Rainwater treatment system

Abstract

This rainwater treatment system 1 comprises an initial rainwater separation tank 10, a first filtration tank 20, a rainwater channel 30, an adjustment storage tank 40, a second filtration tank 50, and a water storage tank 60. The initial rainwater separation tank 10 communicates with an upper rain gutter 7 and a lower rain gutter 8 for draining rainwater accumulated on the roof of a building into a road-side gutter or a river. The first filtration tank 20 filters rainwater supplied from the initial rainwater separation tank 10 to generate filtered water. The rainwater channel 30 introduces rainwater from the initial rainwater separation tank 10 to the first filtration tank 20. The adjustment storage tank 40 stores the filtered water supplied from the first filtration tank 20. The second filtration tank 50 further filters the filtered water supplied from the first filtration tank 20 and the adjustment storage tank 40 to generate pure water. The water storage tank 60 stores pure water obtained by further filtering the filtered water.

Description

Rainwater treatment system

[0001] The present invention relates to a rainwater treatment system. More specifically, it relates to a rainwater treatment system for treating rainwater and using the rainwater, for example.

[0002] Rainwater is used for various purposes, such as watering plants, flushing toilets, washing cars, and domestic water in emergencies such as disasters. And in order to realize such "rainwater utilization", rainwater is collected, stored, and further purified.

[0003] In recent years, "rainwater utilization" has been emphasized from the aspect of disaster prevention. For example, by storing rainwater in a storage tank during heavy rain and gently discharging the stored rainwater on sunny days, it is intended to maintain the drainage function in urban areas and prevent floods on roads.

[0004] Conventionally, various technologies for realizing rainwater utilization have been proposed. For example, Patent Document 1 describes a rainwater storage device that can suitably cope not only with initial rainwater but also with heavy rain without increasing in size or complexity.

[0005] Japanese Unexamined Patent Application Publication No. 2021-99013

[0006] However, the control unit provided in the rainwater storage device described in Patent Document 1 requires an external power source, and there is a problem that the device does not operate when a power failure occurs due to a disaster such as an earthquake.

[0007] Further, the rainwater storage device described in Patent Document 1 allows a part of the collected rainwater to overflow through an overflow pipe and be sent to a sewer outlet for discharge. However, rainwater is a precious resource that can be used for various purposes, and it has been desired to process and utilize rainwater efficiently while saving waste as much as possible.

[0008] The present invention has been devised in view of the above points, and an object thereof is to provide a rainwater treatment system that does not require external power and can efficiently treat rainwater.

[0009] To achieve the above objectives, the rainwater treatment system of the present invention comprises: a first filtration tank having a first filter capable of filtering introduced rainwater to produce filtered water; an adjustment storage tank communicating with the first filtration tank and capable of storing the filtered water produced by the first filtration tank; and a storage tank communicating with the first filtration tank and the adjustment storage tank, capable of storing the filtered water, and whose maximum water level for storing the filtered water is located below the maximum water level that can be stored in the adjustment storage tank.

[0010] Here, a first filtration tank having a first filter capable of filtering the introduced rainwater to produce filtered water can capture impurities contained in the rainwater introduced into the first filtration tank.

[0011] Furthermore, the adjustment storage tank, which is connected to the first filtration tank and capable of storing the filtered water generated by the first filtration tank, increases the storage capacity of the filtered water, allowing for efficient treatment of rainwater.

[0012] In other words, it is necessary to ensure sufficient water head pressure between the water level of the rainwater introduced into the first filtration tank and the storage tank, which limits the maximum water level of filtered water that can be stored in the storage tank (in other words, the height of the storage tank is limited). Therefore, if a regulating storage tank is not provided, when the storage tank becomes full, the first filtration tank will have no choice but to drain the rainwater without filtering it.

[0013] In contrast, when a regulating storage tank is provided, even if the main water tank is full, filtered water can be stored until the regulating storage tank is full. This makes it less likely that the first filtration tank will have to drain rainwater without filtering it (for example, even in the case of torrential rain, the amount of rainwater that needs to be drained will be reduced), and as mentioned above, rainwater can be treated efficiently.

[0014] While it is possible to increase the storage capacity of filtered water by increasing the capacity of the water tanks or the number of water tanks, considering that the height of the water tanks is limited in order to maintain hydrostatic head pressure, the installation area of ​​the rainwater treatment system will become larger.

[0015] In contrast, the "maximum water level of filtered water that can be stored in the adjustment storage tank" does not require securing a water head pressure between it and the "water level of rainwater introduced into the first filtration tank," and there are no particular restrictions (in other words, the height of the adjustment storage tank is not restricted). Therefore, the storage capacity of filtered water can be increased in the vertical direction, and the installation area of ​​the rainwater treatment system does not become excessively large.

[0016] Furthermore, by positioning the "maximum water level that can be stored in the reservoir" below (vertically downward) the "maximum water level that can be stored in the adjustment reservoir," if the water level of filtered water stored in the reservoir drops, filtered water stored in the adjustment reservoir can be supplied to the reservoir without requiring external power.

[0017] Furthermore, if the initial rainwater separation tank is provided, which includes a first water channel that communicates with a predetermined rain gutter, a second water channel that communicates with the first water channel at a first height position and into which rainwater exceeding the first height position is introduced, and a third water channel that communicates with the second water channel at a second height position and also communicates with the first filtration tank at a third height position which is above the second height position and into which rainwater exceeding the third height position is introduced into the first filtration tank, then impurities contained in the rainwater can be reduced in the stage before it is introduced into the first filtration tank.

