Automatic drainage device

Abstract

To provide an automatic drainage device that can suppress water pressure fluctuations when the main valve is opened and closed. [Solution] The configuration includes a wastewater pipe 5 extending from the water pipe 3 to the drainage system 4, a main valve 6 that controls the flow of water through the wastewater pipe 5, and a water pressure fluctuation suppression unit 7 that suppresses fluctuations in water pressure within the wastewater pipe 5 due to the opening and closing of the main valve 6.

Description

Technical Field

[0001] This invention relates to an automatic drainage device installed together with a water pipe.

Background Art

[0002] In order to ensure the sanitary condition of the tap water flowing through the water pipe, it is obligatory to ensure a free residual chlorine concentration of 0.1 mg / L or more at the end of the pipeline. However, when stagnation occurs at the end of the pipeline or the like, there is a problem that the free residual chlorine concentration decreases with the passage of time and the water quality deteriorates.

[0003] To solve this problem, it is conceivable to constantly drain the water at the end of the pipeline or for workers to manually perform drainage work regularly. However, waste of tap water and an increase in work costs become new problems. Therefore, for example, in Patent Document 1 below, by periodically draining the stagnant water using an automatic drainage device that does not require external power that can be continuously used with little maintenance, while suppressing waste of tap water and an increase in work costs associated with maintaining water quality, the free residual chlorine concentration is maintained at an appropriate value.

[0004] The automatic drainage device has a waste water pipeline extending from the water pipe to a drainage system (such as a drainage ditch provided on the ground or underground), and controls the flow of water in the waste water pipeline by opening and closing a main valve (for example, a solenoid valve) provided on this waste water pipeline.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When the water pipe capacity is large or the rate of decrease in residual chlorine concentration is significant, it is necessary to replace a large amount of stagnant water, so there is a tendency to set the drainage flow rate higher. However, when the drainage flow rate is high, sudden water pressure fluctuations occur when the main valve is opened and closed, which may cause malfunctions in the equipment installed in the wastewater pipe.

[0007] Therefore, the objective of this invention is to suppress water pressure fluctuations when the main valve of an automatic drainage device is opened and closed. [Means for solving the problem]

[0008] To solve the above problems, this invention provides: Disposal pipelines extending from the water pipes to the drainage system, A main valve that controls the flow of water through the aforementioned wastewater pipeline, A water pressure fluctuation suppression unit that suppresses fluctuations in water pressure in the drainage pipeline caused by the opening and closing of the main valve, An automatic drainage system having the following was constructed (first configuration).

[0009] In this way, the water pressure fluctuation suppression unit can suppress water pressure fluctuations when the main valve is opened and closed.

[0010] In the first configuration, the water pressure fluctuation suppression unit can be configured as a water hammer arrestor (second configuration), or the water pressure fluctuation suppression unit can be configured to have a bypass pipeline connecting the upstream and downstream sides of the main valve so as to bypass the main valve, and a bypass valve provided in the bypass pipeline (third configuration). In this way, water pressure fluctuations can be suppressed at low cost and in a simple manner by the action of the water hammer arrestor, or the bypass pipeline and bypass valve.

[0011] In the third configuration, the water pressure fluctuation suppression unit further includes a control unit that controls the opening and closing of the main valve and the bypass valve, and the main valve and the bypass valve are controlled so that when the main valve is closed, the start of closing of the bypass valve is delayed compared to the start of closing of the main valve, or the main valve and the bypass valve are controlled so that when the main valve is opened, the start of opening of the main valve is delayed compared to the start of opening of the bypass valve (fourth configuration). In this way, by opening and closing the main valve and the bypass valve with a time difference, water pressure fluctuations associated with the opening and closing of the main valve can be mitigated.

