JP7556228B2 - Water treatment system management device - Google Patents

Description

The present invention relates to a management device for a water treatment system.

Conventionally, in cooling towers, poorly soluble salts dissolved in make-up water can become concentrated and exceed their solubility, resulting in the precipitation of scale inside the water tank that constitutes the cooling tower or on the filler contained in the cooling tower. In addition, depending on the temperature conditions of the circulating water, microorganisms can grow within the cooling tower system, causing slime and algae to form.

To prevent such problems, it is important to use chemicals such as scale dispersants and bactericides, and to properly control and manage the concentration of the circulating water. The concentration control (blow control) of the circulating water is carried out according to the electrical conductivity value measured by an electrical conductivity sensor installed in the circulating water line.

For example, Patent Document 1 discloses a technology that measures the electrical conductivity of cooling water and make-up water, calculates the concentration ratio of the cooling water using the measured values, and automatically calculates the concentration of water treatment chemicals.

Japanese Patent Application Publication No. 11-211386

Therefore, the electrical conductivity sensor is the key to controlling concentration, but if scale, slime or other contaminants adhere to the surfaces of the two exposed electrodes of a general-purpose two-electrode electrical conductivity sensor, the sensitivity of the electrical conductivity sensor may decrease. In this case, the electrical conductivity sensor will indicate a value lower than the true electrical conductivity of the actual circulating water, which may result in the circulating water becoming over-concentrated, creating a vicious cycle that can lead to problems related to the generation of scale, slime, and the like.

One possible method to use this method is to control concentration using a four-electrode or electrodeless (electromagnetic induction) electrical conductivity sensor, which are generally considered to be resistant to fouling. Another possible method is to add an electrical conductivity sensor that is resistant to fouling, compare the measured value with the measured value of a general-purpose electrical conductivity sensor as the true value of the actual electrical conductivity of the circulating water, and if the difference between the true value and the measured value becomes large, determine that the general-purpose electrical conductivity sensor has become fouled and perform cleaning. However, there are issues such as cost, and it may be difficult to implement these methods in small to medium-sized cooling towers.

As a result, when regular maintenance is performed at the cooling tower installation site, the dirt status of the electrical conductivity sensor is checked each time, and if dirt is found, it is dealt with by cleaning. As a result, there is no planned maintenance response or optimization of the timing of visits to the cooling tower installation site when the electrical conductivity sensor becomes dirty.

The present invention aims to provide a management device that can determine the degree of dirt adhesion on a single electrical conductivity sensor by using the electrical conductivity sensor.

The present invention relates to a management device for a water treatment system having a cooling tower that cools circulating water supplied to a cooled device and returned from the cooled device, a circulating water line that circulates the circulating water between the cooling tower and the cooled device, and a make-up water line that supplies make-up water to the cooling tower, and the management device is equipped with make-up water amount detection means that is installed in the make-up water line and detects the amount of the make-up water, an electrical conductivity detection means that is installed in the circulating water line and detects the electrical conductivity of the circulating water, and a contamination determination means that determines the degree of contamination on the electrical conductivity detection means based on the amount of the make-up water and the amount of change in the detected value of the electrical conductivity.

In addition, in the above-mentioned management device, it is preferable that the contamination determination means determines the contamination adhesion state based on the rate of increase in the electrical conductivity while a predetermined amount of makeup water is supplied to the cooling tower.

In the above-mentioned management device, the make-up water line is provided with an automatic make-up water line that automatically supplies make-up water to the cooling tower mainly depending on the amount of evaporated water, a forced make-up water line that forcibly supplies make-up water to the cooling tower during blow control, and a blow control valve that is installed on the forced make-up water line and opens and closes based on the electrical conductivity, and the contamination determination means preferably determines the contamination adhesion state based on the number of times the blow control valve is opened and closed while a predetermined amount of make-up water is supplied to the cooling tower.

According to the present invention, it is possible to provide a management device that can determine the state of dirt adhesion on a single electrical conductivity sensor by using the electrical conductivity sensor.

