JPH03267592A - Hermetic rotary compressor - Google Patents

Abstract

PURPOSE:To enable appropriate switching between a serial two-stage operation and a parallel one-stage operation by driving compressors on the lower stage side and the higher stage side by separate motors and by providing an inlet pipe and a discharge pipe of the lower stage side and an inlet pipe of the higher stage side outside a hermetic shell, and a discharge pipe of the higher stage side in the hermetic shell. CONSTITUTION:In a hermetic shell 2, a lower stage side compression mechanism 4 and a high pressure side compression mechanism 5 driven by a lower stage side motor 3L and a higher stage side motor 3H are provided. An inlet pipe 4d and a discharge pipe 4e of the lower stage side and a high pressure side inlet pipe 5d are led to the outside of the hermetic shell 2, respectively, and a higher stage side discharge pipe 5e is opened in the hermetic shell 2. In the case of a high compression ratio where the pressure ratio between a condenser 11 and an evaporator 15 is large, direction of three-way valves 17 and 18 is set as shown for a serial two-stage operation, and when the compression ratio is not large, the three-way valves 17 and 18 are rotated by 90 deg. in the arrow direction as shown for a parallel operation. Or only the higher stage side is operated. Thus, simple manipulation enables switching to an appropriate operation according to load.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a hermetic rotary compressor that compresses circulating refrigerant in a refrigeration system or the like using a low-stage compression mechanism and a high-stage compression mechanism. When the ratio of evaporation pressure to condensation pressure (compression ratio) in the refrigeration cycle is large, such as in equipment or high-temperature heat pumps, the conventional one-stage Even if a two-stage compression device with two compressors installed in series is used, in this case the discharge gas of the lower-stage compressor exchanges heat directly or indirectly with high-pressure liquid refrigerant or intermediate-pressure two-phase refrigerant. Even if the cooled mold is sucked into the high-stage compressor and discharged there to a high pressure, this reduces the suction gas temperature of the high-stage compressor and prevents the discharge temperature from rising.a
In addition, by appropriately setting the compression ratios of the low-stage and high-stage compressors, each stage of the compressor can be operated under conditions with good efficiency, which improves the refrigeration cycle efficiency overall. Compressors capable of two-stage compression using two compressors have also been considered, such as the hermetic rotary two-stage compressor described in Japanese Patent Publication No. 53-9410. Equipped with a mechanism, the suction pipe on the low stage side and the discharge pipe on the high stage side are opened to the outside of the sealed shell, and the suction pipe on the high stage side is opened into the sealed shell, and the inside of the sealed shell is maintained at intermediate pressure. It is possible to perform two-stage compression operation with one motor, and when this is used in a refrigeration cycle, Two-phase refrigerant at high pressure or by indirect heat exchange to cool the refrigerant enters the hermetic shell, is sucked into the high-stage compression mechanism, is compressed to high pressure, and is discharged outside the hermetic shell, using two compressors. Although it is possible to achieve the same two-stage compression effect as in the case where the gas is inhaled in the lower stage and compressed and discharged in the higher stage, the problem that the invention aims to solve is that For example, when used in a high-temperature heat pump, it is suitable for high compression ratio operation where the load side is at a high temperature. When high capacity is required at a relatively low compression ratio, the heating capacity is increased by varying the motor rotation speed.The upper limit is limited by the motor rotation speed.
In addition, in the case of a two-stage compressor using two compressors, the equipment would become even larger, or the lower stage of the compressor oil could be distributed to the higher stage. An oil separator, oil return, etc. are also required.9 The present invention provides a hermetic rotary compressor that can realize two-stage compression with a simple configuration and can also be used in cases where high capacity is required. 4 Means for Solving the Problems The hermetic rotary compressor ζ of the present invention includes a low-stage suction pipe and a low-stage discharge pipe in which a low-stage compression mechanism, a high-stage compression mechanism, and motors for driving them separately are installed. , the high-stage suction pipes are each opened to the outside of the sealed shell, and the high-stage discharge pipe is opened to the inside of the sealed shell, and a discharge pipe is provided that communicates the inside of the sealed shell with the outside of the sealed shell. Preferably, the low-stage compression mechanism and the high-stage compression mechanism are in a positional relationship facing each other with the motor in between, and the high-stage discharge pipe and the discharge piping are in a positional relationship facing each other with the motor in between. Further, the discharge pipe and the low-stage discharge pipe can communicate with each other via a three-way valve, and the low-stage suction pipe and the high-stage suction pipe can communicate with each other through a three-way valve. More preferably, a check valve is provided between the three-way valve provided in the low stage discharge pipe and the discharge pipe. Two-stage compression operation (operation in which the low-stage side and high-stage side are connected in series) is advantageous for machine efficiency, and parallel one-stage compression operation (operation in which the low-stage side and high-stage side are connected in parallel) is advantageous when the capacity is high. ) can be achieved by simply switching between two three-way valves, and it is also possible to operate at a low capacity by operating only one compressor. The lubricating oil inside the sealed shell is smoothly supplied to both the low-ratio and high-stage compression mechanisms. The figure also shows one embodiment of the present invention, and shows a case in which a refrigeration cycle is constructed using the hermetic rotary compressor of the present invention.
