JP5206308B2 - Circulating water system operation control device and circulating water system operating method - Google Patents

Description

  The present invention relates to a circulating water system operation control device and a circulating water system operating method, and more specifically, a circulating water system that directly or indirectly cools a cooled device such as a heat exchanger using circulating water into which a chemical has been injected. It is related with the operation control apparatus of this, and the operating method of a circulating water system.

  2. Description of the Related Art Conventionally, in air conditioning equipment such as commercial buildings and various factories, a system that cools a device to be cooled such as a heat exchanger by circulating makeup water supplied to a cooling tower has been widely used.

  In this type of system, when the makeup water is circulated, the circulating water is concentrated by evaporation of water, and dissolved salts and the like 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. Moreover, Legionella bacteria propagate by the said slime etc., and there exists a possibility that the propagated Legionella bacteria may be accompanied by scattered water and sprayed in air | atmosphere. Furthermore, there is a possibility that scale is deposited due to the concentration of the hardness component or silica and adheres to the apparatus to be cooled, resulting in a decrease in thermal efficiency.

  Therefore, as described in Non-Patent Document 1, conventionally, a part of the concentrated circulating water is appropriately drained out of the system so that the dissolved salts and the like in the circulating water are not excessively concentrated. Blow control for supplying and diluting the circulating water is performed, and chemicals such as anticorrosives and scale preventives are injected into the circulating water to operate the cooling tower.

  For example, in Patent Document 1, a makeup water amount measuring means for measuring a makeup water amount to the circulating water system, a water quality measuring means for measuring the quality of the circulating water, a makeup water amount measuring means, and information from the water quality measuring means are used. A water treatment chemical injection control system in a circulating water system comprising a control means for controlling the amount of water treatment chemical injection and a water treatment chemical injection means for injecting water treatment chemical based on information from the water treatment chemical injection control means. Proposed.

  In this Patent Document 1, a chemical injection amount (water treatment chemical injection amount) corresponding to the concentration rate of circulating water is calculated, and the chemical injection amount is injected when the concentration rate is low by injecting the chemical injection amount into the circulating water. The concentration is increased and the concentration is decreased as the concentration rate is increased, thereby controlling the concentration of the drug in the circulating water within an appropriate range. That is, in patent document 1, the chemical | medical agent density | concentration of a circulating water system is manageable by correct | amending a chemical injection amount according to a concentration rate.

  Patent Document 2 relates to a boiler. A flow meter with pulse oscillation is inserted in a water supply line, and a pulse oscillation unit of the flow meter with pulse oscillation and a drive unit of an electromagnetically driven chemical injection pump are connected to a signal line. A chemical injection device linked with the above has been proposed.

  Since the boiler feed water supplied to the boiler is concentrated in the can, the boiler water is appropriately blown while operating while injecting the chemical into the boiler feed water, as in the cooling tower. And in this patent document 2, the pulse signal (flow rate pulse) proportional to the amount of water supply is oscillated by the flow meter with pulse oscillation, and the electromagnetically-driven chemical injection pump is driven by the pulse signal, whereby the amount is proportional to the amount of water supply. In this way, the chemical concentration in the boiler feed water is made constant.

  FIG. 11 is a time chart showing the relationship between the chemical injection timing and the blow timing when the chemical injection device of Patent Document 2 is applied to a circulating water system such as a cooling tower.

  That is, a flow rate pulse corresponding to the amount of makeup water is output from the flow meter with pulse oscillation, as shown in FIG. And as shown in FIG.11 (c), an electromagnetic drive chemical injection pump drives for every predetermined flow rate pulse (for example, 5 flow rate pulses), and a chemical | medical agent is intermittently inject | poured into circulating water with a predetermined pulse width.

  On the other hand, when the makeup water is circulated, the circulating water is concentrated, so that the impurity concentration becomes high and the electrical conductivity increases. Then, as shown in FIG. 11A, when the electrical conductivity of the circulating water reaches the first predetermined value e1, a part of the circulating water is blown out of the system as shown in FIG. In addition, the makeup water is forcibly supplied to the cooling tower and the circulating water is diluted. The concentration of the circulating water is reduced by the dilution of the circulating water, the electric conductivity is lowered to the second predetermined value e2, and the blow is finished.

  In addition, Patent Document 1 and Non-Patent Document 1 do not describe the relationship between the chemical injection timing and the blow timing, but as in FIG. 11, the circulating water is blown in the drainage period defined by the electrical conductivity, The drug seems to be injected into the circulating water at predetermined intervals.

JP 2002-159962 A JP 59-4806 Shuichi Takada and Koshi Kawahara "Energy-saving technology practice series 2nd edition cooling tower", Energy Conservation Center Foundation, April 16, 2003, p. 83-91

  As described above, in the conventional circulatory system operation control device, the medicine injection timing and the blow timing are not linked, and the blow control is performed regardless of the medicine injection during the drainage period t defined by the electrical conductivity. It is common.

