JP6488368B2 - Water treatment equipment - Google Patents

Description

Cross-reference of related applications

  This application claims the priority of Japanese Patent Application No. 2015-226854, and is incorporated into the description of this specification by reference.

  The present invention relates to a water treatment facility including a relay tank and a filtering device for relaying raw water to be filtered by a filtering device.

  Conventionally, various types of filtration devices are known. For example, a gravity type filtration device as shown in Patent Document 1 below is known.

This type of filtration device has a filter layer in which a granular filter medium is deposited to a certain thickness or more. In the filtration device, the raw water supplied to the upper part of the filter bed passes through the filter bed as a downward flow. And the removal target substance contained in raw | natural water adheres to the said filter medium, and is removed from raw | natural water, when raw | natural water passes a filter layer.
As a water treatment facility that performs raw water filtration using this type of filtration device, the raw water tank that stores the raw water is arranged vertically above the filter layer, and the gravity water causes the raw water tank to be filtered. A type that is supplied with raw water is known.

  As the water treatment facility, there is known a type in which the raw water is not directly supplied from the raw water tank to the filtration device but is once relayed by a relay tank such as a loop seal tank.

Japanese Unexamined Patent Publication No. 2014-188415

  The conventional relay tank has a tank body that relays raw water. The tank body of the relay tank is provided with a raw water inlet into which the raw water flows and a raw water outlet through which the raw water is discharged toward the filtration device. And about the loop seal tank utilized as a relay tank, the structure like a diving dam is formed in the inside so that the inflowed water may turn from a downward flow to an upward flow. That is, the loop seal tank is configured such that when the supply of water stops, the space between the raw water inlet and the raw water outlet is sealed by the water stored therein.

  By the way, when bubbles are mixed in the raw water supplied to the filtering device, the bubbles may deteriorate the performance of the filtering device. For example, in a filtering device including a filter layer on which granular filter media are deposited as described above, if bubbles are mixed in raw water, the bubbles may be trapped in the gaps of the filter media. And raw | natural water cannot penetrate | invade into the location where the bubble is trapped. Therefore, if bubbles exist in the gaps between the filter media, the surface area of the filter media that can be used for attaching the substance to be removed is reduced. In addition, when bubbles are present in the gaps between the filter media, the passing speed of the raw water is increased, and the quality of the filtered water that has passed through the filter layer may be deteriorated.

  In order to solve such a problem, it is conceivable to provide a deaeration function for removing bubbles in the relay tank. However, in the conventional relay tank, sufficient examination for such a deaeration function has not been performed, and the above-described problems have not been solved.

  Then, this invention makes it a subject to provide the water tank which was excellent in the filtration performance by providing the relay tank excellent in the deaeration performance.

In order to solve the above problems, the present invention comprises a filtration device for filtering raw water and a raw water tank for storing raw water supplied to the filtration device, and the raw water is supplied from the raw water tank to the filtration device by the action of gravity. the a further comprising a water treatment facility relay tank for relaying the raw water between the raw water tank the filtration device, the filtration device comprises a filtration tank where the filtering is performed, the filtering tank is A filter layer on which granular filter media are deposited, and a filter tank main body in which the filter layer is accommodated, the filter tank main body having a raw water chamber above the filter layer, and filtering below the filter layer. The filtration device is obtained by the raw water flowing into the raw water chamber becoming a downward flow by the action of gravity and passing through the filter layer, and the raw water is filtered by the filter layer. A gravity-type filtration device in which filtered water is accommodated in the filtered water chamber. Has a backwash pipe for draining water from the raw water chamber, and when the water in the raw water chamber is discharged through the backwash pipe, the filtered water is transferred to the raw water chamber through the filter layer. The relay tank has a tank body for relaying the raw water, and the raw water inlet into which the raw water flows into the tank body of the relay tank And a raw water discharge port through which the raw water is discharged toward the filtration device, and an exhaust port through which the bubbles are discharged when bubbles are mixed into the raw water, and the tank body of the relay tank has And a water passage material having a plurality of water passage holes through which the raw water passes. In the tank body, when bubbles are mixed into the raw water, the air bubbles are captured by the water passage material and discharged together with the raw water. Provided is a water treatment facility in which bubbles are prevented from being discharged from an outlet.

  According to the present invention, since air bubbles in the raw water can be trapped by the water flow material provided in the relay tank, the relay tank can exhibit excellent degassing performance and provide water treatment equipment with excellent filtration performance. Can do.

