JP7201278B2 - Loading type multi-stage filtration device - Google Patents

Description

TECHNICAL FIELD The present invention relates to filtration technology for storing rainwater in houses and factories for use as drinking water, and more particularly to a loading-type multi-stage filtration device in which filtration tanks are stacked in multiple stages.

It is known that a certain amount of rainfall occurs throughout the year in relatively many regions of the world, including Japan. In terms of the positioning of such rainwater in the water circulation system on the earth, it can be said that it is basically distilled water and safe water with far fewer impurities than river water, lake water, and the like.

Therefore, conventionally, such rainwater is stored and used for domestic purposes such as washing and bathing (see Patent Documents 1 to 3, etc.).
For example, the technique exemplified in Patent Document 1 discloses a method and apparatus for sterilizing and purifying rainwater.

JP-A-2000-233193 JP 2013-86034 A JP 2019-127780 A

However, it cannot be said that the current technology including the patent documents mentioned above adequately satisfies the needs of the market, and there are problems as described below.
That is, for example, Patent Document 1 and Patent Document 3 described above are intended to be used mainly for domestic use such as washing and bathing, and cannot be said to be expected to be used as drinking water. Therefore, it goes without saying that there is room for further improvement for use as drinking water.

In this respect, it is true that Patent Document 2 discloses that filtering purified water with a UF filter 16 makes the water stored in the secondary water storage tank 13 suitable for drinking. However, in Patent Document 2, although the filter 8 using the sand filtration filter is schematically depicted as being small, considering that the primary water tank 11 and the secondary water tank 13 are spaced apart from each other, the scale of the device is small. can be said to be relatively large.

Here, most of the sand filtration methods adopted in Patent Document 2 are generally of a type in which the sand filtration tank is placed horizontally on one level, and generally require a large installation area. In addition to this, the water that has fallen into the sand filter tank descends and passes through the sand filter material only within the area of the water that has fallen because the filtration resistance of the sand is extremely small. Therefore, the actual effective filtration area is extremely small, about 0.15% of the installation area, and sufficient filtration performance cannot be expected. Ensuring sufficient contact time is difficult.

The present invention has been made in view of such problems as an example, and a loading type multi-stage filtration that can efficiently improve water quality to the level of drinking use by securing a sufficient contact time with filter sand in a small space. The purpose is to provide an apparatus.

In one embodiment of the present invention, the loaded multistage filtration device comprises:
(1) A first water intake opening into which rainwater stored in a rainwater tank enters; first filtering sand for filtering the rainwater flowing in through the first water intake opening; and supporting and filtering the first filtering sand. a first filtration tank comprising a first bottom plate formed with a first communication hole through which rainwater passes;
It is connected to the lower stage of the first filtration tank so as to stack the first filtration tanks, and the rainwater that has passed through the first communication hole enters through a second water inlet opening, and the rainwater flows in through the second water inlet opening. a second filtering tank comprising: a second filtering sand for filtering rainwater, and a second bottom plate supporting the second filtering sand and formed with a second communication hole through which the filtered rainwater passes;
a clean water tank for storing at least purified rainwater filtered by the first filtration tank and the second filtration tank;
a control water tank that receives rainwater from the rainwater tank and guides it to the first water inlet opening, is connected to the clean water tank, and is capable of adjusting the water storage amounts of the rainwater tank and the clean water tank;
A loaded multi-stage filtration device comprising:
A test tank for detecting the water quality of rainwater that has passed through the second communication hole while stacking the second filtration tank so that the second filtration tank is on the upper side,
The control water tank is divided into a purified rainwater part into which the purified rainwater flows and a rainwater inflow part into which the rainwater stored in the rainwater tank flows,
Distributing the purified rainwater flowing into the control water tank into the purified rainwater part and the rainwater inflow part,
an inflow destination switching device that distributes the purified rainwater to either the purified rainwater unit or the rainwater inflow unit based on the results of inspection in a water test tank that detects the water quality of the rainwater;
a first delivery means for delivering rainwater stored in the rainwater tank to the control water tank;
a second delivery means for delivering rainwater stored in the control water tank to the first filtration tank;
a control means for controlling the first delivery means and the second delivery means;
The control means controls the first delivery means so that the rainwater stored in the rainwater tank circulates from the first filtration tank through the second filtration tank and the control water tank to the first filtration tank again. and controlling the second delivery means .

In addition, at this time, in the loading type multistage filtration device described in (1) above,
(2) It is preferable to further include sterilization means disposed between the control water tank and the first filtration tank for sterilizing the rainwater during circulation.

Further, in the loading type multi-stage filtration device described in (1) or (2) above,
(3) At least one tank disposed between the second filtration tank and the control tank, connected to the lower stage so as to stack the second filtration tanks, and receiving rainwater passing through the second communication hole. It is preferred to further have two additional filtration tanks.

Further, in the loading type multistage filtration device according to any one of (1) to (3) above,
(4) the bottom plate of the first filtration tank is formed with one or a plurality of fine discharge holes different from the first communication hole;
When an abnormality is detected in the loading type multi-stage filtration device, the rainwater stored in the first filtration tank naturally passes through the minute discharge holes without passing through the first communication hole in order to prevent the rainwater from rotting. It is preferably drained by running down.

