JPH08313077A - Air conditioner - Google Patents

Abstract

PURPOSE: To secure an amount of a lubricating oil in a compressor against changes in load, at the time of restarting or at restarting of the operation. CONSTITUTION: An outdoor unit 7 comprising a compressor 1, an outdoor heat exchanger 3, an expansion valve 5, an outdoor fan and the like and a room unit 10 comprising a room heat exchanger 8 and a room fan 9 and the like are connected by a piping and an oil separator 6 is provided on the discharge side of the compressor 1. A bottom part of the oil separator 6 is connected to the compressor 1 by a piping through a throttle mechanism 12 and a piping connected to the compressor 1 through the throttle mechanism 12 is connected above the maximum height of an oil surface in the compressor 1. With the throttle mechanism as a flow rate varying throttle mechanism, a stoppage oriented controller 13 of the compressor is provided to increase the flow rate of the flow rate varying mechanism 12 after the expansion valve 5 is closed fully during the stoppage of the compressor. Furthermore, with the throttle mechanism 12 as flow rate varying throttle mechanism, a start-oriented controller 14 of the compressor is provided to increase the flow rate of the flow rate varying throttle mechanism 12 at the starting of the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having an oil separator.

[0002]

2. Description of the Related Art Conventionally, there is an air conditioner as shown in FIG. In FIG. 2, 1 is a compressor, 2 is a four-way valve for switching between cooling operation and heating operation, 3 is an outdoor heat exchanger, 4 is an outdoor fan, 5 is an expansion valve, 6 is an oil separator, and an outdoor unit. Make up 7. 8 is an indoor heat exchanger,
An indoor fan 9 constitutes an indoor unit 10. Further, the compressor 1, the oil separator 6, the four-way valve 2, the outdoor heat exchanger 3,
The expansion valve 5, the indoor heat exchanger 8 and the like are connected by piping, and a refrigerant is sealed inside. Lubricating oil for lubricating and cooling a compressor mechanical portion (not shown) and cooling a motor (not shown) in the compressor is enclosed in the compressor 1.

When the indoor unit 10 is used for cooling, the four-way valve 2 is switched as shown by the solid line in FIG. 2 so that the outdoor heat exchanger 3 acts as a condenser and the indoor heat exchanger 8 acts as an evaporator. When heating is performed in the indoor unit 10, the four-way valve 2 is switched as shown by the broken line in FIG. 2 so that the outdoor heat exchanger 3 functions as an evaporator and the indoor heat exchanger 8 functions as a condenser.

Here, the oil separator 6 is provided on the discharge side of the compressor 1, and the bottom portion of the oil separator 6 and the bottom portion of the compressor 1 are connected by piping via a throttle mechanism 11. Therefore, the lubricating oil discharged from the compressor 1 together with the refrigerant is partly separated from the refrigerant by the oil separator 6 and returned to the bottom of the compressor 1 through the throttle mechanism 11, while the other parts pass through the four-way valve 2 together with the refrigerant. It is introduced into the heat exchanger that serves as a condenser (the outdoor heat exchanger 3 during cooling, the indoor heat exchanger 8 during heating), and further the expansion valve 5 and the heat exchanger that serves as an evaporator (indoor heat exchanger 8 during heating, heating Sometimes, it is sucked into the compressor 1 again via the outdoor heat exchanger 3) and the four-way valve 2.

[0005]

However, in the above-mentioned conventional example, the oil separator 6 cannot completely separate the refrigerant and the lubricating oil, and a part of the refrigerant together with the lubricating oil passes through the throttling mechanism 11 to the compressor. Returned to the bottom of 1. At this time, the refrigerant is blown into the lubricating oil staying at the bottom of the compressor 1, and the dissolution of the refrigerant in the lubricating oil is promoted. After that, when the pressure in the compressor 1 is reduced due to a change in the air conditioning load, the refrigerant in the lubricating oil foams,
A large amount of lubricating oil is discharged from the compressor 1 together with the refrigerant, and the lubricating oil becomes insufficient in the compressor 1, which causes a problem such as abnormal wear of the mechanical portion and seizure.

In addition, the pressure difference (difference between discharge pressure and suction pressure)
When the compressor 1 is started in a certain state, an excessive current may flow to a motor (not shown) in the compressor 1 and the motor may burn out. The valve 5 was operated in the opening direction to eliminate the pressure difference. However, when the expansion valve 5 is operated in the opening direction and the pressure difference disappears, the lubricating oil in the oil separator 6 does not return to the compressor 1, and when the compressor 1 is restarted, the lubricating oil becomes insufficient and mechanical parts There was a problem of causing abnormal wear and seizure.

