JP2000018739A - Heating-cooling combination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wet vapor suction to a compressor when a liquid refrigerant and a refrigerator oil are separated into two layers in an accumulator. SOLUTION: A point between a compressor 1 and a four-way valve 2 is connected to the bottom part of an accumulator 3 by a high-voltage bypass circuit 15 with a solenoid valve 13 ands restrictor device 14. Then, when separation into two layers, namely the liquid refrigerant and refrigeration machine oil in a storage room 8 is detected by a double-layer separation control detection means 17 according to a temperature that is detected by a thermistor 16, the solenoid valve 13 is opened by a valve opening/closing means 18 and a discharge gas is supplied to the storage room 8, and agitation is made by the discharge gas for forming a mixed liquid and for returning it to the compressor 1. Then, a double-layer separation control completion means 19 detects that double-layer separation is eliminated according to a temperature that the thermistor 16 detects, the valve opening/closing means 18 closes the solenoid valve 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling and heating apparatus, and more particularly to a technique for ensuring the reliability of a compressor.

[0002]

2. Description of the Related Art A conventional example of this kind of air conditioner is disclosed in Japanese Utility Model Publication No. 5-39409.

Hereinafter, referring to FIG.
The technique disclosed in Japanese Patent Publication No. 9 will be described.

In FIG. 9, which shows a refrigeration cycle of a cooling and heating apparatus, 1 is a compressor, 2 is a four-way valve, 3 is an accumulator,
4 is an outdoor heat exchanger, 5 is an outdoor expansion valve, 6 is an indoor heat exchanger, 7 is an indoor expansion valve, and these are connected via a refrigerant pipe to form a refrigeration cycle. Reference numeral 8 denotes a storage chamber of the accumulator 3, and reference numeral 9 denotes an introduction pipe, which is inserted from the upper part of the storage chamber 8 of the accumulator 3 and opens to the upper part in the storage chamber 8. Reference numeral 11 denotes a U-shaped outlet pipe attached to the suction side of the compressor 1, which is inserted from the upper part of the storage chamber 8 of the accumulator 3 and bent near the bottom of the storage chamber 8, and is bent at the upper part of the storage chamber 8. An opening 10 is formed. Reference numeral 12 denotes an oil return hole, which is opened in the pipe wall of the outlet pipe 11 located near the bottom of the storage chamber 8. Reference numeral 26 denotes an auxiliary oil return hole, which is positioned higher than the oil return hole 12 and has a plurality of openings in the pipe wall of the outlet pipe 11.

[0005] L indicates the interval at which the auxiliary oil return hole 26 is opened, and the difference C between the maximum oil amount that can be filled in the compressor 1 and the minimum oil amount required for lubrication of the compressor 1 is determined by the cross-sectional area of the accumulator 3. It is a value obtained by dividing by m (L = C / m), and this value indicates the maximum oil layer height of the oil accumulated in the accumulator 3.

[0006] H1 is the maximum refrigerant amount V and the accumulator 3
The height (H1 = V / m) divided by the cross-sectional area m of
2 is an auxiliary oil return hole 2 located at the highest position from the oil return hole 12
6, the height is set within a range (H2 <H1 + L) lower than the height obtained by adding the maximum oil layer height L to H1. The number n of the auxiliary oil return holes 26 is obtained as a value (n = H2 / L) obtained by dividing H2 by the maximum oil layer height L.

[0007] The operation of the cooling and heating apparatus configured as described above will be described. During the cooling operation, the high-temperature and high-pressure gas compressed by the compressor 1 exchanges heat with outdoor air in the outdoor heat exchanger 4 via the four-way valve 2 and condenses to become a high-pressure liquid refrigerant. Next, the pressure is reduced by the indoor expansion valve 7 through the outdoor expansion valve 5 and sent to the indoor heat exchanger 6 as a low-temperature and low-pressure two-phase refrigerant, where the heat of the indoor air is absorbed, cooled, and evaporated. The evaporated refrigerant gas passes through the four-way valve 2, is separated into gas and liquid by the accumulator 3, and is returned to the compressor 1.

During the heating operation, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 is sent to the indoor heat exchanger 6 via the four-way valve 2 and radiates heat to indoor air to be condensed. Next, the refrigerant is decompressed by the outdoor expansion valve 5 through the indoor expansion valve 7, becomes a high-temperature and low-pressure two-phase refrigerant, absorbs heat from the outdoor air in the outdoor heat exchanger 4 and evaporates, and the evaporated refrigerant gas passes through the four-way valve 2. Gas and liquid are separated by the accumulator 3 and the low-temperature and low-pressure gas returns to the compressor 1.

