JPH0875274A - Refrigerating equipment - Google Patents

Abstract

PURPOSE: To surely prevent the damage of a compressor caused by the liquid compression with a simple constitution by intermittently running the compressor when the liquid refrigerant of the prescribed volume is stored in an accumulator to circulate the refrigerant in a refrigerant circuit. CONSTITUTION: An outdoor unit 3 is provided with a compressor 15 to form a refrigerant circuit, an accumulator 17, a four-way valve 19, and an expansion valve 20. The compressor 15 is controlled by a control device 27. This control device 27 is connected to a detecting mechanism installed on the accumulator 17, and controls the operation of the compressor so as to achieve the intermittent running of the compressor when the volume of the liquid refrigerant in the accumulator 17 reaches the prescribed value. The intermittent running where the compressor is operated for (A) seconds, and then, stopped for (B) seconds is repeated by a plurality of times, preferably 5-10 times. The running time (A) is preferably 3-7 seconds, while the stopping time (B) is longer than the running time (A), preferably 5-9 seconds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus in which a refrigerant is circulated in a refrigerant circuit via an accumulator and a compressor.

[0002]

2. Description of the Related Art Generally, a refrigerant circuit of an air conditioner, which is one of refrigeration systems, is composed of an accumulator, a compressor, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger. Among them, the accumulator is The refrigerant is gas-liquid separated to prevent the liquid refrigerant from being taken into the compressor. This is to prevent damage to the compressor due to liquid compression.

However, a large amount of liquid refrigerant may accumulate in the accumulator. Even in such a case, various proposals have heretofore been made to prevent the liquid refrigerant from being supplied to the compressor.

For example, in the technique disclosed in Japanese Utility Model Publication No. 58-43735, a bypass circuit is provided to guide the liquid refrigerant overflowed by the accumulator to the discharge side of the compressor.
The liquid refrigerant is prevented from being taken into the compressor.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 62-158955, when the amount of liquid refrigerant in the accumulator exceeds a predetermined amount, the opening of the expansion valve of the refrigerant circuit is adjusted to control the circulating liquid amount. There is.

[0006]

However, in the former refrigerant circuit, the number of parts is increased because a special bypass circuit is required to prevent the compressor from taking in the liquid refrigerant. In addition, there is a problem that the configuration becomes complicated.

In the latter case, there is a problem that if the opening of the expansion valve is changed depending on the state of the accumulator, the capacity of the refrigeration system is directly affected.

Particularly, in a separation type air conditioner in which an indoor unit having an indoor heat exchanger and an outdoor unit having an outdoor heat exchanger are separated from each other, long pipes are required due to the distance between the indoor unit and the outdoor unit. In such a case, since the amount of the refrigerant circulated is large, the liquid refrigerant is likely to be accumulated in the accumulator, but a technique for surely preventing the liquid compression of the compressor without increasing the capacity of the accumulator is desired.

Therefore, an object of the present invention is to provide a refrigerating apparatus which can reliably prevent damage to the compressor due to liquid compression with a simple structure.

[0010]

In order to achieve the above object, a first invention is a refrigerating apparatus in which a refrigerant is circulated in a refrigerant circuit through an accumulator and a compressor, and a liquid refrigerant in the accumulator is The compressor is operated intermittently when a predetermined amount or more of liquid is accumulated.

A second aspect of the present invention is a refrigerating apparatus in which a refrigerant is circulated in a refrigerant circuit through an accumulator and a compressor, and when the amount of the liquid refrigerant in the accumulator is equal to or more than a predetermined amount, the operation capacity of the compressor is increased. Is operated at a low driving capacity lower than the normal driving capacity.

A third aspect of the present invention is a refrigerating apparatus in which a refrigerant is circulated in a refrigerant circuit via an accumulator and a compressor, and when a predetermined amount of liquid refrigerant in the accumulator is accumulated, the refrigerant flows into the accumulator. It has a control mechanism for controlling the quantity.

[0013]

In the refrigerating apparatus of the first invention, the compressor is operated intermittently when the amount of the liquid refrigerant accumulated in the accumulator is equal to or more than a predetermined amount. However, the intermittent operation causes the compressor to actually operate. The coil temperature rises, the lubricity of the oil in the compressor increases, and the refrigerant is gasified, so that liquid compression is prevented.

On the other hand, due to the intermittent operation, a large amount of the liquid refrigerant is not taken into the compressor but only a small amount is taken into the compressor gradually, so that the liquid refrigerant in the accumulator can be gradually reduced while preventing the liquid compression. be able to.