is a nearly cylindrical sealed shell/k 3L is a sealed shell 2
The rotating shaft is the lower stage motor attached to the sealed shell 2.
L3H is the high-stage motor attached to the sealed shell 2, and its rotating shaft is located almost coincident with the central axis of the sealed shell 2. 4 and 5 are a low-stage compression mechanism and a high-stage compression mechanism attached to both ends of the sealed shell 2 so as to sandwich the motor 3L3H, and can be driven separately by the motors 3L and 3H, respectively.
, 5a are rotor holes provided integrally and eccentrically with the rotating shafts of the motors 3L and 3H, respectively; 4b and 5b are pistons mounted on the rotor shafts 4a and 5a, respectively;
4c, 5c are respective vanes, 6a, 6b,
7a.

7b and 8 and 9 are cylinders, respectively.
d is a suction pipe of the low-stage compression mechanism 4 (hereinafter referred to as low-stage suction pipe);
4e is a discharge pipe of the low-stage compression mechanism 4 (hereinafter referred to as low-stage discharge pipe);
5d is the suction pipe of the high-stage compression mechanism 5 (hereinafter referred to as the high-stage suction pipe)
45, each of which is led out to the outside of the sealed shell 2.
e is a discharge pipe of the high-stage compression mechanism 5 (hereinafter referred to as the high-stage discharge pipe);
11 is a condenser, the inlet of which is connected to the discharge pipe 12 provided in the sealed shell 2, and the outlet thereof is branched, with one end being an intermediate heat exchanger 13.
One is connected to the main throttle device 14 through the evaporator 15, and the other is connected to the intermediate heat exchanger 13 through the auxiliary throttle device 16.
．． 17 and 18 are three-way valves, and the three-way valve 17 is the low-stage discharge pipe 4.
The three-way valve 17 is provided on the piping connecting the intermediate heat exchanger 13 and the low-stage discharge pipe 4e, so that the low-stage discharge pipe 4e and the discharge pipe 12 or the low-stage discharge pipe 4e and the intermediate heat exchanger 13 can be connected by switching. A three-way valve 17 is provided between the
Even if a check valve 19 is provided for flow from the high-stage suction pipe 5d only to the discharge pipe 12, the three-way valve 18 is provided on the pipe connecting the high-stage suction pipe 5d and the intermediate heat exchanger 13.