When no liquid refrigerant accumulates in the accumulator 3, for example, when the air conditioner performs a cooling operation when the outside air temperature is high, only the refrigerating machine oil is present at the bottom of the accumulator 3.

In this case, the oil flows from the oil return hole 12 to the outlet pipe 1.
1 and is returned to the compressor 1 together with the gas refrigerant sucked into the outlet pipe 11 from the auxiliary oil return hole 26.

Next, when the liquid refrigerant is accumulated in the accumulator 3, for example, when the air conditioner performs the cooling operation when the outside air temperature is low, the liquid refrigerant and the refrigerating machine oil are separated into two layers, The machine oil is present in the upper layer of the liquid refrigerant. This phenomenon can occur not only when using a liquid refrigerant and an incompatible refrigerating machine oil, but also when using a compatible refrigerating machine oil. For example, when a compatible polyol ester oil is used for the refrigerant R407C, which is known as an alternative refrigerant to the refrigerant R22, two-layer separation occurs. In this case, since the refrigerating machine oil exists in the upper layer, an auxiliary oil return hole is provided. It is sucked from 26 and returned to the compressor 1.

[0012]

In the conventional air conditioner, a plurality of auxiliary oil return holes 26 are provided.
When a large amount of liquid refrigerant accumulates in the accumulator 3 and the liquid level rises, the auxiliary oil return hole 26 located at a higher position
The upper layer of oil is sucked in, but at the same time, the lower layer of liquid refrigerant is sucked in from the auxiliary oil return hole 26 located below.

For this reason, as the number of the auxiliary oil return holes 26 increases, the amount of the liquid refrigerant sucked together with the refrigerating machine oil increases, so-called liquid back to the compressor 1 occurs.
Has a problem of impairing the reliability of the device.

According to the present invention, there is provided a cooling and heating apparatus which can return oil while preventing liquid back to a compressor even when a liquid refrigerant is accumulated in an accumulator in a two-layer separated state, thereby ensuring the reliability of the compressor. It is intended to provide.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the object of the present invention, the present invention provides a method for controlling the state of liquid refrigerant and refrigerating machine oil existing in a storage chamber of an accumulator.
If the temperature is detected by the thermistor and the two-layer separation is detected, the discharge gas from the compressor is directly supplied to the storage chamber through the high-pressure bypass circuit, or the refrigerant gas from the introduction pipe is low-pressure bypassed. Either eliminate the two-layer separation by directly supplying or stirring through the circuit, or open the indoor and outdoor expansion valves fully to increase the amount of liquid refrigerant in the storage chamber, and then introduce refrigerant through the inlet pipe. Either eliminate the two-layer separation by supplying gas and stirring, or freeze the upper layer while raising the liquid level by increasing the amount of liquid refrigerant in the storage chamber by fully opening the indoor and outdoor expansion valves. The plan is to release only machine oil to eliminate two-layer separation.

Then, the liquid refrigerant and the refrigerating machine oil can be returned to the compressor in a mixed state, or only the refrigerating machine oil located in the upper layer can be returned to the compressor. Can be prevented, and the reliability of the compressor can be ensured.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be embodied by the constitutions described in the respective claims. Hereinafter, embodiments of the present invention will be described together with operational effects.

According to the present invention, an accumulator for accommodating an inlet pipe and an outlet pipe having an oil return hole in a storage chamber is connected to a bottom of the accumulator from between the compressor and the four-way valve via a solenoid valve and a throttle device. A high-pressure bypass circuit, a thermistor installed on the outer wall of the accumulator,
A two-layer separation control detecting means for detecting two-layer separation based on a temperature detected by the thermistor, a valve opening / closing means for performing a two-layer separation control by opening a solenoid valve based on a command of the two-layer separation control detecting means, A two-layer separation control ending means for detecting the elimination of the two-layer separation based on the temperature detected by the thermistor and instructing the valve opening / closing means to close the solenoid valve, and a constant time elapsed from when the solenoid valve is closed. And a two-layer separation control timer for instructing the two-layer separation control detection means not to perform the two-layer separation control when the time is equal to or less than the time.

Even when the liquid refrigerant is accumulated in the storage chamber by performing the heating operation at a low outside air temperature, a certain amount of the refrigerating machine oil is returned from the oil return hole as a phase solution of the liquid refrigerant and the refrigerating machine oil. Can be. When the liquid refrigerant and the refrigerating machine oil are separated into two phases, the gas discharged from the compressor passes through the high-pressure bypass circuit and enters the inside from the bottom of the accumulator, and stirs the liquid refrigerant inside to accumulate the refrigerating machine oil and the liquid refrigerant. Is formed, and the refrigerating machine oil can be sucked through the oil return hole and returned to the compressor in the state of the mixed liquid, so that the occurrence of liquid back is eliminated.