1 is an overall configuration diagram of a water treatment system 1 according to a first embodiment of the present invention. 1 is a functional block diagram relating to control included in a water treatment system 1 according to a first embodiment of the present invention. FIG. 4 is a graph showing time series changes in the measured values of each electrical conductivity sensor in the simulator for the water treatment system according to the first embodiment of the present invention. 4 is a table showing time series changes in measured values of each electrical conductivity sensor in the simulator for the water treatment system according to the first embodiment of the present invention. FIG. 11 is a functional block diagram relating to control included in a water treatment system 1A according to a second embodiment of the present invention.

1. First Embodiment
A first embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a water treatment system to which a management device according to the present invention is applied will be described. FIG. 1 is a schematic configuration diagram showing a water treatment system 1 of this embodiment. FIG. 2 is a functional block diagram related to control included in the water treatment system shown in FIG. 1. FIG. 3A is a graph showing time series changes in measured values of each electrical conductivity sensor in a simulator of a water treatment system according to this embodiment. FIG. 3B is a table showing time series changes in measured values of each electrical conductivity sensor in a simulator of a water treatment system according to this embodiment.

1.1 Overall configuration of the first embodiment
As shown in Fig. 1, the water treatment system 1 of this embodiment is a system that circulates circulating water W2 (cooling water) to cool a cooled device 131, such as a heat exchanger incorporated in an air conditioner or a refrigerator. During operation of the water treatment system 1, the circulating water W2 is used while being circulated while being cooled in a cooling tower 120. The circulating water W2 is replenished from the outside when it is reduced due to evaporation, scattering, blowdown processing (described later), and the like. In this embodiment, the cooling tower 120 as an industrial facility is a so-called open-type cooling tower.

The water treatment system 1 of this embodiment mainly comprises a cooling tower 120, a cooled device 131, an electrical conductivity sensor (hereinafter also referred to as an "EC sensor") 133, a flow sensor 135, a system control unit 100, and a management unit 200. The water treatment system 1 also comprises, as main lines, a circulating water line L110, a make-up water line L120, and a drainage line L130. "Line" is a general term for a line through which a fluid can flow, such as a flow path, a route, or a pipeline.

The cooling tower 120 is a facility that receives makeup water W1, supplies this makeup water W1 to the cooled device 131 as circulating water W2, and cools the circulating water W2 recovered (returned) from the cooled device 131. The cooling tower 120 includes a tower body 121 and a storage section 122. The cooling tower 120 and the circulating water line L110 constitute a circulating water system. That is, in this embodiment, the circulating water W2 includes the water stored in the cooling tower 120 and the water flowing through the circulating water line L110, and refers to the water used as cooling water to cool the cooled device 131.

The tower body 121 is a housing that forms the outer shell of the cooling tower 120. The tower body 121 has a circulating water cooling section (not shown) that consists of a water spray section, a fan, an opening, louvers, a filler, etc. The circulating water W2 is cooled by the circulating water cooling section and falls into the storage section 122.

The storage section 122 is a section for storing the circulating water W2 cooled in the circulating water cooling section. The storage section 122 is provided at the bottom of the tower body 121. The circulating water supply line L111 (described later) of the circulating water line L110 is connected to the bottom of the storage section 122. The circulating water W2 stored in the storage section 122 is supplied to the cooled device 131 via the circulating water supply line L111. The storage section 122 is provided with a water supply valve 137 and an overflow port 138 used in the blowdown process.

The circulating water line L110 is a line that circulates the circulating water W2 between the cooling tower 120 and the cooled device 131. The circulating water line L110 has a circulating water supply line L111 and a circulating water recovery line L112.

A circulating water pump 132 and an electrical conductivity sensor 133 are provided in the circulating water supply line L111.

The circulating water pump 132 can pump circulating water W2 from the upstream side to the downstream side of the circulating water line L110 (circulating water supply line L111, circulating water recovery line L112). The operation of the circulating water pump 132 is performed within the operation control of the cooling tower 120 and the cooled device 131 described below. The circulating water pump 132 is electrically connected to the system control unit 100. Therefore, the operation signal of the circulating water pump 132 can be acquired by the system control unit 100.

