Water treatment device

Abstract

To provide a water treatment device that suppresses an increase in pressure and flow rate and performs a stable supply of chemicals.SOLUTION: A water treatment device 1 includes: a filtration unit 2 containing a filter medium; a raw water inflow pipe 10 for flowing raw water into the filtration unit 2; a chemical supply unit 3 for adding chemicals in a path of the raw water inflow pipe 10; a purified water discharge pipe 20 for taking out treated water after filtration from the filtration unit 2; an excess drainage pipe 92 for draining unnecessary water; a bypass drainage branch 90 connected to the excess drainage pipe 92 from an upstream side of the chemical supply unit 3 in the path of the raw water inflow pipe 10; and a flow rate adjusting unit 91 for adjusting an amount of drainage flowing from the bypass drainage branch 90 to the excess drainage pipe 92, in which by discharging excess raw water whose flow rate has been adjusted by the flow rate adjusting unit 91 to outside of a system through the excess drainage pipe 92 in response to a pressure rise on a primary side, it becomes possible to supply a desired chemical solution concentration by operating the chemical supply unit 3 normally.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a water treatment apparatus for purifying water by filtration and chemical addition.

Background Art

[0002] Conventionally, for the supply of an oxidizing agent in a water treatment apparatus, a chemical supply apparatus that brings a solid oxidizing agent into contact with water has been used. For example, when purifying well water, it is possible to oxidize raw water to be purified using a chemical supply apparatus that gradually dissolves solid calcium hypochlorite.

[0003] In a system that injects chemicals with a metering pump or a chemical supply apparatus that elutes a fixed amount of chemicals regardless of the flow rate, the chemical concentration decreases when the flow rate increases.

[0004] As shown in FIG. 7, in the solid chemical supply apparatus 101, raw water flows in from the water intake 102 and the raw water is brought into contact with the water-soluble solid chemical 103. When the flow rate increases within a certain range, the water level in the chemical contact phase 104 rises, and it is possible to increase the amount of the water-soluble solid chemical 103 to be brought into contact. With this mechanism, even when the flow rate increases, the chemical elution amount increases, and it is possible to suppress a decrease in the chemical concentration (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In such a water treatment apparatus, it is necessary to adjust the addition amount of the chemical to obtain a chemical solution with a desired concentration. In particular, it is desired to obtain a chemical solution with a desired concentration with a simple configuration.

[0007] Therefore, the present invention solves the above-mentioned conventional problems. By suppressing excessive water flow and pressure from being applied to the solid chemical supply device inside the water treatment apparatus, it restricts the water pressure and water flow of the raw water in which the chemical is immersed, and aims to provide a water treatment apparatus capable of obtaining a chemical solution with a desired concentration.

Means for Solving the Problems

[0008] And, in order to achieve this object, the water treatment apparatus according to the present invention includes a filtration unit containing a filter medium, and the filtration unit Connected to a raw water inflow pipe for allowing the raw water to flow in, Provided upstream of the filtration unit in the raw water inflow pipe inside the path of the raw water inflow pipe To the raw water flowing through a chemical supply unit for adding a chemical, and a purified water discharge pipe for taking out the filtered raw water from the filtration unit Purified and an excess drain pipe for draining the above-mentioned source water. It has A part of the raw water flowing through the path of the raw water inflow pipe towards the chemical supply unit A bypass drainage branch part is provided inside the path of the raw water inflow pipe, which is connected to the excess drain pipe from the upstream side of the chemical supply unit, and a flow rate adjustment part for adjusting the drainage volume flowing from the bypass drainage branch part to the excess drain pipe is provided. The flow rate adjustment part has a valve that opens when the pressure caused by the flow of the raw water inflow pipe exceeds a predetermined value, and thus achieves the intended purpose. The filtered water into which the raw water added with the chemical flows

Effects of the Invention

Brief Description of the Drawings

[0009] Schematic diagram of the overall configuration of the water treatment apparatus according to Embodiment 1 of the present invention

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] (Embodiment 1) The water treatment device 1 according to the present embodiment uses well water or water stored in a water storage tank as raw water, and performs a filtration treatment for removing metal ions and turbidity components contained in the raw water, and an inverse washing treatment for discharging aggregates of metal ions and turbidity components accumulated in the system to the outside of the system by the filtration treatment.

