COOLING SYSTEM

Abstract

 According to the present invention, According to the present invention, a cooling system is provided which comprises: a compressor for compressing refrigerant; a condenser for condensing the refrigerant which is compressed by said compressor; an expansion valve for expanding the refrigerant which is condensed by said condenser; an evaporator for evaporating the refrigerant which is expanded by said expansion valve; a suction pressure-regulating valve which is installed to a refrigerant inflow tube connecting between said compressor and said evaporator and which allows the refrigerant supplied from said evaporator to said compressor to have a pressure lower than a predetermined pressure for preventing said compressor from being overloaded, wherein said suction pressure-regulating valve is set to supply the amount of the refrigerant which is less than amount of refrigerant corresponding to compression capacity of said compressor; and, an unloading part being installed to said refrigerant inflow tube in parallel with said suction pressure-regulating valve and including a bypass tube for an unloaded operation and an opening/closing-valve for said bypass tube, wherein said bypass tube has a supply amount of the refrigerant, which is equivalent to a difference between the supply amount of the refrigerant corresponding to the compression capacity of said compressor and the supply amount of the refrigerant through said suction pressure regulating valve, wherein said unloading part makes it possible to attain the unloaded operation by closing said bypass tube by means of said opening/closing-valve, to thereby supply the refrigerant to said compressor only through said suction pressure regulating valve upon an initial startup or a re-startup of said compressor, so that the amount of the refrigerant flowing through said suction pressure regulating valve is less than the amount of the refrigerant corresponding to the compression capacity of said compressor and, wherein said unloading part makes it possible to attain a normal operation by opening said bypass tube by means of said opening/closing-valve, to thereby supply the refrigerant to said compressor through said suction pressure regulating valve and said bypass tube while in a normal operation of said compressor after a certain period from the initial startup, so that the amount of the refrigerant in the normal operation is equivalent to the amount of the refrigerant corresponding to the compression capacity of said compressor.

Description

Field of the Invention

[0001] The present invention is related a cooling system, and more particularly to a cooling system for a freezer vehicle, an air conditioner and a refrigerator, wherein an unloaded operation is possible by decreasing flow rate of refrigerant into a compressor upon an initial startup of a compressor or upon a re-startup after an interruption, and by increasing flow rate of refrigerant into the compressor during an normal operation to match it with a compression capacity of the compressor. Thereby, the efficiency of the compressor in the operation is improved and damage due to liquid hammering is prevented.

Background of the Invention

[0002] Generally, as disclosed in KR 20-0300275, a cooling system comprises a compressor for compressing circulating-refrigerant to have a high pressure, a condenser for condensing the compressed refrigerant with a high temperature, an expansion valve for expanding condensed refrigerant to have a low temperature, and an evaporator for evaporating expanded refrigerator with low temperature to thereby cool down ambient air. The cooling system is used for a freezer vehicle, an air conditioner and a refrigerator.

[0003] As disclosed in KR 10-1270208, the conventional cooling system comprises a valve for regulating suction pressure (SPR valve or CPR valve) disposed between an evaporator and a compressor. Accordingly, the refrigerant is supplied to the compressor while the refrigerant pressure is maintained below a predetermined level to thereby improve the compression efficiency, wherein the refrigerant has a high pressure state other than a low pressure state, because defrosting is unavailable due to frost generated in the evaporator.

[0004] On the other hand, as disclosed in KR 10-0201689, the conventional cooling system comprises an unloading valve which is integrated with a compressor for compressing refrigerant. Thus, upon an initial startup of a compressor or upon a re-startup after an interruption of operation, a load at an initial startup is minimized, to thereby prevent fatigue accumulation in the compressor.

[0005] In the above-stated cooling systems, it is impossible to apply the unloading valve to the compressor that is commonly manufactured to have a closed-type, because the unloading valve should be integrated into the inner side of a compressor crankcase. Also, the manufacturing cost increases due to complex structure of the unloading valve.

The Object of the Invention

[0006] Therefore, an object of the present invention is to provide a cooling system comprising a suction pressure regulating valve and an unloading part, which are in parallel with each other and which are installed to a refrigerant inflow tube between a compressor and an evaporator, wherein the refrigerant through the suction pressure regulating valve, the amount of which is less than the compression capacity of the compressor, is supplied to the compressor in a closed state of the unloading part upon initial startup or re-startup of the compressor, and wherein the amount of the refrigerant equivalent to a full capacity of the compressor is supplied to the compressor through the suction pressure regulating valve and the unloading part, while the unloading part is opened in a normal operation, so that an unloaded operation is enabled, which minimizes an operation load of the compressor.