According to the present invention, it is possible to efficiently improve the water quality of rainwater stored in a rainwater tank to the drinking level by securing a sufficient contact time with filter sand in a small space.

It is a schematic diagram which shows the loading type|mold multistage filtration apparatus in embodiment. It is a schematic diagram which shows the detailed structure of a 1st filtration tank among loading type|mold multistage filtration apparatuses. It is the structural example which each image|photographed the partition plate in which the overflow weir was formed in the 1st filtration tank in another form, and the perforated support plate in this embodiment. It is a schematic diagram which shows the detailed structure of the test tank in a loading type|mold multistage filtration apparatus. It is a schematic diagram which shows the detailed structure of the control water tank among loading type|mold multistage filtration apparatuses. FIG. 4 is a schematic diagram showing an example of a state of an inflow destination switching device (switching valve) provided in a control water tank of the loading type multistage filtration device. It is a structural example which image|photographed the loading type|mold multistage filtration apparatus in one Example. It is a flowchart which shows the rainwater filtration method in embodiment. It is a schematic diagram which shows the structure of the 1st filtration tank 20 in a modification.

Next, an embodiment for carrying out the present invention will be described.
[Loading type multi-stage filtration device 100]
A loading type multi-stage filtration device 100 according to the present embodiment will be described with reference to FIGS. 1 to 7. FIG. As shown in the figure, the loading type multi-stage filtration device 100 has a function of purifying the rainwater W stored in the rainwater tank 10 due to rainfall or the like. , a control water tank 80 and a control means CTL. As a non-limiting example, FIG. 7 shows a photograph of the actually assembled multi-stage filter device 100. As shown in FIG.

Here, the term "rainwater" in this embodiment includes not only water directly stored in the rainwater tank 10 due to rainfall, but also water that has become groundwater due to rainfall penetrating into the ground. That is, any water brought to the ground by rainfall and directly or indirectly flowed into the rainwater tank 10 is regarded as "rainwater" in this embodiment without any particular limitation.

The rainwater tank 10 has a function of storing the rainwater W described above. Such a rainwater tank 10 is preferably buried in the ground, but may be installed on the ground. As a specific shape of the rain water tank 10, for example, a known tank with a capacity of several tens to over 1,000 liters can be exemplified.

As shown in FIG. 2, the first filtration tank 20 of the present embodiment includes a first water inlet opening 21 into which rainwater W stored in the rainwater tank 10 enters, and rainwater W flowing through the first water inlet opening 21. and a first bottom plate 23 supporting the first filter sand 22 and formed with a first communication hole 23a through which the filtered rainwater W passes.

Further, as shown in the figure, the first filter tank 20 includes an outer wall 24 erected from the peripheral edge of the first bottom plate 23, a cover member 25 along the outer edge of the outer wall 24 to cover the first inlet opening 21, A partition plate 26 that partitions the inside of the first filtration tank 20 may be included. Thus, the first filtration tank 20 is partitioned into the filtration area FA and the emergency area EA by the partition plate 26 .

Also, as shown in FIG. 2(b), an overflow weir 26a is formed at the top of the partition plate 26. For example, when the first filter sand 22 is clogged, the water flows from the filtration area FA through the overflow weir 26a. The leaked rainwater W flows into the emergency area EA. As described above, in this embodiment, the presence of the overflow weir 26a prevents water from leaking from the filtration tank to an unintended area, and the water exceeding the overflow weir 26a is discharged through emergency discharge holes (such as the discharge holes 23b). safely distributed to the next stage. As a result, water leakage from each tank can be effectively prevented even when an abnormal situation occurs.

A discharge hole 23b is formed in a region of the first bottom plate 23 corresponding to the emergency region EA, and as shown in FIG. An insertion hole (not shown) into which the flow path L2 can be inserted is formed in the cover member 25, so that the rainwater W can flow into the first water inlet opening 21 with the cover member 25 in place.

The rainwater W that has flowed into the first filtration tank 20 via the flow path L2 flows into the filtration area FA described above. As described above, the filtration area FA is partitioned by the partition plate 26, and the first filter sand 22 is supported by the first support plate 27 within this partition. In this embodiment, the first filter sand 22 has a two-layer lamination structure of a first filter sand bag 22a and a first filter sand bag 22b, each of which is a filter bag having a large number of fine holes and filled with filter sand. ing.

The overflow weir 26a of the present embodiment is not limited to the V-shape shown in FIG. 2(b), but may have a concave shape as shown in FIG. may

Further, as shown in FIG. 3(b), the first support plate 27 is formed with a large number of circular holes 27a. is dripped into Thus, since the first support plate 27 of this embodiment has a large number of circular holes 27a, it is possible for the rainwater passing through the first support plate 27 to uniformly fall downward.
Furthermore, in this embodiment, an outflow adjustment member 28 is arranged below the first support plate 27 in the filtration area FA.

The outflow adjusting member 28 is formed with a reference plate 28a having a first circular hole and a second circular hole corresponding to the first circular hole, and is capable of sliding in the horizontal direction while being in contact with the reference plate 28a. and a shift arm 28c capable of horizontally moving the slide plate 28b.

