filter 10 in the present embodiment. The raw water is seawater, and the supply pressure and flow rate of the raw water are 0.03 MPa and 0.037 m ³ / min, respectively. Compressed air is used as the backwash fluid, and the supply pressure and flow rate of the compressed air are 0.13 MPa and 0.4 Nm ³ / min, respectively. The depth filter used had a length of 25 cm and a pore size of 1 μm and 25 μm. Further, the axis of the depth filter was arranged to be inclined by 45 ° with respect to the horizontal plane.

Verification 1: Initial pressure loss Table 1 shows the pressures at the primary and secondary sides of the depth filter when raw water is supplied in depth filters with pore sizes of 0.5 μm, 1 μm and 25 μm when the raw water temperature is 25 ° C. FIG. 4 is a graph showing the relationship between the raw water supply flow rate and the pressure loss. As is clear from Table 1 and FIG. 4, the pressure loss was small in the 1 μm and 25 μm depth filters, but the pressure loss was extremely large in the 0.5 μm depth filter, and almost no raw water flowed. Accordingly, the pore diameter of the depth filter is preferably 1 μm or more.

Verification 2: Backwashing effect Table 2 shows the state of the depth filter when the continuous filtration operation and the filtration operation / backwashing operation are alternately performed for each of the depth filters having a pore diameter of 1 μm and 25 μm. ). In the alternate operation of filtration and backwash, the filtration operation and the backwash operation were alternately repeated every 5 minutes. When the continuous filtration operation was performed, the differential pressure increased in about 2 hours for the 25 μm depth filter and in about 40 minutes for the 1 μm depth filter, and the depth filter was blocked. In the alternate operation of filtration and backwashing, in either the 1 μm or 25 μm depth filter, the differential pressure did not increase after 5 hours of continuous operation, and the depth filter was not blocked.

Verification 3: Water quality of filtered water Table 3 shows the number of particles according to size (the number of particles in water) contained in 1 ml of raw water and filtered water and the removal rate in each depth filter having a pore size of 1 μm and 25 μm. The denominator of each data represents the number of underwater particles in raw water, the numerator represents the number of underwater particles in filtered water, and the numerical value in parentheses represents the removal rate. In a depth filter having a pore size of 25 μm, about 96% of particles having a particle size of 25 μm or more are removed, and about 88% of particles of 10 μm or more are removed, and 60% or more of particles having a pore size of 1 μm or more are removed. Further, in the depth filter having a pore diameter of 1 μm, 99% or more of particles having a particle diameter of 25 μm or more, about 94% of particles of 10 μm or more are removed, and 90% or more of particles having a diameter of 1 μm or more are removed.

Verification 4: Drug Input Table 4 shows the concentration of drug (hypochlorous acid) necessary to dispose of bacteria and microorganisms remaining in the filtered water after passing through the depth filter 10. “None” indicates that no filtration is performed, that is, raw seawater, and the depth filter 10 having a pore diameter of 50 μm is used for conventional ballast water production. As can be seen from Table 4, when the pore diameter is 30 μm, the effect is less than that of the conventional 50 μm, but when the depth filter 10 of 25 μm is used, the concentration is about one third of the conventional 50 μm, In the case of 10 μm, a concentration of 1/8 or less is sufficient. Therefore, the pore diameter of the depth filter is preferably 25 μm or less.

  As can be seen from the result of the verification 1, the depth filter 10 used in the present embodiment has almost no pressure loss even if the hole diameter is 1 μm. Therefore, the projection area of the depth filter 10 is small, and the filtration unit 4 is large. Can be suppressed. Further, as can be seen from the result of verification 2, it can be used repeatedly by performing backwashing. Thereby, the lifetime is remarkably increased. Further, as can be seen from the result of verification 3, the pore diameter is 25 μm, and 90% or more of plankton of 50 μm or more is removed and 80% or more of plankton of 10 μm or more is removed. Further, as can be seen from the result of the verification 4, the pore diameter is set to 25 μm, and the concentration of the medicine can be reduced to one third compared with the case of using a conventional filter having a pore diameter of 50 μm. Therefore, the hole diameter of the depth filter 10 can be set to 1 to 25 μm.

  FIG. 5 is a perspective view showing a filtration unit 4 </ b> A according to the second embodiment of the present invention provided with a plurality of depth filters 10. As in the first embodiment, the filtration unit 4A includes a filter medium 38 and a cylindrical casing 9A that accommodates the filter medium 38. The casing 9A includes a filtrate outlet 16A, a raw water supply port 18A, and a discharge port 22A. And the gas supply port 24A, and the filtrate outlet 16A and the gas supply port 24A are common. The arrangement and functions of the filtered water outlet 16A, the raw water supply port 18A, the discharge port 22A, and the gas supply port 24A are the same as those in the first embodiment.

