JP2012251839A - Electrode type level detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode type level detection device that can securely detect the liquid level of even a liquid with low electric conductivity, and is easily applicable to even an existing electrode type level detection device.SOLUTION: There is provided an electrode type level detection device 1 which detects the liquid level in a drain water tank 5, the electrode type level detection device including an electrode type level detector 11 which detects the liquid level, a detection liquid 14 which is different from the liquid in the drain water tank 5 and has higher electric conductivity than the liquid in the drain water tank 5, and a cylindrical body 13 which is sectioned from the liquid in the drain water tank 5, and holds the detection liquid 14 in a predetermined place in the drain water tank 5. The cylindrical body 13 is bottomless, the detection liquid 14 in the cylindrical body 13 moves up and down integrally with the drain 10 in the drain water tank 5, and the electrode type level detector 11 detects the liquid level of the detection liquid 14 to detect the liquid level in the drain water tank 5.

Description

  The present invention relates to an electrode type level detection apparatus that is installed in a tank such as a drain tank and detects a liquid level in the tank. In the present invention, the tank includes a container and a device for storing the liquid, the liquid includes water, and the drainage includes drainage. The electrical conductivity is often written as conductivity, conductivity, and electrical conductivity, but is referred to as conductivity in this specification.

  In the power plant, wastewater generated by the operation of the unit is once collected in a drainage tank and then sent to a wastewater treatment device for processing. Water supply from the drainage tank to the wastewater treatment apparatus is performed via a drainage pump, and the drainage pump is activated and stopped based on a signal from a level switch provided in the drainage tank. When the level switch detects the high water level of the drain tank, the drain pump is activated to start water supply, and when the water level of the drain tank drops to a predetermined water level (low water level) due to the water supply, the drain pump is stopped. Thereby, the drainage tank can be maintained at a predetermined water level.

  Examples of the level switch for detecting the water level in the drainage tank include an electrode type level switch and a displacer type level switch. The electrode type level switch is one of the level switches that are often used because of its simple structure and low cost. The electrode type level switch detects the water level when the electrode is in contact with the drainage, and an electric circuit is formed between the electrodes and is energized. Therefore, when the electrolyte contained in the drainage is small, for example, the conductivity is as low as 5 μS / cm or less. In conductivity drainage, the water level cannot be detected even if the electrode contacts the drainage. It occurs when a large amount of pure water drainage is discharged, and the same indication has been made in other devices (for example, see Patent Document 1 and Patent Document 2).

Japanese Utility Model Publication No. 7-12703 JP 2010-8379 A

  In the device described in Patent Literature 1, if pure water with extremely low conductivity is used for boiler water supply, the water level cannot be controlled with an electrode-type water level detector. A water level detector is provided, and two water level detectors are selectively used according to the conductivity. Although the idea of patent document 1 can be applied to a drainage tank, in the case of a drainage tank, only a non-electrode type water level detector can be used to detect the water level.

  In the invention described in Patent Document 2, a plate-like conductive member having a large cross-sectional area is attached to the tip of the electrode rod, and when the conductive member is immersed in water, the same state is created as if the electrode rod was deeply immersed in water. This improves the detection accuracy of the liquid level. In the case of the invention described in Patent Document 2, it is necessary to prevent the conductive member from coming into contact with other electrode rods. For this purpose, it is necessary to increase the distance between adjacent electrode rods. In the existing electrode type level switch, since the position of the electrode rod is fixed, it is not easy to apply this method. Further, depending on the properties of the drainage, it is necessary to increase the area (bottom area) of the conductive member, and a large installation space is required.

  An object of the present invention is to provide an electrode type level detection device that can reliably detect a liquid level even with a low conductivity liquid and can be easily applied to an existing electrode type level detection device. That is.

  The present invention is an electrode type level detection device for detecting a liquid level in a tank, and has an electric conductivity level compared to an electrode type level detector for detecting a liquid level and a liquid in a tank different from the liquid in the tank. And a holding means for holding the detection liquid at a predetermined location in the tank, and the detection liquid moves up and down integrally with the liquid in the tank. The electrode type level detector detects the liquid level of the detection liquid by the electrode type level detector and detects the liquid level in the tank.

