JP2002286333A - Refrigeration equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a refrigeration apparatus that can quickly and accurately detect a refrigerant leak regardless of seasonal changes and an initial refrigerant charge amount. The refrigerating device includes a level sensor (refrigerant discharge pipe, etc.) for detecting a liquid level of a refrigerant stored in a liquid reservoir in a refrigerant circuit, and a pressure for detecting a refrigerant pressure in the liquid reservoir. A sensor 19, a temperature sensor 20 for detecting the temperature of the refrigerant in the liquid reservoir 3, and a mass of the refrigerant in the liquid reservoir when the refrigerant in the refrigerant circuit is recovered in the liquid reservoir 3 by performing a pump-down operation at regular time intervals, It is calculated based on the values detected by the level sensor, the pressure sensor 19, and the temperature sensor 20, and the calculated refrigerant mass in the reservoir is compared with the refrigerant mass in the reservoir calculated at the time of the previous pump down. A refrigerant leak detection unit (means) 21 for detecting leakage of the refrigerant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system using a refrigerant such as chlorofluorocarbon gas, and more particularly, to a refrigeration system having a large amount of enclosed refrigerant and requiring detection of refrigerant leakage.

[0002]

2. Description of the Related Art FIG. 8 shows a schematic configuration of a conventional refrigerating apparatus disclosed in Japanese Patent Application Laid-Open No. 10-103820.
In the figure, 1 is a compressor for compressing the refrigerant, 2 is a condenser for condensing the compressed refrigerant, 3 is a liquid reservoir for temporarily storing the condensed refrigerant, 8 is an electromagnetic valve that can shut off the refrigerant circuit, 4 is an expansion valve for expanding the liquid refrigerant, 5 is an evaporator for evaporating the refrigerant, 12 is an auxiliary tank for measuring the refrigerant level of the liquid reservoir 3, 16a and 16b are the auxiliary tank 12 and the liquid reservoir 3
Is a float type level sensor for measuring the refrigerant level, 27 is a float that moves up and down according to the liquid level, and 28 is a reed switch for detecting a normal liquid level and a leak. I have. The refrigerant circuit of such a refrigeration apparatus includes the above-described compressor 1, condenser 2, liquid reservoir 3,
The solenoid valve 8, the expansion valve 4, and the evaporator 5 are connected to the pipes 7, 9, 10, and 6.
Are sequentially connected in a ring shape.

[0003] In FIG. 8, a low-temperature low-pressure refrigerant gas is compressed by a compressor 1 to become a high-temperature high-pressure refrigerant gas and flows into a condenser 2, where the refrigerant is condensed and liquefied by cooling with outside air or cold water. Stored in 3. The stored liquid refrigerant is sent to the expansion valve 4 through the electromagnetic valve 8, the pressure is reduced according to the degree of opening of the expansion valve 4, expanded to a low temperature and low pressure, and flows into the evaporator 5. In the evaporator 5, the low-temperature and low-pressure liquid refrigerant removes heat from the coolant and evaporates, and is circulated to the compressor 1.

In this refrigeration system, when the solenoid valve 8 is closed manually or by a timer at a predetermined cycle, a pump-down operation is performed, and the refrigerant in the refrigeration cycle is stored in the liquid reservoir 3. Here, the float 27 of the float type level sensor 26 measures the refrigerant level in the auxiliary tank 12.
At this time, when there is no refrigerant leak in the refrigerant circuit and the operation is normal, the float 27 is at the position of the reed switch 28, and the float 27 and the reed switch 28 are in contact with each other, and no leak signal is output. On the other hand, when a refrigerant leak occurs in the refrigerant circuit, the amount of refrigerant in the liquid reservoir after pump down is reduced, and the float 27 is at a position where it does not contact the reed switch. Accordingly, it is determined that the refrigerant is leaking, and a refrigerant leak detection signal is output.