Schematic showing the apparatus structure of the water treatment facility. Schematic showing the function of the loop seal tank of one embodiment. Schematic showing the function of the loop seal tank which is not equipped with a water flow material. Schematic showing the loop seal tank of another aspect. Schematic showing the loop seal tank of another aspect. Schematic showing the loop seal tank of another aspect. Schematic showing the loop seal tank of another aspect.

  Hereinafter, an embodiment of a water treatment facility according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a water treatment facility according to an embodiment of the present invention. Hereinafter, the water treatment facility of the present invention will be described by taking as an example the case where the filtration device is a gravity filtration device as shown in the figure.

  As shown in FIG. 1, the water treatment facility 1 of the present embodiment includes a raw water tank 10 that stores raw water supplied from the outside, a filtration device 20 that filters raw water stored in the raw water tank 10, and a filtration device. It has a relay tank that relays raw water to be filtered. The relay tank in the present embodiment is a loop seal tank 30 disposed at a point where the flow of raw water in the water treatment facility 1 turns from a downward flow to an upward flow. The water treatment facility 1 of the present embodiment includes a raw water introduction pipe 40 for introducing raw water from the raw water tank 10 to the loop seal tank 30. The loop seal tank 30 is provided in the water treatment facility 1 so as to remove bubbles contained in the raw water supplied from the raw water tank 10 and supply the raw water after the removal of the bubbles to the filtration device 20. . The water treatment facility 1 of the present embodiment filters the vent pipe 50 for discharging the bubbles removed from the raw water in the loop seal tank 30 from the loop seal tank 30 and the raw water after the bubbles are removed. A raw moisture pipe 60 for supplying the apparatus 20 is further provided. The filtration device 20 of the present embodiment is an automatic siphon filter type filtration device in which reverse cleaning is automatically performed when the filtration performance deteriorates. And the water treatment equipment 1 of this embodiment is provided with the waste_water | drain tank 70 which stores temporarily, before discharging | emitting the washing waste_water | drain in this reverse washing out of a system.

  The filtration device 20 has a tank body 21 (hereinafter also referred to as “filter tank body 21”) for storing raw water to be filtered and filtered filtered water, and filters the raw water into the filter tank body 21. The filter layer 22 is provided. The filtration tank body 21 includes a raw water chamber 21 a on the upper side of the filter layer 22 and a filtered water chamber 21 b on the lower side of the filter layer 22. The filtration tank main body 21 further includes a backwash water chamber 21c for storing backwash water for backwashing the filter layer 22. The backwashing chamber 21c is provided in the upper part of the raw water chamber 21a.

  The raw water tank 10 is installed so that the raw water can be supplied to the filtration device 20 by the action of gravity without using transport power such as a pump. The installation position of the raw water tank 10 in the vertical direction is higher than the loop seal tank 30, the raw water chamber 21a of the filter tank main body 21, and the backwash water chamber 21c. The raw water tank 10 of the present embodiment is disposed substantially directly above the loop seal tank 30. Therefore, the raw water introduction pipe 40 for supplying raw water to the loop seal tank 30 extends in a substantially vertical direction, and constitutes a raw water flow path between the raw water tank 10 and the loop seal tank 30. The raw water introduction pipe 40 opens upward in the vicinity of the water surface in the raw water tank 10 so that the raw water can flow into a cylindrical weir. The raw water tank 10 of this embodiment is configured to be able to supply raw water to a plurality of filtration devices, and a plurality of cylindrical weirs are formed inside by a plurality of raw water introduction pipes 40. In addition, the some raw | natural water introduction pipe | tube 40 has made the position in the perpendicular direction of the upper end distribute | arranged in the raw | natural water tank common. Accordingly, the raw water tank 10 of the present embodiment is configured to be able to supply the raw water to the plurality of raw water introduction pipes 40 substantially evenly.

  The raw water tank 10 of this embodiment is connected to the loop seal tank 30 not only by the raw water introduction pipe 40 but also by the vent pipe 50, and the raw water introduction pipe 40, the opening of the vent pipe 50, and the raw water inlet. Other than the above, it is a sealed type that does not have an opening to the outside.