  In the electrode type level detection apparatus of the present invention, the holding means is a bottomless cylinder that surrounds the electrode of the electrode type level detector and is partly immersed in the liquid in the tank. Is provided with a water-permeable container filled with salt at a predetermined height, and the detection liquid comes into contact with the salt when the liquid in the tank rises above a predetermined height and the salt is liquid. It is formed by being dissolved in.

  In the electrode type level detection apparatus of the present invention, the detection liquid is formed by supplying a liquid having high conductivity into the cylinder instead of the salt.

  In the electrode type level detection apparatus of the present invention, the tank is a tank for storing waste liquid to be processed by the drainage processing apparatus, and the detection liquid can be processed by the drainage processing apparatus together with the drainage liquid. It is characterized by.

  In the electrode type level detection apparatus of the present invention, the holding means is a container having an open top with a float attached, the detection liquid is filled in the container, and the container floats in the tank. It moves up and down integrally with the liquid inside.

  The electrode type level detection device of the present invention detects the liquid level in the tank by detecting the liquid level of the detection liquid having a higher conductivity than the liquid in the tank that moves up and down integrally with the liquid in the tank. Therefore, even if the electrical conductivity of the liquid in the tank is low, the liquid level in the tank can be reliably detected. The detection liquid is separated from the liquid in the tank through the holding means and is held at a predetermined position in the tank, and it is necessary to modify the electrode type level detector when introducing the electrode type level detection apparatus of the present invention. Therefore, the present invention can be easily applied to an existing electrode type level detection device.

  Further, according to the electrode type level detection device of the present invention, a bottomless cylinder is installed in the tank, and a water-permeable container filled with salt at a predetermined height in the cylinder is installed, and the liquid in the tank is Since the detection liquid may be formed by rising above a predetermined height and coming into contact with the salt, it can be easily applied to an existing electrode type level detection device. Since salt is not in constant contact with the liquid, the consumption of salt is low and the running cost is low.

  Further, according to the electrode type level detection apparatus of the present invention, the detection liquid may be formed by supplying a liquid having a high conductivity, for example, an electrolyte solution, into the cylindrical body. Can be easily applied. Since the cylindrical body only needs to be large enough to surround the electrode, a small volume of liquid having a small conductivity and a high electrical conductivity to be added is sufficient. For this reason, the running cost is small.

  Further, in the electrode type level detection device of the present invention, the detection liquid is only separated from the liquid by a cylindrical body without a bottom, so that part of the detection liquid is discharged out of the cylinder along with the vertical movement of the liquid level. However, if the detection liquid is a liquid that can be processed by the drainage processing apparatus together with the drainage liquid, no special treatment is required. For this reason, the electrode type level detection apparatus of this invention can be used conveniently as a liquid level detection apparatus of the tank which stores a drainage liquid.

  Further, according to the electrode type level detection apparatus of the present invention, the detection liquid is filled in the container with the float, and this is moved up and down integrally with the liquid in the floating tank in the tank, and the detection liquid is detected by the electrode type level detector. Since the liquid level in the tank may be detected by detecting the liquid level, the liquid level in the tank can be reliably detected even when the conductivity of the liquid in the tank is low. Moreover, the electrode type level detection apparatus of the present invention does not require modification of the electrode type level detector and can be easily applied to an existing electrode type level detection apparatus.

It is a figure showing the schematic structure of electrode type level detector 1 as a 1st embodiment of the present invention. It is a figure which shows schematic structure of the electrode-type level detection apparatus 2 as 2nd Embodiment of this invention. It is a figure which shows schematic structure of the electrode-type level detection apparatus 3 as 3rd Embodiment of this invention.

  FIG. 1 is a diagram showing a schematic configuration of an electrode type level detection apparatus 1 as a first embodiment of the present invention. Hereinafter, the configuration and action of the electrode type level detection device 1 are to receive and store wastewater with low conductivity, and send the wastewater to a wastewater treatment device (not shown) via a drainage pump (not shown) to a predetermined water level. The case where it installs and uses for the drainage tank 5 hold | maintained in this is demonstrated as an example. The drainage with low conductivity is drainage with low conductivity and no electric circuit is formed between the electrodes even when the electrodes of the electrode type level detector are immersed.

  The electrode type level detection device 1 is a device that detects the water level of the drainage tank 5, and the electrode type level detector 11 that detects the water level and the drainage 10 are partitioned into the drainage tank 5. And a salt 13 filled in a water-permeable bag 15 for making the detection liquid 14 having a higher conductivity than the drainage 10 in the cylinder 13.