[0007] The other object of the present invention is to provide a cooling system comprising a suction pressure regulating valve for supplying refrigerant, an unloading part and a loading part, wherein said suction pressure regulating valve is installed to a refrigerant inflow tube between a compressor and an evaporator or to a refrigerant inflow tube and supplies the refrigerant, the amount of which is equivalent to compression capacity of a compressor, wherein said unloading part and said loading part are installed at an exit end of the suction pressure regulating valve in parallel with each other for supplying the refrigerant, the amount of which is less than the compression capacity of the compressor, wherein the amount of the refrigerant less than the compression capacity of the compressor is supplied to the compressor through the loading part, while the unloading part is closed upon an initial startup or a re-startup of the compressor, and wherein the amount of the refrigerant equivalent to the compression capacity of the compressor is supplied to the compressor through the unloading part and the loading part, while the unloading part is open in a normal operation. Thereby, an unloaded operation is enabled which minimizes an operation load of the compressor. Also, even in the normal operation of the compressor, the refrigerant that is adjusted to have a constant level of a pressure by the suction pressure regulating valve is supplied to the compressor to thereby improve compression efficiency.

[0008] The objects of the present invention are restricted to the above-described ones, and other objects that are not described herein may be readily understood by one of ordinary skill in the art with reference to the description herein-below.

[0009] According to the present invention, a cooling system is provided which comprises: a compressor for compressing refrigerant; a condenser for condensing the refrigerant which is compressed by said compressor; an expansion valve for expanding the refrigerant which is condensed by said condenser; an evaporator for evaporating the refrigerant which is expanded by said expansion valve; a suction pressure-regulating valve which is installed to a refrigerant inflow tube connecting between said compressor and said evaporator and which allows the refrigerant supplied from said evaporator to said compressor to have a pressure lower than a predetermined pressure for preventing said compressor from being overloaded, wherein said suction pressure-regulating valve is set to supply the amount of the refrigerant which is less than amount of refrigerant corresponding to compression capacity of said compressor; and, an unloading part which is installed to said refrigerant inflow tube in parallel with said suction pressure-regulating valve and which includes a bypass tube for an unloaded operation and an opening/closing-valve for said bypass tube, wherein said bypass tube has a supply amount of the refrigerant, which is equivalent to a difference between the supply amount of the refrigerant corresponding to the compression capacity of said compressor and the supply amount of the refrigerant through said suction pressure regulating valve, wherein said unloading part makes it possible to attain the unloaded operation by closing said bypass tube by means of said opening/closing-valve, to thereby supply the refrigerant to said compressor only through said suction pressure regulating valve upon an initial startup or a re-startup of said compressor, so that the amount of the refrigerant flowing through said suction pressure regulating valve is less than the amount of the refrigerant corresponding to the compression capacity of said compressor and, wherein said unloading part makes it possible to attain a normal operation by opening said bypass tube by means of said opening/closing-valve, to thereby supply the refrigerant to said compressor through said suction pressure regulating valve and said bypass tube while in a normal operation of said compressor after a certain period from the initial startup, so that the amount of the refrigerant in the normal operation is equivalent to the amount of the refrigerant corresponding to the compression capacity of said compressor.

[0010] Here, said suction pressure regulating valve supplies the refrigerant to the compressor in such a way that the amount of the refrigerant through the said suction pressure regulating valve is equivalent to 40 % - 80% of the amount of the refrigerant corresponding to the compression capacity of the compressor.

[0011] Also, said bypass tube supplies the refrigerant to the compressor in such a way that the amount of the refrigerant through the said bypass tube is equivalent to 60 % - 20% of the amount of the refrigerant corresponding to the compression capacity of the compressor.

