Compressor and compressor system

Abstract

A compressor of one embodiment includes a cylinder (12), a piston (14) configured to be able to reciprocate in the cylinder (12), a suction space (Si) capable of communicating with a working chamber (Sc) formed by the cylinder (12) and the piston (14), a discharge space (Sv) capable of communicating with the working chamber (Sc), a partition wall portion (16) arranged so as to surround the working chamber (Sc) and dividing the suction space (Si) and the discharge space (Sv), and a cooling medium path (18) formed in the partition wall portion (16).

Description

Technical Field

[0001] This invention relates to a compressor and a compressor system. Background Technology

[0002] In reciprocating compressors, there are typically intake and exhaust gas passages within the casing. Therefore, the high-temperature exhaust gas and the low-temperature intake gas exchange heat through the casing walls, potentially causing the intake gas temperature to rise before being drawn into the cylinder. This results in the intake gas expanding before being drawn into the cylinder, increasing its specific volume and reducing the mass flow rate of the exhaust gas to a non-negligible level. Consequently, the volumetric efficiency of the compressor may decrease, leading to a reduction in cooling capacity when the reciprocating compressor is installed in a refrigeration system.

[0003] Therefore, as a way to suppress compressor overheating, for example, piping for flowing cooling water is installed inside the crankcase and end cover. Patent Documents 1 and 2 disclose a structure in which refrigerant liquid is injected into the discharge space inside the end cover, and the latent heat of vaporization of the refrigerant liquid is used to cool the compressed discharge gas, thereby suppressing the overheating of the intake gas.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-53765

[0007] Patent Document 2: Japanese Patent Application Publication No. 2011-163192 Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] According to the structures disclosed in Patent Documents 1 and 2, overheating of the intake gas can be suppressed by cooling the exhaust gas. However, due to the effect of cooling the exhaust gas, a large amount of frost may be generated on the surface of the compressor (e.g., the surface of the end cover or the housing). This structure that generates a large amount of frost is not ideal.

[0010] The present invention addresses the above-mentioned problems and aims to reduce the risk of frost adhering to the surface of the compressor and suppress heat input from the discharge space to the suction space, thereby preventing a decrease in the volumetric efficiency of the compressor caused by heat input from the discharge space to the suction space.

[0011] (II) Technical Solution

[0012] To achieve the above objectives, the compressor of the present invention comprises: a cylinder, a piston configured to reciprocate within the cylinder, an intake space communicatively connected to a working chamber formed by the cylinder and the piston, an exhaust space communicatively connected to the working chamber, a partition wall portion arranged to surround the working chamber and dividing the intake space and the exhaust space, and a cooling medium path formed on the partition wall portion.

[0013] In addition, the compressor system of the present invention includes: the compressor described above, a refrigerant circulation path communicating with the suction space and the discharge space of the compressor, a condenser for condensing the discharge gas discharged from the discharge space, and a branch path that branches off from the refrigerant circulation path and communicates with the cooling medium path on the downstream side of the condenser.

[0014] (III) Beneficial Effects

[0015] According to the compressor of the present invention, a cooling medium is supplied to a cooling medium path formed on a partition wall dividing the suction space and the discharge space. This reduces the risk of frost adhering to the compressor surface and suppresses heat input from the discharge space to the suction space, preventing a decrease in the compressor's volumetric efficiency caused by heat input from the discharge space to the suction space. Furthermore, in addition to the above-described effects, the compressor system of the present invention, when applied to refrigeration systems and heat pump systems, can also suppress a decrease in COP. Attached Figure Description

[0016] Figure 1 This is a front cross-sectional view of a reciprocating compressor according to one embodiment.

[0017] Figure 2 This is a front cross-sectional view of a reciprocating compressor according to one embodiment.

[0018] Figure 3 This is a front cross-sectional view of a reciprocating compressor according to one embodiment.

[0019] Figure 4 This is a system diagram of a compressor system according to one embodiment.

[0020] Figure 5 This is a system diagram of a compressor system according to one embodiment.

[0021] Figure 6 This is a system diagram of a compressor system according to one embodiment.

[0022] Figure 7 This is a system diagram of a compressor system according to one embodiment. Detailed Implementation

[0023] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0024] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configuration do not only indicate configuration in a strict sense, but also indicate a state of relative displacement by angle or distance with tolerance, or to the extent that the same function can be obtained.

[0025] For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state do not only mean that they are strictly equal, but also that there is a difference in the degree to which they can achieve the same function.

[0026] For example, expressions representing shapes such as quadrilaterals and cylinders do not only refer to quadrilaterals and cylinders in a strictly geometric sense, but also include shapes with concave and convex parts, chamfers, etc., within the range that can achieve the same effect.

[0027] On the other hand, expressions that "have," "possess," "have," "include," or "have" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0028] Figures 1-3 These are front cross-sectional views of compressors 10 (10A, 10B, 10C) according to some embodiments. Figures 1-3 In this compressor, 10 (10A-10C) includes a cylinder 12 and a piston 14 configured to reciprocate within the cylinder 12, forming a working chamber Sc. It also includes an intake space Si and an exhaust space Sv that communicate with the working chamber Sc. A partition 16 is provided surrounding the working chamber Sc, dividing the intake space Si and the exhaust space Sv. An intake valve 20 for switching the communication state between the intake space Si and the working chamber Sc, and an exhaust valve 22 for switching the communication state between the exhaust space Sv and the working chamber Sc, are provided on the partition 16, and a cooling medium path 18 for flowing cooling medium is formed therein.