[0013] FIG. 1 is a schematic diagram showing the overall configuration of the water treatment device 1 of the present embodiment and the flow of water during filtration treatment. FIG. 2 shows the piping structure of the water treatment device 1 in a perspective view.

[0014] As shown in FIGS. 1 and 2, the water treatment apparatus 1 includes a filtration unit 2 containing a filter medium and a chemical supply unit 3 for adding a chemical to raw water, and the filtration unit 2 and the chemical supply unit 3 are connected by pipes as described below. The filtration unit 2 removes metal ions and turbidity components from the raw water and purifies the raw water. It is, so to speak, the heart of the water treatment apparatus 1. The dirt accumulated in the filtration unit 2 can be kept clean by performing an operation (backwashing) to reverse the flow of the raw water to discharge the dirt and then performing an operation (rinsing) to flow the raw water in the filtration direction, and the filtration unit 2 can be repeatedly used. For this filtration unit 2, the pipe on the side for sending the raw water is defined as the raw water inflow pipe 10, the pipe for sending out the water purified by the filtration unit 2 from the filtration unit 2 is defined as the purified water discharge pipe 20, the pipe for discharging the dirt during the backwashing operation is defined as the backwash drain pipe 40, and the pipe for discarding the raw water during the rinsing process is defined as the rinse drain pipe 27. The purified water is stored in a purified water tank or the like provided outside the water treatment apparatus 1 and will be used as domestic water when needed.

[0015] For the water treatment apparatus 1, the raw water is sent by an electric pump 4 connected to the inlet side of the raw water inflow pipe 10 (the side opposite to the filtration unit 2). Instead of using the electric pump 4, a method may be adopted in which a water storage tank is provided at a high place and the raw water is sent to the water treatment apparatus 1 by the height difference between the water storage tank and the water treatment apparatus 1. Also, tap water jointly operated in a region or the like may be directly connected. In the present embodiment, in addition to wells, water storage tanks, water supply systems, etc., the water source includes devices for sending out the raw water.

[0016] The electric pump 4 is a pump driven by an electric motor that sucks up and discharges well water or water stored in a water storage tank. For example, centrifugal pumps such as volute pumps and turbine pumps, as well as vortex pumps (cascade pumps), jet pumps, axial flow pumps, mixed flow pumps, etc. can be used. Also, when the well water level is low, instead of a suction type pump, it is advisable to use a submersible pump or other underwater pump. When used in ordinary households, for shallow wells, the well depth needs to be about 1 meter to 10 meters, and for deep wells, it needs to suck up water from 10 meters to 30 meters or more. Considering the head loss of the subsequent piping and water treatment equipment, those with a lift of 20 meters or more are better, and vortex pumps and jet pumps are more preferable. The flow rate discharged by the electric pump is, for example, about 5 liters to 100 liters per minute, but for ordinary household use, those with a flow rate characteristic of about 5 liters to 50 liters per minute are more preferable.

[0017] The raw water inflow pipe 10 and the purified water discharge pipe 20 may be made of a material and structure that can withstand the water pressure of the electric pump 4. Specifically, for durability and ease of processing, for example, straight pipes and pipe joints made of vinyl chloride resin, steel pipes, or composite materials thereof can be used. Note that the nominal diameter is preferably larger so that the head loss is low. For example, those with a nominal diameter of 13 to 50 millimeters and a thickness of about 1 to 5 millimeters are preferable. When it is difficult to select a member that can withstand the maximum pressure of the electric pump 4, it is advisable to install a pressure reducing valve, a pressure regulating valve, or a relief valve between the electric pump 4 and the water treatment device 1.

