JP5328697B2 - Two-stage compressor and heat pump device - Google Patents

Description

  The present invention relates to a two-stage compressor having two compression sections, and a heat pump device including the two-stage compressor.

  In the rotary compressor, the compressor sucks the refrigerant into the compression chamber and compresses it, and discharges it from the discharge port to the discharge space. Generally, the discharge port is provided with a discharge valve that opens due to a pressure difference between the pressure in the compression chamber and the pressure in the discharge space. In particular, when one end of the plate-shaped valve is fixed and the pressure in the compression chamber becomes higher than the pressure in the discharge space, a reed valve that is pushed from the compression chamber side and opens flexibly is provided as a discharge valve. There are many things.

Here, the opening area of the discharge port and the lift amount, which is the amount of deflection of the reed valve, are important factors for increasing the efficiency of the rotary compressor.
In a rotary compressor, if the opening area of the discharge port is small, the compressed refrigerant cannot be discharged completely and is recompressed, resulting in loss. On the other hand, when the opening area of the discharge port is large, the refrigerant accumulates in the discharge port portion when the refrigerant is discharged. The refrigerant accumulated in the discharge port is recompressed and a loss occurs.
In a rotary compressor, if the lift amount of the reed valve is small, the reed valve becomes a resistance when the compressed refrigerant is discharged, and loss occurs. On the other hand, if the reed valve lift is large, the reed valve closes slowly, so that the refrigerant once discharged is re-inhaled from the discharge port. The re-inhaled refrigerant is re-compressed and loss occurs. Further, if the lift amount is large, the valve may receive a large impact when the valve is closed and may be damaged.

The two-stage compressor includes two compression units (a low-stage compression unit and a high-stage compression unit) connected in series. Here, the exclusion volume of the high-stage compression unit is smaller than the exclusion volume of the low-stage compression unit. Therefore, if the opening area of the discharge port provided in the low-stage compression unit and the lift amount of the reed valve are the same as the opening area of the discharge port provided in the high-stage compression unit and the lift amount of the reed valve, Since the stage compression unit has a larger volume flow rate of the refrigerant, loss occurs in the low stage compression unit.
Therefore, in the rotary type two-stage compressor, the opening area of the discharge port provided in the low-stage compression unit and the lift amount of the reed valve, the opening area of the discharge port provided in the high-stage compression unit, and the lift of the reed valve It is necessary to set the ratio with the quantity appropriately. By setting this ratio appropriately, the efficiency of the compressor can be improved.

  In Patent Document 1, the ratio S2 / S1 between the area S1 of the discharge port of the low-stage compression unit and the area S2 of the discharge port of the high-stage compression unit is set as the displacement V1 of the low-stage compression unit and the displacement of the high-stage compression unit. There is a description that the ratio is set to 0.55 to 0.85 times the ratio V2 / V1 to the amount V2.

  In Patent Document 2, when the lift amount H1 of the reed valve provided at the discharge port of the low-stage compression unit and the lift amount H2 of the reed valve provided at the discharge port of the high-stage compression unit are set as H1> H2. Is described.

JP 2003-29397 A JP 2008-291650 A

Patent Literature 1 and Patent Literature 2 describe only one setting of the discharge port area and the reed valve lift amount in the low-stage compression section and the high-stage compression section. However, even if only one of the area of the discharge port and the lift amount of the reed valve is set appropriately, the efficiency of the compressor cannot be improved unless the other is set appropriately.
The present invention improves the efficiency of the compressor by appropriately setting the discharge port area and the reed valve lift amount in the low-stage compression unit, and the discharge port area and reed valve lift amount in the high-stage compression unit. The purpose is to improve.

The two-stage compressor according to the present invention is
A low-stage compression section that sucks the refrigerant into the low-stage compression chamber, compresses the drawn refrigerant, and discharges the refrigerant from the low-stage discharge port;
A low-stage discharge section that forms a low-stage discharge space in which the refrigerant compressed by the low-stage compression section is discharged from the low-stage discharge port;
A high stage that sucks the refrigerant discharged into the low-stage discharge space formed by the low-stage discharge part into the high-stage compression chamber via the intermediate connection flow path, compresses the sucked refrigerant, and discharges it from the high-stage discharge port. A compression section;
A high-stage discharge section that forms a high-stage discharge space in which the refrigerant compressed by the high-stage compression section is discharged from the high-stage discharge port;
When the pressure of the refrigerant in the low-stage compression chamber is higher than the pressure of the refrigerant in the low-stage discharge space, provided at the low-stage discharge port of the low-stage compression section, the opening of the low-stage discharge port is opened. A low-stage discharge valve that bends and opens from the closed state toward the low-stage discharge space,
When the pressure of the refrigerant in the high stage compression chamber is higher than the pressure of the refrigerant in the high stage discharge space, the opening of the high stage discharge port is provided at the high stage discharge port of the high stage compression unit. A high-stage discharge valve that opens and bends from the closed state to the high-stage discharge space side;
The opening area of the low-stage outlet is larger than the opening area of the high-stage outlet, and is 2.25 times or less the opening area of the high-stage outlet.
The lift amount of the low stage discharge valve, which is the distance in the direction in which the low stage discharge valve bends between the position of the center of gravity of the low stage discharge port and the low stage discharge valve when the low stage discharge valve is bent open Is the distance in the direction of deflection of the high-stage discharge valve between the position of the center of gravity of the high-stage discharge port and the high-stage discharge valve when the high-stage discharge valve is bent open. The lift amount is 0.47 times to 2.1 times the lift amount.

