JP6813786B2 - Refrigerant leak detection method and refrigerant leak detection means - Google Patents

Description

The present invention is a circulation path applied to a refrigerating and air-conditioning device, for example, a liquid phase and a gas phase inside a refrigerant circulation pipe including a heat exchanger, a compressor, an evaporator, and an extension pipe connecting them. The present invention relates to a refrigerant leak detecting method and a refrigerant leak detecting means for detecting the leakage of the refrigerant circulating while changing the state.

Conventionally, as a method of detecting refrigerant leakage, in a refrigerant circulation pipe in an operating state, the amount of liquid refrigerant in the refrigerant pipe in which the inside of the pipe is recognized as a liquid phase state and the amount of liquid refrigerant in the refrigerant pipe in which the inside of the pipe is recognized as a gas (gas phase) state are used. By calculating the amount of gas refrigerant based on the pressure and temperature of the refrigerant detected by various sensors provided in the pipeline, the current total amount of refrigerant existing in the refrigerant circulation pipe is derived, and the current total amount is further derived. And, there is a device that detects the leakage amount of the refrigerant in the refrigerant circulation pipe by deriving the difference from the initial total amount of the refrigerant stored as a known amount (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-89717 (Page 9, FIG. 1)

However, in Patent Document 1, among the devices constituting the refrigerant circulation pipe, the liquid phase refrigerant and the gas state refrigerant such as a receiver and a cooler having a certain amount of internal capacity pass through the liquid surface. In either case, the amount of refrigerant in the existing equipment cannot be calculated accurately, and as a result, an error occurs in the total amount of refrigerant in the refrigerant circulation pipe, and there is a risk that the desired refrigerant leakage cannot be detected. There is.

The present invention has been made by paying attention to such a problem, and by accurately deriving the total amount of the refrigerant existing in the liquid phase state and the gas state in various devices constituting the refrigerant circulation pipe. It is an object of the present invention to provide a refrigerant leak detecting method and a refrigerant leak detecting means capable of detecting a refrigerant leak in the period.

In order to solve the above problems, the refrigerant leakage detection method of the present invention is used.
Refrigerant circulation that is applied to refrigeration and air conditioners This is a refrigerant leakage detection method that detects the leakage of refrigerant that circulates in the piping.
The level sensor detects the liquid level of the liquid refrigerant in the refrigerant storage device having a certain internal capacity among the piping devices constituting the refrigerant circulation pipe.
Based on the liquid level, the amount of liquid refrigerant below the liquid level in the refrigerant storage device is calculated, and the amount of gas refrigerant above the liquid level in the refrigerant storage device is calculated.
At least based on the amount of the liquid refrigerant and the amount of the gas refrigerant, the current amount of the refrigerant to be detected for leakage is derived.
It is characterized in that leakage of the refrigerant in the refrigerant circulation pipe is detected based on the difference between the current amount of the refrigerant and the reference reference refrigerant amount in the refrigerant circulation pipe.
According to this feature, the amount of refrigerant existing in the liquid phase and the gas phase in the refrigerant storage device is calculated by detecting the liquid level in the refrigerant storage device that changes according to the operating condition of the refrigerating and air-conditioning device with a level sensor. Since the current amount of refrigerant to be detected for leakage in the refrigerant circulation pipe can be accurately derived, the presence or absence of refrigerant leakage and the amount of leakage can be accurately determined based on the difference between the current amount of refrigerant and the reference amount of refrigerant. It can be detected.

The reference refrigerant amount is characterized in that it is an initial refrigerant amount derived from the amount of the refrigerant initially introduced into the refrigerant circulation pipe based on the detection by the level sensor.
According to this feature, the reference refrigerant amount is derived based on the same level sensor as the current refrigerant amount. Therefore, by calculating the difference between the reference refrigerant amount and the current refrigerant amount, it depends on the individual difference and tolerance of the level sensor. The detection error is offset and the detection accuracy is improved.

The refrigerant leak detecting means used in the refrigerant leak detecting method of the present invention is
The refrigerant storage device is characterized by having a wider plane cross section than the liquid refrigerant pipe connected to the refrigerant storage device.
According to this feature, the fluctuation of the liquid level in the refrigerant storage device is lessened than the fluctuation in the liquid refrigerant pipe, so that the risk of detection error due to the fluctuation of the liquid level can be avoided.

The level sensor is characterized in that it is provided via a communication pipe that communicates with the refrigerant storage device.
According to this feature, by extending the communication pipe from the refrigerant storage device to the desired position, not only the liquid level level can be easily detected, but also the liquid level fluctuation in the refrigerant storage device is directly affected. The liquid level is stable.