Therefore, damage to the compressor due to liquid compression can be reliably prevented with a simple structure without increasing the capacity of the accumulator or complicating the refrigerant circuit.

In the refrigerating apparatus of the second invention, when the liquid refrigerant is accumulated in the accumulator in a predetermined amount or more, the compressor is operated with a reduced capacity. Therefore, like the first invention, the coil in the compressor is operated. The temperature rises, the lubricity of the oil in the compressor increases, and the refrigerant is gasified, so that liquid compression is prevented.

Furthermore, since the liquid refrigerant in the accumulator is gradually taken into the compressor and discharged, liquid compression does not occur and the liquid refrigerant in the accumulator is gradually decreased.

In the refrigerating apparatus of the third aspect of the invention, when the amount of the liquid refrigerant accumulated in the accumulator exceeds a predetermined amount, the amount of the refrigerant flowing into the accumulator is reduced to prevent the liquid refrigerant from overflowing. Prevent it from being taken into the compressor.

Therefore, damage to the compressor due to liquid compression can be reliably prevented with a simple structure without increasing the capacity of the accumulator or complicating the refrigerant circuit.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, the first embodiment will be described.

FIG. 1 shows a refrigerant circuit of a separation type air conditioner (refrigerating apparatus) 1 according to the first embodiment. The air conditioner 1 comprises an outdoor unit 3 and an indoor unit 5. Has been done. A blower 6 and an indoor heat exchanger 7 are arranged in the indoor unit 5 so as to blow the air that has been heat-exchanged by the refrigerant into the room.

The outdoor unit 3 includes an outdoor heat exchanger 11
And a fan 13 for blowing air to the outdoor heat exchanger 11 are arranged to exchange heat with the outdoor unit 3. Further, the outdoor unit 3 is provided with a compressor 15, an accumulator 17, a four-way valve 19, and an expansion control valve 20 that form a refrigerant circuit.

The indoor unit 5 and the outdoor unit 3 are connected by connecting a connecting pipe 24 to the on-off valves 21 and 22, respectively. A nipple 26 provided at the end of the refrigerant pipe of the indoor unit 5 is connected to the on-off valves 21 and 22.

The connecting pipe 24 connecting the indoor unit 5 and the outdoor unit 3 is located, for example, on the first floor and the third floor or from the corner to the corner of the same floor because the indoor unit 5 and the outdoor unit 3 are located apart from each other. Therefore, it has a long distance and is configured as a so-called long pipe. As described above, when the pipe becomes a long pipe, the amount of the refrigerant circulating in the refrigerant circuit is also increased, and thus the accumulator 17 is required to have a large capacity. However, in the present embodiment, even the long pipe is used. The device is downsized and simplified without increasing the capacity of the accumulator 17.

The drive of the compressor 15 is controlled by the controller 27. The control device 27 is connected to a detection mechanism 29 (described later) provided in the accumulator 17, and when the amount of liquid refrigerant in the accumulator 17 becomes a predetermined amount or more, intermittent operation of the compressor is performed. Control the operation of.

Here, the intermittent operation of the compressor will be described.

The intermittent operation of the compressor is to repeat the inching operation, in which the compressor is operated for a predetermined time A for a few seconds and then stopped for a next predetermined time B for a few seconds. The operation time A and the stop time B are repeated.

The operating time A seconds is preferably 3 to 7 seconds, and the stop time B seconds is preferably more than A seconds and 5 to 9 seconds.

The intermittent operation is performed for several seconds A and then for several seconds B.
Operation to stop the operation for a plurality of times, preferably 5 to 1
Repeat 0 times.

The time for such intermittent operation is appropriately determined according to the conditions such as the capacity of the compressor and the capacity of the accumulator.

As shown in FIG. 2, the accumulator 17 has a refrigerant inlet 31 formed in the upper part of the case 30, from which the refrigerant is introduced through a screen 33.
The gas refrigerant is led out to the compressor 15 from the lead-out pipe 35.

The accumulator 17 has a case 30.
A detection mechanism 29 for detecting the level of the liquid refrigerant accumulated below is provided, and a detection signal of this detection mechanism 29 is sent to the above-mentioned control device 27. As shown in FIG. 2, the detection mechanism 29 is composed of a first detector 37a that detects the liquid level at the lower end and a second detector 37b that detects the liquid level at the upper end. When 37b detects the liquid level and sends a detection signal to the control device 27, the control device 27 performs the intermittent operation of the compressor 15.