  In the two-stage compressor according to the present invention, the area of the discharge port and the lift amount of the reed valve in the low-stage compression unit, and the area of the discharge port and the reed valve in the high-stage compression unit are appropriately set. Thereby, the efficiency of a compressor can be improved.

1 is a plan view of a two-stage compressor 100 according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view taken along line A-A ′ in FIG. 1. FIG. 3 is an enlarged view of the compression mechanism unit 3 and the periphery of the compression mechanism unit 3 in FIG. 2. B-B 'sectional drawing in FIG. C-C 'sectional drawing in FIG. D-D 'sectional drawing in FIG. The figure which shows the low stage discharge port 16 vicinity in the state which the low stage discharge valve 17 opened. The figure which shows the low stage discharge port 16 vicinity in the state which the low stage discharge valve 17 closed. The figure which shows the high stage discharge port 36 vicinity in the state which the high stage discharge valve 37 opened. The figure which shows the high stage discharge port 36 vicinity in the state which the high stage discharge valve 37 closed. The figure which shows the relationship between the opening area and lift amount in the case of rotation speed 30rps, and a COP change rate. The figure which shows the relationship between the opening area and lift amount in the case of rotation speed 60rps, and a COP change rate. The figure which shows the relationship between the opening area and lift amount in the case of rotation speed 90rps, and a COP change rate. The figure which shows an evaluation result. The figure which shows the change rate of COP when ratio S1 / S2 and ratio H1 / H2 are set to the optimal value. The figure which shows an example of the circuit structure of the heat pump apparatus which has an injection circuit. The Mollier diagram about the state of the refrigerant | coolant of the heat pump apparatus 101 shown in FIG.

Embodiment 1 FIG.
In the first embodiment, a two-stage compressor 100 having a bypass port that bypasses the high-stage compression unit will be described.

FIG. 1 is a plan view of a two-stage compressor 100 according to the first embodiment.
FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. In FIG. 2, the aa ′ cross section is shown for the intermediate connecting pipe 51 portion.
FIG. 3 is an enlarged view of the compression mechanism unit 3 and the periphery of the compression mechanism unit 3 in FIG. 2.
4 is a cross-sectional view taken along the line BB ′ in FIG.
5 is a cross-sectional view taken along the line CC ′ in FIG.
6 is a cross-sectional view taken along the line DD ′ in FIG.

First, the configuration of the two-stage compressor 100 will be described.
As shown in FIG. 2, the two-stage compressor 100 includes an electric motor 2, a compression mechanism unit 3 including two compression units, a low-stage compression unit 10 and a high-stage compression unit 30, inside the hermetic container 1, A crankshaft 4. A discharge pipe 5 is inserted into the upper part of the sealed container 1. Furthermore, the lower part of the airtight container 1 forms the lubricating oil storage part 6, and lubricating oil is enclosed.
The two-stage compressor 100 includes a suction muffler 7 outside the sealed container 1. The suction muffler 7 is connected to the lower stage compression unit 10 of the compression mechanism unit 3 in the hermetic container 1 by a suction pipe 8.

As shown in FIG. 3, the low-stage compression unit 10 of the compression mechanism unit 3 closes the low-stage cylinder 11, the low-stage frame 14 that closes the upper side of the low-stage cylinder 11, and the lower side of the low-stage cylinder 11. A low-stage compression chamber 15 is formed by the intermediate partition plate 50. A low-stage rolling piston 12 is provided in the low-stage compression chamber 15. A suction pipe 8 is connected to the low stage suction port 21 of the low stage compression chamber 15.
Similarly, the high stage compression unit 30 includes a high stage cylinder 31, a high stage frame 34 that closes the lower side of the high stage cylinder 31, and an intermediate partition plate 50 that closes the upper side of the high stage cylinder 31. A high-stage compression chamber 35 having a smaller volume than the compression chamber 15 is formed. A high-stage rolling piston 32 is provided in the high-stage compression chamber 35.
That is, the two-stage compressor 100 is a rotary two-stage compressor.

  Further, the compression mechanism unit 3 forms a high-stage discharge space 40 between the low-stage cover 19 (low-stage discharge part) that forms the low-stage discharge space 20 between the low-stage frame 14 and the high-stage frame 34. A high-stage cover 39 (high-stage discharge part) to be formed is provided. Further, an intermediate connecting pipe 51 that connects the intermediate outlet 22 of the low stage cover 19 and the high stage suction port 41 of the high stage cylinder 31 is provided, and the low stage discharge space 20 and the high stage compression chamber 35 communicate with each other. Yes.

A low-stage discharge port 16 that connects the low-stage compression chamber 15 and the low-stage discharge space 20 is formed in the low-stage frame 14. The low-stage discharge port 16 is provided with a reed valve in which a low-stage discharge valve 17 and a low-stage valve presser 18 are attached by rivets 28 (see FIG. 5). Similarly, a high-stage discharge port 36 that connects the high-stage compression chamber 35 and the high-stage discharge space 40 is formed in the high-stage frame 34. The high stage discharge port 36 is provided with a reed valve to which a high stage discharge valve 37 and a high stage valve presser 38 are attached by a rivet 48 (see FIG. 6).
Further, the low-stage cover 19 is provided with a bypass port 23 that communicates the low-stage discharge space 20 and the discharge pressure space 53 that is the internal space of the sealed container 1. The bypass port 23 is provided with a reed valve in which a bypass valve 24 and a bypass valve presser 25 are attached by rivets.