  The electrode type level detector 11 is a level meter that detects the water level in the drainage tank 5, directly the water level in the cylinder 13, and has three electrodes 23, 25, 27 having different lengths in the main body 21. Is installed. The right electrode 23 is at a position where the tip 29 is further lower than the low water level (L) of the drain tank 5 and is always immersed in the detection liquid 14. The center electrode 25 is an electrode for detecting the low water level (L) of the drain tank 5, and the tip 31 is set at the low water level (L) of the drain tank 5. The left electrode 27 is an electrode for detecting the water level height (H) of the drainage tank, and the tip 33 is set at the position of the water level height (L) of the drainage tank 5.

  When the electrode 23 and the electrode 25 are both immersed in the detection liquid 14, the electrode type level detector 11 forms an electric circuit and detects the low water level (L) of the drainage tank 5. Further, when the electrode 27 is immersed in the detection liquid 14, an electric circuit is formed between the electrode 23 and the electrode 27, and the water level height (H) of the drainage tank 5 is detected. The detected water level is sent to a control device (not shown) that controls the drainage pump. Such an electrode type level detector 11 is the same as a known electrode type level detector conventionally used.

  The cylinder 13 is a member for partitioning the drainage tank 5 from the drainage 10 and holding a liquid having a higher conductivity than the drainage 10 and the detection liquid 14 in the cylinder 13. The cylindrical body 13 is a cylindrical cylinder having an open bottom surface and a ceiling surface. The cylindrical body 13 communicates with the inside and outside of the cylindrical body 13 and is installed so as to surround the three electrodes 23, 25, and 27. Further, a water-permeable bag 15 filled with the salt 17 is hung inside the cylinder 13. The lower end 35 of the cylinder 13 is a position lower than the tip end portion 29 of the electrode 23, and the upper end 37 is a position higher than the water level height (H) of the drainage tank 5. In the case of the drainage tank 5, the water surface may wave due to the inflowing drainage 10, but by providing the cylindrical body 13, the water level can be detected in a state where the influence of the wave is eliminated.

  The diameter of the cylindrical body 13 is not particularly limited as long as it surrounds the three electrodes 23, 25, and 27 and has a size that prevents the water-permeable bag 15 filled with the salt 17 from contacting the electrodes 23, 25, and 27. The smaller one is preferable. The installation space is reduced by reducing the diameter of the cylinder 13, and the volume in the cylinder 13 is further reduced, so that the amount of salt required to increase the conductivity of the drainage in the cylinder 13 is reduced. Here, the tubular body 13 is used to suspend the water-permeable bag 15 filled with the salt 17. However, if the bag 15 is not suspended, basically no force is applied to the tubular body 13, so the thickness is small. Also good. The material is not limited to a specific material as long as it is a material that does not corrode with the drainage 10 and the detection liquid 14, and plastic or metal material can be used. If a transparent plastic material is used, the state inside the cylinder 13, particularly the state of the bag 15 filled with the salt 17, can be visually recognized from the outside.

  The detection liquid 14 is a liquid used for detecting the water level in the drain tank 5, and the electrode type level detector 11 detects this liquid level (water level). The detection liquid 14 is formed by the drainage 10 in the cylinder 13 coming into contact with the salt 17, and the salt 17 is dissolved in the drainage 10 in the cylinder 13, and the conductivity is higher than that of the drainage 10.

  The salt 17 is dissolved in the drainage 10 by coming into contact with the drainage 10 and is used to increase the conductivity of the drainage in the cylinder 13. The salt 17 is filled in the water-permeable bag 15. The tip 39 is attached so as to be between the low water level (L) and the high water level (H) of the drainage tank 5. The electrical conductivity of the drainage in the cylinder 13 is not limited as long as it has an electrical conductivity that can reliably form an electric path between the electrodes 23, 25, and 27 when the electrodes 23, 25, and 27 come into contact with the drainage (detection liquid 14). There is no need to increase the degree. By installing the bag 15 filled with the salt 17 as described above, it is possible to prevent the salt from being in constant contact with the waste water in the cylindrical body 13 and to suppress the amount of the salt 17 used.

