JP3661003B2 - Refrigeration equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a refrigeration apparatus that supplies liquid refrigerant to a compressor motor to cool the motor.
[0002]
[Prior art]
Conventionally, as disclosed in Japanese Utility Model Laid-Open No. 50-142511 and as shown in FIG. 3, a compressor P, a condenser C, an expansion mechanism V, and an evaporator E are provided, and a high-pressure liquid region on the outlet side of the condenser C A refrigerant supply passage B having a throttle valve K in the middle is connected between the compressor motor M and the compressor motor M, liquid refrigerant is supplied to the compressor motor M by differential pressure, and the motor M is cooled to overheat it. To prevent and expand the operating range. The cooling refrigerant after being supplied to the compressor motor M is discharged to an intermediate pressure region after the intake and confinement of the compressor P through a drain passage D opened in the motor casing F.
[0003]
[Problems to be solved by the invention]
However, in the above, since the cooling refrigerant supplied to the compressor motor M is discharged to the intermediate pressure range after the intake and closing of the compressor P, when the high and low differential pressure at the time of starting or the like is small, The pressure difference between the intermediate pressure region of the compressor P is smaller, or rather, the reverse pressure phenomenon occurs in which the intermediate pressure region that becomes the closed and closed chamber becomes higher than the high pressure region after the discharge passage. There arises a problem that the flow of drain from the high pressure liquid region to the intermediate pressure region of the compressor P through the compressor motor M is not ensured. For this reason, there is a problem in that the cooling of the compressor motor M cannot be ensured at the time of a low differential pressure such as at the time of starting and the reliability is lowered.
[0004]
Here, the outlet of the drain passage D is connected to the low pressure region downstream of the expansion mechanism V such as the evaporator E, and the differential pressure is maximized between the high pressure liquid region on the cooling refrigerant supply side. However, in this case, during normal operation with a predetermined high and low differential pressure, the intake air volume of the compressor P is inhibited by the amount of liquid that has cooled the compressor motor M, and the refrigerating capacity This causes a problem of lowering.
[0005]
The main purpose of the present invention is to ensure cooling of the compressor motor even at low differential pressures such as at the start, and to ensure cooling of the compressor motor while suppressing a decrease in refrigeration capacity during normal operation. It is in providing a refrigeration apparatus that can be used.
[0006]
[Means for Solving the Problems]
Therefore, in order to achieve the main object, the invention described in claim 1 includes a compressor 1, a heat source side heat exchanger 2, an expansion mechanism 3 and a use side heat exchanger 4, and includes a high pressure liquid region and a compressor motor 10. In the refrigeration apparatus connected to the refrigerant supply passage 7 for supplying the motor cooling refrigerant, the first drain passage 71 for discharging the cooling refrigerant supplied to the compressor motor 10 to the low pressure region and the intake of the compressor 1 A second drain passage 72 that discharges to the intermediate pressure region after being closed, and when the pressure difference between the suction side and the discharge side of the compressor 1 falls below a predetermined value, the first drain passage 71 passes through the first drain passage 71. drainage is discharged to the low pressure fluid area, the differential pressure is provided a passage control mechanism 90 for discharging the drain to the intermediate pressure region of the compressor 1 through the second drain passage 72 when the predetermined value or more.
[0007]
According to the second aspect of the present invention, in order to achieve the main object with a simple configuration, in the first aspect of the present invention, the first drain passage 71 and the second drain passage 70 are provided in the main drain passage 70 extending from the compressor motor 10. The drain passage 72 is branched to provide an on-off valve 91 in the middle of the first drain passage 71 and a check valve 92 in the middle of the second drain passage 72 to constitute a passage control mechanism 90. did.
