JP5136830B2 - Cooling tower makeup water quality control device - Google Patents

Description

  The present invention relates to a water quality adjusting device for cooling tower make-up water, and more particularly to a water quality adjusting device for cooling tower make-up water that suppresses the hardness of circulating water circulating in the cooling tower.

  Conventionally, in air conditioning equipment such as commercial buildings and various factories, water treatment systems that circulate cooling water and cool a device to be cooled such as a heat exchanger have been widely adopted.

  In this type of water treatment system, since the cooling water is circulated, the circulating water is concentrated by evaporation of water, and the dissolved water and nutrients are contained in the circulating water at a high concentration. As a result, the quality of the circulating water deteriorates, algae and slime are generated, and there is a possibility that water permeability deteriorates and cooling capacity decreases. In addition, Legionella bacteria are propagated due to the slime and the like, and the propagated Legionella bacteria are likely to be entrained in the evaporated water and scattered in the atmosphere. Furthermore, scales may accumulate due to the concentration of hardness components and silica and adhere to the apparatus to be cooled, leading to a decrease in thermal efficiency.

  And it is effective to use soft water for circulating water to prevent the above-mentioned generation of algae, slime and scale.

  However, in this soft water, hardness components such as calcium ions are generally removed by the water softener, and therefore, the soft water is substantially free of the hardness component, so that the pipe is compared with the hard water containing the hardness component. There is a drawback that corrosion is likely to occur.

  As an index for evaluating the corrosiveness of water in a piping system, a Langeria index L represented by the following formula (1) is conventionally known.

L = pH-pHs (1)
Here, pH has shown the measured pH value of water. Further, pHs indicates a pH value in an equilibrium state where calcium carbonate does not dissolve or precipitate in water, that is, a theoretical pH value, and this pHs is expressed by Equation (2).

pHs = (9.3 + A + B) − (C + D) (2)
Here, A is a value determined by the concentration of the evaporation residue, B is a value determined by the water temperature, C is a value determined by the calcium hardness, and D is a value determined by the total alkalinity.

  It is considered that pipe corrosion can be suppressed by forming a calcium carbonate film on the contact surface between water and metal, that is, on the inner peripheral surface of the pipe. Therefore, in the formula (1), when the Langeria index L is a negative value, that is, when the theoretical pH value, pHs, is larger than the actually measured pH value, as is clear from the formula (2), the numerical value C determined by the calcium hardness. Is relatively small, which increases the corrosivity of water. On the other hand, when the Langeria index L is a positive value, that is, when the pH, which is the theoretical pH value, is smaller than the actually measured pH value, the numerical value C determined by the calcium hardness is relatively large and water corrosivity can be suppressed. it is conceivable that.

  That is, when the Langelia index L is a negative value with “0” as a boundary, the corrosiveness of water is increased, and when the Langerian index L is positive, the corrosiveness of water is suppressed. Therefore, in order to suppress the pipe corrosion, it is desirable that the Langeria index L is at least “0” or a positive value. For that purpose, it is desirable to include hard water containing calcium ions in the circulating water.

  And in patent document 1, while supplying a part of softened water obtained by processing a part of raw | natural water with a cation exchange resin to a cooling water system in an open circulation cooling water system, another part of softened water is used. There has been proposed a method for treating cooling water in which the salt solution prepared above is electrolyzed to produce free residual chlorine, and this free residual chlorine-containing water is added to the cooling water system.

  In this Patent Document 1, a mixed water of hard water (raw water) having a hardness component and soft water is supplied to a cooling tower as make-up water, thereby preventing slime and scale from being generated and trying to suppress metal corrosion. Yes.

JP 2004-121969 A

  However, in patent document 1, since the mixed water of hard water and soft water is replenished to the cooling tower, there is a possibility that hard water more than necessary may be replenished to the cooling tower.

  That is, in order to suppress the generation of slime and scale and ensure good water quality, it is preferable to use soft water as much as possible as the circulating water, and if hard water is replenished as necessary from the viewpoint of preventing corrosion of the piping It is enough.