Further, when the compressor 1 is started, the pressure in the compressor 1 is rapidly reduced, so that the refrigerant dissolved in the lubricating oil is foamed during the stop, and a large amount of lubricating oil is discharged from the compressor 1 together with the refrigerant. There was a problem that the lubricant was discharged and the lubricating oil became insufficient in the compressor 1 to cause problems such as abnormal wear and seizure of the mechanical portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an air conditioner which can always secure the lubricating oil in the compressor to ensure the reliability.

[0009]

In order to achieve the above object, the present invention provides an outdoor unit including a compressor, an outdoor heat exchanger, an expansion valve, an outdoor fan, and an indoor unit including an indoor heat exchanger, an indoor fan, and the like. The pipes are connected to the compressor, an oil separator is provided on the discharge side of the compressor, the bottom of the oil separator and the compressor are connected via a throttle mechanism, and the pipe connected to the compressor via the throttle mechanism is It is characterized in that it is connected above the maximum oil level in the compressor.

Further, the throttle mechanism is a variable flow throttle mechanism, and a compressor stop controller for increasing the flow rate of the variable flow throttle mechanism is provided after the indoor expansion valve is fully closed when the compressor is stopped. It is a thing.

Further, the present invention is characterized in that the throttle mechanism is a variable flow throttle mechanism, and a compressor start-up controller for increasing the flow rate of the variable flow throttle mechanism when the compressor is started is provided.

[0012]

In the air conditioner configured as described above, the bottom of the oil separator and the compressor are connected by piping through the throttle mechanism, and the piping connected to the compressor through the throttle mechanism is the maximum oil level in the compressor. By connecting to the upper part of the compressor, the refrigerant returned to the bottom of the compressor through the throttling mechanism together with the lubricating oil separated by the oil separator does not blow into the lubricating oil accumulated in the bottom of the compressor. Since the dissolution of the refrigerant in the lubricating oil is not promoted, refrigerant bubbling in the lubricating oil is suppressed when the pressure inside the compressor drops due to fluctuations in the air conditioning load, and a large amount of lubricating oil is discharged from the compressor along with the refrigerant. It is possible to avoid problems such as abnormal wear and seizure of the mechanical part due to lack of lubricating oil in the compressor when the pressure in the compressor drops due to fluctuations in the air conditioning load.

Further, by providing a compressor stop time controller for increasing the flow rate of the flow rate variable throttle mechanism after the expansion valve is fully closed when the compressor is stopped, the pressure difference is eliminated when the compressor is stopped. Since the lubricating oil in the oil separator is surely returned to the compressor, the lubricating oil is secured when the compressor is restarted, and troubles such as abnormal wear and seizure of the mechanical part can be avoided.

Further, by providing a compressor start-up controller for increasing the flow rate of the variable flow restrictor mechanism at the time of compressor start-up, it is possible to prevent a sudden pressure drop in the compressor at start-up and to dissolve it in the lubricating oil. The refrigerant is rapidly foamed to reduce the amount of lubricating oil discharged from the compressor together with the refrigerant, and the discharged lubricating oil is separated by the oil separator and returns to the compressor via the variable flow throttle mechanism. Can promote
Lubricating oil is secured in the compressor, and the compressor has stopped for a long time, and a large amount of refrigerant has melted into the lubricating oil. It can be avoided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a block diagram of an air conditioner of an embodiment according to the present invention, and the same components as those of FIG. 2 showing a conventional example are designated by the same reference numerals.

In FIG. 1, 1 is a compressor, 2 is a four-way valve for switching between cooling operation and heating operation, 3 is an outdoor heat exchanger,
4 is an outdoor fan, 5 is an expansion valve, 6 is an oil separator, and constitutes an outdoor unit 7. Further, 8 is an indoor heat exchanger, 9 is an indoor fan, and constitutes an indoor unit 10. Further, the compressor 1, the oil separator 6, the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 5, the indoor heat exchanger 8 and the like are connected by piping, and a refrigerant is sealed inside. Lubricating oil for lubricating and cooling a compressor mechanical portion (not shown) and cooling a motor (not shown) in the compressor is enclosed in the compressor 1.

The oil separator 6 is provided on the discharge side of the compressor 1, and the bottom portion of the oil separator 6 and the bottom portion of the compressor 1 are connected to each other via a variable flow restricting mechanism 12. Therefore, a part of the lubricating oil discharged from the compressor 1 together with the refrigerant is separated from the refrigerant by the oil separator 6 and returned to the bottom of the compressor 1 via the variable flow restricting mechanism 12, but the other part together with the refrigerant is the four-way valve 2 Is introduced into a heat exchanger (an outdoor heat exchanger 3 during cooling, an indoor heat exchanger 8 during heating) via which the expansion valve 5 and an evaporator (a heat exchanger 8 during cooling) are introduced. During heating, it is sucked into the compressor 1 again via the outdoor heat exchanger 3) and the four-way valve 2. The pipe connected to the compressor 1 via the variable flow rate throttle mechanism 12 is connected above the maximum oil level in the compressor.