[0018] In other words, rainwater can be stored in the "area below the first height of the first channel," the "area below the second height of the second channel," and the "area below the third height of the third channel" in the initial rainwater separation tank. Dust, dirt, sand, and other particles from the atmosphere can be precipitated and separated in these areas, thus reducing the amount of impurities contained in the rainwater, as described above.

[0019] Furthermore, if the communication height position between the first filtration tank and the water storage tank in the adjustment storage tank is below the maximum water level that can be stored in the water storage tank, the filtered water stored in the adjustment storage tank can be supplied to the water storage tank without requiring external power until the "water level of the filtered water stored in the water storage tank" reaches the "communication height position (vertical position) between the first filtration tank and the water storage tank in the adjustment storage tank".

[0020] Furthermore, if a second filtration tank is provided that has a second filter for further filtering the introduced filtered water, the two-stage filtration by the first filter and the second filter will allow for even more thorough capture of impurities contained in the rainwater.

[0021] For example, if the first filter deteriorates, impurities that could not be captured by the first filter may be captured by the second filter. Another example is using different materials for the first and second filters to efficiently capture various impurities contained in rainwater.

[0022] Furthermore, if the water storage tank is connected to the first filtration tank and the adjustment storage tank via a second filtration tank, filtered water that has undergone two stages of filtration by the first filter and the second filter can be stored in the water storage tank.

[0023] Furthermore, if the communication height position between the first and second filtration tanks in the adjustment storage tank is lower than the maximum water level that can be introduced into the second filtration tank, the filtered water stored in the adjustment storage tank can be supplied to the second filtration tank without requiring external power until the "water level of the filtered water introduced into the second filtration tank" reaches the "communication height position (vertical position) between the first and second filtration tanks in the adjustment storage tank."

[0024] Furthermore, if the maximum water level that can be stored in the adjustment storage tank is the same as the maximum water level that can be introduced into the first filtration tank, filtered water can be stored in the adjustment storage tank most efficiently.

[0025] In other words, since the water level of the filtered water stored in the adjustment storage tank is the same height (vertical height) as the water level of the rainwater introduced into the first filtration tank, by configuring the adjustment storage tank so that the maximum water level that can be stored in the adjustment storage tank is the same as the maximum water level that can be introduced into the first filtration tank, the storage capacity of the filtered water can be increased to the maximum extent in the height direction (vertical direction), and the entire capacity of the adjustment storage tank can be used without waste.

[0026] Furthermore, if a valve is provided to restrict the introduction of filtered water from the first filtration tank to the adjustment storage tank, it is possible to accommodate configurations such as storing filtered water only in the storage tank without storing it in the adjustment storage tank during periods of low rainfall.

[0027] The rainwater treatment system according to the present invention does not require external power and can efficiently treat rainwater.

[0028] This is a schematic front view showing an example of a rainwater treatment system to which the present invention is applied. This is a schematic plan view showing an example of a rainwater treatment system to which the present invention is applied. This is a schematic diagram showing an example of an initial rainwater separation tank included in a rainwater treatment system to which the present invention is applied. This is a schematic cross-sectional view showing an example of the internal structure of a first filtration tank included in a rainwater treatment system to which the present invention is applied. This is a schematic cross-sectional view taken along the line A-A shown in Figure 4. This is a schematic plan view (a) of a second filtration tank included in a rainwater treatment system to which the present invention is applied, and a schematic partial cross-sectional view (b) of a second filtration tank included in a rainwater treatment system to which the present invention is applied, with the main body cover partially omitted.

[0029] The following describes embodiments for carrying out the invention (hereinafter referred to as "embodiments") with reference to the drawings, in order to facilitate understanding of the present invention.

[0030] The rainwater treatment system 1 of the present invention, shown in Figures 1 and 2, includes an initial rainwater separation tank 10 that is in communication with an upper rain gutter 7 and a lower rain gutter 8 for draining rainwater accumulated on the roof of a building, for example, into a road gutter or river.

[0031] Furthermore, the rainwater treatment system 1 of the present invention includes a first filtration tank 20 that filters rainwater supplied from the initial rainwater separation tank 10 to produce filtered water. In addition, the rainwater treatment system 1 of the present invention includes a rainwater channel 30 that introduces rainwater into the first filtration tank 20.

[0032] Furthermore, the rainwater treatment system 1 of the present invention includes an adjustment storage tank 40 for storing filtered water supplied from the first filtration tank 20. In addition, the rainwater treatment system 1 of the present invention includes a second filtration tank 50 for further filtering the filtered water supplied from the first filtration tank 20 and the adjustment storage tank 40 to produce pure water.

[0033] Furthermore, the rainwater treatment system 1 of the present invention includes a water storage tank 60 for storing pure water obtained by further filtering the filtered water (here, "pure water" is a type of "filtered water" as it is filtered water).

[0034] Furthermore, the initial rainwater separation tank 10, the first filtration tank 20, the adjustment storage tank 40, the second filtration tank 50, and the water storage tank 60 are all located on the same ground surface 6. The first filtration tank 20 is installed on a foundation frame 24 located on the ground surface 6, and the adjustment storage tank 40 is also installed on a foundation frame 43 located on the ground surface 6.

[0035] The following describes the detailed structure of each component. Specifically, we will explain the "initial rainwater separation tank," "first filtration tank," "rainwater channel," "regulating storage tank," "second filtration tank," "storage tank," "filtration channel," and "overflow channel."

