JP2006266636A - Freezing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit pressure pulsation at the outlet side of an expander. <P>SOLUTION: A buffer vessel 71 is connected with an outflow port 33 of an expanding mechanism 60. The buffer vessel 71 is formed into the cylindrical shape extending in the refrigerant flowing direction, and having a cross-sectional area larger than that of the outflow port 33. A straightening vane 75 having a disc-shaped mesh portion 75a is mounted inside of the buffer vessel 71. Pressure fluctuation is reduced by pressure supply and pressure suction of the buffer vessel 71, and droplet refrigerant is miniaturized when it passes through the straightening vane 75. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus, and particularly relates to measures for reducing pressure pulsation.

  Conventionally, a refrigeration apparatus for a vapor compression refrigeration cycle using carbon dioxide as a refrigerant is known. This type of refrigeration apparatus includes a refrigerant circuit in which a compressor, a cooler, an expander, and an evaporator are sequentially connected (see, for example, Patent Document 1).

In the refrigerant circuit, the refrigerant is compressed to a supercritical state by a compressor and cooled by a cooler. The cooled refrigerant is expanded and decompressed by an expander, and then repeatedly circulates by evaporating by an evaporator and returning to the compressor. In this refrigeration apparatus, for example, a cooler is installed indoors and used as a heating apparatus.
JP 2000-234814 A

  However, the conventional refrigeration apparatus described above has a problem that large vibrations are generated particularly on the outlet side of the expander. Specifically, when a positive displacement type expander is used, pressure pulsation occurs on the inlet side and outlet side of the expander because the suction flow rate in the suction process and the discharge flow rate in the discharge process are not constant. And vibration occurs. Further, since the gas-liquid two-phase refrigerant flows out of the expander, there is a problem that a larger vibration is generated on the outlet side of the expander when the droplet collides with a pipe or the like. Therefore, on the outlet side of the expander, there is a high possibility of causing damage to the equipment due to vibration, and the reliability may be significantly impaired.

  The present invention has been made in view of such points, and an object of the present invention is to reduce at least pressure pulsation and reduce vibration on the outlet side of the expander.

  1st invention presupposes the freezing apparatus provided with the refrigerant circuit (20) which connects a positive displacement expander (60) by piping, and performs a vapor compression refrigeration cycle. The refrigerant circuit (20) has a refrigerant cross-sectional area larger than that of the outlet side pipe in the middle of the outlet side pipe of the positive displacement expander (60) and flows out of the positive displacement expander (60). The flow path expansion part (71) which relieves the pressure fluctuation of the refrigerant | coolant to perform is provided.

  In the above invention, the flow path expanding portion (71) constitutes a pressure buffering space for relaxing the pressure fluctuation of the refrigerant flowing out of the positive displacement expander (60). Therefore, the pressure fluctuation (pressure pulsation) generated on the outlet side of the positive displacement expander (60) is alleviated by the flow path expanding portion (71). Thereby, the vibration of the whole apparatus resulting from a pressure fluctuation is suppressed.

  The second invention is premised on a refrigeration apparatus including a refrigerant circuit (20) in which a positive displacement expander (60) is connected to a pipe to perform a vapor compression refrigeration cycle. The refrigerant circuit (20) is a cylinder that is formed in the middle of the outlet side pipe of the positive displacement expander (60) so that the cross-sectional area of the refrigerant is larger than that of the outlet side pipe and extends along the refrigerant flow direction. The channel-shaped enlarged channel part (71) is provided.

  In the above-described invention, for example, as shown in FIG. 3, the flow path expanding portion (71) is formed in a cylindrical container extending in the refrigerant flow direction, and the inside of the container constitutes a pressure buffering space. Specifically, when the amount of refrigerant flowing out of the positive displacement expander (60) increases and the pressure rises, the increased amount of refrigerant is stored in the flow path expanding portion (71) and the pressure is absorbed. The Conversely, if the refrigerant flow out of the positive displacement expander (60) decreases and the pressure drops, the reduced amount of refrigerant flows out of the flow path enlargement part (71) to the outlet side pipe and pressure. Is supplied. That is, the flow path expanding section (71) alleviates the pressure fluctuation by adjusting the refrigerant flow rate on the outlet side according to the pressure fluctuation on the outlet side of the positive displacement expander (60). Thereby, the pressure fluctuation in the exit side of positive displacement expander (60) is suppressed, and the vibration of the whole apparatus is suppressed.

  In a third aspect based on the second aspect, the flow path expanding portion (71) is arranged in a state extending in the vertical direction, and the refrigerant flowing in from the upper part flows vertically downward and flows out from the lower surface. Thus, it is connected to the outlet side piping of the positive displacement expander (60).

  In the above invention, as shown in FIG. 10, the flow path expanding portion (71) is formed in a cylindrical container extending in the vertical direction, that is, in the vertical direction. Then, the refrigerant that has flowed out of the positive displacement expander (60) flows in from the upper part of the flow path expanding portion (71), flows vertically downward, and flows out from the lower surface to the outlet side pipe, so that liquid refrigerant accumulates on the lower surface. Can be prevented. That is, the refrigerant that has flowed out of the positive displacement expander (60) is in a gas-liquid two-phase state, but the liquid refrigerant surely flows out without accumulating in the flow path expanding portion (71).

