JPH04257657A - Refrigerator/cold storage machine - Google Patents

Abstract

PURPOSE:To provide a freezer refrigerator for which the noise of a compressor at the time of re-starting is small, and trouble in operation of the compressor is not generated. CONSTITUTION:A connection line 6, which connects an oil reservoir tank 5 which is arranged at a position being higher than a compressor 3 and a discharge pipe 10 of the compressor 3, is provided on the suction side of the rotary type compressor 3 for a refrigerating cycle 2, and a capillary tube 7, of which the resistance to the circulation of a refrigerant gas is extremely large, is provided on the connection line 6, to constitute the title refrigerator/cold storage machine. When the compressor 3 stops, a refrigerator oil 9, which is stored in the oil reservoir tank 5 by flowing reversely through a suction pipe 4, returns to the compressor 3 through the capillary tube 7 and the discharge pipe 10. By this method, the quantity of the refrigerator oil 9 in the suction pipe 4 does not increase, and the quantity of the refrigerator oil 9 in the compressor 3 does not unnecessarily decrease. In the meantime, the high pressured refrigerant gas due to driving of the compressor 3 is prevented from reversely flowing to the oil reservoir tank 5, by the capillary tube 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator-freezer equipped with a predetermined refrigeration cycle, and more particularly to a refrigerator-freezer which is designed to reduce the noise of a rotary compressor constituting the refrigeration cycle.

0002

2. Description of the Related Art An example of the refrigeration cycle of the above-mentioned refrigerator-freezer is shown in FIG. Refrigeration cycle 2b shown in the figure
, when the compressor 3 is driven, the gaseous refrigerant pressurized by the compressor 3 moves in the direction shown by the solid arrow.
The refrigerant is guided from a discharge pipe 10, which is a refrigerant pipe 11, to a condenser 12, where it is cooled and becomes a liquid refrigerant while remaining at a high pressure. This refrigerant passes through the refrigerant pipe 11 and is led to the capillary tube 13 and is depressurized.
The latent heat of evaporation during evaporation in the evaporator 14 cools the inside of the refrigerator-freezer. The low-pressure refrigerant that has become a gas in the evaporator 14 returns to the compressor 3 through the suction pipe 4. In this way, the cooling capacity of the refrigeration cycle 2b depends on the refrigerant circulation capacity of the compressor 3. The capacity of the compressor 3 is generally necessary to lower the temperature of the food to a predetermined temperature, taking into consideration the cooling rate required when rapidly cooling the food stored in the refrigerator. It is set to about twice the capacity. Therefore, in the above-mentioned refrigeration cycle 2b, 100%
By turning ON/OFF the compressor 3, which is driven with a capacity of 1, the temperature inside the refrigerator is controlled. On the other hand, in recent years, rotary type compressors with low energy consumption and low noise, such as rotary type compressors that compress gas using a rolling piston that rotates within the main body, have been widely used as the compressor 3 of the refrigeration cycle 2b. This rotary compressor 3 is generally not equipped with a valve on its suction side that allows gas to flow only in the suction direction. The pressure will be relatively high. Therefore, when the compressor 3 is turned off when controlling the temperature inside the refrigerator, the high-pressure refrigerant gas inside the compressor 3 flows back into the low-pressure suction pipe 4 at that time. At the same time, the refrigerating machine oil 9 that lubricates the mechanical seal portion (not shown) of the compressor 3 also flows out into the suction pipe 4 along with the refrigerant gas and accumulates in the suction pipe 4. Here, the above suction pipe 4
Considering the case where the oil sump tank 5 for storing the refrigerating machine oil 9 from the suction pipe 4 is not provided, the refrigerating machine oil 9 will remain accumulated in the suction pipe 4 and will not be used the next time the compressor 3 is started. Sometimes, the refrigerating machine oil 9 in the suction pipe 4 flows into the compressor 3 all at once. Since this refrigerating machine oil 9 is in a liquid state, a greater load is placed on the compressor 3 than when compressing gas during normal operation. Thereby, the compressor 3
makes a loud noise when restarting. FIG. 7 shows an example of the noise generated when the refrigerating machine oil 9 is sucked into the suction pipe 4 all at once. The figure shows a sound pressure level curve with time domain plotted on the horizontal axis. In this case, in the compressor 3, a relatively large peak level P2 (79.9 dB) appears approximately 120 milliseconds after startup, and the subsequent sound pressure level decays exponentially with the passage of time. . That is, when this sound pressure level curve is converted into the frequency domain by frequency analysis, it can be seen that there is a peak in the high frequency domain caused by chattering of the rotor. Therefore,
Generally, an oil sump tank 5 is provided in the suction pipe 4,
Refrigerating machine oil 9 that has reached this oil sump tank 5 is accommodated therein. As a result, the amount of refrigerating machine oil 9 sucked into the compressor 3 at the time of restart is reduced, and the above-mentioned noise at the time of restart is reduced.