[0036] (Initial rainwater separator) The initial rainwater separator 10 has a first vertical channel 11. The first vertical channel 11 extends in the vertical direction, the upper end of the first vertical channel 11 is connected in communication with the upper rain gutter 7, and the lower end of the first vertical channel 11 is connected in communication with the lower rain gutter 8.

[0037] Furthermore, the upper rain gutter 7 is connected to the roof of a building, and the lower rain gutter 8 is connected to the side ditch of a road. In addition, a first vertical waterway valve 14 for controlling the amount of drainage is installed at the bottom of the first vertical waterway 11.

[0038] As a result, rainwater that accumulates on the roof of a building flows into the upper downspout 7, and if the first vertical drain valve 14 is closed, the rainwater will accumulate in the first vertical drain 11. On the other hand, if the first vertical drain valve 14 is open, the rainwater will be drained from the lower downspout 8 into a roadside ditch or the like.

[0039] Furthermore, the initial rainwater separation tank 10 has a second vertical channel 12. The second vertical channel 12 is positioned closer to the first filtration tank 20 than the first vertical channel 11 and extends vertically. Moreover, the upper vertical portion of the second vertical channel 12 is connected to the upper vertical portion of the first vertical channel 11 in a state of communication.

[0040] Furthermore, the initial rainwater separation tank 10 has a third vertical channel 13. The third vertical channel 13 is located closer to the first filtration tank 20 than the second vertical channel 12 and extends vertically. The lower vertical portion of the third vertical channel 13 is in communication with the lower vertical portion of the second vertical channel 12, and the upper vertical portion of the third vertical channel 13 is connected in communication with the rainwater channel 30.

[0041] Furthermore, as shown in Figure 3, which partially omits the outer wall of the third vertical channel 13, a debris removal screen 15 is installed inside the third vertical channel 13. When rainwater passes through the debris removal screen 15, large debris such as leaves contained in the rainwater is removed from the rainwater.

[0042] Furthermore, a backflow prevention valve 16 is provided at the connection point (horizontal portion) between the third vertical drainage channel 13 and the rainwater channel 30 to prevent "backflow" of rainwater from flowing from the rainwater channel 30 into the third vertical drainage channel 13. The arrows in Figure 3 indicate the direction of rainwater flow.

[0043] Furthermore, openings are formed at the upper and lower ends of the third vertical waterway 13, connecting the inside and the outside, and maintenance covers 17 that can be opened and closed are attached to each opening.

[0044] In a configuration without a backflow prevention valve 16, opening the maintenance cover 17 at the lower end of the third vertical water channel 13 would cause rainwater in the first filtration tank 20 to backflow and be drained (rainwater would backflow and be drained until the water level in the first filtration tank 20 fell below the position of the rainwater channel 30). Therefore, the rainwater treatment system 1 of the present invention employs a configuration in which a backflow prevention valve 16 is provided to prevent rainwater in the first filtration tank 20 from backflowing and causing excess drainage during maintenance.

[0045] Although it is possible to perform maintenance on the impurity removal screen 15 only at the opening at the lower end of the third vertical water channel 13, in the rainwater treatment system 1 of the present invention, an opening is also provided at the upper end of the third vertical water channel 13 so that maintenance can be easily performed.

[0046] (First filtration tank) The first filtration tank 20 has an inner wall made of a resin material and an outer wall made of a heat insulating material, and extends in the vertical direction. Further, the first filtration tank 20 has a cavity formed inside and is formed in a substantially cylindrical shape.

[0047] An opening for communicating the inside and the outside is formed at the upper end of the first filtration tank 20, and the lower end of the first filtration tank 20 is closed. Further, an inspection lid 25 capable of opening and closing the upper end opening is provided at the upper end of the first filtration tank 20.

[0048] The first filtration tank 20 has a first filter 21. The first filter 21 can filter rainwater to generate filtered water, and a cavity for the filtered water to pass through is formed inside along the length direction.

[0049] Openings for communicating the internal cavity and the outside are formed at the upper and lower ends of the first filter 21, and the first filter 21 is formed in a vertically long substantially cylindrical shape as a whole. Further, as shown in FIG. 4, the first filter 21 is disposed inside the first filtration tank 20 in a state of extending in the vertical direction.

[0050] The first filter 21 has a filter cloth made of a non-woven fabric or a woven fabric, and is configured, for example, in a two-layer structure including an inner layer and an outer layer. Further, "the size of the mesh of the inner layer filter cloth" and "the size of the mesh of the outer layer filter cloth" are different from each other. As a result, fine gaps are formed on the surface of the first filter 21, and impurities of various sizes can be captured while suppressing clogging.

[0051] Here, the first filter 21 does not necessarily have to be composed of a two-layer structure with fine gaps formed therein, and may be composed of a known filter material. However, as in this embodiment, it is preferable that a large number of fine gaps are formed on the surface of the first filter 21, as this ensures a filtration area, disperses the differential pressure of the hydrostatic pressure, and prevents clogging by captured impurities.

[0052] Furthermore, the first filtration tank 20 has an internal piping 22 that is roughly T-shaped. Here, the connecting end 22A of the internal piping 22 is connected so as to be able to communicate with the lower end of the first filter 21.

[0053] Specifically, the connecting end 22A has an opening that connects the inside and outside of the internal piping 22, and a portion of the internal piping 22 extends in the direction in which the first filter 21 extends. Furthermore, the connecting end 22A of the internal piping 22 is detachably connected to the lower end of the first filter 21 by the first filter insertion portion 26.

[0054] Furthermore, the end of the internal piping 22 opposite to the connecting end 22A is attached to the bottom of the first filtration tank 20.