[0005]

Conventionally, as a refrigerant, R
Although specific Freon gas containing chlorine such as -22 has been widely used, it has been found that leaked refrigerant gas causes destruction of the ozone layer and has a large effect on the environment. In recent years, a refrigerating apparatus using a refrigerant such as R404A containing no chlorine has been developed, but the price of the refrigerant such as R404A is extremely high. Therefore, when the refrigerant leaks, the cost of the refrigerant to be additionally charged becomes enormous, and the burden on the user and the construction shop increases. Further, in a refrigerator using a natural refrigerant such as propane, there is a danger that the leaked refrigerant may ignite or explode. Therefore, development of safe refrigerant leak detecting means has been desired.

In the above-described conventional refrigeration apparatus, when the outside air temperature around the liquid reservoir changes with the season, the density of the refrigerant in the liquid reservoir and the liquid pipe changes. When the density of the refrigerant changes in this way, the volume of the refrigerant in the liquid reservoir changes during the pump-down operation even if the actual refrigerant amount (mass) in the refrigerant circuit does not change, and the liquid level in the liquid reservoir significantly increases. Change. Then, when the liquid level significantly changes, it is considered that the float descends to a position where it is determined that there is a leak,
Even when there is no refrigerant leak, it may be erroneously detected that a leak is present.

[0007] The length of the piping connecting the liquid reservoir to the expansion valve or the evaporator greatly varies depending on the layout of the store or the method of use by the customer. As described above, since the density of the liquid refrigerant changes with the change in the outside air temperature, the refrigerant volume stored in the pipe connecting the liquid reservoir and the evaporator during the pump-down operation changes according to the outside air temperature. Therefore, the refrigerant volume in the liquid reservoir, which is the amount obtained by subtracting the refrigerant volume in the piping from the total refrigerant volume,
It changes according to the change in outside air temperature. When the volume of the refrigerant in the liquid reservoir changes, the liquid level changes. Therefore, even if there is no leakage, there is a risk of erroneous detection of determining that the refrigerant is leaking.

Further, the above float sensor cannot linearly detect the liquid level during the pump down operation, and is very expensive. As described above, the layout of a store or the like greatly changes depending on the customer's usage method, and thus the amount of refrigerant to be initially charged also changes for each store. For this reason, in the above-mentioned float type sensor, it is necessary to determine the normal liquid level at the time of trial operation and change the position of the reed switch.

The present invention solves the above-mentioned problems, and is not affected by a change in the outside air temperature due to seasonal changes, is not affected by an initial refrigerant charging amount, is low-cost, is early accurate, and requires human labor. It is an object of the present invention to provide a refrigeration apparatus capable of detecting a refrigerant leak without any problem.

[0010]

In order to achieve the above object, a refrigeration apparatus according to the present invention comprises a compressor, a condenser, a liquid reservoir,
An apparatus comprising a refrigerant circuit formed by sequentially connecting evaporators and the like by pipes, wherein the level sensor detects a liquid level of a refrigerant stored in a liquid reservoir, and detects a refrigerant pressure in the liquid reservoir. A pressure sensor, a temperature sensor for detecting the temperature of the refrigerant in the reservoir, and a mass sensor for the refrigerant in the reservoir when the refrigerant in the refrigerant circuit is recovered in the reservoir by performing a pump-down operation at regular time intervals. Calculate based on the pressure sensor and the value detected by the temperature sensor, and compare the calculated refrigerant mass in the reservoir with the refrigerant mass in the reservoir calculated at the time of the previous pump-down to detect leakage of the refrigerant from the refrigerant circuit. And a refrigerant leak detecting means for detecting.

[0011] In the above structure, an operation command output section for outputting a command signal relating to the pump-down operation at regular time intervals is provided, and the solenoid valve which is opened and closed by the command signal from the operation command output section is provided with a liquid refrigerant in a liquid reservoir. It is located immediately after the exit.

In each of the above structures, the level sensor is provided at each of a plurality of refrigerant outlet pipes arranged at predetermined intervals in the height direction and connected to the side surface of the liquid reservoir. Consisting of a decompression device for refrigerant decompression, a heater provided in each refrigerant outlet tube to heat the refrigerant from the decompression device, and a temperature detector provided in each refrigerant outlet tube and detecting the temperature of the refrigerant from the heater. Is what is being done.

Further, in each of the above constructions, the level sensor comprises a float floating on the liquid surface of the refrigerant stored in the liquid reservoir, and a voltage output section for outputting a voltage corresponding to the height position of the float. Is what it is.

