Water level detection device, water level monitoring system, and inspection method for a water level monitoring system
The water level detection device simulates water levels using air pressure manipulation, addressing electrode detachment detection and system verification without water changes, ensuring safe and efficient maintenance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI ELECTRIC BUILDING SOLUTIONS CORP
- Filing Date
- 2022-12-28
- Publication Date
- 2026-05-22
AI Technical Summary
Conventional water level detection devices and monitoring systems require manual short-circuiting of electrode rods to simulate full and reduced water levels for maintenance, which does not detect electrode detachment and necessitate visual inspection, risking tool fall and water loss.
A water level detection device with a tubular member, electrode rods, and communication passages that allow air pressure manipulation to simulate water levels without physical water changes, enabling detection of electrode detachment without visual inspection.
Detects electrode detachment and verifies system functionality without water supply or drainage, ensuring safe and efficient maintenance.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a water level detection device for detecting the water level of a water receiving tank, a water level monitoring system, and a method for inspecting the water level monitoring system.
Background Art
[0002] Conventionally, there is known a water level detection device that is held by a holder fixed to the upper wall (ceiling) of a water receiving tank and detects the water level in the water receiving tank based on the energization state between a plurality of electrode rods having different lengths (see, for example, Japanese Patent Application Laid-Open No. 11-190050 (Patent Document 1)). Further, there is known a water level monitoring system for supplying and discharging water in the water receiving tank according to a change in the water level detected by the water level detection device. When the water level detection device detects that the water level in the water receiving tank has reached the full water level, the water level monitoring system outputs an alarm signal from the system to a monitoring device or the like, and when the water level detection device detects that the water level in the water receiving tank has reached the reduced water level, water is supplied into the water receiving tank.
[0003] Originally, during maintenance of the water level detection device and the water level monitoring system, it is preferable to confirm whether water supply and drainage into the water receiving tank and output of an alarm signal are appropriately performed in each state, with at least the state where the water level in the water receiving tank has reached the full water level and the state where the water level in the water receiving tank has reached the reduced water level realized. However, in such a method, it is necessary to supply and discharge a large amount of water into the water receiving tank only for the purpose of maintenance.
[0004] Therefore, during maintenance of the conventional water level detection device and water level monitoring system, generally, without actually changing the water level in the water receiving tank to the full water level and the reduced water level, a plurality of terminals arranged outside the water receiving tank and connected to each of the plurality of electrode rods are short-circuited to pseudo-create at least the above two states, and it is confirmed whether water supply and drainage into the water receiving tank are appropriately performed in each state.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
[0006] The maintenance method described above alone cannot detect the anomaly that at least one of the electrode rods has detached from the upper wall.
[0007] Therefore, when using the above maintenance method, it is necessary to open the lid of the water tank and visually inspect the inside of the tank. In this case, there is a risk that maintenance tools or other equipment may fall into the water tank.
[0008] The main object of the present invention is to provide a water level detection device, a water level monitoring system, and a method for inspecting a water level monitoring system that can detect an abnormality in which at least one of the electrode rods has fallen off the upper wall without visually inspecting the inside of a water tank. [Means for solving the problem]
[0009] The water level detection device according to the present invention is a water level detection device for detecting the water level in a water tank, and comprises a tubular member disposed in the water tank and having an upper end that is airtightly fixed to the upper wall of the water tank and an opening that opens into the water tank, a plurality of electrode rods disposed inside the tubular member in the water tank, a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water tank, and at least one communication passage that connects the inside of the tubular member to the outside of the water tank via the upper wall and the part of the holding part that faces the inside of the tubular member.
[0010] The water level monitoring system according to the present invention comprises a water level monitoring device that supplies water to and drains water from a water tank according to the water level in the water tank detected by the water level detection device.