[0029] In the above embodiment, the intake gas drawn into the intake space Si is drawn into the working chamber Sc through a passage opened and closed by the intake valve 20, and compressed by the piston 14. The compressed intake gas, which becomes high temperature and high pressure, is discharged into the discharge space Sv through a passage opened and closed by the discharge valve 22. By flowing the cooling medium in the cooling medium path 18 formed on the partition 16 dividing the intake space Si and the discharge space Sv, heat input from the discharge space Sv to the intake space Si can be suppressed, thus suppressing the reduction in volumetric efficiency of the compressor 10 caused by heat input from the discharge space Sv to the intake space Si. On the other hand, the partition 16 provided inside the compressor 10 is far from the compressor surface, thus suppressing the temperature drop of the compressor surface. Therefore, the formation of frost on the compressor surface can be suppressed.

[0030] about Figures 1-3 The illustrated embodiment constitutes a so-called reciprocating compressor. A crankshaft 24 is provided at the lower part, and the piston 14 is connected to the crankshaft 24 via a connecting rod 26. The piston 14 reciprocates within the cylinder block 12 by the rotation of the crankshaft 24. Regarding... Figures 1-3 The illustrated reciprocating compressor has two cylinders 12 arranged side-by-side relative to a crankshaft 24 and connected to it such that their respective pistons 14 reciprocate with a phase angle differing by 180°. The upper surface of the cylinder 12 is enclosed by a valve cover 28, and an end cap 46 for forming a discharge space Sv is provided above the partition wall 16. An opening 46a for discharging discharge gas is formed on the end cap 46.

[0031] The cooling medium supplied to the cooling medium path 18 may be, for example, cooling water or antifreeze. Furthermore, when the compressor 10 is installed in a refrigeration system or a heat pump system, liquid refrigerant, which is the working fluid of these systems, can be used.

[0032] In one implementation, such as Figure 1 and Figure 2 As shown, the partition 16 includes a valve plate 30 for holding the suction valve 20 and the discharge valve 22, and a cooling medium path 18 is formed in the valve plate 30. By flowing a cooling medium in the cooling medium path 18, the valve plate 30 is cooled, thereby suppressing the heat input from the discharge space Sv to the suction space Si. This suppresses the reduction in the volumetric efficiency of the compressor 10 caused by the heat input from the discharge space Sv to the suction space Si. On the other hand, since the discharge space Sv exists between the valve plate 30 and the compressor surface (e.g., the surface of the end cover 46), the temperature drop of the compressor surface (e.g., the surface of the end cover 46) can be suppressed. Therefore, the formation of frost on the compressor surface can be suppressed.

[0033] In one implementation, such as Figures 1-3 As shown, the compressor 10 (10A~10C) includes a compressor housing 32, which has a built-in suction space Si for housing the cylinder 12 and piston 14. Figure 1 and Figure 2 In the embodiment shown, a first flow path groove 31 with an opening 31a is formed on the valve plate 30 on the side of the compressor housing 32, and the cooling medium path 18 is formed by the first flow path groove 31.

[0034] According to this embodiment, the cooling medium path 18 is formed by the first flow path groove 31, so it is not necessary to form a deep hole on the valve plate 30. The cooling medium path 18 can be formed by machining from the surface of the valve plate 30. Therefore, it is easy to perform the machining for forming the cooling medium path 18 on the valve plate 30. Furthermore, the first flow path groove 31 has an opening 31a on the compressor housing 32 side, so the suction space Si can be cooled using the cooling medium flowing in the cooling medium path 18.

[0035] In one embodiment, the first flow path 31 is formed in a circular shape to surround the cylinder body 12. Figure 1 In the exemplary embodiment shown, the outer periphery of the valve plate 30 protrudes outside the end cover 46. The cooling medium path 18 has a through hole 33 opening at the end face of this periphery, and is equipped with a nozzle 50 for spraying cooling medium into the through hole 33. A supply pipe 52 is connected to supply cooling medium to the nozzle 50. Using the cooling medium sprayed in a mist from the nozzle 50, the valve plate 30 can be cooled uniformly. Furthermore, on the opposite side of the cooling medium supply side of the compressor body, a connecting path 62 is formed on the partition wall of the valve plate 30, communicating with the cooling medium path 18 and the discharge space Sv, through which the cooling medium is discharged into the discharge space Sv.