[0012] In the fourth configuration, the main valve and the bypass valve can be controlled such that when the main valve is closed, the bypass valve starts closing only after the main valve has completely closed, or when the main valve is opened, the bypass valve starts opening only after the bypass valve has completely opened (fifth configuration). In this way, immediately after closing or opening the main valve, when the water pressure fluctuation associated with the opening and closing of the main valve is at its maximum, the water pressure can be quickly released through the bypass pipeline. [Effects of the Invention]

[0013] In this invention, a water pressure fluctuation suppression unit is provided in the automatic drainage device, and the action of this water pressure fluctuation suppression unit makes it possible to suppress water pressure fluctuations when the valve body of the automatic drainage device is opened and closed. [Brief explanation of the drawing]

[0014] [Figure 1] Front view showing the automatic drainage device according to the first embodiment of this invention installed in an underground space (manhole). [Figure 2] Plan view of an automatic drainage device according to the first embodiment of this invention [Figure 3] Front view of the automatic drainage system shown in Figure 2. [Figure 4] Perspective view of the automatic drainage system shown in Figure 2. [Figure 5] A plan view showing a modified example of the automatic drainage system shown in Figure 2. [Figure 6]Plan view showing an existing automatic drainage device [Figure 7] Plan view of the state where a T-shaped pipe for attaching a water hammer arrester to the automatic drainage device shown in Fig. 6 is provided [Figure 8] Plan view of the automatic drainage device according to the second embodiment of this invention [Figure 9] Front view of the automatic drainage device shown in Fig. 8 [Figure 10] Perspective view of the automatic drainage device shown in Fig. 8

Mode for Carrying Out the Invention

[0015] A first embodiment of the automatic drainage device 1 according to this invention will be described based on the drawings. As shown in Fig. 1, the automatic drainage device 1 is provided in an underground space S (in this embodiment, a manhole. Hereinafter, the underground space S will be referred to as a manhole, and the same reference numeral as the underground space S will be used). In this manhole S, a controller box 2 in which equipment for controlling the automatic drainage device 1 is housed is provided. The controller box 2 is attached at a relatively high position (a position where there is almost no risk of being submerged) in the manhole S, such as lifting means (such as a ladder, not shown) for ascending and descending in the manhole S.

[0016] The automatic drainage device 1 is a device for automatically draining water (stagnant water) in a water pipe 3 laid underground to a drainage system 4 (such as a side ditch) on the ground or underground. As shown in Figs. 2 to 4, a drainage pipe 5 extending from the water pipe 3 to the drainage system 4, a main valve 6 provided in the underground space S where the drainage pipe 5 is piped for controlling the water flow through the drainage pipe 5, and a water pressure fluctuation suppression unit 7 for suppressing fluctuations in the water pressure in the drainage pipe 5 accompanying the opening and closing of the main valve 6.

[0017] The main valve 6 is a solenoid valve that is opened and closed (switched between a water flow state and a shut-off state) by a control unit 8 provided within the controller box 2. The main valve 6 is provided with dust and water protection performance of about IP67 to prepare for temporary water adhesion and short-term submersion. However, in order to avoid submersion as much as possible and to facilitate maintenance work, it is provided at the highest position of the drain pipe 5 that is piped while bending within the manhole S.

[0018] In the first embodiment, a commercially available water hammer arrester 7a is adopted as the water pressure fluctuation suppression unit 7. This water hammer arrester 7a is attached to the branch pipe portions of the T-shaped pipes 9A, 9B, 9C, and 9D provided in the drain pipe 5. In FIGS. 2 to 4, for the purpose of testing to confirm the effect of the water hammer arrester 7a, a configuration is adopted in which T-shaped pipes 9A, 9B, 9C, and 9D are provided at four locations on the upstream side of the main valve 6, and a state in which the water hammer arrester 7a is provided at one of them (T-shaped pipe 9D) is shown. When a plurality of T-shaped pipes 9A, 9B, 9C, and 9D are provided, the branch pipe portions of the unused T-shaped pipes 9A, 9B, 9C, and 9D are sealed using a sealing member (not shown). The number of T-shaped pipes 9A, 9B, 9C, and 9D provided in the drain pipe 5 can be appropriately determined according to the number of water hammer arresters 7a actually to be attached, and for example, as shown in FIG. 5, it can be set to only one location.