  A lid 9Ac is provided at the top of the housing 9A so that it can be opened and closed, and a bottom plate 9Ad is provided at the bottom. The bottom plate 9Ad is provided with a circular through hole 52 at a position corresponding to each depth filter 10, and the hollow portion 11 of each depth filter 10 communicates with the filtrate outlet 16A and the gas supply port 24A. In the second embodiment, a subunit in which both ends of a plurality of depth filters 10 are fixed by a fixing plate 40 and integrated is used as the filter medium 38. The fixing means is, for example, fixing with an adhesive, but is not limited thereto. Each depth filter 10 is the same as that of the first embodiment except that one end is not closed by the closing member 13 (FIG. 2), that is, a hollow cylindrical shape having both ends opened. In this embodiment, 19 depth filters 10 are used, but the number of depth filters 10 is not limited to this.

  FIG. 6 is a plan view of the fixed plate 40. The fixed plate 40 is made of, for example, a resin plate, and a circular opening 46 is formed at a position corresponding to each depth filter 10. The diameter of the opening 46 is set smaller than the outer diameter of the depth filter 10. In this embodiment, the fixing plate 40 has a hexagonal shape, but may be another polygonal shape or a circular shape. An engaged groove 48 is formed on one side of the fixed plate 40 and is engaged with the engagement plate 44 of the housing 9A to position the filter medium 38 in the circumferential direction with respect to the housing 9A.

  Next, the assembly method of the filtration unit 4A of 2nd Embodiment is demonstrated using FIG. First, by using an adhesive or the like, the depth filters 10 are integrated by being fixed to the fixing plate 40 so that both ends of the depth filter 10 are aligned with the openings 46, and the filter medium 38 is completed as a subunit.

  Subsequently, the filter medium 38 is inserted into the housing 9A with the engaged groove 48 of the fixing plate 40 shown in FIG. 5 engaged with the engaging plate 44 of the housing 9A. Further, by closing the lid portion 9Ac, the filter medium 38 is sandwiched and firmly supported by the lid portion 9Ac and the bottom plate 9Ad.

  Here, since the upper portion of the depth filter 10 is closed by the lid portion 9Ac, the filtrate FW in the hollow portion 11 of the depth filter 10 is led out from the filtrate outlet 16A through the through hole 52 of the lower bottom plate 9Ad. Is done. Further, the compressed air A for backflow cleaning introduced into the filtration unit 4A from the gas supply port 24A is guided to the hollow portion 11 of the depth filter 10 through the through hole 52 of the bottom plate 9Ad, and the depth filter 10 is cleaned.

  According to the second embodiment, the same effects as those of the first embodiment can be obtained, and the filter medium 38 is formed by combining the plurality of depth filters 10, so that the filtration area is increased and the filtration is efficiently performed. It can be performed. Furthermore, since the plurality of depth filters 10 are integrated as a subunit, the plurality of depth filters 10 can be easily replaced by replacing the integrated filter medium 38.

  FIG. 7 is a schematic system diagram of a ballast water production apparatus according to the third embodiment. The difference from the embodiment of FIG. 1 is that two first and second filtration units 4B and 4C are provided, and the other filtration unit 4C (4B) is filtered while being filtered by one filtration unit 4B (4C). The other structures and operations are the same as those of the apparatus shown in FIG. The filtration units 4B and 4C may be the filtration unit 4 of the first embodiment or the filtration unit 4A of the second embodiment.

  In the third embodiment, the raw water passage 5 to which the raw water RW is supplied from the ballast pump 2 branches into two raw water branch passages 5B and 5C, and the first and second raw water branch passages 5B and 5C are respectively the first and second raw water branch passages 5B and 5C. 2 It is connected to the raw water supply ports 18B and 18C of the filtration units 4B and 4C. First and second raw water inflow valves B1 and C1 are provided in the first and second raw water branch passages 5B and 5C, respectively. The water supply passage 8 for sending the filtrate FW to the ballast tank 6 via the mixer 26 and the chemical tank 28 is also branched into two first and second filtration water branch passages 8B and 8C, so that the first and second filtration water branch passages are branched. 8B and 8C are connected to filtered water outlets 16B and 16C of the first and second filtration units 4B and 4C, respectively. First and second filtered water feed valves B2 and C2 are provided in the first and second filtered water branch passages 8B and 8C, respectively.