Therefore, the user can align the first circular hole and the second circular hole in the vertical direction by moving the shifter 28c in the horizontal direction. Therefore, if the first circular hole and the second circular hole are positioned at the same position in the vertical direction, 100% of rainwater flows downward (toward the second filtration tank 30) through the overlapping circular holes. becomes possible.

Also, if the first circular hole and the second circular hole overlap by half in the vertical direction, the liquid flows downward through the overlapping circular hole of 50%. In other words, the user can arbitrarily adjust the flow rate of rainwater flowing downward (toward the second filter tank 30) by moving the shifter 28c in the horizontal direction.

A first communication hole 23a is formed in a region of the first bottom plate 23 corresponding to the filtration region FA, and as shown in FIG. It will flow into the tank 30 .

In the present embodiment, the first sand filter 22 is exemplified by a two-layer structure of the first filter sand bag 22a and the first filter sand bag 22b, but the first filter sand bag 22a may be composed of a single layer. , or may be in a form in which arbitrary layers of three or more layers are laminated. Thus, in this embodiment, the number and quality of filter media may be selected according to the contamination of raw water (rainwater) to be treated.
Further, in the present embodiment, sand suitable for filtration is used as the first filter sand 22 as the filter medium, but the filter medium suitable for the present embodiment is not limited to this sand material. That is, for example, various known filtration filters may be used in place of the first filtration sand 22 to form a "first filtration filter" (the same applies to other filtration tanks).

The second filter tank 30 has a function of stacking the first filter tanks 20 via a stacking stopper 23c formed on the bottom surface of the first bottom plate 23 of the first filter tank 20 .
The second to fourth filtration tanks 30 to 50 described below are substantially the same as the first filtration tank 20 except that the cover member 25 is not provided. Include or omit.

As is clear from FIGS. 1 and 2, the second filtration tank 30 of the present embodiment is connected to the lower stage of the first filtration tank 20 so as to stack the first filtration tanks 20, and the first communication hole 23a A second water intake opening 31 into which the rainwater W that has passed through the second water intake opening 31 enters; and a second bottom plate 33 in which a second communication hole 33a through which rainwater W passes is formed.

Therefore, the rainwater W that has flowed in from the first filter tank 20 is purified by removing impurities as much as it has passed through the first filter sand 22 compared to when it was stored in the rainwater tank 10 . Become.

In addition, since the 3rd filtration tank 40 and the 4th filtration tank 50 are the structures similar to the above-described 2nd filtration tank 30, the description is abbreviate|omitted. As described above, in the present embodiment, the second filtration tank 30 is arranged between the second filtration tank 30 and the control water tank 80 to be described later, and the second filtration tank 30 is connected to the lower stage so as to be stacked and passes through the second communication hole 33a. It is preferable to further have at least one additional filtration tank into which rainwater W collected is received.

Moreover, in the present embodiment, two tanks, the third filtration tank 40 and the fourth filtration tank 50, are illustrated as additional filtration tanks, but the present invention is not limited to this form. That is, the additional filtration tank of the present embodiment may be the single tank of the third filtration tank 40 described above, or may be composed of an arbitrary number of tanks of three or more.

In the present embodiment, the filter sand installed in each filter tank has a two-layer structure. It is also possible to use two layers of one filter sand bag 22a and first filter sand bag 22b, and a single layer of second filter sand bag 32a in the second filter tank 30).

The test tank 60 has the second filtration tank 30 and the like stacked so that the second filtration tank 30 and the like are on the upper side (upper side in the vertical direction), and detects the water quality of the rainwater W that has passed through the second communication hole 33a and the like. have a function.

More specifically, as shown in FIG. 4, the test tank 60 of the present embodiment includes a water quality test means 61 for detecting the water quality of the rainwater W described above, a box housing 62 housing the water quality test means 61, and a support leg 63 that is arranged in the box housing 62 and supports the water quality inspection means 61 .

In this embodiment, since the above-described two filtration tanks (the third filtration tank 40 and the fourth filtration tank 50) are further provided as additional filtration tanks, as is clear from FIG. A fourth filtration tank 50 is placed directly above.

Therefore, the rainwater W that has passed through the fourth filter sand 52 and the first communication hole 53a in the fourth filter tank 50 and has flowed into the test tank 60 (the water quality test means 61) flows from the outlet 61a of the water quality test means 61. It is delivered to the control water tank 80 via the path L3. A side wall of the box housing 62 is formed with a circular hole 62b through which the flow path L3 can pass.

On the other hand, when rainwater W overflows from the water quality inspection means 61 due to a problem occurring in the water quality inspection means 61, the overflowing rainwater W flows along the outer wall of the water quality inspection means 61 and flows from the emergency discharge port 62a. The rainwater is finally returned to the rainwater tank 10 via L4. As a result, even if water leakage should occur in the test tank 60, the leakage can be prevented from spreading around the test tank 60 because the drainage can be treated through the emergency discharge port 62a.