  Further, in Patent Document 1, the water quality is stabilized with a hardness in an appropriate range and the cooling tower is operated. However, since soft water is supplied to the cooling tower together with hard water immediately after the operation is started, the hardness reaches an appropriate range. Takes a certain amount of time. In other words, it takes a relatively long time to achieve an operation state with stable water quality.

  Moreover, in Patent Document 1, since the mixed water of soft water and hard water is replenished, the concentration is easy to proceed. Therefore, it is necessary to perform a blowing process periodically from the viewpoint of preventing the occurrence of scale, and inevitably the blowing frequency. There was a problem that there were many.

  The present invention has been made in view of such circumstances, and it is possible to effectively suppress the generation of algae, slime, scale, and the like, and to control the quality of cooling tower makeup water that can suppress corrosion of the piping system. The purpose is to provide.

In order to achieve the above object, the cooling tower make-up water quality adjusting device according to the present invention is a cooling tower make-up water quality adjusting device that adjusts the quality of make-up water supplied to the cooling tower, and contains a hardness component. A water softener that softens the hard water generated to generate soft water, a first supply path that connects the water softener and the cooling tower, and hard water that bypasses the water softener and is connected to the first supply path The second supply path through which the water passes, the control means for controlling the inflow of the hard water from the second supply path to the first supply path, and the water quality for managing the quality of the circulating water circulating through the cooling tower and a management unit, said control means have a inflow permitting means for permitting the flow into the first supply path of the hard water in accordance with the water quality conditions of the circulating water that is managed by the water quality management means, Immediately after starting operation of the cooling tower, it is constant until the target hardness is reached. While the hard water is replenished to the cooling tower, the soft water is supplied to the cooling tower after the lapse of a certain time, and thereafter, the hard water and the soft water alternately according to the water quality state of the circulating water. The cooling tower can be replenished .

Further, water conditioning apparatus of the cooling tower makeup water of the present invention, the water quality management means includes flow measuring means for measuring a total accumulated flow of the soft water and the hard water passes through the first supply passage, said inlet The permitting means, when the integrated flow rate of the soft water has measured a first predetermined value by the flow rate measuring means, the first supply path until the integrated flow rate of hard water to the cooling tower reaches a second predetermined value. It is characterized by permitting the inflow of hard water to.

Further, water conditioning apparatus of the cooling tower makeup water of the present invention, the water quality management means includes counting means for counting the replenishing time of the soft water and the hard water is supplied to the cooling tower, before Symbol inflow authorization means When the accumulated replenishment time to the cooling tower of the soft water is measured by the time measuring means for a first predetermined time, the first replenishment time until the accumulated replenishment time of hard water to the cooling tower reaches a second predetermined time. It is also preferable that the hard water is allowed to flow into the replenishment path.

Further, water conditioning apparatus of the cooling tower makeup water of the present invention, the control means, when said inlet to said first supply passage of the hard water by flowing permission unit is permitted, the cooling tower of the soft water The supply to the cooling tower is cut off, and only the hard water can be supplied to the cooling tower.

  The cooling tower makeup water quality adjusting device of the present invention is characterized in that a chlorinated aqueous solution is injected into the circulating water.

  In the cooling tower makeup water quality adjusting device of the present invention, the hard water is raw water.

According to the cooling tower makeup water quality adjusting device, the water softener that softens hard water (raw water) containing a hardness component to generate soft water, and the first supply path that connects the water softener and the cooling tower. A second supply path through which hard water that bypasses the water softener and is connected to the first supply path passes, and an inflow of the hard water from the second supply path to the first supply path Control means for controlling, and water quality management means for managing the quality of the circulating water circulating through the cooling tower and the apparatus to be cooled, wherein the control means is a water quality state of the circulating water managed by the water quality management means have a inflow permitting means for permitting the flow into the first supply path of the hard water according to, immediately after the start of operation of the cooling tower, replenishing a certain time the hard water to reach the target hardness to the cooling tower And the soft water is cooled after the predetermined time. It is fed to the column, since then is capable supplied to the cooling tower in the soft water and alternating with the hard water according to the quality conditions of the circulating water, immediately after the start of operation of the cooling tower reaches a target hardness constant Since hard water is supplied until time elapses, it is possible to operate in a stable water quality state at an early stage. Thereafter, soft water is preferentially supplied to the cooling tower via the first supply path, while hard water can be supplied to the cooling tower according to the water quality. Thereby, it can be avoided that the Langeria index L is lowered and the state is maintained, generation of algae, slime, scale, etc. can be suppressed, and corrosion of the piping system can be suppressed.