  In the filtration device 20 in which the raw water is supplied from the raw water tank 10 and is filtered, the filtration tank body 21 is in the order of the filtered water chamber 21b, the raw water chamber 21a, and the backwash water chamber 21c from the bottom 3 as described above. It is a hierarchy. The filtration tank body 21 includes a side wall having a cylindrical shape (cylindrical shape, polygonal cylindrical shape, or other cylindrical shape), a bottom wall that closes a lower opening of the side wall, and a ceiling wall that closes an upper opening of the side wall. And the inner space is partitioned vertically by the filter layer 22 near the bottom wall. The raw water chamber 21a and the filtered water chamber 21b provided below the raw water chamber 21a are partitioned by a filter layer 22 so that water can pass therethrough. On the other hand, the raw water chamber 21a and the backwash water chamber 21c provided thereabove are partitioned by a non-permeable partition wall.

  The filter layer 22 in this embodiment is formed of a granular filter medium 22a. Examples of the granular filter medium 22a include water-based reference filter sand. More specifically, examples of the granular filter medium 22a include anthracite, manganese sand, and activated carbon. The filter layer 22 further includes a support plate 22b and a plurality of water passage members 22c. The support plate 22b is a plate-like body that supports the filter medium 22a, and is disposed on the lower side of the filter medium 22a so that the plate surface is substantially horizontal. The plurality of water passage members 22c have a smaller area than the support plate 22b and are disposed on the support plate 22b. The support plate 22b has a plurality of holes penetrating vertically. The water passage member 22c is disposed so as to cover the hole of the support plate 22b from above. The support plate 22b has a hole diameter larger than that of the filter medium. The hole is covered with a water passage member 22c having a water passage hole finer than the filter medium. In the filter layer 22 of this embodiment, this prevents the filter medium from falling. By having the support plate 22b in which a plurality of holes are formed and the plurality of water passage members 22c arranged in the portion in which the holes are formed, the filter layer 22 of the present embodiment can perform filtration and backwashing. Water can be transferred between the raw water chamber 21a and the filtered water chamber 21b. The water passage member 22c of the present embodiment is configured by a disk strainer formed in a disk shape, and is configured by a plurality of stacked (for example, 8 to 15) disk strainers.

  The filtration device 20 includes a communication pipe 23 for communicating the filtered water chamber 21b and the backwash water chamber 21c, and a filtered water discharge pipe 24 for discharging filtered water from the filtered water chamber 21b to the outside of the system. In addition.

  The communication pipe 23 is a tubular body extending along the vertical direction, and the upper end opening is disposed at the bottom of the backwash water chamber 21c and the lower end opening is disposed in the filtered water chamber 21b. The filtered water discharge pipe 24 is a pipe body that extends in the vertical direction like the communication pipe 23. The filtered water discharge pipe 24 has a lower end opening disposed in the filtered water chamber 21b. The filtered water discharge pipe 24 extends upward from the opening position of the communication pipe 23. The filtered water discharge pipe 24 has a branch pipe 24 a that branches toward the side wall in the vicinity of the ceiling wall of the filtration tank body 21. The branch pipe 24 a is configured to pass through the side wall and to discharge filtered water to the outside of the filtration tank main body 21.

  In the filtration device 20 in the present embodiment, the raw water tank 10 is disposed above the branch pipe 24a. The filtration device 20 causes the head pressure of the raw water flowing into the raw water introduction pipe 40 from the raw water tank 10 to act on the raw water chamber 21a, filters the raw water in the raw water chamber 21a through the filter layer 22, and the filtration obtained by the filtration. It is comprised so that water can be stored in the filtered water chamber 21b. The water head pressure acts as a pressure that pushes up the filtered water in the filtered water chamber 21b to the water level in the filtered water discharge pipe 24. That is, the filtration device 20 according to the present embodiment pushes up the water level of the filtered water discharge pipe 24 by the head pressure of the raw water flowing into the raw water introduction pipe 40, and the filtered water pushed up through the filtered water discharge pipe 24 is sent to the branch pipe 24a. It can be discharged out of the system. Moreover, the filtration apparatus 20 in this embodiment is formed so that filtrate can be moved to the said backwash water chamber 21c through the communicating pipe 23 with the head pressure of raw | natural water. That is, the filtering device 20 is formed so that the water level of the backwashing water chamber 21c in a normal state is substantially the same as the branch pipe 24a.