[0036] exist Figure 2In the exemplary embodiment shown, a supply path 36 for supplying cooling medium to the first flow path groove 31 is formed in the wall of the compressor housing 32, and a supply pipe 38 for supplying cooling medium to the supply path 36 is connected thereto. Thus, by forming the supply path 36 in the wall of the compressor housing 32, a supply path for supplying cooling medium to the first flow path groove 31 is easily formed. Furthermore, a throttling valve 39 is provided at the outlet of the cooling medium supplied from the supply pipe 38 to the supply path 36, which opens into the cooling medium path 18. The cooling medium is atomized by the throttling valve 39 and sprayed into the cooling medium path 18. The throttling valve 39 is, for example, a plug having multiple small-diameter through holes communicating with the supply path 36 and the cooling medium path 18. In another embodiment, the outlet opening diameter of the supply path 36 can be reduced instead of providing a throttling valve 39 to achieve the function of a throttling valve. On the other hand, a discharge path 58 is formed on the compressor housing 32 on the opposite side of the compressor body relative to the supply path 36. The discharge path 58 is used to discharge the cooling medium after cooling from the first flow path 31. A refrigerant discharge path 60 is connected to the outer opening of the discharge path 58.

[0037] exist Figure 2 In the compressor 10 (10B) shown, even when the end cover 46 needs to be removed for maintenance, it is not necessary to remove the supply pipe 38 from the compressor housing 32, thus making maintenance work easy.

[0038] exist Figures 1-3 In the exemplary embodiment shown, the compressor housing 32 also serves as a crankcase, and the crankshaft 24 is housed inside the compressor housing 32.

[0039] In one embodiment, an insulating gasket can be inserted between the stacked portion of the valve plate 30 and the compressor housing 32. However, in this case, if a gasket is placed in the region of the first flow path groove 31, it would hinder the cooling effect of the intake gas flowing in the intake space Si, so it is avoided to place a gasket on the opening 31a.

[0040] In one implementation, such as Figure 3As shown, a second flow path groove 34 is formed on the surface of the compressor housing 32 on the valve plate 30 side, and the cooling medium path 18 is formed by the second flow path groove 34. According to this embodiment, by flowing the cooling medium in the cooling medium path 18, the partition wall portion 16 containing the valve plate 30 can be cooled, thereby suppressing the heat input from the discharge space Sv to the suction space Si. As a result, the reduction in the volumetric efficiency of the compressor 10 caused by the heat input from the discharge space Sv to the suction space Si can be suppressed. On the other hand, even when the cooling medium flows in the cooling medium path 18, the temperature drop of the compressor surface (e.g., the surface of the end cover 46) can be suppressed because there is a discharge space Sv between the valve plate 30 and the compressor surface. Therefore, the formation of frost on the compressor surface can be suppressed. Furthermore, since the cooling medium path 18 can be formed by cutting the surface of the compressor housing 32, it is easy to form the cooling medium path 18.

[0041] In one implementation, such as Figure 3 As shown, in order to supply cooling medium to the second flow path 34, a supply path 36 is formed on the compressor housing 32, and a supply pipe 38 is connected to the outer opening of the supply path 36. On the other hand, a discharge path 40 is formed on the compressor housing 32 on the opposite side of the compressor body relative to the supply path 36. The discharge path 40 is used to discharge the cooled medium after cooling from the second flow path 34, and a refrigerant discharge path 42 is connected to the outer opening of the discharge path 40.

[0042] In one implementation, such as Figure 3 As shown, an insulating gasket 44 is fitted onto the contact surface where the valve plate 30 and the compressor housing 32 abut against each other. The insulating gasket 44 includes, for example, a region where a second flow path groove 34 is formed, and is fitted onto the entire contact surface between the valve plate 30 and the compressor housing 32. By providing the insulating gasket 44, heat input from the discharge space Sv to the suction space Si inside the compressor housing 32 can be effectively suppressed.

[0043] In one implementation, such as Figure 1 and Figure 3 As shown, the outer periphery of the valve plate 30 is sandwiched between the outer periphery of the compressor housing 32 and the outer periphery of the end cover 46. Therefore, by using bolts or other fastening tools to secure the end cover 46, valve plate 30, and the three outer peripheries of the compressor housing 32 together, the valve plate 30 can be easily installed onto the compressor body. Furthermore, in Figure 1 In the embodiment shown, since the end face of the outer periphery of the valve plate 30 is exposed outside the compressor 10, it is easy to install the nozzle 50 in the opening of the through hole 33 that communicates with the cooling medium path 18.

[0044] exist Figure 1 and Figure 3 In the exemplary embodiment shown, the end cap 46, valve plate 30, and outer periphery of compressor housing 32 are fastened together with bolts 48. Regarding Figure 2 The compressor 10 (10B) shown has an outer periphery of end cover 46 and an outer periphery of compressor housing 32 connected by bolts 54, and the outer periphery of valve plate 30 is located inside end cover 46.

[0045] Figure 4 and Figure 5 This is a system diagram illustrating compressor systems 70 (70A, 70B) according to some embodiments. Compressors 10 (10A to 10C) of the above embodiments are installed in the refrigerant circulation path 72 of compressor systems 70 (70A, 70B). Compressor system 70 includes a refrigerant circulation path 72 communicating with the suction space Si and discharge space Sv of compressor 10. The refrigerant circulation path 72 includes: a condenser 74 for condensing refrigerant gas discharged from the discharge space Sv; and a branch path 76 that branches off from the refrigerant circulation path 72 downstream of the condenser 74 and communicates with a cooling medium path 18.