[0012] Also, according to the present invention, a cooling system is provided which comprises: a compressor for compressing refrigerant; a condenser for condensing the refrigerant which is compressed by said compressor; an expansion valve for expanding the refrigerant which is condensed by said condenser; an evaporator for evaporating the refrigerant which is expanded by said expansion valve; a suction pressure-regulating valve for supplying the amount of the refrigerant equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor, said suction pressure-regulating valve being installed to a refrigerant inflow tube between said compressor and said evaporator or to a refrigerant inflow tube; and an unloading part and a loading part which are installed at an exit of said compressor in parallel with each other for supplying the amount of the refrigerant less than the amount of the refrigerant corresponding to the compression capacity of the compressor, wherein an unloaded operation of the compressor is possible by supplying through the loading part the amount of the refrigerant that is less than the amount of the refrigerant corresponding the compression capacity of the compressor while the unloading part is closed upon an initial startup or re-startup of the compressor, and wherein a normal operation of the compressor is possible by supplying through the unloading part and the loading part the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor while the unloading part is open after a certain period from the initial startup or the re-startup.

[0013] Here, said loading part comprises a loading tube, which has such a diameter as to supply to the compressor the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to 40 %-80 % of the compression capacity of the compressor.

[0014] Also, said unloading part comprises a bypass tube and a valve for opening and closing said bypass tube, wherein said bypass tube has such a diameter as to supply the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to 60 %-20 % of the compression capacity of the compressor.

The Effect of the Invention

[0015] Therefore, in the present invention, the suction pressure regulating valve and the unloading part being in parallel with each other are installed to the refrigerant inflow tube between the compressor and the evaporator, so that the refrigerant, the amount of which is less than the compression capacity of the compressor, is supplied to the compressor through the suction pressure regulating valve in a closed state of the unloading part upon the initial startup or the re-startup of the compressor. In the normal operation, the amount of the refrigerant corresponding to the full capacity of the compressor is supplied to the compressor through the suction pressure regulating valve and the unloading part, while opening the unloading part. Thus, it is possible to provide the cooling system enabling the unloaded operation, which minimizes an operation load of the compressor.

[0016] Also, the suction pressure regulating valve, which supplies the amount of the refrigerant corresponding to the compression capacity of the compressor, is installed to the refrigerant inflow tube between the compressor and the evaporator or the refrigerant inflow tube. In addition, the unloading part and a loading part being in parallel with each other, each of which supplies the amount of the refrigerant less than the amount of the refrigerant corresponding to the compression capacity of the compressor, are installed at an outlet of the suction pressure regulating valve. Accordingly, upon the initial startup or the re-startup of the compressor, the amount of the refrigerant less than the refrigerant corresponding to the compression capacity of the compressor is supplied to the compressor through the loading part, while the unloading part is closed. In the normal operation, the amount of the refrigerant being equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor is supplied to the compressor through the loading part and the unloading part, while the unloading part is open. Thereby, it is possible to attain the unloaded operation, which minimizes the operation load of the compressor. Also, even in the normal operation of the compressor, it is possible to supply to the compressor the refrigerant, the pressure of which is adjusted below a certain level of pressure by means of the suction pressure regulating valve. Thus, it is possible to improve the compression efficiency.

[0017] Meanwhile, the effects of the present invention are not restricted to the above-described ones and other effects that are not described herein can be clearly understood by one of ordinary skill in the art from the recitations in the claims.

Brief Description of Drawings

[0018] 

Figure 1 is a schematic view of the cooling system according to a preferred embodiment of the present invention.

Figure 2 is a schematic view showing a flow of refrigerant during an unloaded operation of a compressor in the cooling system in Figure 1.

Figure 3 is a schematic view showing a flow of refrigerant during a normal operation of the compressor in the cooling system in Figure 1.

Figure 4 is a schematic view of the cooling system according to a variant of the preferred embodiment of the present invention.

Best Mode of the Embodiments

[0019] Herein below, a preferred embodiment of the present invention will be detailed with reference to the drawings.

[0020] Figure 1 is a schematic view of the cooling system according to a preferred embodiment of the present invention. Figure 2 is a schematic view showing a flow of refrigerant during an unloaded operation of a compressor in the cooling system in Figure 1. Figure 3 is a schematic view showing a flow of refrigerant during a normal operation of the compressor in the cooling system in Figure 1. Figure 4 is a schematic view of the cooling system according to a variant of the preferred embodiment of the present invention.