Specifically, when the cumulative flow rate of the soft water measured by the flow rate measuring means has a first predetermined value, the first replenishment path until the cumulative flow rate of hard water to the cooling tower reaches a second predetermined value. wherein allow inflows of hard water into, or when the integrated supply time to the cooling tower of the soft water has timed the first predetermined time by the timing means, the accumulated replenishment time hard water to the cooling tower is the By allowing the hard water to flow into the first replenishment path until the predetermined time of 2 is reached, the hard water is supplied to the cooling tower when the Langeria index L is lowered by the long-time operation using the soft water as circulating water. This makes it possible to replenish, thereby increasing the Langeria index L and suppressing corrosion of the piping system.

  In addition, when the inflow permission means permits the inflow of the hard water into the first supply path, the supply of the soft water to the cooling tower is interrupted and only the hard water is supplied to the cooling tower. Will be replenished. In other words, since soft water is not replenished when hard water is replenished, a calcium carbonate film is easily formed by calcium ions and hydrogen carbonate ions contained in the hard water when replenishing hard water, thereby effectively suppressing corrosion of the piping system. can do.

  Further, since the chlorinated aqueous solution is injected into the circulating water, the generation and propagation of microorganisms can be suppressed at the same time while preventing pipe corrosion.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an embodiment (first embodiment) of a water treatment system provided with a water quality adjusting device for cooling tower makeup water according to the present invention, and is downstream of the water quality adjusting device 1. On the side, an open cooling tower 2 is provided.

  Specifically, the cooling tower 2 includes a cooling tower body 3 having an opening 4 at the top, a fan 5 disposed in the opening 4, and a ventilation hole for introducing outside air to the side surface. Louvers 6 are provided in an inclined shape.

  In addition, a storage unit 7 for storing circulating water is provided at the lower part of the cooling tower body 3, and the storage unit 7 has a ball tap water tap (hereinafter referred to as “water tap”) that manages the water level of the circulating water. 8 is disposed. The water tap 8 is connected to a first supply pipe (first supply path) 9 and is configured to be able to supply water to the cooling tower body 3 of soft water or hard water.

  Here, in the present invention, “hard water” means general raw water containing hardness components including tap water, ground water, industrial water and the like.

  A blow pipe 10 is connected to the bottom of the cooling tower body 3, and a blow valve 11 is interposed in the blow pipe 10. And the circulating water in the storage part 7 is drained outside from the blow pipe 11 as needed.

  A circulation pipe 12 is connected to the bottom of the cooling tower body 3, and the tip of the circulation pipe 12 is arranged so as to be located at the top of the cooling tower body 3, and a number of nozzles 13 are attached to the tip. ing.

  Further, in the conduit of the circulation pipe 12, a circulation pump 14 that recirculates the circulating water to the upper part of the cooling tower body 3, an electrical conductivity measuring device 15 that measures the electrical conductivity of the circulating water, and the temperature of the circulating water A temperature detecting device 16 for detecting the temperature and a device to be cooled 17 such as a heat exchanger are disposed.

  As described above, the electrical conductivity measuring device 15 measures the electrical conductivity of the circulating water and manages the concentration rate of the circulating water. That is, the dilution water supply pipe 18 is connected to the cooling tower body 3, and when the dilution water supply valve 19 disposed in the pipe of the dilution water supply pipe 18 is operated, the concentration ratio becomes excessively large. Dilution water is supplied to the cooling tower body 3.

  Further, the temperature detection device 16 detects the temperature of the circulating water and performs inverter control on the motor 20 that drives the fan 5. Specifically, when the temperature of the circulating water is increased, the number of rotations of the motor 20 is increased to increase the amount of air supplied from the louver 6 to the cooling tower body 3, thereby increasing the cooling effect. On the other hand, when the temperature of the circulating water is low, the rotational speed of the motor 20 is lowered to reduce the amount of air supplied from the fan 5 to the cooling tower body 3, thereby reducing the cooling effect and suppressing power consumption.