[0019] The drain pipe 5 is provided with a stopcock 10, a water sampling valve 11, and a water meter 12 in order from its upstream side. The stopcock 10 is a manual valve for switching between a water flow state and a shut-off state between the water supply pipe 3 and the drain pipe 5. The water sampling valve 11 is a valve for sampling the water flowing through the drain pipe 5. After sampling water from the water sampling valve 11, a water quality inspection of the water flowing through the drain pipe 5 is performed. The water meter 12 is a device for measuring the flow rate of the water flowing through the drain pipe 5. By grasping the drainage flow rate during drainage through this measurement, the operation confirmation of the automatic drainage device 1 and the management of the drainage flow rate are performed.

[0020] This water hammer arrestor 7a can be installed, for example, by newly installing a T-shaped pipe 9A in a part of the wastewater pipe 5 of an existing automatic drainage device 1' shown in Figure 6, as shown in Figure 7. In other words, an existing automatic drainage device 1' can be modified into the automatic drainage device 1 according to this invention.

[0021] A second embodiment of the automatic drainage device 1 according to this invention will be described based on the drawings. As shown in Figures 8 to 10, the automatic drainage device 1 according to the second embodiment differs from the automatic drainage device 1 according to the first embodiment in the configuration of the water pressure fluctuation suppression unit 7, but the other configurations are the same. In the following, only the configuration of the water pressure fluctuation suppression unit 7 will be described.

[0022] The water pressure fluctuation suppression unit 7 according to the second embodiment includes a bypass pipeline 7b that connects the upstream and downstream sides of the main valve 6 so as to bypass the main valve 6, and a bypass valve 7c provided in the bypass pipeline 7b. The bypass valve 7c is a solenoid valve whose opening and closing control (switching between a water-flow state and a shut-off state) is controlled by a control unit 8 provided in the controller box 2, similar to the main valve 6, and is positioned at approximately the same height as the main valve 6 (a height that minimizes submersion and facilitates maintenance work).

[0023] The opening and closing of the main valve 6 and the bypass valve 7c are performed with a time difference. Specifically, when the main valve 6 is closed, the main valve 6 and the bypass valve 7c are controlled so that the start of the closing of the bypass valve 7c is delayed compared to the start of the closing of the main valve 6. Similarly, when the main valve 6 is opened, the main valve 6 and the bypass valve 7c are controlled so that the start of the opening of the main valve 6 is delayed compared to the start of the opening of the bypass valve 7c. In particular, in this embodiment, when the main valve 6 is closed, the bypass valve 7c is controlled so that the closing of the bypass valve 7c is started only after the closing of the main valve 6 is completely finished. Similarly, when the main valve 6 is opened, the main valve 6 and the bypass valve 7c are controlled so that the opening of the main valve 6 is started only after the opening of the bypass valve 7c is completely finished.

[0024] The water hammer generated in the drainage pipeline 5 when the main valve 6 opens and closes reaches its maximum immediately after the opening and closing is completed. Therefore, by operating the bypass valve 7c and the main valve 6 in conjunction with a short time difference, the water hammer generated when the main valve 6 opens and closes can be effectively released through the bypass pipeline 7b.

[0025] The valves 6 and 7c are selected and their flow rates are adjusted so that the flow rate of wastewater passing through the main valve 6 is greater than the flow rate of wastewater passing through the bypass valve 7c. In this embodiment, the flow rate of the main valve 6 is set to 30 L / min, and the flow rate of the bypass valve 7c is set to 5 L / min. The flow rate of the main valve 6 is determined within a range that allows for the rapid elimination of stagnation in the water pipe 3 while reducing the water hammer associated with the opening and closing of the main valve 6 through the action of the bypass valve 7c, taking into consideration various conditions such as the water pressure at the installation site, the length of the piping before and after the main valve, and the material of the piping. The flow rate of the bypass valve 7c is determined within a range that minimizes the water hammer associated with the opening and closing of the main valve 6 while preventing water hammer from occurring due to the opening and closing of the bypass valve 7c itself.

