JPH0743052A - Cooler and sight glass for the cooler - Google Patents

Abstract

PURPOSE:To provide a cooler in which refrigerant leakage in a refrigerant circuit can be early detected. CONSTITUTION:A refrigerant circuit 13 of a cooler 1 is formed by sequentially annularly connecting a compressor 3, a condenser 4, a liquid reservoir 6, an expansion valve 9a, an evaporator 11a, etc., via a tube 12. A predetermined amount of refrigerant is sealed in the circuit 13. A lead-out tube 24 communicating with upper and lower parts of the reservoir 5 is provided. A sight glass 2 is provided at the tube 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device in which a refrigerant circuit is formed by sequentially connecting a compressor, a condenser, a liquid receiver, a pressure reducing device, an evaporator and the like in a ring, and a sight glass for such a cooling device. It is a thing.

[0002]

2. Description of the Related Art Conventionally, a cooling device used in a showcase or an air conditioner forms a refrigerant circuit by sequentially connecting a compressor, a condenser, a liquid receiver, a pressure reducing device, an evaporator, etc. in an annular shape through pipes. At the same time, a predetermined amount of refrigerant is enclosed in the refrigerant circuit. Then, when the compressor is operated, the refrigerant is compressed into a high-temperature high-pressure gaseous state and flows into the condenser. The refrigerant radiates heat in the condenser, and after being condensed and liquefied, it is once received by the liquid receiver. The liquid refrigerant stored in the liquid receiver is drawn out from the lower part of the liquid receiver, reduced in pressure, and supplied to the evaporator. In the evaporator, the liquid refrigerant after being depressurized evaporates, and at that time, heat is absorbed from the surroundings to exert a cooling effect.

By the way, when the refrigerant leaks from the refrigerant circuit and the amount of the refrigerant in the refrigerant circuit becomes insufficient, the liquid refrigerant in the receiver is depleted, and the refrigerant from the receiver to the decompression device is eventually exhausted. Flash gas (foam) comes to be generated. In such a state, a sufficient cooling medium is not supplied to the evaporator, so that the cooling capacity is significantly reduced.

Therefore, conventionally, a sight glass is provided in the pipe on the outlet side of the liquid receiver. This sight glass has glass on one side, and an indicator with a chemical substance called a moisture indicator is attached inside, and the state of the refrigerant passing through the inside is visually confirmed through the glass and flashed. It was configured to detect the generation of gas.

[0005]

However, with such a method, the decrease of the refrigerant can be detected only when the flash gas is generated in the sight glass. Therefore, there is a problem that it is not possible to detect the refrigerant leakage in a small amount of steps, and it is a countermeasure after the liquid refrigerant is exhausted in the receiver, so that the cooling capacity is completely lost and it is too late. It was

Further, conventionally, there is no method other than visually confirming the generation of flash gas in the sight glass, which complicates the management work by the user and detects a sudden decrease in refrigerant depending on the timing. There was also a problem that it was very difficult to do.

The present invention has been made to solve the above-mentioned conventional technical problems, and an object of the present invention is to provide a cooling device capable of detecting a refrigerant leak in a refrigerant circuit at an early stage. .

Another object of the present invention is to provide a cooling device that automates the detection of refrigerant leakage in a refrigerant circuit, and at the same time, provide a suitable sight glass for the cooling device.

[0009]

That is, the cooling device 1 according to the first aspect of the present invention is configured so that the compressor 3, the condenser 4, the liquid receiver 6, the pressure reducing device (expansion valve) 9a, the evaporator 11a and the like are connected to the pipe 12. And the refrigerant circuit 13 is sequentially connected in a circular shape by means of the above to form a refrigerant circuit 13, and a predetermined amount of refrigerant is enclosed in the refrigerant circuit 13, and a withdrawal pipe 24 communicating with the upper and lower portions of the liquid receiver 6
And the sight glass 2 provided in the pull-out pipe 24.

The cooling device 1 according to the second aspect of the present invention includes a compressor 3, a condenser 4, a liquid receiver 6, and a pressure reducing device (expansion valve) 9a.
Further, the refrigerant circuit 13 is formed by sequentially connecting the evaporator 11a and the like in an annular shape through the pipe 12, and a predetermined amount of refrigerant is sealed in the refrigerant circuit 13. The refrigerant circuit 13 is provided on the outlet side of the liquid receiver 6. The sight glass 2 provided in the pipe 12 and provided with a pair of transparent walls (glass) 17, 17 facing each other with a refrigerant passing through the inside, and a light emitting element (light emitting diode) facing each other with both transparent walls sandwiched therebetween. ) 28 and a light receiving element (photodiode) 27, and a control means (control device) 31;
The refrigerant circuit 13 is provided with a refrigerant charging device 32 for charging the refrigerant, and the control means detects generation of flash gas in the sight glass 2 based on the light receiving state of the light receiving element, and the refrigerant charging device 32 causes the refrigerant circuit. A predetermined amount of refrigerant is replenished into the inside of 13.