  The filtration device 20 of the present embodiment extends upward from the raw water chamber 21a, passes through the ceiling wall of the filtration tank main body 21, and is higher than the branch pipe 24a and lower than the raw water tank 10. A backwash tube 25 that is U-turned downward at the position is further provided.

  The backwash tube 25 has a descending portion that descends after making a U-turn at the top portion 25t (hereinafter also referred to as “backwashing tube descending portion 25d”). The backwash pipe descending portion 25d descends outside the filtration tank main body 21, and the lower end of the backwash pipe descending portion 25d enters the water in the drainage tank 70. An upper end portion of a pipe functioning as a siphon breaker is connected to the top portion 25t of the backwash pipe 25, and the siphon breaker 26 penetrates the ceiling wall of the filtration tank body 21 and the lower end portion is a backwash chamber. It arrange | positions so that it may be located in the bottom part of 21c. During normal operation of the filtering device 20, the water level at the portion where the backwash pipe 25 is raised toward the top 25t (hereinafter also referred to as “backwash pipe raising portion 25u”) is the level of the backwash water chamber 21c. It becomes higher than the water level.

  The difference H in the water level between the backwash tube 25 and the backwash water chamber 21c is caused by the resistance of the raw water passing through the filter layer 22. Therefore, the water level of the backwash pipe 25 rises as the passage resistance of the raw water rises due to the removal target substance adhering to the filter layer 22 or the like. When the water level of the backwash pipe 25 exceeds the top and the raw water begins to descend through the backwash pipe descending part 25d, the water in the raw water chamber 21a is pumped out by the siphon effect, and the pumped raw water flows into the drain tank 70. And discharged from the drain pit 71 to the outside of the system. In this way, raw water is pumped up from the raw water chamber 21a through the backwash pipe 25, and simultaneously, the filtered water in the filtered water chamber 21b moves to the raw water chamber 21a through the filter layer 22, and the filter layer 22 is backwashed. At the same time, the water in the backwashing water chamber 21c enters the filtered water chamber 21b through the communication pipe 23 and is used to continue the backwashing. When the water level in the backwashing chamber 21c is lower than the lower end of the siphon breaker 26 and air enters the siphon breaker 26 from the lower end side, the water falling through the backwash pipe lowering portion 25d is removed from the siphon breaker 26. The air is attracted, the water in the backwash pipe ascending section 25u returns and falls into the raw water chamber 21a, and returns to the normal filtration operation. In the series of operations until returning to the normal filtration operation, the filter layer 22 is back-washed with filtered water, so that the filtration performance is restored.

  In the filtration device 20 of the present embodiment, an ejector-driven water pipe 27 is disposed along the backwash pipe descending portion 25d. The ejector-driven water pipe 27 is bifurcated at the upper end, and one of the ejector-driven water pipes 27 is connected to the rising part (back washing pipe raising part 25u) immediately before the U-turn of the back washing pipe 25 and the other is the back washing pipe 25. It is connected to the top 25t. One branch pipe of the ejector-driven water pipe 27 constitutes a backwash water guiding portion 27 a for guiding backwash water from the backwash pipe 25 to the drain tank 70. The other branch pipe of the ejector drive water pipe 27 constitutes a pressure reducing part 27b for making the inside of the backwash pipe 25 into a negative pressure. For this reason, in the filtration device 20 of the present embodiment, the water in the backwash pipe 25 reaches the point where it is connected to the backwash water guiding section 27a before dropping the backwash pipe lowering section 25d. It falls to the drain tank 70 along 27. In this way, the filtration device 20 of the present embodiment generates a negative pressure in the decompression part 27b, and the water level of the backwash tube 25 easily reaches the top part 25t. That is, the filtration device 20 of this embodiment is configured such that the expression of the siphon effect by the backwash tube 25 is assisted by the ejector drive water tube 27.

  If raw water containing bubbles is supplied to the filter layer 22 during normal filtration operation, the bubbles may enter between the filter media and increase the water flow resistance of the filter layer 22. As a result, the backwash operation occurs more frequently than necessary, leading to a decrease in the operation efficiency of the filtration device 20. Therefore, the water treatment facility 1 of the present embodiment is configured to relay the supply of raw water from the raw water tank 10 to the filtration device 20 through the loop seal tank 30 and perform deaeration in the loop seal tank 30. .