[0046] The compressor system 70 (70A, 70B) constitutes the refrigeration system. Refrigerant gas discharged from the discharge space Sv is cooled and liquefied in the condenser 74. Most of the liquefied refrigerant is depressurized by the expansion valve 79 provided in the refrigerant circulation path 72 and evaporates in the evaporator 80, thus cooling the load medium w. The refrigerant gas vaporized in the evaporator 80 is drawn into the suction chamber 82 of the suction space Si forming the compressor 10. The refrigerant gas drawn into the suction chamber 82 is pressurized in the compressor 10 and discharged through the discharge chamber 84 forming the discharge space Sv into the refrigerant circulation path 72. Downstream of the condenser 74, a branch path 76 is provided, branching from the refrigerant circulation path 72. The branch path 76 communicates with the cooling medium path 18 formed on the partition wall 16 of the compressor 10. A portion of the liquid refrigerant flowing in the refrigerant circulation path 72 is supplied to the cooling medium path 18 via the branch path 76, cooling the partition wall 16.

[0047] exist Figure 4 and Figure 5 In the exemplary embodiment shown, an oil separator 86 and a liquid receiver 88 are provided. The oil separator 86 separates refrigerant oil from the refrigerant gas discharged from the compressor 10, and the liquid receiver 88 temporarily stores the refrigerant liquid condensed in the condenser 74. Furthermore, the compressor 10 is a reciprocating compressor.

[0048] exist Figure 4 A liquid pump 77 is installed on branch path 76 of the compressor system 70 (70A) shown. When the compressor system 70 (70A) adopts... Figure 1 In the compressor 10 (10A) shown, since the branch path 76 and the discharge space Sv have the same pressure, a liquid pump 77 is required to supply refrigerant liquid from the branch path 76 to the cooling medium path 18. The liquid pump 77 pressurizes the refrigerant liquid flowing in the branch path 76, thereby enabling the supply of refrigerant liquid to the cooling medium path 18. If necessary, a pressure regulating valve 78 can be provided downstream of the liquid pump 77 to adjust the pressure of the refrigerant liquid flowing in the branch path 76. For the refrigerant liquid flowing into the cooling medium path 18, which has a lower pressure than the branch path 76, evaporation occurs at low pressure, absorbing heat from the surroundings, thus cooling the partition wall 16.

[0049] Therefore, heat input from the discharge space Sv to the suction space Si can be suppressed, and the reduction in volumetric efficiency of the compressor 10 caused by this heat input can be suppressed. Furthermore, when the compressor 10 is applied to a refrigeration system or heat pump system, such as compressor systems 70 (70A, 70B), the reduction in the COP of these systems can be suppressed. Additionally, since the discharge space Sv exists between the partition wall 16 and the compressor surface (e.g., the surface of the end cover 46), and the partition wall 16 is far from the compressor surface, the temperature drop of the compressor surface (e.g., the surface of the end cover 46) can be suppressed. Therefore, the formation of frost on the compressor surface can be suppressed.

[0050] Figure 4 The compressor system 70 (70A) shown includes a liquid pump 77, therefore, when used as compressor 10 Figure 2 The compressor 10 (10B) shown or Figure 3 When the compressor 10 (10C) is shown, by appropriately setting the pressure generated by the liquid pump 77, the refrigerant discharge path 42 or 60 can be connected to any position in the refrigerant circulation path 72. Preferably, the refrigerant discharge path 42 or 60 is connected to the refrigerant circulation path 72 upstream of the condenser 74 (e.g., the refrigerant circulation path 72 between the oil separator 86 and the condenser 74), so that the refrigerant used in the cooling partition 16 does not have to return to the refrigerant circulation path 72 downstream of the expansion valve 79. Therefore, supplying refrigerant to the cooling medium path 18 does not reduce the capacity of the compressor 10. Furthermore, since it is an injection from high-pressure liquid, the refrigerant dosage is small, so the effect of the power increase caused by the liquid pump is small.

[0051] Figure 5 The compressor system 70 (70B) shown is used as compressor 10. Figure 2 or Figure 3The embodiment shown is for compressor 10 (10B, 10C). In this embodiment, instead of a liquid pump 77 on branch path 76, refrigerant discharge path 42 or 60 is connected to the refrigerant circulation path 72 between expansion valve 79 and compressor 10 (10B, 10C). For the refrigerant circulation path 72 in this area, since the pressure of branch path 76 is low, even without a liquid pump 77 on branch path 76, the refrigerant liquid supplied from branch path 76 to cooling medium path 18 can be discharged to the refrigerant circulation path 72 in this area via refrigerant discharge path 42 or 60. Furthermore, by controlling complete vaporization in the cooling medium path, liquid backflow can be prevented.

[0052] Figure 6 and Figure 7 The compressor system 70 (70C, 70D) shown includes a low-stage compressor 10a and a high-stage compressor 10b arranged in series in a refrigerant circulation path 72. Refrigerant gas discharged from the discharge chamber 84 of the low-stage compressor 10a is supplied to the suction chamber 82 of the high-stage compressor 10b via the refrigerant circulation path 72 (intermediate path 72(72a)) provided between the low-stage compressor 10a and the high-stage compressor 10b. The refrigerant gas supplied to the suction chamber 82 of the high-stage compressor 10b is further compressed and discharged from the discharge chamber 84 into the refrigerant circulation path 72.