[0011] The method for inspecting a water level monitoring system according to the present invention is a method for inspecting a water level monitoring system comprising a water level detection device for detecting the water level in a water tank and a water level monitoring device for supplying and draining water to and from the water tank according to the water level in the water tank detected by the water level detection device. The water level detection device comprises a tubular member disposed in the water tank, a plurality of electrode rods disposed inside the tubular member in the water tank, and a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water tank. The tubular member has an upper end that is airtightly fixed to either the upper wall of the water tank or the holding part, and an opening that opens into the water tank. The water level detection device further comprises a communication passage that connects the inside of the tubular member to the outside of the water tank via the upper wall and the portion of the holding part that faces the inside of the tubular member. The method comprises a step of changing the water level inside the tubular member by supplying air to the inside of the tubular member or exhausting air from the inside of the tubular member via the communication passage, and confirming the response of the water level monitoring device. [Effects of the Invention]
[0012] According to the present invention, it is possible to provide a water level detection device, a water level monitoring system, and a method for inspecting a water level monitoring system that can detect an abnormality, such as at least one electrode rod having fallen off the upper wall, without visually inspecting the inside of a water tank. [Brief explanation of the drawing]
[0013] [Figure 1] This is a cross-sectional view illustrating the normal operation of the water level detection device and water level monitoring system according to this embodiment. [Figure 2] Figure 1 is a perspective view showing the tubular member of the water level detection device. [Figure 3] This is a plan view showing the holding section of the water level detection device shown in Figure 1. [Figure 4] This is a cross-sectional view illustrating the maintenance and inspection process for the water level detection device and water level monitoring system according to this embodiment. [Figure 5] This is a cross-sectional view illustrating the maintenance and inspection process for the water level detection device and water level monitoring system according to this embodiment. [Figure 6]This is a cross-sectional view illustrating that an abnormality, such as the electrode rod becoming detached, may be detected during maintenance and inspection of the water level detection device and water level monitoring system according to this embodiment. [Figure 7] This is a cross-sectional view illustrating the normal operation of a water level detection device and water level monitoring system according to a first modified example of this embodiment. [Figure 8] This is a cross-sectional view illustrating the normal operation of a water level detection device and water level monitoring system according to a second modified example of this embodiment. [Modes for carrying out the invention]
[0014] The water level detection device according to this embodiment is a water level detection device that detects the water level in a water tank. The water tank to which the water level detection device according to this embodiment is applied is not particularly limited, as long as it is positioned above the full water level of the tank and has an upper wall that extends in a direction intersecting the direction of gravity.
[0015] <Configuration of the water receiving tank> First, an example of a water receiving tank 100 will be described with reference to Figure 1. As shown in Figure 1, the water receiving tank 100 has, for example, an upper wall 101, a lower wall, and side walls. A water inlet 102 is formed above the side wall, and a drain outlet 103 is formed below the side wall. The upper wall 101 is positioned above the full water level of the water receiving tank 100 and is a wall portion that extends in a direction intersecting the direction of gravity G. A first opening 101A is formed in the upper wall 101, which connects the inside and outside of the water receiving tank 100. The water receiving tank 100 further has a lid portion 120 that can open and close the first opening 101A. The first opening 101A is provided for workers to enter and exit the inside of the water receiving tank.
[0016] The upper wall 101 has at least one second opening 101B that connects the inside and outside of the water tank 100. The at least one second opening 101B is provided for the placement of the holding part 3 of the water level detection device 10, which will be described later.
[0017] A water supply pipe is connected to the water supply port 102. A drain pipe is connected to the drain port 103.
[0018] The pressure of the space filled with air inside the water receiving tank 100 is set to atmospheric pressure regardless of the up and down movement of the water level in the water receiving tank 100. The water receiving tank 100 is formed with an air vent hole (not shown) to allow air to enter and exit between the space filled with air inside the water receiving tank 100 and the outside of the water receiving tank 100.
[0019] <Configuration of the water level detection device> As shown in FIG. 1, the water level detection device 10 according to the present embodiment includes a tubular member 1, a plurality of electrode rods 2, a holding portion 3, a first communication path 4, a second communication path 5, a plurality of terminals 6, a case 7, a closing member 8, and a compressor 9. The water level detection device 10 is provided such that the water level inside the tubular member 1 is at the same position as the water level outside the tubular member 1 inside the water receiving tank 100 during normal operation.