  The high stage frame 34, the high stage cylinder 31, the intermediate partition plate 50, the low stage cylinder 11, the low stage frame 14, and the low stage cover 19 are penetrated, and the high stage discharge space 40 and the discharge pressure space are passed through. A discharge passage 52 that communicates with 53 is provided.

  Further, as shown in FIG. 4, the low-stage cover 19 is provided with an injector 60. An injection pipe 61 is connected to the injector 60.

Next, the operation of the two-stage compressor 100 will be described.
When electric power is supplied, the electric motor 2 operates. The electric motor 2 and the compression mechanism unit 3 are connected by a crankshaft 4, and power generated by the electric motor 2 is transmitted to the compression mechanism unit 3 through the crankshaft 4. Then, the crankshaft 4 causes the low stage rolling piston 12 and the high stage rolling piston 32 to rotate eccentrically inside the low stage compression chamber 15 and the high stage compression chamber 35, respectively. As the low stage rolling piston 12 and the high stage rolling piston 32 rotate eccentrically, the low stage compression unit 10 and the high stage compression unit 30 compress the refrigerant.

Next, the refrigerant flow in the two-stage compressor 100 will be described.
First, a low-pressure refrigerant flows into the suction muffler 7 from the outside. The low-pressure refrigerant flowing into the suction muffler 7 is sucked into the low-stage compression chamber 15 through the suction pipe 8. The low-pressure refrigerant sucked into the low stage compression chamber 15 is compressed to an intermediate pressure in the low stage compression chamber 15. When the refrigerant is compressed to an intermediate pressure, the low-stage discharge valve 17 is bent and opened to the low-stage discharge space 20 side due to the pressure difference between the refrigerant in the low-stage compression chamber 15 and the refrigerant in the low-stage discharge space 20. The refrigerant in the stage compression chamber 15 is discharged from the low stage discharge port 16 to the low stage discharge space 20. Here, the intermediate pressure is a pressure determined from the ratio between the volume of the suction chamber of the low-stage compression chamber 15 and the volume of the suction chamber of the high-stage compression chamber 35.
The intermediate pressure refrigerant discharged to the low stage discharge space 20 is sucked into the high stage compression chamber 35 through the intermediate connecting pipe 51. The intermediate-pressure refrigerant sucked into the high-stage compression chamber 35 is compressed to the discharge pressure in the high-stage compression chamber 35. When the refrigerant is compressed to the discharge pressure, the high stage discharge valve 37 bends and opens to the high stage discharge space 40 due to the pressure difference between the refrigerant in the high stage compression chamber 35 and the refrigerant in the high stage discharge space 40. The refrigerant in the stage compression chamber 35 is discharged from the high stage discharge port 36 to the high stage discharge space 40.
The refrigerant having the discharge pressure discharged to the high stage discharge space 40 is discharged to the discharge pressure space 53 above the low stage compression unit 10 via the discharge flow path 52. The refrigerant having the discharge pressure discharged into the discharge pressure space 53 is discharged from the discharge pipe 5 to the outside.
In addition, when the injection operation is performed in the heat pump apparatus including the two-stage compressor 100, the injection refrigerant is injected into the low-stage discharge space 20 from the injection pipe 61 illustrated in FIG. The injection refrigerant is mixed with the intermediate-pressure refrigerant discharged from the low-stage compression chamber 15 in the low-stage discharge space 20 and compressed by the high-stage compression unit 30.

When the load of the heat pump device 101 is small, an overcompressed state that becomes a discharge pressure may occur only by the compression by the low-stage compression unit 10. That is, the intermediate pressure of the refrigerant described above may be higher than the required discharge pressure.
In this case, the bypass valve 24 is opened by the pressure difference between the refrigerant in the low-stage discharge space 20 and the refrigerant in the discharge pressure space 53, and the refrigerant in the low-stage discharge space 20 is discharged from the bypass port 23 to the discharge pressure space 53. . That is, the refrigerant discharged from the low stage compression unit 10 to the low stage discharge space 20 is bypassed and discharged to the discharge pressure space 53 without being compressed by the high stage compression unit 30.
In the overcompressed state, only the compression by the low-stage compression unit 10 results in the discharge pressure. Therefore, the compression by the high-stage compression unit 30 is useless, and if the high-stage compression unit 30 performs compression, the efficiency deteriorates. However, in the two-stage compressor 100, the refrigerant compressed by the low-stage compression unit 10 is discharged by bypassing the high-stage compression unit 30 when the over-compression state occurs. Therefore, loss (overcompression loss) when an overcompressed state occurs can be suppressed.

The reed valve provided in the low stage discharge port 16 and the low stage discharge port 16 and the reed valve provided in the high stage discharge port 36 and the high stage discharge port 36 will be described.
FIG. 7 is a view showing the vicinity of the low-stage discharge port 16 in a state where the low-stage discharge valve 17 is open. FIG. 8 is a view showing the vicinity of the low stage discharge port 16 in a state where the low stage discharge valve 17 is closed.
FIG. 9 is a view showing the vicinity of the high stage discharge port 36 in a state where the high stage discharge valve 37 is open. FIG. 10 is a view showing the vicinity of the high stage discharge port 36 in a state where the high stage discharge valve 37 is closed.