The refrigerant storage device includes at least a first refrigerant storage device that stores a refrigerant that changes state from a gas phase to a liquid phase and a second refrigerant storage device that stores a refrigerant that changes state from a liquid phase to a gas phase. It is a feature.
According to this feature, in the refrigerant circulation pipe in which the refrigerant circulates while changing the state between the liquid phase and the gas phase, the first refrigerant storage device that changes the state from the gas phase to the liquid phase and the liquid phase to the gas phase By detecting the liquid level with the second refrigerant storage device that stores the state-changing refrigerant, the boundary between the liquid-phase part and the gas-phase part of the refrigerant in the entire refrigerant circulation pipe becomes clear, and by extension, the refrigerant. The total amount of can be accurately derived.

It is a piping diagram which shows the refrigerant circulation piping in Example 1, and is a control block diagram thereof. (A) is a partial cross-sectional view showing a liquid level gauge, and (b) is a cross-sectional view taken along the line AA of (a). It is a piping diagram which shows the refrigerant circulation piping in Example 2. FIG.

A mode for implementing the refrigerant leakage detection method and the refrigerant leakage detection means according to the present invention will be described below based on examples.

The refrigerant leakage detection method according to the first embodiment will be described with reference to FIGS. 1 and 2. First, reference numeral 1 in FIG. 1 is a refrigerant circulation pipe applied to the low source side refrigeration cycle of the refrigeration and air conditioner of the dual refrigeration cycle.

The refrigerant circulation pipe 1 is composed of a pipe member that communicates and connects in a sealed state as a circulation path whose inside is closed. When each component device of the refrigerant circulation pipe 1 is classified according to the phase state of the refrigerant existing inside the refrigerant circulation pipe 1, it stores the gas refrigerant pipe 2 in which the internal refrigerant is in the gas phase state and the refrigerant whose state changes from the gas phase to the liquid phase. A receiver 10 as a first refrigerant storage device, a liquid refrigerant pipe 3 in which the internal refrigerant is in a liquid phase state, and a cooler 20 as a second refrigerant storage device for storing a refrigerant whose state changes from the liquid phase to the gas phase. Consists of. Further, the gas refrigerant pipe 2 is mainly composed of a low pressure gas pipe 2a and a high pressure gas pipe 2b, and the liquid refrigerant pipe 3 is mainly composed of a low pressure liquid pipe 3a and a high pressure liquid pipe 3b.

The refrigerant circulation pipe 1 of this embodiment is configured as a low-source refrigeration cycle in a dual refrigeration cycle, and R23 having a relatively low boiling point is applied as a refrigerant, and another closed system is used via a cascade capacitor 9. It exchanges heat with the high-source side refrigeration cycle 50 to which a refrigerant (R404A or the like) having a relatively high boiling point is applied in the circulation path. As is well known, R23 is applied as an alternative CFC that does not deplete the ozone layer, but on the other hand, it is known as a refrigerant having a high global warming potential (GWP), and its leakage needs to be strictly detected.

Although R23 is applied as the refrigerant in this embodiment, it can also be applied to other refrigerants such as CFC substitutes, ammonia and carbon dioxide. Further, in this embodiment, the application is applied to the low source side refrigeration cycle of the dual refrigeration cycle, but the present invention is not limited to this, and can be applied to various refrigeration and air conditioners as long as it constitutes a closed circulation path.

The circulation path of the refrigerant circulation pipe 1 will be described in order with reference to FIG. In FIG. 1, the white arrow indicates the refrigerant in the low pressure state, and the black arrow indicates the refrigerant in the high pressure state.

First, when the low-pressure gas-state refrigerant whose state has changed from the liquid phase to the gas phase in the cooler 20 is sent out from the cooler 20, the liquid portion contained in the refrigerant is separated by the liquid separator 4, and the gas refrigerant pipe 2 It is introduced into the low-source compressor unit 5 via the low-pressure gas pipe 2a.

The low source compressor unit 5 is mainly composed of a compressor 6 that boosts low pressure gas to a high pressure state and an oil separator 7 as an auxiliary machine. The compressor 6 compresses the low-pressure gas by a driving force generated by a rotating mechanism or a reciprocating mechanism (not shown) and boosts the pressure to a high-pressure state, and the oil separator 7 separates the lubricating oil mixed in the refrigerant. It is returned to the compressor 6.

The refrigerant introduced into the low-source compressor unit 5 is boosted by the compressor 6 and sent out as high-pressure gas to the high-pressure gas pipe 2b of the gas refrigerant pipe 2, and is introduced into the cascade condenser 9. The cascade condenser 9 is a heat exchanger in which the condenser 2c of the low-source side refrigeration cycle, which is the refrigerant circulation pipe 1 of the present embodiment, and the evaporator 50a of the high-source side refrigeration cycle 50 are integrally formed.

That is, the high-pressure gas-state refrigerant introduced into the cascade condenser 9 is cooled by heat exchange with the evaporator 50a of the high-source side refrigeration cycle 50 in the condenser 2c, and the state changes from the gas phase to the liquid phase. It is introduced in the receiver 10.