[0018] The chemical supply unit 3 is provided in the path of the raw water inflow pipe 10. Specifically, as will be described later, the chemical supply unit 3 adds an oxidizing agent to the raw water, aggregates the metal ions contained in the raw water into substances hardly soluble in water, and facilitates collection in the filtration unit 2.

[0019] (Filtration unit) The filtration unit 2 is filled with a filter medium inside and purifies water by passing raw water through it. The filter medium is composed of three layers: activated carbon in the upper layer, manganese sand in the middle layer, and gravel in the lower layer. In the filtration unit 2 of this embodiment, the filtering action mainly works on the upper and middle layers. On the other hand, a gravel layer with a relatively large particle size is provided in the lowermost layer to improve the water flow and prevent the filter medium from flowing out from the lower part. With such a configuration, raw water flows into the filtration unit 2 from the inlet, and purified water is discharged from the outlet.

[0020] (Chemical supply unit) Next, the chemical supply unit 3 will be described with reference to FIGS. 2, 3, and 4.

[0021] As described above, the chemical supply unit 3 is provided to promote the aggregation of metal ions contained in the raw water by the chemical contained therein and make it easier to capture them in the filtration unit 2. As shown in FIG. 2, the chemical supply unit 3 is arranged at the uppermost part of the water treatment device 1. That is, as shown in FIG. 3, the chemical supply unit 3 is provided at the upper part of the pipe that rises upward from the raw water inlet 11 in the raw water inflow pipe 10. Also, the pipe (outflow path 34) from the outlet of the chemical supply unit 3 extends downward and is then connected to the filtration unit 2 via the branch part 13. The chemical supply unit 3 has an inflow path 31, a chemical path 32, a bypass path 33, and an outflow path 34. The inflow path 31 is connected to the raw water inflow pipe 10 and allows raw water to flow into the chemical supply unit 3. The chemical path 32 branches off from the inflow path 31 and dissolves the chemical. The bypass path 33 also branches off from the inflow path 31 and is provided to adjust the chemical solution to the required concentration. The outflow path 34 merges with the chemical path 32 and the bypass path 33, reconnects to the raw water inflow pipe 10, and sends out the raw water containing the chemical to the raw water inflow pipe 10. As shown in FIG. 4, the chemical path 32 is composed of a jet pipe 52 that rises vertically after branching, a chemical placement part 53 that contacts the chemical at the upper part of the jet pipe 52 and elutes the chemical, and a recovery part 54 that is on the outer periphery of the jet pipe 52 and is inside the housing 51.

[0022] The ejection pipe 52 is a small-diameter pipe and is erected with a chemical agent placement part 53 provided at the upper part. By making the diameter of the lower part of the ejection pipe 52 smaller and providing the chemical agent placement part 53 at the upper part of the ejection pipe 52, it is realized that raw water is brought into contact with the chemical agent at a desired flow rate. The chemical agent placement part 53 is sized to ensure the amount (number) of the chemical agent to be placed so that a chemical solution with a desired concentration can be obtained with respect to the flow rate of the raw water.

[0023] The chemical solution in which the chemical agent is dissolved flows out to the recovery part 54. In the recovery part 54, the chemical solution in which the chemical agent is dissolved accumulates at the lower part of the housing 51, and then flows out from the recovery opening 55 to the outflow path 34. Since the diameter of the ejection pipe 52 is made smaller and a distance from the inner wall surface of the housing 51 is ensured, the raw water in which the chemical agent has melted and flowed down in the housing 51 can have a liquid level that is about 1 / 2 or less with respect to the height of the housing 51. The chemical solution accumulates in the housing 51 at a desired depth, whereby the mixing ratio with the raw water in the outflow path 34 is adjusted.

[0024] And by setting the inflow amount of the raw water into the chemical agent supply part 3 within a predetermined range and making the liquid level in the chemical agent supply part 3 a desired height, the chemical agent concentration of the raw water flowing out from the chemical agent supply part 3 can be adjusted within a desired range.