  As described above, in the present embodiment, the motor 20 is inverter-controlled according to the detection result of the temperature detection device 16, thereby managing the suction air amount supplied into the cooling tower body 3, that is, the discharge air amount from the fan 5. ing.

  An electrolytic cell 21 is disposed upstream of the cooling tower 2, and the electrolytic cell 21 is connected to a salt water tank 23 via a salt water supply pipe 22.

  The salt water tank 23 incorporates a partition plate (not shown) for partitioning salt and saline and a float valve (not shown) for adjusting the water level in the salt water tank 23. The salt water tank 23 stores soft water from which hardness components are almost completely removed, and salt is manually added every predetermined period (for example, 3 to 4 days). And salt will be stirred and melt | dissolved in soft water, and a saturated salt solution will be produced | generated by this.

  The electrolytic cell 21 has first and second water level sensors 25a and 25b disposed on the upper side surface and the lower side surface of the electrolytic cell body 24 formed in a cylindrical shape, and an electrode is disposed on the lower side of the electrolytic cell body 24. A unit (not shown) is provided, and the electrode unit is electrically connected to the power supply device 26.

  The salt water supply pipe 22 connected to the electrolytic cell main body 24 is provided with a first valve 27a. The electrolytic cell main body 24 is connected to a soft water supply pipe 28, and a second valve 27 b is interposed in the soft water supply pipe 28.

  Further, a drain pipe 29 having a third valve 27 c interposed therein is connected to the electrolytic cell main body 24, so that the electrolytic water stored in the electrolytic cell main body 24 can be drained.

  Further, an electrolyzed water delivery pipe 30 having a fourth valve 27d interposed therein is connected to the upper part of the electrolytic cell main body 24, and a vent pipe 31 having a fifth valve 27e interposed therein is further connected.

  In the electrolytic cell 21 configured as described above, when the first valve 27a is opened after the fifth valve 27e is opened to allow ventilation with outside air, the salt water is supplied via the salt water supply pipe 22. Saturated saline is supplied from the tank 23. Next, when the second valve 27b is opened, soft water is supplied from a water softener, which will be described later, via the soft water supply pipe 28, and the saturated saline is diluted to produce about 1 to 3% by weight of diluted saline. In this state, when the electrode unit is energized with a predetermined current density from the power supply device 26, the diluted saline solution is electrolyzed in the electrolytic cell main body 24, whereby the free residual chlorine concentration is about 6000 mgCl / L. High concentration sodium hypochlorite (chlorine aqueous solution) is produced. Then, sodium hypochlorite generated in the electrolytic cell main body 24 is appropriately injected into the circulation pipe 12 through the electrolytic water delivery pipe 30.

  As shown in FIG. 2, the water quality adjusting device 1 includes a water softener 32 that generates soft water by removing hardness components contained in hard water (raw water) substantially completely. The raw water discharge pipe 46 connected to the water pump 38 is branched at a point A into a raw water supply pipe 33 and a second supply pipe (second supply path) 34. The raw water supply pipe 33 is connected to the water softener 32 through a water supply valve 39 and a flow meter 40, while the second supply pipe 34 bypasses the water softener 32 and is connected to the water softener 32. The first supply pipe 9 is joined at point B. The first supply pipe 9 merges with the diluted water supply pipe 18 at a point C located upstream of the point B.

  A first switching valve 35 is interposed between B to C of the first supply pipe 9, and a second switching valve 36 is interposed in the second supply pipe 34. Further, an integrated flow meter 37 for measuring the integrated flow rate of the soft water or the hard water is provided downstream from the point B of the first supply pipe 9.

  A drain pipe 41 is connected to the water softener 32, and a drain valve 42 is interposed in the drain pipe 41.

  The water softener 32 includes a sodium-type cation exchange resin (not shown), and when raw water is supplied through the raw water supply pipe 33, the hardness of calcium ions and magnesium ions contained in the raw water. The components are removed by ion exchange with sodium ions of the cation exchange resin, whereby the raw water is softened to become treated water. When the exchange capacity of the cation exchange resin is saturated, the saturated saline stored in the salt water tank 23 is supplied through the salt water supply pipe 43, and the cation exchange resin is regenerated. The saline used for regeneration is discharged from the drain pipe 41.