The receiver 10 is composed of a high-pressure resistant sealed container having a relatively large diameter and a substantially cylindrical shape that is horizontally placed and has a constant internal capacity, and is connected to a high-pressure gas pipe 2b that serves as an inlet for a refrigerant at the upper end of the sealed container. The 10a and the lower end of the sealed container are provided with a connection portion 10b with a high-pressure liquid pipe 3b serving as an outlet portion of the refrigerant. Further, in the receiver 10, inside the sealed container, the gas (gas phase) state refrigerant stored in the upper layer portion and the liquid phase state refrigerant stored in the lower layer portion are liquids of the liquid phase state refrigerant. Both exist with the surface as the boundary surface.

The plane cross section forming the liquid level inside the receiver 10 is formed in an area larger than the plane cross section of the high-pressure liquid pipe 3b extending in the vertical direction. Further, the receiver 10 is provided with a liquid level gauge 13 for measuring the liquid level of the liquid refrigerant in a communicating state via communication pipes 11 and 12 connected to the upper and lower portions thereof. Here, the plane cross section means a cross section parallel to the horizontal plane.

As shown in FIGS. 2 (a) and 2 (b), the liquid level gauge 13 is composed of a high-pressure resistant sealed container having a relatively small diameter, a vertically placed cylindrical shape, and a constant plane cross section, and gas is placed on the upper part of the sealed container. A connection portion 13a with a communication pipe 11 through which the (gas phase) refrigerant flows, and a connection portion 13b with the communication pipe 12 through which the liquid phase refrigerant flows are provided below the sealed container. That is, since the inside of the liquid level gauge 13 communicates with the inside of the receiver 10 and has the same pressure, the liquid level of the liquid refrigerant in the liquid level gauge 13 is the liquid of the liquid refrigerant in the receiver 10 communicating with the liquid level gauge 13. It follows the surface level and is always formed at the same height.

Further explaining the liquid level gauge 13 in detail, the liquid level gauge 13 of this embodiment is a so-called magnetic liquid level gauge, and the specific gravity inside the sealed container constituting the liquid level gauge 13 is higher than that of the refrigerant in the liquid phase state. A small-diameter columnar magnet float 14 having a light weight is arranged so as to be movable in the vertical direction according to the liquid level of the liquid refrigerant in the sealed container.

Further, a visual window 16 made of a transparent acrylic plate or the like is provided on the side of the sealed container constituting the liquid level gauge 13 in the vertical direction, and a rotor made of a magnetic material is vertically provided on the visual window 16 as a scale. Multiple windows are installed side by side (not shown). The individual rotors are provided so as to be reversible by magnetic force according to the height position of the magnet float 14 in the sealed container. For example, the rotor below the liquid level where the magnet float 14 is located is given a predetermined color. Rotors above the liquid level are configured to face the back side with a different color.
Further, on the side portion of the sealed container constituting the liquid level gauge 13 opposite to the visual window 16, the liquid level level numerical data detected by the inverted rotor is converted into an electric signal and transmitted at a level that can be transmitted. A vessel 15 is provided. The level transmitter 15 can transmit, for example, to the input unit 32 of the control means 30 described later by a signal cable or the like (not shown), and transmits with an analog current or shortens the time interval of the digital signal to several seconds or minutes. By setting and transmitting, it is possible to constantly monitor the liquid level in the receiver 10.
The administrator can also visually check the height of the magnet float 14 in the liquid level gauge 13 through the visual window 16, that is, the liquid level by the difference in the color of the rotor inverted on the front side and the back side.

That is, the receiver 10 is a refrigerant leakage detecting means used in the refrigerant leakage detecting method of the present invention, and constitutes a first refrigerant storage device that stores a refrigerant whose state changes from a gas phase to a liquid phase.

The liquid level level detecting means of the liquid refrigerant in the receiver 10 is not necessarily limited to the magnet type liquid level gauge 13 of the present embodiment, and may be, for example, a differential pressure type or a capacitance type liquid level gauge.

The high-pressure liquid refrigerant sent from the lower end of the receiver 10 to the high-pressure liquid pipe 3b enters the low-pressure liquid state by passing through the expansion valve 8, is introduced into the cooler 20 via the low-pressure liquid pipe 3a, and is introduced into the cooler 20. The state changes from the liquid phase to the gas phase within 20.

The cooler 20 is composed of a high-pressure resistant sealed container having a relatively large diameter and a substantially cylindrical shape that is horizontally placed and has a constant internal capacity, and is connected to a low-pressure liquid pipe 3a that serves as an inlet for a refrigerant at the lower end of the sealed container. 20b and a connection portion 20a with a low-pressure gas pipe 2a serving as an outlet portion of the refrigerant are provided at the upper end portion of the sealed container. Further, in the cooler 20, the refrigerant in the gas (gas phase) state stored in the upper layer portion and the refrigerant in the liquid phase state stored in the lower layer portion are liquids of the refrigerant in the liquid phase state inside the sealed container. Both exist with the surface as the boundary surface.

The plane cross section forming the liquid level inside the cooler 20 is formed in an area larger than the plane cross section of the low pressure liquid pipe 3a extending in the vertical direction. Further, the cooler 20 is provided with a liquid level gauge 23 for measuring the liquid level of the liquid refrigerant in a communicating state via communication pipes 21 and 22 connected to the upper and lower portions thereof.