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a refrigerant rectifying means (75, 76) is provided inside the flow path expanding portion (71).

  In the above invention, the flow of the refrigerant that has flowed into the flow path expanding portion (71) is stabilized by the rectifying means (75, 76). That is, the flow of the liquid refrigerant out of the refrigerant flowing into the flow path expanding portion (71) is stabilized, so that the liquid refrigerant can be prevented from colliding violently with an inner wall such as a pipe. Therefore, the rectifying means (75, 76) suppresses vibrations generated when the liquid refrigerant collides with the pipe wall or the like. As a result, in addition to the effect of suppressing the pressure pulsation, the vibration of the entire device is further suppressed.

  Further, a fifth invention is the rectifying plate according to the fourth invention, wherein the rectifying means (76) is formed in a plate shape having a plurality of through holes, and is provided facing the refrigerant flow direction.

  In the above invention, as shown in FIG. 6, the refrigerant that has flowed into the flow path expanding portion (71) flows through the plurality of through holes of the rectifying plate, so that the flow of the refrigerant is stabilized. Furthermore, when the refrigerant passes through the through-hole, the flow velocity of the refrigerant increases, so that the liquid refrigerant is refined with the momentum of the flow velocity. Thereby, even if a liquid refrigerant collides with a pipe wall etc., the impact is small. Therefore, the vibration of the device is further suppressed.

  In addition, a sixth invention is the rectifying plate according to the fourth invention, wherein the rectifying means (75) is formed of a plate-like mesh member and is provided facing the refrigerant flow direction.

  In the above invention, as shown in FIG. 3, the refrigerant that has flowed into the flow path expanding portion (71) flows through the mesh portion of the rectifying plate, so that the flow of the refrigerant is stabilized. Furthermore, when the refrigerant passes through the mesh portion, the liquid refrigerant contained in the refrigerant is refined by the mesh portion. Thereby, even if a liquid refrigerant collides with a pipe wall etc., the impact is small. Therefore, the vibration of the device is further suppressed.

  Further, according to a seventh invention, in any one of the second to fourth inventions, the flow passage expanding portion (71) has a through-hole and partitions the interior in the refrigerant flow direction ( 77).

  In the above invention, for example, as shown in FIG. 7, the interior of the flow path enlarged portion (71) is partitioned into the upstream space and the downstream space by the partition plate (77). That is, the flow path expanding portion (71) has, for example, two pressure buffering spaces. A through hole is formed in the partition plate (77), and the upstream space and the downstream space communicate with each other through the through hole. Therefore, in this flow path enlarged portion (71), the pressure fluctuation of the refrigerant on the outlet side of the expansion mechanism (60) is relieved in two stages. If two or more partition plates (77) are used to form three or more pressure buffering spaces, the pressure fluctuation is alleviated in multiple steps. Thereby, the impact accompanying sudden pressure fluctuation is suppressed. Thereby, the vibration of the whole apparatus is further suppressed.

  In an eighth aspect based on the first aspect or the second aspect, the refrigerant is carbon dioxide.

  In the above invention, since carbon dioxide is used as the refrigerant circulating in the refrigerant circuit (20), it is possible to provide devices and devices that are friendly to the global environment. In particular, in the case of carbon dioxide, since it is compressed to a critical pressure state, the pressure fluctuation at the outlet side of the positive displacement expander (60) increases accordingly, but this pressure fluctuation is reliably and effectively suppressed.

  Therefore, according to the present invention, in the middle of the outlet side pipe of the positive displacement expander (60), the refrigerant cross-sectional area is larger than that of the outlet side pipe, and the refrigerant flows out of the positive displacement expander (60). Since the flow path enlargement part (71) for reducing the pressure fluctuation is provided, the vibration of the device due to the pressure fluctuation can be suppressed. As a result, damage to equipment can be prevented.

  According to the second aspect of the present invention, in the middle of the outlet side pipe of the positive displacement expander (60), a cylinder having a refrigerant cross-sectional area larger than the outlet side pipe and extending along the refrigerant flow direction. Since the channel enlarged portion (71) formed in the shape is provided, it is possible to reliably supply and absorb pressure from the channel enlarged portion (71) to the outlet side pipe. Thereby, since a pressure fluctuation can be suppressed, the vibration of the whole apparatus can be suppressed.

  According to the third aspect of the invention, the refrigerant is arranged so that the refrigerant flows vertically downward and flows out from the lower surface in the flow passage expanding portion (71), so that the liquid refrigerant is accumulated in the flow passage expanding portion (71). Can be prevented.

  Further, according to the fourth to sixth inventions, since the refrigerant rectifying means (75, 76) is provided in the flow path expanding portion (71), the flow of the refrigerant can be reliably stabilized. Thereby, the collision of the liquid refrigerant to the piping wall can be suppressed. Therefore, vibration generated by the collision of the liquid refrigerant can be suppressed.

  Moreover, according to the seventh aspect, since the partition plate (77) is provided in the flow path expanding portion (71) to form a plurality of pressure buffering spaces inside, the pressure fluctuation can be alleviated in multiple stages. Can do. Therefore, an impact caused by a sudden pressure fluctuation can be reduced. Thereby, the vibration of the whole apparatus can be suppressed further, and damage to apparatus can be prevented further.