[0025] Also, in order to set the inflow amount of the raw water into the chemical agent supply part 3 within a predetermined range, it is also important to ensure the air in the housing 51. Therefore, air can be taken in from the air supply valve 43 installed at the subsequent stage of the chemical agent supply part 3 and supplied to the chemical agent supply part 3 via the backwash drain pipe 40. Also, in order to make the liquid level a desired height, there is also a method of adjusting the pressure for sending the raw water during operation. When the pressure in the chemical agent supply part 3 rises, the pressure in the chemical agent supply part 3 can be adjusted within a desired range by adjusting the amount of the raw water discharged through the flow rate adjustment part 91 described later.

[0026] The chemical agent placement section 53 is provided with a solid chemical agent, that is, a water-soluble solid chemical agent 60. As the water-soluble solid chemical agent 60, tablets or granules are preferably used. This is because the surface area of the water-soluble solid chemical agent 60 can be increased and a stable solvent concentration can be maintained. If it is a tablet, it is advisable to use one with a diameter of 30 mm and a height of 10 to 20 mm. If it is granular, it is advisable to use one with a diameter of 5 mm to 15 mm. When the size of the water-soluble solid chemical agent 60 is small, adjacent chemical agents may come into contact with water simultaneously and the chemical agents may stick to each other. If they stick together, only the lower part of the chemical agent may come into contact with water and a chemical solution with a desired concentration may not be obtained. Alternatively, when the size of the water-soluble solid chemical agent 60 is small, the contact area with the water supplied from the ejection pipe 52 becomes large and a chemical solution with a desired concentration may not be obtained. Therefore, in order to supply a chemical solution with a desired concentration, the water-soluble solid chemical agent 60 with the above-mentioned size is used.

[0027] Also, as described above, the water-soluble solid chemical agent 60 functions to oxidize metal ions contained in raw water to generate aggregates that are hardly soluble in water. As the water-soluble solid chemical agent 60, various oxidizing agents can be used, but depending on the required water purification performance, high molecular coagulants such as PAC (polyaluminum chloride) and chitosan may also be used. When adding a chemical agent to raw water, the water-soluble solid chemical agent 60 is preferably easily soluble in water. However, during stoppage or backwashing, that is, when the addition of the chemical agent is interrupted, it is preferably in a solid shape and does not flow out from the chemical agent placement section 53. In the present embodiment, trichloroisocyanuric acid is used.

[0028] Since each member of the chemical supply unit 3 may come into contact with the chemical for a long time, it is advisable to select a material with low reactivity to chemicals, such as PVC (polyvinyl chloride), PMMA (polymethyl methacrylate), or PP (polypropylene). On the other hand, since the ejection pipe 52 requires strength to support the chemical placement section 53, considering the compatibility with the chemical, it is preferable to select a material for the ejection pipe 52 that is stronger than PP, such as vinyl chloride or ABS (acrylonitrile-butadiene-styrene). The outer diameter of the ejection pipe 52 should be kept at 1 / 4 or less of the inner diameter of the base 51a and the upper cover 51b. As described above, a space (recovery section 54) can be provided outside the ejection pipe 52 to temporarily store the solution after the chemical supply discharged from the placement section outlet 58, which can prevent the water level in the housing 51 from rising rapidly and reaching the chemical placement section 53. For example, when the inner diameter of the base 51a is 130 mm, a vinyl chloride pipe with an outer diameter of about 25 to 40 mm can be used.

[0029] (Pipe Configuration) In the water treatment apparatus 1 of the present embodiment, in the filtration section 2, in addition to filtering the raw water and taking out the purified water, it has a function of discharging the particulate matter (dirt, turbidity components, metal aggregates, etc.) collected in the filtration section 2 to the outside of the system by backwashing. Next, the pipe configuration in the water treatment apparatus 1 and the flow of water in the filtration process and the backwashing process will be described.

[0030] As shown in FIG. 1, the raw water inflow pipe 10 is connected from the raw water inlet 11 on the water source side to the filtration section 2 via the chemical supply unit 3 during the filtration process. A bypass drainage branch section 90 is provided upstream of the chemical supply unit 3 in the path of the raw water inflow pipe 10. Although details will be described later, a flow rate adjustment section 91 is provided on the downstream side of the bypass drainage branch section 90, which functions to adjust the amount of water flowing through the raw water inflow pipe 10. The purified water discharge pipe 20 is connected from the filtration section 2 to the purified water outlet 21 of the water treatment apparatus 1 during the filtration process.