The liquid level gauge 23 is composed of a high-pressure resistant sealed container having a relatively small diameter, a vertically placed cylindrical shape, and a constant plane cross section, and communicates with a communication pipe 21 in which a gas (gas phase) refrigerant flows in the upper part of the sealed container. A connection portion and a connection portion with a communication pipe 22 through which a liquid-phase gas flows are provided below the sealed container. That is, since the inside of the liquid level gauge 23 communicates with the inside of the cooler 20 and has the same pressure, the liquid level of the liquid refrigerant in the liquid level gauge 23 is the liquid of the liquid refrigerant in the cooler 20 communicating with the liquid level gauge 23. It follows the surface level and is always formed at the same height.

Since the liquid level gauge 23 provided in the cooler 20 has the same configuration as the liquid level gauge 13 provided in the receiver 10 described above, detailed description thereof will be omitted.

That is, the cooler 20 is a refrigerant leakage detecting means used in the refrigerant leakage detecting method of the present invention, and constitutes a second refrigerant storage device that stores a refrigerant whose state changes from a liquid phase to a gas phase.

Next, a method of detecting the amount of refrigerant existing in the refrigerant circulation pipe 1 will be described.

The total amount of refrigerant (weight) existing in the refrigerant circulation pipe 1 is derived by adding up the amount of refrigerant (weight) existing in the gas phase state and the amount of refrigerant (weight) existing in the liquid phase state. .. The total amount (weight) of the refrigerant is calculated by a control means described later, and the pressure gauges PG1 to PG3 arranged in the refrigerant circulation pipe 1, the liquid level gauges 13, 14, etc., the volume in the piping equipment, etc. It is calculated by the control means 30 including the storage unit 31 that stores the known amount of the above, and the control unit 33 that calculates based on the data measured by these measuring instruments.

It is assumed that the low-pressure gas pipe 2a of the refrigerant circulation pipe 1 is filled only with the gas refrigerant in the low-pressure state. Since the internal volume (V1) of the low-pressure gas pipe 2a is a constant amount and is a known amount, the internal pressure (P1) of the low-pressure gas pipe 2a is measured as a variable based on the pressure gauges PG2 and PG3, and the gas density is calculated. Therefore, the amount of refrigerant (W1), which is the weight of the refrigerant in the low-pressure gas pipe 2a, can be calculated.

Strictly speaking, a small amount of liquid refrigerant is present in the liquid separator 4 constituting the low-pressure gas pipe 2a, but the amount thereof is extremely small compared to the internal volume (V1) of the low-pressure gas pipe 2a. Therefore, the measurement accuracy can be ensured without including it in the calculation.

The amount of refrigerant (weight) can be calculated more accurately by actually measuring the internal temperature of the piping equipment as another variable, but by setting a predetermined value that is assumed as the temperature during operation or non-operation in advance. , The measurement accuracy can be ensured without actually measuring the temperature.

Similarly, it is assumed that the high-pressure gas pipe 2b of the refrigerant circulation pipe 1 is filled with only the high-pressure gas refrigerant. Since the internal volume (V2) of the high-pressure gas pipe 2b is a constant amount and is a known amount, the internal pressure (P2) of the high-pressure gas pipe 2b is measured as a variable based on the pressure gauge PG1 and the gas density is calculated. The amount of refrigerant (W2) in the high-pressure gas pipe 2b can be calculated.

Further, among the refrigerant circulation pipes 1, it is assumed that the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a constituting the liquid refrigerant pipe 3 are filled only with the refrigerant in the liquid phase state. Since the internal volume (V3) of the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a is a constant amount and is a known amount, the internal pressure (P2) of the high-pressure liquid pipe 3b is measured based on the pressure gauge PG1 as a variable to measure the high-pressure liquid density. In addition to the calculation, the internal pressure (P1) of the low-pressure liquid pipe 3a is measured as a variable based on the pressure gauge PG2, and the low-pressure liquid density is calculated to obtain the amount of refrigerant (W3) in the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a. Can be calculated.

Since the refrigerant applied in the present invention can be treated as an incompressible fluid in its liquid state, the measurement accuracy should be ensured without actually measuring the internal pressures of the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a. Can be done. That is, the amount of refrigerant (W3) in the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a can be treated as a constant known amount that does not fluctuate regardless of whether the refrigerating air conditioner is operating, not operating, or in an operating state. it can.

Next, detection of the amount of refrigerant in the receiver 10 in the refrigerant circulation pipe 1 will be described.