[0053] Figure 6 and Figure 7 The compressor system 70 (70C, 70D) shown constitutes a refrigeration system. The refrigerant, depressurized by the expansion valve 79, evaporates in the evaporator 80 and is cooled by removing latent heat of vaporization from the load medium w. Figure 6 and Figure 7 In the exemplary embodiment shown, two oil separators 86 and a liquid receiver 88 are provided. The oil separators 86 separate refrigerant oil from the refrigerant gas discharged from the compressors 10 (low-stage compressor 10a and high-stage compressor 10b), and the liquid receiver 88 temporarily stores the refrigerant liquid condensed in the condenser 74. Furthermore, the low-stage compressor 10a and the high-stage compressor 10b are reciprocating compressors.

[0054] In an embodiment where the partition wall 16 of the low-stage compressor 10a is cooled, a branch path 76a is provided. This branch path 76a branches from the refrigerant circulation path 72 located downstream of the condenser 74 and upstream of the expansion valve 79, and communicates with the cooling medium path 18 of the low-stage compressor 10a. The low-stage compressor 10a can employ... Figures 1-3The compressor 10 (10A to 10C) is shown. When compressor 10 (10B, 10C) is used, the refrigerant discharge path 42a or 60a is connected to the intermediate path 72 (72a). The intermediate path 72 (72a) has a lower pressure than the branch path 76a. Therefore, for the refrigerant liquid diverted from the refrigerant circulation path 72 to the branch path 76a, due to the pressure difference between the branch path 76a and the intermediate path 72 (72a), in the case of compressor 10 (10A), it is discharged to the intermediate path 72 (72a) via the cooling medium path 18 and the connecting path 62, and in the case of compressor 10 (10B, 10C), it is discharged to the intermediate path 72 (72a) via the cooling medium path 18 and the refrigerant discharge path 42a or 60a.

[0055] In the embodiment where the partition wall 16 of the advanced compressor 10b is cooled, Figure 6 The illustrated embodiment includes a branch path 76b, which branches off from the refrigerant circulation path 72 downstream of the condenser 74 and upstream of the expansion valve 79, and connects to the refrigerant circulation path 72 of the advanced compressor 10b. The advanced compressor 10b can be equipped with... Figures 1-3 The compressor 10 (10A to 10C) shown is equipped with a liquid pump 77 on the branch path 76b, and a pressure regulating valve 78 may be provided as needed. When compressor 10 (10B, 10C) is used, the refrigerant discharge path 42b or 60b, which discharges the refrigerant after cooling the partition 16 in the cooling medium path 18, is connected at any position in the refrigerant circulation path 72. The refrigerant liquid diverted from the refrigerant circulation path 72 to the branch path 76 is pressurized by the liquid pump 77, thus enabling it to be supplied to the cooling medium path 18 of the advanced compressor 10b. The refrigerant after cooling the partition 16 returns to the refrigerant circulation path 72 via the refrigerant discharge path 42b or 60b.

[0056] Preferably, the refrigerant discharge path 42b or 60b is connected to the refrigerant circulation path 72 upstream of the condenser 74 (e.g., the refrigerant circulation path 72 between the oil separator 86 and the condenser 74). Therefore, it is not necessary for the refrigerant used in the cooling partition section 16 to return to the refrigerant circulation path 72 downstream of the expansion valve 79 or the intermediate path 72 (72a). Thus, supplying refrigerant to the cooling medium path 18 does not reduce the compressor's capacity.

[0057] In the embodiment where the partition wall 16 of the advanced compressor 10b is cooled, Figure 7In the illustrated embodiment, it is not necessary to install a liquid pump 77 and a pressure regulating valve 78 on the branch path 76b. Instead, the refrigerant discharge path 42b or 60b is connected to the intermediate path 72 (72a). Since the pressure in the intermediate path 72 (72a) is lower than the pressure in the branch path 76b, the refrigerant supplied from the branch path 76b to the cooling medium path 18 can be smoothly discharged to the intermediate path 72 (72a) via the refrigerant discharge path 42b or 60b.

[0058] for Figure 6 and Figure 7 In the embodiment shown, both the low-level compressor 10a and the high-level compressor 10b have a unit for cooling the compressor. However, it is also possible to provide a cooling unit only on one of the low-level compressor 10a or the high-level compressor 10b.

[0059] Furthermore, in another embodiment, the compressor system 70 can be applied to a single two-stage compressor. When the compressor system 70 is applied to a refrigeration system, the cooling effect of the lower-stage compressor has the greatest impact on the cooling capacity. For a single two-stage compressor, both the lower-stage and higher-stage compressors are housed within a single casing. Therefore, the lower-stage compressor is susceptible to the temperature rise caused by the higher-stage compressor. By applying the compressor system 70 to a single two-stage compressor, the cooling capacity can be maintained at a higher level.

[0060] The content described in the above embodiments can be understood, for example, as follows.

[0061] 1) Regarding a compressor (10) of one type, it includes: a cylinder (12), a piston (14) configured to reciprocate within the cylinder, an intake space (Si) communicatively connected to a working chamber (Sc) formed by the cylinder and the piston, an exhaust space (Sv) communicatively connected to the working chamber, a partition wall (16) arranged to surround the working chamber and dividing the intake space and the exhaust space, and a cooling medium path (18) formed on the partition wall.