[0055] Furthermore, the end of the branched portion of the internal piping 22 is the "external communication end 22B," which protrudes outside the first filtration tank 20 and communicates with the outside of the first filtration tank 20. In other words, the external communication end 22B has an opening that connects the inside and outside of the internal piping 22.

[0056] Furthermore, the external communication end 22B of the internal piping 22 of the first filtration tank 20 is the point where the first filtration tank 20 communicates with the adjustment storage tank 40.

[0057] Furthermore, the upper end of the first filter 21 is detachably connected to an inspection cover 25 provided at the upper end of the first filtration tank 20. This allows workers to open the inspection cover 25 during maintenance to check the internal condition and replace the first filter 21.

[0058] Furthermore, by supplying filtered water through the opening at the upper end of the first filter 21 with the inspection cover 25 open, impurities adhering to the first filter 21 can be washed away by backwashing.

[0059] Furthermore, a drain tap 23 is provided on the side near the bottom of the first filtration tank 20 so that impurities accumulated at the bottom of the first filtration tank 20 can be discharged together with rainwater.

[0060] (Rainwater channel) The rainwater treatment system 1 of the present invention is equipped with a rainwater channel 30, one end of which is closed. On the side surface near the closed end of the rainwater channel 30, an ejection hole 31 is formed that connects the inside and outside of the rainwater channel 30.

[0061] Furthermore, the rainwater channel 30 protrudes into the cavity inside the first filtration tank 20 and is connected to the side of the first filtration tank 20 in a continuous manner.

[0062] Furthermore, as shown in Figure 5, one end of the rainwater channel 30 is closed in the radial direction of the first filter tank 20, and the ejection hole 31 is open in a direction substantially perpendicular to the radial direction of the first filter tank 20.

[0063] Furthermore, as shown in Figure 4, the rainwater channel 30 is located vertically below the connection point between the internal piping 22 and the first filter 21 (i.e., the first filter insertion point 26). Moreover, the connection point between the internal piping 22 and the first filter 21 is located vertically below the approximate center of the first filtration tank 20, and as a result, the rainwater channel 30 is located vertically below the approximate center of the first filtration tank 20.

[0064] As a result, rainwater accumulates in the first filtration tank 20 from the bottom of the first filtration tank 20 up to the connection point between the internal piping 22 and the first filter 21 (i.e., the location of the first filter insertion part 26), and consequently, the rainwater channel 30 is located below the surface of the rainwater.

[0065] Then, rainwater is ejected from the ejection holes 31 of the rainwater channel 30 located below the water surface toward the curved inner wall of the first filtration tank 20, generating a swirling water flow. This swirling water flow then causes centrifugal separation, which separates impurities from the rainwater.

[0066] Furthermore, since the upper vertical portion of the third vertical channel 13 is connected to the rainwater channel 30, which is located vertically below the approximate center of the first filtration tank 20, the third vertical channel 13 is also located vertically below the approximate center of the first filtration tank 20.

[0067] As a result, the third vertical channel 13 is located at a relatively low position, and cleaning the debris removal screen 15 inside the third vertical channel 13 does not require working at heights, thereby improving the safety and work efficiency of maintenance.

[0068] Furthermore, when rainwater is introduced into the first filtration tank 20 from the rainwater channel 30, and the water level of the rainwater in the first filtration tank 20 exceeds the connection point between the internal piping 22 and the first filter 21 (i.e., the position of the first filter insertion part 26), the rainwater is filtered through the first filter 21, becomes filtered water, flows into the internal piping 22, and flows out of the first filtration tank 20 from the external communication end 22B by gravity. The arrows in Figures 4 and 5 indicate the direction of flow of rainwater and filtered water.

[0069] Furthermore, since the rainwater channel 30 is located "below the water surface of the rainwater," there is no "difference in elevation between the minimum water level (the location of the connection point between the internal piping 22 and the first filter 21) and the rainwater inlet position" that would occur if the rainwater channel 30 were located above the water surface. As a result, impurities accumulated at the bottom of the first filtration tank 20 are not stirred up, and clogging of the first filter 21 due to stirred-up impurities is less likely to occur.

[0070] Furthermore, since the rainwater channel 30 is located "vertically below the connection point between the internal piping 22 and the first filter 21," it is easier to safely perform periodic maintenance on the rainwater channel 30 than if it were located vertically above (for example, near the upper end of the first filtration tank 20).

[0071] (Adjustment Storage Tank) The adjustment storage tank 40 is in communication with the first filtration tank 20. The upper end position of the adjustment storage tank 40 in the vertical direction (here, "upper end position" means "the highest water level of filtered water that can be stored in the adjustment storage tank 40") is approximately the same as the upper end position of the first filtration tank 20 (here, "upper end position" means "the highest water level of rainwater that can be introduced into the first filtration tank 20").

[0072] Furthermore, the volume of the adjustment storage tank 40 is larger than the volume of the first filtration tank 20. In addition, the adjustment storage tank 40 is provided with a filtered water inlet / outlet 41, through which filtered water is introduced into the adjustment storage tank 40 and discharged from the adjustment storage tank 40.

[0073] Furthermore, the filtered water outlet 41 of the adjustment storage tank 40 is the "location in communication with the first filtration tank 20 and the second filtration tank 50" in the adjustment storage tank 40. Note that the filtered water outlet 41 is located vertically below the upper end position line (indicated by reference numeral 58 in Figure 1, which is the same as the "upper end position of the water storage tank 60") which will be described later as the "upper end position of the second filtration tank 50".

