JPH06323636A - Refrigerator - Google Patents

Abstract

PURPOSE:To prevent an operation under a lack of gas in a refrigerating cycle, to effect an efficient operation, a rapid returning of lube oil to a compressor 1 at the start of operation and prevent a seizure from occurring. CONSTITUTION:An accumulator 7 is arranged in such a manner that its bottom part is located at a higher position that of a liquid receiver 5. A communication pipe 10 for allowing liquid refrigerant flow in the accumulator 7 to the liquid receiver 5 is installed between these devices. Then, the communication pipe 10 is provided with a solenoid valve 11 which is opened in operation stop and closed when an operation is carried out. In addition, an oil returning pipe 14 is connected to a bottom part of the accumulator 7, and the oil returning pipe 14 is connected to a gas refrigerant outlet pipe 81 of the accumulator 7. During stopped state of the operation, the inner part of the accumulator 7 is made vacant and the liquid refrigerant is stored in the liquid receiver 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus, and more particularly, to a compressor, a heat source side heat exchanger and a use side heat exchanger, which are provided between the heat source side heat exchanger and the use side heat exchanger. The present invention relates to a refrigerating apparatus having a liquid container and an accumulator arranged on the suction side of the compressor.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a refrigeration system has an oil recovery unit B, a four-way switching valve C, a heat source side heat exchanger D, and a liquid receiver E on the refrigerant discharge side of a compressor A. , A heat exchanger F on the use side in which a hot / cold water extraction pipe F1 is piped, an accumulator G
Are connected by a refrigerant pipe H to form a refrigeration cycle. Further, expansion valves I, I are provided on both sides of the liquid receiver E in the refrigerant pipe H, respectively.

During the cooling operation by the above refrigeration system, the refrigerant discharged from the compressor A is circulated by the switching operation of the four-way switching valve C in the route shown by the solid arrow in FIG. During operation, the four-way switching valve C is also used.
The refrigerant discharged from the compressor A is circulated in the path indicated by the dotted arrow in FIG.

Further, conventionally, the oil mixed in the refrigerant gas discharged from the compressor A is separated and recovered by the oil recovery device B and is actively returned to the compressor A. The oil that cannot be separated by the oil recovery unit B mixes with the refrigerant and circulates in the refrigeration cycle. In order to positively return the oil to the compressor A, for example, the actual opening 6
The oil return structure described in Japanese Patent No. 4-9876 is proposed. In this oil return structure, as shown in FIG. 6, one end of an oil return pipe J having a small pipe diameter is opened at the bottom of the accumulator G, and the other end side of the oil return pipe J is connected to the bottom of the compressor A. The accumulator G connected to the suction side is connected in the middle of the gas refrigerant outlet pipe H1 of the accumulator G, and an opening / closing valve K that is opened in the freezing operation and closed when the operation is stopped is inserted in the oil return pipe J. When the liquid refrigerant is stored in G, since the oil mixed in the refrigerant is also stored together with the liquid refrigerant, the on-off valve K is opened during the freezing operation to store the liquid refrigerant and the oil stored in the accumulator G as described above. When the liquid refrigerant is gasified from the oil return pipe J to the gas refrigerant outlet pipe H1, the liquid refrigerant is sent to the gas refrigerant outlet pipe H1 from the oil return pipe J in an oil-rich mist state, and the compressor A is supplied.
I'm trying to get the oil back. Further, when the operation is stopped, the on-off valve K is closed to prevent the liquid refrigerant in the accumulator G from returning from the oil return pipe J to the compressor A as it is to prevent liquid compression at the time of startup. .

The oil return pipe J has a small diameter because the accumulator G has a large diameter when the diameter is increased.
Since the amount of the liquid refrigerant inside the compressor A that returns to the compressor A increases, liquid compression will occur. Therefore, in order to prevent liquid back to the compressor A, the diameter of the oil return pipe J is made small. -ing

Further, in FIG. 6, L is a filter interposed in the oil return pipe J together with an opening / closing valve K, and in FIG. 5, M is a superheat detector for adjusting the opening of the expansion valve I. Therefore, the detector M is provided at the refrigerant inlet and outlet sides of the heat source side heat exchanger D during the cooling and heating operations of the refrigerant pipe H.