Further, the sight glass of the invention of claim 3 is
The main body 16 is connected to the piping of the cooling device 1.
And the connecting portions 18, 1 formed at the both ends of the main body 16.
8, a transparent portion 21 penetrating in a direction intersecting with the passage 19, and a pair of transparent walls (glass) 17 and 17 facing each other by closing both ends of the transparent portion 21.
And is equipped with.

[0012]

According to the cooling device 1 of the first aspect of the invention, the liquid receiver 6 for storing the liquid refrigerant condensed in the condenser 4 is provided with the withdrawing pipe 24 communicating with the upper and lower parts thereof. Since the sight glass 2 is provided in the drawer tube 24, the liquid surface of the refrigerant in the liquid receiver 6 appears in the sight glass 2. By confirming the decrease in the liquid level in the sight glass 2, it becomes possible to detect the refrigerant leakage from the refrigerant circuit 13 before the liquid refrigerant in the liquid receiver 6 is exhausted. Therefore, it becomes possible to take measures such as replenishment at an early stage when the refrigerant leakage is small.

According to the cooling device 1 of the second aspect of the invention, when the refrigerant leaks from the refrigerant circuit 13 and the liquid refrigerant in the receiver 6 is depleted, the outlet of the receiver 6 Side piping 1
The flash gas is generated in the refrigerant passing through the sight glass 2 provided in the No. 2. The sight glass 2 includes a pair of transparent walls facing each other with a refrigerant passing through the inside therebetween,
Further, a light emitting element and a light receiving element facing each other are provided at positions sandwiching these transparent walls, and when such a flash gas is generated, the amount of light reaching from the light emitting element to the light receiving element is blocked by the bubbles. The control means detects the generation of flash gas in the sight glass 2 based on the change in the light receiving state of the light receiving element, and replenishes the refrigerant circuit with a predetermined amount of the refrigerant by the refrigerant refilling device 32, so that the leakage of the refrigerant can be dealt with quickly. It is possible to maintain the cooling capacity, and automation can significantly simplify the user's management work.

Further, in the sight glass 2 for a cooling device according to the third aspect of the present invention, the transparent portion 21 penetrating in the direction intersecting with the passage 19 formed in the main body 16 and both ends of the transparent portion 21 are closed to be opposed to each other. A pair of transparent walls (glass) 17, 17 facing each other
Since it is provided with, the connection portions 18 at both ends of the passage are connected to the pipe 12 of the cooling device 1, which is suitable for carrying out the present invention.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a refrigerant circuit diagram of a cooling device 1 of the present invention, and FIG. 2 shows a vertical side view of a sight glass 2 of the present invention. The cooling device 1 is for cooling the interior of a low temperature open showcase (not shown) installed in, for example, a supermarket, and includes a compressor 3, a condenser 4, a liquid receiver 6,
Dryer 7, sight glass 2 of the present invention, a plurality of solenoid valves 8a, 8b, expansion valves 9a, 9b as pressure reducing devices,
A well-known refrigerant circuit 13 is formed by sequentially connecting the evaporators 11a and 11b in an annular shape through a pipe 12.

The solenoid valve 8a, expansion valve 9a and evaporator 1
1a, the solenoid valve 8b, the expansion valve 9b and the evaporator 11b respectively form a series circuit and are connected in parallel to the refrigerant circuit 13 on the outlet side of the sight glass 2, and each series circuit is a low temperature open showcase not shown. And the inside of the refrigerator is cooled by each of the evaporators 11a and 11b. Then, in the refrigerant circuit 13, a predetermined amount of refrigerant (for example, R-2
2, R-134a, etc.) are enclosed, and when the compressor 3 is operated, the high-temperature and high-pressure gas refrigerant compressed and discharged from the discharge side 3D of the compressor 3 flows into the condenser 4.

The high temperature gas refrigerant flowing into the condenser 4 is cooled there by an air cooling method or a water cooling method and radiates heat to be condensed and liquefied. The liquid refrigerant condensed in the condenser 4 then flows into the liquid receiver 6 and is temporarily stored therein. The liquid receiver 6 has a tank shape, and the liquid refrigerant flows out from the outlet side pipe 12 connected to the lower surface of the liquid receiver 6 and reaches the sight glass 2 through the dryer 7.