[0021] As shown in Figures 1-3, a cooling system according to a preferred embodiment of the present invention comprises: a compressor (110) for compressing refrigerant; a condenser (120) for condensing the refrigerant which is compressed by said compressor (110); an expansion valve (130) for expanding the refrigerant which is condensed by said condenser (120); an evaporator (140) for evaporating the refrigerant which is expanded by said expansion valve (130); a suction pressure-regulating valve (150) which is installed to a refrigerant inflow tube (111) connecting between said compressor (110) and said evaporator (130) and which allows the refrigerant supplied from said evaporator (140) to said compressor (110) to have a pressure lower than a predetermined pressure, wherein said suction pressure regulating valve prevents said compressor (110) from being overloaded and wherein said suction pressure-regulating valve is set to supply the amount of the refrigerant which is less than amount of refrigerant corresponding to compression capacity of said compressor (110); and, an unloading part (160) which is installed to said refrigerant inflow tube (111) in parallel with said suction pressure-regulating valve (150) and which includes a bypass tube (161) for an unloaded operation and an opening/closing-valve (162) for said bypass tube (161), wherein said bypass tube (161) has a supply amount of the refrigerant, which is equivalent to a difference between the supply amount of the refrigerant corresponding to the compression capacity of said compressor (110) and the supply amount of the refrigerant through said suction pressure regulating valve (150), wherein said unloading part (160) makes it possible to attain the unloaded operation by closing said bypass tube (161) by means of said opening/closing-valve (162), to thereby supply the refrigerant to said compressor (110) only through said suction pressure regulating valve (150) upon an initial startup or a re-startup of said compressor (110), so that the amount of the refrigerant flowing through said suction pressure regulating valve (150) is less than the amount of the refrigerant corresponding to the compression capacity of said compressor (110) and, wherein said unloading part (160) makes it possible to attain a normal operation by opening said bypass tube (161) by means of said opening/closing-valve (162), to thereby supply the refrigerant to said compressor (110) through said suction pressure regulating valve (150) and said bypass tube (161) while in a normal operation of said compressor (110) after a certain period from the initial startup, so that the amount of the refrigerant in the normal operation is equivalent to the amount of the refrigerant corresponding to the compression capacity of said compressor (110).

[0022] The compressor (110) is driven by a drive pump (110A) to thereby compress the refrigerant to have a high temperature and a high pressure, wherein the drive pump (110A) is driven by electric power means. The compressor (110) receives the refrigerant through the refrigerant inflow tube (111), the refrigerant being discharged from the evaporator (140). Thereafter, the compressor (110) compresses the refrigerant and supplies the refrigerant to the condenser (120) through a refrigerant discharging tube (112) connected to the condenser (120).

[0023] Here, if the cooling system is applied to the freezer vehicle, the compressor (110) is driven by an electric motor; otherwise, the compressor (110) is connected to a driving axis of a separate engine through a flywheel and a belt, so that it receives a driving force when the engine is driven.

[0024] The condenser (120) condenses the compressed refrigerant, which is supplied from the refrigerant discharging tube (112) of said compressor (110), into a liquid state with a median temperature and a high pressure by means of air cooling. Then, the condenser (120) cools down and condenses the refrigerant by means of the air cooling, while using a condenser fan (120A). Thereafter, the refrigerant is supplied to the expansion valve (130) through a liquid receiver (RT), such as a receiver tank. Preferably, a dehumidifier (DR), such as a drier is further installed at an end of said liquid receiver (RT) to thereby remove water contained in the refrigerant supplied to the expansion valve (130).

[0025] The expansion valve (130) expands the refrigerant, which is condensed by said condenser (120), to turn it into a gas state having a low temperature and a low pressure. The expansion valve (130) receives the condensed refrigerant from the liquid receiver (RT) which stores the refrigerant condensed by the condenser (120).

[0026] The evaporator (140) evaporates the refrigerant, which is expanded by the expansion valve (130), using an evaporation fan (140A) to thereby cool ambient air. Thereafter, the evaporator (140) supplies the refrigerant to the refrigerant inflow tube (111) of the compressor (110) to thereby make the low temperature-refrigerant to have a constant temperature.

[0027] Preferably, a sensitive heat tube (SB) is wrapped in heating coils (HT) at an exit of the evaporator (140), so that the expansion valve (130) is adjusted to open/close according to the temperature and the pressure of the refrigerant due to evaporation in the evaporator (140).