As a specific example of the water quality inspection means 61 for detecting the water quality of the rainwater W, various sensors capable of detecting known evaluation parameters can be applied. In this embodiment, known sensors constituting the water quality inspection means 61 described above include a sensor S1 capable of detecting the hydrogen ion concentration of the rainwater W, a sensor S2 capable of detecting the electrical conductivity of the rainwater W, and the turbidity of the rainwater W. and a sensor S4 capable of detecting the temperature of the rainwater W are applied.

The clean water tank 70 has a function of storing at least purified rainwater filtered by the first filtration tank 20 and the second filtration tank 30 . Since the additional filtration tank is provided as described above, rainwater W is filtered by the first to fourth filtration tanks 20 to 50 in this embodiment.
Here, the term "purified rainwater" refers to the rainwater whose water quality has been improved by passing through the above filtration tanks (in this example, the above four filtration tanks) out of the rainwater stored in the rainwater tank 10.

As is clear from FIG. 1, the clean water tank 70 of this embodiment communicates with the outflow hole 85 of the control water tank 80 via the inflow hole 71 formed in the side wall and the flow path CR. Therefore, the purified rainwater stored in the control water tank 80 can be delivered to the clean water tank 70 through this flow path CR. A known pump may be installed in the flow path CR or the like to send purified rainwater from the control water tank 80 to the clean water tank 70 .

Also, the clean water tank 70 is connected to the flow path L6. Purified rainwater stored in the clean water tank 70 is used as domestic water such as drinking water from the faucet K through the flow path L6. The domestic water discharged from the faucet K is drained from the sink S through the flow path L7, for example.

At this time, a water purifier PF may be further installed in the flow path L6. As such a water purifier PF, a known water purifier using a filtration system using a known filter such as fiber, activated carbon, or RO membrane can be exemplified.

The control water tank 80 receives rainwater W from the rainwater tank 10 and guides it to the first water inlet opening 21, and is also connected to the clean water tank 70 described above to adjust the amount of water stored in the rainwater tank 10 and the clean water tank 70. have.

More specifically, the control water tank 80 of this embodiment, as shown in FIG. and an inflow destination switching device 87 for switching the inflow destination of rainwater flowing into the control water tank 80 .

The control water tank 80 is divided into at least a purified rainwater portion 82 into which the above-described purified rainwater PW flows and a rainwater inflow portion 83 into which the rainwater W stored in the rainwater tank 10 flows. In the control water tank 80 of the present embodiment, in addition to the above, there are a total of three compartments, including an upstream part (the above-described filtration tanks and test tanks) or an emergency drainage part 84 into which rainwater leaking from the control water tank 80 flows. are divided into

As is clear from FIG. 5, the box housing 81 has partition walls 81a and 81b erected from the bottom surface. The rainwater inflow portion 83 and the emergency drainage portion 84 are separated by the 81b.

As shown in the figure, the rainwater inflow portion 83 is configured so that new rainwater W can be supplied from the rainwater tank 10 through the flow path L1. In addition, the rainwater inflow portion 83 is provided with a second delivery means P2 such as a known pump, and the rainwater stored in the rainwater inflow portion 83 through the flow path L2 connected to the second delivery means P2. W can be delivered to the above-described filtration tank (first filtration tank 20).

In addition, an outlet through which rainwater can flow is formed at the bottom of the emergency drainage part 84, and the leaked rainwater flows back to the rainwater tank 10 through the flow path L5 connected to the outlet as described above. configured to be

Water level sensors H1 to H3 are installed in the purified rainwater section 82 and the rainwater inflow section 83 of the control water tank 80, respectively. This makes it possible to control the inflow destination switching device 87 based on the water level values of the water level sensors H1 to H3.

The inflow destination switching device 87 has a function of dividing the purified rainwater flowing into the control water tank 80 into the purified rainwater section 82 and the rainwater inflow section 83 . More specifically, as shown in FIG. 5, the inflow destination switching device 87 of the present embodiment is composed of a known switching valve capable of switching the outflow direction, and is arranged on the partition wall 81a. there is

As a result, the rainwater flowing into the control water tank 80 from the above-described upstream portion (the first filtration tank 20, the second filtration tank 30, etc.) through the flow path L3 can be easily sent to the purified rainwater portion 82 and the rainwater inflow portion 83. It is possible to distribute.

Note that the inflow destination switching device 87 (switching valve) in the present embodiment switches the purified rainwater between the purified rainwater section 82 and the rainwater inflow section 83 based on the inspection result in the water quality test tank 60 for detecting the water quality of the rainwater. It is preferable to distribute to either. That is, depending on the initial water quality of the rainwater and the purification performance of the filtration tank, it is assumed that the water quality will not be sufficiently improved only by making one round.

Therefore, as shown in FIG. 6(a), if it is determined that the water quality has reached a predetermined standard (for example, the above-described standard for use as domestic water) as a result of the water test by the test tank 60, the control means CTL, which will be described later, Under control, the inflow destination switching device 87 is set to the purified rain water section 82 side.

On the other hand, as shown in FIG. 6(b), if the result of the water test by the water test tank 60 determines that the water quality does not meet the predetermined standard, the inflow destination switching device 87 is controlled by the control means CTL to switch the rain water It is set on the inflow portion 83 side.