[0031] Using FIG. 1, the flow of water during backwashing is described. During backwashing, the flow of water in the filtration section 2 is reversed. Therefore, during backwashing, in the filtration section 2, water is sent from the purified water discharge pipe 20 side to the filtration section 2, and water is discharged from the raw water inflow pipe 10 side. The water treatment apparatus 1 according to the present embodiment can perform filtration treatment and backwashing with a single water source (electric pump 4). Therefore, in order to allow raw water to flow from the purified water discharge pipe 20 side in the filtration section 2 during backwashing, a backwash water supply pipe 80 that connects the raw water inflow pipe 10 and the purified water discharge pipe 20 is provided. Here, in the raw water inflow pipe 10, a branch section 13 with a backwash drain pipe 40 that discharges the backwash drain flowing out from the filtration section 2 during backwashing is provided as the first branch section between the chemical supply section 3 and the filtration section 2. Further, the connection section of the backwash water supply pipe 80 with the raw water inflow pipe 10 is defined as a branch section 12 as the second branch section. The connection section of the backwash water supply pipe 80 and the purified water discharge pipe 20 is defined as a branch section 22 as the third branch section.

[0032] In such a piping configuration, during filtration treatment, water flows as follows.

[0033] [Flow path during filtration treatment] Raw water inlet 11 → (Raw water inflow pipe 10) → Branch section 12 → Chemical supply section 3 → Branch section 13 → Filtration section 2 → (Purified water discharge pipe 20) → Branch section 22 → Purified water outlet 21 Note that a check valve 62 is provided in the path of the purified water discharge pipe 20. The purified water taken out from the purified water outlet 21 is often connected by piping to a purified water tank provided at a high place. The check valve 62 stops the backflow of the purified water from the purified water tank provided at a high place and prevents the reverse inflow of water into the filtration section 2.

[0034] On the other hand, during backwashing, water flows as follows.

[0035] [Flow path during backwashing] Raw water inlet 11 → (Raw water inflow pipe 10) → Branch section 12 → (Backwash water supply pipe 80) → Branch section 22 → (Purified water discharge pipe 20) → Filtration section 2 → (Raw water inflow pipe 10) → Branch section 13 → (Backwash drain pipe 40) → Backwash drain port 41 In the filtration process and the backwashing process, on-off valves are provided at the branch portions 12, 13, and 22 to switch the communication direction so as to form the above water flow.

[0036] In the water treatment apparatus 1 of the present embodiment, the above switching is realized by four on-off valves (two-way valves). That is, a backwash water supply valve 81 provided in the backwash water supply pipe 80, a chemical supply valve 14 provided between the branch portion 12 and the chemical supply unit 3 in the raw water inflow pipe 10, a purified water extraction valve 23 provided between the branch portion 22 and the purified water outlet 21 in the purified water discharge pipe 20, and the opening and closing combinations of the backwash valve 42 provided in the backwash drain pipe 40 switch the water flow of the filtration process and the backwashing process.

[0037] During the filtration process, the chemical supply valve 14 and the purified water extraction valve 23 are opened, and the backwash water supply valve 81 and the backwash valve 42 are closed. That is, at the branch portion 12, the raw water inlet 11 and the chemical supply unit 3 are communicated, at the branch portion 13, the chemical supply unit 3 and the filtration unit 2 are communicated, and at the branch portion 22, the filtration unit 2 and the purified water outlet 21 are communicated.

[0038] On the other hand, during the backwashing process, the chemical supply valve 14 and the purified water extraction valve 23 are closed, and the backwash water supply valve 81 and the backwash valve 42 are opened. That is, at the branch portion 12, the raw water inlet 11 and the backwash water supply pipe 80 are communicated, at the branch portion 13, the connection side of the filtration unit 2 with the raw water inflow pipe 10 and the backwash drain port 41 are communicated, and at the branch portion 22, the connection side of the backwash water supply pipe 80 and the purified water discharge pipe 20 of the filtration unit 2 are communicated.