  For this reason, as shown in FIG. 11 described above, the blow timing and the medicine injection timing overlap in time, and there is a possibility that the medicine is injected even during the draining period t that is blowing.

  However, when the medicine is injected during the drainage period t, the injected medicine is not circulated in the system, but is drained out of the system together with the blow water (circulated water drained at the time of blow). There is a risk that the medicine is consumed in vain.

  The present invention has been made in view of such circumstances, and the drug injected into the circulating water is immediately drained and wasted while maintaining the concentration of the drug in the circulating water within an appropriate range. An object of the present invention is to provide a circulating water system operation control apparatus and a circulating water system operating method that can be avoided.

  In order to achieve the above object, an operation control device for a circulating water system according to the present invention includes a cooling tower that is supplied with makeup water and that directly or indirectly cools a cooled device using the makeup water as circulation water, and the circulation A medicine injection means for injecting medicine into the water; a water quality detection means for detecting the quality of the circulating water; and a drainage means for draining a part of the circulating water to the outside according to a detection result of the water quality detection means. In the circulating water system operation control device, during the drainage period in which a part of the circulating water is drained out of the system by the drainage means, the medicine injection prohibiting means for prohibiting the injection of the medicine and the flow rate of the makeup water are detected. A flow rate detection means; a makeup water amount storage means for storing a makeup water amount during the drainage period based on a detection result of the fluid flow detection means; and a drug amount corresponding to the makeup water amount stored in the makeup water amount storage means for the passage of the drainage period. After said circulation It is characterized by having a refill injection means for replenishing injected into.

  In the circulating water system operation control device according to the present invention, the makeup water amount storage means stores a count value of a flow rate pulse generated by the flow rate detection means.

  Furthermore, the operation control device for the circulating water system according to the present invention includes a cooling tower for supplying makeup water and cooling the cooled device directly or indirectly using the makeup water as the circulating water, and injecting the chemical into the circulating water. A circulating water system comprising: a medicine injecting means, a water quality detecting means for detecting the quality of the circulating water, and a draining means for draining a part of the circulating water out of the system according to a detection result of the water quality detecting means. In the operation control apparatus, a drainage period calculating means for calculating a drainage period for draining part of the circulating water to the outside by the drainage means, a medicine injection prohibiting means for prohibiting the injection of the medicine during the drainage period, A constant flow rate adjusting means for making the flow rate of makeup water constant, a drug amount calculating means for calculating a drug amount based on a set flow rate of the constant flow rate adjusting means and a calculation result of the drainage period calculating means, and the drug amount Calculated by calculation means It is characterized in that the agent amount and a refill injection means for replenishing injected into the circulating water after the drain period.

  The circulating water system operation control device of the present invention is a drainage prohibiting means for prohibiting draining of the circulating water outside the system for a predetermined period after injection of the drug when the drug is injected into the circulating water. It is characterized by having.

  Further, the operation method of the circulating water system according to the present invention supplies makeup water to the cooling tower, uses the makeup water as the circulation water to cool the cooled device directly or indirectly, and supplies the circulating water with the chemical. In the operation method of the circulating water system in which a part of the circulating water is drained out of the system according to the quality of the circulating water while injecting the In addition to prohibiting injection, the flow rate of the makeup water is detected, the makeup water amount during the drainage period is stored from the detection result, and the amount of medicine corresponding to the stored makeup water amount after the drainage period has elapsed It is characterized by supplementary injection.

  The operating method of the circulating water system according to the present invention is characterized in that the count value of the flow rate pulse is stored as the makeup water amount.

  Furthermore, the operation method of the circulating water system according to the present invention supplies makeup water to the cooling tower, uses the makeup water as circulating water to cool the cooled device directly or indirectly, and supplies the circulating water with a chemical. In the operation method of the circulating water system in which a part of the circulating water is drained out of the system according to the quality of the circulating water while injecting the In addition to prohibiting injection, the amount of medicine is calculated based on the set flow rate of the makeup water and the drainage period, and the amount of medicine is supplemented and injected into the circulating water after the drainage period has elapsed.

  Further, the operation method of the circulating water system according to the present invention is characterized in that, when the chemical is injected into the circulating water, draining the circulating water out of the system is prohibited for a predetermined period after the injection of the chemical. .

  According to the above circulating water system operation control device and circulating water system operating method, the injection of chemicals is prohibited during the drainage period, while the amount of makeup water (the count value of the flow rate pulse) during the drainage period is stored, and the drainage Since the amount of medicine according to the amount of makeup water during the period is replenished and injected into the circulating water after the drainage period has elapsed, the medicine concentration in the circulating water is kept within the proper range while avoiding that the medicine just injected is drained together with the blow water. Can be maintained. This can prevent wasteful consumption of the medicine.