As shown in FIG. 2, the sight glass 2 is composed of a main body 16 made of brass, for example, and a pair of disk-shaped transparent glasses 17, 17 as transparent walls. A passage 19 through which the refrigerant flows is formed in the main body 16,
Connection part 1 with thread grooves on the outer surface at both ends of the body 16
8 and 18 are formed, and at this connecting portion 18, a passage 19 is formed.
Is open. Furthermore, a passage 19 is provided in the center of the main body 16.
A transparent portion 21 having a circular cross section is formed so as to penetrate in a direction orthogonal to the transparent glass 17 and the transparent glass 17 is formed in the transparent portion 2.
The sealing material 22, 2 is attached to the main body 16 so as to close both ends of 1.
Mounted via 2, whereby glass 17, 1
Reference numeral 7 is a relative resistance, and sandwiches the refrigerant passing through the passage 19.

The sight glass 2 is connected to the refrigerant circuit 13 by connecting the pipes 12 to the connecting portions 18 on both sides with the see-through portion 21 in the vertical direction. And
The liquid refrigerant passing through the dryer 7 is the glass 17 of the sight glass 2,
It passes through the passage 19 between 17 as shown by the solid line arrow in FIG. 2, and branches to reach each solenoid valve 8a, 8b. The solenoid valves 8a and 8b are controlled to open and close based on the internal temperature of the open showcase, and when the solenoid valves 8a and 8b are opened, the liquid refrigerant expands the expansion valve 9a and
Alternatively, after the pressure is reduced by 9b, the evaporator 11a or 1
1b respectively and it evaporates. The temperature of the evaporators 11a and 11b decreases due to the endothermic action that occurs at this time, and the cold air cooled by the low-temperature evaporators 11a and 11b is circulated in the open showcases and the insides are cooled. It Then, the low-temperature gas refrigerants that have exited from the evaporators 11a and 11b merge and pass through the pipe 12 to the suction side 3
Return from S to the compressor 3.

On the other hand, a withdrawal pipe 24 communicating with the upper and lower parts of the liquid receiver 6 is attached to the side surface of the liquid receiver 6,
The sight glass 2 similar to that described above is interposed in the pull-out pipe 24. In this case, the sight glass 2 has a connecting portion 18,
18 is the vertical direction, for example, from the bottom of the receiver 6 1/3
The pull-out pipes 24 are connected to each other so that the glass 17 is located there.

On the other hand, a photodiode 27 as a light receiving element and a light emitting diode 28 as a light emitting element are arranged above and below the sight glass 2 connected to the pipe 12 on the downstream side of the dryer 7. The photodiode 27 and the light emitting diode 28 face each other with the glasses 17 and 17 of the sight glass 2 sandwiched therebetween, whereby the light emitted from the light emitting diode 28 passes through the glass 17 as indicated by the broken line arrow in FIG. Then, the refrigerant flowing in the see-through portion 21 is further transmitted, the glass 17 is transmitted again, and the photodiode 27 receives the light.

The light emitting diode 28 and the photodiode 27 are connected to a control device 31 as control means, and the control device 31 causes the light emitting diode 28 to emit light, for example, at a predetermined sampling cycle. Also,
The refrigerant charging device 3 C of the compressor 3 is connected to the refrigerant charging device 32.
The refrigerant charging device 32 is configured to replenish the refrigerant circuit 13 with refrigerant in response to a command from the control device 31.

With the above configuration, the extraction pipe 24 of the liquid receiver 6
The liquid level of the refrigerant stored in the liquid receiver 6 appears in the see-through portion 21 of the sight glass 2 provided in the. Then, for some reason, the refrigerant leaks from the refrigerant circuit 13,
When the amount of the refrigerant in the refrigerant circuit 13 starts to decrease, the liquid level of the see-through portion 21 in the sight glass 2 also decreases in accordance with the liquid level decrease in the liquid receiver 6, so that this liquid level decrease is caused by the glass 17, 17.
By visually confirming through the refrigerant circuit 13
It is possible to detect the leakage of the refrigerant.

Therefore, a small amount of refrigerant leakage can be detected, and a rapid refrigerant leakage can be detected at an early stage, that is, before the liquid refrigerant in the liquid receiver 6 is exhausted. It is possible to take measures such as replenishing the refrigerant.

When the refrigerant leak is not detected at such an early stage and the refrigerant leak continues and the liquid refrigerant in the receiver 6 is depleted, it is connected to the pipe 12 on the outlet side of the receiver 6. The flash gas is generated in the refrigerant passing through the passage 19 of the sight glass 2 thus formed. When the flash gas is generated, the amount of light that is blocked by the bubbles and reaches the photodiode 27 from the light emitting diode 28 decreases. Control device 3
1 detects the generation of flash gas in the sight glass 2 due to the change (decrease) in the light receiving state of the photodiode 27, and issues a command to the refrigerant charging device 32 to replenish the refrigerant circuit 13 with a predetermined amount of refrigerant.