Next, the operation of this embodiment will be described.

In the cooling operation, as shown by the solid arrow in FIG. 1, the refrigerant flows from the compressor 15 to the four-way valve 19, the outdoor heat exchanger 11, the expansion valve 20, the indoor heat exchanger 7 of the indoor unit 5. , And then returned to the compressor 15 via the four-way valve 19 and the accumulator 17.

On the other hand, in the heating operation, the refrigerant is the compressor 15, the four-way valve 19, the indoor heat exchanger 7 in the indoor unit 5, the expansion valve 20, the outdoor unit 3 as shown by the broken line arrow.
The heat exchanger 11, the four-way valve 19 and the accumulator 17 are returned to the compressor 15. In the accumulator 17, the refrigerant introduced from the refrigerant inlet 31 is separated into gas and liquid, and only the gas refrigerant (gas refrigerant) is led out to the compressor 15 via the lead-out pipe 35 so that liquid compression occurs in the compressor 15. To prevent.

By the way, in the case of a long pipe having a long connecting pipe 24 and a large amount of refrigerant, the required amount of refrigerant is large and the liquid level of the accumulator easily reaches the overflow level, but the amount of refrigerant liquid is the second detector. When reaching 37b, the second detector 37b transmits a detection signal to the control device 27, and the control device 27 receives the detection signal and causes the compressor 15 to operate intermittently.

That is, as shown in FIG. 3, the control device 27 determines in step S1 whether or not the liquid level switch of the second detector 37b in the accumulator 17 is turned on. When the liquid level switch is turned on, the compressor 15 is intermittently operated in step S2. On the other hand, the second detector 3
If the liquid level switch 7b is not turned on, normal operation is performed in step S3.

By carrying out such an intermittent motion, the coil in the compressor 15 is excited and its temperature rises, the lubricity of the oil in the compressor 15 increases, and the coil temperature rises, causing the refrigerant to cool. Since it is gasified, the amount of liquid in the accumulator 17 is reduced, and liquid compression due to refrigerant overflow is prevented.

Further, due to the intermittent driving of the compressor 15, the liquid refrigerant in the accumulator 17 is not taken in a large amount, and is taken into the compressor 15 little by little so as not to cause liquid compression. The liquid refrigerant in the accumulator can be gradually decreased without damaging the machine 15.

As a result of the intermittent operation, the amount of liquid in the accumulator 17 decreases, so the second detector 37b no longer detects the liquid level, and the compressor 15 is put into normal operation.

Next, the second and third embodiments of the present invention will be described.

In the second embodiment, the control method performed by the control device 27 of the first embodiment is different, and in the present embodiment, when the liquid refrigerant in the accumulator becomes a predetermined liquid amount or more, the compression is performed. Operate the machine at a lower operating capacity than the normal operating capacity. With low operating capacity, it is preferable to operate at 10% to 50% of the normal operating capacity. For example, if the normal operating frequency is 60 Hz, the operation is performed at 20 Hz. By operating the compressor 15 with a low operating capacity in this manner, the compressor 15 is operating although its capacity is low.
Similarly to the first embodiment, the temperature of the coil in the compressor 15 rises, the lubricity of the oil in the compressor increases, and the refrigerant is gasified, so that liquid compression can be prevented.

Further, since the liquid refrigerant in the accumulator 17 is taken into the compressor 15 little by little, the compressor is not damaged by the liquid compression, and the liquid refrigerant in the accumulator can be gradually reduced.

Therefore, also in the second embodiment, similarly to the first embodiment, damage to the compressor due to liquid compression can be reliably prevented with a simple structure without complicating the refrigerant circuit.

In the third embodiment, as shown in FIG. 5, an opening / closing valve 43 is provided between the accumulator 17 and the four-way valve 19, and a throttle 44 for narrowing the refrigerant flow rate in parallel with the opening / closing valve 43.
Is provided. Upon receiving the liquid level detection signal from the accumulator 17, the control device 27 closes the on-off valve 43 to flow the refrigerant to the throttle 44 and throttle the flow rate of the refrigerant flowing into the accumulator 17.

That is, in the third embodiment, when the liquid refrigerant is accumulated in the accumulator 17 by a predetermined amount or more, the amount of the refrigerant flowing into the accumulator 17 is controlled to prevent the increase of the liquid refrigerant in the accumulator 17. This prevents the liquid refrigerant from overflowing from the accumulator 17 and being taken into the compressor as it is.