[0026] In this embodiment, the ratio of the flow rate of the main valve 6 to the flow rate of the bypass valve 7c is 6:1, but this can be appropriately determined depending on conditions such as the water pressure at the installation site, the length and diameter of the piping before and after the valve, and the material of the piping.

[0027] Table 1 shows the results of evaluation tests for the water pressure fluctuation suppression effect of the automatic drainage device 1 according to this invention. Examples are shown for the case in which a water hammer arrestor 7a is used as the water pressure fluctuation suppression unit 7 (first embodiment) and the case in which a bypass pipe 7b and a bypass valve 7c are used (second embodiment).

[0028] In the configuration employing the water hammer arrester 7a, the water hammer arrester 7a was installed in one or two of the four T-joints 9A, 9B, 9C, and 9D shown in Figures 2 to 4. All of the T-joints 9A, 9B, 9C, and 9D are located upstream of the main valve 6, with T-joint 9D being closest to the main valve 6 and T-joint 9A being furthest away. In the configuration employing the bypass pipeline 7b and bypass valve 7c, the control unit 8 controlled the closing of the main valve 6 and the bypass valve 7c so that the closing of the bypass valve 7c began immediately after the closing of the main valve 6 was completely finished.

[0029] As a comparative example, a standard automatic drainage device 1' (see Figure 6) without the water pressure fluctuation suppression unit 7 according to this invention was used. It was confirmed in advance that there was no significant difference between the example and the comparative example in the water pressure in the drainage pipe 5 immediately before the main valve 6 was closed.

[0030] [Table 1]

[0031] In the standard automatic drainage device 1' (comparative example), the water pressure fluctuation amplitude (fluctuation amplitude towards the positive pressure side) immediately after closing the main valve 6 was a slightly high value of 0.22 MPa. In this case, there is a high risk of water hammer occurring immediately after closing the main valve 6.

[0032] In contrast, when a water hammer arrester 7a was adopted as the water pressure fluctuation suppression unit 7, the amplitude of the water pressure fluctuation immediately after closing the main valve 6 was significantly lower than that of the standard automatic drainage device 1', ranging from 0.12 to 0.15 MPa, confirming that water hammer immediately after closing the main valve 6 could be suppressed. The installation position and number of water hammer arresters 7a did not significantly affect the effect of reducing the amplitude of the water pressure fluctuation.

[0033] Furthermore, when the bypass pipeline 7b and bypass valve 7c are used as the water pressure fluctuation suppression unit 7, the amplitude of the water pressure fluctuation immediately after closing the main valve 6 is 0.13 MPa, which is significantly lower than that of the standard automatic drainage device 1'. This confirms that water hammer can be suppressed immediately after closing the main valve 6, similar to the case where the water hammer prevention unit 7a is used. In this embodiment, the control unit 8 controlled the closing of the main valve 6 and the bypass valve 7c so that the closing of the bypass valve 7c started immediately after the closing of the main valve 6 was completely finished. However, as long as the main valve 6 and the bypass valve 7c are controlled so that the start of the closing of the bypass valve 7c is delayed compared to the start of the closing of the main valve 6, the timing of the closing of each valve 6 and 7c can be changed while confirming the water hammer suppression effect.

[0034] In the above test, we evaluated the suppression of water hammer fluctuations that occur when the main valve 6 is closed. However, it is possible that water hammer that occurs when the main valve 6 is open can also be reduced by employing the water pressure fluctuation suppression unit 7 of this invention.

[0035] The automatic drainage device 1 according to this invention is equipped with a water pressure fluctuation suppression unit 7 (water hammer arrestor 7a, or bypass pipeline 7b and bypass valve 7c), which makes it possible to suppress water pressure fluctuations when the main valve 6 is opened and closed in a low cost and in a simple manner.