  In addition, while prohibiting the injection of chemicals during the drainage period, the amount of makeup water during the drainage period is calculated from the drainage period and the set flow rate of makeup water, and the amount of medicine according to the amount of makeup water is further calculated. Since the amount of drug is replenished and injected into the circulating water after the drainage period has elapsed, the drug concentration in the circulating water can be maintained within an appropriate range while avoiding draining of the just-injected drug with the blow water, as described above. It becomes possible, and it can prevent that a chemical | medical agent is consumed wastefully.

  As described above, according to the present invention, the medicine injection and the blow control are linked to each other so that the medicine injection and the blow control do not overlap with each other in time, and the necessary amount of the medicine is compensated after the blow control. It is possible to avoid wasteful consumption of the drug while maintaining the drug concentration at an appropriate concentration, and to optimize the amount of drug used.

  Also, when a drug is injected into the circulating water, draining the circulating water outside the system is prohibited for a predetermined period after the injection of the drug, so that the injected drug is not immediately drained out of the system. This can be prevented more effectively.

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

  FIG. 1 is a system configuration diagram showing a first embodiment of an operation control device for an open cooling tower (hereinafter simply referred to as “cooling tower”) as a circulating water system according to the present invention.

  The cooling tower 1 has a cooling tower body 2 having an opening 3 at the top, a fan 4 is disposed in the opening 3, and a louver 5 as a vent hole for introducing outside air is inclined on the side surface. Is provided.

  In addition, a storage unit 6 for storing makeup water serving as circulating water is provided at the lower part of the cooling tower body 2, and a part of the circulating water is blown into the storage unit 6 by using overflow to make it out of the system. A blow pipe 7 for draining is provided.

  A ball tap type water tap (hereinafter referred to as “water tap”) 9 for managing the water level in the storage unit 6 is disposed at the lower portion of the cooling tower body 2. A replenishment water line 10 is connected to the faucet 9 and a flow meter 11 is interposed in the replenishment water line 10 so that the replenishment water is supplied to the storage unit 6 as circulating water. ing. Further, the flow meter 11 generates a pulse signal (hereinafter referred to as “flow rate pulse”) according to the amount of makeup water, and transmits the pulse signal to a control unit described later.

  A forced water supply line 12 is branched from the water supply line 10 on the downstream side of the flow meter 11. The forced water supply line 12 is provided with an electric valve 13, and even when the water supply stop is provided by the water tap 9, the makeup water is supplied from the forced water supply line 12 to the storage unit 6, thereby circulating. A part of the water is configured to overflow the blow pipe 7 so that the circulating water can be diluted and drained. That is, the forced water supply line 12, the motor operated valve 13, and the blow pipe 7 are configured to function as drainage means by forced water supply.

  The type of makeup water is not particularly limited, and raw water such as tap water, well water, ground water, industrial water, etc. can be used. Moreover, the raw | natural water which processed these raw | natural water with an ion exchange resin etc., and was made into soft water or demineralized water can also be used for makeup water.

  In addition, an electrical conductivity sensor (water quality detection means) 14 is inserted in the reservoir 6 to detect the electrical conductivity of the circulating water. When the electrical conductivity becomes excessively large, the motor-operated valve 13 is opened, and a part of the circulating water overflows the blow pipe 7 by forcibly supplying makeup water from the forced water supply line 12 to the reservoir 6. Then, the water is drained out of the system and the circulating water is diluted.

  In this way, the concentration rate of the circulating water can be reduced, whereby the concentration rate of the circulating water is managed.

  Further, a chemical injection device 15 is attached to the cooling tower body 2. This medicine injection device 15 stores a medicine (not shown) and a medicine injection device main body 16 in which a medicine injection pump 16a is incorporated, a nozzle 17 connected to the medicine injection pump 16a and inserted in the storage section 6; have. The medicinal pump 16a is intermittently driven with a predetermined pulse width in accordance with the flow rate pulse generated by the flow meter 11, so that the medicine is injected into the circulating water as necessary.

  In addition, as a chemical | medical agent stored by the chemical injection apparatus main body 16, the multi-agent which shows each effect | action of anticorrosion / anti-scale agent or anti-corrosion / anti-scale / sterilization can be used. Here, as the anticorrosion / scaling preventive agent, polymer polymers mainly composed of polymaleic acid or polyacrylic acid, azoles mainly composed of benzotriazole or tolyltriazole, 1-hydroxyethylidene-1,1-diphosphonic acid Examples thereof include phosphonic acids mainly composed of (HEDP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC). Moreover, as a multi agent, what mixed antibacterial agents, such as an isothiazoline compound and bronopol, in addition to the anti-corrosion and anti-scale agent mentioned above can be mentioned.