An accumulator for accommodating an inlet pipe and an outlet pipe having an oil return hole in a storage chamber; and a low-pressure bypass circuit connected between the inlet pipe and the four-way valve to the bottom of the accumulator via an electromagnetic valve. A thermistor installed on the outer wall of the accumulator, a two-layer separation control detecting means for detecting two-layer separation based on a temperature detected by the thermistor, and an electromagnetic valve based on a command from the two-layer separation control detecting means. Valve opening / closing means for performing two-layer separation control, and detecting elimination of two-layer separation by the temperature detected by the thermistor, and instructing the valve opening / closing means to close the electromagnetic valve, and two-layer separation control ending means, When the elapsed time from when the solenoid valve is closed is a fixed time or less, a two-layer separation control timer that instructs the two-layer separation control detection unit not to perform the two-layer separation control. It includes those were.

Even if the liquid refrigerant is accumulated in the storage chamber by performing the heating operation at a low outside air temperature, a certain amount of the refrigerating machine oil is returned from the oil return hole as a phase solution of the liquid refrigerant and the refrigerating machine oil. Can be. When the liquid refrigerant and the refrigerating machine oil are separated into two layers, the refrigerant gas from the introduction pipe enters the inside of the accumulator through the low-pressure bypass circuit, agitates the liquid refrigerant inside, and refrigerating machine oil and the liquid refrigerant. Is formed, and the refrigerating machine oil can be sucked through the oil return hole and returned to the compressor in the state of the mixed liquid, so that the occurrence of liquid back is eliminated.

An accumulator for accommodating an inlet pipe and an outlet pipe having an oil return hole in a storage chamber, and an open end branched from the inlet pipe and having an open end positioned at a liquid level of a maximum refrigerant quantity of the liquid refrigerant accumulated during a normal heating operation. The stirring tube, the thermistor installed on the outer wall surface of the accumulator, the two-layer separation control detecting means for detecting the two-layer separation by the temperature detected by the thermistor, and based on the instructions of the two-layer separation control detecting means The two-layer separation control means for performing the two-layer separation control by fully opening the outdoor expansion valve and the indoor expansion valve, and detecting the elimination of the two-layer separation by the temperature detected by the thermistor, and instructing the two-layer separation control means. A two-layer separation control ending means for returning the outdoor expansion valve and the indoor expansion valve to a normal operation state, and when the elapsed time from when the two-layer separation is eliminated is a predetermined time or less, the two-layer separation control It is obtained by a two-layer separation control timer to command not to perform two-layer separation control in the release control detecting means.

Even when the liquid refrigerant is accumulated in the storage chamber by performing the heating operation at a low outside air temperature, a certain amount of the refrigerating machine oil is returned from the oil return hole as a phase solution of the liquid refrigerant and the refrigerating machine oil. Can be. When the liquid refrigerant and the refrigerating machine oil are separated into two layers, the outdoor expansion valve and the indoor expansion valve are fully opened to increase the amount of the liquid refrigerant and perform two-layer separation control to raise the liquid level in the accumulator. Then, by causing the open end of the stirring pipe to be immersed in the liquid surface, the refrigerant gas introduced from the stirring pipe stirs the liquid refrigerant inside the accumulator and the mixed liquid in which the refrigerating machine oil and the liquid refrigerant are mixed. Since the refrigerating machine oil can be sucked through the oil return hole and returned to the compressor in the state of the mixed liquid, the occurrence of liquid back is eliminated.

Further, an accumulator for accommodating an outlet pipe having an inlet pipe and an oil return hole in a storage chamber, and a pipe near the opening at the position of the maximum refrigerant quantity level of the liquid refrigerant accumulated during normal heating operation in the outlet pipe. An auxiliary hole provided in the wall, a thermistor installed on the outer wall surface of the accumulator,
Two-layer separation control detecting means for detecting two-layer separation based on the temperature detected by the thermistor, and performing two-layer separation control by fully opening the outdoor expansion valve and the indoor expansion valve based on a command from the two-layer separation control detecting means. A two-layer separation control means for detecting the elimination of the two-layer separation based on the temperature detected by the thermistor, and instructing the two-layer separation control means to return the outdoor expansion valve and the indoor expansion valve to a normal operation state; A layer separation control ending means, and a two-layer separation control timer that instructs the two-layer separation control detection means not to perform the two-layer separation control when the time from when the two-layer separation is resolved is equal to or less than a predetermined time. It is provided with.