  The salt 17 can be used without being limited to a specific salt as long as it can be dissolved in the waste water 10 to increase the conductivity, but is preferably one that can be easily post-treated. Since the inside and outside of the cylindrical body 13 communicate with each other, the drainage 10 enters the cylindrical body 13 as the water level of the drain tank 5 moves up and down, and conversely, the detection liquid 14 in the cylindrical body 13 moves outside the cylindrical body 13. To be discharged. Since the detection liquid 14 discharged out of the cylindrical body 13 is combined with the waste water 10 and finally processed by the waste water treatment device, the detection liquid 14 is the same as the waste water 10 not containing the salt 17. It is preferable that it can be processed by a processing method. Furthermore, the salt 17 is more preferable if it is safe, easily available, and inexpensive. An example of such a salt is sodium chloride.

  The bag 15 is a water-permeable bag and has a function of holding the salt 17 to be filled and bringing the filled salt 17 into contact with the drainage 10 when the water level rises. The water permeation performance affects the amount of salt 17 dissolved and affects the conductivity of the detection liquid 14, and therefore is determined appropriately in consideration of this point. The bag 15 is filled with salt 17 inside, and when it comes into contact with the drainage 10, the weight of the drainage 10 adhering to the salt 17 is added in addition to the salt 17, so that it must be strong enough to withstand this. As such a bag 15, a cloth-type bag such as a woven fabric or a non-woven fabric having resistance to the drainage 10 and the salt 17 can be used. Instead of the bag, a water permeable container, for example, a container having a mesh part at the bottom, a container formed entirely by a mesh, or the like may be used. The bag 15 filled with the salt 17 is suspended by a hook 41 hooked on the cylinder 13. The bag 15 may be attached by other methods as long as the tip 39 can be attached between the low water level (L) and the high water level (H) of the drainage tank 5. Is preferably easy.

  The operation of the electrode type level detector 1 will be described. At the time of start-up, the current water level is between the low water level (L) and the high water level (H), and the bag 17 is not in contact with the drainage 10. In this case, the liquid in the cylinder 13 and the liquid outside the cylinder 13 are the same low conductivity drainage, and the electrode 25 for detecting the low water level (L) is immersed in the drainage 10. Therefore, the electric circuit is not formed between the electrode 25 and the electrode 23, and the electrode type level detector 11 cannot detect that the water level is a water level lower than the water level (L) or higher. For this reason, the drainage 10 flows into the drainage tank 5 and the water level rises. When the water level rises and the drainage 10 comes into contact with the bag 15, the salt 17 dissolves and the conductivity of the drainage 10 in the cylinder 13 increases. At this point, the detection liquid 14 is formed. When the conductivity of the drainage water 10 in the cylinder 13 is increased, an electric circuit is formed between the electrode 25 and the electrode 23, and the electrode type level detector 11 indicates that the water level is a water level lower than the water level (L). Detect and send signal to drain pump controller.

  Since the drainage pump is controlled so as not to be activated unless a high water level (H) signal is input, the water level in the drainage tank 5 continues to rise. When the water level in the drainage tank 5 rises, new drainage 10 flows into the cylinder 13 from the bottom. However, in the cylinder 13, the drainage 10 containing the detection liquid 14 continues to come into contact with the salt 17, so the cylinder 13 The conductivity remains high. When the water level further rises and the detection liquid 14 comes into contact with the electrode 27, an electric circuit is formed between the electrode 27 and the electrode 23. The electrode type level detector 11 detects the high water level (H) and sends the signal to the drainage pump. Send to controller. As a result, the drainage pump is activated, and the wastewater 10 in the drainage tank 5 is sent to the wastewater treatment device.

  When water supply is started by the drain pump, the water level in the drain tank 5 is lowered and the water level in the cylinder 13 is also lowered at the same time. When the water level falls below the tip 33 of the electrode 27, the electric circuit between the electrode 27 and the electrode 23 is opened, but the drain pump does not discharge the drain until the electrode type level detector 11 detects a low water level (L). continue. When the water level falls below the bag 15, the dissolution of the salt 17 stops, and when the water level falls below the tip 31 of the electrode 25, the electrical circuit between the electrode 25 and the electrode 23 is opened, and the electrode type level detector 11 detects a low water level (L) and sends a signal to the drain pump controller. This stops the drainage pump.