  A circulation pipe 18 is connected to the storage section 6, and the tip of the circulation pipe 18 is disposed so as to be positioned below the fan 4, and a number of nozzles 19 are mounted on the tip.

  Further, in the pipe line of the circulation pipe 18, a circulation pump 20 that recirculates the circulating water to the upper portion of the cooling tower body 2, a temperature sensor 21 that detects the temperature of the circulating water, and a cooled device 22 such as a heat exchanger. Are arranged.

  The temperature sensor 21 detects the temperature of the circulating water and performs inverter control of the motor 23 that drives the fan 4. Specifically, when the temperature of the circulating water is increased, the number of rotations of the motor 23 is increased to increase the amount of air supplied from the louver 5 to the cooling tower body 2, thereby increasing the cooling effect. On the other hand, when the temperature of the circulating water is low, the rotational speed of the motor 23 is lowered to reduce the amount of air supplied from the fan 4 to the cooling tower body 2, thereby reducing the cooling effect and suppressing power consumption.

  As described above, in this embodiment, the motor 23 is inverter-controlled according to the detection result of the temperature sensor 21, thereby managing the amount of suction air supplied into the cooling tower body 2, that is, the amount of air discharged from the fan 4. Yes.

  FIG. 2 is a block configuration diagram showing a control system of the cooling tower according to the first embodiment.

  That is, the control unit 24 is used as an input / output unit 25 that controls an interface operation with a component to be controlled, a ROM 26 that stores a predetermined calculation program, and the like, and stores calculation results and is used as a work area. RAM 27 and CPU 28 for controlling the entire system.

  Then, output signals from the flow meter 11, the electrical conductivity sensor 14 and the temperature sensor 21 are input to the input / output unit 25, and output signals from the control unit 24 are supplied to the chemical injection pump 16 a, the motor operated valve 13 and the circulation pump 20. Entered. Further, an inverter device 29 is electrically connected to the input / output unit 25 to exchange signals with the inverter device 29, control the power frequency of the motor 23, and change the rotational speed of the motor 23.

  The cooling tower configured as described above is operated and controlled as follows.

  In FIG. 1, first, the fan 4 is rotated by driving the motor 23. As a result, outside air flows into the cooling tower body 2 from the direction of arrow A through the louver 5, and this outside air circulates inside the cooling tower body 2 and is discharged to the outside as shown by arrow B. The

  Then, make-up water is continuously supplied from the water supply line 10 to the cooling tower body 2 until the water supply is stopped by the water tap 9 and stored in the storage unit 6. In parallel with this, the flow meter 11 emits a flow pulse as the makeup water passes, and the flow pulse is transmitted to the control unit 24. And the control part 24 which received the flow rate pulse transmits a drive signal to the chemical injection pump 16a for every predetermined flow rate pulse (for example, 5 pulses). Receiving this drive signal, the medicine pump 16a discharges the medicine from the nozzle 17 with a predetermined pulse width, and intermittently injects it into the replenishing water so that the medicine concentration falls within the proper range.

  The makeup water stored in the storage unit 6 is circulated through the circulation pipe 18 as circulating water by driving the circulation pump 20 to cool the cooled device 22.

  On the other hand, the electrical conductivity sensor 14 constantly monitors the electrical conductivity of the circulating water. If the electrical conductivity exceeds the first predetermined value E1, it is determined that the circulating water is excessively concentrated, and the motor-operated valve 13 is opened. Start blow control. That is, a part of the circulating water is overflowed from the blow pipe 7 and discharged while forcibly supplying the replenishing water via the forced water supply line 12 to dilute the circulating water. Then, when the electrical conductivity decreases to the second predetermined value E2, the motor-operated valve 13 is opened to stop the forced supply of makeup water, and the blow control is terminated.

  And in this 1st Embodiment, the control part 24 prevents the injection | pouring of a chemical | medical agent during the drainage period which drains a part of circulating water out of the system, and the amount of replenishment water during the said drainage period A replenishing water amount storage means for storing (flow rate pulse count value), and a replenishment injecting means for replenishing and injecting a chemical amount corresponding to the replenishing water amount stored in the replenishing water amount storage means into the circulating water after the drainage period. doing.

  FIG. 3 is a flowchart showing the operation control procedure of the cooling tower according to the first embodiment, and this program is started by the operation of the cooling tower and is ended by the stop.

  In step S1, chemical injection control is performed. First, makeup water is supplied from the makeup water line 10 to the storage unit 6, and the flow meter 11 emits a flow rate pulse corresponding to the amount of makeup water and transmits it to the control unit 24. And the control part 24 transmits a drive signal to the chemical injection pump 16a for every predetermined flow rate pulse (for example, 5 flow rate pulses), and circulates the chemical | medical agent stored by the chemical injection apparatus main body 16 with the predetermined pulse width from the nozzle 17. Inject. Further, when the makeup water is stopped by the water tap 9, the flowmeter 11 does not emit a flow pulse, so that the medicine injection is stopped.