Even if the liquid refrigerant is accumulated in the storage chamber by performing the heating operation at a low outside air temperature, a certain amount of the refrigerating machine oil is returned from the oil return hole as a phase solution of the liquid refrigerant and the refrigerating machine oil. Can be. When the liquid refrigerant and the refrigerating machine oil are separated into two layers, the outdoor expansion valve and the indoor expansion valve are fully opened to increase the amount of the liquid refrigerant, thereby performing two-layer separation control. By soaking the refrigeration oil, the refrigerating machine oil can be sucked in from the auxiliary hole and returned to the compressor, so that the occurrence of liquid back is eliminated.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling and heating apparatus according to the present invention will be described below with reference to FIGS. The same components as those described in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Embodiment 1) FIG. 1 is a refrigeration cycle diagram of a cooling and heating apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 10 denotes an opening of an outlet pipe 11 which is inserted from the upper part of the storage chamber 8 and bent near the bottom to form a U-shape, which is located at the upper part of the storage chamber 8. Reference numeral 12 denotes an oil return hole provided in the pipe wall of the outlet pipe 11, which is located near the bottom of the storage chamber 8. Reference numeral 13 denotes a solenoid valve, 14 denotes a throttle device, and 15 denotes a high-pressure bypass circuit that connects between the compressor 1 and the four-way valve 2 to the bottom of the accumulator 3, and is provided with a solenoid valve 13 and a throttle device 14. 16 is a thermistor for detecting the temperature in the storage chamber 8, 17 is a two-layer separation control detecting means for detecting two-layer separation based on the temperature detected by the thermistor 16, and 18 is a solenoid valve 13 according to a command from the two-layer separation control detecting means 17. Is a two-layer separation control ending means for detecting the elimination of the two-layer separation based on the temperature detected by the thermistor 16, and instructs the valve opening and closing means 18 to close the electromagnetic valve 13.
Reference numeral 20 denotes a two-layer separation control timer for instructing the two-layer separation control detection means 17 not to open the solenoid valve 13 until a certain period of time has elapsed after the solenoid valve 13 was closed.

Even when R407C is used as the refrigerant and a polyol ester oil compatible with the refrigerating machine oil is used, when the heating operation is performed when the outside air temperature is low, if the refrigerating machine oil and the liquid refrigerant are accumulated in the accumulator 3, The two-layer separation occurs. In this case, the density of the liquid refrigerant is about 1200 kg.
/ M ³ , and the density of the refrigerating machine oil is about 900 kg / m ³ , so that the refrigerating machine oil layer has two layers formed on the liquid refrigerant layer.

In the cooling and heating apparatus configured as described above, the heating operation is performed when the outside air temperature is low, and the operation when the liquid refrigerant and the refrigerating machine oil are separated into two layers in the accumulator 3 will be described with reference to FIGS. This will be described with reference to FIG. In addition,
Detailed description of the same operations as those described in the related art will be omitted.

FIG. 2 is a flowchart of the operation of the air conditioner in the first embodiment. In the case where the liquid refrigerant is accumulated in the storage chamber 8 when the outside air temperature is low and the liquid refrigerant is accumulated in the storage chamber 8 and is separated into two layers from the refrigerating machine oil, in STEP1, the two-layer separation control timer 20 determines whether the solenoid valve 13 was closed last time. The time up to the present time is integrated, and only when the integrated time t1 is longer than the fixed time t, the processing shifts to STEP2.

In STEP 2, when the temperature TS detected by the thermistor 16 is equal to or lower than the predetermined temperature T 1, the two-layer separation control detecting means 17 detects that the inside of the accumulator 3 is separated into two layers. Only when such detection is performed, the process proceeds to STEP3.

In STEP 3, the valve opening / closing means 18 opens the solenoid valve 13 according to a command from the two-layer separation control detecting means 17. When the solenoid valve 13 is opened, the gas discharged from the compressor 1 is introduced into the accumulator 3 through the expansion device 14 and the high-pressure bypass circuit 15 having the solenoid valve 13 to agitate the liquid refrigerant, and the refrigerating machine oil, the liquid refrigerant and Are mixed to eliminate the two-layer separation. The refrigerating machine oil is returned to the compressor 1 through the oil return hole 12 as a mixed liquid containing a certain amount of liquid refrigerant.
Move to

In STEP 4, when the temperature TS detected by the thermistor 16 becomes higher than the predetermined temperature T2, the two-layer separation control ending means 19 determines that the two-layer separation has been canceled. , STEP5
Move to

In STEP 5, the valve opening / closing means 18 closes the solenoid valve 13 in response to a command from the two-layer separation control ending means 19.