[0062] With this structure, by forming a cooling medium path on the partition separating the intake and exhaust spaces and allowing the cooling medium to flow through this path, heat input from the exhaust space to the intake space can be suppressed. This, in turn, suppresses the reduction in compressor volumetric efficiency caused by heat input from the exhaust space to the intake space. Furthermore, since the partition is located away from the compressor surface, the temperature drop on the compressor surface (e.g., the surface of the end cover 46) can be suppressed. Therefore, frost formation on the compressor surface can be prevented.

[0063] 2) Regarding another type of compressor (10), as the compressor (10) described in 1), it includes: a suction valve (20) for switching the communication state between the suction space (Si) and the working chamber (Sc), a discharge valve (22) for switching the communication state between the discharge space (Sv) and the working chamber, and a valve plate (30) for holding the suction valve and the discharge valve, wherein the cooling medium path (18) is formed on the valve plate, which is the partition wall (16).

[0064] With this structure, a cooling medium path is formed on the valve plate, and cooling of the cooling medium path suppresses heat input from the discharge space to the suction space. Therefore, it suppresses the reduction in compressor volumetric efficiency caused by heat input from the discharge space to the suction space. On the other hand, the valve plate located inside the compressor is far from the compressor surface, thus suppressing the temperature drop of the compressor surface (e.g., the surface of the end cover 46). Therefore, it is possible to suppress the formation of frost on the compressor surface.

[0065] 3) Regarding another type of compressor (10), as the compressor described in 2), it has a compressor housing (32) having the suction space (Si) and for receiving the cylinder (12) and the piston (14), the valve plate (30) having a first flow path groove (31) formed on the surface of the compressor housing, at least a portion of the cooling medium path (18) being formed by the first flow path groove.

[0066] With this structure, at least a portion of the cooling medium path is formed by the aforementioned first flow path groove, thus eliminating the need to form deep holes in the valve plate when forming the cooling medium path. Therefore, the processing for forming the cooling medium path is easier. Furthermore, the first flow path groove has an opening on the compressor housing side, allowing the cooling medium flowing in the cooling medium path to cool the suction space.

[0067] 4) Regarding another type of compressor (10), as described in 1), it comprises: an intake valve (20) for switching the communication state between the intake space (Si) and the working chamber (Sc), an exhaust valve (22) for switching the communication state between the exhaust space (Sv) and the working chamber, a valve plate (30) for maintaining the intake valve and the exhaust valve, and a compressor housing (32) for receiving the cylinder and the piston, wherein a second flow path groove (34) is formed on the surface of the compressor housing on the valve plate side, and at least a portion of the cooling medium path (18) is formed by the second flow path groove.

[0068] Based on this structure, the aforementioned cooling medium path can be formed by machining the surface of the compressor housing, thus making it easy to form the cooling medium path.

[0069] 5) Regarding another type of compressor (10), as described in 4), it has an insulating gasket (44) that is clamped between the valve plate (30) and the compressor housing (32).

[0070] With this structure, the heat input from the discharge space to the suction space located on the compressor housing side can be further suppressed due to the aforementioned heat-insulating sealing gasket.

[0071] 6) Regarding another type of compressor (10), as any of the compressors described in 3) to 5), it has an end cover (46) that forms the discharge space (Sv) together with the valve plate (30), the outer peripheral edge of the valve plate being sandwiched between the outer peripheral edge of the compressor housing (32) and the outer peripheral edge of the end cover.

[0072] With this structure, the three outer peripheries of the end cover, valve plate, and compressor housing are fastened together using bolts or other fastening tools, making valve plate installation easy. Furthermore, since the outer periphery of the valve plate is exposed, it is easy to connect the refrigerant supply pipe to the cooling medium path formed on the valve plate from the outside.

[0073] 7) Regarding a compressor system (70) of one type, it comprises: the compressor (10 (10A, 10B, 10C)) described above, a refrigerant circulation path (72) communicating with the suction space (Si) and the discharge space (Sv) of the compressor, a condenser (74) for condensing the discharge gas discharged from the discharge space, at least one branch path (76) branching from the refrigerant circulation path on the downstream side of the condenser and communicating with the cooling medium path (18), and a liquid pump (77) provided in the branch path.

[0074] With this structure, the refrigerant liquid flowing in the aforementioned branch path is pressurized by the liquid pump, thus enabling the supply of refrigerant liquid to the cooling medium path. This cools the partition wall within the compressor, thereby suppressing the decrease in compressor volumetric efficiency caused by heat input from the discharge space to the suction space. Therefore, when this compressor system is applied to refrigeration systems or heat pump systems, it can suppress the decrease in COP (coefficient of performance). Furthermore, since the partition wall within the compressor is located far from the compressor surface, the temperature drop of the compressor surface can be suppressed. This, in turn, prevents frost formation on the compressor surface.