[0074] Furthermore, a drain tap 42 is provided on the side near the bottom of the adjustment storage tank 40 to allow the filtered water remaining at the bottom to be discharged.

[0075] (Second Filtration Tank) As shown in Figure 6, the second filtration tank 50 extends vertically, and the cross-sectional shape of the second filtration tank 50 in a direction approximately perpendicular to the direction of extension is approximately circular. An opening is formed at the upper end of the second filtration tank 50 for filtered water to be introduced into the interior and pure water to be discharged from the interior, and the lower end of the second filtration tank 50 is closed.

[0076] Furthermore, the upper end position of the second filtration tank 50 (where "upper end position" means "the highest water level of filtered water that can be introduced into the second filtration tank 50") is located vertically below the upper end position of the first filtration tank 20 and the upper end position of the adjustment storage tank 40.

[0077] Furthermore, the second filtration tank 50 has a second filter 51. The second filter 51 is capable of further filtering the filtered water to produce pure water, and is formed in a substantially cylindrical shape with a cavity 53 inside.

[0078] Furthermore, the second filter 51 is positioned inside the second filtration tank 50, extending in the direction in which the second filtration tank 50 extends. In addition, a gap 52 is formed between the inner wall of the second filtration tank 50 and the second filter 51.

[0079] Furthermore, the second filter 51 is filled with ion exchange resin, which can adsorb salt components such as calcium, sodium, and chloride, as well as metal ions, contained in the filtered water sent from the first filtration tank 20 and the adjustment storage tank 40. As a result, the second filter 51 can remove impurities that cannot be removed by the first filter 21, and produce highly pure water.

[0080] Furthermore, a filtered water inlet 54 is formed at the upper end of the second filter tank 50, opening in a direction substantially perpendicular to the direction in which the second filter tank 50 extends. In addition, the filtered water inlet 54 is in communication with the gap 52.

[0081] Furthermore, on the side opposite the filtered water inlet 54 at the upper end of the second filtration tank 50, a pure water outlet 55 is formed, which opens in a direction substantially perpendicular to the direction in which the second filtration tank 50 extends. Moreover, the pure water outlet 55 communicates with the cavity 53 inside the second filter 51. On the other hand, the filtered water inlet 54 and the pure water outlet 55 are not directly connected to each other.

[0082] Furthermore, the upper end of the second filtration tank 50 is fitted with a drain plug 56 on the filtered water inlet side and a drain plug 57 on the pure water outlet side, which are plugs for releasing air.

[0083] As a result, the filtered water introduced into the second filtration tank 50 from the filtered water inlet 54 flows into the gap 52, then passes through the second filter 51 to be filtered, and as pure water flows into the cavity 53 inside the second filter 51.

[0084] Here, the pure water does not flow back into the gap 52 from the cavity 53 inside the second filter 51 by passing through the second filter 51 again. Instead, it accumulates in the cavity 53 of the second filter 51, causing the water level of the pure water in the cavity 53 to rise.

[0085] Then, when the water level of the pure water in the cavity 53 reaches the upper end of the second filtration tank 50, the pure water flows out of the second filtration tank 50 through the pure water outlet 55. The arrows in Figure 6(a) indicate the direction of the flow of filtered water and pure water.

[0086] (Water Storage Tank) The water storage tank 60 is connected to the first filtration tank 20 and the adjustment storage tank 40 via the second filtration tank 50. The upper end of the water storage tank 60 (here, "upper end" means "the highest level of pure water that can be stored in the water storage tank 60") is located vertically below the upper end of the first filtration tank 20 and the upper end of the adjustment storage tank 40.

[0087] Furthermore, the upper end position of the water storage tank 60 in the vertical direction is approximately the same as the upper end position of the second filtration tank 50.

[0088] Furthermore, the upper end of the water storage tank 60 and the upper end of the second filtration tank 50 are in communication with each other. Here, the water storage tank 60 is in communication with two second filtration tanks 50 that are arranged in parallel with the water storage tank 60.

[0089] Furthermore, a roughly T-shaped intake channel 61 is connected to the side of the water storage tank 60 near its bottom, while communicating with the inside of the water storage tank 60. In addition, an intake faucet 62 is provided at the end of the intake channel 61, and pure water can be drawn from the water storage tank 60 using the intake faucet 62.

[0090] (Filtration channel) The first filtration tank 20, the adjustment storage tank 40, the second filtration tank 50, and the water storage tank 60 are all connected to each other via a filtration channel 2 through which filtered water can pass.

[0091] The filtration channel 2 includes a "first horizontal section 2A", a "first branch section 2B", a "second horizontal section 2C", a "vertical section 2D", a "third horizontal section 2E", a "fourth horizontal section 2F", a "drainage vertical section 2G", a "second branch section 2H", a "fifth horizontal section 2I", a "sixth horizontal section 2J", and a "drainage faucet 2K".

[0092] One end of the first horizontal section 2A is connected to the external communication end 22B of the internal piping 22 of the first filtration tank 20. The other end of the first horizontal section 2A is connected to the first branch section 2B.

[0093] Furthermore, the first branching section 2B branches in three directions, connecting to the "first horizontal section 2A" which is in communication with the first filtration tank 20, the "second horizontal section 2C" which is directed toward the adjustment storage tank 40, and the "fourth horizontal section 2F" which is directed toward the second filtration tank 50.

[0094] Furthermore, one end of the second horizontal section 2C is connected in communication with the first branch section 2B. In addition, the other end of the second horizontal section 2C is connected in communication with the lower end of the vertical section 2D.