  When the water level rises again, new drainage 10 flows into the cylinder 13, but the conductivity of the cylinder 13 is higher than that of the drainage 10. Since the cylindrical body 13 is installed so that the lower end 35 is positioned lower than the tip portion 29 of the electrode 23, the drainage (detection liquid 14) in the cylindrical body 13 has a low water level in the drainage tank 5. This is because even if it becomes (L), a part remains as it is without being discharged out of the cylinder 13. For this reason, the electrical conductivity in the cylindrical body 13 is maintained higher than the electrical conductivity of the drainage 10 after the detection liquid 14 is once formed in the cylindrical body 13 except at the time of startup. By the above operation, the water level in the drainage tank 5 is controlled between the low water level (L) and the high water level (H).

  FIG. 2 is a diagram showing a schematic configuration of an electrode type level detection apparatus 2 as a second embodiment of the present invention. The same components as those of the electrode type level detector 1 shown in FIG. Similarly to the electrode type level detection device 1 shown in the first embodiment, the electrode type level detection device 2 detects the water level of the drainage (detection liquid 14) in which the electrode type level detector 11 has increased conductivity in the cylindrical body 13. By detecting, the water level of the drain tank 5 is detected. In the first embodiment, when the drainage 10 rises to a predetermined water level or higher, the drainage 10 comes into contact with the salt 17 to increase the conductivity of the drainage in the cylindrical body 13. The conductivity of the drainage 10 is increased using the solution.

  The electrode type level detection device 2 includes an electrolyte addition device 51 that adds an electrolyte solution into the cylindrical body 13. The electrolyte addition device 51 includes a tank 55 that stores the electrolyte solution 53 and a supply pipe 57 that supplies the electrolyte solution 53 stored in the tank 55 into the cylinder 13, and the electrolyte solution 53 in the tank 55 is tubed by a head difference. It is dropped into the body 13. A valve 59 is provided in the middle of the supply pipe 57, whereby the dripping amount can be adjusted.

  The dropping amount of the electrolyte solution 53 needs to be an amount such that the conductivity of the waste water in the cylinder 13 is such that the electrode level detector 11 can detect the water level reliably. It may be set as appropriate in consideration of the size of the liquid, the change in water level, the concentration of the electrolyte solution, and the like. Since the waste water (detection liquid 14) in the cylinder 13 is only partially replaced even if the water level moves up and down, the amount of electrolyte used is small. Basically, the dropping amount of the electrolyte solution 53 is increased as the change in the diameter and the water level of the cylinder 13 is increased, and is decreased as the concentration of the electrolyte solution 53 is increased. The electrical conductivity of the waste water in the cylindrical body 13 may be an electrical conductivity that can reliably detect the water level with the electrode type level detector 11, and it is necessary to make it higher than necessary from the viewpoint of suppressing the waste of chemicals. Absent.

  In the present embodiment, since the electrolyte solution 53 is dropped using the head difference, the electrolyte solution 53 is continuously supplied. If the supply amount is made small, the droplets 61 are supplied at a predetermined interval. In this case, however, the supply is continuous when viewed from a long span. Instead of the supply using the head difference, the electrolyte solution 53 may be supplied using a fixed supply pump. If a metering pump is used, intermittent supply is possible.

  The electrolyte solution 53 can be used without being limited to a specific electrolyte solution as long as it dissolves in the waste water 10 to increase the conductivity and does not corrode the electrodes 23, 25, 27, etc. Like the detection liquid 14 of the embodiment, those that can be easily post-processed are preferable. Since the wastewater in which the electrolyte solution 53 is dissolved is finally treated by a wastewater treatment apparatus, it is preferable that the wastewater can be treated by the same treatment method as the wastewater not containing the electrolyte solution 53. Furthermore, it is more preferable if it is safe, easily available, and inexpensive. In particular, chemicals used in wastewater treatment equipment are more preferable in terms of treatment and availability. Examples of the electrolyte solution 53 include an aqueous sodium hydroxide solution, sulfuric acid, and hydrochloric acid. In addition, when using sodium hydroxide aqueous solution etc., it is desirable to use the thing below the density | concentration designated as a deleterious substance poison.

  Since the electrolyte solution 53 is added to increase the conductivity of the wastewater 10, wastewater or drainage with high conductivity may be used instead of the electrolyte solution 53. This highly conductive wastewater and drainage is preferable because it can be easily obtained if it is drainage and drainage discharged from the plant in which the drainage tank 5 is installed. Further, as in the case of the electrolyte solution 53, since it is finally treated by the waste water treatment device, it is preferable that it can be treated by the same treatment method as waste water having high conductivity and waste water not containing waste liquid. Use of such highly conductive drainage and drainage eliminates the need for chemical charges.