In the third embodiment, the control device 27 does not control the operation of the compressor 15 but simply receives the liquid level detection signal from the accumulator 17 and opens / closes the valve 43.
With a simple structure of opening and closing, the liquid compression of the compressor is prevented.

As a method for controlling the flow rate of the refrigerant to the accumulator 17, as shown in FIG. 6, the float 39 in the accumulator 17 engages with the refrigerant inlet 31 to control the opening area of the refrigerant inlet. 41 may be provided. In this case, since the amount of the refrigerant flowing from the refrigerant inlet 31 is reduced as the liquid level of the refrigerant is increased, the control device 27 and the detection mechanism 29 are not required. Therefore, the compressor using the liquid compressor has a simpler configuration. It is possible to reliably prevent damage to the.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the scope of the present invention.

For example, as for the level detection of the liquid refrigerant in the accumulator 17, even if the predetermined liquid level is detected by the float 37 as shown in FIG. 4, the same effect can be obtained.

[0051]

According to the refrigerating apparatus of the first invention, the compressor is operated intermittently when the amount of the liquid refrigerant accumulated in the accumulator exceeds a predetermined amount. As a result, the lubricity of the oil increases and the refrigerant is gasified to prevent liquid compression.

Further, since the liquid refrigerant is taken into the compressor little by little by performing the intermittent operation of the compressor, the liquid level of the refrigerant in the accumulator can be lowered without causing liquid compression.

Therefore, according to the first aspect of the present invention, it is possible to reliably prevent damage to the compressor due to liquid compression with a simple structure without increasing the capacity of the accumulator and without complicating the refrigerant circuit.

In the refrigerating apparatus of the second invention, when the liquid refrigerant is accumulated in the accumulator by a predetermined amount or more, the compressor is operated with a reduced capacity. Therefore, as in the first invention, The coil temperature rises, the lubricity of the oil in the compressor increases, and the refrigerant is gasified, so that liquid compression can be prevented.

Furthermore, since the liquid refrigerant in the accumulator is taken into the compressor little by little, the compressor is not damaged by the liquid compression, and the refrigerant liquid level in the accumulator can be lowered.

Therefore, according to the second aspect of the present invention, it is possible to reliably prevent damage to the compressor due to liquid compression with a simple structure without increasing the capacity of the accumulator and without complicating the refrigerant circuit.

In the refrigerating apparatus of the third invention, when the amount of the liquid refrigerant accumulated in the accumulator is equal to or more than a predetermined amount, the amount of the refrigerant flowing into the accumulator is controlled, so that the increase of the liquid refrigerant in the accumulator is prevented. Therefore, the liquid refrigerant does not overflow from the accumulator and is taken into the compressor as it is.

Therefore, according to the third aspect of the present invention, it is possible to reliably prevent damage to the compressor due to liquid compression with a simple structure without increasing the capacity of the accumulator and without complicating the refrigerant circuit.

[Brief description of drawings]

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

FIG. 2 is a sectional view of the accumulator shown in FIG.

3 is a flowchart showing a control flow of the control device shown in FIG.

FIG. 4 is a cross-sectional view showing a modified example of the accumulator.

FIG. 5 is a refrigerant circuit diagram of an air conditioner according to another embodiment of the present invention.

FIG. 6 is a sectional view of an accumulator according to another embodiment.

[Explanation of symbols]

 1 Air conditioner 15 Compressor 17 Accumulator 27, 45 Control device 29 Detection mechanism 43 Opening / closing valve 44 Throttle

Claims (3)

[Claims] 1. A refrigeration system in which a refrigerant is circulated in a refrigerant circuit via an accumulator and a compressor, wherein the compressor is intermittently operated when a predetermined amount of liquid refrigerant in the accumulator is accumulated. Refrigeration equipment to be. 2. A refrigeration system in which a refrigerant is circulated in a refrigerant circuit via an accumulator and a compressor, and when the amount of liquid refrigerant in the accumulator is equal to or more than a predetermined amount, the operation capacity of the compressor is reduced to normal operation. A refrigeration system characterized by being operated at a low operating capacity lower than the capacity. 3. A refrigeration system in which a refrigerant is circulated in a refrigerant circuit via an accumulator and a compressor, and controls the amount of refrigerant flowing into the accumulator when the amount of liquid refrigerant in the accumulator exceeds a predetermined amount. A refrigerating apparatus having a control mechanism for controlling.