[0095] Furthermore, the upper end of the vertical section 2D is connected to one end of the third horizontal section 2E in a state of communication. In addition, the other end of the third horizontal section 2E is connected to the filtered water inlet / outlet 41 of the adjustment storage tank 40 in a state of communication.

[0096] Furthermore, a valve 3 for the adjustment storage tank is installed in the second horizontal section 2C, and the adjustment storage valve 3 can control the amount of filtered water introduced into the adjustment storage tank 40, or the amount of filtered water discharged from the adjustment storage tank 40 to the second filtration tank 50.

[0097] Furthermore, one end of the fourth horizontal section 2F is connected in a state of communication with the first branch section 2B. In addition, the other end of the fourth horizontal section 2F is connected in a state of communication with the approximate center (vertical center) of the drainage vertical section 2G.

[0098] Furthermore, a second filter tank valve 4 is installed in the fourth horizontal section 2F, and the amount of filtered water introduced into the second filter tank 50 can be controlled by the second filter tank valve 4.

[0099] Furthermore, the upper end of the vertical drain section 2G is connected in communication with the second branch section 2H. The second branch section 2H branches in three directions, connecting to the "vertical drain section 2G" which is connected to the first filtration tank 20 and the adjustment storage tank 40, and to a pair of "fifth horizontal sections 2I" which are directed towards each of the pair of second filtration tanks 50.

[0100] Furthermore, one end of each pair of "fifth horizontal sections 2I" is connected in communication with the second branch section 2H. In addition, the other ends of each pair of "fifth horizontal sections 2I" are connected in communication with the respective filtered water inlets 54 of each pair of "second filter tanks 50".

[0101] Furthermore, one end of each pair of "sixth horizontal sections 2J" is connected in communication with the respective pure water outlets 55 of the pair of "second filtration tanks 50". In addition, the other ends of each pair of "sixth horizontal sections 2J" are connected in communication with a pair of pure water inlets 63 formed at the upper end of the water storage tank 60.

[0102] Furthermore, each of the pair of "sixth horizontal sections 2J" is fitted with a water storage tank valve 5, which allows the amount of pure water introduced into the water storage tank 60 to be controlled.

[0103] Furthermore, the lower end of the vertical drain section 2G is provided with a drain faucet 2K, which is an opening that can be opened and closed. Filtered water can be drained through this drain faucet 2K.

[0104] Incidentally, to prevent fine air bubbles from accumulating in the upper inner part (upper interior) of the "horizontal sections" such as the first horizontal section 2A of the filtration channel 2, which can impair the flow of filtered water, a vertical drain section 2G of the filtration channel 2 is provided. In other words, by providing the vertical drain section 2G, air bubbles are not allowed to remain in the horizontal sections of the filtration channel 2, but are instead guided through the fifth horizontal section 2I to the drain plug 56 on the filtered water inlet side of the second filtration tank 50, and the air is released from the drain plug 56 on the filtered water inlet side, thereby preventing the flow of filtered water from becoming impaired.

[0105] (Overflow channel) The overflow channel 70 is connected to the side of the first filter tank 20 near the upper end, while communicating with the cavity inside the first filter tank 20. The overflow channel 70 is a channel for draining rainwater to the outside of the first filter tank 20 when the water level of rainwater in the first filter tank 20 is close to full.

[0106] The rainwater treatment system 1 of the present invention includes a circulation channel 71 that extends horizontally, located vertically below the filtration channel 2. Furthermore, the lower parts of the first vertical channel 11, the lower parts of the second vertical channel 12, and the lower parts of the overflow channel 70 are in communication with the circulation channel 71.

[0107] As a result, rainwater flows into the circulation channel 71 through the first vertical channel 11, the second vertical channel 12, and the overflow channel 70, and is discharged through the circulation channel 71 to the lower rain gutter 8 which is connected to the lower part of the first vertical channel 11.

[0108] Furthermore, a first circulation valve 71A is installed in a waterway connecting the lower part of the second vertical waterway 12 and the circulation waterway 71, and the amount of rainwater drained from the second vertical waterway 12, the third vertical waterway 13, and the first filtration tank 20 can be controlled by the first circulation valve 71A.

[0109] Furthermore, the circulation channel 71 is connected in a manner that it communicates with the intake channel 61 of the water storage tank 60. More specifically, it is connected in a manner that it communicates with the "end of the intake channel 61" on the opposite side from the end where the intake faucet 62 is installed.

[0110] Furthermore, a second circulation valve 71B is installed in the circulation path 71, and the second circulation valve 71B prevents unfiltered rainwater from passing through the circulation path 71 and mixing with the pure water in the intake channel 61 of the water storage tank 60.

[0111] (Modification 1) The rainwater treatment system 1 of the present invention can also be configured without an initial rainwater separation tank 10. However, by including an initial rainwater separation tank 10, dust, dirt, sand, etc. from the atmosphere contained in the initial rainwater can be sufficiently separated before the rainwater is introduced into the first filtration tank 20.

[0112] (Modification 2) The rainwater treatment system 1 of the present invention can also be configured without a second filtration tank 50, but by including a second filtration tank 50, the filtered water obtained by filtering in the first filtration tank 20 can be further filtered to produce pure water.

[0113] (Modification 3) In the example shown in Figure 1, a configuration is given in which filtered water can be supplied directly from the first filtration tank 20 to the second filtration tank 50, but of course, the configuration is not limited to this. For example, the first filtration tank 20 and the adjustment storage tank 40 can be arranged in series so that the filtered water taken out from the first filtration tank 20 is always supplied to the second filtration tank 50 after passing through the adjustment storage tank 40.