Therefore, the depletion of the liquid refrigerant in the receiver 6 due to the refrigerant leakage is automatically detected, and the refrigerant is quickly and automatically filled, so that the predetermined cooling capacity can be continuously maintained thereafter. As a result, the user's management work can be significantly simplified as compared with the conventional method of visually confirming the flash gas.

In the embodiment, the glasses 17 and 1 facing each other are used.
Although the liquid level of the liquid receiver 6 is detected by the sight glass 2 provided with 7, the sight glass is not limited to this, and the liquid level of the liquid receiver 6 is detected only by one face glass. It doesn't matter. Further, although the present invention is applied to the cooling device of the open showcase in the embodiment, the present invention is not limited to this, and the present invention is also effective to a refrigerator and other air conditioners.

[0028]

As described in detail above, according to the invention of claim 1, the liquid receiver for storing the liquid refrigerant condensed in the condenser,
A draw-out pipe communicating with the upper part and the lower part is provided.Since a sight glass is provided in this draw-out pipe, the liquid level of the refrigerant in the receiver appears in the sight glass, and the liquid level in this sight glass decreases. By confirming, it becomes possible to detect the refrigerant leakage from the refrigerant circuit before the liquid refrigerant in the liquid receiver is exhausted. Therefore, it is possible to take measures such as replenishment at an early stage when the refrigerant leakage is small.

According to the second aspect of the present invention, when the refrigerant leaks from the refrigerant circuit and the liquid refrigerant in the receiver is depleted, it is provided in the outlet side pipe of the receiver. Flash gas is generated in the refrigerant passing through the sight glass, but the sight glass is provided with a pair of transparent walls facing each other with the refrigerant passing through the inside interposed therebetween, and further, the positions sandwiching these transparent walls are relative to each other. The light emitting element and the light receiving element facing each other are provided, and when the flash gas is generated and the amount of light reaching the light receiving element from the light emitting element is blocked by the bubbles, the control means changes the light receiving state of the light receiving element. The generation of flash gas in the sight glass is detected, and a predetermined amount of refrigerant is automatically replenished in the refrigerant circuit by the refrigerant filling device.
Therefore, it is possible to quickly respond to refrigerant leakage and maintain the cooling capacity, and it is possible to significantly simplify the user's management work.

Further, according to the invention of claim 3, the sight glass is penetrated in a direction intersecting with a passage formed in the main body, and a pair of opposing portions are formed by closing both ends of the sight portion. Since the transparent wall is provided, it is suitable for carrying out the invention described above by connecting to the piping of the cooling device at the connecting portions at both ends of the passage.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a cooling device of the present invention.

FIG. 2 is a vertical sectional side view of the sight glass of the present invention.

[Explanation of symbols]

 1 Cooling Device 2 Sight Glass 3 Compressor 4 Condenser 6 Liquid Receiver 9a Expansion Valve 11a Evaporator 12 Piping 13 Refrigerant Circuit 16 Main Body 17 Glass 18 Connection 19 Passage 21 Sight 24 24 Extraction Tube 27 Photodiode 28 Light Emitting Diode 31 Control Device 32 Refrigerant charging device

Claims (3)

[Claims] 1. A refrigerant circuit is formed by sequentially connecting a compressor, a condenser, a liquid receiver, a decompression device, an evaporator, etc. in an annular shape by pipes, and a predetermined amount of refrigerant is enclosed in the refrigerant circuit. A cooling device comprising: a drawing pipe communicating with an upper part and a lower part of the liquid receiver; and a sight glass provided in the drawing pipe. 2. A refrigerant circuit is formed by sequentially connecting a compressor, a condenser, a liquid receiver, a decompression device, an evaporator, etc. in an annular shape with pipes, and a predetermined amount of refrigerant is enclosed in the refrigerant circuit. In a cooling device comprising: a sight glass provided in a pipe on the outlet side of the liquid receiver, the sight glass having a pair of transparent walls facing each other with a refrigerant passing through the inside interposed therebetween, and the sight glass having the transparent walls interposed therebetween. Control means having a light-emitting element and a light-receiving element facing each other, and a refrigerant charging device for charging the refrigerant in the refrigerant circuit, the control means, in the sight glass depending on the light-receiving state of the light-receiving element. A cooling device which detects the generation of flash gas and replenishes a predetermined amount of refrigerant in the refrigerant circuit by the refrigerant charging device. 3. In a sight glass connected to piping of a cooling device, a main body, a passage formed in the main body, opened at connection portions at both ends, and a see-through portion penetrating in a direction intersecting with the passage, A sight glass for a cooling device, which comprises a pair of transparent walls that are opposed to each other by closing both ends of a see-through portion.