Here, the oil separator 6 cannot completely separate the refrigerant and the lubricating oil, and a part of the refrigerant together with the lubricating oil is returned to the bottom of the compressor 1 through the variable flow restricting mechanism 12. However, through the variable flow restrictor mechanism 12, the compressor 1
Since the pipe connected to is connected above the maximum oil level in the compressor, the refrigerant that has passed through the flow rate variable throttle mechanism 12 is not blown into the lubricating oil accumulated in the bottom of the compressor, and the lubricating oil Since the dissolution of the refrigerant therein is not promoted, the refrigerant bubbling in the lubricating oil is suppressed even when the pressure inside the compressor is lowered due to the fluctuation of the air conditioning load, and a large amount of lubricating oil is discharged from the compressor 1 together with the refrigerant. Disappears. That is, even when the pressure inside the compressor is reduced due to fluctuations in the air conditioning load, it is possible to avoid problems such as abnormal wear and seizure of the mechanical part due to insufficient lubricating oil in the compressor.

Next, the operation of the compressor stop-time controller 13 that increases the flow rate of the variable flow restrictor mechanism 12 after the expansion valve 5 is fully closed when the compressor 1 is stopped will be described.

When the compressor 1 is stopped, the compressor stop controller 13 first operates the expansion valve 5 in the closing direction to fully close it. Therefore, the parts from the compressor 1 discharge part to the oil separator 6, the condenser (the outdoor heat exchanger 3 during cooling, the indoor heat exchanger 8 during heating), the expansion valve 5 are in a high pressure state, and the expansion valve 5 evaporates. A low pressure state is maintained inside the compressor (the indoor heat exchanger 8 during cooling, the outdoor heat exchanger 3 during heating), the suction portion of the compressor 1 and the inside of the compressor 1. In addition, by waiting for a certain time in this state, the lubricating oil such as the wall surface in the oil separator 6 stays at the bottom of the oil separator 6 due to gravity. That is, the refrigerant and the lubricating oil are reliably separated in the oil separator 6, and the lubricating oil exists at the bottom of the oil separator 6 and the refrigerant above it. Therefore, the controller 13 at the time of stopping the compressor is operated to increase the flow rate of the variable flow restricting mechanism 12 after waiting for a certain period of time, so that the pressure inside the oil separator 6 (high pressure) and the pressure inside the compressor 1 (low pressure). The lubricating oil separated at the bottom of the oil separator 6 due to the difference in pressure is reliably returned to the inside of the compressor 1, and the pressure difference between the discharge portion and the suction portion is also eliminated. That is, when the compressor 1 is restarted, the lubricating oil in the compressor 1 is secured to prevent abnormal wear and seizure of the mechanical section, and the restart can be performed without a pressure difference between the discharge section and the suction section, so that the motor will not burn out. It can be prevented.

Next, at the time of starting the compressor, the variable flow throttle mechanism 1
The operation of the compressor startup controller 14 for increasing the flow rate of 2 will be described.

When the compressor 1 is started up, the compressor start-up controller 14 first operates so as to increase the flow rate of the variable flow throttle mechanism 12. Then, the refrigerant and the lubricating oil discharged from the compressor 1 are introduced from the top of the oil separator 6 through the four-way valve 2 into the condenser (the outdoor heat exchanger 3 during cooling, the indoor heat exchanger 8 during heating) and It is divided into a part of the lubricating oil and a part of the refrigerant and the lubricating oil which are returned from the bottom of the oil separator 6 to the compressor 1 via the variable flow rate throttle mechanism 12. Since the compressor startup controller 14 is operating so that the flow rate of the variable flow throttle mechanism 12 increases, the amount of refrigerant and lubricating oil returned to the compressor 1 via the variable flow throttle mechanism 12 increases.
In the compressor 1, a rapid pressure drop is suppressed, the refrigerant dissolved in the lubricating oil foams violently, and the amount of the lubricating oil discharged from the compressor 1 together with the refrigerant can be reduced, and the discharged lubricating oil can be reduced. Is separated by the oil separator 6 and returned to the compressor 1 via the variable flow rate throttle mechanism 12.