As shown in FIGS. 7 and 8, one end of the low stage discharge valve 17 and the low stage valve presser 18 is fixed to the low stage frame 14 by a rivet 28. The low-stage discharge valve 17 and the low-stage valve presser 18 are provided so that the other end covers the low-stage discharge space 20 side of the low-stage discharge port 16.
The low stage valve presser 18 is fixed in advance to the low stage discharge space 20 side with a predetermined amount of deflection. On the other hand, as described above, the low stage discharge valve 17 bends and opens and closes the low stage discharge port 16 due to the pressure difference between the refrigerant in the low stage compression chamber 15 and the refrigerant in the low stage discharge space 20. The lift amount, which is the size that the low stage discharge valve 17 bends, is limited by the low stage valve presser 18. That is, the lift amount of the low stage discharge valve 17 is set by the low stage valve presser 18.
Here, the lift amount of the low stage discharge valve 17 determined by the low stage valve presser 18 is H1. Moreover, the low stage discharge port 16 is circular, and the radius is D1. That is, the opening area of the low stage discharge port 16 is D1 ² × π (= S1).
The lift amount of the low-stage discharge valve 17 is a distance between the center of the low-stage discharge port 16 and the low-stage discharge valve 17 in a state where the low-stage discharge valve 17 is bent and opened. This is the distance in the rotational axis direction of the shaft 4 that is the direction in which the valve 17 bends (see FIG. 7). That is, the lift amount of the low-stage discharge valve 17 is the length of the center line of the low-stage discharge port 16 between the low-stage discharge valve 17 and the low-stage valve presser 18 when the low-stage discharge valve 17 is closed. (See FIG. 8).
The lift amount of the low stage discharge valve 17 is the distance between the center of gravity of the low stage discharge port 16 and the low stage discharge valve 17 when the low stage discharge port 16 is not circular.

As shown in FIGS. 9 and 10, one end of the high stage discharge valve 37 and the high stage valve presser 38 is fixed to the high stage frame 34 by a rivet 48. The high stage discharge valve 37 and the high stage valve presser 38 are provided so that the other end side covers the high stage discharge space 40 side of the high stage discharge port 36.
The high stage valve presser 38 is fixed in advance by a predetermined amount to the high stage discharge space 40 side. On the other hand, the high stage discharge valve 37 bends and opens and closes the high stage discharge port 36 due to the pressure difference between the refrigerant in the high stage compression chamber 35 and the refrigerant in the high stage discharge space 40 as described above. The lift amount, which is the size that the high stage discharge valve 37 bends, is limited by the high stage valve presser 38. That is, the lift amount of the high stage discharge valve 37 is set by the high stage valve presser 38.
Here, the lift amount of the high stage discharge valve 37 determined by the high stage valve presser 38 is H2. Moreover, the high stage discharge port 36 is circular, and the radius is D2. That is, the opening area of the high stage discharge port 36 is D2 ² × π (= S2).
The lift amount of the high-stage discharge valve 37 is a distance between the center of the high-stage discharge port 36 and the high-stage discharge valve 37 when the high-stage discharge valve 37 is bent and opened. This is the distance in the rotational axis direction of the shaft 4 that is the direction in which the valve 37 bends (see FIG. 9). That is, the lift amount of the high stage discharge valve 37 is the length of the center line of the high stage discharge port 36 between the high stage discharge valve 37 and the high stage valve presser 38 in a state where the high stage discharge valve 37 is closed. (See FIG. 10).
The lift amount of the high stage discharge valve 37 is a distance between the center of gravity of the high stage discharge port 36 and the high stage discharge valve 37 when the high stage discharge port 36 is not circular.

11 to 13 show the opening area of the low stage discharge port 16 and the high stage discharge port 36, the lift amount of the low stage discharge valve 17 and the high stage discharge valve 37, and the COP (Coefficient Of Performance) of the compressor. ) It is a diagram showing the relationship with the rate of change.
Specifically, FIG. 11 to FIG. 13 show the ratio when the ratio H1 / H2 between the lift amount H1 of the low stage discharge valve 17 and the lift amount H2 of the high stage discharge valve 37 is 1 (H1 = H2). COP change when the ratio S1 / S2 between the opening area S1 of the low stage discharge port 16 and the opening area S2 of the high stage discharge port 36 is changed when H1 / H2 is 2 (H1 = 2 × H2). Represents a rate. In particular, FIGS. 11 to 13 show cases where the rotational speed of the two-stage compressor 100 is 30 rps, 60 rps, and 90 rps, respectively.
In FIGS. 11 to 13, each plot represents an evaluation point, and each line is obtained from each evaluation point by the least square method. Further, the change rate of the COP indicates a change rate when the COP when the ratio H1 / H2 is 1 and the ratio S1 / S2 is 1 is defined as a reference value (100%).
Here, a case where the injection operation of injecting the refrigerant from the injection pipe 61 is not performed is shown.