[0028] Preferably, an accumulator (ACC) is arranged at an outlet of said evaporator (140), wherein said accumulator stores water contained in the liquid-state refrigerant so as to prevent the water from being supplied to the compressor (110), whereas said accumulator supplies only the gas-state refrigerant to the compressor (110).

[0029] Said suction pressure regulating valve (150) is CPR valve (Crankcase Pressure Regulating valve) or SPR valve (Suction Pressure Regulating valve). Said suction pressure regulating valve is installed to the refrigerant inflow tube (111), to thereby allow the refrigerant supplied from the evaporator (140) to the compressor (110) to have a pressure below a predetermined level of the pressure. Thereby, it prevents the compressor (110) from being overloaded. Also, said suction pressure regulating valve (150) sets a supply amount of the refrigerant in such a way that it supplies the refrigerant, amount of which is less than the compression capacity of the compressor (110).

[0030] Here, the suction pressure regulating valve (150) controls the amount of the refrigerant by adjusting its diameter with the use of adjusting means in such a way that the amount of the refrigerant flowing from the evaporator (140) to the refrigerant inflow tube (111) is less than the amount of the refrigerant corresponding to the compression capacity of the compressor (110). For example, the amount of the refrigerant supplied from the refrigerant inflow tube (111) to the compressor (110) is reduced in such a way that the amount of the refrigerant thorough the suction pressure regulating valve (150) is equivalent to 40 % - 80 % of the amount of the refrigerant corresponding to the compression capacity of the compressor (110).

[0031] Accordingly, upon an initial startup of the compressor (110) or upon a re-startup after interruption of the compressor (110), the refrigerant is supplied to the compressor (110) through the refrigerant inflow tube (111) in such a way that the amount of the refrigerant is equivalent to 40-80 % of the amount of the refrigerant during the normal operation. Thereby, the unloaded operation is possible by relieving a maximum load which may be momentarily generated in the drive pump (110A) or the compressor (110). Therefore, the accumulation of fatigue in the compressor (110) or the drive pump (110A) may be prevented and the durability thereof may be improved.

[0032] Here, if the amount of the refrigerant supplied to the compressor (110) through the suction pressure regulating valve (150) is less than 40 % relative to the compression capacity of the compressor (110), the pressure in the compressor (110) decreases greatly due to rapid decrease of the load. It causes the incorrect operation of the drive pump (110A), while splashing oil used in the drive pump (110A).

[0033] If the amount of the refrigerant supplied to the compressor (110) through the suction pressure regulating valve (150) exceeds by 80 % relative to the compression capacity of the compressor (110), it is impossible to significantly relieve the load resulting from the amount of the refrigerant supplied to the compressor (110). Thus, an effect for momentarily relieving the maximum load cannot be obtained, and thus, it is impossible to provide the effect of the unloaded operation.

[0034] Therefore, by means of the suction pressure regulating valve (150), the amount of the refrigerant supplied from the refrigerant inflow tube (111) to the compressor (110) is reduced by 40-80% relative to the compression capacity of the compressor. Thereby, upon the initial startup of the compressor (110) or the re-startup after interruption, it is possible to provide the effect of the unloaded operation, while preventing the incorrect operation of the drive pump (110A).

[0035] Here, the suction pressure regulating valve (150), which comprises the CPR valve or the SPR valve, is well known in the field of art. Accordingly, the detailed description will not be provided herein with respect thereto.

[0036] Said unloading part (160) provides the unloaded operation by supplying the amount of the refrigerant, which is less than the amount of the refrigerant corresponding to the compression capacity of the compressor (110), from the evaporator (140) to the compressor (110), upon the initial startup or the re-startup after interruption of the compressor (110). On the other hand, said unloading part (160) provides the normal operation by supplying the amount of the refrigerant, which is equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor, from the evaporator (140) to the compressor (110) while in the normal operation of the compressor (110). The unloading part (160) is installed to the refrigerant inflow tube (111) in parallel with the suction pressure regulating valve (150). The unloading part (160) comprises the bypass tube (161) for the unloaded operation and the valve (162) for opening/closing the bypass tube (161), wherein the bypass tube (161) allows the amount of the refrigerant, which is equivalent to the difference between the amount of the refrigerant corresponding to the compression capacity of the compressor (110) and the amount of the refrigerant through the suction pressure regulating valve (150).