[0075] 8) Regarding another type of compressor system (70), as the compressor system described in 7), it has a refrigerant discharge path (42, 60) that returns the cooling medium discharged from the cooling medium path (18) of the compressor (10 (10A, 10B)) to the refrigerant circulation path (72), the refrigerant discharge path being connected to the refrigerant circulation path between the compressor and the condenser (74).

[0076] With this structure, the refrigerant liquid, pressurized by the liquid pump and supplied to the cooling medium path, can return to the refrigerant circulation path on the high-pressure side between the compressor and the condenser. Therefore, the refrigerant used in the cooling partition section can be used as the compressor's working refrigerant, and thus, supplying refrigerant for cooling to the cooling medium path does not reduce the compressor's capacity.

[0077] 9) Regarding a compressor system of one type, it comprises: the compressor (10 (10B, 10C)) described above, a refrigerant circulation path (72) connecting the suction space (Si) and the discharge space (Sv) of the compressor, a condenser (74) for condensing the discharge gas discharged from the discharge space, an expansion valve (79) for depressurizing the condensate of the discharge gas condensed in the condenser, at least one branch path (76) branching from the refrigerant circulation path between the condenser and the expansion valve and communicating with the cooling medium path (18), and a refrigerant discharge path (42, 60) for returning the cooling medium discharged from the cooling medium path of the compressor to the refrigerant circulation path between the expansion valve and the compressor.

[0078] With this structure, since the refrigerant circulation path between the expansion valve and the compressor has a lower pressure than the branch path, even without a liquid pump on the branch path, the refrigerant supplied to the cooling medium path can return to the refrigerant circulation path in the low-pressure area via the refrigerant discharge path.

[0079] 10) Regarding a compressor system (70) of one type, it includes: a refrigerant circulation path (72), a low-stage compressor (10a) and a high-stage compressor (10b) arranged in series in the refrigerant circulation path, and a condenser (74) for condensing the discharge gas discharged from the discharge space of the high-stage compressor. The low-stage compressor is composed of the compressor (10 (10A to 10C)) described above, and includes: a branch path (76a) that branches off from the refrigerant circulation path on the downstream side of the condenser (74) and communicates with the cooling medium path of the low-stage compressor, and a refrigerant discharge path (42a, 60a) that returns the cooling medium discharged from the cooling medium path (18) of the low-stage compressor to the refrigerant circulation path (intermediate path 72 (72a)) between the low-stage compressor and the high-stage compressor.

[0080] According to this structure, since the pressure in the intermediate path is lower than that in the branch path 76a, the refrigerant gas that has been cooled in the cooling medium path of the lower compressor can return to the intermediate path via the refrigerant discharge path.

[0081] 11) Regarding a compressor system (70) of one type, it includes: a refrigerant circulation path (72), a low-stage compressor (10a) and a high-stage compressor (10b) arranged in series in the refrigerant circulation path, and a condenser (74) for condensing the discharge gas discharged from the discharge space (Sv) of the high-stage compressor, the high-stage compressor being composed of the compressor (10 (10A to 10C)) described above, and including: a branch path (76b) branching from the refrigerant circulation path on the downstream side of the condenser and communicating with the cooling medium path (18) of the high-stage compressor, a liquid pump (77) arranged in the branch path, and a refrigerant discharge path (42b, 60b) for returning the cooling medium discharged from the cooling medium path of the high-stage compressor to the refrigerant circulation path.

[0082] According to this structure, the refrigerant liquid supplied from the aforementioned branch path to the cooling medium path of the advanced compressor is pressurized by the liquid pump, thus enabling it to be supplied to the cooling medium path of the advanced compressor, and allowing the refrigerant that has been cooled in the partition section in the refrigerant discharge path to return to the refrigerant circulation path via the refrigerant discharge path.

[0083] 12) Regarding a compressor system (70) of one type, it includes: a refrigerant circulation path (72), a low-stage compressor (10a) and a high-stage compressor (10b) arranged in series in the refrigerant circulation path, and a condenser (74) for condensing the discharge gas discharged from the discharge space (Sv) of the high-stage compressor, the high-stage compressor being composed of the compressors (10 (10B, 10C)) described above, and including: a branch path (76b) that branches off from the refrigerant circulation path on the downstream side of the condenser and communicates with the cooling medium path of the high-stage compressor, and a refrigerant discharge path (42b, 60b) that returns the cooling medium discharged from the cooling medium path (18) of the high-stage compressor to the refrigerant circulation path (intermediate path 72 (72a)) arranged between the low-stage compressor and the high-stage compressor.

[0084] According to this structure, since the refrigerant liquid flowing in the branch path has a higher pressure than that in the intermediate path, the refrigerant liquid supplied from the branch path to the cooling medium path of the advanced compressor can return to the intermediate path via the refrigerant discharge path after cooling the partition section.