As can be seen from FIG. 11 to FIG. 13, except for the case where the number of rotations of the two-stage compressor 100 is small, if the lift amount ratio H1 / H2 is 1, how much the discharge port opening area ratio S1 / S2 is changed. Even if it does, COP cannot be improved largely from a reference value. That is, the lift amount H1 of the low-stage discharge valve 17 and the lift amount H2 of the high-stage discharge valve 37 are the same, and the opening area S1 of the low-stage discharge port 16 is larger than the opening area S2 of the high-stage discharge port 36. Even so, the COP cannot be greatly improved from the reference value.
This is because if the opening area S1 of the low-stage discharge port 16 is increased, the refrigerant in the low-stage compression unit 10 is easily discharged and the loss is reduced, but on the other hand, it accumulates in the low-stage discharge port 16 and is recompressed. This is because the amount of refrigerant increases and loss increases.
On the other hand, when the ratio S1 / S2 of the opening area of the discharge port is 1, no matter how much the lift ratio H1 / H2 is changed, the COP cannot be improved more than the reference value. That is, the opening area S1 of the low stage discharge port 16 and the opening area S2 of the high stage discharge port 36 are made the same, and the lift amount H1 of the low stage discharge valve 17 is larger than the lift amount H2 of the high stage discharge valve 37. Even so, the COP cannot be greatly improved from the reference value.
This is because if the lift amount H1 of the low-stage discharge valve 17 is increased, the refrigerant in the low-stage compression unit 10 is easily discharged and the loss is reduced. On the other hand, if the lift amount H1 of the low-stage discharge valve 17 is large, This is because the closing of the low-stage discharge valve 17 is delayed, the amount of refrigerant that is re-inhaled and re-compressed increases, and the loss increases.
That is, it is necessary to set the lift ratio H1 / H2 and the opening area ratio S1 / S2 in a well-balanced manner.

Here, as can be seen from FIGS. 11 to 13, when the lift amount ratio H1 / H2 is 2, the lift amount ratio S1 / S2 is generally in the range where the ratio S1 / S2 of the discharge opening is 2 or less. The COP is higher than when the ratio H1 / H2 is 1. In particular, when the rotation speed of the two-stage compressor 100 is 60 rps or 90 rps, the COP is higher when the ratio H1 / H2 is 2 than when the ratio H1 / H2 is 1.
Further, when the ratio H1 / H2 is 2, when the ratio S1 / S2 is an intermediate value between 1 and 1.5 (about 1.2 to 1.3), the COP is the highest.

As a result of repeating such evaluation, the evaluation result shown in FIG. 14 was obtained.
As shown in FIG. 14, the COP is higher than the reference value when the ratio S1 / S2 is greater than 1 and less than or equal to 2.25, and the ratio H1 / H2 is greater than 1 and less than or equal to 2.1. . Further, the COP was higher when the ratio S1 / S2 was greater than 1 and 1.8 or less, and the ratio H1 / H2 was 1.5 or more and 2.1 or less. Furthermore, the COP was higher when the ratio S1 / S2 was greater than 1 and 1.3 or less, and the ratio H1 / H2 was 1.9 or more and 2.1 or less. In particular, when the ratio S1 / S2 was 1.235 and the ratio H1 / H2 was 2.074, the COP was the optimum value that was the highest.

FIG. 15 is a diagram showing the change rate of COP when the ratio S1 / S2 and the ratio H1 / H2 are set to the optimum values of 1.235 and 2.074. In FIG. 15, the change rate of COP indicates the change rate when the ratio H1 / H2 is 1 and the ratio S1 / S2 is 1, and the COP is the reference value (100%).
As shown in FIG. 15, when the ratio S1 / S2 and the ratio H1 / H2 are optimum values, the COP becomes higher than the reference value as the rotational speed of the two-stage compressor 100 increases. Therefore, it can be said that the two-stage compressor 100 is particularly efficient when the load is large and the two-stage compressor 100 must be rotated at a high speed.

Further, when performing the injection operation, the COP increases when the ratio H1 / H2 is set to 0.47 or more and less than 1 while the ratio S1 / S2 is set to the above value. This is because when the refrigerant is injected from the injection pipe 61, the volume flow rate on the high stage compression unit 30 side may be larger than the volume flow rate on the low stage compression unit 10 side. This is because it is necessary to increase the discharge amount.
Note that, in the case of a compressor capable of injection operation, such as the two-stage compressor 100, the ratio H1 / H2 is set so as to improve the efficiency when either the injection operation is performed or when the injection operation is not performed. This may be determined depending on how much the two-stage compressor 100 performs the injection operation. Of course, the amount of deflection of the low-stage valve presser 18 and the high-stage valve presser 38 may be made controllable so that the lift amounts H1 and H2 can be changed according to whether or not the injection operation is performed.

Next, the heat pump apparatus 101 including the two-stage compressor 100 will be described.
FIG. 16 is a diagram illustrating an example of a circuit configuration of a heat pump apparatus having an injection circuit. FIG. 17 is a Mollier diagram of the refrigerant state of the heat pump apparatus 101 shown in FIG. In FIG. 17, the horizontal axis represents specific enthalpy and the vertical axis represents refrigerant pressure.

  The heat pump device 101 includes a main refrigerant circuit in which a two-stage compressor 100, a heat exchanger 71, a first expansion valve 72, a receiver 78, a third expansion valve 74, and a heat exchanger 76 are sequentially connected by piping. In addition, the heat pump apparatus 101 connects an injection circuit including a second expansion valve 75 in the middle of the pipe by connecting the pipe between the receiver 78 and the third expansion valve 74 to the injection pipe 61 of the two-stage compressor 100. Prepare. The heat pump device 101 includes an internal heat exchanger 73 that exchanges heat between the refrigerant in the main refrigerant circuit and the refrigerant in the injection circuit. Furthermore, the heat pump device 101 includes a four-way valve 77 that changes the direction in which the refrigerant flows.

