JP2021081101A - Abnormality symptom detection device - Google Patents

Abstract

To provide an abnormality symptom detection device capable of preventing occurrence of clogging in a condenser by accurately detecting symptom of the occurrence of clogging in the condenser.SOLUTION: An abnormality symptom detection device includes: a storage unit 3 for setting a clogging state of a condenser 21 in advance, determining a maximum discharge pressure in a unit time of the condenser 21 corresponding to the set clogging state, determining a reference threshold value D1 of the maximum discharge pressure of the condenser 21 in which the clogging state occurs on the basis of the maximum discharge pressure, and storing the reference threshold value D1; a pressure sensor P detecting a discharge pressure of the condenser 21; and a clogging determination unit 5 for determining the symptom or occurrence of the clogging of the condenser 21 on the basis of the number of times when the maximum discharge pressure in the unit time detected by the pressure sensor P, becomes the reference threshold value D1 or more within a prescribed period.SELECTED DRAWING: Figure 1

Description

The present invention relates to an abnormal sign detection device capable of accurately detecting signs of clogging of a condenser and preventing clogging of a condenser.

Generally, in the condenser of a refrigerator, an abnormality is detected by the air volume of the fan of the condenser or the like. When an abnormality in the condenser is detected, the controller issues an alarm to operate a protection circuit such as a high-voltage cutoff device.

Here, clogging is one of the causes of abnormalities in the condenser. In Patent Document 1, the difference between the outside air temperature and the high-pressure saturation temperature is calculated, and the clogging of the condenser is determined using a preset threshold value. doing.

Japanese Patent No. 6440815

However, Patent Document 1 does not detect a sign that the condenser is clogged. Detecting the occurrence of clogging of the condenser has already significantly reduced the cooling performance, and in the detection of clogging, improper temperature control of the product to be cooled causes product loss, etc. And shorten the life of the cooling system including the condenser.

The sign of clogging of the condenser can be detected by, for example, the discharge pressure of the condenser, but the sign of clogging cannot be detected accurately even by using the average value of the discharge pressure. .. For example, in cold equipment, there are various operating conditions such as defrosting of a showcase, pressure control of a refrigerator, and oil return operation, and the discharge pressure fluctuates greatly depending on these operating conditions. In addition, the refrigerator is not always operated at 100% capacity, but the operating frequency is made variable by inverter control according to the outside air temperature, outside air humidity, and freezing addition to save energy. , The discharge pressure fluctuates greatly. As described above, since the discharge pressure fluctuates greatly depending on various operating conditions of the cooling system, it is difficult to determine a sign of clogging of the condenser even by simply measuring the discharge pressure. That is, it was difficult to determine the threshold value for determining the sign of clogging of the condenser.

The present invention has been made in view of the above, and an abnormal sign detection device capable of accurately detecting signs of clogging of a condenser and preventing clogging of a condenser can be prevented. The purpose is to provide.

In order to solve the above-mentioned problems and achieve the object, the present invention presents an abnormality of the condenser in a cooling system in which the cooler exchanges heat with the cooling space by a refrigerant circulating through a refrigerator including a condenser. This is an abnormal sign detection device that detects the above, and the clogging state of the condenser is set in advance, the maximum discharge pressure of the condenser corresponding to the set clogging state in a unit time is obtained, and the maximum discharge pressure is also obtained. A reference threshold for the maximum discharge pressure of the condenser in which the clogging state occurs is obtained, a storage unit for storing the reference threshold, a pressure sensor for detecting the discharge pressure of the condenser, and within a predetermined period of time. It is characterized by including a clogging determination unit that determines a sign or occurrence of clogging of the condenser based on the number of times that the maximum discharge pressure in a unit time detected by the pressure sensor becomes equal to or higher than the reference threshold value. And.

Further, in the above invention, the present invention includes an outside air temperature sensor that detects the outside air temperature, and the maximum discharge pressure in a unit time of the condenser is two-dimensional information with the outside air temperature detected by the outside air temperature sensor as a parameter. The reference threshold is a characteristic curve that approximates the relationship between the maximum discharge pressure and the outside air temperature.

Further, in the above invention, in the above invention, the clogging state is a stepwise plurality of clogging states, and the reference threshold value is obtained for each of the stepwise plurality of clogging states. The clogging determination unit is characterized in that, based on the plurality of reference threshold values, a plurality of corresponding stepwise clogging states are detected to determine a sign or occurrence of clogging of the condenser. To do.

Further, the present invention is characterized in that, in the above invention, the clogging determination unit outputs a sign or occurrence of clogging of the condenser to the output unit.