The electrical conductivity sensor 133 is a device that measures the water quality of the circulating water W2 flowing through the circulating water supply line L111 and outputs the water quality as a detected electrical conductivity value. The electrical conductivity sensor 133 is electrically connected to the system control unit 100. The detected electrical conductivity value measured by the electrical conductivity sensor 133 is transmitted to the system control unit 100. The electrical conductivity sensor 133 measures the electrical conductivity of the circulating water W2 in real time and transmits the electrical conductivity to the system control unit 100.

The circulating water recovery line L112 is a line that connects the cooled device 131 and the tower body 121. The circulating water W2 that is heated by heat exchange in the cooled device 131 is recovered in the circulating water cooling section (not shown) of the tower body 121 via the circulating water recovery line L112.

The cooled equipment 131 is various equipment such as a heat exchanger that requires cooling with circulating water W2. The cooled equipment 131 is cooled using circulating water W2 cooled in a cooling tower 120. The cooled equipment 131 is, for example, a turbo refrigerator or absorption refrigerator in various chemical plants, a cooling machine for air conditioning in a building, a cold water maker or a vacuum cooling machine in a food factory, etc.

In the cooled device 131, one end of the circulating water flow path is connected to the downstream end of the circulating water supply line L111. In addition, in the cooled device 131, the other end of the circulating water flow path is connected to the upstream end of the circulating water recovery line L112.

A make-up water line L120 is connected to the cooling tower 120. The make-up water line L120 is a line that supplies make-up water W1 to the storage section 122 (circulating water system). The make-up water line L120 has a first make-up water line L121 on the upstream side, and a second make-up water line L122 and a third make-up water line L123 on the downstream side. The first make-up water line L121 is connected to a supply source (not shown) of make-up water W1 such as tap water or industrial water. The make-up water line L120 branches into a second make-up water line L122 and a third make-up water line L123 at a branch point J1. Hereinafter, the second make-up water line L122 may be referred to as a "forced make-up water line" and the third make-up water line L123 may be referred to as an "automatic make-up water line."

A flow sensor 135 is connected to the first make-up water line L121 as a flow rate detection means. The flow sensor 135 is a device that detects the flow rate per unit time of the make-up water W1 flowing through the first make-up water line L121. As the flow sensor 135, for example, a pulse-emitting flow sensor having an axial or tangential impeller (not shown) arranged in a flow path housing can be used.

The pulse-emitting flow sensor used in this embodiment has an impeller with an even number of blades whose tips are alternately magnetized with north and south poles. The pulse-emitting flow sensor detects the rotation of the impeller with a Hall IC, and outputs a pulse signal with a duration proportional to the flow rate of the make-up water W1. The Hall IC is an electronic circuit that packages a voltage regulator, a Hall element, an amplifier circuit, a Schmitt trigger circuit, an output transistor, etc. This electronic circuit responds to the change in magnetic flux accompanying the rotational motion of the impeller, and outputs a square wave pulse signal as a detected water volume value for each rotation of the impeller. The flow rate [L/pulse] when the impeller rotates once is determined by the design specifications of the flow sensor.

For example, in the flow rate sensor 135, if the flow rate when the impeller rotates once is 1 [L], and the number of pulse signals output from the flow rate sensor 135 is 3 pulses, the amount of make-up water W1 is 3 [L].

The downstream end of the second make-up water line L122 is connected to the tower body 121. In the second make-up water line L122, a make-up water valve 136 is provided between the branch J1 and the cooling tower 120. Examples of the type of make-up water valve 136 include a solenoid-driven electromagnetic valve, a motor-driven electric valve, and a compressed air-driven valve.

The makeup water valve 136 can open and close the second makeup water line L122. By opening the second makeup water line L122, makeup water W1 can be forcibly supplied to the storage section 122. The makeup water valve 136 is electrically connected to the system control unit 100. The open/close state of the makeup water valve 136 is controlled by a valve drive signal output from the system control unit 100. By opening the makeup water valve 136, the second makeup water line L122 can be opened. By closing the makeup water valve 136, the second makeup water line L122 can be closed. In the following, the makeup water valve 136 is also referred to as the "blow control valve 136."