First, the operation | movement at the time of the heating operation of the heat pump apparatus 101 is demonstrated. During the heating operation, the four-way valve 77 is set in the solid line direction. The heating operation includes not only heating used for air conditioning, but also hot water supply that heats water to make hot water.
The gas-phase refrigerant (point 1 in FIG. 17) that has become high-temperature and high-pressure in the two-stage compressor 100 is discharged from the discharge pipe 5 of the two-stage compressor 100 and is heated by the heat exchanger 71 that is a condenser and a radiator. It is exchanged and liquefied (point 2 in FIG. 17). At this time, air or water is warmed by heat radiated from the refrigerant, and heating or hot water is supplied.
The liquid-phase refrigerant liquefied by the heat exchanger 71 is depressurized by the first expansion valve 72 (decompression mechanism) and becomes a gas-liquid two-phase state (point 3 in FIG. 17). The refrigerant in the gas-liquid two-phase state by the first expansion valve 72 is heat-exchanged with the refrigerant sucked into the two-stage compressor 100 by the receiver 78, cooled and liquefied (point 4 in FIG. 17). The liquid-phase refrigerant liquefied by the receiver 78 branches and flows into the internal heat exchanger 73, the main refrigerant circuit on the third expansion valve 74 side, and the injection circuit on the second expansion valve 75 side.
The liquid-phase refrigerant flowing through the main refrigerant circuit is heat-exchanged by the internal heat exchanger 73 with the refrigerant flowing through the injection circuit that has been decompressed by the second expansion valve 75 and is in a gas-liquid two-phase state, and is further cooled (FIG. 17). Point 5). The liquid-phase refrigerant cooled by the internal heat exchanger 73 is decompressed by the third expansion valve 74 (decompression mechanism) and becomes a gas-liquid two-phase state (point 6 in FIG. 17). The refrigerant in the gas-liquid two-phase state by the third expansion valve 74 is heat-exchanged and heated by the heat exchanger 76 serving as an evaporator (point 7 in FIG. 17). Then, the refrigerant heated by the heat exchanger 76 is further heated by the receiver 78 (point 8 in FIG. 17), and is sucked into the two-stage compressor 100 from the suction pipe 8.
On the other hand, as described above, the refrigerant flowing through the injection circuit is decompressed by the second expansion valve 75 (decompression mechanism) (point 9 in FIG. 17) and is heat-exchanged by the internal heat exchanger 73 (point in FIG. 17). 10). The gas-liquid two-phase refrigerant (injection refrigerant) heat-exchanged by the internal heat exchanger 73 flows into the low-stage discharge space 20 from the injection pipe 61 of the two-stage compressor 100 in the gas-liquid two-phase state.
In the two-stage compressor 100, the refrigerant (point 8 in FIG. 17) flowing through the main refrigerant circuit and sucked from the suction pipe 8 is compressed and heated to an intermediate pressure by the low-stage compressor 10 (point 11 in FIG. 17). ). The refrigerant (point 11 in FIG. 17) discharged into the low-stage discharge space 20 compressed and heated to the intermediate pressure and the injection refrigerant (point 8 in FIG. 17) merge to lower the temperature (in FIG. 17). Point 12). And the refrigerant | coolant (point 12 of FIG. 17) in which temperature fell is further compressed and heated by the high stage compression part 30, becomes high temperature high pressure, and is discharged to the discharge pressure space 53 from the discharge flow path 52 (point 1 of FIG. 17). ).

When the injection operation is not performed, the opening of the second expansion valve 75 is fully closed. That is, when the injection operation is performed, the opening degree of the second expansion valve 75 is larger than the predetermined opening degree. However, when the injection operation is not performed, the opening degree of the second expansion valve 75 is predetermined. The opening is smaller than. Thereby, the refrigerant does not flow into the injection pipe 61 of the two-stage compressor 100. That is, all the refrigerant that has passed through the heat exchanger 71, the first expansion valve 72, and the receiver 78 is sucked into the two-stage compressor 100 from the suction pipe 8.
Here, the opening degree of the second expansion valve 75 is controlled by electronic control by the control unit. The control unit is, for example, a microcomputer.