0003

[Problem to be Solved by the Invention] However, when the amount of oil in the oil sump tank 5 increases and becomes full due to repeated ON/OFF operations of the compressor 3, the oil sump tank 5 is no longer installed. If not, there will be a loud noise when restarting. On the other hand, since the refrigerating machine oil 9 from the suction pipe 4 is stored in the oil sump tank 5, the amount of oil in the compressor 3 decreases, which may cause problems in the operation of the compressor 3. For example, the mechanical seal portion may not be properly lubricated, resulting in an increased load and increased power requirements, or in the worst case scenario, the device may become inoperable. Therefore, it is an object of the present invention to provide a refrigerator-freezer that makes less noise when restarting the compressor and does not cause any trouble in the operation of the compressor.

0004

[Means for Solving the Problems] In order to achieve the above object, the main means adopted by the present invention is to provide a refrigerant pipe on the suction side of a rotary compressor constituting a predetermined refrigeration cycle. In a refrigerator-freezer having an oil sump tank for storing lubricating oil from the compressor in a channel, a connecting pipe connecting the oil sump tank and the discharge side of the compressor is provided, and the connecting pipe is connected to the Adjustment of flow direction to prevent refrigerant from flowing back from the discharge side of the compressor to the oil sump tank during normal operation, and to return lubricating oil from the oil sump tank to the compressor through the connecting pipe when the compressor is stopped. It is configured as a refrigerator-freezer in which means are provided.

[0005]

[Operation] In the refrigerator-freezer according to the present invention, a connecting pipe line is provided that connects the discharge side of the compressor of the refrigeration cycle and the oil sump tank on the suction side thereof. Further, a flow direction adjusting means is provided in the connecting pipe. Therefore, when the compressor is stopped, the lubricating oil that has flowed back from the high-pressure compressor into the refrigerant pipe on the suction side is stored in the oil sump tank. The flow direction adjusting means returns the lubricating oil in the oil sump tank to the compressor through the connecting pipe when the compressor is stopped. This ensures an appropriate amount of lubricating oil within the compressor. Furthermore, the amount of lubricating oil sucked into the compressor does not increase when the compressor is restarted.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples embodying the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. It should be noted that the following examples are examples of embodying the present invention, and are not intended to limit the technical scope of the present invention. Here, FIG. 1 is a block diagram showing a schematic configuration of a refrigerator-freezer according to an embodiment of the present invention, viewed from the side, FIG. 2 is a block diagram showing a refrigeration cycle included in the refrigerator-freezer, and FIG. 3 is a diagram showing a refrigeration cycle equipped with the refrigerator-freezer. FIG. 4 is a graph diagram showing a sound pressure level curve after the compressor is started, and FIG. 5 is a configuration diagram showing a refrigeration cycle according to a modification of the present invention. . However, the same reference numerals are used for elements common to those of the refrigeration cycle 2b of the conventional refrigerator-freezer shown in FIG. 6, and detailed explanation thereof will be omitted. The refrigeration cycle 2 of the refrigerator-freezer according to this embodiment is as shown in FIG.
The basic structure is almost the same as the conventional refrigeration cycle 2b described above, and the difference in structure from the conventional refrigeration cycle 2b is that the oil level of the refrigerating machine oil 9 in the oil sump tank 5 is
The height positional relationship between the oil sump tank 5 and the compressor 3 is set so that the oil level is higher than the oil level in the oil sump tank 5, and the bottom of the oil sump tank 5 and the discharge pipe 10 of the compressor 3 are connected. The connecting pipe line 6 is provided, and the connecting pipe line 6 is provided with a capillary tube 7 which provides an extremely large resistance to the high-pressure refrigerant gas in the discharge pipe 10 when the compressor 3 is operated. The refrigeration cycle 2 described above is applied to the refrigerator-freezer 1 shown in FIG. The main body case 15 of the refrigerator-freezer 1 has an interior divided into a freezer compartment 16, a refrigerator compartment 17, and a vegetable compartment 18, respectively. The compressor 3 and condenser 12 of the refrigeration cycle 2 are disposed at the lower part of the main body case 15, the evaporator 14 is disposed at the back inside the freezer compartment 16, and the compressor 3, etc., and the evaporator 14, etc. and are connected by a refrigerant pipe 11. As shown in FIG. 3, the compressor 3 is provided with a motor 26 in a sealed casing 20, and a drive shaft 25 installed on the drive side of the motor 26 is connected to the front of the machine room 24. It is rotatably supported by mechanical seal portions 30 and 31 of the head 21 and rear head 22, respectively. The machine room 24 is hermetically constructed from the front head 21, rear head 22, and cylinder 23, and has a rolling piston (not shown) provided therein for compressing refrigerant gas and is fixed to the drive shaft 25. . The suction pipe 4 is connected to the upper part of the front head 21, and the machine room 2 is connected to the upper part of the front head 21.
It communicates with 4. Further, a discharge port 28 is provided at the lower part of the front head 21 to communicate the inside of the casing 20 and the machine room 24.
high pressure refrigerant gas from the machine room 24 to the casing 20
A discharge valve 27 is provided to allow the flow to flow only into the interior. A discharge pipe 10 is connected to the lower part of the casing 20 and communicates with the inside of the casing 20. In this case, the connection position of the discharge pipe 10 is set at a position higher than the oil level H of a predetermined amount of refrigerating machine oil 9 housed in the casing 20. Further, the front head 21 and the rear head 22 have a structure that does not hinder the compression of refrigerant gas and allows the refrigerating machine oil 9 to flow into the machine room 24.