  Next, in step S2, it is determined whether or not blow control is to be started. If the answer is negative (No), that is, if blow control is not performed, the process returns to step S1 to continue the above-described chemical control. Specifically, it is determined whether or not to start the blow control based on the electrical conductivity of the circulating water detected by the electrical conductivity sensor 14. If the electrical conductivity is less than the first predetermined value E1, the impurity concentration is low and the concentration rate of the circulating water is also low, so the answer to step S2 is negative (No), the blow control is not performed, and the chemical control is executed. To do.

  On the other hand, if the electrical conductivity exceeds the first predetermined value E1, the impurity concentration is high and the concentration rate of the circulating water is also high, so the answer to step S2 is affirmative (Yes) and blow control is started. That is, in this case, the medicine injection is prohibited in step S3 and the blow is executed. Specifically, the medicine injection pump 16a is stopped to stop the injection of the medicine, the motor-operated valve 13 is opened, and makeup water is supplied from the forced water supply line 12 to the storage unit 6 to dilute the circulating water. A part of the circulating water is overflowed from the blow pipe 7 and discharged outside the system. At the same time, counting of flow rate pulses generated by the flow meter 11 is started and sequentially stored in the RAM 27.

  Next, in step S4, it is determined whether or not to end the blow control. If the electrical conductivity detected by the electrical conductivity sensor 14 has not decreased to the second predetermined value E2 (<E1), the blow control needs to be executed, so the answer to step S4 is negative (No )

  On the other hand, when the electric conductivity is less than the second predetermined value E2, the concentration factor is sufficiently lowered. Therefore, the answer to step S4 is affirmative (Yes), and the blow control ends.

  If the answer to step S4 is affirmative (Yes) and it is determined that the blow control has ended, the flow rate pulse count ends in step S5, and in the subsequent step S6, the flow rate pulse count value, that is, during the drainage period. Replenish and inject the amount of medicine according to the amount of makeup water into the circulating water. For example, in the case of performing drug injection once every 5 flow rate pulses in the drug control in step S1, when the total number of flow rate pulses counted in step S3 is 10, the drug for two times continuously with a predetermined pulse width. Refill the volume with circulating water.

  And after that, it returns to step S1 and performs the medicine injection control mentioned above.

  FIG. 4 is a time chart showing the relationship between the chemical injection timing and the blow timing. In the figure, T2 is a drainage period during which the motor-operated valve 13 is opened and blow control is performed, and T1 and T3 are blow controls. This is a non-drainage period in which chemical injection control is performed without performing the above.

  In the non-drain periods T1 and T3, as shown in FIGS. 4B and 4C, when the flow meter 11 emits a flow pulse, the drug is flowed at a predetermined pulse width every predetermined flow pulse, for example, every 5 flow pulses. Injected into the circulating water almost in synchronization with the occurrence of That is, in the non-drainage periods T1 and T3, a chemical amount proportional to the makeup water amount is injected into the circulating water, and chemical injection control is executed.

  Thereafter, when the concentration ratio of the circulating water increases with the passage of time and the impurity concentration increases, the electrical conductivity increases. Then, as shown in FIG. 4 (a), when the electrical conductivity reaches the first predetermined value E1, as shown in FIG. 4 (d), a drainage period T2 is entered. In this drainage period T2, while injecting the medicine, the makeup water is supplied from the forced water supply line 12 to the reservoir 6 to dilute the circulating water, and a part of the circulating water is blown from the blow pipe 7 Drain. And if electrical conductivity falls to the 2nd predetermined value E2, drainage of blow water will be ended.

  On the other hand, since the count value of the flow rate pulse during the drainage period T2 is stored in the RAM 27, the chemical injection pump 16a is driven when the drainage period T2 ends, and the count value of the flow rate pulse, that is, the amount of makeup water during the drainage period T2 The amount of drug corresponding to the amount is replenished and injected into the circulating water. That is, as described above, for example, when drug injection is performed by driving the drug injection pump 16a every 5 flow pulses at the time of drug control, and 10 flow pulses are counted during the drainage period T2, After the drainage period T2, the drug injection pump 16a is continuously driven twice with a predetermined pulse width to replenish and inject the medicine into the circulating water.

  As described above, in the first embodiment, while the injection of the medicine is prohibited during the drainage period T2, the flow rate pulse during the drainage period T2 is counted and stored, and after the drainage period T2, the drainage period T2 is counted. Since the medicine corresponding to the count value of the flow rate pulse is replenished and injected into the circulating water, the medicine just injected is not drained together with the blow water, and it is possible to avoid wasteful consumption of the medicine. In addition, the chemical concentration of the circulating water can always be maintained within an appropriate range.