First, the liquid level of the liquid refrigerant in the receiver 10 is detected based on the liquid level meter 13 described above. In the case of this embodiment, as described above, the liquid level of the liquid refrigerant in the receiver 10 can be detected by the rotor that flips over according to the height position of the magnet float 14 in the liquid level meter 13. The numerical data of the liquid level detected by the inverted rotor is converted into an electric signal by the level transmitter 15 and transmitted to the input unit 32 of the control means 30 described later, so that the data is always detected. With the liquid level of the liquid refrigerant in the receiver 10 as the boundary, the liquid-phase refrigerant is stored below the liquid level in the receiver 10, and the gas-phase state is above the liquid level. It can be certified that the refrigerant is stored. The liquid level in the receiver 10 can also be detected by the administrator reading the color scheme applied to the front and back of the magnet float 14 through the visual window 16 of the liquid level meter 13.

The control unit 33 of the control means 30 can calculate the internal volume of the receiver 10 at an arbitrary liquid level, that is, the internal volume from the lower end inside the receiver 10 to the liquid level. Therefore, by detecting the liquid level in the receiver 10, the internal volume (V4) of the liquid refrigerant existing below the liquid level is calculated, and the pressure gauge PG1 for the gas refrigerant provided above the receiver 10 is calculated. By calculating the liquid density based on the internal pressure (P5) of the upper part of the receiver 10 measured in the above, the amount of refrigerant (W4) of the liquid refrigerant inside the receiver 10 can be calculated.

Further, the control unit 33 of the control means 30 can calculate the amount of gas refrigerant at an arbitrary liquid level of the receiver 10, that is, the internal volume inside the receiver 10 from the liquid level to the upper end. Therefore, by detecting the liquid level in the receiver 10, the internal volume (V5) of the gas refrigerant existing above the liquid level is calculated, and the pressure gauge PG1 for the gas refrigerant provided above the receiver 10 is calculated. By calculating the gas density based on the internal pressure (P5) of the upper part of the receiver 10 measured in the above, the amount of refrigerant (W5) of the gas refrigerant inside the receiver 10 can be calculated.

Next, the detection of the amount of refrigerant in the cooler 20 in the refrigerant circulation pipe 1 will be described.

First, the liquid level of the liquid refrigerant in the cooler 20 is detected based on the liquid level meter 23 described above. In the case of this embodiment, the liquid level of the liquid refrigerant in the cooler 20 can be detected by a rotor that flips over according to the height position of the magnet float in the liquid level meter 23, similarly to the liquid level meter 13 described above. The numerical data of the liquid level detected by the inverted rotor is converted into an electric signal by the level transmitter and transmitted to the input unit 32 of the control means 30 described later, so that the data is always detected. With the detected liquid level of the liquid refrigerant in the cooler 20 as a boundary, the liquid-phase refrigerant is stored below the liquid level in the cooler 20, and the gas-phase state is above the liquid level. It can be certified that the refrigerant is stored. The liquid level in the cooler 20 can also be detected by the administrator reading the color scheme applied to the front and back of the magnet float through the visual window of the liquid level meter 23.

The control unit 33 of the control means 30 can calculate the internal volume of the cooler 20 at an arbitrary liquid level, that is, the internal volume from the lower end inside the cooler 20 to the liquid level. Therefore, by detecting the liquid level in the cooler 20, the internal volume (V6) of the liquid refrigerant existing below the liquid level is calculated, and the pressure gauge PG2 for the gas refrigerant provided above the cooler 20 is calculated. The liquid density can be calculated based on the internal pressure (P7) of the upper part of the cooler 20 measured in the above, and the amount of refrigerant (W6) of the liquid refrigerant inside the cooler 20 can be calculated.

Further, the control unit 33 of the control means 30 can calculate the amount of gas refrigerant at an arbitrary liquid level of the cooler 20, that is, the internal volume of the inside of the cooler 20 from the liquid level to the upper end. Therefore, by detecting the liquid level in the cooler 20, the internal volume (V7) of the gas refrigerant existing above the liquid level is calculated, and the pressure gauge PG2 for the gas refrigerant provided above the cooler 20 is calculated. The gas density can be calculated based on the internal pressure (P7) of the upper part of the cooler 20 measured in the above, and the amount of refrigerant (W7) of the gas refrigerant inside the receiver 10 can be calculated.

As described above, in the first embodiment, the amount of refrigerant (W1) to (W7) inside the low-pressure gas pipe 2a, the high-pressure gas pipe 2b, the high-pressure liquid pipe 3b and the low-pressure liquid pipe 3a, the receiver 10, and the cooler 20. ) Are calculated and all of them are added up to derive the total amount of refrigerant (WT) contained in the refrigerant circulation pipe 1 which is a closed circulation path, and the total amount of refrigerant (WT) is used as the basis for the amount of refrigerant. Leakage can be detected.

Next, the control means for controlling the refrigerant leakage detection will be described.

As shown in FIG. 1, the control means 30 constitutes a refrigerant leakage detecting means, and is mainly composed of a storage unit 31, an input unit 32, a control unit 33, a display unit 34, and an output unit 35, which will be described later. , Preferably, it is arranged in a monitoring room or the like (not shown) near the above-mentioned refrigerant circulation pipe 1.