By operating as described above, the refrigerating machine oil staying in the vicinity of the liquid level can be returned to the compressor 1 through the oil return hole 12 in a state of being mixed with the liquid refrigerant. Disappears.

(Embodiment 2) FIG. 3 is a refrigeration cycle diagram of a cooling and heating apparatus according to Embodiment 2 of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals.
A detailed description thereof will be omitted.

In FIG. 3, reference numeral 21 denotes the introduction pipe 9 and the four-way valve 2.
Is connected to the bottom of the accumulator 3 and a solenoid valve 13 is provided.

In the air conditioner thus configured, the heating operation is performed when the outside air temperature is low and the liquid refrigerant in the accumulator 3 and the refrigerating machine oil are separated into two layers. This will be described with reference to FIG. In addition,
Detailed description of the same operations as those in the first embodiment will be omitted.

FIG. 4 is a flowchart of the operation of the air conditioner in the second embodiment. In the case where the liquid refrigerant is accumulated in the storage chamber 8 when the outside air temperature is low and the liquid refrigerant is accumulated in the storage chamber 8 and is separated into two layers from the refrigerating machine oil, in STEP1, the two-layer separation control timer 20 determines whether the solenoid valve 13 was closed last time. The time up to the present time is integrated, and only when the integrated time t1 is longer than the fixed time t, the processing shifts to STEP2.

In STEP 2, when the temperature TS detected by the thermistor 16 is equal to or lower than a predetermined temperature T 1, the two-layer separation control detecting means 17 detects that the inside of the accumulator 3 is separated into two layers. Only when such detection is performed, the process proceeds to STEP3.

In STEP 3, the valve opening / closing means 18 opens the solenoid valve 13 according to a command from the two-layer separation control detecting means 17. When the electromagnetic valve 13 is opened, the gas refrigerant in the introduction pipe 9 is introduced into the accumulator 3 through the low-pressure bypass circuit 21 having the electromagnetic valve 13 to stir the liquid refrigerant, and the refrigerating machine oil and the liquid refrigerant are mixed. The refrigerating machine oil is returned to the compressor 1 through the oil return hole 12 as a mixed liquid containing a certain amount of liquid refrigerant, and the process proceeds to STEP4.

In STEP 4, when the temperature TS detected by the thermistor 16 becomes higher than the predetermined temperature T2, the two-layer separation control ending means 19 determines that the two-layer separation has been avoided. , STEP5
Move to

In STEP 5, the valve opening / closing means 18 closes the solenoid valve 13 in accordance with a command from the two-layer separation control ending means 19.

By operating as described above, the refrigerating machine oil staying near the liquid level can be returned to the compressor 1 through the oil return hole 12 while being mixed with the liquid refrigerant.
No liquid back occurs.

It is necessary to design the piping so that the pressure loss of the low-pressure bypass circuit 21 is equal to or less than the pressure loss generated from the branch of the introduction pipe 9 to the accumulator 3.

(Embodiment 3) FIG. 5 is a refrigeration cycle diagram of a cooling and heating apparatus according to Embodiment 3 of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 5, reference numeral 22 denotes a liquid surface position when the liquid refrigerant accumulated in the accumulator 3 during the heating operation has the maximum refrigerant amount, and reference numeral 23 denotes a stirring pipe branched from the introduction pipe 9 inside the accumulator 3. The open end is located at the maximum refrigerant amount liquid level position 22. 24 is a two-layer separation control means.

In the cooling / heating device configured as described above, the heating operation is performed when the outside air temperature is low and the liquid refrigerant in the accumulator 3 and the refrigerating machine oil are separated into two layers. This will be described with reference to FIG. In addition,
Detailed description of the same operations as those in the first embodiment will be omitted.

FIG. 6 is a flowchart of the operation of the air conditioner in the third embodiment. In the case where the liquid refrigerant is accumulated in the storage chamber 8 and separated into two layers from the refrigerating machine oil by performing the heating operation when the outside air temperature is low, in STEP1, the two-layer separation control timer 20 determines when the previous two-layer separation is canceled. Then, the time from the current time to the present time is integrated, and only when the integrated time t1 is longer than the fixed time t, the processing shifts to STEP2.

In STEP 2, when the temperature TS detected by the thermistor 16 is equal to or lower than the predetermined temperature T1, the two-layer separation control detecting means 17 detects that the inside of the accumulator 3 is separated into two layers. Only when such detection is performed, the process proceeds to STEP3.