  In addition, according to the eighth invention, since carbon dioxide is used as the refrigerant circulating in the refrigerant circuit (20), it is possible to provide equipment and devices that are friendly to the global environment. In particular, in the case of carbon dioxide, since the pressure is compressed to a critical pressure state, the pressure fluctuation increases accordingly, but the pressure fluctuation can be reliably and effectively suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
As shown in FIG. 1, the air conditioner (10) of Embodiment 1 constitutes a refrigeration apparatus according to the present invention. The air conditioner (10) has an outdoor heat exchanger (23), an indoor heat exchanger (24), two four-way selector valves (21, 22), and a compression / expansion unit (30) connected to each other in a closed circuit. The formed refrigerant circuit (20) is provided. The refrigerant circuit (20) is configured so that carbon dioxide (CO ₂ ) is filled as a refrigerant, and the refrigerant circulates to perform a vapor compression refrigeration cycle.

  The outdoor heat exchanger (23) constitutes a heat source side heat exchanger, and the indoor heat exchanger (24) constitutes a use side heat exchanger. The outdoor heat exchanger (23) and the indoor heat exchanger (24) are both cross-fin type fin-and-tube heat exchangers. The outdoor heat exchanger (23) is configured such that the refrigerant circulating in the refrigerant circuit (20) exchanges heat with outdoor air. The indoor heat exchanger (24) is configured such that the refrigerant circulating in the refrigerant circuit (20) exchanges heat with room air.

  The compression / expansion unit (30) includes a compression mechanism (50), an electric motor (40), and an expansion mechanism (60) housed in a casing. The compression mechanism (50), the electric motor (40), and the expansion mechanism (60) are connected in this order by a shaft (45) that is a rotating shaft. The compression mechanism (50) constitutes a rotary piston type rotary compressor. The expansion mechanism (60) is an oscillating piston type rotary expander, and constitutes a positive displacement expander (60) according to the present invention.

  The compression / expansion unit (30) includes a suction port (34) through which the refrigerant in the refrigerant circuit (20) is sucked into the compression mechanism (50), and the refrigerant compressed by the compression mechanism (50) into the refrigerant circuit (20). A discharge port (31) for discharging is provided. Further, the compression / expansion unit (30) guides the refrigerant in the refrigerant circuit (20) to the expansion mechanism (60), and the inflow port (32), and the refrigerant expanded by the expansion mechanism (60) to the refrigerant circuit (20). An outflow port (33) is provided. The details of the expansion mechanism (60) will be described later.

  The first four-way selector valve (21) has four ports. The first four-way selector valve (21) has a first port at the discharge port (31) of the compression / expansion unit (30) and a second port at the gas side end which is one end of the indoor heat exchanger (24). The third port is connected to the gas side end which is one end of the outdoor heat exchanger (23), and the fourth port is connected to the suction port (34) of the compression / expansion unit (30). The first four-way selector valve (21) has a state in which the first port and the second port communicate with each other and a state in which the third port and the fourth port communicate with each other (state indicated by a solid line in FIG. 1), The first port and the third port communicate with each other, and the second port and the fourth port communicate with each other (state indicated by a broken line in FIG. 1).

  The second four-way selector valve (22) has four ports. The second four-way selector valve (22) has a liquid-side end portion where the first port is the outflow port (33) of the compression / expansion unit (30) and the second port is the other end of the outdoor heat exchanger (23). Further, the third port is connected to the liquid side end which is the other end of the indoor heat exchanger (24), and the fourth port is connected to the inflow port (32) of the compression / expansion unit (30). The second four-way selector valve (22) includes a state in which the first port and the second port communicate with each other and a state in which the third port and the fourth port communicate with each other (state indicated by a solid line in FIG. 1), The first port and the third port communicate with each other, and the second port and the fourth port communicate with each other (state indicated by a broken line in FIG. 1).

  The expansion mechanism (60) will be described with reference to FIG. 2A shows a cross section perpendicular to the central axis of the shaft (45), and FIG. 2B shows a cross section taken longitudinally along the central axis of the shaft (45). It is a thing.

  The expansion mechanism (60) includes a front head (61), a rear head (62), a cylinder (63), and a rotary piston (67).

  The cylinder (63) has one end face closed by a front head (61) and the other end face closed by a rear head (62).

  The rotary piston (67) is formed in an annular shape or a cylindrical shape, and is accommodated in the cylinder (63). The rotary piston (67) has an outer peripheral surface in sliding contact with the inner peripheral surface of the cylinder (63) and both end surfaces in sliding contact with the front head (61) and the rear head (62). In the cylinder (63), an expansion chamber (65) is formed between the inner peripheral surface and the outer peripheral surface of the rotary piston (67).

  A shaft (45) passes through the rotary piston (67). The shaft (45) includes a main shaft portion (46), and an eccentric portion (47) having a larger diameter than the outer diameter of the main shaft portion (46) is formed at one end of the main shaft portion (46). The eccentric part (47) is eccentric by a predetermined amount from the axis of the main shaft part (46). The eccentric portion (47) is rotatably fitted to the rotary piston (67).