Further, the refrigerant becomes high temperature and high pressure when compressed by the compressor mechanical portion, but by returning a part of the high temperature refrigerant to the inside of the compressor 1 through the variable flow restricting mechanism 12 together with the lubricating oil, It is possible to gradually raise the temperature of the lubricating oil inside the compressor 1 and expel the refrigerant dissolved in the lubricating oil little by little. Therefore, after a certain period of time from the start of the compressor 1 or when the temperature of the compressor 1 or the temperature of the lubricating oil rises, the controller 14 at the time of starting the compressor decreases the flow rate of the variable flow throttle mechanism 12 (that is, from the four-way valve 2 to the condenser). Even if the pressure inside the compressor 1 is reduced by operating the flow rate of the introduced refrigerant to increase the amount of refrigerant that contributes to heating or cooling, the rapid foaming phenomenon is suppressed and the compressor 1 discharges. The amount of lubricating oil used can be reduced. As described above, even when the compressor 1 is stopped for a long time and is started in a state where a large amount of refrigerant is dissolved in the lubricating oil, the amount of lubricating oil in the compressor can always be ensured by the compressor startup controller 14. It is possible to avoid problems such as abnormal wear and seizure of the mechanical part.

In the present embodiment, the bottom of the oil separator 6 and the compressor 1 are connected to each other via the variable flow restricting mechanism 12, but the present invention is not limited to this. It is obvious that the flow rate variable throttle mechanism 12 can be substituted by connecting the bottom of the container 6 and the compressor 1 in parallel with a plurality of capillaries and solenoid valves, which is included in the present invention.

[0026]

As is apparent from the above description, the present invention is configured such that the bottom of the oil separator and the compressor are connected by piping through the throttle mechanism, and the piping connected to the compressor through the throttle mechanism is By connecting above the maximum oil level in the compressor, the refrigerant returned to the bottom of the compressor through the throttling mechanism together with the lubricating oil separated by the oil separator is retained in the lubricating oil that has accumulated in the bottom of the compressor. Since the refrigerant is not blown in and the dissolution of the refrigerant in the lubricating oil is not promoted, the refrigerant bubbling in the lubricating oil is suppressed when the pressure inside the compressor decreases due to fluctuations in the air conditioning load, etc. Lubricating oil is not discharged from the compressor, and problems such as abnormal wear and seizure of the mechanical part due to insufficient lubricating oil in the compressor can be avoided when the pressure inside the compressor drops due to fluctuations in the air conditioning load.

Further, according to the present invention, by providing a compressor stop time controller for increasing the flow rate of the flow rate variable throttle mechanism after the expansion valve is fully closed when the compressor is stopped, the pressure difference when the compressor is stopped is provided. In order to ensure that the lubricating oil in the oil separator is returned to the compressor, the lubricating oil is secured when the compressor is restarted, and problems such as abnormal wear and seizure of the mechanical part can be avoided. .

Further, according to the present invention, by providing a compressor start-up controller for increasing the flow rate of the variable flow restricting mechanism at the time of compressor start-up, it is possible to prevent a sudden pressure drop in the compressor at start-up, and to improve the lubricating oil. The refrigerant that was dissolved inside suddenly foams to reduce the amount of lubricating oil that is discharged from the compressor together with the refrigerant, and the discharged lubricating oil is separated by an oil separator and compressed via a variable flow restrictor mechanism. It is possible to promote returning to the inside of the machine, lubricating oil is secured in the compressor, and the compressor has stopped for a long time and a large amount of refrigerant has dissolved in the lubricating oil. It is possible to avoid a problem that causes a problem such as burn-in.

The present invention can realize an air conditioner in which the reliability of the compressor is ensured in this way.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an air conditioner of an embodiment according to the present invention.

FIG. 2 is a configuration diagram of a conventional air conditioner.

[Explanation of symbols]

 1 compressor 2 four-way valve 3 outdoor heat exchanger 4 outdoor fan 5 expansion valve 6 oil separator 7 outdoor unit 8 indoor heat exchanger 9 indoor fan 10 indoor unit 11 throttle mechanism 12 flow rate variable throttle mechanism 13 compressor stop controller 14 Compressor start-up controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keito Naka, 4-2-5 Takada Hondori, Higashi-Osaka City, Osaka Prefecture Matsushita Cold Machinery Co., Ltd.

Claims (3)

[Claims] 1. An outdoor unit having at least a compressor, an outdoor heat exchanger and an expansion valve and an indoor unit having at least an indoor heat exchanger are connected by piping, and an oil separator is provided on the discharge side of the compressor. The bottom of the oil separator and the compressor are connected by piping via a throttle mechanism, and the piping connected to the compressor by the throttle mechanism is connected above the maximum oil level in the compressor. An air conditioner characterized by that. 2. A throttle stop mechanism is a variable flow throttle mechanism, and a compressor stop time controller for increasing the flow rate of the variable flow throttle mechanism is provided after the expansion valve is fully closed when the compressor is stopped. The air conditioner according to claim 1. 3. The air conditioner according to claim 1, wherein the throttle mechanism is a variable flow throttle mechanism, and a compressor startup controller for increasing the flow rate of the variable flow throttle mechanism when the compressor is started is provided. .