[0114] The following describes the rainwater treatment process using the rainwater treatment system 1 of the present invention.

[0115] When it rains, rainwater that has accumulated on the roof of the building flows into the upper downspout 7, and from the upper downspout 7, the rainwater flows into the first vertical channel 11 of the initial rainwater separation tank 10.

[0116] Next, when the first vertical channel 11 is filled with rainwater, the rainwater overflowing from the first vertical channel 11 flows into the second vertical channel 12. Furthermore, as the inflow of rainwater into the second vertical channel 12 progresses and the water level in the second vertical channel 12 rises to the point where it connects with the third vertical channel 13, rainwater also flows into the third vertical channel 13.

[0117] After rainwater flows into the third vertical channel 13, the water level in the second vertical channel 12 and the water level in the third vertical channel 13 rise to the same level. When the water levels in the second vertical channel 12 and the third vertical channel 13 rise to the level of the rainwater channel 30, the rainwater flows through the rainwater channel 30 into the first filtration tank 20.

[0118] When the water level of rainwater in the first filtration tank 20 exceeds the position of the connection point between the internal piping 22 and the first filter 21 (i.e., the first filter insertion part 26), the rainwater is filtered through the first filter 21 and becomes filtered water. The filtered water flows into the internal piping 22 through the cavity inside the first filter 21 and flows out of the first filtration tank 20 from the external communication end 22B due to gravity.

[0119] Furthermore, when rainwater flows into the first filtration tank 20, causing the water level to rise and the hydrostatic pressure to increase, the amount of water passing through the first filter 21 (i.e., the flow rate) also increases accordingly.

[0120] Then, when the water level in the first filtration tank 20 reaches the position of the overflow channel 70, the water head pressure becomes maximum, and the rainwater is filtered across the entire surface of the first filter 21. As a result, the filtration area increases and the resistance of the first filter 21 decreases, further increasing the water flow rate and maximizing the treatment capacity.

[0121] Furthermore, when the water level of rainwater in the first filtration tank 20 exceeds the position of the connection point between the internal piping 22 and the first filter 21 (i.e., the first filter insertion part 26), the rainwater channel 30 is positioned below the water surface of the rainwater, and rainwater is ejected from the ejection holes 31 of the rainwater channel 30, which is positioned below the water surface, toward the curved inner wall of the first filtration tank 20, generating a swirling water flow. Due to the centrifugal force of the swirling water flow, impurities in the rainwater that are denser than the rainwater flow along the inner wall of the first filtration tank 20 and accumulate at the bottom of the first filtration tank 20.

[0122] On the other hand, impurities with the same specific gravity as or less than that of rainwater are drawn towards the center of the first filtration tank 20 along with the rainwater.

[0123] Rainwater induced towards the center of the first filtration tank 20 comes into contact with the first filter 21. As the rainwater passes through the filter cloth of the first filter 21, impurities contained in the rainwater are captured, and the filtered water that has permeated the filter cloth flows into the internal piping 22 through the cavity inside the first filter 21, and flows out of the first filtration tank 20 from the external communication end 22B.

[0124] Here, the filtered water flowing out from the external communication end 22B of the first filtration tank 20 fills the filtration channel 2, and when the water level of the filtered water reaches the filtration water outlet 41, the filtered water flows into the adjustment storage tank 40. Specifically, the filtered water flows into the adjustment storage tank 40 through the first horizontal section 2A, the first branch section 2B, the second horizontal section 2C, the vertical section 2D, and the third horizontal section 2E of the filtration channel 2.

[0125] Then, as the water level of the filtered water flowing into the adjustment storage tank 40 rises and reaches the "upper end position line" indicated by reference numeral 58 (which is the upper end position of the second filtration tank 50 and the upper end position of the water storage tank 60), the filtered water flows into the second filtration tank 50. Specifically, the filtered water flows into the second filtration tank 50 through the first horizontal section 2A, the first branch section 2B, the fourth horizontal section 2F, the drainage vertical section 2G, the second branch section 2H, and the fifth horizontal section 2I of the filtration channel 2.

[0126] The filtered water introduced into the second filtration tank 50 from the filtered water inlet 54 flows into the gap 52 inside the second filtration tank 50, passes through the second filter 51 and is further filtered, becoming pure water and flowing into the cavity 53 inside the second filter 51.

[0127] As the pure water flows into the cavity 53, it accumulates, and as the level of pure water rises and reaches the upper end of the second filtration tank 50, the pure water flows out of the second filtration tank 50 through the pure water outlet 55.

[0128] The pure water that flows out from the two second filtration tanks 50 flows into the storage tank 60 through a pair of sixth horizontal sections 2J of the filtration channel 2.

[0129] In this way, once the water storage tank 60, the sixth horizontal section 2J of the filtration channel 2, and the second filtration tank 50 are filled with pure water, filtered water will begin to flow into the adjustment storage tank 40 again, causing the water level of the filtered water flowing into the adjustment storage tank 40 to rise (the water level will rise above the "upper end position line" indicated by reference numeral 58 (which is the upper end position of the second filtration tank 50 and the upper end position of the water storage tank 60)).

[0130] Here, as filtered water flows into the adjustment storage tank 40, the water level of the filtered water in the adjustment storage tank 40 rises, but the water level of the filtered water that flows into the adjustment storage tank 40 and the water level of the rainwater that flows into the first filtration tank 20 remain at the same height.