  The rotary piston (67) is integrally provided with a blade (68) formed in a plate shape. The blade (68) projects outward from the outer peripheral surface of the rotary piston (67), and partitions the expansion chamber (65) in the cylinder (63) into a high pressure side (suction / expansion side) and a low pressure side (discharge side). It is configured as follows.

  The cylinder (63) is provided with a pair of bushes (69). The pair of bushes (69) sandwich the blade (68) and support the blade (68) so as to be rotatable and reciprocated.

  The inflow port (32) passes through the rear head (62), and the terminal end is open in a range where it slides on the eccentric part (47) on the inner surface of the rear head (62). That is, the inflow port (32) is open at a position where the end does not directly communicate with the expansion chamber (65). On the other hand, the outflow port (33) passes through the cylinder (63) in the radial direction and opens toward the low pressure side of the expansion chamber (65). The inflow port (32) and the outflow port (33) are extended to the outside of the casing of the compression / expansion unit (30) by piping.

  The rear head (62) is formed with a groove-shaped channel (9a). As shown in FIG. 2 (A), one end of the groove-like passage (9a) is positioned slightly inside the inner peripheral surface of the cylinder (63), while the other end is arranged with the rear head (62) and the eccentric portion (47). ). The groove-shaped passage (9a) can communicate with the expansion chamber (65).

  The eccentric part (47) of the shaft (45) is formed with a groove-shaped communication passage (9b). As shown in FIG. 2A, the communication passage (9b) is formed in an arc shape extending along the outer periphery of the eccentric portion (47). And the said communication channel | path (9b) is comprised so that an inflow port (32) and a groove-shaped channel | path (9a) may communicate intermittently by moving with rotation of a shaft (45).

  The refrigerant circuit (20) is provided with a pressure buffering means (70) for suppressing pressure fluctuation (pressure pulsation) in the outlet side piping of the expansion mechanism (60) as a feature of the present invention. The pressure buffer means (70) includes a buffer container (71). The buffer container (71) is connected in the middle of the outlet side piping of the expansion mechanism (60).

  As shown in FIG. 3, the buffer container (71) is generally formed in a cylindrical container. The buffer container (71) includes a body part (72), an inlet side end part (73), and an outlet side end part (74). The trunk portion (72) is formed in a cylindrical shape with a circular cross section. The inlet side end portion (73) and the outlet side end portion (74) are formed continuously at both ends of the body portion (72) to close the both ends. The volume of the buffer container (71) is formed larger than the volume of the expansion chamber (65) of the expansion mechanism (60), and preferably 10 times or more the volume of the expansion chamber (65).

  The outlet port (33) of the expansion mechanism (60) is connected to the center of the inlet side end (73), and the center of the outlet side end (74) is a part of the refrigerant pipe. A connecting pipe (P) connected to the first port of the two-way switching valve (22) is connected. This connecting pipe (P) constitutes the outlet side piping of the expansion mechanism (60) together with the outflow port (33). The buffer container (71) is coaxially connected to the outflow port (33) and the connection pipe (P), and the refrigerant flowing in from the outflow port (33) flows horizontally and flows out to the connection pipe (P). That is, the buffer container (71) is formed in a cylindrical shape extending along the refrigerant flow direction. As described above, since the buffer container (71) is formed in a cylindrical shape, the flow resistance of the refrigerant is reduced as compared with a case where the buffer container (71) is formed in a cylindrical shape having a rectangular cross section, for example.

  The cross-sectional area of the trunk portion (72) is much larger than the cross-sectional areas of the outflow port (33) and the connecting pipe (P). When the refrigerant pressure at the outflow port (33) increases, the buffer container (71) absorbs and stores the refrigerant at the outflow port (33). Conversely, when the refrigerant pressure at the outflow port (33) decreases, The refrigerant is discharged to the outflow port (33). That is, the buffer container (71) constitutes a flow passage expanding portion in the outlet side piping of the expansion mechanism (60), and the inside thereof constitutes a pressure buffering space.

  A current plate (75) is provided inside the buffer container (71). The rectifying plate (75) constitutes a rectifying means for the refrigerant that stabilizes the flow of the refrigerant.

  The rectifying plate (75) is formed in a disc shape as a whole. The rectifying plate (75) has an outer diameter that is substantially the same as the inner diameter of the body (72) of the buffer container (71), and the outer periphery is attached in contact with the entire inner periphery of the body (72). That is, this baffle plate (75) is located so as to oppose the refrigerant flow direction. And as shown in FIG.3 (B), the said baffle plate (75) has the mesh part (75a) by which the whole inside of outer periphery was formed in mesh shape. The rectifying plate (75) is configured such that the refrigerant of the droplets is refined when the refrigerant passes through the mesh portion (75a). The refrigerant flowing into the buffer container (71) flows downstream through the mesh portion (75a) of the rectifying plate (75). The rectifying plate (75) is provided near the inlet side end (73) inside the buffer container (71). FIG. 3B shows a cross section taken along line XX in FIG.

-Driving action-
Next, the operation of the air conditioner (10) will be described. Here, the operation of the air conditioner (10) during the cooling operation and the heating operation will be described, and then the operation of the expansion mechanism (60) will be described.