The refrigerator-freezer 1 according to this embodiment has the above-mentioned configuration. Therefore, the operation of the refrigeration cycle 2 of the refrigerator-freezer 1 will be explained below using FIGS. 2 and 3. When the temperature inside the refrigerator-freezer 1 falls below a predetermined temperature, the compressor 3 is turned off. As a result, the high-pressure refrigerant gas in the machine room 24 of the compressor 3 is caused by the broken line arrow (
As shown in Figure 2), it flows back into the suction pipe 4 on the low pressure side. At this time, the refrigerating machine oil 9 in the compressor 3 also flows out into the suction pipe 4 along with the refrigerant gas. In this case, the refrigerating machine oil 9 that has reached the oil sump tank 5 from the suction pipe 4 is stored in the oil sump tank 5. After that, when the pressure in the refrigerant pipes 11 of the entire refrigeration cycle 2 settles down to a constant level, the refrigeration oil 9 in the oil sump tank 5 passes through the connecting pipe 6 and the capillary tube 7 due to its own weight and adjusts the position and height of the oil sump tank 5. It flows out into the discharge pipe 10 with a difference. Subsequently, the refrigerating machine oil 9 that has flowed out into the discharge pipe 10 returns into the casing 20 of the compressor 3. Therefore, the refrigerating machine oil 9 in the compressor 3 is
It does not decrease more than necessary even by repeating N/OFF. Therefore, the above mechanical seals 30, 31
The compressor 3 is properly lubricated, and the operation of the compressor 3 is not hindered. On the other hand, the amount of refrigerating machine oil 9 in the oil sump tank 5 decreases every time the compressor 3 stops, so it is never full and can always contain the refrigerating machine oil 9 from the suction pipe 4. can. Therefore, the amount of refrigerating machine oil 9 that accumulates in the suction pipe 4 is relatively small. On the other hand, when the temperature inside the refrigerator reaches a predetermined temperature or higher, the compressor 3 is restarted. At this time, since the amount of refrigerating machine oil 9 accumulated in the suction pipe 4 is relatively small as described above, a large amount of refrigerating machine oil 9 is sucked into the machine room 24 of the compressor 3 at once and compressed. Never. Therefore, when restarting, the compressor 3
The load applied to the system is small and does not generate large noise. The sound pressure level curve of the sound generated at this time is shown in FIG. According to this, the peak level P1 (relative value) of the sound pressure level L is 36
43 (71.2 dB: dB = 20 log L), and compared to the peak level P2 of the sound generated by the conventional device shown in Fig. 7, the noise energy is reduced to about 1/3, and the sound intensity is reduced. As a result, we were able to achieve a reduction of approximately 8 dB. The refrigerant gas sucked into the machine room 24 from the suction pipe 4 by restarting the compressor 3 is compressed in the machine room and discharged as high-pressure gas from the discharge pipe 10.
The refrigeration cycle 2 is circulated as shown by the solid arrow. At this time, a pressure difference is generated between the discharge pipe 10 and the oil sump tank 5, but the capillary tube 7 has extremely high resistance to the refrigerant gas, and most of the refrigerant gas in the discharge tube 10 flows back through the capillary tube 7. There's nothing to do. That is, the configuration in which the oil sump tank 5 is provided at a higher position than the compressor 3 and the capillary tube 7 prevent the refrigerant gas from flowing back from the discharge side of the compressor 3 to the oil sump tank 5 during normal operation.
This is a flow direction adjusting means for returning the refrigerating machine oil 9 in the oil sump tank 5 to the compressor 3 through the connecting pipe 6 when the compressor 3 is stopped.