[0039] That is, the communication direction of the branch portion 12 is switched by the chemical supply valve 14 and the backwash water supply valve 81. Also, the water extraction port is determined by the purified water extraction valve 23 and the backwash valve 42.

[0040] Also, when performing the backwashing process, a large flow rate is required. That is, the flow rate during the filtration process is made smaller than the flow rate during the backwashing process. Therefore, a throttle portion is provided in a part of the pipe through which the water passes during the filtration process to suppress the flow rate during the filtration process. Specifically, a throttle portion 24 is provided on the downstream side of the branch portion 22 in the purified water discharge pipe 20. By combining this throttle portion 24 with the electric pump 4, the flow rate during the filtration process is set to a desired design value.

[0041] On the other hand, since there is no portion with a reduced diameter such as the throttle portion 24 in the pipe during the backwashing process, a larger flow rate than during the filtration process can be ensured, and the backwashing process can be efficiently performed. That is, the minimum diameter portions of the pipes used only during backwashing, the backwash water supply pipe 80, and the backwash drain pipe 40 are larger than the opening of the throttle portion 24.

[0042] In addition, the water treatment apparatus 1 of the present embodiment can perform a "rinsing process" for discharging foreign substances remaining in the pipe during the backwashing process. This rinsing process will be described with reference to FIG. 1. The pipe for performing the rinsing process includes a branch portion 26, a rinse drain pipe 27, and a rinse drain valve 28 in the purified water discharge pipe 20. The branch portion 26 is provided between the branch portion 22 and the purified water outlet 21 in the purified water discharge pipe 20. And the branch portion 26 branches the rinse drain pipe 27 from the purified water discharge pipe 20. The rinse drain valve 28 opens and closes the rinse drain pipe 27, and when opened, allows the water flowing through the purified water discharge pipe 20 to flow to the rinse drain port 29. During the filtration process and the backwashing process, the rinse drain valve 28 is closed.

[0043] For the rinsing process, the chemical supply valve 14 is opened, the purified water extraction valve 23 is closed, the backwash water supply valve 81 and the backwash valve 42 are closed. Further, the rinse drain valve 28 is opened. By such valve operations, during the rinsing process, water will flow as follows.

[0044] [Flow path during rinsing process] Raw water inlet 11 → (Raw water inflow pipe 10) → Branch part 12 → Chemical supply part 3 → Branch part 13 → Filtration part 2 → (Purified water discharge pipe 20) → Branch part 22 → (Throttle part 24) → Branch part 26 → Rinse drain port 29 Immediately after the backwash process is completed, foreign matter washed out by the backwash of the filtration part 2 remains in the filtration part 2 or in the pipes of the water treatment device 1. Therefore, the foreign matter can be discharged by the rinsing process.

[0045] Also, in the water treatment device 1 of the present embodiment, a direct drain pipe 70 that bypasses the throttle part 24 and a direct drain valve 71 that opens and closes the direct drain pipe 70 are provided. Since the throttle part 24 is a part where the pipe diameter is reduced, foreign matter is likely to clog. Therefore, during the backwash process for discharging foreign matter, the direct drain valve 71 should be opened and the flow should bypass the throttle part 24, which is the minimum diameter part.

[0046] Also, depending on the degree of contamination of the raw water, it may be better to drain the water directly without passing it through the filtration part 2. In such a case, the direct drain valve 71 should be opened. For example, when well water is used as the raw water, immediately after the installation of the water treatment device 1, the degree of contamination of the accumulated well water is high. If the filtration process (passing through the filtration part 2) is performed as it is, the desired purification performance cannot be obtained, and water containing foreign matter will flow out from the purified water outlet 21. Therefore, it is advisable to drain the initial raw water immediately after installation without filtration. That is, by opening the backwash water supply valve 81 and the rinse drain valve 28 and closing the chemical supply valve 14 and the purified water extraction valve 23, the raw water taken into the system can be directly drained without passing through the filtration part 2 and the chemical supply part 3. Also in this case, the direct drain valve 71 should be opened.