In STEP 3, the two-layer separation control means 24 fully opens the indoor expansion valve 7 and the outdoor expansion valve 5 in accordance with a command from the two-layer separation control detecting means 17. By fully opening the outdoor expansion valve 5 and the indoor expansion valve 7 in this way, the liquid refrigerant in the accumulator 3 accumulates to a position higher than the maximum refrigerant amount liquid level position 22 and opens to the maximum refrigerant amount liquid level position 22. The open end of the stirring pipe 23 is immersed in a liquid refrigerant. Then, the gas refrigerant introduced from the stirring pipe 23 stirs the liquid refrigerant, and the refrigerating machine oil and the liquid refrigerant are mixed. Refrigeration oil
The mixed liquid with a certain amount of liquid refrigerant is returned to the compressor 1 through the oil return hole 12, and the process proceeds to STEP4.

In STEP 4, when the temperature TS detected by the thermistor 16 becomes higher than the predetermined temperature T2, the two-layer separation control ending means 19 determines that the two-layer separation has been eliminated. When such a determination is made, the two-layer separation control means 24 is instructed by the instruction of the two-layer separation control ending means 19.
Controls the indoor expansion valve 7 and the outdoor expansion valve 5 to return to the normal heating operation.

By operating as described above, the refrigerating machine oil staying near the liquid level can be returned to the compressor 1 through the oil return hole 12 while being mixed with the liquid refrigerant. Disappears.

The pressure loss of the stirring pipe 23 is caused by the introduction pipe 9
It is necessary to design the piping so that the pressure loss generated from the branch portion to the accumulator 3 is not more than the pressure loss.

(Embodiment 4) FIG. 7 is a refrigeration cycle diagram of a cooling and heating apparatus according to Embodiment 4 of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals.
A detailed description thereof will be omitted.

In FIG. 7, reference numeral 25 denotes an auxiliary hole provided in the outlet pipe 11, which is provided at a position near the opening 10 at the maximum refrigerant amount liquid level position 22.

In the cooling / heating device configured as described above, the heating operation is performed when the outside air temperature is low, and the liquid refrigerant in the accumulator 3 and the refrigerating machine oil are separated into two layers. This will be described with reference to FIG. In addition,
Detailed description of the same operations as those in the first embodiment will be omitted.

FIG. 8 is a flowchart of the operation of the air conditioner in the fourth embodiment. In the case where the liquid refrigerant is accumulated in the storage chamber 8 when the outside air temperature is low and the liquid refrigerant accumulates in the storage chamber 8 and is separated into two layers from the refrigerating machine oil, in STEP1, the two-layer separation control timer 20 cancels the previous two-layer separation. The time from the return to the normal operation state to the present is integrated, and only when the integrated time t1 becomes longer than the fixed time t, STEP2 is performed.
Move to

In STEP 2, when the temperature TS detected by the thermistor 16 is equal to or lower than the predetermined temperature T1, the two-layer separation control detecting means 17 detects that the accumulator 3 is separated into two layers. Only when such a detection is made, the process proceeds to STEP3.

In STEP 3, the two-layer separation control means 24 fully opens the indoor expansion valve 7 and the outdoor expansion valve 5 in accordance with a command from the two-layer separation control detection means 17. In this way, by fully opening the outdoor expansion valve 5 and the indoor expansion valve 7, the liquid refrigerant in the accumulator 3 accumulates to a position higher than the maximum refrigerant amount liquid level position 22, is separated into two layers, and is positioned in the upper layer. The refrigerating machine oil rises to a position where the auxiliary hole 25 is immersed. Then, the refrigerating machine oil is returned to the compressor 1 through the auxiliary hole 25, and S
Move to TEP4.

In STEP 4, when the temperature TS detected by the thermistor 16 becomes higher than the predetermined temperature T2, the two-layer separation control ending means 19 determines that the upper-layer refrigerating machine oil separated into two layers has been returned. . When it is determined in this manner, the two-layer separation control means 24 controls the two-layer separation control means 24 to return the indoor expansion valve 7 and the outdoor expansion valve 5 to the normal heating operation in accordance with a command from the two-layer separation control ending means 19.

By operating as described above, the refrigerating machine oil staying in the vicinity of the liquid level can be returned to the compressor 1 without generating the liquid back.

[0063]

The present invention is embodied in the form described above and has the following effects.