Further, in the above invention, the present invention is provided with a temperature sensor for detecting the discharge temperature of the condenser, and the maximum discharge temperature of the condenser is used instead of the maximum discharge pressure of the condenser. It is characterized by determining a sign of clogging.

According to the present invention, it is possible to accurately detect the sign of clogging of the condenser and prevent the clogging of the condenser from occurring.

FIG. 1 is a block diagram showing a configuration of a cooling system including a controller having a function of an abnormality sign detecting device according to an embodiment of the present invention, a pressure sensor, and a temperature sensor. FIG. 2 is a diagram showing the dependence of the maximum discharge pressure in a unit time on the outside air temperature for explaining the determination of the reference threshold value. FIG. 3 is a flowchart showing a clogging determination processing procedure by the clogging determination unit 5. FIG. 4 is a diagram showing an example of the number of times of the maximum discharge pressure generated in regions where the clogging state is different. FIG. 5 is a diagram showing a display example in which the data shown in FIG. 4 is graphically displayed. FIG. 6 is a block diagram showing a configuration of a cooling system having a function of an abnormality sign detection device, which is a modification 2 of the embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the following embodiment, an abnormality sign detection device for a cooling system for cooling the prefabricated showcase 10 installed in a store such as a convenience store or a supermarket will be described as an example.

<Device configuration>
FIG. 1 is a block diagram showing a configuration of a cooling system including a controller 1, a pressure sensor P, and a temperature sensor Ta having a function of an abnormality sign detecting device according to an embodiment of the present invention. The abnormality sign detection device detects signs of clogging of the condenser 21.

As shown in FIG. 1, the cooling system includes a controller 1, a controller 1 in the store 100, a prefabricated showcase 10 in the store 100, a refrigerator 20 outside the store 100, and a temperature sensor Ta outside the store 100. Is connected via network N. Inside the prefabricated showcase 10, a cooler 12 and an expander 11 which are heat exchangers for cooling the products and the like in the prefabricated showcase 10 are provided. The cooler 12 is, for example, an evaporator. Further, in the refrigerator 20, a compressor, a condenser 21, and a pressure sensor P for detecting the discharge pressure of the condenser 21 are provided. The temperature sensor Ta detects the outside air temperature.

The cooler 12 and the expander 11 are connected to the refrigerator 20 outside the store 100 via the pipe L. The refrigerator 20 includes a compressor and a condenser 21 which is a heat exchanger. Then, the compressor, the condenser 21, the expander 11, and the cooler 12 form a refrigeration cycle in which the refrigerant circulates through the pipe L.

The controller 1 has an input / output unit 2, a storage unit 3, and a control unit 4. The input / output unit 2 is an input / output device such as a touch panel, which inputs various setting information for the cooling system and outputs various data such as a control state and a control result of the cooling system. In particular, the input / output unit 2 sets the reference threshold value D1 described later in the storage unit 3 and outputs a sign or occurrence of clogging of the condenser 21.

The storage unit 3 is a storage device composed of a non-volatile memory such as a flash memory or a secondary storage medium such as a hard disk device, and stores the above-mentioned reference threshold value D1. Although the details will be described later, the reference threshold value D1 is set in advance for the condenser 21 or a condenser having the same specifications as the condenser 21, and the unit time of the condenser 21 corresponding to the set clogging state. For example, the maximum discharge pressure in one hour is obtained, and the maximum discharge pressure of the condenser 21 at which a clogging state occurs is determined based on this maximum discharge pressure.

The control unit 4 is a control unit that controls the entire controller, and has a clogging determination unit 5. The control unit 4 stores the programs corresponding to the clogging determination unit 5 in a storage device such as a non-volatile memory or a magnetic disk device, loads these programs into the memory, and executes the programs on the CPU. Will run the process.

The clogging determination unit 5 of the condenser 21 is based on the number of times that the maximum discharge pressure in a unit time (for example, 1 hour) detected by the pressure sensor P becomes equal to or higher than the reference threshold value D1 within a predetermined period, for example, one day. Determine signs or occurrence of clogging. Further, when the clogging determination unit 5 determines that there is a sign or occurrence of clogging, the clogging determination unit 5 outputs an alarm to an external output unit via the input / output unit 2 or the network N.

In the present embodiment, since the maximum discharge pressure has an outside air temperature dependence, the reference threshold value D1 is a characteristic curve that approximates the relationship of the maximum discharge pressure with respect to the outside air temperature. FIG. 2 is a diagram showing a specific example of the reference threshold value D1.