[0085] Explanation of reference numerals in the attached figures

[0086] 10 (10A, 10B, 10C, 10a, 10b) - Compressor; 10a - Low-stage compressor; 10b - High-stage compressor; 12 - Cylinder block; 14 - Piston; 16 - Divider section; 18 - Cooling medium path; 20 - Suction valve; 22 - Discharge valve; 24 - Crankshaft; 26 - Connecting rod; 28 - Valve cover; 30 - Valve plate; 31 - First flow path groove; 31a - Opening; 32 - Compressor housing; 33, 56 - Through hole; 34 - Second flow path groove; 36 - Supply path; 38, 52 - Supply pipe; 39 - Throttling valve; 40. 58 - Discharge path; 42, 42a, 42b, 60, 60a, 60b - Refrigerant discharge path; 44 - Insulation gasket; 46 - End cap; 46a - Opening; 48, 54 - Bolts; 50 - Injector nozzle; 62 - Connecting path; 70 (70A, 70B) - Compressor system; 72 - Refrigerant circulation path; 74 - Condenser; 76, 76a, 76b - Branch paths; 78 - Expansion valve; 80 - Evaporator; 82 - Suction chamber; 84 - Discharge chamber; Sc - Working chamber; Si - Suction space; Sv - Discharge space.

Claims

1. A compressor comprising: Cylinder block; A piston configured to reciprocate within the cylinder; The compressor housing houses the cylinder and the piston, and has a built-in suction space that can communicate with the working chamber formed by the cylinder and the piston. An end cap forms a discharge space that can communicate with the working chamber; A partition is configured to surround the working chamber and divide the intake space and the exhaust space; Cooling medium path; An intake valve is used to switch the connection between the intake space and the working chamber; A discharge valve, used to switch the communication state between the discharge space and the working chamber; and A valve plate, which serves to hold the intake valve and the discharge valve in place. The cooling medium path is formed on the valve plate, which serves as the partition separating the suction space within the compressor housing and the discharge space within the end cover, or on the surface of the valve plate side of the compressor housing.

2. The compressor according to claim 1, characterized in that, The valve plate has a first flow path groove formed on the surface of the compressor housing. At least a portion of the cooling medium path is formed by the first flow path groove.

3. The compressor according to claim 1, characterized in that, The compressor housing has a second flow path groove formed on the surface of the valve plate side. At least a portion of the cooling medium path is formed by the second flow channel.

4. The compressor according to claim 3, characterized in that, It has an insulating gasket, which is clamped between the valve plate and the compressor housing.

5. The compressor according to any one of claims 2 to 4, characterized in that, The outer periphery of the valve plate is sandwiched between the outer periphery of the compressor housing and the outer periphery of the end cover.

6. A compressor system comprising: The compressor according to any one of claims 1 to 5; A refrigerant circulation path that communicates with the compressor's suction space and discharge space; A condenser for condensing exhaust gas discharged from the exhaust space; At least one branch path that branches off from the refrigerant circulation path and communicates with the cooling medium path on the downstream side of the condenser; and A liquid pump is located in the branch path.

7. The compressor system according to claim 6, characterized in that, It has a refrigerant discharge path that returns the cooling medium discharged from the compressor's cooling medium path to the refrigerant circulation path. The refrigerant discharge path is connected to the refrigerant circulation path between the compressor and the condenser.

8. A compressor system comprising: The compressor according to any one of claims 1 to 5; A refrigerant circulation path that communicates with the compressor's suction space and discharge space; A condenser for condensing exhaust gas discharged from the exhaust space; An expansion valve that reduces the pressure of the condensate of the discharged gas that has condensed in the condenser. At least one branch path that branches off from the refrigerant circulation path between the condenser and the expansion valve and communicates with the cooling medium path; and A refrigerant discharge path that returns the cooling medium discharged from the compressor's cooling medium path to the refrigerant circulation path between the expansion valve and the compressor.

9. A compressor system comprising: Refrigerant circulation path; The low-level compressor and the high-level compressor are arranged in series in the refrigerant circulation path; as well as A condenser, used to condense the exhaust gas discharged from the discharge space of the advanced compressor. The low-level compressor is composed of the compressor described in any one of claims 1 to 5. have: A branch path that branches off from the refrigerant circulation path on the downstream side of the condenser and connects to the cooling medium path of the lower-stage compressor; and A refrigerant discharge path that returns the cooling medium discharged from the cooling medium path of the lower compressor to the refrigerant circulation path between the lower compressor and the higher compressor.

10. A compressor system comprising: Refrigerant circulation path; The low-level compressor and the high-level compressor are arranged in series in the refrigerant circulation path; as well as A condenser, used to condense the exhaust gas discharged from the discharge space of the advanced compressor. The advanced compressor is composed of the compressor described in any one of claims 1 to 5. have: A branch path that branches off from the refrigerant circulation path on the downstream side of the condenser and communicates with the cooling medium path of the advanced compressor; A liquid pump is located in the branch path; as well as A refrigerant discharge path that returns the cooling medium discharged from the cooling medium path of the advanced compressor to the refrigerant circulation path.

11. A compressor system comprising: Refrigerant circulation path; The low-level compressor and the high-level compressor are arranged in series in the refrigerant circulation path; as well as A condenser, used to condense the exhaust gas discharged from the discharge space of the advanced compressor. The advanced compressor is composed of the compressor described in any one of claims 1 to 5. have: A branch path that branches off from the refrigerant circulation path on the downstream side of the condenser and communicates with the cooling medium path of the advanced compressor; and A refrigerant discharge path that returns the cooling medium discharged from the cooling medium path of the advanced compressor to the refrigerant circulation path located between the low-level compressor and the advanced compressor.

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