[0008]
[Action]
In the first aspect of the present invention, when the pressure difference between the suction side and the discharge side of the compressor 1 at the time of starting or the like is lower than a predetermined value, the refrigerant after cooling the compressor motor 10 is the first It is discharged to the low pressure region through the drain passage 71. At the time of this low differential pressure, the discharge side is a low pressure region with respect to the high pressure liquid region on the cooling refrigerant supply side, and the differential pressure therebetween can be ensured to the maximum. Thus, the cooling refrigerant can be smoothly flowed, and cooling of the compressor motor 10 can be ensured even when the differential pressure is low. Normal differential pressure which is the pressure difference between the suction side of the compressor 1 discharge side becomes the predetermined value or more operation, refrigerant after cooling the compressor motor 10, through the second drain passage 72, the compression It is discharged to the intermediate pressure range after the intake and closing of the machine 1. Therefore, it is possible to prevent the intake air volume of the compressor 1 from being hindered, and it is possible to ensure the cooling of the compressor motor 10 with the liquid refrigerant while suppressing a decrease in the refrigerating capacity.
[0009]
According to the second aspect of the present invention, when the pressure difference at the time of starting or the like is lower than a predetermined value, the refrigerant flowing into the main drain passage 70 after cooling the compressor motor 10 by opening the on-off valve 91 is not a check valve. Instead of flowing through the second drain passage 72 with the 92 interposed therebetween, it flows into the first drain passage 71 and is discharged to the low pressure region. During normal operation in which the high / low differential pressure is greater than or equal to a predetermined value, the on / off valve 91 is closed so that the refrigerant flowing into the main drain passage 70 after cooling the compressor motor 10 passes through the check valve 92 and passes through the second drain passage 72. And discharged to the intermediate pressure region of the compressor 1. In this way, the passage control mechanism 90 can be simply configured by one on-off valve 91 and one check valve 92.
[0010]
【Example】
FIG. 1 shows a heat pump type refrigeration apparatus that can be cooled and heated. From a discharge port 11 of a compressor 1 that directly connects a compressor motor 10 that is an electric motor, a discharge pipe 51 having a discharge check valve 80, a four-way switching valve. 6 first fixed port 61, first switching port 63 of the four-way switching valve 6, gas pipe 52, air-cooled heat source side heat exchanger 2 which becomes a condenser during cooling and an evaporator during heating, liquid pipe 53, a first rectifying check valve 71 that performs a rectifying action in accordance with switching between heating and cooling, a liquid receiver 81, a dryer filter 82, a high-pressure liquid pipe 54, a main refrigerant circuit opening / closing valve 83 including an electromagnetic valve, and an electric expansion valve. The expansion mechanism 3, the low-pressure liquid pipe 55, the second rectifying check valve 72 that performs a rectifying action in accordance with switching between cooling and heating, the dry use side heat exchanger 4 that serves as an evaporator during cooling and a condenser during heating, and a gas pipe 56, the second switching port 64 of the four-way switching valve 6, and the four-way switching valve 6 Second fixed port 62, the low pressure gas pipe 57, a suction accumulator 9, those with a pipe structure that leads to the suction pipe 58, the suction port 12 of the compressor 1.
[0011]
Between the connection part of the use side heat exchanger 4 and the second rectification check valve 72 and the liquid receiver 81, a high pressure liquid pipe 59 for heating having a third rectification check valve 73 is provided. The fourth rectification check valve is provided between the connection portion between the expansion mechanism 3 and the second rectification check valve 72 and the connection portion between the heat source side heat exchanger 2 and the first rectification check valve 71. A heating low-pressure liquid pipe 60 having a valve 74 is connected thereto.
[0012]
Thus, at the time of cooling, when the refrigerant follows the code, 1, 11, 80, 51, 61, 6, 63, 52, 2, 53, 71, 81, 82, 54, 83, 3, 55, 72, 4, It circulates through the path | routes 56, 64, 6, 62, 57, 9, 58, 12, 1, and it is made to produce | generate cold water with the utilization side heat exchanger 4 used as an evaporator.