[0007]

However, when performing the cooling operation in the above refrigeration system, the refrigerant is circulated through the route indicated by the solid arrow in the figure. When the operation is started in a state where the amount of the liquid refrigerant stored in the receiver E is insufficient and the amount of the liquid refrigerant in the receiver E is insufficient, the accumulator G can be easily stored in the accumulator G. Since the amount of refrigerant sucked into the compressor A is fixed, it takes time to send a sufficient amount of liquid refrigerant required for heat exchange from the compressor A to the use side heat exchanger F, Therefore, the amount of liquid refrigerant in the utilization side heat exchanger F at the start of operation is insufficient, heat exchange efficiency is deteriorated, and gas shortage operation is caused.

Further, when a large amount of liquid refrigerant is stored in the accumulator G at the start of the cooling operation, the oil-mixed liquid refrigerant stored in the accumulator G is separated from the oil and the liquid due to a difference in specific gravity during stoppage. Since the refrigerant is separated and the oil is accumulated in the upper portion of the liquid refrigerant, the liquid refrigerant accumulated in the lower side of the accumulator G is first returned from the oil return pipe J to the compressor A, After that, the oil accumulated in the upper portion of the liquid refrigerant is returned to the compressor A,
Therefore, it takes time to return the oil to the compressor A, and it is easy to cause a seizure accident due to lack of oil.

An object of the present invention is to reliably prevent out-of-gas operation in a refrigeration cycle and to operate efficiently.
Moreover, it is to provide a refrigerating device capable of quickly returning lubricating oil to the compressor side at the time of start-up to prevent a seizure accident or the like.

[0010]

To achieve the above object, the invention according to claim 1 comprises a compressor 1, a heat source side heat exchanger 4 and a utilization side heat exchanger 6, and the heat source side heat exchanger. Four
In the refrigerating apparatus in which the liquid receiver 5 is disposed between the heat exchanger 6 and the heat exchanger 6 on the use side, and the accumulator 7 is disposed on the suction side of the compressor 1, the accumulator 7 has a bottom portion that is the liquid receiver 5
The communication pipe 10 is disposed between the accumulator 7 and the liquid receiver 5 so that the liquid refrigerant in the accumulator 7 flows down to the liquid receiver 5, and the communication pipe 10 is connected between the accumulator 7 and the liquid receiver 5. Open in the tube 10 when the refrigeration system is stopped,
The solenoid valve 11 that is closed during operation is provided.

Further, according to the second aspect of the invention, the oil return pipe 14 is connected to the bottom portion of the accumulator 7, and the oil return pipe 14 is connected to the gas refrigerant outlet pipe 81 of the accumulator 7. .

[0012]

According to the first aspect of the present invention, when the refrigeration system is stopped, the solenoid valve 11 provided in the connecting pipe 10 is opened, and most of the liquid refrigerant stored in the accumulator 7 is at the bottom of the accumulator 7. A large amount of liquid refrigerant is stored in the liquid receiver 5 which is dropped and stored in the liquid receiver 5 disposed on the side. Therefore, at the start of operation of the refrigeration system,
A sufficient amount of refrigerant can be immediately supplied from the liquid receiver 5 to the use-side heat exchanger 6 during the cooling operation, and to the heat-source-side heat exchanger 4 during the heating operation. It can be prevented, and efficient operation in the refrigeration cycle can be performed. During operation of the refrigerating apparatus, the solenoid valve 11 of the communication pipe 10 is closed to prevent the high-pressure liquid refrigerant from flowing from the high-pressure liquid receiver 5 to the low-pressure accumulator 7, and the freezing is performed by the accumulator 7. Gas-liquid separation of the refrigerant circulating in the cycle is performed as in the conventional case.