According to the first aspect of the present invention, a high-pressure bypass circuit having an electromagnetic valve and a throttle device is provided between the compressor and the four-way valve and connected to the accumulator, and the thermistor installed in the accumulator is detected. A two-layer separation control detecting means for detecting the two-layer separation according to the temperature to be performed, and performing a two-layer separation control by opening a solenoid valve by a valve opening / closing means based on a command of the two-layer separation control detecting means, and detecting the thermistor. A two-layer separation control ending means for detecting the elimination of the two-layer separation based on the temperature to be performed, closing the solenoid valve by the valve opening / closing means based on a command of the two-layer separation control ending means, and a time during which the solenoid valve is closed Is less than a predetermined time, the two-layer separation control is controlled by the two-layer separation control timer so that the next two-layer separation control is not performed. When the two layers are separated into two layers and accumulated in the storage chamber, the two-layer separation is eliminated by being stirred by the discharge gas from the high pressure bypass circuit, and the oil can be returned while preventing the liquid back to the compressor. Thus, the reliability of the compressor can be ensured.

According to the second aspect of the present invention,
Connected to the accumulator from between the introduction pipe and the four-way valve,
A low-pressure bypass circuit having an electromagnetic valve is provided, and two-layer separation control detecting means for detecting two-layer separation is provided based on a temperature detected by a thermistor installed in the accumulator, and the valve is opened and closed based on a command from the two-layer separation control detecting means. The two-layer separation control is performed by opening the solenoid valve by the means, and the two-layer separation control ending means for detecting the elimination of the two-layer separation is provided based on the temperature detected by the thermistor. The solenoid valve is closed by the valve opening / closing means based on this.If the time during which the solenoid valve is closed is not longer than a predetermined time, control is performed by a two-layer separation control timer so as not to perform the next two-layer separation control. Even when the liquid refrigerant and the refrigerating machine oil are separated into two layers and accumulated in the storage chamber by performing the heating operation at the outside air temperature, the two layers are separated by being stirred by the gas refrigerant from the low-pressure bypass circuit. Eliminated, while preventing the liquid back to the compressor can be oil return can be secured the reliability of the compressor.

According to the third aspect of the present invention,
An inlet pipe inserted into the upper part of the storage chamber, and an oil return hole inserted through the upper part of the storage chamber, bent near the bottom of the storage chamber, opened at the upper part of the storage chamber, and located near the bottom of the storage chamber. In the accumulator having a U-shaped outlet pipe provided with a stirrer pipe which is located at the maximum refrigerant level of the liquid refrigerant which is branched from the inlet pipe and whose open end accumulates during normal heating operation, is installed in this accumulator. Two-layer separation control detecting means for detecting two-layer separation based on the temperature detected by the detected thermistor. The outdoor expansion valve and the indoor expansion valve are fully opened by the two-layer separation control means based on an instruction from the two-layer separation control detecting means. A two-layer separation control, and a two-layer separation control ending means for detecting the elimination of the two-layer separation based on the temperature detected by the thermistor. Depending on the stage, the outdoor expansion valve and the indoor expansion valve are returned to the normal operation state, and if the elapsed time from the time when the two-layer separation is resolved is shorter than a certain time, the next two-layer separation control is not performed. Since it is controlled by the layer separation control timer, by performing heating operation at a low outside air temperature, even when the liquid refrigerant and the refrigerating machine oil are separated into two layers and accumulated in the storage chamber, the outdoor expansion valve and the indoor expansion valve are fully opened. The liquid level in the storage chamber rises and is agitated by the refrigerant gas from the stirring pipe, eliminating the two-layer separation and returning the oil while preventing liquid back to the compressor, ensuring the reliability of the compressor can do.

Further, according to the invention described in claim 4, the accumulator is inserted from the introduction pipe inserted into the upper part of the storage chamber and the upper part of the storage chamber, and is bent near the bottom in the storage chamber to be bent. It has a U-shaped outlet pipe that is open at the top and has an oil return hole in the pipe wall located near the bottom of the storage chamber. The outlet pipe has a maximum refrigerant amount of the liquid refrigerant that accumulates during normal heating operation. An auxiliary hole is provided at the liquid surface position, near the opening, and two-layer separation control detecting means for detecting two-layer separation based on a temperature detected by a thermistor installed in the accumulator is provided. The two-layer separation control means performs the two-layer separation control by fully opening the outdoor expansion valve and the indoor expansion valve based on a command of the means, and detects the elimination of the two-layer separation based on the temperature detected by the thermistor. And this If the two-layer separation control means returns the outdoor expansion valve and the indoor expansion valve to the normal operation state based on the command of the layer separation control ending means, and the elapsed time from the time when the two-layer separation is eliminated is less than a certain time, Since the next two-layer separation control is controlled by the two-layer separation control timer so as not to be performed, by performing heating operation at a low outside temperature, when the liquid refrigerant and the refrigerating machine oil separate into two layers and accumulate in the storage chamber, Also,
By fully opening the outdoor expansion valve and the indoor expansion valve, the liquid level in the storage chamber rises, and the refrigerating machine oil located in the upper layer reaches the auxiliary hole, and can return oil while preventing liquid back to the compressor. Thus, the reliability of the compressor can be ensured.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of a cooling and heating device according to a first embodiment of the present invention.