  The air supply passage 12 for supplying the compressed air A for backflow cleaning also branches into two first and second air branch passages 12B and 12C, and the first and second air branch passages 12B and 12C are the first and second air branch passages 12B and 12C, respectively. The second filtered water branch passages 8B and 8C are connected to the upstream side of the first and second filtered water feed valves B2 and C2, that is, to the filtration units 4B and 4C side. First and second air supply valves B3 and C3 are provided in the first and second air branch passages 12B and 12C, respectively. The discharge passage 14 for discharging the raw water RW in each filtration unit 4B, 4C together with the compressed air A also branches into two first and second discharge branch passages 14B, 14C, and the first and second drainage branch passages 14B, 14C. Are connected to the outlets 22B and 22C of the first and second filtration units 4B and 4C, respectively. First and second discharge valves B4 and C4 are provided in the first and second discharge branch passages 14B and 14C, respectively.

  Also in this embodiment, the ballast pump 2, the ballast tank 6, the mixer 26, the chemical tank 28 and the raw water passage 5, the water supply passage 8, the air supply passage 12, and the discharge passage 14 can use existing ones in the ship, Only the filtration units 4B and 4C according to the present embodiment and each branch pipe connected thereto can be replaced with existing ones. Moreover, as each valve B1-4 and C1-4, an air drive valve, an electric valve, a solenoid valve, or a manual valve that does not use a controller is used.

  Next, the operation method of the ballast water production apparatus of the present embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a system diagram when the first filtration unit 4B performs filtration and the second filtration unit 4C is backwashed. At this time, the first raw water inflow valve B1, the first filtered water feed valve B2, the second raw water inflow valve C1, the second air supply valve C3, and the second discharge valve C4 are open, and the first air supply valve B3, The 1 discharge valve B4 and the second filtered water feed valve C2 are closed. The raw water RW supplied by the ballast pump 2 is supplied to the first and second filtration units 4B and 4C through the first and second raw water branch passages 5B and 5C. The raw water RW supplied to the first filtration unit 4B is filtered by the depth filter 10 and sent from the first water supply branch passage 8B to the ballast tank 6 through the water supply passage 8. On the other hand, the compressed air A supplied from an air compressor (not shown) is supplied to the second filtration unit 4C through the second air branch passage 12C, and the depth filter 10 is backwashed to obtain the second together with the raw water RW. It is discharged out of the ship from the discharge branch passage 14C through the discharge passage 14. Arrow RA in the figure indicates the flow of raw water RW, arrow FA indicates the flow of filtered water FW, and arrow AA indicates the flow of compressed air A.

  FIG. 9 is a system diagram when filtration is performed by the second filtration unit 4C and the first filtration unit 4B is backwashed. At this time, the first raw water inflow valve B1, the first air supply valve B3, the first discharge valve B4, the second raw water inflow valve C1 and the second filtered water feed valve C2 are open, and the first filtered water feed valve B2, The second air supply valve C3 and the second discharge valve C4 are closed. The raw water RW supplied by the ballast pump 2 is supplied to the first and second filtration units 4B and 4C through the first and second raw water branch passages 5A and 5B. The raw water RW supplied to the second filtration unit 4C is filtered by the depth filter 10 and sent from the second water supply branch passage 8C to the ballast tank 6 through the water supply passage 8. On the other hand, the compressed air A supplied from an air compressor (not shown) is supplied to the first filtration unit 4B through the first air branch passage 12B, and the depth filter 10 is backwashed to obtain the first together with the raw water RW. The water is discharged from the discharge branch passage 14B through the discharge passage 14 to the outside of the ship.

  Even if one of the filtration units 4B (4C) is backwashing by alternately repeating the open / closed states of the valves B1 to 4 and C1 to 4 of FIGS. 8 and 9 by a timing device such as a timer, the other The filtration unit 4C (4B) can be used for filtration. In this embodiment, two filtration units 4B and 4C are provided, but three or more may be provided.

  According to the third embodiment, since the first and second filtration units 4B and 4C are cleaned and filtered simultaneously, it is possible to always continue the filtration and to shorten the ballast water production time. Further, even if an abnormality occurs in one filtration unit 4B (4C), ballast water is produced by using the other filtration unit 4C (4B) so as to alternately perform filtration and backwashing. Therefore, the reliability of the entire system is improved.

  FIG. 10 shows a filtration unit 4D of the fourth embodiment. In this embodiment, the cylindrical housing 9D of the filtration unit 4D is composed of a lower end wall 9Da, a peripheral wall 9Db, and an upper end wall 9Dc. It is arranged so as to incline obliquely upward toward the other end wall 9Dc. The inclination angle α, which is an angle formed by the center line C in the longitudinal direction of the depth filter 10 and the horizontal plane H, is preferably 20 to 70 °, and more preferably 30 to 60 °. If the inclination angle α is too large, the vertical dimension of the filtration unit 4D becomes large. Therefore, when performing maintenance such as removal, a large space for extracting the depth filter 10D is necessary above the filtration unit 4D. Air A in the housing 9D is difficult to escape.