The storage unit 31 stores fixed values such as the pipe diameter, extension, and internal volume of each pipe member that do not fluctuate, and is input to each refrigerant circulation pipe 1 applied to each refrigerating and air-conditioning device at the initial stage of installation. It is a thing. Strictly speaking, values such as liquid density and gas density that change based on temperature may be stored in place of the values at the representative temperature.

The input unit 32 is for inputting various measured values such as the liquid level and the pressure value in the refrigerant circulation pipe 1, and these measured values may be input as an electric signal or read by the administrator. The value may be input using a keyboard, touch panel, or the like. Further, the input unit 32 can input a leak alarm installation value (WS), which is a reference refrigerant weight for determining that a leak has occurred in the refrigerant circulation pipe 1.

The control unit 33 is based on the measured value input to the input unit 32 and the fixed value stored in the storage unit 31, the gas refrigerant pipe 2, the liquid refrigerant pipe 3, the receiver 10, and the liquid refrigerant and the gas refrigerant in the cooler 20. By calculating the calculated values such as the amount of the refrigerant in the above and totaling them, the current total amount of the refrigerant (WT) to be detected for leakage in the refrigerant circulation pipe 1 is calculated.

The leakage alarm installation value (WS) can be set and input as an appropriate value, but in this embodiment, the initial total refrigerant amount (WA), which is the weight of the refrigerant initially charged into the refrigerant circulation pipe 1, is used. , The measured value input to the input unit 32 based on the receiver 10 detected by the liquid level gauges 13 and 23, the liquid level in the cooler 20, and the storage, as in the case of the current total refrigerant amount (WT) described above. By calculating based on the fixed value stored in the unit 31, it is acquired as the initial total refrigerant amount (WA), and the predetermined allowable error and the allowable leakage amount (Wa) are subtracted from the initial total refrigerant amount (WA). Is set and input as the leakage alarm installation value (WS).

Further, the control unit 33 calculates the difference between the calculated current total refrigerant amount (WT) and the leak alarm installation value (WS), and when the total refrigerant amount (WT) exceeds the leak alarm installation value (WS). Is determined to be a normal state without leakage, and when the total amount of refrigerant (WT) is equal to or less than the leakage alarm installation value (WS), it is determined to be an abnormal state in which leakage has occurred. That is, the control unit 33 detects the leakage of the refrigerant in the refrigerant circulation pipe 1 based on the difference between the current amount of refrigerant and the reference reference refrigerant amount in the refrigerant circulation pipe 1.

The display unit 34 is for displaying the fixed value stored in the storage unit 31, the measured value input to the input unit 32, and the calculated value calculated by the control unit 33. Although not particularly shown, the display unit 34 displays, for example, a list display screen that displays the above-mentioned fixed value, measured value, calculated value, and total refrigerant amount (WT) in a list, or the display unit 34 displays the calculated value over time. Display a graph display screen that is displayed as a line graph or the like.

Although not particularly shown, the display unit 34 displays a normal screen with, for example, a blue background color when the control unit 33 determines that it is in a normal state, while the display unit 34 displays when it determines that the control unit 33 is in an abnormal state. 34 displays, for example, a red background color and blinking of the screen as an abnormal screen, or the output unit 35 emits an alarm sound to notify the abnormal state.

Further, the output unit 35 externally displays the fixed value stored in the storage unit 31, the measured value input to the input unit 32, the calculated value calculated by the control unit 33, and the normal state or abnormal state of the refrigerant circulation pipe 1. It may be output, and may be transmitted externally via various lines, or may be recorded on a storage medium.

The above-mentioned refrigerant leakage detection may be performed continuously at all times, intermittently at predetermined time intervals set arbitrarily, or at a predetermined event such as when the refrigerating and air-conditioning equipment is started or temporarily stopped. This may be performed when the above occurs, or a combination of these may be performed.

Preferably, the refrigerant leak detection is performed continuously or every few minutes when the refrigerating and air-conditioning equipment is in operation, and every few hours when the refrigerating and air-conditioning equipment is not in operation, so that early emergency measures can be taken in case of leakage during operation. If the refrigerant leaks due to pressure fluctuations in the piping caused by the phase change during non-operation of the refrigeration air conditioner, which can be taken and is easily affected by the outside temperature and the refrigerant changes phase, the leaked state Restoration measures can be taken to avoid the risk of starting operation.

Next, the refrigerant leakage detection method according to the second embodiment will be described with reference to FIG. It should be noted that the same configuration as in the above embodiment and overlapping description will be omitted.

The refrigerant circulation pipe 40 is composed of a piping member that is communicated and connected as a closed circulation path in a sealed state, and has the same configuration as the refrigerant circulation pipe 1 of the first embodiment except for the protection pipe 41 described later. ..

As shown in FIG. 3, the protection pipe 41 is a branch gas pipe 42a branched from the low pressure gas pipe 2a arranged between the liquid separator 4 and the low source compressor unit 5 via the pressure regulating valve 43. Between the low source compressor unit 5 and the cascade condenser 9 via a protective container 45 formed of a sealed housing having a constant capacity to which the branch gas pipe 42a is connected and a pressure regulating valve 44 connected to the protective container 45. It is composed of a branch gas pipe 42b connected to the arranged high pressure gas pipe 2b.