  The method of using the electrode type level detection device 2 is the same as that of the electrode type level detection device 1 of the first embodiment, and the water level of the drainage 10 can be reliably detected even when the conductivity of the drainage 10 is low. The operational effects are basically the same as those of the electrode type level detection apparatus 1. The apparatus configuration is also very simple, and it is not necessary to modify the electrode type level detector 11, so that it can be easily applied to an electrode type level detection apparatus using the existing electrode type level detector 11. Further, as in the electrode type level detector 1, only the inside of the cylinder 13 is used as the detection liquid 14, so that the addition amount of the electrolyte solution 53 is small, and the operation cost is low.

  FIG. 3 is a diagram showing a schematic configuration of an electrode type level detector 3 as a third embodiment of the present invention. The same components as those of the electrode type level detector 1 shown in FIG. Similarly to the electrode type level detection devices 1 and 2, the electrode type level detection device 3 does not directly detect the water level of the waste water 10 in the drain tank 5 by the electrode type level detector 11, but uses a liquid with high conductivity. It is used to detect the water level in the drain tank 5. In the electrode type level detectors 1 and 2, a cylinder 13 is installed in the drainage tank 5, and the water level in the drainage tank 5 is detected by increasing the conductivity of the drainage in the cylinder 13 and detecting the level of the drainage. However, the electrode type level detection device 3 floats the container 71 containing the high conductivity liquid (detection liquid 14) on the drainage tank 5, and detects the liquid level of the detection liquid 14, thereby Detect water level.

  In addition to the electrode type level detector 11, the electrode type level detector 3 includes a container 71 filled with the detection liquid 14, and a guide 73 for moving the container 71 up and down at the same position. The container 71 is a cylindrical container having a bottom and an open top, and is large enough to receive the three electrodes 23, 25, 27 of the electrode type level detector 11. The depth of the container 71 is such that the tip portion 29 of the electrode 23 does not contact the bottom even when the water level of the drainage tank 5 is raised most. The size of the container 71 does not need to be larger than necessary as long as the above conditions are satisfied, and the shape is not limited to the cylindrical container.

  A float 75 is attached to the upper outer peripheral portion of the container 71, and the container 71 filled with the detection liquid 14 can float on the drainage 10. The float 75 is attached so that the liquid level 18 of the detection liquid 14 filled in the container 71 is at the same height as the liquid level 12 of the drainage 10. If the liquid level 18 of the detection liquid 14 filled in the container 71 does not become the same height as the liquid level 12 of the drainage 10 with only the float 75, a balance weight (not shown) is attached to the container 71. It is preferable that the liquid level 18 of the detection liquid 14 filled therein is at the same height as the liquid level 12 of the drainage 10. The material of the container 71 is not limited to a specific material as long as it is a material that does not corrode with the drainage 10 and the detection liquid 14, and plastic or metal material can be used. It is preferable to use a transparent plastic material because the liquid level 18 of the detection liquid 14 can be visually recognized from the outside.

  The conductivity of the detection liquid 14 has such an electrical conductivity that an electric circuit is reliably formed when the electrodes 23, 25, 27 are immersed. As long as it has such conductivity and does not corrode the electrodes 23, 25, 27, etc., it can be used without being limited to a specific liquid. The detection liquid 14 is preferably safe, easily available, and inexpensive. In particular, if the detection liquid 14 can be prepared using a chemical used in a wastewater treatment apparatus, it is more preferable in terms of processing and availability. Moreover, if it can process with a waste water treatment equipment, post-processing is easy and it is more preferable. Examples of the detection solution 14 include an aqueous sodium chloride solution, an aqueous sodium hydroxide solution, an aqueous hydrochloric acid solution, and an aqueous sulfuric acid solution. Moreover, you may use the waste_water | drain with high electrical conductivity discharged | emitted from a plant, and drainage liquid.

  The guide 73 is for stably moving the container 71 filled with the detection liquid 14 directly below the electrodes 23, 25, 27 so that the electrodes 23, 25, 27 are surely immersed in the detection liquid 14. It is fixed in the drain tank 5. The guide 73 is formed of a cylindrical pipe whose upper and bottom surfaces are open, and has a size that allows a slight gap between the guide 73 and the float 75 attached around the container 71 when the container 71 is enclosed. Since the guide 73 is for stably moving the container 71 up and down directly under the electrodes 23, 25 and 27, it is uneconomical to make it larger than necessary if it has such a function.