  FIG. 3 is a block diagram showing the control system of the water treatment system.

  That is, the system control unit 47 is used as an input / output unit 48 that controls interface operations with a component to be controlled, a ROM 49 that stores a predetermined calculation program, etc., and stores calculation results or is used as a work area. And a CPU 51 that incorporates a timer 51a and controls the entire system.

  In the water quality adjusting apparatus 1, the output signals of the integrating flow meter 37 and the flow meter 40 are input to the input / output unit 48, and the water supply pump 38, the water supply valve 39, and the first and second switching valves 35, 36. And an output signal to the drain valve 42. In the first embodiment, the water quality state of the circulating water supplied to the cooling tower main body 3 is managed by the integrated flow rate of the integrated flow meter 37, and the first flow rate is determined according to the measured value of the integrated flow meter 37. The switching valve 35 and the second switching valve 36 are configured to be switched.

  In addition, the input / output unit 48 includes other components 52 of the water treatment system (an electrical conductivity measuring device 15, a temperature detecting device 16, an inverter device that controls the number of rotations of the motor 20 by an inverter, and first and second water level sensors). 25a, 25b, power supply device 26, circulation pump 14, and valves 27a-27e, 11, 19, 39, 42) are electrically connected to each other and exchange signals with these components. The member is controlled by the CPU 51.

  The water treatment system configured as described above is driven to operate as follows.

  First, the motor 20 is driven through the inverter, and the fan 5 is rotated. As a result, outside air flows into the cooling tower body 3 from the direction of arrow D through the louver 6, and this outside air circulates inside the cooling tower body 3 and is discharged to the outside as indicated by arrow E. The

  On the other hand, when the water pump 38 is driven to close the first switching valve 35 and the second switching valve 36 is opened for a predetermined time (for example, 24 hours), hardness components such as tap water and industrial water are removed. The contained hard water (raw water) flows into the first supply pipe 9 via the second supply pipe 34, and the hard water is supplied to the cooling tower body 3. The hard water stored in the storage unit 7 is circulated through the circulation pipe 12 as circulating water by driving the circulation pump 14.

  When the water supply valve 39 is opened, the raw water passes through the flow meter 40 and is supplied to the water softener 32. And in this water softener 32, the soft water from which the hardness component in raw | natural water was removed substantially is produced | generated by ion exchange with the sodium ion of a cation exchange resin.

  In the first embodiment, as described above, the quality of the circulating water supplied to the cooling tower body 3 is managed by the integrated flow rate of the integrated flow meter 37, and according to the measured value of the integrated flow meter 37. The first and second switching valves 35 and 36 are controlled to be switched. That is, the hardness of the circulating water is estimated based on the integrated flow rate of soft water or hard water measured by the integrated flow meter 37, and either soft water from the water softener 32 or hard water passing through the second supply pipe 34 is cooled. The tower body 3 is supplied as make-up water, whereby the water quality is adjusted so that the circulating water has an appropriate hardness range such that the Langelia index L does not become a negative value less than “0”.

  FIG. 4 is a flowchart showing the first embodiment of the water quality adjustment processing routine, and this program is started by the operation of the water treatment system and is ended by the stop.

  First, the water pump 38 is driven by the start of operation. In step S 1, the system control unit 47 issues a hard water supply signal, closes the first switching valve 35 and opens the second switching valve 36, and passes through the first supply pipe 9. Supply of the hard water to the cooling tower body 3 is started. Next, in step S2, it is determined whether or not the timer 51a has counted a predetermined time t1.

  When the timer 51a counts the predetermined time t1, the process proceeds to step S3 where the second switching valve 36 is closed and the water supply to the cooling tower main body 3 is prohibited at the same time or almost simultaneously with the first switching valve 35. Is opened, and water supply from the water softener 32 to the cooling tower main body 3 is permitted.

  As described above, in the first embodiment, hard water is supplied to the cooling tower main body 3 at the start of operation, and soft water is supplied after a lapse of a predetermined time t1, whereby the circulating water is quickly concentrated to the target hardness. . For this reason, the Langeria index L of circulating water can be adjusted to the positive value (for example, 0.1-1.5) in which formation of a calcium carbonate film is accelerated in a short time.