<Cooling operation>
During this cooling operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to the state shown by the broken line in FIG. ) Is energized, the refrigerant circulates in the refrigerant circuit (20) and a vapor compression refrigeration cycle is performed.

  The high-pressure refrigerant compressed by the compression mechanism (50) is discharged from the compression / expansion unit (30) through the discharge port (31). In this state, the pressure of the high-pressure refrigerant is higher than its critical pressure. This high-pressure refrigerant is sent to the outdoor heat exchanger (23) through the first four-way switching valve (21). In the outdoor heat exchanger (23), the high-pressure refrigerant that has flowed in radiates heat to the outdoor air.

  The high-pressure refrigerant radiated by the outdoor heat exchanger (23) passes through the second four-way switching valve (22) and flows into the expansion chamber (65) of the expansion mechanism (60) from the inflow port (32). In the expansion chamber (65), the high-pressure refrigerant expands, and the internal energy is converted into the rotational power of the shaft (45). The low-pressure refrigerant after expansion flows out of the compression / expansion unit (30) through the outflow port (33), and is sent to the indoor heat exchanger (24) through the second four-way switching valve (22).

  In the indoor heat exchanger (24), the low-pressure refrigerant that has flowed in absorbs heat from the room air and evaporates, thereby cooling the room air. The low-pressure gas refrigerant discharged from the indoor heat exchanger (24) passes through the first four-way switching valve (21) and is sucked into the compression mechanism (50) of the compression / expansion unit (30) from the suction port (34). . The compression mechanism (50) compresses and sucks the sucked refrigerant again.

<Heating operation>
In this heating operation, the first four-way selector valve (21) and the second four-way selector valve (22) are switched to the state shown by the solid line in FIG. ) Is energized, the refrigerant circulates in the refrigerant circuit (20) and a vapor compression refrigeration cycle is performed.

  The high-pressure refrigerant compressed by the compression mechanism (50) is discharged from the compression / expansion unit (30) through the discharge port (31). In this state, the pressure of the high-pressure refrigerant is higher than its critical pressure. This high-pressure refrigerant is sent to the indoor heat exchanger (24) through the first four-way switching valve (21). In the indoor heat exchanger (24), the high-pressure refrigerant that has flowed in dissipates heat to the room air, and the room air is heated.

  The high-pressure refrigerant radiated by the indoor heat exchanger (24) passes through the second four-way switching valve (22) and flows into the expansion chamber (65) of the expansion mechanism (60) from the inflow port (32). In the expansion chamber (65), the high-pressure refrigerant expands, and the internal energy is converted into the rotational power of the shaft (45). The low-pressure refrigerant after expansion flows out of the compression / expansion unit (30) through the outflow port (33), and is sent to the outdoor heat exchanger (23) through the second four-way switching valve (22).

  In the outdoor heat exchanger (23), the low-pressure refrigerant that has flowed in absorbs heat from the outdoor air and evaporates. The low-pressure gas refrigerant discharged from the outdoor heat exchanger (23) passes through the first four-way switching valve (21) and is sucked from the suction port (34) into the compression mechanism (50) of the compression / expansion unit (30). . The compression mechanism (50) compresses and sucks the sucked refrigerant again.

<Operation of expansion mechanism>
The operation of the expansion mechanism (60) will be described with reference to FIG. When high-pressure refrigerant in a supercritical state flows into the expansion chamber (65) of the expansion mechanism (60), the shaft (45) rotates counterclockwise in each drawing of FIG. FIG. 4 shows the rotation angle of the shaft (45) at every 45 °.

  When the rotation angle of the shaft (45) is 0 °, the end of the inflow port (32) is blocked by the end face of the eccentric portion (47). At this time, the expansion chamber (65) is in a state of being blocked from the inflow port (32), and the high-pressure refrigerant does not flow into the expansion chamber (65).

  When the rotation angle of the shaft (45) is 45 °, the inflow port (32) is in communication with the communication passage (9b). The communication passage (9b) also communicates with the groove-like passage (9a). The groove-like passage (9a) is in a state in which the upper end portion in FIG. 4 is disengaged from the end face of the rotary piston (67) and communicates with the high-pressure side of the expansion chamber (65). At this time, the expansion chamber (65) is in communication with the inflow port (32) via the groove-shaped passage (9a) and the communication passage (9b), and the high-pressure refrigerant flows into the high-pressure side of the expansion chamber (65). . That is, inflow of the high-pressure refrigerant into the expansion chamber (65) is started until the rotation angle of the shaft (45) reaches 0 ° to 45 °.

  When the rotation angle of the shaft (45) is 90 °, the expansion chamber (65) is still in communication with the inflow port (32) through the groove-like passage (9a) and the communication passage (9b). Yes. Therefore, the high-pressure refrigerant continues to flow into the high-pressure side of the expansion chamber (65) until the rotation angle of the shaft (45) reaches 45 ° to 90 °.

  When the rotation angle of the shaft (45) is 135 °, the communication passage (9b) is in a state of being disconnected from both the groove-like passage (9a) and the inflow port (32). At this time, the expansion chamber (65) is in a state of being disconnected from the inflow port (32), and the high-pressure refrigerant does not flow into the expansion chamber (65). That is, the inflow of the high-pressure refrigerant into the expansion chamber (65) is completed until the rotation angle of the shaft (45) reaches 90 ° to 135 °.