  If the container 71 filled with the detection liquid 14 can move up and down at the same position, the guide 73 is not necessarily provided. However, in the case of the drainage tank 5, it is preferable to install the guide 73 because a force may be applied so that the container 71 is swept away by the flow of the wastewater 10 flowing in or the waves generated by the drainage 10 flowing in. Further, the guide 73 is preferably provided so as to surround the entire circumference of the container 71 in order to eliminate the influence of waves. The material of the guide 73 is not limited to a specific material as long as it does not corrode with the drainage 10, but it is preferable to use a transparent plastic material because the movement of the container 73 can be visually recognized from the outside.

  A usage example of the electrode type level detection device 3 will be described. The container 71 filled with the detection liquid 14 is put in the guide 73 and floated in the drain tank 5. The electrode type level detector 11 is installed so that the three electrodes 23, 25, 27 are located in the container 71. The liquid level of the detection liquid 14 in the container 71 is the same as the water level of the drain tank 5, and the container 71 moves up and down together with the drainage 10 of the drain tank 5. By detecting the liquid level of the detection liquid 14, the water level of the drainage tank 10 can be detected.

  Similarly to the electrode type level detection apparatuses 1 and 2 shown in the first and second embodiments, the electrode type level detection apparatus 3 shown in the third embodiment directly detects the liquid level of the detection liquid 14. Since the water level of the drainage tank 10 is detected, the water level can be reliably detected even for wastewater having a low electrical conductivity, such as pure water drainage.

  The electrode type level detection apparatus according to the present invention is not limited to the above embodiment. In the said embodiment, although the waste_water | drain 10 of the drain tank 5 was demonstrated as an example, it cannot be overemphasized that it may replace with the waste_water | drain 10 and may be a drainage liquid. Moreover, although the example which detects the water level of two points, water level low and water level high, was shown in the said embodiment, the water level to detect is not limited to two points. In the electrode type level detection device 3 of the third embodiment, the liquid level of the detection liquid 14 in the container 71 and the water level of the drainage 10 are the same. However, the detection in the container 71 is performed due to circumstances such as the structure of the drainage tank 5. When the liquid level of the liquid 14 and the water level of the drainage 10 cannot be made the same, the water level of the drainage tank 5 can be detected by determining the height of the electrodes 25 and 27 in consideration of the difference in advance.

1, 2, 3 Electrode type level detector 5 Drain tank 10 Drain 11 Electrode level detector 12 Drain liquid level 13 Cylinder 14 Detected liquid 15 Bag 17 Salt 18 Detected liquid level 23, 25, 27 Electrode 51 Electrolyte Addition device 71 Container 73 Guide 75 Floating

Claims (5)

An electrode type level detection device for detecting the liquid level in the tank,
An electrode type level detector for detecting the liquid level;
A detection liquid having a higher conductivity than the liquid in the tank different from the liquid in the tank,
A holding means for partitioning the liquid in the tank and holding the detection liquid in a predetermined place in the tank;
With
The detection liquid moves up and down integrally with the liquid in the tank, and detects the liquid level in the tank by detecting the liquid level of the detection liquid with the electrode type level detector. apparatus. The holding means is a bottomless cylinder that surrounds the electrode of the electrode type level detector and is partly immersed in the liquid in the tank. The cylinder is filled with salt at a predetermined height. A water permeable container is installed,
2. The electrode type level according to claim 1, wherein the detection liquid is formed by the liquid in the tank rising above a predetermined height to come into contact with the salt, and the salt is dissolved in the liquid. Detection device.   The electrode type level detection apparatus according to claim 2, wherein the detection liquid is formed by supplying a liquid having high conductivity into the cylindrical body instead of the salt. The tank is a tank for storing waste liquid to be processed by a drain processing apparatus,
The electrode type level detection apparatus according to claim 1, wherein the detection liquid can be processed by the drainage processing apparatus together with drainage. The holding means is a container having an open top with a float attached,
The electrode type level detection apparatus according to claim 1, wherein the detection liquid is filled in the container, and the container floats in the tank and moves up and down integrally with the liquid in the tank.

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