[0037] Preferably, said opening/closing valve (162) comprises a solenoid valve, a PWM valve, an electronic proportional control valve, etc. The opening/closing valve (162) operates to open/close in accordance with an electronic signal.

[0038] Accordingly, upon the initial startup or upon the re-startup of the compressor (110), said opening/closing valve (162) closes the bypass tube (161) in accordance with a control signal from the control means, to thereby supply the refrigerant to the compressor (110) only through the suction pressure regulating valve (150), wherein the amount of the refrigerant through the valve (150) is less than the amount of the refrigerant corresponding to the compression capacity of the compressor (111). Thus, the unloaded operation is enabled. When the compressor (110) operates with a normal speed after a certain period from the startup, the opening/closing valve (162) opens the bypass tube (161) in accordance with a control signal from the control means. Thus, the amount of the refrigerant corresponding to the compression capacity of the compressor (110) can be supplied to the compressor (110) through the suction pressure regulating valve (150) and the bypass tube (161) to thereby enable the normal operation.

[0039] Here, if the amount of the refrigerant though the suction pressure regulating valve (150) is equivalent to 40-80 % of the amount of the refrigerant corresponding to the compression capacity of the compressor (110), the bypass tube (161) may be configured to have such a diameter as to supply the amount of the refrigerant, which is equivalent to 60-20 % of the amount of the refrigerant corresponding to the compression capacity of the compressor (110). Thereby, while in the normal operation, the amount of the refrigerant corresponding to 100 % of the compression capacity of the compressor (110) can be supplied to the compressor (110).

[0040] Specifically, if the amount of the refrigerant supplied through the suction pressure regulating valve (150) is set to correspond to 60 % of the compression capacity of the compressor (110), the diameter of the bypass tube (161) is configured so as to supply the amount of the refrigerant corresponding to 40 % of the compression capacity of the compressor (110). Thereby, the amount of the refrigerant corresponding to 100 % of the compression capacity of the compressor (110) is supplied to the compressor (110) while in the normal operation

[0041] Accordingly, with the use of the unloading part (160), the bypass tube (161) is closed upon the initial startup or the re-startup after the interruption of the compressor (110), so that a small amount of the refrigerant is supplied to the compressor (110) only through the suction pressure regulating valve (150) to thereby achieve the unloaded operation of the compressor (110). While in the normal operation of the compressor (110), the bypass tube (161) opens to allow the amount of the refrigerant corresponding to the compression capacity of the compressor (110) to be supplied to the compressor (110) through the suction pressure regulating valve (150) and the bypass tube (161).

[0042] Herein-below, the description will be provided with respect to the operation and the effects of the cooling system according to the preferred embodiment of the present invention.

[0043] If the compressor (110) starts to operate or re-starts after the interruption of the normal operation, the opening/closing valve (162) in the unloading part (160) is controlled to close the bypass tube (161) by the control means for controlling the compressor (110) or the drive pump (110A) as shown in Figure 2.

[0044] Here, the amount of the refrigerant flowing from the evaporator (140) to the compressor (110) is controlled to be equivalent to 40 %-80 % of the amount of the refrigerant corresponding to the compression capacity of the compressor (110) by means of the suction pressure regulating valve (150), Accordingly, the maximum load, which might be momentarily generated in the compressor (11) or the drive pump (110A), can be relieved to thereby allow the unloaded operation of the compressor (110). In this way, the accumulation of fatigue in the compressor (110) or the drive pump (110A) may be prevented and the durability thereof may be improved.

[0045] While the drive pump (110A) operates with the normal speed after the unloaded operation, the opening/closing valve (162) in the unloading part (160) is controlled to open the bypass tube (161) by means of the control means for controlling the compressor (110) or the drive pump (110A) as shown in Figure 3.

[0046] Here, while the amount of the refrigerant flowing from the evaporator (140) to the compressor (110) is controlled to be equivalent to 40 %-80 % of the amount of the refrigerant corresponding to the compression capacity of the compressor (110) by means of the suction pressure regulating valve (150), an addition of the refrigerant is obtained through the bypass tube (161), the amount of which is equivalent to 60 %- 20% of the amount of the refrigerant corresponding to the compression capacity of the compressor (110). Accordingly, the amount of the refrigerant corresponding to 100 % of the compression capacity of the compressor (110) can be supplied to the compressor, and thus, the compressor (110) or the drive pump (110A) can operate in the loaded operation (the normal operation).