  As shown in FIG. 2, the loop seal tank 30 has a tank body 31 (hereinafter also referred to as “loop seal tank body 31”) for relaying raw water to be filtered by the filtration device 20. The loop seal tank main body 31 has a raw water inlet 31 a into which the raw water is introduced, and a raw water outlet 31 b through which the raw water is discharged toward the filtration device 20. The loop seal tank 30 is provided with an exhaust port 31c in the loop seal tank main body 31 in order to remove bubbles from the raw water.

A commutation portion is formed in the loop seal tank body 31 to turn the flow direction upward from a direction other than upward until the raw water introduced from the raw water inlet 31a is discharged from the raw water outlet 31b. The loop seal tank main body 31 is provided with a water passage material 32 having a plurality of water passage holes for passing the raw water.
The loop seal tank 30 is configured such that when bubbles are mixed into the raw water, the bubbles are captured by the water passage material 32 to remove the bubbles from the raw water, and the bubbles can be discharged through the exhaust port 31c. The water flow material 32 is provided on the upstream side of the commutation part.

  The loop seal tank main body 31 of the present embodiment includes a side wall 311 having a cylindrical shape (cylindrical or polygonal cylindrical shape or other cylindrical shape), a bottom wall 312 that closes a lower opening of the side wall, and an upper opening of the side wall. The raw water inlet 31a, the raw water discharge port 31b, and the exhaust port 31c are all open at the ceiling wall 313.

  In the loop seal tank main body 31, the raw water introduction pipe 40 is connected to the raw water inlet 31a. The loop seal tank main body 31 communicates with the raw water tank 10 through a raw water introduction pipe 40. In the loop seal tank main body 31, the raw water pipe 60 is connected to the raw water discharge port 31b. The loop seal tank main body 31 communicates with the filter tank main body 21 (raw water chamber 21a) by the raw moisture pipe 60. In the loop seal tank body 31, the vent pipe 50 is connected to the exhaust port 31c. The loop seal tank main body 31 communicates with the raw water tank 10 through a vent pipe 50.

  The loop seal tank 30 includes a guide cylinder 33 that extends downward from the raw water inlet 31a to guide the raw water into the tank, and a drain that extends cylindrically from the raw water outlet 31b to the vicinity of the bottom wall 312. And a tube 34. The loop seal tank 30 of the present embodiment is configured so that the lower end of the drain tube 34 is arranged in the vicinity of the bottom wall 312 so that the raw water introduced into the tank moves horizontally along the tank bottom and It is configured to be commutated upward at the lower end portion and flow down to the raw moisture pipe 60 through the drain tube 34. That is, the loop seal tank 30 of the present embodiment is provided with a commutation portion that turns the flow direction of the raw water upward at the lower end portion of the drain tube 34.

  In the loop seal tank 30 of the present embodiment, the water passing material 32 is provided below the guide tube 33. The water-permeable material 32 in the present embodiment can be a metal woven fabric, a knitted fabric (wire mesh), a perforated plate having a plurality of through holes formed in a plate-like body, or the like. Especially, it is preferable that the said water flow material 32 in this embodiment is the said perforated plate, and it is more preferable that it is a punching metal. The punching metal preferably has an average opening diameter of 5 mm to 20 mm, and preferably has an opening ratio of 20% to 80%. The average opening diameter is obtained by calculating an average opening area obtained by averaging the opening areas of the plurality of through holes, and calculating a diameter of a perfect circle having the same area as the average opening area. Moreover, the said opening rate is a ratio of the said opening area which occupies for the unit area of a perforated panel.

  The water flow material 32 is disposed upstream of the commutation portion in the direction in which the raw water flows. That is, the water flow material 32 is disposed upstream of the lower end of the drain tube 34 in the direction in which the raw water flows. The water flow material 32 is provided to weaken the momentum of the raw water flowing in from the guide tube 33 and to prevent bubbles contained in the raw water from reaching the bottom wall 312. Therefore, the bubbles contained in the raw water introduced into the loop seal tank main body 31 can easily float toward the ceiling wall 313 by their own buoyancy because the water flow of the raw water is weakened by the water flow material 32. In this regard, when compared with the case where the water-permeable material is not provided (FIG. 3), if the water-permeable material is not provided, the momentum of the raw water flowing in from the guide tube 33x is strong, and the bubbles pass through the tank. It will move over a wide area. For this reason, when no water-permeable material is provided, bubbles easily reach the vicinity of the bottom wall 312x and are easily mixed into the drain tube 34x. On the other hand, in the present embodiment, since air bubbles can be captured by the water-permeable material 32, the air bubbles can be quickly floated and gathered on the water surface in the tank. It can be returned to the raw water tank 10 through the pipe 50. The vent pipe 50 of this embodiment communicates with the raw water tank 10. Therefore, the gas in the loop seal tank main body is efficiently discharged from the loop seal tank main body 31 using the negative pressure generated in the raw water tank 10 when the water level of the raw water introduction pipe 40 is lowered, and is quickly accommodated in the raw water tank 10. The