In FIG. 2, the maximum discharge output per unit time and the outside air at that time are set in advance when the condenser 21 is set to 30% for clogging, 50% for clogging, and 70% for clogging when there is no clogging. Two-dimensional information with temperature is plotted on the coordinates of the maximum discharge output per unit time and the outside air temperature. Then, a characteristic curve that approximates the relationship of the maximum discharge pressure with respect to the outside air temperature is calculated for each plot group of 30% clogging, 50% clogging, and 70% clogging under normal conditions without clogging. In FIG. 2, each characteristic curve is approximated as an approximate straight line, and a normal reference threshold value D0, a reference threshold value D1 with a clogging of 30%, a reference threshold value D2 with a clogging of 50%, and a reference threshold value D3 with a clogging of 70% can be obtained. .. Here, the clogging determination unit 5 uses the reference threshold value D1 and determines that clogging has not occurred when the maximum discharge pressure is less than the reference threshold value D1 (when it is in the region E0), and determines that clogging has not occurred, and determines that clogging has not occurred for a predetermined period (1 day). ), If the number of times n (in the region E) where the maximum discharge pressure becomes the reference threshold D1 or more is 1 or more, it is determined that there is a sign of clogging, and further, within a predetermined period (1 day). When the number of times n (in the region E) where the maximum discharge pressure becomes the reference threshold value D1 or more is 12 times or more, it is determined that clogging has occurred. The number of times n in this determination is an example.

In FIG. 2, assuming that the outside air temperature is X and the maximum discharge pressure for 1 hour is Y.
The reference threshold D1 is
Y = 0.3214 ・ X + 15.238
The reference threshold D2 is
Y = 0.2406 ・ X + 18.920
The reference threshold D3 is
Y = 0.3877 · X + 20.013
The reference threshold D0 is
Y = 0.3112 · X + 14.795
Is.

<Clogging judgment processing>
FIG. 3 is a flowchart showing a clogging determination processing procedure by the clogging determination unit 5. As shown in FIG. 3, the clogging determination unit 5 first determines whether or not a predetermined period (for example, one day) has elapsed (step S110). If the predetermined period does not elapse (steps S110, No), this determination process is continued. The clogging determination unit 5 samples and acquires the outside air temperature from the temperature sensor Ta, for example, every minute, and also samples and acquires the discharge pressure of the condenser 21 from the pressure sensor P.

On the other hand, when the predetermined period has elapsed (step S110, Yes), the discharge pressure within the predetermined period is collected (step S120), and the outside air temperature within the predetermined period is further collected (step S130). Then, the clogging determination unit 5 acquires the maximum discharge pressure within a unit time (for example, 1 hour) and the outside air temperature at that time (step S140). Then, it is determined whether or not the number of times n at which the maximum discharge pressure becomes the minimum reference threshold D1 or more is 1 or more (step S150). If the number of times n at which the maximum discharge pressure becomes the minimum reference threshold D1 or more is not 1 or more (steps S150 and No), the process proceeds to step S190.

When the number of times n at which the maximum discharge pressure becomes the minimum reference threshold D1 or more is 1 or more (step S150, Yes), it is further determined whether or not the number of times n is 12 or more (step S160). If the number of times n is not 12 or more (step S160, No), a sign alarm output indicating that clogging is suspected is performed (step S170), and the process proceeds to step S190. On the other hand, when the number of times n is 12 or more (step S160, Yes), an alarm output indicating that clogging has occurred (step S180) is performed, and the process proceeds to step S190.

In step S190, it is determined whether or not there is an end instruction of this process (step S190), and if there is no end instruction (step S190, No), the process proceeds to step S110, and the clogging determination process is performed in the next predetermined period. I do. On the other hand, when there is an end instruction (step S190, Yes), this process ends as it is.

As described above, in the present embodiment, the sign or occurrence of clogging is determined based on the number of times that the maximum discharge pressure in a unit time becomes the reference threshold value D1 or more. As described above, since the maximum discharge pressure has an outside air temperature dependence, the maximum discharge pressure is two-dimensional information having a parameter of the outside air temperature. As shown in FIG. 2, the maximum discharge output has a correlation that the maximum discharge pressure increases as the clogging state of the condenser 21 worsens, even if the discharge pressure fluctuates greatly depending on the operating state or the like. Since the reference threshold value D1 is determined based on this maximum discharge pressure and the sign or occurrence of clogging is determined based on the number of times the maximum discharge pressure becomes the reference threshold value D1 or more, a highly accurate sign of clogging is determined. Alternatively, the occurrence can be determined.

<Modification example 1>
In FIG. 2, the region E1 is a region having a reference threshold value D1 or more and less than the reference threshold value D2, and is a region determined to be clogged with 30%. Further, the region E2 is a region having a reference threshold value D2 or more and less than the reference threshold value D3, and is a region determined to be 50% clogged. Further, the region E3 is a region of the reference threshold value D3 or higher, and is a region of 70% clogging. As described above, the region E is a region where clogging is 30% or more.