  In step S4, the integrated flow rate of the soft water passing through the first supply pipe 9 is measured by the integrated flow meter 37 to determine whether or not the first predetermined value Q1 has been reached. Here, the first predetermined value Q1 is a result of supplying soft water to the cooling tower body 3 for a long time, that is, as a result of diluting the hardness component in the circulating water by supplying soft water accompanying evaporation or scattering of the circulating water. The integrated flow rate value is set such that the calcium film cannot be maintained, for example, the Langeria index L is zero.

  When the integrated flow meter 37 reaches the first predetermined value Q1, the process proceeds to step S5, where the system control unit 47 closes the first switching valve 35 and prohibits the water supply to the cooling tower body 3 from soft water. Then, the second switching valve 36 is opened simultaneously or substantially simultaneously, thereby permitting the inflow of hard water into the first replenishment path 9 and allowing the cooling tower main body 3 to be replenished.

  Subsequently, it progresses to step S6 and it is judged whether the integrating | accumulating flowmeter 37 measured the 2nd predetermined value Q2. Here, the second predetermined value Q2 is set to an integrated flow rate value of hard water such that the Langeria index L of the circulating water becomes a positive value again.

  When the integrated flow meter 37 reaches the second predetermined value Q2, the process returns to step S3, and the system control unit 47 closes the second switching valve 36 to prohibit water supply to the cooling tower main body 3. Then, the first switching valve 35 is opened simultaneously or substantially simultaneously, and water supply from the water softener 32 to the cooling tower body 3 is permitted again.

  Thereafter, the operations of Step S3 to Step S6 are repeated, and hard water and soft water are alternately supplied to the cooling tower main body 3 to avoid the Langeria index L from continuing to be “0” or less for a long time, thereby preventing pipe corrosion. Suppresses the occurrence.

  In addition, since the supply of hard water or soft water to the cooling tower body is controlled by the faucet 8, even if the system control unit 47 issues a water supply permission signal of hard water or soft water, the circulating water stored in the storage unit 7 Hard water or soft water is replenished to the cooling tower body 3 only when the amount of water decreases due to evaporation or scattering.

  As described above, in the first embodiment, hard water and soft water can be replenished alternately by switching the first and second switching valves 35 and 36, so slime and scale are generated by the soft water. On the other hand, since hard water is replenished as necessary, the water quality of the circulating water can be managed in an appropriate range so that the Langeria index L does not become “0” or less for a long time. Corrosion can be effectively suppressed.

  In particular, during operation of the cooling tower 2, the sodium hypochlorite aqueous solution generated in the electrolytic cell 24 is appropriately injected into the circulating water to suppress the growth of bacteria, but by the injection of the sodium hypochlorite aqueous solution, Free residual chlorine is generated and may be easily corroded. However, in the first embodiment, even when a sodium hypochlorite aqueous solution is injected into the circulating water, by replenishing raw water (hard water) having a hardness component as necessary, Corrosion resistance can be improved.

  FIG. 5 is a time chart showing a state where soft water or hard water can be supplied to the cooling tower 2.

  First, at the start of operation, hard water is replenished for a fixed time t1, and then the water supply is switched from hard water to soft water. When the integrated flow rate of soft water reaches a time t2 corresponding to the first predetermined value Q1, the Langeria index L decreases. Judgment water is switched to hard water. After that, when the integrated flow rate reaches a time t3 corresponding to the second predetermined value Q2, it is determined that the Langeria index L has risen to the extent that there is no risk of corrosion due to the replenishment of hard water, and it is switched to soft water again. Thereafter, soft water (time t2) and hard water (time t3) are alternately supplied.

  FIG. 6 is a conceptual diagram showing the relationship between the operating time and the hardness of the circulating water. The broken line indicates a comparative example (Patent Document 1), and the solid line indicates the present invention. The horizontal axis represents the operating time, and the vertical axis represents the hardness of the circulating water.

  In order to suppress corrosion of the piping system, it is necessary to set a target hardness H (for example, a hardness such that the Langeria index L is 0.1 to 1.5) and to stably operate with water quality in the vicinity of the target hardness H. There is.