Next, the operation | movement at the time of the cooling operation of the heat pump apparatus 101 is demonstrated. During the cooling operation, the four-way valve 77 is set in a broken line direction.
The gas-phase refrigerant (point 1 in FIG. 17) that has become high temperature and high pressure in the two-stage compressor 100 is discharged from the discharge pipe 5 of the two-stage compressor 100 and is heated by the heat exchanger 76 that is a condenser and a radiator. It is exchanged and liquefied (point 2 in FIG. 17). The liquid phase refrigerant liquefied by the heat exchanger 76 is depressurized by the third expansion valve 74 and becomes a gas-liquid two-phase state (point 3 in FIG. 17). The refrigerant in the gas-liquid two-phase state by the third expansion valve 74 is heat-exchanged by the internal heat exchanger 73, cooled and liquefied (point 4 in FIG. 17). In the internal heat exchanger 73, the refrigerant that has become a gas-liquid two-phase state by the third expansion valve 74 and the liquid-phase refrigerant that has been liquefied by the internal heat exchanger 73 are decompressed by the second expansion valve 75, and the gas-liquid two-phase Heat is exchanged with the refrigerant in the state (point 9 in FIG. 17). The liquid refrigerant (point 4 in FIG. 17) heat-exchanged by the internal heat exchanger 73 branches and flows into the main refrigerant circuit on the receiver 78 side and the injection circuit on the internal heat exchanger 73 side.
The liquid-phase refrigerant flowing through the main refrigerant circuit is heat-exchanged with the refrigerant sucked into the two-stage compressor 100 by the receiver 78 and further cooled (point 5 in FIG. 17). The liquid-phase refrigerant cooled by the receiver 78 is decompressed by the first expansion valve 72 and becomes a gas-liquid two-phase state (point 6 in FIG. 17). The refrigerant in the gas-liquid two-phase state by the first expansion valve 72 is heat-exchanged and heated by the heat exchanger 71 serving as an evaporator (point 7 in FIG. 17). At this time, the refrigerant absorbs heat, thereby cooling the air, water, etc., cooling, making cold water or ice, or freezing.
The refrigerant heated by the heat exchanger 71 is further heated by the receiver 78 (point 8 in FIG. 17), and is sucked into the two-stage compressor 100 from the suction pipe 8.
On the other hand, as described above, the refrigerant flowing through the injection circuit is decompressed by the second expansion valve 75 (point 9 in FIG. 17) and heat-exchanged by the internal heat exchanger 73 (point 10 in FIG. 17). The gas-liquid two-phase refrigerant (injection refrigerant) heat-exchanged by the internal heat exchanger 73 flows into the low-stage discharge space 20 from the injection pipe 61 of the two-stage compressor 100 in the gas-liquid two-phase state.
The compression operation in the two-stage compressor 100 is the same as in the heating operation.

  When the injection operation is not performed, the opening of the second expansion valve 75 is fully closed so that the refrigerant does not flow into the injection pipe 61 of the two-stage compressor 100 as in the heating operation.

  Further, as described above, the heat exchanger 71 may be a heat exchanger that performs heat exchange between a gas phase refrigerant that has become high temperature and pressure or a liquid phase refrigerant that has become low temperature and low pressure and a liquid such as water. Moreover, the heat exchanger 71 may be a heat exchanger that performs heat exchange between a gas-phase refrigerant that has become high temperature and pressure or a liquid-phase refrigerant that has become low temperature and low pressure and a gas such as air. That is, the heat pump apparatus 101 described in FIG. 16 may be an air conditioner, a hot water supply apparatus, a refrigeration apparatus, or a refrigeration apparatus.

Here, the injection operation is performed when the load is high. The load is a necessary load that is an amount of heat necessary to bring the temperature of the fluid that exchanges heat with the refrigerant flowing through the main refrigerant circuit in the heat exchanger 71 to a predetermined temperature. The required load can be measured by using the outside air temperature, the rotational speed of the compressor, or the like as an index. Here, it is assumed that a required load detection unit (not shown) detects the required load by detecting the outside air temperature, the rotational speed of the compressor, and the like.
For example, in the case of heating operation, the injection operation is performed when the outside air temperature is equal to or lower than a predetermined temperature (for example, 2 ° C.) or when the rotational speed of the compressor is equal to or higher than a predetermined frequency (for example, 60 Hz). Thereby, the heating capability at the time of low outside temperature can be made high, and the heat pump apparatus with a good heating and hot water supply performance is obtained. In other cases where the injection operation is not necessary, the opening of the second expansion valve 75 is fully closed and the injection operation is not performed even during the heating operation.

  The two-stage compressor 100 is efficient by setting the ratio S1 / S2 and the ratio H1 / H2 as described above. Therefore, the heat pump device including the two-stage compressor 100 is also efficient.

  DESCRIPTION OF SYMBOLS 1 Airtight container, 2 Electric motor, 2a Stator, 2b Rotor, 3 Compression mechanism part, 4 Crankshaft, 5 Discharge pipe, 6 Lubricating oil storage part, 7 Intake muffler, 8 Intake pipe, 10 Low stage compression part, 11 Low Stage cylinder, 12 Low stage rolling piston, 13 Low stage vane, 14 Low stage frame, 15 Low stage compression chamber, 16 Low stage discharge port, 17 Low stage discharge valve, 18 Low stage valve presser, 19 Low stage cover, 20 Low Stage discharge space, 21 Low stage suction port, 22 Intermediate outlet, 23 Bypass port, 24 Bypass valve, 25 Bypass valve presser, 26 Low stage back pressure chamber, 27 Spring, 28, 29 Rivet, 30 High stage compression section, 31 High stage cylinder, 32 High stage rolling piston, 33 High stage vane, 34 High stage frame, 35 High stage compression chamber, 36 High stage discharge port, 37 High stage discharge valve, 38 High stage valve presser, 3 9 High stage cover, 40 High stage discharge space, 41 High stage suction port, 42 High stage suction flow path, 46 High stage back pressure chamber, 49 Rivet, 50 Intermediate partition plate, 51 Intermediate connection pipe, 52 Discharge flow path, 53 Discharge pressure space, 54 four-way valve, 55 pressure introduction path, 60 injector, 61 injection pipe, 71 heat exchanger, 72 first expansion valve, 73 internal heat exchanger, 74 third expansion valve, 75 second expansion valve, 76 Heat exchanger, 77 four-way valve, 78 receiver, 100 two-stage compressor, 101 heat pump device.