In addition, an auxiliary tank having a level sensor is provided, the auxiliary tank and the liquid reservoir are connected by a communication pipe, and an on-off valve for opening and closing the communication pipe is provided in the communication pipe.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 of the Invention FIG. 1 is a configuration diagram of a refrigeration apparatus showing Embodiment 1 of the present invention. 8, the basic configuration of the refrigerant circuit is almost the same as that of the conventional device shown in FIG. That is, 1 is a compressor for compressing the refrigerant, 2 is a condenser for condensing the compressed refrigerant, 3 is a liquid reservoir for temporarily storing the condensed refrigerant, 8 is an electromagnetic valve that can shut off the refrigerant circuit, 4 is An expansion valve for expanding the liquid refrigerant, 5 an evaporator for evaporating the refrigerant, 11 a low-pressure switch, 12 an auxiliary tank for measuring the liquid level of the refrigerant in the liquid reservoir 3, 16a and 16b an auxiliary tank 12 and the liquid. Communication pipes 17a, 176b for communicating the reservoir 3 at the top and bottom, respectively;
Are open / close valves for shutting off the communication pipes 16a and 16b, respectively;
Reference numeral 8 denotes an electromagnetic valve that shuts off the flow of the refrigerant from the auxiliary tank 12 to the pipe 10, and is closed during normal operation. Also,
Reference numeral 19 denotes a pressure sensor for detecting the pressure of the refrigerant in the auxiliary tank 12, and reference numeral 20 denotes a temperature sensor for detecting the temperature of the refrigerant in the auxiliary tank 12. The solenoid valve 8 is provided in the pipe 7 immediately after the liquid refrigerant outlet at the bottom of the liquid reservoir 3 and is opened and closed by a command signal from an operation command output unit 30. The operation command output unit 30 outputs a command signal related to the pump-down operation at regular time intervals.

FIG. 2 is a detailed view around the auxiliary tank 12. In the figure, reference numeral 21 denotes a refrigerant leak detecting unit (an example of a refrigerant leak detecting means according to the present invention) for detecting a refrigerant leak and controlling an electromagnetic valve, and 22, 22, and 22 are arranged at predetermined intervals in a height direction and have an auxiliary tank. 3 connected to 12 sides
The refrigerant outlet pipes 13 are decompression devices for depressurizing the refrigerant provided on the refrigerant outlet pipes 22, respectively.
2, a heater for heating the refrigerant from the pressure reducing device 13; and 15, a temperature detecting unit provided for each refrigerant outlet pipe 22 for detecting the temperature of the refrigerant passing through the heater 14.

Next, the operation will be described. 1 and 2, a low-temperature and low-pressure refrigerant gas is compressed by a compressor 1 to become a high-temperature and high-pressure refrigerant gas and flows into a condenser 2. The condenser 2 is cooled by outside air or cold water and condensed and liquefied. It is stored in pool 3. The stored liquid refrigerant is supplied to the expansion valve 4 via the electromagnetic valve 8.
The pressure is reduced according to the degree of opening of the expansion valve 4, expanded to a low temperature and low pressure, and flows into the evaporator 5. In the evaporator 5, the low-temperature and low-pressure liquid refrigerant evaporates by removing heat from the object to be cooled.
Circulated to

Here, when the solenoid valve 8 is closed by a timer of the operation command output unit 30 or manually at a predetermined cycle,
The pump-down operation is performed, and the refrigerant in the refrigeration cycle is stored in the liquid reservoir 3. By closing the solenoid valve 8,
The pressure in the pipe 10 decreases, the low pressure switch 11 closes, and the operation of the compressor 1 is stopped. When the refrigerant leak detection unit 21 detects the signal S1 indicating that the compressor 1 has stopped, the refrigerant leak detection unit 21 outputs a command signal for opening the solenoid valve 18. When the solenoid valve 18 is opened, the gas refrigerant and the liquid refrigerant in the auxiliary tank 12 flow into the refrigerant outlet pipe 22. At the same time, the refrigerant leak detector 21 outputs an energization signal to cause the heater 15 to generate heat. The pressure P1 refrigerant flowing from the auxiliary tank 12 into the refrigerant outlet pipe 22 is depressurized by the decompression device 13, and decreases to the pressure P2 as shown in FIG. After the refrigerant is heated by the heater 14, the electromagnetic valve 18
Through the pipe 10 on the suction side.