  In the point which can demonstrate the above functions more reliably, when the water flow material 32 is a porous plate, the raw water flowing into the loop seal tank body from the raw water inlet 31a is made to collide with the porous plate. Is preferred. That is, the perforated plate is preferably disposed in front of the raw water inlet 31a in the direction in which the raw water flows into the loop seal tank body. When the water flow material 32 is a perforated plate, the perforated plate is preferably disposed so as to face the raw water inlet 31a, and is preferably disposed such that the plate surface faces the raw water inlet 31a. .

In the loop seal tank 30 shown in FIG. 2, only one perforated plate (water-permeable material 32) is provided, and the perforated plate is arranged to be horizontal.
The perforated plate is provided between the raw water inlet 31a and the raw water outlet 31b, but does not completely partition the inside of the loop seal tank.
Specifically, the size of the porous plate is 10% to 80% of the cross-sectional area of the loop seal tank main body 31 (the area in the horizontal cross section in FIG. 2).
Therefore, until the raw water introduced from the raw water inlet 31a reaches the raw water discharge port 31b, two water movement paths are formed as shown by arrows in FIG.
That is, the loop seal tank 30 includes a first movement path through which the raw water introduced from the raw water inlet 31a moves through the perforated plate to the raw water discharge port 31b, and the raw water does not pass through the perforated plate. And a second movement path that moves to the raw water discharge port 31b is formed.
By forming this second movement path, the water pressure is reduced on the upstream side of the perforated plate, and the bubbles easily rise.
The loop seal tank 30 is configured to be able to discharge air bubbles existing upstream of the porous plate through the exhaust port 31c in the flow direction of the raw water, and the exhaust port 31c is upstream of the porous plate. Open on the side.
That is, in the loop seal tank 30, the bubbles contained in the raw water that has not yet passed through the perforated plate are removed.

  The water-permeable material 32 is preferably arranged so as to weaken the downward flow of water in the loop seal tank. As shown in FIG. 2, the loop seal tank 30 has the raw water inlet 31a facing downward in the loop seal tank body. Therefore, in the present embodiment, the perforated plate is preferably disposed below the raw water inlet 31a. The opening direction of the inflow port is not limited to the vertically downward direction, and may be obliquely downward. The perforated plate is not limited to being horizontal, and may be disposed at an inclination. The loop seal tank 30 is not limited to such an aspect, and various changes can be made.

Modification examples relating to the loop seal tank will be described with reference to FIGS.
First, the loop seal tank 30 shown in FIG. 4 is different from the loop seal tank 30 shown in FIG. 2 in that the raw water inlet 31 a is opened in the side wall 311 of the loop seal tank body 31. That is, the loop seal tank 30 shown in FIG. 4 is different from the loop seal tank 30 shown in FIG. 2 in that the inflow direction of the raw water is a horizontal direction. On the other hand, the loop seal tank 30 shown in FIG. 4 has the loop seal tank 30 shown in FIG. 2 in that a water-permeable material 32 (perforated plate) is disposed so as to face the raw water inlet 31a. And in common. In the loop seal tank 30 shown in FIG. 4, the water passing material 32 is arranged at a position where the raw water flowing into the loop seal tank main body from the raw water inlet 31 a collides, and the momentum of the raw water is reduced by the water passing material 32. This is also common to the loop seal tank 30 shown in FIG. Further, the loop seal tank 30 shown in FIG. 4 is also configured in such a manner that the bubbles are moved by entrained by the raw water by the water passing material, and the bubbles are lifted and removed in the tank. The loop seal tank 30 shown in FIG. That is, the loop seal tank 30 shown in FIG. 4 also works effectively for suppressing the performance deterioration of the filtration device, like the loop seal tank 30 shown in FIG.