[0013]
Also, during heating, the refrigerant follows the same reference numerals as follows: 1, 11, 80, 51, 61, 6, 64, 56, 4, 73, 59, 81, 82, 54, 83, 3, 55, 60, 74 , 53, 2, 52, 63, 6, 62, 57, 9, 58, 12, 1 are circulated and hot water is generated by the use side heat exchanger 4 serving as a condenser.
[0014]
With the above configuration, the refrigerant supply passage 7 is connected between the high-pressure liquid pipe 54 and the compressor motor 10, and the cooling operation on-off valve 700 comprising an electromagnetic valve interposed in the middle thereof is opened to A refrigerant is supplied to the compressor motor 10 to cool the motor 10.
[0015]
Then, as a configuration of the drain processing passage for the cooling refrigerant supplied to the compressor motor 10, an intermediate between the first drain passage 71 for discharging the drain to the low-pressure liquid pipe 55 on the downstream side of the expansion mechanism 3 and the compressor 1. A second drain passage 72 is provided through the port 13 to discharge to the intermediate pressure range after the intake and closing. Further, when the height difference pressure is lower than a predetermined value, the drain is discharged to the low pressure liquid pipe 55 through the first drain passage 71, and when the height difference pressure is equal to or higher than the predetermined value, the intermediate pressure of the compressor 1 is passed through the second drain passage 72. A passage control mechanism 90 for discharging the drain is provided in the area.
[0016]
More specifically, the first drain passage 71 and the second drain passage 72 are branched and connected to the main drain passage 70 extending from the bottom of the casing of the compressor motor 10. The passage control mechanism 90 is configured by inserting an opening / closing valve 91 formed of an electromagnetic valve in the part and a check valve 92 in the middle of the second drain passage 72.
[0017]
The on-off valve 91 constituting the passage control mechanism 90 opens and closes under the control of the controller 900, and includes a high-pressure detector 901 interposed in the discharge pipe 51 and a low-pressure pressure interposed in the suction pipe 58. The detector 902 is input to the controller 900, and is opened and closed based on the difference P1-P2 between the high pressure P1 and the low pressure P2 taken from the detectors 901, 902. The predetermined value P for switching the open / close state is, for example, about 1.5 kg / cm ² .
[0018]
In this way, as shown in FIG. 2, it is determined whether or not the pressure difference P1-P2 is lower than the predetermined value P from the start of the refrigeration apparatus (step a). The refrigerant after cooling the compressor motor 10 is discharged to the low pressure region through the first drain passage 71 (step b). At the time of this low differential pressure, the discharge side is a low pressure region with respect to the high pressure liquid region on the cooling refrigerant supply side, and the differential pressure therebetween can be ensured to the maximum. Thus, the cooling refrigerant can be smoothly flowed, and cooling of the compressor motor 10 can be ensured even when the differential pressure is low.
[0019]
On the other hand, when the pressure difference in the step a is not less than the predetermined value, the on-off valve 91 is closed (step c), and the refrigerant after cooling the compressor motor 10 is compressed through the second drain passage 72. The air is discharged to the intermediate pressure range after the intake and closing of the machine 1, and the normal operation is performed (step d). For this reason, it is possible to prevent the compressor 1 from being cooled by the liquid refrigerant while preventing the intake air volume of the compressor 1 from being hindered and suppressing the decrease in the refrigerating capacity.
[0020]
In the above, as shown in FIG. 1, the second refrigerant supply passage 84 is connected between the downstream portion of the check valve 92 in the second drain passage 72 and the refrigerant supply passage 7. The liquid refrigerant can be directly injected into the intermediate port 13 of the compressor 1 by opening the injection operation on / off valve 85 including an electromagnetic valve interposed in the middle thereof.
[0021]
Further, in the above, the high pressure detector 901 and the low pressure detector 902 are provided separately for detecting the high / low differential pressure. However, the high / low pressure detector 902 is separately provided between the discharge pipe 51 and the suction pipe 54. A differential pressure detector that detects the differential pressure may be interposed. Further, instead of detecting the pressure, the pressure differential pressure may be detected by detecting the discharge gas temperature and the suction gas temperature, and there are various means for detecting the pressure differential.