At this time, if the state of the refrigerant in the refrigerant outlet pipe 22 is liquid, the temperature detected by the temperature detecting unit 15 is t1 from the Mollier diagram of FIG. Also, the refrigerant outlet pipe 2
If the state of the refrigerant in 2 is gas, the temperature detected by the temperature detecting unit 15 is t3, which is higher than t1, according to the Mollier diagram of FIG. At this time, the temperature detected by the temperature detection unit 15 of the refrigerant outlet pipe 22 connected to a position lower than the liquid level of the refrigerant in the auxiliary tank 12 is t1, and the refrigerant is connected to a position above the liquid level of the refrigerant in the auxiliary tank 12. The temperature detected by the temperature detector 15 of the refrigerant outlet pipe 22 is t3. From the temperature difference, the height of the refrigerant discharge pipe 22 taken out from the position where the temperature changes is the liquid level of the refrigerant in the auxiliary tank 12, and thus the liquid level can be detected. The solenoid valve 18 is closed again when the temperature detection by the temperature detection unit 15 is completed. That is, the structure including the refrigerant outlet pipes 22, 22, 22, the pressure reducing devices 13, 13, 13, the heaters 14, 14, 14, and the temperature detectors 15, 15, 15 is used for the liquid level of the refrigerant stored in the liquid reservoir. This is an example of a level sensor that detects a level.

FIG. 4 shows a flow for judging a refrigerant leak. Refrigerant leak detector 21 detects the pressure and temperature of the refrigerant in auxiliary tank 12 by sensors 19 and 20, respectively. The refrigerant leak detection unit 21 calculates the refrigerant volume in the liquid reservoir 3 from the liquid level detected as described above, and
The density of the refrigerant in the liquid reservoir 3 is calculated from the pressure and the temperature detected at 0. After that, the refrigerant mass M1 in the liquid reservoir 3 is calculated by multiplying the refrigerant volume in the liquid reservoir 3 by the refrigerant density.
The refrigerant mass calculated in this way is temporarily stored in a storage unit (not shown) of the refrigerant leak detection unit 21 for use in the next calculation. On the other hand, the refrigerant leak detector 2
1 compares the refrigerant mass M0 in the liquid reservoir 3 at the time of the previous pump-down operation with the refrigerant mass M1 calculated this time. The refrigerant leak detector 21 calculates the refrigerant mass M1 calculated this time.
Is determined to be a refrigerant leak when it is determined that it is smaller than the refrigerant mass M0 by the predetermined amount H at the time of the previous pump-down operation, and the refrigerant leak signal S2 is output. Then, after the refrigerant leak signal S2 is output, a signal for opening the electromagnetic valve 8 is output, whereby the electromagnetic valve 8 is opened, the low-pressure switch 11 is opened, and the operation of the compressor 1 is restarted. That is, the refrigerant leak detection unit 21 determines the mass M1 of the refrigerant in the liquid reservoir when the refrigerant in the refrigerant circuit is recovered in the liquid reservoir 3 by performing the pump-down operation at regular time intervals. , And compares the calculated refrigerant mass M1 in the reservoir with the refrigerant mass M0 in the reservoir calculated at the time of the previous pump down. The leakage of refrigerant from the circuit is detected.

On the other hand, when the difference between the refrigerant mass M0 at the time of the previous pump-down operation and the refrigerant mass M1 calculated this time is within a predetermined amount H, the refrigerant leak detection unit 21 does not output the refrigerant leak signal S2 and the solenoid valve 8 is output only. When the solenoid valve 8 is opened, the low pressure switch 11 is opened and the operation of the compressor 1 is restarted.