According to the second aspect of the present invention, the oil return pipe 14 is connected to the bottom of the accumulator 7, and the oil return pipe 14 is connected to the gas refrigerant outlet pipe 81 of the accumulator 7. At the start of the operation, the inside of the accumulator 7 can be in a state in which almost no liquid refrigerant is stored. Therefore, the oil mixed in the liquid refrigerant flowing into the accumulator 7 by the start of the operation is immediately discharged from the oil return pipe 14 to the gas refrigerant. Since it can be quickly returned to the compressor 1 via the outlet pipe 81, seizure accident in the compressor 1 at the time of start-up can be reliably prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a screw heat pump type refrigerating apparatus, in which an oil recovery device 2, a four-way switching valve 3, a heat source side heat exchanger 4, a liquid receiver 5 are provided on a refrigerant discharge side of a screw compressor 1. The use side heat exchanger 6 and the accumulator 7 in which the hot / cold water take-out pipe 61 is piped are connected by a refrigerant pipe 8 to form a refrigeration cycle. Also, the refrigerant pipe 8
On both sides of the liquid receiver 5 in
9 is inserted.

During the cooling operation by the above refrigeration system, the refrigerant discharged from the compressor 1 by the switching operation of the four-way switching valve 3 is the oil recovery unit 2 as shown by the solid arrow in FIG. , Four-way switching valve 3, heat source side heat exchanger 4, liquid receiver 5, utilization side heat exchanger 6, four-way switching valve 3, accumulator 7, compressor 1 and the utilization side heat exchanger. 6
Becomes an evaporator, and the take-out pipe 61 in the heat exchange 6 on the use side.
The water inside is cooled, and the inside of the room is cooled by this cooling water. On the other hand, during the heating operation, the refrigerant discharged from the compressor 1 by the switching operation of the four-way switching valve 3 is used as shown by the dotted arrow in the figure, the oil recovery unit 2, the four-way switching valve 3, It is circulated to the side heat exchanger 6, the liquid receiver 5, the heat source side heat exchanger 4, the four-way switching valve 3, the accumulator 7, and the compressor 1, and the heat source side heat exchanger 4 becomes an evaporator during heating operation. , The use side heat exchanger 6 becomes a condenser, and the use side heat exchanger 6
The water in the extraction pipe 61 is heated therein, and the heated hot water heats the room. In the cooling and heating operation described above, the discharge gas refrigerant discharged from the compressor 1 collects lubricating oil when passing through the oil recovery unit 2, and the recovered lubricating oil passes through the oil supply pipe 21. And is returned to the compressor 1.

In the above refrigerating apparatus, however, as shown in FIGS. 1 and 2, the accumulator 7 is arranged such that its bottom is higher than the liquid receiver 5.
Between the bottom of the accumulator 7 and the top of the receiver 5, the liquid refrigerant in the accumulator 7 is placed in the receiver 5.
The connecting pipe 10 that flows down to the side is connected, and the connecting pipe 10 is provided with an electromagnetic valve 11 that is opened when the refrigeration system is stopped and closed when the refrigeration system is in operation.

More specifically, when the indoor unit in the refrigerating apparatus is shown in FIGS. 3 and 4, two water heat exchangers 61 and 62 as the use side heat exchanger 6 are formed in the upper and lower stages above the apparatus. The liquid receiver 5 is disposed below the water heat exchangers 61 and 62, and the liquid receiver 5 is disposed substantially parallel to the use side heat exchanger 6 and at the intermediate height position of the compressor. 1
And a drive motor 1a for the compressor 1, and the oil recovery unit 2 is provided below the compressor 1.
The accumulator 7 is installed on one side in the lateral direction of the compressor 1 and the oil recovery device 2 via a pedestal 71 so that the bottom of the accumulator 7 is higher than the receiver 5. The solenoid valve 1 is provided between the upper side and the bottom of the accumulator 7.
The connecting pipe 10 having the number 1 is provided.