[0047] Also, by opening the backwash water supply valve 81 and the purified water extraction valve 23 and closing the chemical supply valve 14 and the rinse drain valve 28, the raw water taken into the system can also be directly taken out without passing through the filtration part 2 and the chemical supply part 3.

[0048] Next, the most characteristic configuration of the present invention will be described. In the water treatment apparatus 1 of the present embodiment, as described above, a bypass drainage branch portion 90 that divides the flow of raw water is provided in the path of the raw water inflow pipe 10 upstream of the chemical supply unit 3. The bypass drainage branch portion 90 branches and connects one to the filtration unit 2 via the raw water inflow pipe 10 and the other to the surplus drainage pipe 92 via the flow rate adjustment unit 91. The flow rate adjustment unit 91 discharges water to the downstream side of the surplus drainage pipe 92 by opening the internal valve mechanism when raw water having a pressure equal to or higher than a predetermined pressure flows in from the upstream side.

[0049] The raw water flowing during the filtration process may sometimes flow in exceeding the design flow rate. That is, during the filtration process, the raw water pumped from the electric pump 4 is supplied to the water treatment apparatus 1, but the water pressure supplied from the electric pump 4 may increase due to environmental changes such as changes in the water source of the electric pump 4. For example, when pumping water from a well, if the well water level rises due to heavy rain, the load on the electric pump 4 decreases. Then, the electric pump 4 supplies high-pressure raw water to the water treatment apparatus 1, the water level inside the chemical supply unit 3 rises, and chemicals with a concentration above the specified concentration may elute.

[0050] Thus, when a high pressure is applied to the raw water inflow pipe 10, as shown in FIG. 5, the flow rate adjustment unit 91 avoids a pressure increase by flowing the raw water to the surplus drainage pipe 92 side. That is, when high-pressure raw water is supplied to the water treatment apparatus 1, in addition to the flow during the above-described filtration process, the surplus raw water branched at the bypass drainage branch portion 90 in the raw water inflow pipe 10 passes through the flow rate adjustment unit 91 and is drained to the backwash drain port 41 through the surplus drainage pipe 92. In this way, the raw water can be branched at the bypass drainage branch portion 90 to suppress the amount of water flowing into the chemical supply unit 3 and the filtration unit 2 within a desired range. Due to the branching by the bypass drainage branch portion 90, the raw water branches and flows into the main flow path and the drainage flow path as follows.

[0051] [Main flow path] Raw water inlet 11 → (Raw water inflow pipe 10) → Branch portion 12 → Bypass drainage branch portion 90 → Chemical supply unit 3 → Branch portion 13 → Filtration unit 2 → (Purified water discharge pipe 20) → Branch portion 22 → Purified water outlet 21 [Drainage flow path] Raw water inlet 11 → (Raw water inflow pipe 10) → Branch part 12 → Bypass drainage branch part 90 → Flow rate adjustment part 91 → Surplus drain pipe 92 → (Backwash drain pipe 40) → Backwash drain port 41 In this way, in the drainage path, the raw water supplied in excess due to external influence is discharged, and in the main flow path, after being purified by the filtration unit 2, it is supplied to the clean water tank.

[0052] In this embodiment, the surplus drain pipe 92 is connected to the backwash drain port 41, but the surplus raw water may be directly drained outside the system of the water treatment device 1 from the surplus drain pipe 92. Also, although the bypass drainage branch part 90 is provided in the raw water inflow pipe 10, as long as it is an internal pipe of the water treatment device 1, since the pressure of all the connected pipes can be reduced, it may be connected to the pipe where the pressure is desired to be directly reduced. For example, the surplus drain pipe 92 may be provided in the front stage of the branch part 12 or in the rear stage of the chemical supply valve 14.