[0047] Therefore, according to the above-described cooling system, the suction pressure regulating valve (150) and the unloading part (160) being in parallel with each other are installed to the refrigerant inflow tube (111) between the compressor (110) and the evaporator (140), so that the refrigerant, the amount of which is less than the compression capacity of the compressor (110), is supplied to the compressor (110) through the suction pressure regulating valve (150) in a closed state of the unloading part (160) upon the initial startup or the re-startup of the compressor (110). In the normal operation, the amount of the refrigerant corresponding to the full capacity of the compressor (110) is supplied to the compressor (110) through the suction pressure regulating valve (150) and the unloading part (160), while opening the unloading part (160). Thus, it is possible to provide the cooling system enabling the unloaded operation, which minimizes an operation load of the compressor (110).

[0048] In the preferred embodiment of the present invention described, the suction pressure control valve (150) and the unloading part (160) being in parallel with other are installed to the refrigerant inflow tube (111) between the compressor (110) and the evaporator (140), so that the refrigerant, the amount of which is less than the compression capacity of the compressor (110), is supplied to the compressor (110) through the suction pressure regulating valve (150) in a closed state of the unloading part (160) upon the initial startup or the re-startup of the compressor (110), whereas the refrigerant corresponding to the full capacity of the compressor (110) is supplied to the compressor (110) through the suction pressure regulating valve (150) and the unloading part (160) in an open state of the unloading part (160) in the normal operation. However, in a variant of the present invention shown in Figure 4, the suction pressure regulating valve (150), which supplies the amount of the refrigerant corresponding to the compression capacity of the compressor (110), is installed to the refrigerant inflow tube (111) between the compressor (110) and the evaporator (140) or the refrigerant inflow tube (111). Also, the unloading part (160) and a loading part (170) being in parallel with each other, each of which supplies the amount of the refrigerant less than the amount of the refrigerant corresponding to the compression capacity of the compressor (110), are installed at an outlet of the suction pressure regulating valve (150). Accordingly, upon the initial startup or the re-startup of the compressor (110), the amount of the refrigerant less than the refrigerant corresponding to the compression capacity of the compressor (110) is supplied to the compressor (110) through the loading part (170), while closing the unloading part (160). In the normal operation, the amount of the refrigerant being equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor (110) is supplied to the compressor (110) through the loading part (170) and the unloading part (160), while opening the unloading part (160). Thereby, it is possible to attain the unloaded operation, which minimizes the operation load of the compressor (110). Also, even in the normal operation of the compressor (110), it is possible to supply to the compressor (110) the refrigerant, the pressure of which is adjusted below a certain level of pressure by means of the suction pressure regulating valve (150). Thus, it is possible to prevent liquid hammering and to improve the compression efficiency.

[0049] Preferably, said suction pressure regulating valve (150) or said refrigerant inflow tube (111) allows the amount of the refrigerant, which is equivalent to the amount of the refrigerant corresponding to the capacity of the compressor (110), to be supplied to the compressor (110). Said loading part (170) comprises a loading tube (171), the diameter of which is configured in such a way that the amount of the refrigerant supplied to the compressor (110) through the loading tube (171) is equivalent to the amount of the refrigerant corresponding to 40 %-80 % of the compression capacity of the compressor (110). The bypass tube (161) in the unloading part (160) has the diameter which is configured in such a way that the amount of the refrigerant corresponding to 60%-20% of the compression capacity of the compressor (110) is supplied to the compressor (110) through the bypass tube (161).

[0050] Although the present invention has been described with reference to the specific embodiments, many variants thereof may be possible without departing from the scope of the present invention. Thus, the scope of the present invention shall be defined by the claims and the equivalents thereof, but not by the described embodiments.