[0020] The tubular member 1 is disposed in the water receiving tank 100 and has an upper end portion 1A that is airtightly fixed to the upper wall 101 of the water receiving tank 100 and a third opening portion 1B that opens into the water receiving tank 100. The upper end portion 1A is, for example, airtightly fixed to the holding portion 3, and since the holding portion 3 is airtightly fixed to the upper wall 101, it is airtightly fixed to the upper wall 101. The method of fixing the upper end portion 1A to the holding portion 3 is not particularly limited. The upper end portion 1A is fixed to the holding portion 3 by, for example, an adhesive. The third opening portion 1B of the tubular member 1 is provided, for example, at the lower end portion of the tubular member 1. The upper end portion 1A of the tubular member 1 is disposed so as to surround the second opening portion 101B. The third opening portion 1B of the tubular member 1 is disposed below the lowered water level of the water receiving tank 100. The tubular member 1 does not have an opening that communicates the inside and the outside of the tubular member 1 between the third opening portion 1B and the upper end portion 1A. From a different perspective, the tubular member 1 is provided such that the water or air inside the water receiving tank 100 enters and exits between the inside and the outside of the tubular member 1 only through the third opening portion 1B.
[0021] Multiple electrode rods 2 are arranged inside the tubular member 1 within the water receiving tank 100. The multiple electrode rods 2 include, for example, a first electrode rod 21, a second electrode rod 22, a third electrode rod 23, a fourth electrode rod 24, and a fifth electrode rod 25. The first electrode rod 21 is a full water level detection electrode rod for detecting when the water level in the water receiving tank 100 is at the full water alarm level (hereinafter also simply referred to as the full water level). The length of the first electrode rod 21 in the extending direction is the shortest of the multiple electrode rods 2. The second electrode rod 22 is an electrode rod for detecting when the water level in the water receiving tank 100 is at the water supply stop level. The length of the second electrode rod 22 in the extending direction is longer than that of the first electrode rod 21 and is the second shortest of the multiple electrode rods 2. The third electrode rod 23 is an electrode rod for detecting when the water level in the water receiving tank 100 is at the water supply start level. The length of the third electrode rod 23 in the extending direction is longer than that of the second electrode rod 22 and shorter than that of the fourth electrode rod 24. The fourth electrode rod 24 is an electrode rod for detecting the low water level, used to detect when the water level in the water tank 100 is at the low water level alarm level (hereinafter also simply referred to as the low water level). The length of the fourth electrode rod 24 in the extending direction is shorter than that of the fifth electrode rod 25, making it the second longest of the multiple electrode rods 2. The fifth electrode rod 25 is a common electrode rod. The length of the fifth electrode rod 25 in the extending direction is the longest of the multiple electrode rods 2. The length between the upper end 1A of the tubular member 1 and the third opening 1B is equal to or greater than the length of the fifth electrode rod 25 in the extending direction, which is the longest of the multiple electrode rods 2. The lower end of the fifth electrode rod 25 is positioned below the low water level of the water tank 100. In other words, the third opening 1B of the first tubular member 1 is positioned below the low water level of the water tank 100.
[0022] The upper portion of each of the multiple electrode rods 2 is held by a holding portion 3. The upper end of each of the multiple electrode rods 2 is electrically connected to multiple terminals 6 fixed to the holding portion 3. The lower end of each of the multiple electrode rods 2 is located inside the tubular member 1.
[0023] The holding part 3 holds multiple electrode rods 2. The holding part 3 is fixed to the second opening 101B. The holding part 3, for example, closes the second opening 101B.
[0024] The first connecting passage 4 and the second connecting passage 5 are provided to connect the inside of the tubular member 1 with the outside of the water tank 100 via the portion of the upper wall 101 that faces the inside of the tubular member 1. The first connecting passage 4 and the second connecting passage 5 are composed of, for example, through holes that penetrate the holding portion 3. The first connecting passage 4 and the second connecting passage 5 are provided to allow air to enter and exit between the upper space filled with air inside the tubular member 1 and the outside of the water tank 100 when the water level inside the tubular member 1 moves up and down during normal operation. As described above, the pressure in the space filled with air inside the water tank 100 is atmospheric pressure, regardless of the movement of the water level inside the water tank 100. Therefore, during normal operation, the upper space filled with air inside the tubular member 1 is maintained at atmospheric pressure, just like the space filled with air inside the water tank 100. As a result, during normal operation, the water level inside the tubular member 1 is at the same level as the water level inside the water tank 100 and outside the tubular member 1.