Furthermore, it is also possible to use a solenoid valve as the flow direction adjusting means. Such an example is shown in FIG. In the refrigeration cycle 2a shown in the figure, the refrigeration cycle 2
A solenoid valve 8 is provided in the connecting conduit 6 in place of the capillary tube 7 . This electromagnetic valve 8 is configured to close the connecting pipe 6 when the compressor 3 is driven and to open the connecting pipe 6 when the compressor 3 is stopped. Therefore, when the compressor 3 is stopped, the refrigerating machine oil 9 in the oil sump tank 5 can flow through the connecting pipe 6 to the discharge pipe 10, and when the compressor 3 is running, the high-pressure refrigerant gas in the discharge pipe 10 is connected. Do not back flow through pipe 6. In addition, in the above-mentioned refrigeration cycle 2, 2a, if the height of the oil sump tank 5 is the same or lower than the height of the compressor 3, the connection pipe 6 is connected to, for example, a pump for transporting oil. It is also possible to provide a configuration in which this pump is driven when the compressor 3 is stopped and stopped when the compressor 3 is driven.

[0009]

Effects of the Invention According to the present invention, there is provided a refrigerator-freezer in which an oil reservoir tank for storing lubricating oil from the compressor is provided in the refrigerant pipe line on the suction side of a rotary compressor constituting a predetermined refrigeration cycle. , a connecting pipe is provided to connect the oil sump tank and the discharge side of the compressor, and the connecting pipe prevents backflow of refrigerant from the discharge side of the compressor to the oil sump tank during normal operation. There is also provided a refrigerator-freezer characterized in that a flow direction adjusting means is provided for returning the lubricating oil in the oil sump tank to the compressor through the connecting pipe when the compressor is stopped. Thereby, it is possible to reduce noise when the compressor is restarted. Furthermore, there is no problem in the operation of the compressor due to a decrease in the amount of oil in the compressor.

[Brief explanation of the drawing]

FIG. 1 is a side view of a schematic configuration of a refrigerator-freezer according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a refrigeration cycle included in the refrigerator-freezer.

FIG. 3 is a side sectional view showing a rotary compressor included in the refrigeration cycle.

FIG. 4 is a graph diagram showing a sound pressure level curve after the compressor is started.

FIG. 5 is a configuration diagram showing a refrigeration cycle according to a modification of the present invention.

FIG. 6 is a configuration diagram showing a refrigeration cycle of a conventional refrigerator-freezer, which is an example of the background of the present invention.

7 is a graph diagram showing a sound pressure level curve due to the compressor of the refrigeration cycle of FIG. 6. FIG.

[Explanation of symbols]

1...Freezer refrigerator 2, 2a, 2b...refrigeration cycle 3...Compressor 4...Suction pipe 5...Oil sump tank 6…Connecting pipe line 7...Capillary tube 8...Solenoid valve 9...Refrigerating machine oil 10...Discharge pipe 11... Refrigerant pipe 12...Condenser 13...Capillary tube 14...Evaporator

Claims (1)

[Claims] Claim 1: A refrigerator-freezer comprising an oil sump tank for storing lubricating oil from the compressor in a refrigerant pipe on the suction side of a rotary compressor constituting a predetermined refrigeration cycle, wherein the oil sump tank and the discharge side of the compressor, and the connecting pipe is designed to prevent the refrigerant from flowing back from the discharge side of the compressor to the oil sump tank during normal operation. A refrigerator-freezer characterized in that a flow direction adjusting means is provided for returning the lubricating oil in the oil sump tank to the compressor through the connecting pipe when the refrigerator is stopped.