  Next, the loop seal tank 30 shown in FIG. 5 has the raw water inlet 31a opened at the side wall 311 in the same manner as the loop seal tank 30 shown in FIG. On the other hand, the loop seal tank 30 shown in FIG. 5 is different from the loop seal tank 30 shown in FIG. 4 in that the raw moisture pipe 60 is connected to the side wall 311 instead of the ceiling wall 313 of the tank body 31. The raw moisture pipe 60 of the loop seal tank 30 shown in FIG. 5 is connected to a position facing the raw water inlet 31 a and is connected to a position close to the bottom wall 312. The loop seal tank 30 shown in FIG. 5 is not provided with the drain tube 34, and the raw water discharge port 31b is opened at a position where the raw moisture pipe 60 is connected to the tank body 31. The loop seal tank 30 shown in FIG. 5 is provided with a perforated plate in front of the raw water inlet 31a in the direction in which the raw water flows from the raw water inlet 31a in the same manner as the loop seal tank 30 exemplified so far. That is, the perforated plate of the loop seal tank 30 shown in FIG. 5 is disposed so as to face the raw water inlet 31a, and is disposed at a position where the raw water flowing in from the raw water inlet 31a collides. Note that the perforated plate of the loop seal tank 30 shown in FIG. 5 is inclined so as to rise upward in the raw water inflow direction. The upper end of the porous plate does not reach the ceiling wall 313 of the tank body 31, and a gap is formed between the perforated plate and the ceiling wall 313. Therefore, the raw water flowing in from the raw water inlet 31a usually passes partly through the porous plate, but the remaining part flows along the plate surface of the porous plate and passes through the gap formed near the ceiling wall 313. Move to the other side. In the loop seal tank 30 shown in FIG. 5, the raw water moved to the opposite side of the perforated plate is discharged from the raw water discharge port 31 b opened near the bottom wall 312. In the loop seal tank 30 shown in FIG. 5, the bubbles contained in the raw water move toward the ceiling wall 313 along the plate surface of the porous plate together with the raw water, and are discharged from the exhaust port 31c opened in the ceiling wall 313. And returned to the raw water tank 10 through the vent pipe 50.

  Next, the loop seal tank 30 shown in FIG. 6 is not provided with the drain tube 34, but instead is provided with a partition wall 314 that hangs down from the ceiling wall 313 and bisects the inside of the tank. The loop seal tank 30 shown in FIG. The partition wall 314 in the loop seal tank 30 is divided to divide the tank into a raw water inflow chamber 31i provided with a raw water inlet 31a and an exhaust port 31c and a raw water outflow chamber 31e provided with a raw water outlet 31b. The lower end is located above the bottom wall 312 to form a dive weir in the tank. In the loop seal tank 30 shown in FIGS. 2 and 4, a commutation portion that turns the flow direction of the raw water upward is formed at the lower end of the drain tube 34, but the loop seal tank 30 shown in FIG. The bottom part of the raw water outflow chamber 31e is a commutation part. The loop seal tank 30 shown in FIG. 6 prevents bubbles from being mixed into the raw water supplied to the filtration device 20 in the same manner as the loop seal tank 30 shown in FIGS. 2 and 4, and reduces the performance of the filtration device. It works effectively against suppression.

  Furthermore, the loop seal tank 30 shown in FIG. 7 has a water-permeable material 32 (perforated plate) formed in a cylindrical shape thicker than the drain tube 34 so as to surround the lower end portion of the drain tube 34. Is common to the loop seal tank illustrated in FIG. The loop seal tank 30 shown in FIG. 7 is also supplied to the filtration device 20 in the same manner as the loop seal tank 30 exemplified so far by arranging a porous plate upstream of the commutation portion at the lower end portion of the drain tube 34. It is possible to prevent air bubbles from being mixed into the raw water.