The downstream end of the third make-up water line L123 is connected to the tower body 121. A water supply valve 137 is provided at the downstream end of the third make-up water line L123. The water supply valve 137 is a ball tap type water supply device that manages the water level (i.e., water volume) of the circulating water W2 in the storage section 122. When the water level of the storage section 122 drops due to evaporation and scattering of the circulating water W2, the ball tap of the water supply valve 137 is activated and the make-up water W1 flowing through the third make-up water line L123 is replenished to the storage section 122.

The drain line L130 is attached so as to extend in a substantially vertical direction inside the storage section 122. The drain line L130 extends further downward from the storage section 122. The upstream end of the drain line L130 forms an overflow port 138 for the circulating water W2. The overflow port 138 opens above the controlled water level of the water supply valve 137. Meanwhile, the downstream end of the drain line L130 leads to the outside of the storage section 122. The drain line L130 is a line that discharges the circulating water W2 that overflows from the storage section 122 to the outside of the system when the makeup water valve 136 is opened during the blowdown process and makeup water W1 is forcibly supplied.

In the above configuration, by opening the makeup water valve 136, a blowdown process can be performed in which makeup water W1 is replenished to the cooling tower 120 while a portion of the circulating water W2 is discharged from the cooling tower 120 to the outside. The makeup water valve 136 is controlled to an open state when the quality of the circulating water W2 deteriorates, and functions as a blowing means for forcibly replenishing fresh makeup water W1 to the storage section 122 through the second makeup water line L122 while discharging a portion of the circulating water W2 stored in the storage section 122 from the drain line L130 to the outside.

In addition, in the above configuration, the electrical conductivity sensor 133 is installed in the circulating water supply line L111, but this is just one example and is not limited to this.

1.2 Control of water treatment system 1
Next, functions relating to the control of the water treatment system 1 will be described with reference to FIG.

The system control unit 100 controls the operation of each part in the water treatment system 1. As shown in FIG. 3, the system control unit 100 is electrically connected to, for example, the make-up water valve 136.

The system control unit 100 is also electrically connected to each measuring device in the water treatment system 1 and receives measurement information from these measuring devices. For example, the system control unit 100 is electrically connected to an electrical conductivity sensor 133 and a flow rate sensor 135 as measuring devices. In the system control unit 100, the latest measurement information received from each measuring device is appropriately stored in a memory 230 provided in the management unit 200 described below.

The system control unit 100 includes a blow control unit 110. The functions of the blow control unit 110 in the system control unit 100 are realized by a microprocessor (not shown) including a CPU and internal memory.

When the electrical conductivity detected by the electrical conductivity sensor 133 reaches a preset upper threshold, the blow control unit 110 opens the make-up water valve 136 to execute the blow-down process, and when the electrical conductivity detected by the electrical conductivity sensor 133 reaches a preset lower threshold, the blow control unit 110 closes the make-up water valve 136 to terminate the blow-down process.

The management unit 200 determines the degree of contamination of the electrical conductivity sensor 133 based on the flow rate of makeup water W1 and the rate of increase in the detected electrical conductivity of circulating water W2 in the water treatment system 1. The management unit 200 can communicate with the system control unit 100, and can thereby obtain the detected values of the electrical conductivity sensor 133 and the flow rate sensor 135 via the system control unit 100. The management unit 200 may be provided on the cloud. The system control unit 100 and the management unit 200 may be configured as separate entities, or may be configured to be provided in the same housing.

The management unit 200 includes a dirt determination unit 210, an alarm unit 220, and a memory 230. The functions of the dirt determination unit 210 and the alarm unit 220 in the management unit 200 are realized by a microprocessor (not shown) including a CPU and internal memory.

The contamination determination unit 210 determines the degree of contamination on the electrical conductivity sensor 133 based on the flow rate of the make-up water W1 detected by the flow rate sensor 135 and the amount of change in the detected value of the electrical conductivity of the circulating water W2 detected by the electrical conductivity sensor 133.

More specifically, the contamination determination unit 210 determines the contamination status of the electrical conductivity sensor 133 based on the rate of increase in the detected electrical conductivity while a predetermined amount of makeup water W1 is supplied to the cooling tower 120. Specifically, the contamination determination unit 210 may determine that a predetermined amount or more of contamination is attached to the electrical conductivity sensor 133 when the rate of increase in electrical conductivity while a predetermined amount of makeup water W1 is supplied to the cooling tower 120 falls below the rate of increase in electrical conductivity while a predetermined amount of makeup water W1 is supplied to the cooling tower 120 in the immediately preceding term.