The intermediate heat exchanger 13 or the high-stage suction pipe 5d and the low-stage suction pipe 4d can be switched and connected to the intermediate heat exchanger 13 via the pipe exiting the three-way valve 17 and the sub-throttle device 16. The condenser 11 exits the condenser 11 and connects to the main throttling device 14, where heat is exchanged indirectly and flows out to the three-way valve 18, resulting in a so-called two-stage compression system. Although the one-stage expansion cycle is formed, in such a configuration, the operation method will be explained first, but first of all, in the case of a high compression ratio where the ratio between the pressure of the condenser 11 and the pressure of the evaporator 15 is large, one-stage expansion cycle is performed. The valves 17 and 18 are set in the directions shown in the figure, and the motors 3L and 3H are operated to perform a series two-stage compression operation. In this case, the gas sucked in through the low-stage suction pipe 4d is compressed by the low-stage compression mechanism 4 to an intermediate pressure between the condenser 11 and the evaporator 15, and then exits from the sealed shell 2 through the low-stage discharge pipe 4e. Intermediate heat exchanger 13 via three-way valve 17
Here, the discharge gas is cooled by joining with the gas-liquid two-phase refrigerant (described later) discharged from the sub-throttle device 16, and is sucked into the high-stage suction pipe 5d via the three-way valve 18. In 5, the gas is compressed from intermediate pressure to high pressure, is discharged into the sealed shell 2 from the high-stage discharge pipe 5e, cools the coils of the motors 3L and 3H while passing through the gap between the motors 3L and 3H, and is discharged from the discharge pipe 12. is liquefied in the condenser 11, and part of it flows into the intermediate heat exchanger 13 at high pressure, and the rest is throttled to intermediate pressure in the sub-throttle device 16 as described above, and enters the intermediate heat exchanger 13 in a gas-liquid two-phase state. The cooled high-pressure liquid refrigerant is throttled down to low pressure by the main throttling device 14 and converted into endothermic air by the evaporator 15. Even if it is sucked into the low-stage suction pipe 4d again, two-stage compression is performed in series in this way. Especially when the compression ratio is high, the adiabatic efficiency of the compression mechanisms of the low-stage and high-stage compression mechanisms is compared to that when compression is performed in one stage. This includes the effect of reducing the enthalpy of high-pressure liquid refrigerant, making it possible to realize a highly efficient refrigeration cycle.Furthermore, since the low-ratio and high-ratio stages can be operated by separate motors, cycle control such as adjusting intermediate pressure can be achieved. In addition, with the configuration of the present invention, the pressure (high pressure) of the condenser 11 can be maintained inside the hermetic shell 2, so it goes without saying that the piston can be used not only in the low-stage compression mechanism 4 but also in the high-stage compression mechanism 5. The lubricating oil in the sealed shell 2 is smoothly supplied to metal contact parts such as between the vane 5a and the vane 5C, and problems such as seizure do not occur.1. %
In addition, the motors 3H and 3L are positioned in the center of the sealed shell 2, the low stage compression mechanism 4 and the high stage compression mechanism 5 are positioned so as to sandwich the motors 3H and 3L, respectively, and the high stage discharge pipe 5e and the discharge pipe 12 are connected to the motors. Since 3H and 3L are placed facing each other, it is possible to cool both motors during two-stage operation with a small number of piping. If a large amount of water is required, turn the three-way valve 17.
By doing so, the low-stage suction pipe 4d and the high-stage suction pipe 5d communicate with each other, and the low-stage discharge pipe 4e and the high-stage discharge pipe 5e communicate with each other. Gas is sucked into the low-stage suction pipe 4d and the high-stage suction pipe 5d in parallel, and the refrigerant compressed by the low-stage compression mechanism 4 is discharged from the discharge pipe via the low-stage discharge pipe 4e, the three-way valve 17, and the check valve 19. 1
The refrigerant compressed by the high-stage compression mechanism 5 enters the sealed shell 2 through the high-stage discharge pipe 5e, passes through the gap in the motor 3, cools the motor 3, and flows out from the discharge pipe 12. The refrigerant liquefied in the condenser 11 joins with the refrigerant discharged from the low-stage compression mechanism 4 and flows into the condenser 11.The three-way valves 17 and 18 of the refrigerant are closed to the intermediate heat exchanger 13. Therefore, the flow does not flow toward the sub-throttle device 16, but flows from the main throttle device 14 to the evaporator 15 via the intermediate heat exchanger 13.
Even if the refrigerant is sucked into the low-stage suction pipe 4d and the high-stage suction pipe 5d again, one-stage compression can be performed in this way.As is clear from the refrigerant flow, there are two compression mechanisms, low-stage and high-stage. The capacity of the refrigeration cycle can be greatly increased because the amount of compressed and discharged gas can be increased.