[0036] Furthermore, in a configuration where the water pressure fluctuation suppression unit 7 has a bypass pipeline 7b and a bypass valve 7c, the main valve 6 and the bypass valve 7c are controlled such that when the main valve 6 is closed, the start of closing of the bypass valve 7c is delayed compared to the start of closing of the main valve 6, or when the main valve 6 is opened, the start of opening of the main valve 6 is delayed compared to the start of opening of the bypass valve 7c. As a result, water pressure fluctuations associated with the opening and closing of the main valve 6 can be mitigated by the bypass valve 7c, which opens and closes with a time lag from the main valve 6.

[0037] In particular, the main valve 6 and the bypass valve 7c are controlled such that when the main valve 6 is closed, the bypass valve 7c starts closing only after the main valve 6 has completely closed, or when the main valve 6 is opened, the bypass valve 7c starts opening only after the main valve 6 has completely opened. As a result, immediately after closing or opening the main valve 6, when the water pressure fluctuation associated with the opening and closing of the main valve 6 is at its maximum, the water pressure can be quickly released via the bypass pipeline 7b.

[0038] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. While the description states that when the main valve 6 is closed, the bypass valve 7c begins to close only after the main valve 6 has completely closed, and when the main valve 6 is opened, the bypass valve 7c begins to open only after the bypass valve 7c has completely opened, the invention is not limited thereto. The main valve 6 and the bypass valve 7c can be closed or opened with a time delay even when they are not completely closed or open. Therefore, the scope of the invention is indicated by the claims rather than the above description, and is intended to include the meaning of equivalents of the claims and all modifications thereof.

[0039] For example, in the above embodiment, the case in which the water pipe 3 is laid underground and the automatic drainage device 1 is installed in an underground space S was described, but the present invention can also be applied when the water pipe 3 is laid above ground or when the automatic drainage device 1 is installed above ground. [Explanation of symbols]

[0040] 1 Automatic drainage device 2 Controller Box 3. Water pipes 4. Drainage system 5 Waste water pipe 6. Main valve 7. Water pressure fluctuation suppression unit 7a Water hammer arrester 7b Bypass conduit 7c Bypass valve 8 Control Unit 9A, 9B, 9C, 9D T-tube 10. Shut-off valve 11 Water intake valve 12 Water meter S Underground space (manhole)

Claims

1. A drainage pipeline (5) extends from the water pipe (3) to the drainage system (4), A main valve (6) that controls the flow of water through the aforementioned wastewater pipeline (5), A water pressure fluctuation suppression unit (7) that suppresses fluctuations in water pressure in the drainage pipe (5) due to the opening and closing of the main valve (6), An automatic drainage device having the following features.

2. The automatic drainage device according to claim 1, wherein the water pressure fluctuation suppression unit (7) is a water hammer arrestor (7a).

3. The automatic drainage device according to claim 1, wherein the water pressure fluctuation suppression unit (7) comprises a bypass pipe (7b) connecting the upstream and downstream sides of the main valve (6) so as to bypass the main valve (6), and a bypass valve (7c) provided in the bypass pipe (7b).

4. The automatic drainage device according to claim 3, wherein the water pressure fluctuation suppression unit (7) further comprises a control unit (8) that controls the opening and closing of the main valve (6) and the bypass valve (7c), and when the main valve (6) is closed, the main valve (6) and the bypass valve (7c) are controlled such that the start of closing of the bypass valve (7c) is delayed compared to the start of closing of the main valve (6), or when the main valve (6) is opened, the main valve (6) and the bypass valve (7c) are controlled such that the start of opening of the main valve (6) is delayed compared to the start of opening of the bypass valve (7c).

5. The automatic drainage device according to claim 4, wherein the main valve (6) and the bypass valve (7c) are controlled such that when the main valve (6) is closed, the bypass valve (7c) is closed only after the closing of the main valve (6) is completely finished, or when the main valve (6) is opened, the bypass valve (7c) is opened only after the opening of the main valve (7c) is completely finished.

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