  When the inflow of the high-pressure refrigerant into the expansion chamber (65) is completed, the high-pressure side of the expansion chamber (65) becomes a closed space, and the internal refrigerant expands. That is, as shown in each drawing of FIG. 4, the shaft (45) rotates and the volume on the high pressure side of the expansion chamber (65) increases. Meanwhile, the low-pressure refrigerant after expansion continues to be discharged through the outflow port (33) from the low pressure side of the expansion chamber (65) communicating with the outflow port (33).

  The expansion of the refrigerant in the expansion chamber (65) is caused by the contact portion between the rotary piston (67) and the cylinder (63) at the outflow port (the rotation angle of the shaft (45) from 135 ° to 36 °). Continue until 33) is reached. When the contact portion between the rotary piston (67) and the cylinder (63) crosses the outflow port (33), the expansion chamber (65) communicates with the outflow port (33), and discharge of the expanded refrigerant is started. The Thereafter, when the contact portion between the rotary piston (67) and the cylinder (63) passes through the outflow port (33), the expansion chamber (65) is shut off from the outflow port (33), and the discharge of the expanded refrigerant is completed. .

  As described above, the suction and discharge of the refrigerant in the positive displacement mechanism (60) is determined by the rotation angle of the shaft (45). Therefore, the refrigerant suction flow rate and discharge flow rate in the expansion mechanism (60) are intermittent throughout the cycle. Therefore, pressure fluctuations (pressure pulsation) of the suction refrigerant and the discharge refrigerant occur in the inflow port (32) and the outflow port (33) of the expansion mechanism (60). This pressure fluctuation causes vibration of the entire device. Furthermore, since the expanded refrigerant is in a gas-liquid two-phase state at the outflow port (33) of the expansion mechanism (60), vibration is also generated when the refrigerant of the liquid droplet collides with the inner wall of the pipe. To do. Thus, a larger vibration is generated on the outlet side of the expansion mechanism (60) than on the inlet side.

  Therefore, the operation of the pressure buffering means (70) will be described. When the pressure fluctuation of the discharged refrigerant occurs, pressure supply and pressure absorption are performed by the buffer container (71).

  For example, when the flow rate of the discharged refrigerant at the outflow port (33) decreases and the refrigerant pressure decreases, a larger amount of refrigerant flows from the buffer container (71) to the connection pipe (P). Thereby, the pressure drop of the refrigerant | coolant in a connection pipe (P) is suppressed. Further, when the flow rate of the discharged refrigerant at the outflow port (33) increases and the refrigerant pressure rises, the increased amount of the refrigerant flowing into the buffer container (71) is stored in the buffer container (71) as it is. The remaining refrigerant flows out to the connecting pipe (P). Thereby, the pressure rise of the refrigerant | coolant in a connection pipe (P) is suppressed. That is, the buffer container (71) discharges and absorbs the refrigerant in accordance with the pressure fluctuation at the outflow port (33), so that the flow rate of the refrigerant in the connection pipe (P) is always kept constant.

  Further, the refrigerant flowing into the buffer container (71) from the outflow port (33) passes through the mesh portion (75a) of the rectifying plate (75), and the flow is stabilized. Therefore, the refrigerant of the liquid droplet does not collide with the pipe wall so vigorously. Further, when the refrigerant passes through the mesh portion (75a), the droplet refrigerant is miniaturized, so that even if the droplet refrigerant collides with the pipe wall, the impact is reduced.

  As described above, as shown in FIG. 5 (A), the refrigerant pressure fluctuation in the outlet side piping of the expansion mechanism (60) is compared with the case where the conventional buffer container (71) is not provided (see FIG. 11 (A)). It can be seen that it is significantly smaller. Furthermore, as shown in FIG. 5 (B), the vibration in the outlet side piping of the expansion mechanism (60) is smaller as a whole because there is no high-amplitude portion compared to the conventional case (see FIG. 11 (B)). I understand that.

-Effect of Embodiment 1-
As described above, according to the first embodiment, the buffer that is formed larger than the cross-sectional area of the outflow port (33) of the expansion mechanism (60) and relaxes the pressure fluctuation of the refrigerant discharged from the expansion mechanism (60). Since the container (71) is provided in the middle of the outlet side piping of the expansion mechanism (60), the pressure fluctuation of the refrigerant discharged from the expansion mechanism (60) can be reliably suppressed, and the vibration of the entire device due to the pressure fluctuation Can be suppressed.

  Furthermore, since the flow straightening plate (75) is provided in the buffer container (71), the flow of the refrigerant flowing into the buffer container (71) can be stabilized, and the droplets contained in the refrigerant can be stabilized. The refrigerant can be made finer. Thereby, it can suppress that the refrigerant | coolant of a droplet violently collides with a piping wall etc., and even if it collides, since the droplet is small, the impact can be relieved. Therefore, since the vibration generated when the liquid refrigerant collides with the piping wall or the like can be suppressed, the vibration of the entire device can be further suppressed in combination with the effects described above. As a result, there is no risk of damage to the devices.

  Moreover, since the pressure fluctuation of the discharged refrigerant in the expansion mechanism (60) is suppressed, the discharge pressure loss can be suppressed, the efficiency of the positive displacement expander (60) can be prevented from being lowered, Noise due to various pressure fluctuations can be prevented.