That is, the refrigerant circulation pipe 40 has substantially the same internal volume as the refrigerant circulation pipe 1 of the first embodiment when the pressure adjusting valves 43 and 44 of the protection pipe 41 are closed, and the pressure of the protection pipe 41 When the adjusting valves 43 and 44 are open, the refrigerant circulation pipe 1 has an internal volume in which the protective pipe 41 is added.

The pressure regulating valves 43 and 44 are in a closed state when, for example, the low-pressure gas pipe 2a and the high-pressure gas pipe 2b have an appropriate gas pressure within a predetermined range during operation, and on the other hand, for example, when the operation is stopped for a certain period of time. When the temperature of the refrigerant inside the pipe rises to near room temperature and a part of the refrigerant evaporates and the gas pressure rises beyond the above-mentioned predetermined range, the gas pressure becomes an open state. It is possible to prevent an excessive rise in the internal gas pressure by allowing a part of the refrigerant in a gaseous state to flow in.

Therefore, the refrigerant circulation pipe 40 of the present embodiment detects leakage by the same measurement as that of the first embodiment, assuming that the pressure regulating valves 43 and 44 are in a closed state during operation, for example. On the other hand, in a specific case such as when the operation is stopped for a certain period of time, as the temperature of the refrigerant inside the pipe rises to near room temperature, a part of the refrigerant evaporates and the internal gas pressure rises, and the pressure regulating valves 43 and 44 are temporarily closed. It is considered that the protective pipe 41 mainly composed of the protective container 45 is considered to be open, and it is assumed that the inside of the protective pipe 41 mainly composed of the protective container 45 is filled with only a certain amount of gas refrigerant. Since the internal volume (V8) of the protective pipe 41 is a constant amount and is a known amount, the internal pressure (P8) of the protective container 45 is measured as a variable based on the pressure gauge PG4, and the gas density is calculated to calculate the protective pipe. The amount of refrigerant (W8) in 41 can be calculated.

In the first embodiment, the amounts of refrigerants (W1) to (W7) inside the low-pressure gas pipe 2a, the high-pressure gas pipe 2b, the high-pressure liquid pipe 3b, the low-pressure liquid pipe 3a, the receiver 10, and the cooler 20 are calculated, respectively. Further, by calculating the amount of refrigerant (W8) in the protective pipe 41 and adding up all of them, the total amount of refrigerant (WT) contained in the refrigerant circulation pipe 40, which is a closed circulation path, can be derived. Refrigerant leakage can be detected based on the total amount of refrigerant (WT).

According to the refrigerant leakage detection method of the present invention described above, the liquid level gauges 13 and 23 in the receiver 10 as the refrigerant storage device and the liquid level in the cooler 20 as the level sensor change according to the operating condition of the refrigerating air conditioner. The total amount of refrigerant (WT), which is the current amount of refrigerant to be detected for leakage in the refrigerant circulation pipe 1, can be calculated by detecting the amount of refrigerant existing in the liquid phase and the gas phase in the receiver 10 and the cooler 20. ) Can be accurately derived, so the presence or absence of refrigerant leakage and the amount of leakage should be detected with high accuracy based on the difference between the total amount of refrigerant (WT) and the reference refrigerant amount, the leakage alarm installation value (WS). Can be done.

Further, since the reference refrigerant amount is derived based on the liquid level gauges 13 and 23 as the same level sensor as the current refrigerant amount, the difference between the reference refrigerant amount and the current refrigerant amount is calculated to obtain the liquid level gauge 13, The detection error due to individual differences and tolerances of 23 is offset, and the detection accuracy is improved.

Further, since the receiver 10 has a plane cross section wider than that of the liquid refrigerant pipe 3 connected to the receiver 10, fluctuations in the liquid level in the receiver 10 are mitigated more than fluctuations in the liquid refrigerant pipe 3. It is possible to avoid the risk of detection error due to fluctuations in the liquid level.

Similarly, since the cooler 20 has a wider plane cross section than the liquid refrigerant pipe 3 connected to the cooler 20, fluctuations in the liquid level in the cooler 20 are alleviated more than fluctuations in the liquid refrigerant pipe 3. , The risk of detection error due to fluctuation of the liquid level can be avoided.

Further, since the float 14 as a liquid level sensor is provided in the inner cylinder that communicates with the receiver 10 and the cooler 20 via the communication pipes 11, 12, 21 and 22, from the receiver 10 and the cooler 20 to the desired position. By extending the communication pipes 11, 12, 21 and 22, not only the liquid level can be easily detected, but also the liquid level is not directly affected by the fluctuation of the liquid level in the receiver 10 and the cooler 20. Stabilize.