The above "amount of change in the detected value of electrical conductivity" and "rate of increase in the detected value of electrical conductivity" may be the amount of change or rate of increase relative to the reference value calculated every predetermined period, with the value of electrical conductivity at the start of operation of the water treatment system 1 as a reference value. The contamination determination unit 210 may also determine contamination based on the relationship between the flow rate of the make-up water W1 and the electrical conductivity for the first one or more terms that serve as a reference. Furthermore, the relationship between the flow rate of the make-up water W1 and the electrical conductivity for the first one or more terms that serve as a reference may be updated at predetermined intervals, for example every time maintenance is performed on the water treatment system 1.

The alarm unit 220 issues an alarm when the dirt determination unit 210 determines that a predetermined amount or more of dirt is attached to the electrical conductivity sensor 133.

Since the system control unit 100 and the management unit 200 have the above configuration, the contamination determination unit 210 determines the contamination adhesion state on the electrical conductivity sensor 133 based on the flow rate of the make-up water W1 and the amount of change in the detected value of the electrical conductivity of the circulating water W2, and if a predetermined amount or more of contamination is attached to the electrical conductivity sensor 133, the alarm unit 220 issues an alarm.

1.3 Experimental Data
By using an apparatus simulating the water treatment system 1 according to this embodiment, an experiment was conducted to investigate the relationship between the amount of dirt adhering to an electrical conductivity sensor and the change over time in the electrical conductivity value detected by the electrical conductivity sensor.

More specifically, a device was created in which circulating water is sent from a water tank to a thermostatic tank via a pump, and the circulating water heated in the thermostatic tank falls from top to bottom through a pipe and returns to the water tank, with part of the circulating water being concentrated by outside air drawn in by a fan. In addition, in this device, Matsuyama City tap water is used as make-up water, and the necessary amount of make-up water is replenished to the water tank so that the amount of water in the tank does not decrease. Furthermore, by using a new electrical conductivity sensor, an electrical conductivity sensor with a little dirt attached, and an electrical conductivity sensor with a lot of dirt attached as electrical conductivity sensors to detect the electrical conductivity of the circulating water, the change over time in the electrical conductivity of the circulating water as a concentration behavior was obtained.

Figure 3A shows, from top to bottom, the change over time in electrical conductivity detected using a new electrical conductivity sensor, a slightly dirty electrical conductivity sensor, and a heavily dirty electrical conductivity sensor. Figure 3B also shows the electrical conductivity value at each time and the increase in electrical conductivity detected by each electrical conductivity sensor.

As shown in the graph in Figure 3A, the electrical conductivity value detected by the electrical conductivity sensor with a lot of dirt attached was significantly smaller than the electrical conductivity value detected by the other electrical conductivity sensors. This is thought to be because the dirt, such as scale, attached to the electrical conductivity sensor acts as resistance, reducing the sensitivity of the electrical conductivity sensor. Therefore, at the point where the arrow in Figure 3A starts, the dirt was cleaned from the electrical conductivity sensor with a lot of dirt attached using a 5 wt% NaOH solution at 60°C and a 3 wt% citric acid solution at 60°C.

As a result, as shown after the end of the arrow in the graph of FIG. 3A, the electrical conductivity value detected by the electrical conductivity sensor that was heavily soiled was comparable to the electrical conductivity values detected by the other electrical conductivity sensors. This is also shown in the numerical values in the "EC value at each time" column in the table of FIG. 3B. Also, as shown in the numerical values in the "EC increase" column in the table of FIG. 3B, the increase in electrical conductivity after cleaning the dirt from the electrical conductivity sensor that was heavily soiled was the same as that of a new electrical conductivity sensor.

1.4 Advantages of the First Embodiment
According to the management device of the water treatment system 1 according to the present embodiment described above, for example, the following effects can be obtained.