It is clear that the capacity can be further improved by increasing the rotation speed of L and 3H. Also, the low stage motor 3L is stopped and only the high stage motor 3H is operated, so that only the high stage compression mechanism 5 is operated. Although it is possible, in this case, the gas compressed by the high-stage compression mechanism 5 will flow out of the closed shell 2 from the discharge pipe 12 while cooling the high-stage motor 3H. No discharge gas flows into the stage side compression mechanism 4,
No reduction in capacity or accumulation of refrigerant occurs, and it is possible to cope with operating conditions with low capacity.The low-stage compression mechanism 4 and the high-stage compression mechanism 5 are located opposite each other with the motors 3H and 3L in between. Since the high stage discharge pipe 5e and the discharge pipe 12 are positioned opposite to each other with the motors 3H and 3L in between, each motor 3)L and 3L can be cooled even in the case of one stage with a small number of pipes. Also, in the case of these one-stage operations, the pressure (high pressure) in the condenser 11 can be maintained in the sealed shell 2, so that the piston 4a in the low-stage compression mechanism 4 and the high-stage compression mechanism 5 is
, 5a and the vanes 4c, 5c, etc., the lubricating oil in the sealed shell 2 is smoothly supplied, and problems such as seizure do not occur.l,% In this way, the simple operation of switching the three-way valve 17. The series two-stage compression and the parallel one-stage compression can be switched with just an operation, allowing appropriate and safe operation depending on the situation such as high compression ratios, small capacity units, high capacity, etc. From the three-way valve 17 to the discharge pipe 12 direction Since a check valve 19 is provided on the piping between them, the refrigerant flows back from the condenser 11 through the three-way valve 17 to the low-stage discharge pipe 4e when switching from two-stage series compression to one-stage parallel compression. This prevents the sudden pressure from being applied to the discharge valve (not shown) of the low-stage compression mechanism 4, thereby improving reliability. The hermetic rotary compressor ζ of the invention is equipped with a low-stage compression mechanism, a high-stage compression mechanism, and motors that drive them separately; a low-stage suction pipe;
The low-stage discharge pipe and the high-stage suction pipe are each opened outside the sealed shell, and the high-stage discharge pipe is opened inside the sealed shell.Discharge piping is provided to communicate between the inside of the sealed shell and the outside of the sealed shell, preferably with a low The stage-side compression mechanism and the high-stage compression mechanism are in a positional relationship facing each other with the motor in between, and the high-stage discharge pipe and the discharge piping are in a positional relationship facing each other with the motor in between. and the low-stage discharge pipe can communicate with each other through a three-way valve, and the low-stage suction pipe and the high-stage suction pipe can communicate with each other through a three-way valve, and more preferably, the three-way valve provided on the low-stage discharge pipe and the discharge pipe can communicate with each other through a three-way valve. Since a check valve is installed between the pipes, it is possible to switch between series two-stage compression and parallel one-stage compression with the simple operation of switching the three-way valve. High efficiency operation at compression ratio, high capacity operation at startup, etc.
Appropriate operation can be performed depending on the situation, and since the condenser pressure can be maintained inside the sealed shell during both operations, the compression mechanism can be smoothly lubricated, resulting in a highly reliable compressor. By providing a check valve between the three-way valve installed in the discharge pipe and the discharge pipe, when switching from series two-stage compression to parallel one-stage compression, refrigerant will not flow back into the low-stage discharge pipe, resulting in low This further improves reliability by preventing sudden pressure from being applied to the discharge valve of the stage-side compression mechanism.

[Brief explanation of drawings]

Claims (5)

[Claims] (1) A low-stage compression mechanism, a high-stage compression mechanism, and motors that drive them separately are provided in the sealed shell of the compressor, and the low-stage suction pipe, low-stage discharge pipe, and high-stage suction pipe are each sealed as described above. A hermetic rotary compressor, characterized in that a high-stage discharge pipe is opened to the outside of the shell, and a high-stage discharge pipe is opened to the inside of the hermetic shell, and a discharge pipe is provided that communicates the inside of the hermetic shell and the outside of the hermetic shell. . (2) The hermetic rotary compressor according to claim 1, wherein the low-stage compression mechanism and the high-stage compression mechanism are positioned opposite to each other with the motor in between. (3) The hermetic rotary compressor according to claim 1, characterized in that the high-stage discharge pipe and the discharge pipe are positioned opposite to each other with the motor in between. (4) In claim 1, a three-way valve is provided in the low-stage discharge pipe to enable communication between the discharge pipe and the low-stage discharge pipe via the three-way valve, and a three-way valve is further provided in the high-stage suction pipe. ,
A hermetic rotary compressor, characterized in that the low-stage suction pipe and the high-stage suction pipe can communicate with each other via the three-way valve. (5) The hermetic rotary compressor according to claim 4, further comprising a check valve provided between the three-way valve provided in the low-stage discharge pipe and the discharge pipe.