  However, in the comparative example, since the cooling water is supplied to the cooling tower immediately after the start of operation, it takes time for the circulating water to reach the target hardness H. It takes time.

  In addition, in the comparative example, since the mixed water of hard water and soft water is replenished as described above, the concentration of the hardness component is easy to proceed, and from the viewpoint of preventing the generation of scale, as shown in FIG. Processing is required.

  In contrast, in the present invention, since the hard water is replenished for a certain time immediately after the start of operation, the target hardness H can be reached early. And when fixed time t1 passes, makeup water is switched from hard water to soft water, and it can rush to stable operation at an early stage.

  In addition, in the present invention, since hard water is replenished only when necessary, it is possible to avoid excessive concentration during operation, and to reduce the frequency of blow processing.

  Next, a second embodiment of the present invention will be described.

  In the second embodiment, the water quality state of the circulating water is managed by the timer 51a built in the CPU 51 instead of the integrating flow meter 37, that is, the timer 51a supplies the cooling water to the cooling tower body 3 with soft water or hard water. The accumulated water supply time is counted, and the first and second switching valves 35 and 36 are controlled to be switched according to the timing results, thereby adjusting the quality of the circulating water as in the first embodiment. Yes.

  FIG. 7 is a flowchart showing a second embodiment of the water quality adjustment processing routine, and this program is started by the operation of the water treatment system and is ended by the stop.

  First, when the operation is started, the water pump 38 is driven. In step S11, as in the first embodiment, hard water is supplied to the cooling tower main body 3 through the first supply pipe 9, and in step S12, the process waits for a fixed time t1.

  When the predetermined time t1 has elapsed, the process proceeds to step S13, and when the second switching valve 36 is closed and water supply to the cooling tower body 3 is prohibited, the first switching valve 35 is opened simultaneously or substantially simultaneously. The water supply from the water softener 32 to the cooling tower main body 3 is permitted.

  In step S14, an accumulated replenishment time of soft water replenished to the cooling tower main body 3 through the first replenishment pipe 9 is counted by the timer 51a, and whether or not the replenishment accumulated time has passed the first predetermined time T1. Judging. Here, the first predetermined time T1 is a result of supplying soft water to the cooling tower body 3 for a long time, that is, as a result of diluting the hardness component of the circulating water by supplying soft water accompanying evaporation or scattering of the circulating water. The state is set such that the calcium film cannot be maintained, for example, the time when the Langeria index L becomes zero.

  Then, when the first predetermined time T1 has elapsed, the process proceeds to step S15, and the system control unit 47 closes the first switching valve 35 and prohibits the water supply to the cooling tower body 3 at the same time or substantially simultaneously. The second switching valve 36 is opened to allow the hard water to flow into the first supply path 9 and to supply water to the cooling tower body 3.

  Next, the process proceeds to step S16, and it is determined whether or not the hard water replenishment integration time has passed the second predetermined time T2. Here, the second predetermined time T2 is set to a water passing time such that the Langeria index L of the circulating water becomes a positive value again.

  When the second predetermined time T2 elapses, the process returns to step S13, and the system control unit 47 closes the second switching valve 36 and prohibits water supply to the cooling tower body 3 at the same time or substantially simultaneously. The first switching valve 35 is opened, and water supply from the water softener 32 to the cooling tower main body 3 is permitted.

  Thereafter, the operations of Step S13 to Step S16 are repeated, and hard water and soft water are alternately supplied to the cooling tower body 3, and the Languelia index L is maintained for a long time to be "0" or less to prevent pipe corrosion. Suppresses the occurrence.

  As described above, in the second embodiment, the first and second switching valves 35 and 36 are controlled to be switched according to the time measured by the timer 51a, so that hard water and soft water are alternately supplied. Thus, as in the first embodiment, soft water is mainly replenished as circulating water to suppress generation of slime and scale, while hard water is replenished as necessary, so that the water quality is moderate. Therefore, the corrosion of the piping system can be effectively suppressed.