The liquid refrigerant stored in the accumulator 7 when the receiver 5 and the accumulator 7 are in a pressure equalizing state by opening the solenoid valve 11 when the refrigeration system is not in operation. Most of the liquid is dropped from the connecting pipe 10 to the liquid receiver 5 disposed on the lower side of the accumulator 7 to be stored therein, and a large amount of liquid refrigerant is stored in the liquid receiver 5, and the accumulator 7 is stored. The inside of is almost empty. By doing so, since a large amount of liquid refrigerant is stored in the liquid receiver 5, when the operation of the refrigerating apparatus is started,
A sufficient amount of the refrigerant is immediately supplied to the utilization side heat exchanger 6 during the cooling operation, and to the heat source side heat exchanger 4 during the heating operation, so that the out-of-gas operation of the refrigeration system at the time of startup is prevented, The efficiency can be improved. Further, during operation of the refrigerating apparatus, the electromagnetic valve 11 is closed to cut off the communication between the accumulator 7 and the liquid receiver 5 by the communication pipe 10, so that the high pressure liquid receiver 5 lowers the pressure. The inflow of the liquid refrigerant into the accumulator 7 is blocked, and the gas-liquid separation of the refrigerant circulating in the refrigeration cycle is performed in the accumulator 7 as in the conventional case.

Further, in the above refrigeration system, as shown in FIGS. 1 to 3, an oil return pipe 14 is connected to the bottom of the accumulator 7, and the oil return pipe 14 is connected from the accumulator 7 to the compressor. Gas refrigerant outlet pipe 8 extending to 1
1, and an opening / closing valve 15 that opens and closes when stopped during freezing operation and a filter 16 may be provided in the middle of the oil return pipe 14.

With the above construction, when the operation of the refrigerating apparatus is stopped, the liquid refrigerant in the accumulator 7 falls into the receiver 5 and is stored by the opening operation of the solenoid valve 11, and the accumulator 7 is stored. Since the operation of the refrigerating apparatus can be started in a state where the liquid refrigerant is hardly stored therein, when the oil-mixed liquid refrigerant circulating in the refrigerating cycle flows into the accumulator 7 as the operation of the apparatus is started, The inflowing oil-rich liquid refrigerant is immediately transferred from the oil return pipe 14 through the gas refrigerant outlet pipe 81 to the compressor 1
Therefore, the oil can be immediately returned to the compressor 1 immediately after starting,
It is possible to reliably prevent a seizure accident in the compressor 1 at the time of startup. That is, as in the conventional case, when a large amount of liquid refrigerant is stored in the accumulator 7 at the time of starting the operation, the liquid refrigerant and the oil are separated due to the difference in specific gravity during the stop, and the liquid refrigerant and By the time the accumulated oil returns from the oil return pipe 14 to the compressor 1, it takes a long time to return the liquid refrigerant, so that it took time to return the liquid refrigerant. By starting the operation in a state where almost no liquid refrigerant is stored, the oil-rich liquid refrigerant can be quickly returned to the compressor 1 immediately after starting.

Further, in the middle of the oil return pipe 14, there are provided an on-off valve 15 which opens and closes when stopped during freezing operation, and a filter 16. In such a case, the above-mentioned valve is provided only during operation of the refrigeration system. The on-off valve 15 is opened to store the oil stored in the accumulator 7 together with the liquid refrigerant through the oil return pipe 14 and the gas refrigerant outlet pipe 81.
And when the operation is stopped, the accumulator 7
Most of the liquid refrigerant stored in the accumulator 7 drops to the receiver 5 side and is stored therein, and almost no liquid refrigerant is stored in the accumulator 7.
Since the liquid refrigerant inside the accumulator 7 and the liquid receiver 5 fall only when the pressure equalization state is reached, the on-off valve 15 is closed and the liquid refrigerant inside the accumulator 7 operates when the operation is stopped. Immediately after the stop, it is possible to surely prevent the liquid from flowing into the compressor 1 and more reliably prevent the liquid compression at the time of starting.