  That is, in the first embodiment, operation control is performed by linking drug injection and blow control so that drug injection and blow control do not overlap in time, and a necessary amount of drug is compensated after blow control. Therefore, wasteful consumption of the medicine can be avoided while maintaining the medicine concentration at an appropriate concentration, and the amount of medicine used can be optimized.

  In addition, as a method of preventing the chemical injection timing and the blow timing from overlapping in time, the chemical injection timing can be controlled by a timer while the blow timing is controlled by electric conductivity. In this case, for example, (i) a method of prioritizing drug injection and delaying the start of the drainage period for blow control by a timer for a predetermined time in order to avoid the time overlap between the drug injection timing and the blow timing. Alternatively, (ii) a method of giving priority to the blow control and injecting the drug after the blow is finished can be considered.

  However, the above method (i) requires a separate timer for delaying the blow control, and also delays the blow control. Therefore, the concentration of circulating water is promoted, and there are problems such as scale generation and corrosion. May be brought in early. In addition, the method (ii) requires a separate timer for prioritizing the blow timing over the drug injection, and the electrical conductivity has reached the first predetermined value E1 so as not to overlap the drug injection timing. Even if it is not, blow control must be performed. Therefore, a part of the circulating water is drained at a stage where the concentration ratio is still low, and there is a possibility that the water is drained wastefully. Furthermore, in both methods (i) and (ii), since the injection of medicine is controlled by a timer, there is a possibility that variation in the concentration of chemical injection in the circulating water may occur if the flow rate of the makeup water fluctuates. It may be difficult to maintain the drug concentration within an appropriate range.

  On the other hand, in the first embodiment, the medicine is injected according to the flow rate pulse generated by the flow meter 11, and the required amount of medicine is replenished and injected after the drainage period T2 has elapsed. The chemical concentration in the circulating water can always be maintained within the proper range without being wasted or wasted, and it is possible to effectively prevent pipe corrosion and scale generation. It becomes.

  FIG. 5: is a system block diagram which shows 2nd Embodiment about the operation control apparatus of the cooling tower as a circulating water system which concerns on this invention.

  In the cooling tower according to the first embodiment, the flow meter 11 is interposed in the makeup water line 10, but in the cooling tower according to the second embodiment, the constant flow valve 8 ( A constant flow rate means) is provided.

  FIG. 6 is a block diagram showing a cooling tower control system according to the second embodiment. In the second embodiment, the drainage period T2 during blow control is measured by the timer 28a 'built in the CPU 28', and the amount of makeup water during the drainage period T2 is determined from the drainage period T2 and the set flow rate of the constant flow valve 8. The amount of chemicals corresponding to the amount of replenished water supplied during the drainage period is injected after the drainage period.

  FIG. 7 is a flowchart showing the operation control means of the cooling tower according to the second embodiment, and this program is started by the operation of the cooling tower and ended by the stop as in the first embodiment. To do.

  In step S11, chemical injection control is performed. First, makeup water is supplied from the makeup water line 10 to the reservoir 6. And the control part 24 transmitted the drive signal to the medicinal pump 16a for every fixed time interval (for example, 30 minutes) so that the chemical | drug | medicine quantity proportional to the amount of replenishment water may be inject | poured, and it was stored by the medicinal device main body 16. The medicine is injected into the circulating water from the nozzle 17 with a predetermined pulse width.

  The amount of replenishment water when performing chemical injection control is calculated from the following formulas (1) and (2), and the evaporation loss amount E and the scattering loss amount W are calculated from the total value (E + W) of the evaporation loss amount E and the scattering loss amount W. presume.

E = R × (t1−t2) / λ (1)
W = R × 0.001 (2)
Here, R is the amount of circulating water (kg / h), t1 is the circulating water inlet temperature (° C.), t2 is the circulating water outlet temperature (° C.), and λ is the latent heat of vaporization (kcal / kg).

  For example, when the circulating water inlet temperature t1 is 30 ° C. and the circulating water outlet temperature t2 is 25 ° C., the evaporation loss amount E is about 0.1% of the circulating water amount R when the latent heat of vaporization of water is 580 kcal / kg (30 ° C.). 86%. Further, the scattering loss amount W is usually about 0.1% of the circulating water amount R.

  And based on this estimated amount of replenishment water, the time interval which transmits a drive signal to the chemical injection pump 16a, and the pulse width which inject | pours a chemical | medical agent are preset to the control part 24. FIG.

  Next, in step S12, it is determined whether or not blow control is to be started. If the answer is negative (No), the process returns to step S11. If the answer is affirmative (Yes), the process proceeds to step S13, the injection of the medicine is prohibited, the motor-operated valve 13 is opened, and the blow is performed. Execute. At the same time, the timer 28a ′ starts measuring the drainage period and stores it in the RAM 27.