Claims

1. A cooling system comprising:

a compressor (110) for compressing refrigerant;

a condenser (120) for condensing the refrigerant which is compressed by said compressor (110);

an expansion valve (130) for expanding the refrigerant which is condensed by said condenser (120);

an evaporator (140) for evaporating the refrigerant which is expanded by said expansion valve (130);

a suction pressure-regulating valve (150) which is installed to a refrigerant inflow tube (111) connecting between said compressor (110) and said evaporator (130) and which allows the refrigerant supplied from said evaporator (140) to said compressor (110) to have a pressure lower than a predetermined pressure for preventing said compressor (110) from being overloaded, wherein said suction pressure-regulating valve is set to supply the amount of the refrigerant which is less than amount of refrigerant corresponding to compression capacity of said compressor (110); and,

an unloading part (160) which is installed to said refrigerant inflow tube (111) in parallel with said suction pressure-regulating valve (150) and which includes a bypass tube (161) for an unloaded operation and an opening/closing-valve (162) for said bypass tube (161), wherein said bypass tube (161) has a supply amount of the refrigerant, which is equivalent to a difference between the supply amount of the refrigerant corresponding to the compression capacity of said compressor (110) and the supply amount of the refrigerant through said suction pressure regulating valve (150),

wherein said unloading part (160) makes it possible to attain the unloaded operation by closing said bypass tube (161) by means of said opening/closing-valve (162), to thereby supply the refrigerant to said compressor (110) only through said suction pressure regulating valve (150) upon an initial startup or a re-startup of said compressor (110), so that the amount of the refrigerant flowing through said suction pressure regulating valve (150) is less than the amount of the refrigerant corresponding to the compression capacity of said compressor (110) and,
wherein said unloading part (160) makes it possible to attain a normal operation by opening said bypass tube (161) by means of said opening/closing-valve (162), to thereby supply the refrigerant to said compressor (110) through said suction pressure regulating valve (150) and said bypass tube (161) while in a normal operation of said compressor (110) after a certain period from the initial startup, so that the amount of the refrigerant in the normal operation is equivalent to the amount of the refrigerant corresponding to the compression capacity of said compressor (110).

2. The cooling system as claimed in claim 1, characterized in that said suction pressure regulating valve (150) supplies the refrigerant to the compressor (110) in such a way that the amount of the refrigerant through the said suction pressure regulating valve (150) is equivalent to 40 % - 80% of the amount of the refrigerant corresponding to the compression capacity of the compressor (110).

3. The cooling system as claimed in claim 2, characterized in that said bypass tube (161) supplies the refrigerant to the compressor (110) in such a way that the amount of the refrigerant through the said bypass tube (161) is equivalent to 60 % - 20% of the amount of the refrigerant corresponding to the compression capacity of the compressor (110).

4. A cooling system comprising:

a compressor (110) for compressing refrigerant;

a condenser (120) for condensing the refrigerant which is compressed by said compressor (110);

an expansion valve (130) for expanding the refrigerant which is condensed by said condenser (120);

an evaporator (140) for evaporating the refrigerant which is expanded by said expansion valve (130);

a suction pressure-regulating valve (150) for supplying the amount of the refrigerant equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor (110), said suction pressure-regulating valve being installed to a refrigerant inflow tube (111) between said compressor (110) and said evaporator (140); and

an unloading part (160) and a loading part (170) which are installed at an exit of said suction pressure-regulating valve (150) in parallel with each other for supplying the amount of the refrigerant less than the amount of the refrigerant corresponding to the compression capacity of the compressor (110),

wherein an unloaded operation of the compressor (110) is possible by supplying through the loading part (170) the amount of the refrigerant that is less than the amount of the refrigerant corresponding the compression capacity of the compressor (110) while the unloading part (160) is closed upon an initial startup or re-startup of the compressor (110), and
wherein a normal operation of the compressor (110) is possible by supplying through the unloading part (160) and the loading part (170) the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to the compression capacity of the compressor (110) while the unloading part (160) is open after a certain period from the initial startup or the re-startup.

5. The cooling system as claimed in claim 4, characterized in that said loading part (170) comprises a loading tube (171), which has such a diameter as to supply to the compressor (110) the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to 40 %-80 % of the compression capacity of the compressor (110).

6. The cooling system as claimed in claim 5, characterized in that said unloading part (160) comprises a bypass tube (161) and a valve (162) for opening and closing said bypass tube (161), wherein said bypass tube (161) has such a diameter as to supply the amount of the refrigerant that is equivalent to the amount of the refrigerant corresponding to 60 %-20 % of the compression capacity of the compressor (110).

Drawing