As a result, for example, if the inflow destination switching device 87 is set on the rainwater inflow portion 83 side, the filtration tank and the control water tank are connected via the flow paths L2 and L3 and the second sending means P2 (such as a pump). It is possible to circulate rainwater. In addition, the rainwater flowing from the rainwater tank 10 into the control water tank 80 can circulate through the filtration tank at least two times, thereby improving the water quality.

Therefore, it can be said that the "purified rainwater" in the present embodiment is the water that has passed through the filtration tank at least once from the rainwater W stored in the rainwater tank 10 . In other words, purified rainwater refers to water that has reached a water quality that meets the purpose of use, and rainwater that has passed through the filtration tank only once is circulated and water that has passed through the filtration tank multiple times is also called "purified rainwater." handle.

When configuring the rainwater circulation system described above, the loading type multi-stage filtration device 100 of the present embodiment includes a first delivery means P1 for delivering rainwater W stored in the rainwater tank 10 to the control water tank 80, and a control water tank. A second delivery means P2 for delivering rainwater W stored in 80 to an upstream portion (first filtration tank 20), and a control means CTL for controlling the first delivery means P1 and the second delivery means P2. is preferred.

The control means CTL allows the rainwater W stored in the rainwater tank 10 to flow from the first filtration tank 20 through at least the second filtration tank 30 and the control water tank 80 to the upstream portion (the first filtration tank 20 and the like) again. It is preferred to control the first delivery means P1 and the second delivery means P2 to cycle to.

Further, as shown in FIG. 1, the loading type multi-stage filtration device 100 of the present embodiment is arranged between the above-described control water tank 80 and the upstream part (first filtration tank 20, etc.), and disinfects rainwater during circulation. It is desirable to further include sterilization means 90 for processing. This makes it possible to eliminate or sterilize various germs such as bacteria in rainwater.

Specific examples of such a sterilization means 90 include a known UV irradiation device that can be attached to the flow path L2 and performs sterilization using ultraviolet rays, an electron beam irradiation device that performs sterilization using an electron beam, and the like.

Further, in the present embodiment, the UV irradiation device is arranged in the flow path L2 as the sterilization means 90, but a light irradiation device for irradiating electromagnetic waves having different wavelengths may be arranged in series with the flow path L2. Further, the control means CTL, which will be described later, may be configured to adjust the irradiation intensity of the sterilization means 90 based on the result of the water quality inspection of the rainwater by the test tank 60 .

The control means CTL is electrically connected to the test water tank 60, the control water tank 80, or the sending means, and has a function of integrally controlling the loading type multistage filtration apparatus 100 so as to realize the above functions. are doing. As such a control means CTL, a known computer having storage means such as an arithmetic unit and a memory can be exemplified.

[Rainwater filtration method using loading type multi-stage filtration device 100]
Next, referring also to FIG. 8, a rainwater filtration method using the loading type multistage filtration device 100 according to the present embodiment will be described.
First, in step 1 , the inflow destination switching device 87 is controlled to switch the inflow destination so that the water that has passed through the filter tank flows into the control water tank 80 . As a result, the rainwater is set to circulate through the circulation system including the filtration tank in the loaded multistage filtration device 100 .

Next, in step 2, each sensor is turned on so that the water level of the rain water tank 10 and the control water tank 80 can be detected. Although the water level sensor in the rainwater tank 10 is not shown, as with the water level sensors H1 to H3 of the control water tank 80, various known water level sensors including a simple float type water level gauge can be applied.

In subsequent step 3, the control means CTL determines whether or not there is enough water in the control water tank 80 to flow through the circulation system. Specifically, the control means CTL determines whether or not there is water in the rainwater inflow portion 83 of the control water tank 80 using, for example, the water level sensor H2. It should be noted that the water level (or water volume) sufficient to circulate rainwater in step 3 does not necessarily have to be close to the full state, and is set to an arbitrary water volume according to the frequency of use of the purified rainwater PW from the clean water tank 70. You may
Then, if there is not enough water in the control water tank 80 at step 3 (No at step 3), it is determined at step 4-1 whether there is water in the rainwater tank 10 or not. A predetermined amount of rainwater is stored in the rainwater tank 10 due to rainfall or water intrusion from groundwater.

Therefore, when it is determined at step 4-1 that there is no water in the rainwater tank 10 (No at step 4-1), the control means CTL outputs an image to call attention to a display (not shown) or the like. Alternatively, a warning such as a warning is issued through a voice from a speaker (not shown) (step 4-2). In such a case, the process ends as being infeasible at this time.

If it is determined in step 4-1 that there is water that can be supplied to the rainwater tank 10 (Yes in step 4-1), the rainwater before purification is pumped from the rainwater tank 10 to the control water tank 80. (step 4-3). Specifically, in step 4-3, the control means CTL sends rainwater W from the rainwater tank 10 to the rainwater inlet 83 of the control water tank 80 via the first sending means P1 and the flow path L1.
After step 4-3, the control means CTL forcibly sets the elapsed time of circulation to zero on the assumption that water was pumped into the control water tank 80 in step 4-4.
Further, after step 4-4, the process returns to step 1, and the inflow destination is set again by the inflow destination switching device 87 so that the water circulating into the control water tank 80 flows (there is no inflow destination on the control water tank 80 side). If so, keep it as is). When the rainwater W is pumped from the rainwater tank 10 to the control water tank 80 in this manner, rainwater W before purification is newly mixed into the circulation system. Control is performed to switch the inflow destination to the control water tank 80 side.