The management device for the water treatment system 1 according to this embodiment is a management device for the water treatment system 1 having a cooling tower 120 that cools the circulating water W21 that is supplied to the cooled device 131 and returned from the cooled device 131, a circulating water line L110 that circulates the circulating water W2 between the cooling tower 120 and the cooled device 131, and a make-up water line L120 that supplies make-up water to the cooling tower 120. The management device is equipped with a flow rate sensor 135 that is installed on the make-up water line L120 and detects the amount of make-up water W1, an electrical conductivity sensor 133 that is installed on the circulating water line L110 and detects the electrical conductivity of the circulating water W2, and a contamination determination unit 210 that determines the degree of contamination on the electrical conductivity sensor 133 based on the amount of make-up water and the amount of change in the detected value of electrical conductivity.

The present invention makes it possible to determine the degree of dirt adhesion using a single electrical conductivity sensor, without using an expensive electrical conductivity sensor or multiple electrical conductivity sensors. Furthermore, by remotely monitoring the measured values of the electrical conductivity sensor and providing an opportunity for cleaning maintenance only when the electrical conductivity sensor becomes dirty, it becomes possible to reduce the frequency of regular maintenance and cut personnel costs. Furthermore, it becomes possible to suppress problems caused by overconcentration of circulating water due to adhesion of dirt to the electrical conductivity sensor.

In addition, in the above-mentioned management device, the contamination determination unit 210 determines the contamination adhesion state based on the rate of increase in electrical conductivity while a predetermined amount of makeup water W1 is supplied to the cooling tower 120.

A sensor with a lot of dirt attached to it will have a lower rate of increase in electrical conductivity while a specified amount of makeup water is being supplied, due to a decrease in sensitivity caused by the adhesion of dirt. Therefore, the dirt determination means is configured to determine the dirt adhesion state based on the rate of increase in electrical conductivity while a specified amount of makeup water is being supplied to the cooling tower. This makes it possible to determine the dirt adhesion state using the rate of increase in electrical conductivity while a specified amount of makeup water is being supplied as the determination criterion. Therefore, even when a single electrical conductivity sensor is used, it is possible to determine the dirt adhesion state of the electrical conductivity sensor.

2. Second embodiment
A second embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a water treatment system to which a management device according to the present invention is applied will be described. Note that the overall configuration of the water treatment system 1A of this embodiment is basically the same as that of the water treatment system 1 of the first embodiment, and therefore a description thereof will be omitted. Fig. 4 is a functional block diagram relating to control included in the water treatment system 1A according to this embodiment.

2.1 Control of Water Treatment System 1A
Functions related to the control of the water treatment system 1A will be described with reference to Fig. 4. The water treatment system 1 includes a management unit 200A instead of the management unit 200 included in the water treatment system 1. Fig. 4 is a functional block diagram of the system control unit 100 and the management unit 200A. As shown in Fig. 4, the management unit 200A includes a contamination determination unit 210A instead of the contamination determination unit 210 included in the management unit 200.

The contamination determination unit 210A determines the contamination state based on the number of times the makeup water valve 136 is opened and closed while a predetermined amount of makeup water W1 is supplied to the cooling tower 120. More specifically, the contamination determination unit 210A determines that a predetermined amount or more of contamination is attached to the electrical conductivity sensor 133 when the number of times the makeup water valve 136 is opened and closed while a predetermined amount of makeup water W1 is supplied to the cooling tower 120 is lower than the number of times the makeup water valve 136 is opened and closed while a predetermined amount of makeup water W1 is supplied to the cooling tower 120 in the immediately preceding term.

The alarm unit 220 issues an alarm when the contamination determination unit 210A determines that a predetermined amount or more of contamination is attached to the electrical conductivity sensor 133.

As the management unit 200A has the above-mentioned configuration, the contamination determination unit 210A determines the contamination adhesion state of the electrical conductivity sensor 133 based on the number of times the makeup water valve 136 is opened and closed while a predetermined amount of makeup water W1 is supplied to the cooling tower 120, and if a predetermined amount or more of contamination is attached to the electrical conductivity sensor 133, the alarm unit 220 issues an alarm.

2.2 Advantages of the Second Embodiment
According to the management device of the water treatment system 1A according to the present embodiment described above, for example, the following effects can be obtained.