Further, in the conventional refrigerating apparatus shown in FIG. 5, when the heating operation is performed, the refrigerant is circulated in the path shown by the dotted arrow in the figure, and at this time, the heat source side heat exchanger serving as an evaporator. The superheat detector M provided on the refrigerant outlet side of D detects the superheat of the refrigerant passing through the refrigerant pipe H, and adjusts the opening degree of the expansion valve I based on the detection result.
The heating operation is performed by controlling the capacity of the compressor A. Particularly, in a building air conditioner or the like, the heat source side heat exchanger D is installed outdoors and the heat source side heat exchanger is installed. Since the length of the refrigerant pipe H connecting D and the expansion valve I becomes very long, when the opening degree of the expansion valve I is adjusted based on the detection result of the detector M, the expansion valve I Since an operation delay occurs and accurate superheat degree adjustment cannot be performed, the amount of refrigerant in the refrigerant pipe H outside the room increases, and a large amount of liquid refrigerant accumulates in the accumulator G. When performing the defrosting operation during the heating operation, as in the case of the cooling operation, the four-way switching valve C is switched and the compressor A Discharged refrigerant to the heat source side heat exchanger D side By Succoth, heat source side heat exchanger D
The frost that adheres to is removed, but when the above defrost operation is ended and the heating operation is started, the length of the refrigerant pipe H that connects the heat source side heat exchanger D and the liquid receiver E is Since the refrigerant pipe H is very long, a large amount of high-pressure liquid refrigerant is stored in the refrigerant pipe H, and all of this liquid refrigerant is difficult to evaporate on the heat source side heat exchanger D side. The liquid refrigerant may be sent to the accumulator G, and a large amount of the liquid refrigerant may accumulate inside the accumulator G. When a large amount of the liquid refrigerant is stored in the accumulator 7 in this manner, the gas-liquid mixed refrigerant is Since there is a problem that the compressor 1 is sucked into the compressor 1, the volume of the accumulator 7 is set to be quite large in the related art, and there is also a problem that the entire apparatus becomes very large.

Therefore, in controlling the opening / closing of the solenoid valve 11 of the connecting pipe 10, as shown in FIG. 2, a liquid level detector 12 using an ultrasonic sensor or the like is provided on the outer side of the accumulator 7, and A controller 1 for controlling the opening and closing of the solenoid valve 11 based on the detection result of the detector 12.
3, the solenoid valve 11 is closed when the liquid level in the accumulator 7 detected by the detector 12 is below a predetermined height, and the liquid level in the accumulator 7 is at a predetermined height. When the above becomes, the output from the controller 13 based on the detection result of the detector 12,
Stop the freezing operation, and after this stop, the accumulator 7
The electromagnetic valve 11 is opened after a lapse of a predetermined time in which the pressure and the liquid receiver 5 are substantially equalized, and the accumulator 7
The liquid refrigerant inside may be controlled to be stored in the liquid receiver 5.

With the above construction, when a large amount of liquid refrigerant flows into the accumulator 7 due to abnormal operation or the like, a predetermined amount or more of liquid refrigerant is stored in the accumulator 7. And the output from the controller 13 based on the detection result of the detector 12, the electromagnetic valve 11 is opened after a lapse of a predetermined time after the operation is stopped, and the liquid refrigerant in the accumulator 7 is transferred to the receiver 5
Can be stored in the accumulator 7
The liquid refrigerant can be quickly returned to the liquid receiver 5 without accumulating a large amount of the liquid refrigerant therein, and the accumulator 7 can be downsized without increasing the size of the accumulator 7 more than necessary, and the compression The liquid compressor of the machine 1 can also be prevented, and therefore the size of the entire apparatus can be reduced.