On the other hand, if there is sufficient water in the control water tank 80 in step 3 (Yes in step 3) or after going through step 4-3, the rainwater A cycle of W is performed (step 5). More specifically, as step 5, the control means CTL controls to send the water stored in the control water tank 80 to the first filtration tank 20 through the flow path L2 via the second sending means P2 (pump). I do. At this time, if the sterilization means 90 is provided on the flow path L2, the control means CTL preferably controls the sterilization means 90 to sterilize the circulating rainwater. This makes it possible to eliminate or sterilize various germs such as bacteria in rainwater.

Since there is water in the control water tank 80 through step 5, the water is constantly circulating in the above-described circulation system via the second delivery means P2.
In subsequent step 6, it is determined whether or not the water in the control water tank 80 is full. More specifically, the control means CTL performs control to detect whether or not the rainwater inflow portion 83 is full of water, for example, based on the detection result of the above-described water level sensor H1.

When it is determined in step 6 that the control water tank 80 is full of water (Yes in step 6), the control means CTL pumps water from the rain water tank 10 to the control water tank 80 via the first delivery means P1. control to stop
In subsequent step 7-2, the control means CTL performs control to initialize measurement of the circulation time by a known time measuring means (not shown) such as a timer. That is, since new water is not pumped from the rainwater tank 10 after step 7-1, the timer value is reset to the initial value for the purpose of matching the purification time.

Then, when it is determined in step 6 that the water in the control water tank 80 is not full (No in step 6) or after step 7-2, the control means CTL starts measuring the circulation time by the above-described timing means. (step 8). As a result, water circulates between the control water tank 80 and the filtration tank for a predetermined period of time, thereby improving the water quality of the rainwater W from the rainwater tank 10 . The circulation time required for purification can be appropriately set depending on the water quality such as the turbidity of the rainwater W in the area.

Then, in step 9, the water quality of the rainwater that has passed through the filter tank is detected by the above-described test tank 60, and it is determined whether or not this rainwater has cleared the desired water quality standard. As an example, in this embodiment, the following water quality standards can be exemplified.
・Hydrogen ion concentration (pH): 5.8 to 8.6
・Electrical conductivity (S/m): 1 to 30
・Turbidity (kaolin standard): 1.0 degrees or less ・Temperature (°C): 5 to 40
Note that the above is just an example, and for example, the water quality standards based on the Waterworks Act may be applied.

If it is determined in step 9 that the circulating rainwater has cleared the desired water quality standard (Yes in step 9), it is determined in step 10 whether the circulation time has reached a specified time. On the other hand, if it is determined in step 9 that the rainwater has not yet cleared the desired water quality standard (No in step 9), the process returns to step 2 and the above processes are continued again.

In the subsequent step 10, it is determined whether or not the time measured by the time measuring means (time during which the rainwater W circulates) has reached a specified time, and when the time has reached the specified time, the process proceeds to step 11. If it is determined in step 10 that the clocked time has not reached the prescribed time (No in step 10), the process returns to step 2 and the above-described processes are continued again.

Then, in steps 9 and 10, when the water quality inspection criteria and elapsed time conditions are cleared, in other words, when the rainwater that has passed through the filtration tank has achieved the desired water quality improvement, the control means CTL switches the inflow destination. The device 87 is controlled to switch the inflow destination to the purification rainwater section 82 communicating with the clean water tank 70 (step 11). As described above, Steps 9 and 10 maintain the rainwater circulation between the control water tank 80 and the filtration tank when these conditions are not met.

By going through step 11 in this manner, the water purified by the loading type multi-stage filter device is stored in the clean water tank 70 .
Next, at step 11, it is detected whether or not the fresh water tank 70 is full. More specifically, the control means CTL can determine whether or not the water level of the clean water tank 70 has reached a predetermined level based on the detection result of a water level sensor (not shown) installed in the clean water tank 70. . As the water level sensor installed in the clean water tank 70, various known water level sensors can be applied as well as the other water level sensors described above.

If the clean water tank 70 is not full in step 11 (No in step 11), the process returns to step 2 and the above-described processes are continued again. goes to step 12.
That is, in step 13, when the clean water tank 70 is full, the purified rainwater PW is allowed to overflow to the control water tank 80 side (for example, from the purified rainwater part 82 to the rainwater inflow part 83 side).

In this step 13, for example, a weir similar to the overflow weir 26a of the partition plate 26 described above may be formed at the upper end portion of the partition wall 81a. As a result, when the clean water tank 70 and the purified rainwater section 82 of the control water tank 80 are filled with water, the purified rainwater overflows from the overflow weir at the upper end of the partition wall 81a to the rainwater inflow section 83 side. When such an overflow weir is provided, the installation of the water level sensor in the clean water tank 70 is not essential and may be omitted as appropriate. On the other hand, when a water level sensor is provided in the clean water tank 70, the control means CTL may perform control to stop pumping water from the rainwater tank 10 to the control water tank 80 when this overflow is detected. good.