As described above, according to the first embodiment, the pump down is performed at regular time intervals, the refrigerant volume in the liquid reservoir is calculated from the liquid level of the auxiliary tank, and the pressure and temperature in the auxiliary tank are calculated. By calculating the density of the refrigerant in the liquid reservoir, the mass of the refrigerant in the liquid reservoir can be detected. By comparing the detected refrigerant mass in the liquid reservoir with the previously detected refrigerant mass, if the refrigerant mass has decreased by a certain amount or more, it can be determined that a refrigerant leak has occurred and an alarm can be output. For this reason, the refrigerant leak can be accurately and promptly performed without human intervention regardless of the change in the outside air temperature due to the seasonal change and the initial amount of the refrigerant charged according to the floor layout of the customer. In addition, since the solenoid valve 8 is mounted near the outlet of the liquid reservoir 3, the leakage of the refrigerant can be accurately detected without being affected by the length of the liquid pipe which varies depending on the floor layout of the customer. As a result, it is possible to eliminate the waste of charging the additional refrigerant without releasing the expensive refrigerant to the atmosphere, to prevent a decrease in the refrigeration capacity due to a shortage of the refrigerant amount, and to cause the products in the showcase and the warehouse to become uncooled. Can be prevented. The impact on the environment such as depletion of the ozone layer can be reduced, and safety can be ensured by preventing fire, explosion, lack of oxygen and other accidents. Further, since an expensive sensor is not used, a refrigerant leak detector can be provided at relatively low cost.

Further, the on-off valves 17a and 17b are provided in the communication pipes 16a and 16b for communicating the auxiliary tank 12 and the liquid reservoir 3, so that the auxiliary tank 12 can be removed. Later mounting is also possible. As shown in FIG. 5, it is also possible to omit the auxiliary tank 12 and directly connect the refrigerant outlet pipe 22 to the liquid reservoir 3.

Embodiment 2 of the Invention FIG. 6 is a configuration diagram of a refrigeration apparatus showing Embodiment 2 of the present invention. In the figure, reference numeral 23 denotes a float of a level sensor capable of linearly measuring the refrigerant level in the auxiliary tank 12, and 23a denotes a float 23.
A voltage output unit that slidably holds the vertical position and outputs a voltage corresponding to the height position of the float 23;
2 that electrically connects the refrigerant leak detection unit 25 to the
4. That is, the level sensor according to this embodiment includes the float 23, the voltage output unit 23a, and the lead wire 24.

Next, the operation will be described. As described above, the electromagnetic valve 8 is closed by the timer or the like of the operation command output unit 30 to perform the pump-down operation, and the refrigerant is stored in the liquid reservoir 3. The pump-down end signal S1 is output from the refrigerant leak detector 25.
, The voltage output unit 23a outputs the position of the float 23 in the auxiliary tank 12 as a voltage signal and transmits it to the refrigerant leak detection unit 25 via the lead wire 24. At the same time, the pressure and temperature in the auxiliary tank 12 are
9 and the temperature sensor 20. The refrigerant leak detection unit 25 calculates the liquid level from the obtained voltage signal,
The volume of the refrigerant stored in the liquid reservoir 3 is calculated. Then, the refrigerant leak detection unit 25 calculates the refrigerant mass in the liquid reservoir 3 by multiplying the calculated refrigerant volume by the refrigerant density in the auxiliary tank 12 calculated from the detected pressure and the detected temperature. The refrigerant mass calculated in this way is temporarily stored in a storage unit (not shown) of the refrigerant leak detection unit 25 for use in the next calculation. On the other hand, the refrigerant mass calculated this time is compared with the refrigerant mass in the reservoir calculated when the pump was last downed. As a result of the comparison by the refrigerant leak detection unit 25, when it is determined that the current refrigerant mass is smaller than the refrigerant mass at the time of the previous pump down operation by a certain amount or more, the refrigerant leak detection unit 25 determines that the refrigerant is a leak and the refrigerant leak signal S2 Is output. After the signal S2 is output, a signal for opening the solenoid valve 8 is output, so that the solenoid valve 8 is opened, the low-pressure switch 11 is opened, and the operation of the compressor 1 is restarted.