  As described above, various loop seal tanks can be employed as the relay tank in the present invention. In addition, the relay tank in the present invention can adopt a loop seal tank other than the above examples, and it is a matter of course that it is not necessary to be a loop seal tank. Furthermore, the water treatment facility of the present invention does not limit the filtration device combined with such a relay tank to the automatic siphon filter type gravity filtration device as exemplified above. For example, in the above, although the raw | natural water tank 10 comprised so that raw | natural water could be supplied to a some filtration apparatus is illustrated, the water treatment equipment of this invention is not limited to such illustration. Specifically, in the water treatment facility exemplified above, the upper ends of the plurality of raw water introduction pipes 40 are opened upward above the bottom of the raw water tank 10 so as to supply raw water to the plurality of filtration devices. The upper end of the raw water introduction pipe 40 is a cylindrical weir, and the raw water that naturally flows down to the inside of the raw water introduction pipe 40 beyond the cylindrical weir can be supplied to each filtration device. The case where only one raw water introduction pipe 40 is connected to the raw water tank 10 so as to supply raw water only to one filtering device is also a range intended as the water treatment facility of the present invention. In addition, the case where three or more raw water introduction pipes 40 are connected to the raw water tank 10 to supply raw water to three or more filtration devices is also a range intended as the water treatment facility of the present invention. And when the raw | natural water tank 10 supplies raw water to several filtration apparatus, the water treatment equipment of this invention does not need to make the apparatus structure after the raw | natural water introduction pipe | tube 40 common, and may make it differ suitably. good. That is, the relay tank and the water treatment facility in the present invention are not limited to the above examples.

1 Water treatment facility 10 Raw water tank 20 Filtration device 30 Loop seal tank (relay tank)
31 Loop seal tank body (tank body)
31a Raw water inlet 31b Raw water outlet 31c Exhaust port 32 Water flow material 40 Raw water introduction pipe 50 Vent pipe 60 Raw water pipe 70 Drainage tank

Claims (8)

A filtration device for filtering raw water;
A raw water tank for storing raw water to be supplied to the filtration device, and raw water is supplied from the raw water tank to the filtration device by the action of gravity;
A water treatment facility further comprising a relay tank for relaying the raw water between the raw water tank and the filtration device,
The filtration device includes a filtration tank in which the filtration is performed,
The filter tank includes a filter layer on which granular filter media are deposited, and a filter tank body in which the filter layer is accommodated,
The filtration tank body includes a raw water chamber on the upper side of the filter layer, and a filtered water chamber on the lower side of the filter layer.
In the filtering device, the raw water that has flowed into the raw water chamber becomes a downward flow by the action of gravity and passes through the filter layer, and the filtered water obtained by filtering the raw water through the filter layer is the filtered water chamber. Gravity filtration device housed in
The filtration device has a backwash pipe for draining water from the raw water chamber, and the water in the raw water chamber is discharged through the backwash pipe, so that the filtered water moves to the raw water chamber through the filter layer. And the backwashing of the filter layer is performed,
The relay tank has a tank body for relaying the raw water,
The tank body of the relay tank has a raw water inlet into which the raw water flows, a raw water discharge port through which the raw water is discharged toward the filtration device, and the bubbles are discharged when bubbles are mixed into the raw water. And an exhaust port
And the tank body of the relay tank is provided with a water-permeable material having a plurality of water holes through which the raw water passes,
The water flow material includes a first movement path in which the flow of the raw water passing through the relay tank passes through the water flow material and moves to the raw water discharge port, and the raw water without passing through the water flow material. It is arranged in the tank body so as to form a second movement path that moves to the discharge port,
In the tank main body, when air bubbles are mixed into the raw water, the air bubbles are captured by the water-permeable material, and the water treatment facility is configured to prevent the bubbles from being discharged from the raw water discharge port together with the raw water.   The water treatment facility according to claim 1, wherein the relay tank is a loop seal tank disposed at a point where the flow of the raw water turns from a downward flow to an upward flow.   Inside the tank body of the relay tank is provided with a commutation part in which the flow direction of the raw water turns upward from a direction other than upward between the raw water inlet to the raw water outlet, The water treatment facility according to claim 2, wherein is provided upstream of the commutation section.   4. The relay tank according to claim 1, wherein the water passing material is a perforated plate, and the perforated plate is disposed at a position where the raw water flowing into the main body of the water from the raw water inlet collides. The water treatment facility as described in the paragraph.   The water treatment facility according to claim 4, wherein the relay tank has a downward direction in which the raw water inlet opens toward the tank body, and the perforated plate is disposed below the raw water inlet.   The water treatment facility according to claim 4 or 5, wherein the exhaust port is provided at a position upstream of the porous plate in the flow direction of the raw water in the tank body.   The water treatment facility according to any one of claims 4 to 6, wherein only one perforated plate is arranged in the relay tank.   The water treatment facility according to any one of claims 4 to 7, wherein the perforated plate is horizontally arranged in the relay tank.

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