Note that the overflow from the clean water tank 70 to the control water tank 80 in step 13 is not limited to the above mode. You may make it drain forcibly to.
Also, after step 13 described above, the process returns to step 2 and the above-described processes are continued again.

The rainwater filtration method described above may be carried out with continuous circulation at night when domestic water usage is relatively low. By setting such a night mode, for example, at night, the first delivery means P1 and the second delivery means P2 (each pump) in the control water tank 80 and the rain water tank 10 are always activated, and the water in the control water tank 80 is supplied. Even if the water overflows, it is possible to continue activating the sending means without stopping it to perform sterilizing filtration of the entire water in the water tank.

<Difference between the present embodiment and the conventional method>
A large horizontal sand filter tank system, which has been used for general purposes, requires a large site for its installation because it has a vast filter tank area.
On the other hand, according to the loading type multi-stage filtration apparatus of this embodiment, a continuous circulation method is adopted in which the filtration tanks are stacked on top and rainwater is circulated multiple times within the filtration tank system as necessary. It is possible to improve the water quality of rainwater stored in the rainwater tank to the drinking level with high efficiency by securing sufficient contact time with the filter sand in a small space.

In addition, in this embodiment, the rainwater in the filtration tank system can be continuously circulated a plurality of times. Since the apparent area of the sand filter material is dramatically increased due to the lamination, a significant improvement in the filtration performance of the filter material can be expected.
In addition, when maintenance such as maintenance and management of the filtration tank is taken into consideration, since a plurality of filtration tanks are stacked, the mass of one filtration tank itself is not so heavy, and the single filtration tank can be replaced sequentially as needed. It is also possible to replace only one, so maintenance can be expected to improve.

Further, in the present embodiment, for example, in the process of continuous circulation described above, by controlling the output of each delivery means (pump) by the control means CTL and adjusting the amount of rainwater discharged from the bottom of each filtration tank, It is also possible to always orient the rainwater level in the filtration area FA above each filter sand. As a result, it is possible to overcome the problem of so-called water paths (also called channeling), which has been a concern in the past, and it is possible to make meaningful use of the entire area where the filtration tank is installed. there is

The embodiment described above is one preferred mode for carrying out the present invention, and the present invention is not limited to these, and its configuration can be appropriately modified without departing from the gist of the present invention.

<Modification>
Modifications suitable for the present invention will be described below.
That is, in the above-described embodiment, as a method of adjusting the outlet flow rate of rainwater in each filtration tank, a method of opening an opening in the bottom of the filtration tank and adjusting the opening degree of this opening (first overlap adjustment in the vertical direction between the circular hole and the second circular hole).

According to this method, if the initial value is determined by adjusting the system only once at the time of installation, even if the water level rises, the flow rate of the discharged water will hydrodynamically increase and the water level will fall. Theoretically, the water level in the filtering area FA is kept constant by the action of such negative feedback, but in actual operation, due to the delay of this negative feedback, the water level fluctuates slightly up and down. end up

Therefore, in this modified example, in order to eliminate the need to adjust the water level by initial setting, a mechanism is created in which the water level is kept constant by the overflow type. In addition, the same reference numerals are given to the same configurations as those of the above-described embodiment, and the description thereof will be omitted as appropriate.
That is, as shown in FIG. 9 , the first filtration tank 20 according to the modification includes an overflow-type water level adjustment jig 29 .

The water level adjusting jig 29 is a double pipe composed of an outer pipe 29a and an inner pipe 29b, and rainwater W flows in through a gap between the outer pipe 29a and the inner pipe 29b. More specifically, the rainwater W that has passed through the first filter sand 22 provided in the filtration area FA passes through the first support plate 27 and flows into the gap between the outer tube 29a and the inner tube 29b from the bottom. Then, when the inflowing rainwater W reaches the height of the inner pipe 29b, the inflowing rainwater drops inside the inner pipe 29b.

At this time, since the bottom of the inner pipe 29b is connected to the first communication hole 23a, the rainwater W flowing through the inner pipe 29b flows downstream (the second filtration tank 30) through the first communication hole 23a. It flows out. Thus, in the filtration area FA, the water level can always be kept constant (same as the opening height of the inner pipe 29b) based on the installation height of the inner pipe 29b.
Also, as shown in the figure, the first bottom plate 23 is formed with one or a plurality of minute discharge holes 23d. The minute discharge hole 23d is set to a hole diameter (for example, a diameter of 2 mm in this example) that can discharge a flow rate that does not affect the constant water level.

In addition, in this modified example, the operation described below can also be performed.
That is, the control means CTL detects an abnormality in the operation of the loading type multistage filtration device (for example, a decrease in the flow rate due to the above-described pump failure or water leakage in the circulation system, or an electric system constituting the loading type multistage filtration device 100). When the electric power required to operate the system drops, etc.), all the operations of the above electric system are urgently stopped. In the event of an emergency shutdown of the system in the event of an abnormality, the rainwater stored in each tank is retained as is in the conventional method of configuring filtration tanks, raising concerns about the breeding of bacteria and the like.