On the other hand, when the difference between the refrigerant mass at the time of the previous pump-down operation and the refrigerant mass calculated this time is within a certain amount, the refrigerant leak detector 25 does not output the refrigerant leak signal S2 and opens the solenoid valve 8. Outputs only the signal. When the solenoid valve 8 is opened, the low pressure switch 11 is opened, and the operation of the compressor 1 is restarted.

As described above, according to the second embodiment, the pump-down operation is performed at regular time intervals, the refrigerant volume in the liquid reservoir is calculated from the liquid level, and the liquid reservoir is calculated from the pressure and temperature in the auxiliary tank. The mass of the refrigerant in the liquid reservoir is calculated by detecting the density of the refrigerant in the liquid reservoir. By comparing the calculated refrigerant mass with the previously calculated refrigerant mass, if the refrigerant mass has decreased by a certain amount or more, it can be determined that a refrigerant leak has occurred and an alarm can be output. Therefore, regardless of the change in the outside air temperature due to the seasonal change and the initial amount of the refrigerant charged due to the floor layout of the customer or the like, the refrigerant can be leaked accurately and promptly without any manual operation. In addition, since the solenoid valve is mounted near the outlet of the liquid reservoir, the refrigerant leak can be accurately detected without being affected by the length of the liquid pipe that changes depending on the floor layout of the customer. As a result, the expensive refrigerant is not released to the atmosphere, the waste of charging the additional refrigerant can be eliminated, and a decrease in the refrigeration capacity due to the shortage of the refrigerant amount can be prevented, and the products in the showcase and the warehouse are not cooled. Can be prevented. In addition, effects on the environment such as depletion of the ozone layer can be reduced, and safety can be ensured by preventing fire, explosion, lack of oxygen, and the like. Also, since the liquid level can be directly measured by the float, even a minute amount of refrigerant leak can be accurately detected.

Further, the on-off valves 17a and 17b are provided in the communication pipes 16a and 16b communicating the auxiliary tank 12 and the liquid reservoir 3, so that the auxiliary tank 12 can be removed. Alternatively, after installing the refrigerator, the auxiliary tank 12
Can also be installed. On the other hand, as shown in FIG. 7, it is also possible to omit the auxiliary tank 12 and directly attach a float type level sensor to the liquid reservoir 3.

The liquid reservoir according to the present invention is not limited to the liquid reservoir 3 shown in the embodiment, but may be, for example, the liquid reservoir 3 and the auxiliary tank 12.
And the connection configuration of

[0031]

As described above, according to the refrigeration system of the present invention, the mass of the refrigerant in the liquid pool collected during the pump-down operation is calculated based on the values detected by the level sensor, the pressure sensor, and the temperature sensor. Then, the calculated refrigerant mass in the reservoir is compared with the refrigerant mass in the reservoir calculated at the time of the previous pump down, and if the refrigerant mass is reduced by a certain amount or more, for example, it is determined that the refrigerant is leaking and an alarm is output. This makes it possible to accurately and early detect the leakage of the refrigerant from the refrigerant circuit irrespective of the change in the outside air temperature due to the seasonal change and the initial amount of the refrigerant charged according to the floor layout of the customer, and without human intervention. be able to. As a result, it is not necessary to discharge the expensive refrigerant to the atmosphere, it is possible to eliminate waste of additionally filling the refrigerant, and it is possible to prevent a decrease in the refrigeration capacity due to a shortage of the refrigerant amount. As a result, it is possible to prevent temperature rise damage to items in the showcase and the warehouse. Besides,
Since the leakage of the CFC-based refrigerant can be prevented beforehand, the influence on the environment such as destruction of the ozone layer can be reduced. In addition, since leakage of the natural refrigerant can be prevented beforehand, safety can be ensured by preventing fire, explosion, lack of oxygen and the like.

Further, since the solenoid valve which is opened and closed by the command signal relating to the pump-down operation is disposed immediately after the liquid refrigerant outlet of the liquid reservoir, the electromagnetic valve is affected by the length of the liquid pipe which varies depending on the floor layout of the customer. There is no. Thereby, the leak of the refrigerant can be detected more accurately.

The liquid level of the refrigerant in the liquid reservoir is measured based on the values detected by the pressure reducing device, the heater, and the temperature detector provided in each of the plurality of refrigerant outlet pipes. Thus, the refrigerant leak detecting means can be provided relatively inexpensively without using an expensive sensor.