FIG. 2 is a flowchart of the operation of the cooling and heating apparatus.

FIG. 3 is a refrigeration cycle diagram of a cooling and heating device according to a second embodiment of the present invention.

FIG. 4 is a flowchart of the operation of the cooling and heating apparatus.

FIG. 5 is a refrigeration cycle diagram of a cooling and heating device according to a third embodiment of the present invention.

FIG. 6 is a flowchart of the operation of the cooling and heating apparatus.

FIG. 7 is a refrigeration cycle diagram of a cooling and heating device according to a fourth embodiment of the present invention.

FIG. 8 is a flowchart of the operation of the cooling and heating apparatus.

FIG. 9 is a refrigeration cycle diagram of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Accumulator 5 Outdoor expansion valve 7 Indoor expansion valve 8 Reservoir 9 Inlet pipe 10 Opening 11 Outlet pipe 12 Oil return hole 13 Electromagnetic valve 14 Throttle device 15 High pressure bypass circuit 16 Thermistor 18 Valve opening / closing means 21 Low pressure bypass Circuit 22 Maximum refrigerant flow level 23 Stirring tube 25 Auxiliary hole

Claims (4)

[Claims] An accumulator for accommodating an outlet pipe having an inlet pipe and an oil return hole in a storage chamber; a high-pressure bypass circuit connected to the accumulator from between a compressor and a four-way valve and having an electromagnetic valve and a throttle device. A thermistor installed in the accumulator, a two-layer separation control detecting means for detecting two-layer separation based on a temperature detected by the thermistor, and a valve opening / closing means for opening the electromagnetic valve according to a command from the two-layer separation control detecting means. A two-layer separation control ending means for detecting the elimination of the two-layer separation based on the temperature detected by the thermistor and instructing the valve opening / closing means to close the electromagnetic valve, and a process since the electromagnetic valve was closed. A two-layer separation control timer for controlling the two-layer separation control detection means according to time. 2. An accumulator for accommodating an outlet pipe having an inlet pipe and an oil return hole in a storage chamber; a low-pressure bypass circuit having an electromagnetic valve connected to the accumulator from between the inlet pipe and the four-way valve; A thermistor installed in the accumulator, two-layer separation control detection means for detecting two-layer separation by the temperature detected by the thermistor, and valve opening and closing means for opening the electromagnetic valve by a command of the two-layer separation control detection means, The two-layer separation control ending means for detecting the elimination of the two-layer separation by the temperature detected by the thermistor and instructing the valve opening / closing means to close the electromagnetic valve, and by the elapsed time from when the electromagnetic valve is closed. A two-layer separation control timer for controlling the two-layer separation control detection means. 3. An accumulator for accommodating an inlet pipe and an outlet pipe having an oil return hole in a storage chamber, and an open end branched from the inlet pipe and positioned at a maximum refrigerant amount level of the liquid refrigerant accumulated during a normal heating operation. The stirring pipe, the thermistor installed in the accumulator, the two-layer separation control detecting means for detecting the two-layer separation by the temperature detected by the thermistor, the outdoor expansion valve and the outdoor expansion valve according to the instruction of the two-layer separation control detecting means A two-layer separation control unit for fully opening the indoor expansion valve, and detecting the elimination of the two-layer separation by the temperature detected by the thermistor, and instructing the two-layer separation control unit to output the outdoor expansion valve and the indoor expansion valve. A two-layer separation control ending means for returning to the normal operation state, and a two-layer separation control timer for controlling the two-layer separation control detection means by an elapsed time from when the two-layer separation is eliminated. Air conditioner equipped with. 4. An accumulator for accommodating an inlet pipe and an outlet pipe having an oil return hole in a storage chamber, and a portion of the inlet pipe near the opening at a maximum refrigerant quantity level of a liquid refrigerant accumulated during a normal heating operation. An auxiliary hole provided in the accumulator, a thermistor installed in the accumulator, a two-layer separation control detecting means for detecting two-layer separation based on a temperature detected by the thermistor, and an outdoor expansion valve according to an instruction of the two-layer separation control detecting means. And a two-layer separation control unit for fully opening the indoor expansion valve, and detecting the elimination of the two-layer separation based on the temperature detected by the thermistor, and instructing the two-layer separation control unit to output the outdoor expansion valve and the indoor expansion. A two-layer separation control ending means for returning the valve to a normal operating state; A cooling and heating device with an imager.