  Next, in step S14, it is determined whether or not to end the blow control. If the answer is negative (No), the process waits for the blow control to end. If the answer is affirmative (Yes), the process proceeds to step S15, where the drainage period is stopped and the drainage period is calculated. In the subsequent step S16, the replenishment water amount in the drainage period is obtained by multiplying the time-lapse value of the drainage period by the set flow rate value of the constant flow valve 8, and the chemical amount corresponding to the replenishment water amount is calculated. In step S17, the amount of medicine calculated in step S16 is replenished and injected into the replenishing water. And after that, it returns to step S11 and performs the chemical injection control mentioned above. Note that the start and end of the blow control in steps S12 and S14 are determined based on the electrical conductivity detected by the electrical conductivity sensor 14, as in the first embodiment.

  FIG. 8 is a time chart showing the relationship between the chemical injection timing and the blow timing in the second embodiment, and as in the first embodiment (FIG. 4), the drainage period during which T2 performs the blow control. And T1 and T3 are non-drainage periods during which chemical injection control is performed without performing blow control.

  In the non-drainage periods T1 and T3, as shown in FIG. 8B, the medicine is injected into the circulating water at a predetermined time interval, for example, every 30 minutes, at a predetermined pulse width.

  Then, the concentration ratio of the circulating water increases with the passage of time and the electrical conductivity rises. As shown in FIG. 8A, when the electrical conductivity reaches the first predetermined value E1, FIG. ), The drainage period T2. In this drainage period T2, while injecting chemicals, makeup water is supplied from the forced water supply line 12 to the reservoir 6 to dilute the circulating water, and a part of the circulating water is blown from the blow pipe 7. On the other hand, when entering the drainage period T2, the timer 28a 'starts measuring time, and the drainage period T2 is calculated by the end of the blow. And by multiplying the drainage period T2 by the set flow rate value of the constant flow valve 8, the amount of makeup water in the drainage period T2 is calculated, the amount of medicine corresponding to the amount of makeup water is calculated, and after the drainage period T2 when blow control ends, A chemical amount corresponding to the replenishing water amount is collectively replenished and injected into the circulating water.

  As described above, in the second embodiment, the amount of makeup water during the drainage period T2 is calculated from the drainage period T2 and the set flow rate of makeup water, and the amount of medicine corresponding to the amount of makeup water is further calculated. Is replenished and injected into the replenishing water after the drainage period has elapsed, as in the first embodiment, the medicine just injected is not drained together with the blow water, so that the medicine is not wasted. In addition, the chemical concentration of the circulating water can always be maintained within an appropriate range.

  That is, also in the second embodiment, as in the first embodiment, the medicine injection and the blow control are linked and controlled so that the medicine injection and the blow control do not overlap in time, In addition, since the required amount of medicine is supplemented after blow control, it is possible to avoid wasteful consumption of the medicine while maintaining the medicine concentration at an appropriate concentration, and to optimize the amount of medicine used. Become.

  FIG. 9 is a flowchart showing the third embodiment, and shows another example of the operation control means in the cooling tower shown in FIG. In the third embodiment, steps S21 and S22 are added to the flowchart of FIG. 3 described in the first embodiment.

  That is, in the third embodiment, after performing the chemical injection control in step S1, it is determined in step S21 whether or not a predetermined period ΔT after chemical injection has elapsed. Here, the predetermined time ΔT can prevent the injected medicine from immediately flowing into the blow tube 7, and the concentration is excessive even if the electrical conductivity exceeds the first predetermined value E1 due to the delay of the blow timing. A predetermined time that is not promoted, for example, 30 minutes is set. If the answer is negative (No), i.e., immediately after drug injection, the process proceeds to step S22 to prohibit the blow control and wait for the predetermined time ΔT to elapse. And when predetermined time (DELTA) T passes after chemical injection, it will become a case where the answer of step S21 is affirmation (Yes), it progresses to step S2, and after that, the process similar to 1st Embodiment is performed.

  FIG. 10 is a time chart showing the relationship between the medicine injection timing and the blow timing in the third embodiment.

  In other words, the chemical injection control is performed in the non-drainage period T1, but after the chemical injection is performed, the blow is forcibly prohibited for a predetermined period ΔT, and the blow control is enabled after the predetermined period ΔT has elapsed. When the conductivity exceeds the first predetermined value E1, blow control is performed.

  As described above, in the third embodiment, the blow control is prohibited during the predetermined period ΔT after the drug injection, and then the blow control is enabled. Therefore, the injected medicine is immediately drained out of the system together with the circulating water. Can be prevented, and wasteful consumption of the medicine can be avoided.

  In addition, this invention is not limited to the said embodiment, It can apply not only to an open type cooling tower but to a closed type cooling tower.

  In the third embodiment, the blow control immediately after drug injection is prohibited with respect to the first embodiment, but the blow control immediately after drug injection is similarly applied to the second embodiment. It is also preferable to configure to prohibit.