Claims (8)

A low-stage compression section that sucks the refrigerant into the low-stage compression chamber, compresses the drawn refrigerant, and discharges the refrigerant from the low-stage discharge port;
A low-stage discharge section that forms a low-stage discharge space in which the refrigerant compressed by the low-stage compression section is discharged from the low-stage discharge port;
A high stage that sucks the refrigerant discharged into the low-stage discharge space formed by the low-stage discharge part into the high-stage compression chamber via the intermediate connection flow path, compresses the sucked refrigerant, and discharges it from the high-stage discharge port. A compression section;
A high-stage discharge section that forms a high-stage discharge space in which the refrigerant compressed by the high-stage compression section is discharged from the high-stage discharge port;
When the pressure of the refrigerant in the low-stage compression chamber is higher than the pressure of the refrigerant in the low-stage discharge space, provided at the low-stage discharge port of the low-stage compression section, the opening of the low-stage discharge port is opened. A low-stage discharge valve that bends and opens from the closed state toward the low-stage discharge space,
When the pressure of the refrigerant in the high stage compression chamber is higher than the pressure of the refrigerant in the high stage discharge space, the opening of the high stage discharge port is provided at the high stage discharge port of the high stage compression unit. A high-stage discharge valve that opens and bends from the closed state to the high-stage discharge space side;
The opening area of the low-stage outlet is larger than the opening area of the high-stage outlet, and is 2.25 times or less the opening area of the high-stage outlet.
The lift amount of the low stage discharge valve, which is the distance in the direction in which the low stage discharge valve bends between the position of the center of gravity of the low stage discharge port and the low stage discharge valve when the low stage discharge valve is bent open Is the distance in the direction of deflection of the high-stage discharge valve between the position of the center of gravity of the high-stage discharge port and the high-stage discharge valve when the high-stage discharge valve is bent open. A two-stage compressor having a lift amount of 0.47 times or more and 2.1 times or less. 2. The two-stage according to claim 1, wherein a lift amount of the low-stage discharge valve is larger than a lift amount of the high-stage discharge valve and is 2.1 times or less of a lift amount of the high-stage discharge valve. Compressor. The opening area of the low stage outlet is 1.8 times or less the opening area of the high stage outlet,
The two-stage compressor according to claim 2, wherein the lift amount of the low-stage discharge valve is 1.5 times or more the lift amount of the high-stage discharge valve. The opening area of the low stage outlet is 1.3 times or less the opening area of the high stage outlet,
The two-stage compressor according to claim 3, wherein a lift amount of the low-stage discharge valve is 1.9 times or more a lift amount of the high-stage discharge valve. The opening area of the low stage outlet is 1.235 times the opening area of the high stage outlet,
5. The two-stage compressor according to claim 4, wherein the lift amount of the low-stage discharge valve is 2.074 times the lift amount of the high-stage discharge valve. The two-stage compressor further includes:
An injection pipe connected to the low-stage discharge part or the intermediate connection flow path and into which refrigerant is injected from the outside,
2. The two-stage according to claim 1, wherein the lift amount of the low-stage discharge valve is smaller than the lift amount of the high-stage discharge valve and is 0.47 times or more the lift amount of the high-stage discharge valve. Compressor. A heat pump device in which a compressor, a radiator, a first expansion mechanism, and an evaporator are sequentially connected by piping;
The compressor is
A low-stage compression section that sucks the refrigerant into the low-stage compression chamber, compresses the drawn refrigerant, and discharges the refrigerant from the low-stage discharge port;
A low-stage discharge section that forms a low-stage discharge space in which the refrigerant compressed by the low-stage compression section is discharged from the low-stage discharge port;
A high stage that sucks the refrigerant discharged into the low-stage discharge space formed by the low-stage discharge part into the high-stage compression chamber via the intermediate connection flow path, compresses the sucked refrigerant, and discharges it from the high-stage discharge port. A compression section;
A high-stage discharge section that forms a high-stage discharge space in which the refrigerant compressed by the high-stage compression section is discharged from the high-stage discharge port;
When the pressure of the refrigerant in the low-stage compression chamber is higher than the pressure of the refrigerant in the low-stage discharge space, provided at the low-stage discharge port of the low-stage compression section, it bends toward the low-stage discharge space. A low-stage discharge valve that opens at
When the pressure of the refrigerant in the high-stage compression chamber is higher than the pressure of the refrigerant in the high-stage discharge space, provided at the high-stage discharge port of the high-stage compression section, it bends toward the low-stage discharge space. With a high-stage discharge valve that opens at
The opening area of the low-stage outlet is larger than the opening area of the high-stage outlet, and is 2.25 times or less the opening area of the high-stage outlet.
A heat pump device characterized in that a lift amount that is a height at which the low-stage discharge valve is bent is 0.47 times or more and 2.1 times or less than a lift amount that is a height at which the high-stage discharge valve is bent. The heat pump device further includes:
An injection circuit provided between the radiator and the first expansion mechanism and an injection pipe connected to the low-stage discharge part of the compressor or the intermediate connection flow path and provided with a second expansion mechanism; With
8. The heat pump device according to claim 7, wherein the lift amount of the low stage discharge valve is smaller than the lift amount of the high stage discharge valve and is 0.47 times or more the lift amount of the high stage discharge valve. .

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