  Further, since the buffer container (71) is formed in a cylindrical shape extending along the refrigerant flow, for example, the flow resistance of the refrigerant is reduced as compared with a case where the buffer container (71) extends in a direction perpendicular to the refrigerant flow. be able to. Therefore, it is possible to suppress a decrease in operating efficiency due to the provision of the flow path expanding portion (71).

  Moreover, since carbon dioxide is used as the refrigerant in the refrigerant circuit (20), a device that is friendly to the global environment can be provided. In particular, in the case of carbon dioxide, since it is compressed to a critical pressure state, the pressure fluctuation increases accordingly, but this pressure pulsation can be reliably reduced.

-Modification of Embodiment 1-
A modification of the first embodiment will be described with reference to FIG. In this modification, the configuration of the rectifying plate (75) of the buffer container (71) in the first embodiment is changed. That is, instead of the first embodiment in which the rectifying plate (75) is formed in a mesh shape, the present modification forms a small hole (76a) that is a through hole over the entire surface of the rectifying plate (76). (See FIG. 6B). Note that FIG. 6B illustrates a cross section taken along line XX in FIG.

  In this case, the refrigerant flowing into the buffer container (71) flows through the small hole (76a) of the rectifying plate (76), so that the refrigerant flow is stabilized. Furthermore, when the refrigerant passes through the small hole (76a), the flow velocity becomes faster, and the droplet refrigerant is refined by the momentum. Therefore, similarly to the first embodiment, it is possible to suppress the vibration generated when the coolant of the droplet collides with the piping wall or the like. Other configurations, operations, and effects are the same as those of the first embodiment.

<< Embodiment 2 of the Invention >>
Next, Embodiment 2 of the present invention will be described with reference to FIG.

  In the second embodiment, a partition plate (77) is provided in the buffer container (71) instead of the current plate (75) provided in the buffer container (71) in the first embodiment. is there. Specifically, the partition plate (77) is formed in a disc shape, and has an outer diameter that is substantially the same as the inner diameter of the body (72) of the buffer container (71). At the center of the partition plate (77), one circular through hole (77a) is formed as a refrigerant circulation hole. The through hole (77a) has an inner diameter that is substantially the same as the inner diameter of the outflow port (33). The partition plate (77) is provided in the center of the interior of the buffer container (71), and the interior is divided into an upstream space on the outflow port (33) side and a downstream space on the connection pipe (P) side. Partitioning. That is, the inside of the buffer container (71) is constituted by two pressure buffer spaces.

  In this case, for example, when the pressure of the refrigerant discharged from the expansion mechanism (60) decreases, the refrigerant flows from the upstream space to the downstream space and flows out to the connecting pipe (P) together with the refrigerant in the downstream space. Conversely, when the pressure of the refrigerant discharged from the expansion mechanism (60) rises, the increased amount of refrigerant flows from the outflow port (33) to the upstream space, and part of it flows to the downstream space. That is, in the buffer container (71), the pressure fluctuation of the discharged refrigerant is reduced in two stages. Thereby, the impact accompanying sudden pressure fluctuation can be relieved. Therefore, the vibration of the entire device can be suppressed. Other configurations, operations, and effects are the same as those of the first embodiment.

  The number of partition plates (77) is not limited to this, and a plurality of partition plates (77) may be provided to form a plurality of pressure buffering spaces. For example, as shown in FIG. 8, three partition plates (77) may be provided to provide four pressure buffering spaces. In this case, the pressure fluctuation of the refrigerant discharged from the expansion mechanism (60) is relaxed in four stages. Therefore, the occurrence of vibration can be further suppressed.

<< Embodiment 3 of the Invention >>
Next, Embodiment 3 of the present invention will be described with reference to FIG.

  In the third embodiment, the current plate (75) of the first embodiment and the partition plate (77) of the second embodiment are provided one by one in the buffer container (71). Specifically, the partition plate (77) and the rectifying plate (76) are provided in this order from the outflow port (33) side. That is, in the buffer container (71), the inside is partitioned into two pressure buffering spaces, and the rectifying plate (75) is provided in the pressure buffering space on the downstream side thereof. Therefore, it is possible to suppress vibration due to pressure fluctuation, vibration due to collision of droplet refrigerant with the piping wall, and vibration due to sudden pressure fluctuation impact. The position of the partition plate (77) and the rectifying plate (75) may be interchanged with each other, or the rectifying plate used in the modification of the first embodiment instead of the mesh-like rectifying plate (75). Of course, (76) may be used. Other configurations, operations, and effects are the same as those of the first embodiment.

-Modification of Embodiment 3-
A modification of the third embodiment will be described with reference to FIG. In this modified example, the buffer container (71) is used in a state where the buffer container (71) is raised vertically, instead of using the buffer container (71) in a state where the buffer container (71) is tilted horizontally. That is, in Embodiment 3 above, the refrigerant that has flowed into the buffer container (71) flows in the horizontal direction, but in this modification, the refrigerant flows in the vertical direction.