[0025] The first connecting passage 4 is closed by the closing member 8 during maintenance inspections (see Figure 4), as described later. The second connecting passage 5 is connected to the compressor 9 during maintenance inspections. In the water level detection device 10 during normal operation shown in Figure 1, the first connecting passage 4 and the second connecting passage 5 are open, connecting the inside of the tubular member 1 to the outside of the water tank 100. The second connecting passage 5 may also be connected to the compressor 9 during normal operation.
[0026] Multiple terminals 6 are fixed to the holding part 3 and are exposed on the upper surface of the holding part 3. Each of the multiple terminals 6 is electrically connected to the upper end of each of the multiple electrode rods 2 held by the holding part 3. Each of the multiple terminals 6 is electrically connected to the water level monitoring device 201 of the water level monitoring system 200, which will be described later.
[0027] Case 7 is positioned on the upper wall 101 of the water tank 100 so as to cover the upper ends of each of the multiple electrode rods 2, the holding portion 3, the first communication passage 4 and the second communication passage 5, and the multiple terminals 6. Case 7 is detachable from the upper wall 101.
[0028] As shown in Figure 2, the tubular member 1 is, for example, a cylindrical tube. Preferably, the tubular member 1 is transparent. Preferably, the material constituting the tubular member 1 is a transparent material, and more preferably polyvinyl chloride.
[0029] As shown in Figure 3, when the holding section 3 is viewed from above, the first communication passage 4 and the second communication passage 5 are arranged with a gap between them and the multiple electrode rods 2. However, the relative positions of the multiple electrode rods 2, the first communication passage 4, and the second communication passage 5 are not limited to those shown in Figure 3.
[0030] In the water level detection device 10 shown in Figure 4 for maintenance and inspection, the first communication passage 4 is airtightly closed by a closing member 8, and the second communication passage 5 is connected to the compressor 9. The closing member 8 can be any member capable of airtightly closing the first communication passage 4. The closing member 8 is detachable from the first communication passage 4. The closing member 8 may also be fixed to the first communication passage 4 and may be an on-off valve that opens or closes the first communication passage 4.
[0031] The compressor 9 is provided to supply air into the tubular member 1 to lower the water level inside the tubular member 1, or to exhaust air from the tubular member 1 to raise the water level inside the tubular member 1. Preferably, the compressor 9 is provided to supply air into the tubular member 1 to lower the water level inside the tubular member 1, and to exhaust air from the tubular member 1 to raise the water level inside the tubular member 1.
[0032] The compressor 9 is positioned on the upper wall 101 of the water tank 100 and outside the case 7, for example, during maintenance and inspection as shown in Figure 4. In this case, the pipeline connecting the compressor 9 and the second connecting passage 5 is routed through the case 7. The exhaust volume from the compressor 9 is set to allow switching between a state in which the first electrode rod 21 is submerged and a state in which the first electrode rod 21 is not submerged. The supply air volume from the compressor 9 is set to allow switching between a state in which the fourth electrode rod 24 is submerged and a state in which the fourth electrode rod 24 is not submerged.
[0033] The compressor 9 may be located inside the case 7. During normal operation as shown in Figure 1, the compressor 9 may be housed inside the case 7.
[0034] <Configuration of the water level monitoring system> As shown in Figure 1, the water level monitoring system 200 includes a water level detection device 10, a water level monitoring device 201 that supplies and drains water to and from the water tank 100 according to the water level in the water tank 100 detected by the water level detection device 10, a water supply channel, a first on-off valve 202 that opens and closes the water supply channel, and a drainage channel. The water level monitoring device 201 is electrically connected to each of the multiple terminals 6. Based on the electrical signals received from the multiple terminals 6, the water level monitoring device 201 transmits a signal to open and close the first on-off valve 202. The first on-off valve 202 opens and closes based on the signal received from the water level monitoring device 201. The first on-off valve 202 is, for example, a solenoid valve.