[0053] Next, the flow rate adjustment part 91 will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view of the flow rate adjustment part 91.

[0054] As described above, the flow rate adjustment part 91 is provided in the surplus drain pipe 92 and adjusts the flow rate of the surplus raw water diverted from the bypass drainage branch part 90. The flow rate adjustment part 91 has an adjustment part base 93, an adjustment part cover 94 attached to the upper part thereof, and a diaphragm 95 sandwiched between the adjustment part base 93 and the adjustment part cover 94. The diaphragm 95 is fixed to the valve 97. Normally, it is pressed against the valve seat 98 by the reaction force of the spring 96 to close the flow path. The lower surface of the spring 96 is in contact with the valve 97, and the upper surface of the spring 96 is in contact with the adjustment part cover 94. When the pressure in the inflow pipe 99 rises, the valve 97 is pushed up, the inflow pipe 99 and the outflow pipe 100 are connected in communication, the flow path is opened, and the surplus raw water is discharged from the surplus drain pipe 92. In this way, the surplus raw water flowing into the flow rate adjustment part 91 is drained into the surplus drain pipe 92, thereby reducing the pressure of the water treatment device 1.

[0055] Since the diaphragm 95 is on the flow path of the water treatment device 1, it is advisable to select a rubber material with chemical resistance, such as fluororubber or silicone rubber. Also, it is good to select a spring constant of the spring 96 of about 0.5 - 20 N / mm.

Industrial Applicability

[0056] The water treatment device according to the present invention can supply a sufficient amount of clean backwash water for backwashing and can be installed in a space-saving manner compared to conventional products. Therefore, it is useful as a small household water treatment device used for purifying well water or stored water.

Explanation of Reference Numerals

[0057] 1 Water treatment device 2 Filtration section 3 Chemical supply section 4 Electric pump 10 Raw water inflow pipe 11 Raw water inlet 12 Branch section 13 Branch section 14 Chemical supply valve 20 Purified water discharge pipe 21 Purified water outlet 22 Branch section 23 Purified water extraction valve 24 Throttle section 26 Branch section 27 Rinse drain pipe 28 Rinse drain valve 29 Rinse drain port 31 Inflow path 32 Chemical path 33 Bypass path 34 Outflow path 40 Backwash drain pipe 41 Backwash drain port 42 Backwash valve 43 Air supply valve 51 Housing 51a Base 51b Upper cover 52 Ejection pipe 53 Chemical placement section 54 Recovery section 55 Recovery Opening 58 Placement Part Exit 60 Water-Soluble Solid Agent 62 Check Valve 70 Direct Drain Pipe 71 Direct Drain Valve 80 Backwash Water Supply Pipe 81 Backwash Water Supply Valve 90 Bypass Drainage Branch Part 91 Flow Regulating Part 92 Surplus Drain Pipe 93 Regulating Part Base 94 Regulating Part Cover 95 Diaphragm 96 Spring 97 Valve 98 Valve Seat 99 Inflow Pipe 100 Outflow Pipe

Claims

1. a filtration section containing a filter medium; a raw water inflow pipe connected to the filtration section; a chemical supply section provided upstream of the filtration section in the raw water inflow pipe for adding a chemical to the raw water flowing in the path of the raw water inflow pipe; a purified water discharge pipe for taking out the purified raw water after filtration from the filtration section; an excess drain pipe for draining a part of the raw water flowing in the path of the raw water inflow pipe toward the chemical supply section, and having: the filtered section into which the raw water added with the chemical flows; a bypass drainage branch section is provided in the path of the raw water inflow pipe, which is connected to the excess drain pipe from the upstream side of the chemical supply section; a flow rate adjustment section for adjusting the drainage volume flowing from the bypass drainage branch section to the excess drain pipe, the flow rate adjustment section having a valve that opens when the pressure of the raw water flowing through the raw water inflow pipe exceeds a predetermined value. A water treatment device.

2. The water treatment device according to claim 1, wherein the flow rate adjustment section is a two-way valve that opens and closes a flow path by a diaphragm inside.

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