Furthermore, since a voltage corresponding to the height position of the float floating on the liquid surface of the refrigerant is output, the liquid surface level of the refrigerant can be measured more accurately, and even a minute amount of refrigerant leakage can be detected. Can be.

Further, by providing an opening / closing valve in the middle of a communication pipe communicating the auxiliary tank with the liquid reservoir, the auxiliary tank can be removed from the liquid reservoir, and the auxiliary tank can be attached after the refrigeration system is installed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a refrigeration apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a detailed view of an auxiliary tank and a refrigerant leak detector shown in FIG.

FIG. 3 is a principle diagram of a liquid level measuring method according to the first embodiment of the present invention.

FIG. 4 is a leak determination flowchart according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of another refrigeration apparatus according to Embodiment 1 of the present invention.

FIG. 6 is a schematic configuration diagram of a refrigeration apparatus according to Embodiment 2 of the present invention.

FIG. 7 is a schematic configuration diagram of another refrigeration apparatus according to Embodiment 2 of the present invention.

FIG. 8 is a schematic configuration diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

1 compressor, 2 condenser, 3 reservoir, 4 expansion valve, 5
Evaporator, 6 pipes, 7 pipes, 8 solenoid valves, 9 pipes, 1
0 piping, 11 low pressure switch, 12 auxiliary tank, 1
3 decompressor, 14 heater, 15 temperature detector, 16
a communication pipe, 16b communication pipe, 17a on-off valve, 17b
On-off valve, 18 solenoid valve, 19 pressure sensor, 20 temperature sensor, 21 refrigerant leak detection unit, 22 refrigerant outlet tube, 23 float, 23a voltage output unit, 24 lead wire, 25 refrigerant leak detection unit, 30 operation command output unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Nakata 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Hiromitsu Moriyama 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Isao Sakagami 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd.

Claims (5)

[Claims] 1. A refrigeration apparatus comprising a refrigerant circuit configured by connecting a compressor, a condenser, a liquid reservoir, an evaporator, and the like in sequence with a pipe, wherein a liquid level of the refrigerant stored in the liquid reservoir is provided. , A pressure sensor for detecting the pressure of the refrigerant in the liquid reservoir, a temperature sensor for detecting the temperature of the refrigerant in the liquid reservoir, The refrigerant mass in the reservoir when the refrigerant in the refrigerant circuit is recovered is calculated based on the values detected by the level sensor, the pressure sensor, and the temperature sensor, and the calculated refrigerant mass in the reservoir and the previous pump A refrigeration system comprising: refrigerant leak detection means for detecting leakage of refrigerant from the refrigerant circuit by comparing the refrigerant mass in the liquid pool calculated at the time of a down. 2. An operation command output unit for outputting a command signal relating to a pump-down operation at predetermined time intervals, wherein an electromagnetic valve which is opened and closed by a command signal from the operation command output unit is provided immediately after a liquid refrigerant outlet of a liquid reservoir. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is arranged. 3. A level sensor comprises a plurality of refrigerant outlet pipes arranged at predetermined intervals in a height direction and connected to a side surface of a liquid reservoir, and a pressure reducing device provided for each of the refrigerant outlet pipes for depressurizing the refrigerant. And a heater provided in each of the refrigerant outlet pipes to heat the refrigerant from the decompression device, and a temperature detector provided in each of the refrigerant outlet pipes and detecting the temperature of the refrigerant from the heater, The refrigeration apparatus according to claim 1 or 2, wherein 4. A level sensor comprising: a float floating on a liquid surface of a refrigerant stored in a liquid reservoir; and a voltage output unit for outputting a voltage corresponding to a height position of the float. The refrigeration apparatus according to claim 1 or 2, wherein 5. An auxiliary tank having a level sensor,
The said auxiliary tank and the liquid reservoir are connected by the communication pipe, The opening / closing valve which opens and closes the said communication pipe was provided in the middle of the said communication pipe, The Claim 1 characterized by the above-mentioned. Item 2. The refrigeration apparatus according to item 1.