[0025]

As described above, according to the invention of claim 1, the compressor 1, the heat source side heat exchanger 4 and the use side heat exchanger 6 are provided, and the heat source side heat exchanger 4 and the heat source side heat exchanger 4 are used. In a refrigerating device in which a receiver 5 is provided between the side heat exchanger 6 and an accumulator 7 on the suction side of the compressor 1, the bottom of the accumulator 7 is located above the receiver 5. The accumulator 7 and the liquid receiver 5 are arranged as usual.
And a connecting pipe 10 for flowing down the liquid refrigerant in the accumulator 7 to the liquid receiver 5 are connected to the connecting pipe 10, and an electromagnetic valve 11 which is opened when the refrigerating device is stopped and closed when the refrigeration device is stopped is connected to the connecting pipe 10. Since it has been interposed, when the operation of the refrigeration system is stopped, the solenoid valve 11 interposed in the communication pipe 10 is opened,
Most of the liquid refrigerant stored in the accumulator 7 is
The liquid receiver 5 arranged below the accumulator 7.
A large amount of liquid refrigerant can be stored in the liquid receiver 5 by dropping to the liquid receiver 5, and therefore, from the liquid receiver 5 at the start of the operation of the refrigerating device, to the use side heat exchanger 6 at the time of cooling operation. In addition, since a sufficient amount of the refrigerant can be immediately supplied to the heat source side heat exchanger 4 during the heating operation, the gas shortage operation can be prevented and the refrigeration cycle can be efficiently operated. During operation of the refrigerating apparatus, the solenoid valve 11 of the connecting pipe 10 is closed so that the high pressure receiver 5
Since the high-pressure liquid refrigerant is prevented from flowing into the low-pressure accumulator 7 from the low pressure, the accumulator 7 can perform the gas-liquid separation of the refrigerant circulating in the refrigeration cycle as in the conventional case.

According to the second aspect of the invention, the oil return pipe 14 is connected to the bottom of the accumulator 7, and the oil return pipe 14 is connected to the gas refrigerant outlet pipe 8 of the accumulator 7.
Since it is connected to No. 1, since it is possible to make the liquid refrigerant in the accumulator 7 hardly be stored at the time of starting the operation of the refrigerating device, the oil mixed in the liquid refrigerant flowing into the accumulator 7 at the start of the operation can be removed. Immediately after passing from the oil return pipe 14 to the gas refrigerant outlet pipe 81, the compressor 1
Therefore, the seizure accident in the compressor 1 at the time of start-up can be surely prevented.

[Brief description of drawings]

FIG. 1 is a piping diagram of a refrigerating apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part thereof.

FIG. 3 is a front view showing the overall structure of the refrigeration system.

FIG. 4 is a side view of the overall structure.

FIG. 5 is a piping diagram showing a conventional general refrigeration system.

FIG. 6 is a view showing a conventional oil return structure.

[Explanation of symbols]

 1 Compressor 4 Heat Source Side Heat Exchanger 5 Liquid Receiver 6 User Side Heat Exchanger 7 Accumulator 10 Communication Pipe 11 Solenoid Valve 14 Oil Return Pipe 81 Gas Refrigerant Outlet Pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area F25B 43/02 H

Claims (2)

[Claims] 1. A compressor (1), a heat source side heat exchanger (4) and a utilization side heat exchanger (6), wherein the heat source side heat exchanger (4) and the utilization side heat exchanger (6). Liquid receiver between and (5)
In a refrigeration system in which an accumulator (7) is arranged on the suction side of the compressor (1), the accumulator (7) is arranged such that the bottom is located above the liquid receiver (5). A connection pipe (10) for connecting the liquid refrigerant in the accumulator (7) to the liquid receiver (5) is connected between the accumulator (7) and the liquid receiver (5). The communication pipe (10) is provided with a solenoid valve (11) that opens when the refrigeration system is stopped and closes when the refrigeration system is in operation. 2. The oil return pipe (14) is connected to the bottom of the accumulator (7), and the oil return pipe (14) is connected to the gas refrigerant outlet pipe (81) of the accumulator (7). The refrigerating apparatus according to 1.