[0131] Then, until rainwater stops flowing into the first filtration tank 20, filtered water continues to flow into the adjustment storage tank 40, causing the water level of filtered water in the adjustment storage tank 40 to continue rising.

[0132] However, if the water level of the filtered water in the adjustment storage tank 40 continues to rise (in other words, if the water level of the rainwater flowing into the first filter tank 20 continues to rise) and exceeds the height of the overflow channel 70, the water level will stop rising because the rainwater in the first filter tank 20 will be drained to the outside.

[0133] After that, the water intake tap 62 is opened to draw in pure water from the water storage tank 60.

[0134] As a result, when pure water is drawn in, the pure water in the second filtration tank 50 naturally flows into the storage tank 60. At the same time, the filtered water in the adjustment storage tank 40 and the filtered water flowing out from the first filtration tank 20 naturally flow into the second filtration tank 50. In other words, when pure water is drawn in, pure water is introduced from the second filtration tank 50 to the storage tank 60 in proportion to the amount drawn in, and at the same time, filtered water is introduced from the adjustment storage tank 40 and the first filtration tank 20 to the second filtration tank 50.

[0135] Furthermore, during periods of low rainfall, the valve 3 for the adjustment storage tank may be closed to prevent filtered water from flowing into the adjustment storage tank 40, so that all of the filtered water generated in the first filtration tank 20 is introduced only into the second filtration tank 50.

[0136] (Effects) The rainwater treatment system 1 of the present invention is equipped with an adjustment storage tank 40, which increases the storage capacity of filtered water. That is, even when the water storage tank 60, which cannot be made taller because it is necessary to secure the hydrostatic pressure between it and the first filter tank 20, is full, the first filter tank 20 does not need to discharge rainwater and can generate filtered water as long as filtered water can be stored in the adjustment storage tank 40.

[0137] Furthermore, in the rainwater treatment system 1 of the present invention, when pure water is drawn from the water storage tank 60, pure water is naturally supplied to the water storage tank 60, and rainwater can be treated efficiently without requiring external power.

[0138] Furthermore, since the adjustment storage tank 40 does not require consideration of hydrostatic head pressure and can be made larger in the height direction, it is possible to prevent the installation area of ​​the rainwater treatment system 1 from becoming excessively large.

[0139] 1. Rainwater treatment system 2. Filtration channel 2A. First horizontal section 2B. First branch section 2C. Second horizontal section 2D. Vertical section 2E. Third horizontal section 2F. Fourth horizontal section 2G. Drainage vertical section 2H. Second branch section 2I. Fifth horizontal section 2J. Sixth horizontal section 2K. Drainage tap 3. Valve for adjustment storage tank 4. Valve for second filtration tank 5. Valve for water storage tank 6. Ground surface 7. Upper downspout 8. Lower downspout 10. Initial rainwater separation tank 11. First vertical channel 12. Second vertical channel 13. Third vertical channel 14. Valve for first vertical channel 15. Debris removal screen 16. Backflow prevention valve 17. Maintenance cover 20. First filtration tank 21. First filter 22. Internal piping 22A 22B Connecting end 23 External communication end 24 Drain tap 25 Foundation frame 26 Inspection cover 26 First filter insertion part 30 Rainwater channel 31 Outlet 40 Adjustment storage tank 41 Filtered water inlet / outlet 42 Drain tap 43 Foundation frame 50 Second filtration tank 51 Second filter 52 Gap 53 Cavity 54 Filtered water inlet 55 Pure water outlet 56 Filtered water inlet side drain plug 57 Pure water outlet side drain plug 58 Upper end position line 60 Water storage tank 61 Water intake channel 62 Water intake tap 63 Pure water inlet 70 Overflow channel 71 Circulation channel 71A Valve for first circulation channel 71B Valve for second circulation channel

Claims

1. A rainwater treatment system comprising: a first filtration tank having a first filter capable of filtering introduced rainwater to produce filtered water; an adjustment storage tank communicating with the first filtration tank and capable of storing the filtered water produced by the first filtration tank; and a storage tank communicating with the first filtration tank and the adjustment storage tank, capable of storing the filtered water, and whose maximum water level for storing the filtered water is located below the maximum water level that can be stored in the adjustment storage tank.

2. The rainwater treatment system according to claim 1, comprising an initial rainwater separation tank having: a first water channel communicating with a predetermined rain gutter; a second water channel communicating with the first water channel at a first height position, into which rainwater exceeding the first height position is introduced; and a third water channel communicating with the second water channel at a second height position, and communicating with the first filtration tank at a third height position which is above the second height position, and into which rainwater exceeding the third height position is introduced to the first filtration tank.

3. The rainwater treatment system according to claim 1, wherein the communication height position between the first filtration tank and the water storage tank in the adjustment storage tank is below the maximum water level that can be stored in the water storage tank.

4. The rainwater treatment system according to claim 1, further comprising a second filtration tank having a second filter for further filtering the introduced filtered water, wherein the water storage tank is in communication with the first filtration tank and the adjustment storage tank via the second filtration tank.

5. The rainwater treatment system according to claim 4, wherein the communication height position between the first filtration tank and the second filtration tank in the adjustment storage tank is below the highest water level that can be introduced into the second filtration tank.

6. The rainwater treatment system according to claim 1, wherein the maximum water level that can be stored in the adjustment storage tank is the same as the maximum water level that can be introduced into the first filtration tank.

7. The rainwater treatment system according to claim 1, further comprising a valve that restricts the introduction of filtered water from the first filtration tank to the adjustment storage tank.

Images