  The present invention is not limited to the above embodiment. In the first embodiment, soft water and hard water are alternately supplied based on the measured value of the integrated flow meter 37, and in the second embodiment, soft water and hard water are alternately supplied based on the integrated supply time of the timer 51a. However, the soft water replenishment time may be controlled based on an integrated flow meter, and the hard water replenishment time may be controlled based on a timer, or conversely, the soft water replenishment time may be controlled based on a timer. The hard water replenishment time may be controlled based on an integrated flow meter. In the first and second embodiments, the hard water supply time immediately after the start of operation is managed by the timer 51a, but may be managed by a flow meter.

In the first and second embodiments, the water supply timing of soft water or hard water may be varied as required.

  Moreover, in the water treatment system, the electrolysis treatment of the diluted saline solution is performed by constant voltage control, but may be performed by constant current control.

  Furthermore, in the water treatment system of FIG. 1, an open type cooling tower is illustrated, but it goes without saying that it can be similarly applied to a closed type cooling tower.

  Moreover, although the case where one water softener was used was demonstrated in the said embodiment, a some water softener may be connected and it may be made to switch a water softening process suitably.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows one Embodiment (1st Embodiment) of the water treatment system provided with the water quality adjustment apparatus of the cooling tower makeup water based on this invention. It is an enlarged block diagram of the said water quality adjustment apparatus. It is a block block diagram which shows the control system of a water treatment system. It is a flowchart which shows 1st Embodiment of a water quality adjustment process routine. It is a time chart which shows hard water, soft water, and replenishment timing. It is the conceptual diagram which showed the relationship between operation time and the hardness of circulating water with the comparative example. It is a flowchart which shows 2nd Embodiment of a water quality adjustment process routine.

Explanation of symbols

9 First supply pipe (first supply path)
32 Water softener 34 Second supply pipe (second supply path)
35 1st switching valve (control means)
36 Second switching valve (control means)
37 Flowmeter (Water quality management means)
47 System controller (control means)
51a timer (water quality management means)

Claims (6)

A cooling tower make-up water quality adjusting device for adjusting the quality of make-up water supplied to the cooling tower,
A water softener that softens hard water containing a hardness component to generate soft water, a first supply path that connects the water softener and the cooling tower, and bypasses the water softener to the first supply path. A second supply path through which the hard water to be connected passes, control means for controlling the inflow of the hard water from the second supply path to the first supply path, and the quality of the circulating water circulating through the cooling tower Water quality management means to manage,
It said control means, have a flowing permission means for permitting the flow into the first supply path of the hard water in accordance with the water quality conditions of the circulating water that is managed by the water quality management means,
Immediately after the start of operation of the cooling tower, the hard water is replenished to the cooling tower for a predetermined time until the target hardness is reached, and after the fixed time has elapsed, the soft water is supplied to the cooling tower, and thereafter the circulating water is supplied. The cooling tower make-up water quality adjusting device is characterized in that the hard water and the soft water can be supplied to the cooling tower alternately according to the water quality state . The water quality management means includes flow measuring means for measuring a total accumulated flow of the soft water and the hard water passes through the first supply passage,
When the integrated flow rate of the soft water has measured the first predetermined value by the flow rate measuring unit, the inflow permission unit has the first flow rate until the integrated flow rate of hard water to the cooling tower reaches a second predetermined value . water conditioning apparatus of the cooling tower makeup water according to claim 1, wherein allowing inflow of the hard water to supply route. The water quality management means includes time measuring means for measuring the replenishment time of the soft water and hard water replenished to the cooling tower,
The inflow permitting means sets the accumulated replenishment time of hard water to the cooling tower to a second predetermined time when the accumulated replenishment time of the soft water to the cooling tower has timed the first predetermined time. The water quality adjusting device for cooling tower make-up water according to claim 1 or 2, wherein the hard water is allowed to flow into the first make-up path until it reaches.   When the inflow permission means permits the inflow of the hard water into the first replenishment path, the control means shuts off the supply of the soft water to the cooling tower and passes only the hard water to the cooling tower. The water quality adjusting device for cooling tower makeup water according to any one of claims 1 to 3, wherein water supply is possible. The water quality adjusting device for cooling tower makeup water according to any one of claims 1 to 4 , wherein a chlorinated aqueous solution is injected into the circulating water . The water quality adjusting device for cooling tower makeup water according to any one of claims 1 to 5, wherein the hard water is raw water.

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