On the other hand, according to this modification, since the first bottom plate 23 is formed with the first communication holes 23a and the minute discharge holes 23d, the balance of the amount of rainwater circulating in the filtration tank can be calculated as follows. can be shown.
"Amount of water input from flow path L2 to first filtration tank 20" = "Amount of water passing through first communication hole 23a" + "Amount of water passing through fine discharge hole 23d"

Here, when the amount of water passing through the first communication hole 23a is much larger than the amount of water passing through the minute discharge holes 23d (the amount of water passing through the first communication hole 23a >> the amount of water passing through the minute discharge holes 23d) , the water level in the filtration area FA of the first filtration tank 20 can be maintained even during the continuous operation described above. On the other hand, in the event of an emergency stop due to the above abnormality, the water can be reliably discharged to the downstream side, albeit in small amounts, through the small discharge holes 23d without passing through the first communication hole 23a.
In other words, the first bottom plate 23 of the first filtration tank 20 in this modified example has one or a plurality of small discharge holes 23d different from the first communication holes 23a. When an abnormality is detected, the rainwater that has been stored in the first filter tank 20 until then passes through the minute discharge holes 23d and is drained by gravity flow.

This prevents rainwater from remaining in each filter tank for a long period of time even during an emergency stop. In the event of such an emergency stop, rainwater will eventually disappear and only the sand filtering material will remain in the filtration area FA, making it possible to provide a kind of emergency drain function.
Although an example of the first filtration tank 20 has been described above, the fine discharge holes 23d having such a function are not limited to the first filtration tank 20. For example, the second filtration tank 30 and the third filtration tank 40 , fourth filtration tank 50 , test tank 60 , clean water tank 70 , and control water tank 80 .

INDUSTRIAL APPLICABILITY As described above, the loading type multi-stage filter device of the present invention can contribute to the provision of a space-saving filter device capable of ensuring sufficient contact time with filter sand and highly efficiently improving water quality.

REFERENCE SIGNS LIST 100 loading type multi-stage filtration device 10 rainwater tank 20 first filtration tank 30 second filtration tank 40 third filtration tank 50 fourth filtration tank 60 test tank 70 clean water tank 80 control tank 90 sterilization means CTL control means

Claims (4)

A first water inlet opening into which rainwater stored in a rainwater tank enters, first filtering sand for filtering rainwater flowing in through the first water inlet opening, and supporting the first filtering sand through which the filtered rainwater passes. a first filtration tank provided with a first bottom plate in which a first communication hole is formed;
It is connected to the lower stage of the first filtration tank so as to stack the first filtration tanks, and the rainwater that has passed through the first communication hole enters through a second water inlet opening, and the rainwater flows in through the second water inlet opening. a second filtering tank comprising: a second filtering sand for filtering rainwater, and a second bottom plate supporting the second filtering sand and formed with a second communication hole through which the filtered rainwater passes;
a clean water tank for storing at least purified rainwater filtered by the first filtration tank and the second filtration tank;
a control water tank that receives rainwater from the rainwater tank and guides it to the first water inlet opening, is connected to the clean water tank, and is capable of adjusting the water storage amounts of the rainwater tank and the clean water tank;
A loaded multi-stage filtration device comprising:
A test tank for detecting the water quality of rainwater that has passed through the second communication hole while stacking the second filtration tank so that the second filtration tank is on the upper side,
The control water tank is divided into a purified rainwater part into which the purified rainwater flows and a rainwater inflow part into which the rainwater stored in the rainwater tank flows,
Distributing the purified rainwater flowing into the control water tank into the purified rainwater part and the rainwater inflow part,
an inflow destination switching device that distributes the purified rainwater to either the purified rainwater unit or the rainwater inflow unit based on the results of inspection in a water test tank that detects the water quality of the rainwater;
a first delivery means for delivering rainwater stored in the rainwater tank to the control water tank;
a second delivery means for delivering rainwater stored in the control water tank to the first filtration tank;
a control means for controlling the first delivery means and the second delivery means;
The control means controls the first delivery means so that the rainwater stored in the rainwater tank circulates from the first filtration tank through the second filtration tank and the control water tank to the first filtration tank again. and a loading type multi-stage filtration apparatus, wherein said second delivery means is controlled . 2. The loading type multi-stage filtration apparatus according to claim 1 , further comprising sterilizing means disposed between said control water tank and said first filtration tank for sterilizing said rainwater during circulation. At least one additional filter disposed between the second filter tank and the control tank, connected to the lower stage so as to stack the second filter tanks, and receiving rainwater passing through the second communication hole. 3. A loaded multi-stage filtration apparatus according to claim 1 or 2 , further comprising a tank. The bottom plate of the first filtration tank is formed with one or a plurality of fine discharge holes different from the first communication hole,
When an abnormality is detected in the loading type multi-stage filtration device , the rainwater stored in the first filtration tank naturally passes through the minute discharge holes without passing through the first communication hole in order to prevent the rainwater from rotting. The loading type multi-stage filtration device according to any one of claims 1 to 3 , which is drained by flowing down.

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