  A discharge port 22D connected to the discharge passage 14 in the one end wall 9Da of the housing 9D, a raw water supply port 18D connected to the raw water passage 5 in the vicinity of the one end wall 9Da in the peripheral wall 9Db, and in the vicinity of the other end wall 9Dc in the peripheral wall 9Db. A gas supply port 24D connected to the gas supply passage 12 and a filtered water outlet 16D connected to the water supply passage 8 are formed.

  An annular bottom plate 9Dd is provided below the gas supply port 24D and the filtrate outlet 16D in the peripheral wall 9Db of the housing 9D in the axial direction, and the opening end 10Da of the depth filter 10D is supported by the bottom plate 9Dd. That is, a space S is formed between the other end wall 9Dc and the bottom plate 9Dd in the housing 9D, and the gas supply port 24D, the filtrate outlet 16D, and the opening end 10Da of the depth filter 10D face the space S. The hollow portion 11D of the depth filter 10D communicates with the space S. The depth filter 10D concentric with the housing 9D is also inclined, and is arranged so that the open end 10Da is above the closed end 10Db. Other configurations are the same as those of the first embodiment.

  According to the fourth embodiment, since the opening end 10Da of the depth filter 10D opens obliquely upward, the air in the vicinity of the closed end 10Db of the depth filter 10D is opened when switching from the backwashing process to the air bleeding process. Since the air flows out from the end 10Da, it is possible to prevent air from remaining in the depth filter 10D, and to efficiently perform filtration using the entire depth filter 10D in the filtration process.

  In the fourth embodiment, a plurality of depth filters 10D can be provided as in the second embodiment, and an apparatus with two filtration units 4D can be configured as in the third embodiment. These can also be combined.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing is also included in the scope of the present invention.

1 Ballast water production equipment (filtration system)
4 Filtration unit 6 Ballast tank 8 Water supply passage 9 Housing 10 Depth filter (filter material)
12 Gas supply passage 14 Discharge passage 16 Filtration water outlet 18 Raw water supply port 22 Discharge port 24 Gas supply port 38 Filter medium 40 Fixing plate A Compressed air FW Filtration water RW Raw water

Claims (10)

A filtration unit comprising a filter medium and a housing for housing the filter medium,
The casing has a raw water supply port for supplying raw water to the filter medium, a filtered water outlet, a fluid supply port for supplying backwash fluid to the filter medium, a fluid obtained by backwashing the filter medium, and the raw water Has a discharge port for discharging
A filtration unit in which the filter medium is a depth filter having a pore diameter of 1 to 25 μm.   The filtration unit according to claim 1, wherein the fluid supply port and the filtered water outlet are the same.   The filtration unit according to claim 1 or 2, wherein the filter medium is a unit in which both ends of a plurality of depth filters are fixed with a fixing plate.   The filtration unit according to claim 1, 2, or 3, wherein the filter medium is disposed so as to be inclined obliquely downward toward the filtrate outlet, and the inclination angle is 20 to 70 ° with respect to a horizontal direction.   The filtration unit according to any one of claims 1 to 4, wherein the discharge port is provided above the raw water supply port.   The filtration unit according to claim 1, 2 or 3, wherein the filter medium is disposed so as to be inclined obliquely upward toward the filtrate outlet, and the inclination angle is 20 to 70 ° with respect to a horizontal direction. A device having the filtration unit according to any one of claims 1 to 6, and supplying the filtered water taken out from the filtration unit as ballast water to a ballast tank of a ship,
A fluid supply passage connected to a fluid supply port in the filtration unit and supplying a fluid for cleaning the filter medium;
A discharge passage connected to a discharge port in the filtration unit and discharging the fluid that has washed the filter medium to the outside of the ship together with the raw water in the filtration unit;
A ballast water production apparatus comprising: A method of producing filtered water by filtering raw water with a filter medium,
A filtered water production method comprising a backwashing step of supplying a fluid from a filtered water side to a filter medium while supplying the raw water to the filter medium, and discharging the fluid together with the raw water.   9. The filtered water production method according to claim 8, wherein a depth filter having a pore diameter of 1 to 25 μm is used as the filter medium. A ballast water production method using the ballast water production apparatus according to claim 7,
In a state where supply of filtered water from the filter medium to the ballast tank and supply of fluid to the filter medium are stopped, a preparation step of discharging the fluid together with raw water from the discharge port through the filtration unit;
In a state where the discharge of raw water from the filter medium and the fluid supply to the filter medium are stopped, the raw water is supplied to the filtration unit, and the filtered water is sent to the filtered water outlet,
While supplying the filtered water to the ballast tank, while supplying the raw water to the filter medium, the fluid is supplied from the filtered water side to the filter medium, and this fluid is supplied together with the raw water from the outlet to the discharge passage through the discharge passage. Backwashing process to discharge outside,
A ballast water production method comprising:

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