[0035] <Operation of the water level detection device and water level monitoring system> Next, the operation of the water level detection device 10 and the water level monitoring system 200 during normal operation will be described. During normal operation, the water level detection device 10 and the water level monitoring system 200 are in the state shown in Figure 1.
[0036] During normal operation, the water level monitoring system 200 supplies and drains water to the water tank 100 so that the water level in the water tank 100 is maintained between the water supply start level and the water supply stop level. During normal operation, the water level inside the tubular member 1 is at the same level as the water level in the water tank 100 and moves up and down in sync with the up and down movement of the water level in the water tank 100. When the water level in the water tank 100 drops, the water level inside the tubular member 1 also drops. When the water level in the water tank 100 reaches the water supply start level, the water level inside the tubular member 1 also reaches the water supply start level. As a result, the third electrode rod 23 of the water level detection device 10 is no longer submerged in water, and water supply to the water tank 100 begins. If the water level in the water tank 100 drops further below the water supply start level due to a problem with the water supply valve or the like, and the water level in the water tank 100 falls to a reduced level, the water level inside the tubular member 1 will also fall to a reduced level, and not only the third electrode rod 23 but also the fourth electrode rod 24 will no longer be submerged in water. When the water level monitoring device 201 detects that the fourth electrode rod 24 is not submerged in water, an alarm signal is output.
[0037] During normal operation, as the water level in the water tank 100 rises, the water level inside the tubular member 1 also rises. When the water level in the water tank 100 reaches the water supply stop level, the water level inside the tubular member 1 also reaches the water supply stop level. As a result, the second electrode rod 22 of the water level detection device 10 is submerged, the first shut-off valve 202 is closed, and the water supply to the water tank 100 is stopped. If the water level in the water tank 100 rises further than the water supply stop level due to a problem with the first shut-off valve 202 or the like, and the water level in the water tank 100 reaches the full water level, the water level inside the tubular member 1 also reaches the full water level, and the first electrode rod 21 of the water level detection device 10 is submerged. When the water level monitoring device 201 detects the submersion of the first electrode rod 21, an alarm signal is output.
[0038] <Inspection method for water level monitoring system> Next, the inspection method for the water level monitoring system 200 will be described. The inspection method for the water level monitoring system 200 includes the step of changing the water level inside the tubular member 1 by supplying air to the inside of the tubular member 1 or exhausting air from the inside of the tubular member 1 via the second communication passage 5, and confirming the response of the water level monitoring device 201. A specific example will be described below.
[0039] Firstly, as shown in Figures 4 and 5, the first communication passage 4 of the water level detection device 10 is closed by the closing member 8, and the second communication passage 5 is connected to the compressor 9. As a result, the compressor 9 supplies and exhausts air into the tubular member 1, allowing the water level inside the tubular member 1 to move up and down between the full water level and the low water level without supplying or draining water to the water tank 100.
[0040] Secondly, the compressor 9 supplies and exhausts air to the inside of the tubular member 1, causing the water level inside the tubular member 1 to fluctuate between a full water level and a low water level. As described above, the exhaust volume by the compressor 9 is set in stages so as to switch between a state in which the first electrode rod 21 is not submerged and a state in which the first electrode rod 21 is submerged. The supply volume by the compressor 9 is set in stages so as to switch between a state in which the fourth electrode rod 24 is submerged and a state in which the fourth electrode rod 24 is not submerged.
[0041] Therefore, as shown in Figure 4, when the compressor 9 exhausts air from inside the tubular member 1, the water level inside the tubular member 1 can rise above the water level outside the tubular member 1 to reach the full water level. Also, as shown in Figure 5, when the compressor 9 supplies air inside the tubular member 1, the water level inside the tubular member 1 can fall below the water level outside the tubular member 1 to reach the reduced water level.