In the water treatment system 1A according to this embodiment, the make-up water line L120 includes a third make-up water line L123 that automatically supplies make-up water to the cooling tower 120, a second make-up water line L122 that forcibly supplies make-up water to the cooling tower 120 during blow control, and a make-up water valve 136 that is installed on the second make-up water line L122 and opens and closes based on electrical conductivity, and the contamination determination unit 210A determines the contamination adhesion state based on the number of times the make-up water valve 136 is opened and closed while a predetermined amount of make-up water W1 is supplied to the cooling tower 120.

When dirt adheres to the electrical conductivity sensor, the rate of increase in the measured electrical conductivity slows as the circulating water becomes concentrated, and it takes longer to reach the upper limit set value for electrical conductivity during blow control, which reduces the number of times the blow control valve operates while a predetermined amount of makeup water is supplied. Therefore, the dirt determination means determines the dirt adhesion state based on the number of times the blow control valve operates while a predetermined amount of makeup water is supplied to the cooling tower. This makes it possible to determine the dirt adhesion state using the number of times the blow control valve opens and closes while a predetermined amount of makeup water is supplied as the determination criterion. Therefore, even when a single electrical conductivity sensor is used, the dirt adhesion state of the electrical conductivity sensor can be determined.

[3 Modifications]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. Furthermore, the effects described in the present embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiment.

For example, an electrical conductivity sensor may be provided not only in the circulating water line L110 but also in the make-up water line L120, and the electrical conductivity of the make-up water W1 may also be used to determine the contamination status of the electrical conductivity sensor 133. In this way, when the electrical conductivity of the make-up water W1 changes significantly, the contamination determination unit 210 or 210A can determine the contamination status of the electrical conductivity sensor 133 based on this change. In particular, in the first embodiment, the contamination status is determined based on the decrease in the rate of increase in the electrical conductivity of the circulating water W2 while a predetermined amount of make-up water W1 is supplied to the cooling tower 120. However, when the electrical conductivity of the make-up water W1 decreases significantly, even if the rate of increase in the electrical conductivity of the circulating water W2 decreases, the decrease in the electrical conductivity of the make-up water W1 is taken into account to make an appropriate contamination determination.

1 Water treatment system 100 System control unit 110 Blow control unit 120 Cooling tower 121 Tower body 122 Storage unit 131 Cooled device 132 Circulating water pump 133 Electrical conductivity sensor 135 Flow rate sensor 136 Make-up water valve 137 Water supply tap 138 Overflow port 210, 210A Contamination determination unit 220 Alarm unit 230 Storage unit (memory)

Claims (3)

A cooling tower that cools circulating water supplied to the cooled device and returned from the cooled device;
A circulating water line for circulating circulating water between the cooling tower and the cooled device;
A make-up water line for supplying make-up water to the cooling tower,
A make-up water amount detection means is provided on the make-up water line and detects the amount of the make-up water.
an electrical conductivity detection means installed on the circulating water line and detecting the electrical conductivity of the circulating water;
a contamination determination means for determining a degree of contamination on the electrical conductivity detection means based on the amount of the makeup water and the amount of change in the detected value of the electrical conductivity. The management device according to claim 1, wherein the contamination determination means determines the contamination adhesion state based on the rate of increase in the electrical conductivity while a predetermined amount of makeup water is supplied to the cooling tower. A cooling tower that cools circulating water supplied to the cooled device and returned from the cooled device;
A circulating water line for circulating circulating water between the cooling tower and the cooled device;
A make-up water line for supplying make-up water to the cooling tower;
A make-up water amount detection means is provided on the make-up water line and detects the amount of the make-up water.
An electrical conductivity detection means is installed in the circulating water line and detects the electrical conductivity of the circulating water.
The make-up water line further comprises:
an automatic water supply line for automatically supplying makeup water to the cooling tower;
A forced water supply line for forcibly supplying makeup water to the cooling tower during blow control;
A blow control valve is provided in the forced water replenishment line and is opened and closed based on the electrical conductivity.
and a contamination determination means for determining a contamination adhesion state of the electrical conductivity detection means when contamination of the electrical conductivity detection means is progressing based on a decrease in the number of times the blow control valve is opened and closed while a predetermined amount of makeup water is supplied to the cooling tower .

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