The receiver 10 as a first refrigerant storage device for storing the refrigerant whose state changes from the gas phase to the liquid phase, and the cooler 20 as the second refrigerant storage device for storing the refrigerant whose state changes from the liquid phase to the gas phase. By detecting the liquid level, the boundary between the liquid phase portion and the gas phase portion of the refrigerant in the entire refrigerant circulation pipe 1 becomes clear, and the total amount of the refrigerant can be accurately derived.

Although examples of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these examples, and any changes or additions within the scope of the gist of the present invention are included in the present invention. Is done.

For example, in the above embodiment, the receiver 10 and the cooler 20 are applied as the refrigerant storage device for detecting the liquid level, but the present invention is not limited to this, and for example, a refrigerant whose state changes from the gas phase to the liquid phase of the receiver or the like is stored. It may be applied only to the refrigerant storage device, or may be applied only to the refrigerant storage device that stores the refrigerant whose state changes from the liquid phase to the gas phase such as a cooler.

1 Refrigerant circulation piping 2 Gas refrigerant piping 2a Low pressure gas piping 2b High pressure gas piping 3 Liquid refrigerant piping 3a Low pressure liquid piping 3b High pressure liquid piping 5 Low source compressor unit 6 Compressor 8 Expansion valve 9 Cascade condenser 10 Receiver (1st refrigerant storage device) )
11, 12 Communication pipes 13, 23 Liquid level gauge (level sensor)
14 Magnet float 15 Level transmitter 16 Visual window 20 Cooler (second refrigerant storage device)
21, 22 Communication pipe 30 Control means 40 Refrigerant circulation pipe 41 Protective pipe 45 Protective container 50 High source side refrigeration cycle

Claims (4)

A refrigerant that is applied to a refrigeration and air conditioner and is configured as a low-source refrigeration cycle in a dual refrigeration cycle, and circulates in a refrigerant circulation pipe that is connected in the order of a cascade condenser, a receiver, an expansion valve, a cooler, a liquid separator, and a compressor unit. It is a refrigerant leakage detection method that detects the leakage of
Of the piping equipment that constitutes the refrigerant circulation pipe, a refrigerant that is connected above the liquid refrigerant pipe, has a constant internal capacity, has a wider plane cross section than the liquid refrigerant pipe, and changes its state from the liquid phase to the gas phase. The level sensor detects the liquid level of the liquid refrigerant in the cooler consisting of a sealed container for storage, and then
Based on the liquid level, the amount of liquid refrigerant below the liquid level in the cooler is calculated, and the amount of gas refrigerant above the liquid level in the cooler is calculated.
Assuming that the refrigerant in the gas pipe and the liquid separator connected above the cooler is the gas refrigerant, the amount of the gas refrigerant in the gas pipe and the liquid separator is calculated.
The liquid refrigerant in the receiver, which is connected below the gas pipe, has a constant internal capacity, has a wider plane cross section than the liquid refrigerant pipe, and is a sealed container for storing a refrigerant whose state changes from a gas phase to a liquid phase. The level of the liquid level is detected by the level sensor,
Based on the liquid level, the amount of liquid refrigerant below the liquid level in the receiver is calculated, and the amount of gas refrigerant above the liquid level in the receiver is calculated.
The refrigerant in the liquid refrigerant pipe connected below the receiver is assumed to be an incompressible liquid refrigerant, and the amount of liquid refrigerant in the liquid refrigerant pipe is set to a constant known amount.
By adding up the amount of the liquid refrigerant and the amount of the gas refrigerant, the current total amount of the refrigerant to be detected for leakage is derived.
Based on the difference between the current total amount of refrigerant and the reference reference refrigerant amount in the refrigerant circulation pipe, the leakage of the refrigerant in the refrigerant circulation pipe is caused during the operation in which the refrigerant circulates in the refrigerant circulation pipe. , A method for detecting a refrigerant leak, which comprises continuously or intermittently detecting the refrigerant. The refrigerant leakage detection method according to claim 1, wherein the reference refrigerant amount is an initial refrigerant amount obtained by deriving the amount of refrigerant initially introduced into the refrigerant circulation pipe based on detection by the level sensor. In the low source side refrigeration cycle, a first pipe branched from a pipe connecting the liquid separator and the compressor unit, a second pipe branched from a pipe connecting the compressor unit and the cascade condenser, and the above. The first pipe and a protective container connected to the second pipe so as to be connected in parallel to the compressor unit are included.
The feature is that the amount of refrigerant in the first and second pipes and in the protective container is calculated based on the internal pressure of the protective container measured by the pressure gauge provided in the protective container and included in the total amount of refrigerant. The refrigerant leakage detection method according to claim 1 or 2. The low source side refrigeration cycle includes a first pressure regulating valve provided in the first pipe and a second pressure regulating valve provided in the second pipe.
Wherein during operation of the low-stage-side refrigeration cycle, the first, second pressure regulating valve is closed, the at the low-stage-side refrigeration cycle operation is stopped, and wherein the first, second pressure regulating valve is opened The refrigerant leakage detection method according to claim 3.

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