[0042] Therefore, with the water level detection device 10 and the water level monitoring system 200 equipped therewith, it is possible to switch from a first state in which the water level inside the tubular member 1 is not at the full water level to a second state in which the water level inside the tubular member 1 is at the full water level, without supplying water to the water tank 100. When the first electrode rod 21 is functioning normally, in the first state the water level monitoring device 201 does not receive a full water level signal from the first electrode rod 21. Also, when the first electrode rod 21 is functioning normally, in the second state the water level monitoring device 201 receives a full water level signal from the first electrode rod 21 and outputs an alarm signal.
[0043] On the other hand, as shown in Figure 6, if the first electrode rod 21 has fallen out of the holding part 3, the water level monitoring device 201 will not receive a full water level signal from the first electrode rod 21 and will not output an alarm signal, even in the second state.
[0044] Therefore, by checking for the presence or absence of a full water level signal from the first electrode rod 21 to the water level monitoring device 201 or a signal from the water level monitoring device 201 to the first on-off valve 202 when switching from the first state to the second state, abnormalities such as the detachment of the first electrode rod 21 can be detected without visually inspecting the inside of the water tank.
[0045] According to the water level detection device 10 and the water level monitoring system 200 equipped therewith, the water level inside the tubular member 1 can be switched from a third state, where the water level inside the tubular member 1 is not at a reduced water level, to a fourth state, where the water level inside the tubular member 1 is at a reduced water level, without draining water from the water tank 100. When the fourth electrode rod 24 is functioning normally, in the third state, the water level monitoring device 201 does not receive a reduced water level signal from the fourth electrode rod 24. Also, when the fourth electrode rod 24 is functioning normally, in the fourth state, the water level monitoring device 201 receives a reduced water level signal from the fourth electrode rod 24 and outputs an alarm signal.
[0046] Furthermore, according to the water level monitoring system 200, it is possible to check whether the water level monitoring device 201 properly performs a predetermined alarm output operation when it is switched from the first state to the second state by the compressor 9, and when it is switched from the third state to the fourth state.
[0047] Preferably, the vertical movement of the water level inside the tubular member 1 accompanying the intake and exhaust of the compressor 9 is performed in stages, for example, so that each electrode rod 2 is alternately submerged and then not submerged. This allows for inspection of whether the other electrode rods 2, other than the first electrode rod 21 and the fourth electrode rod 24, are functioning correctly, similar to the first electrode rod 21 and the fourth electrode rod 24. Furthermore, it is possible to inspect whether the first on-off valve 202 performs its predetermined operation appropriately at each water level and whether the water level monitoring device 201 performs its predetermined alarm output operation appropriately.
[0048] <Effectiveness of water level detection devices, water level monitoring systems, and inspection methods for water level monitoring systems> The water level detection device 10 includes a tubular member 1 having an upper end portion 1A that is airtightly fixed to the upper wall 101 of the water tank 100 and a third opening 1B that opens into the water tank 100, a plurality of electrode rods 2 arranged inside the tubular member 1, and a first communication passage 4 and a second communication passage 5 that connect the inside of the tubular member 1 to the outside of the water tank 100 via a holding portion 3. Therefore, during normal operation as described above, by keeping the first communication passage 4 and the second communication passage 5 open, the water level inside the tubular member 1 becomes equal to the water level outside the tubular member 1 in the water tank 100. On the other hand, during maintenance and inspection as described above, the first communication passage 4 is closed and the second communication passage 5 is connected to the compressor 9, and the inside of the tubular member 1 is supplied with air and exhaust by the compressor 9, thereby allowing the water level inside the tubular member 1 to be raised and lowered without supplying or draining water to the water tank 100. As a result, the water level detection device 10 and the water level monitoring system 200 equipped with it can detect any detachment abnormalities in each of the multiple electrode rods 2 without supplying or draining water to the water tank 100 or visually inspecting the inside of the water tank 100.
[0049] Furthermore, the water level detection device 10 and the water level monitoring system 200 allow for the inspection of whether the first on-off valve 202 performs a predetermined operation and whether the water level monitoring device 201 performs a predetermined alarm output operation at each water level by raising and lowering the water level inside the tubular member 1 without supplying or draining water to or from the water tank 100.