It is a system configuration figure showing one embodiment (the 1st embodiment) of the operation control device of the cooling tower as a circulating water system concerning the present invention. It is a block block diagram of the said 1st Embodiment. It is a flowchart which shows 1st Embodiment of the control procedure of an operation control apparatus. It is a time chart of the said 1st Embodiment. It is a system block diagram which shows 2nd Embodiment of the operation control apparatus of a cooling tower. It is a block block diagram of the said 2nd Embodiment. It is a flowchart which shows 2nd Embodiment of the control procedure of an operation control apparatus. It is a time chart of the said 2nd Embodiment. It is a flowchart which shows 3rd Embodiment of the control procedure of an operation control apparatus. It is a time chart of the said 3rd Embodiment. It is a time chart of the operation control apparatus of the conventional circulating water system.

Explanation of symbols

1 Cooling tower (circulating water system)
7 Blow pipe (drainage means)
8 Constant flow valve (Constant flow control means)
11 Flow meter (flow rate detection means)
12 Forced water supply line (drainage means)
13 Motorized valve (drainage means)
14 Electric conductivity sensor (water quality detection means)
24 control unit (drug injection prohibiting means, replenishment water amount storage means, replenishment injection means, drainage period calculation means, drug amount calculation means, drainage prohibition means)

Claims (8)

A cooling tower that supplies the make-up water and cools the apparatus to be cooled directly or indirectly using the make-up water as circulating water, a medicine injection means for injecting the medicine into the circulating water, and detects the quality of the circulating water In a circulating water system operation control device comprising water quality detection means and drainage means for draining part of the circulating water to the outside according to the detection result of the water quality detection means,
During the drainage period in which a part of the circulating water is drained out of the system by the drainage means, a medicine injection prohibition means for prohibiting the injection of the medicine, a flow rate detection means for detecting the flow rate of the makeup water, and the flow rate detection means The replenishment water amount storage means for storing the replenishment water amount during the drainage period from the detection result of the replenishment, and the replenishment for replenishing and injecting into the circulating water the chemical amount corresponding to the replenishment water amount stored in the replenishment water amount storage means after the drainage period has elapsed An operation control device for a circulating water system comprising an injection means.   The circulating water system operation control device according to claim 1, wherein the makeup water amount storage means stores a count value of a flow rate pulse generated by the flow rate detection means. A cooling tower that supplies the make-up water and cools the apparatus to be cooled directly or indirectly using the make-up water as circulating water, a medicine injection means for injecting the medicine into the circulating water, and detects the quality of the circulating water In a circulating water system operation control device comprising water quality detection means and drainage means for draining a part of the circulating water out of the system according to the detection result of the water quality detection means,
A drainage period calculating means for calculating a drainage period for draining part of the circulating water to the outside by the drainage means; a drug injection prohibiting means for prohibiting the injection of the drug during the drainage period; and a flow rate of the makeup water. Calculated by the constant flow rate adjusting means for constant flow rate, the drug amount calculating means for calculating the drug amount based on the set flow rate of the constant flow rate setting means and the calculation result of the drainage period calculating means, and the drug amount calculating means A circulating water system operation control apparatus, comprising: a replenishing and injecting means for replenishing and injecting the amount of the medicine to the circulating water after the drainage period has elapsed.   2. A drainage prohibiting means for prohibiting drainage of the circulating water out of the system for a predetermined period after the drug is injected into the circulating water. The operation control apparatus of the circulating water system in any one of thru | or 3. Supplying make-up water to the cooling tower, cooling the device to be cooled directly or indirectly using the make-up water as circulating water, and injecting chemicals into the circulating water according to the quality of the circulating water In the operation method of the circulating water system that drains part of the circulating water outside the system,
During the drainage period in which a part of the circulating water is drained outside the system, the injection of the chemical is prohibited, the flow rate of the makeup water is detected, and the amount of makeup water during the drainage period is stored from the detection result, A circulating water system operating method, wherein after the drainage period has elapsed, a chemical amount corresponding to the stored makeup water amount is replenished and injected into the circulating water.   6. The circulating water system operation method according to claim 5, wherein a count value of a flow rate pulse is stored as the makeup water amount. Supplying make-up water to the cooling tower, cooling the device to be cooled directly or indirectly using the make-up water as circulating water, and injecting chemicals into the circulating water according to the quality of the circulating water In the operation method of the circulating water system that drains part of the circulating water outside the system,
During the drainage period during which a part of the circulating water is drained outside the system, the injection of the drug is prohibited, and the amount of the drug is calculated based on the set flow rate of the makeup water and the drainage period, and after the drainage period has elapsed A method for operating a circulating water system, wherein the chemical amount is replenished and injected into the circulating water.   8. When the medicine is injected into the circulating water, draining the circulating water outside the system is prohibited for a predetermined period after the injection of the medicine. To operate the circulating water system.

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