[0022]
Further, in the above, a so-called heat pump type that switches between cooling and heating is shown, but it can be similarly applied to a cooling only machine or a heating only machine, and the heat source side heat exchanger 2 is an air cooling type. However, the use-side heat exchanger 4 is a dry type, but it is not limited whether it is air-cooled or liquid-cooled. Further, the compressor 1 may be of a scroll type, A rotary type may be used, and the type of the compressor is not particularly limited.
[0023]
【The invention's effect】
According to the first aspect of the present invention, when the pressure difference between the suction side and the discharge side of the compressor 1 at the time of starting or the like is lower than a predetermined value, the refrigerant after cooling the compressor motor 10 is: Since it is discharged to the low pressure region through the first drain passage 71, the maximum differential pressure between the supply side and the discharge side of the cooling refrigerant can be secured, and the compressor motor 10 can be smoothly cooled. to be able to flow a refrigerant, it is possible to ensure the cooling of the motor 10, also during normal operation of the differential pressure which is the pressure difference between the suction side of the compressor 1 discharge side becomes the predetermined value or more The refrigerant after cooling the compressor motor 10 is discharged through the second drain passage 72 to the intermediate pressure region after the intake and closing of the compressor 1, so that the intake air amount of the compressor 1 is not hindered. Ensures cooling of compressor motor 10 with liquid refrigerant while suppressing decline in refrigeration capacity Rukoto can.
[0024]
According to the second aspect of the present invention, the refrigerant flowing through the main drain passage 70 is caused to flow to the first drain passage 71 by opening the on-off valve 91 at the time of low differential pressure such as at the time of starting, and the on-off valve 91 is turned on during normal operation. By closing, the refrigerant flowing in the main drain passage 70 can flow to the second drain passage 72 via the check valve 92, and the passage control can be easily performed by one on-off valve 91 and one check valve 92. Can also be simplified.
[Brief description of the drawings]
FIG. 1 is a piping diagram showing an embodiment of a refrigeration apparatus according to the present invention.
FIG. 2 is a flowchart showing a control procedure of the refrigeration apparatus.
FIG. 3 is a piping diagram showing a conventional refrigeration apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Compressor, 10; Compressor motor, 2; Heat source side heat exchanger, 3; Expansion mechanism, 4; Utilization side heat exchanger, 7; Refrigerant supply passage, 70; Main drain passage, 71: First drain passage 72; second drain passage, 90; passage control mechanism, 91; on-off valve, 92; check valve

Claims (2)

A compressor (1), a heat source side heat exchanger (2), an expansion mechanism (3), and a use side heat exchanger (4) are provided for cooling the motor between the high pressure liquid region and the compressor motor (10). In the refrigeration apparatus connected to the refrigerant supply passage (7) for supplying the refrigerant, the first drain passage (71) for discharging the cooling refrigerant supplied to the compressor motor (10) to the low pressure region and the suction of the compressor (1) A second drain passage (72) for discharging to the intermediate pressure region after being closed, and the first drain when the pressure difference between the suction side and the discharge side of the compressor (1) falls below a predetermined value. drainage is discharged to the low pressure fluid zone via a passage (71), passage for draining the intermediate pressure region of the differential pressure is the predetermined value or more when the second drain passage (72) and through the compressor (1) A refrigeration apparatus comprising a control mechanism (90).   The first drain passage (71) and the second drain passage (72) are branched from the main drain passage (70) extending from the compressor motor (10), and the middle of the first drain passage (71). The refrigerating apparatus according to claim 1, wherein the opening / closing valve (91) is provided in the part and the check valve (92) is provided in the middle of the second drain passage (72) to constitute the passage control mechanism (90). .

Images