[0050] Furthermore, in the water level detection device 10, the first connecting passage 4 and the second connecting passage 5 are each provided as through holes that penetrate the holding part 3. Such a water level detection device 10 can also be applied to existing water tanks 100 in which the first connecting passage 4 and the second connecting passage 5 are not formed in the upper wall 101 of the water tank 100.
[0051] Furthermore, in the water level detection device 10, the length between the upper end 1A of the tubular member 1 and the third opening 1B is equal to or greater than the length in the extending direction of the fifth electrode rod 25, which is the longest of the multiple electrode rods 2. As described above, since the lower end of the fifth electrode rod 25, which is a common electrode rod, is positioned below the reduced water level of the water tank 100, the third opening 1B of the first tubular member 1 is positioned below the reduced water level of the water tank 100. As a result, the water level detection device 10 can move the water level inside the tubular member 1 up and down between the full water level and the reduced water level of the water tank 100. With such a water level detection device 10 and water level monitoring system 200, it is possible to detect abnormalities in the detachment of the fifth electrode rod 25 and the shorter first electrode rods 21 to the fourth electrode rods 24, and to check whether the first on-off valve 202 performs a predetermined operation appropriately when the system switches from the third state to the fourth state, and whether the water level monitoring device 201 performs a predetermined alarm output operation appropriately.
[0052] Furthermore, in conventional water level detection devices, the electrode rods are immersed in the rippling water surface when water is supplied, requiring a timer circuit to prevent malfunctions due to the effects of waves. In contrast, with the water level detection device 10 and water level monitoring system 200, the water level rises smoothly inside the tubular member 1 even when water is supplied from the water inlet 102 into the water tank 100, and waves are less likely to form on the water surface, thus eliminating the need for a timer circuit.
[0053] <Variation> In the water level detection device 10, the first communication passage 4 and the second communication passage 5 only need to be formed in the upper wall 101 and in the portion of the holding part 3 that faces the inside of the tubular member 1. As shown in Figure 7, in the water level detection device 10, the first communication passage 4 and the second communication passage 5 may be through holes that penetrate a portion of the upper wall 101 that is located around the holding part 3 and faces the inside of the tubular member 1. In the water level detection device 10 shown in Figure 7, the upper end portion 1A of the tubular member 1 is directly fixed to the upper wall 101. The method of fixing the upper end portion 1A to the upper wall 101 is not particularly limited. The upper end portion 1A is fixed to the upper wall 101, for example, with an adhesive. Such a water level detection device 10 has the same effect as the water level detection device 10 shown in Figures 1 to 6.
[0054] Furthermore, as shown in Figure 8, even in the water level detection device 10 in which the upper end portion 1A of the tubular member 1 is directly fixed to the upper wall 101, the first connecting passage 4 and the second connecting passage 5 may be formed in the holding portion 3.
[0055] Each of the water level detection devices 10 described above only needs to be equipped with at least the second communication passage 5 of the first communication passage 4 and the second communication passage 5. Even in this case, if the second communication passage 5 is left open during normal operation, air can enter and exit between the upper space filled with air inside the tubular member 1 and the outside of the water receiving tank 100 when the water level inside the tubular member 1 moves up and down. Therefore, during normal operation, the water level inside the tubular member 1 can be at the same level as the water level inside the water receiving tank 100 and outside the tubular member 1.
[0056] On the other hand, if the water level detection device 10 shown in Figures 1 to 8 is equipped with a first connecting passage 4 and a second connecting passage 5, then by opening only the first connecting passage 4, air can enter and exit between the upper space filled with air inside the tubular member 1 and the outside of the water receiving tank 100. Therefore, during normal operation, only the first connecting passage 4 can be opened and the compressor 9 can be connected to the second connecting passage 5. In other words, with the water level detection device 10 shown in Figures 1 to 8, it is possible to keep the compressor 9 permanently installed.