  Specifically, the buffer container (71) is arranged such that the body part (72) extends in the vertical direction, and the upper end surface of the body part (72) is closed by the inlet side end part (73), and the lower side The end face is closed by the outlet side end (74). That is, the buffer container (71) is formed in a cylindrical container extending in the vertical direction. The outflow port (33) is connected to the upper part of the body part (72) which is the upper side surface of the buffer container (71), and the connection pipe (P) is the outlet side end part (the lower surface of the buffer container (71) ( 74) is connected to the center.

  In the buffer container (71), the refrigerant flowing in from the outflow port (33) flows vertically downward. That is, not only the inflowing gas refrigerant but also the liquid refrigerant flows from top to bottom and flows out to the connecting pipe (P). Therefore, the liquid refrigerant can be prevented from accumulating in the buffer container (71). The outflow port (35) may be connected to the inlet end (73) which is the upper surface of the buffer container (71). Other configurations, operations, and effects are the same as those of the first embodiment.

<< Other Embodiments >>
For example, the shape of the current plate (75, 76) in each of the above embodiments is not limited to this. In other words, the cross-sectional shape of the rectifying plate (75, 76) may be formed in a circular shape or a polygonal shape having an area that substantially occupies the transverse cross section of the buffer container (71).

  Further, the number of the rectifying plates (75) is not limited to one, and two or more rectifying plates (75) may be provided adjacent to each other in parallel.

  Further, the shape of the buffer container (71) is not limited to a cylindrical shape. That is, the buffer container (71) may be formed in a cylindrical shape with a rectangular cross-sectional view extending along the refrigerant flow direction, or a so-called gradual increase in the cross-sectional area of the refrigerant flow path from the inlet side toward the outlet side. You may form in an expanded tube.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful as a refrigeration apparatus including a refrigerant circuit having a positive displacement expander.

It is a piping system diagram showing an air conditioner according to an embodiment. The principal part of the expansion mechanism which concerns on embodiment is shown, (A) is a cross-sectional view, (B) is a longitudinal cross-sectional view. The buffer container which concerns on Embodiment 1 is shown, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view. It is a cross-sectional view showing the operating state of the expansion mechanism according to the embodiment. (A) is a characteristic view which shows the flow velocity and pressure of the discharge refrigerant | coolant of an expansion mechanism, (B) is a characteristic view which shows the magnitude | size of the vibration generate | occur | produced in the exit side of an expansion mechanism. The buffer container which concerns on the modification of Embodiment 1 is shown, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view. The buffer container which concerns on Embodiment 2 is shown, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view. 10 is a longitudinal sectional view showing a buffer container according to a modification of the second embodiment. FIG. 6 is a longitudinal sectional view showing a buffer container according to Embodiment 3. FIG. 10 is a longitudinal sectional view showing a buffer container according to a modification of Embodiment 3. FIG. (A) is a characteristic view which shows the flow velocity and pressure of the discharge refrigerant | coolant of the conventional expansion mechanism, (B) is a characteristic view which shows the magnitude | size of the vibration generate | occur | produced in the exit side of the conventional expansion mechanism.

Explanation of symbols

10 Air conditioner (refrigeration equipment)
20 Refrigerant circuit
60 Expansion mechanism (positive displacement expander)
71 Buffer container (channel expansion part)
75,76 Rectifying plate (rectifying means)
77 divider

Claims (8)

A refrigerating apparatus comprising a refrigerant circuit (20) connected to a positive displacement expander (60) and performing a vapor compression refrigeration cycle,
The refrigerant circuit (20) is a refrigerant that is formed in the middle of the outlet side pipe of the positive displacement expander (60) and has a refrigerant cross-sectional area larger than that of the outlet side pipe and flows out of the positive displacement expander (60). A refrigeration apparatus comprising a flow path enlargement section (71) that relieves pressure fluctuations. A refrigerating apparatus comprising a refrigerant circuit (20) connected to a positive displacement expander (60) and performing a vapor compression refrigeration cycle,
The refrigerant circuit (20) is formed in a cylindrical shape extending in the refrigerant flow direction in the middle of the outlet side pipe of the positive displacement expander (60) and having a refrigerant cross-sectional area larger than that of the outlet side pipe. A refrigeration apparatus comprising a flow path enlargement section (71). In claim 2,
The flow path enlargement part (71) is arranged in a state extending in the vertical direction, and is arranged on the outlet side pipe of the positive displacement expander (60) so that the refrigerant flowing from the upper part flows vertically downward and flows out from the lower surface. A refrigeration apparatus characterized by being connected. In any one of Claims 1 thru | or 3,
A refrigerating apparatus characterized in that a refrigerant rectifying means (75, 76) is provided inside the flow path expanding section (71). In claim 4,
The rectifying means (76) is a refrigeration apparatus which is formed in a plate shape having a plurality of through holes and is provided to face the refrigerant in the flow direction. In claim 4,
The rectifying device (75) is a refrigeration apparatus formed of a plate-shaped mesh member and a rectifying plate provided to face the refrigerant in the flow direction. In any one of Claims 2 thru | or 4,
The refrigerating apparatus according to claim 1, wherein the flow path expanding portion (71) is provided with a partition plate (77) having a through hole and partitioning the inside in a flow direction of the refrigerant. In claim 1 or 2,
The refrigeration apparatus, wherein the refrigerant is carbon dioxide.

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