That is, not only the reference threshold value D1 but also a plurality of stepwise reference threshold values D1 to D3 may be used to further finely and accurately determine the sign or occurrence of clogging.

For example, a predictive alarm output with a higher alarm level may be performed when the maximum discharge pressure is detected in the region E2 than when the maximum discharge pressure is detected in the region E1. Further, the alarm level of the precursor alarm output may be changed depending on the number of times of the maximum discharge pressure generated in each region E1 to E3.

FIG. 4 is a diagram showing an example of the number of times of the maximum discharge pressure generated in the regions E0 to E3. In this case, when the above embodiment is applied, since the maximum discharge pressure is detected once or more in the regions E1 to E3 on May 30, a predictive alarm is output, and after May 31, the region E1 is output. Since the maximum discharge pressure is detected 12 times or more in ~ E3, an alarm output is made. If the clogging exceeds 70%, the cooling capacity is extremely reduced. Therefore, when the maximum discharge pressure is detected once or more in the region E3, an alarm output with a high alarm level may be performed.

Further, FIG. 5 is a diagram showing a display example in which the data shown in FIG. 4 is graphically displayed. The clogging determination unit 5 may display and output the clogging state shown in FIG. 5 graphically in a bar graph or the like in chronological order.

<Modification 2>
FIG. 6 is a block diagram showing a configuration of a cooling system having a function of an abnormality sign detection device, which is a modification 2 of the embodiment of the present invention. In the second modification, the temperature sensor Tb for detecting the discharge temperature of the condenser 21 is provided instead of the pressure sensor P for detecting the discharge pressure of the condenser 21. In the second modification, the maximum discharge temperature is used instead of the maximum discharge pressure to determine the sign or occurrence of clogging of the condenser 21.

That is, the reference threshold value D1 determined by using the maximum discharge temperature instead of the maximum discharge output is stored, and the clogging determination unit 5 determines the number of times that the maximum discharge temperature in a unit time becomes the reference threshold value D1 or more during operation. Based on this, the sign or occurrence of clogging is determined.

Although the embodiments and modifications to which the invention made by the present inventors has been applied have been described above, the present invention is limited by the descriptions and drawings that form a part of the disclosure of the present invention according to the present embodiments and modifications. There is no. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

1 Controller 2 Input / output unit 3 Storage unit 4 Control unit 5 Clog determination unit 10 Prefabricated showcase 11 Inflator 12 Cooler 20 Refrigerator 21 Condenser 100 Store D0 to D3 Reference threshold E, E0 to E3 Area L Piping N network n times P pressure sensor Ta, Tb temperature sensor

Claims (5)

An abnormality sign detection device that detects an abnormality in the condenser in a cooling system in which the cooler exchanges heat with the cooling space by a refrigerant circulating through a refrigerator including a condenser.
The clogging state of the condenser is set in advance, the maximum discharge pressure of the condenser corresponding to the set clogging state in a unit time is obtained, and the clogging state occurs based on the maximum discharge pressure. A storage unit that obtains a reference threshold value for the maximum discharge pressure of the vessel and stores the reference threshold value,
A pressure sensor that detects the discharge pressure of the condenser and
A clogging determination unit that determines a sign or occurrence of clogging of the condenser based on the number of times that the maximum discharge pressure in a unit time detected by the pressure sensor becomes equal to or higher than the reference threshold value within a predetermined period.
An abnormality sign detection device characterized by being equipped with. Equipped with an outside air temperature sensor that detects the outside air temperature
The maximum discharge pressure in a unit time of the condenser is two-dimensional information with the outside air temperature detected by the outside air temperature sensor as a parameter.
The abnormality sign detection device according to claim 1, wherein the reference threshold value is a characteristic curve that approximates the relationship between the maximum discharge pressure and the outside air temperature. The clogging state is a plurality of stepwise clogging states.
The reference threshold is determined for each of the plurality of stepwise clogging states.
The clogging determination unit is characterized in that, based on the plurality of reference threshold values, a plurality of corresponding stepwise clogging states are detected to determine a sign or occurrence of clogging of the condenser. The abnormality sign detection device according to claim 1 or 2. The abnormality sign detecting device according to any one of claims 1 to 3, wherein the clogging determining unit outputs a sign or occurrence of clogging of the condenser to an output unit. A temperature sensor for detecting the discharge temperature of the condenser is provided.
The abnormality according to any one of claims 1 to 4, wherein a sign of clogging of the condenser is determined by using the maximum discharge temperature of the condenser instead of the maximum discharge pressure of the condenser. Sign detector.

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