[0057] While embodiments of this disclosure have been described above, it is possible to modify these embodiments in various ways. Furthermore, the scope of this disclosure is not limited to the embodiments described above. The scope of this disclosure is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]
[0058] 1 Tubular member, 1A Upper end, 1B Third opening, 2 Electrode rod, 3 Holding part, 4 First connecting passage, 5 Second connecting passage, 6 Terminal, 7 Case, 8 Closing member, 9 Compressor, 10 Water level detection device, 21 First electrode rod, 22 Electrode rod for detecting low water level, 100 Water receiving tank, 101 Upper wall, 101A First opening, 101B Second opening, 102 Water inlet, 103 Drain outlet, 120 Cover, 200 Water level monitoring system, 201 Water level monitoring device, 202 First on / off valve.
Claims
1. A water level detection device for detecting the water level in a water tank, A tubular member placed inside the water tank, A plurality of electrode rods are arranged inside the tubular member within the water receiving tank, The system includes a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water receiving tank, The tubular member has an upper end that is airtightly fixed to either the upper wall or the holding part of the water tank, and an opening that opens into the water tank. The upper wall and the portion of the holding part facing the inside of the tubular member further provide at least one communication passage that connects the inside of the tubular member to the outside of the water receiving tank, The tubular member is provided such that water or air inside the water tank can enter and exit the inside of the tubular member and the outside of the tubular member only through the opening. A water level detection device further comprising a pump that draws air into the tubular member and exhausts air from the inside of the tubular member via at least one connecting passage.
2. The water level detection device according to claim 1, wherein the at least one communication passage is a through hole that penetrates the holding portion.
3. A water level detection device for detecting the water level in a water tank, A tubular member placed inside the water tank, A plurality of electrode rods are arranged inside the tubular member within the water receiving tank, The system includes a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water receiving tank, The tubular member has an upper end that is airtightly fixed to either the upper wall or the holding part of the water tank, and an opening that opens into the water tank. The upper wall and the portion of the holding part facing the inside of the tubular member further provide at least one communication passage that connects the inside of the tubular member to the outside of the water receiving tank, A water level detection device in which the at least one communication passage is a through hole that penetrates the upper wall located around the holding portion.
4. A water level detection device for detecting the water level in a water tank, A tubular member placed inside the water tank, A plurality of electrode rods are arranged inside the tubular member within the water receiving tank, The system includes a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water receiving tank, The tubular member has an upper end that is airtightly fixed to either the upper wall or the holding part of the water tank, and an opening that opens into the water tank. The upper wall and the portion of the holding part facing the inside of the tubular member further provide at least one communication passage that connects the inside of the tubular member to the outside of the water receiving tank, The aforementioned at least one connecting passage includes a first connecting passage and a second connecting passage, A water level detection device further comprising an on / off valve for opening and closing the first connecting passage.
5. The water level detection device according to claim 4, further comprising a pump connected to the second communication passage for drawing air into the tubular member or exhausting air from the tubular member via the second communication passage.
6. The water level detection device according to any one of claims 1 to 5, wherein the length between the upper end of the tubular member and the opening is equal to or greater than the length in the extending direction of the longest electrode rod among the plurality of electrode rods.
7. The water level detection device according to any one of claims 1 to 5, wherein the tubular member is transparent.
8. A water level detection device according to any one of claims 1 to 5, A water level monitoring system comprising a water level monitoring device that supplies and drains water to the water tank according to the water level in the water tank detected by the water level detection device.
9. A method for inspecting a water level monitoring system comprising a water level detection device for detecting the water level in a water tank and a water level monitoring device for supplying and draining water to the water tank according to the water level in the water tank detected by the water level detection device, The water level detection device is A tubular member placed inside the water tank, A plurality of electrode rods are arranged inside the tubular member within the water receiving tank, The system includes a holding part that holds the plurality of electrode rods and is fixed to the upper wall of the water receiving tank, The tubular member has an upper end that is airtightly fixed to either the upper wall or the holding part of the water tank, and an opening that opens into the water tank. The water level detection device further includes a communication passage that connects the inside of the tubular member to the outside of the water tank via the upper wall and the portion of the holding part that faces the inside of the tubular member, A method for inspecting a water level monitoring system, comprising the steps of supplying air into the tubular member or exhausting air from the tubular member via the communication passage to change the water level inside the tubular member and confirming the response of the water level monitoring device.