FLOW SWITCHING DEVICE AND REFRIGERATION CYCLE APPARATUS INCLUDING THE SAME

TECHNICAL FIELD

The present disclosure relates to a flow switching device and a refrigeration cycle apparatus including the same.

BACKGROUND

In the past, a check-valve unit has been proposed that serves as a bridge circuit formed of four check valves, the directions of the refrigerant flow are switched with the switching of the operation mode between a cooling operation and a heating operation, but is constant in a certain section of the refrigerant circuit (see Patent Literature 1, for example). The check-valve unit disclosed by Patent Literature 1 includes four valve bodies that are mechanically movable up and down to control the refrigerant flow.

PATENT LITERATURE

- Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2018-119577

The valve bodies of the check-valve unit disclosed by Patent Literature 1 includes movable elements that are mechanically movable. Therefore, noise may occur with sliding motions of the valve bodies.

SUMMARY

The present disclosure is to solve the above problem and provides a flow switching device that ensures a check-valve function with reduced noise, and a refrigeration cycle apparatus including the same.

A flow switching device according to an embodiment of the present disclosure is provided at a refrigeration cycle apparatus. The flow switching device includes a plurality of plates; and a first inlet, a second inlet and a flow passage connecting between the first inlet and the second inlet. The flow passage have an anisotropic flow passage configured to have a forward flow resistance for a forward flow, the forward flow being a refrigerant flow from the first inlet to the second inlet, and a backward flow resistance for an inverse flow, the inverse flow being a refrigerant flow from the second inlet to the first inlet, the forward flow resistance being different from the backward flow resistance. A part of the anisotropic flow passage is at a plate, on which neither the first inlet nor the second the inlet is formed, of the plurality of plates.

A refrigeration cycle apparatus according to another embodiment of the present disclosure includes a refrigerant circuit including a heat exchanger, and the above flow switching device included in the refrigerant circuit.

According to the above embodiments of the present disclosure, the anisotropic flow passage, serving as a check valve, is divided into separate parts provided at respective plates, whereby the check-valve function is ensured. Thus, automatic switching of the directions of the refrigerant flow is enabled. Since the flow switching device includes no movable elements such as valve bodies, the occurrence of noise that may be generated by any sliding motions is prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view of a flow switching device according to Embodiment 1, illustrating an exemplary configuration thereof.

FIG. 2 is a plan view of a first plate, illustrated in FIG. 1.

FIG. 3 is an enlarged view of an anisotropic flow passage, illustrated in FIG. 2.

FIG. 4 schematically illustrates how refrigerant flows in the forward direction in the flow switching device illustrated in FIG. 1.

FIG. 5 schematically illustrates how refrigerant flows in the inverse direction in the flow switching device illustrated in FIG. 1.

FIG. 6 is a refrigerant circuit diagram illustrating an exemplary configuration of a refrigeration cycle apparatus including the flow switching device illustrated in FIG. 1.

FIG. 7 is an exploded perspective view of a flow switching device according to Embodiment 2, illustrating an exemplary configuration thereof.

FIG. 8 is a plan view of a first plate, illustrated in FIG. 7.

FIG. 9 illustrates an exemplary configuration in which the flow switching device illustrated in FIG. 7 is provided in a refrigeration cycle apparatus.

FIG. 10 is an exploded perspective view of a flow switching device according to Embodiment 3, illustrating an exemplary configuration thereof.

FIG. 11 is a plan view of a first plate, illustrated in FIG. 10.

FIG. 12 illustrates how refrigerant flows through the flow switching device illustrated in FIG. 10 when the refrigerant is received at a fourth inlet and is discharged from a third inlet.

FIG. 13 illustrates how refrigerant flows through the flow switching device illustrated in FIG. 10 when the refrigerant is received at the third inlet and is discharged from the fourth inlet.

FIG. 14 is a plan view of a first plate according to Modification 1 included in the flow switching device according to Embodiment 3, illustrating an exemplary configuration thereof.

FIG. 15 is a see-through diagram for describing a configuration of a flow switching device according to Embodiment 4.

FIG. 16 is an exploded perspective view of the flow switching device according to Embodiment 4, illustrating an exemplary configuration thereof.

FIG. 17 is a plan view of a first flow-passage plate and a second flow-passage plate, illustrated in FIG. 16.

FIG. 18 is a see-through diagram for describing a configuration of a flow switching device according to Modification 2 of Embodiment 3.

FIG. 19 is an exploded perspective view of the flow switching device according to Modification 2, illustrating an exemplary configuration thereof.

FIG. 20 is a plan view of a first flow-passage plate and a second flow-passage plate, illustrated in FIG. 19.

FIG. 21 is a refrigerant circuit diagram illustrating an exemplary configuration of a refrigeration cycle apparatus according to Embodiment 5.

FIG. 22 illustrates the direction of a refrigerant flow generated in the flow switching device when the refrigeration cycle apparatus illustrated in FIG. 21 is in a cooling operation.

FIG. 23 illustrates the direction of a refrigerant flow generated when the refrigeration cycle apparatus illustrated in FIG. 21 is in a heating operation.

FIG. 24 illustrates the direction of the refrigerant flow generated in the flow switching device when the refrigeration cycle apparatus illustrated in FIG. 21 is in the heating operation.

FIG. 25 is a perspective view of a heat-source-side heat exchanger having an exemplary counterflow configuration.

FIG. 26 illustrates exemplary air-temperature distributions in the heat-source-side heat exchanger illustrated in FIG. 25 that is operating as an evaporator.

DETAILED DESCRIPTION

Flow switching devices according to embodiments will now be described with reference to the drawings. As a matter of convenience of description, some of the drawings are provided with arrows representing three axes (an X axis, a Y axis, and a Z axis) for defining directions.

Embodiment 1

A flow switching device according to Embodiment 1 is configured as follows. FIG. 1 is an exploded perspective view of a flow switching device according to Embodiment 1, illustrating an exemplary configuration thereof. The flow switching device 1, is configured as a stack of a first plate 2a and a second plate 2b. The first plate 2a has a flow passage 3, which is in the form of a groove. The flow passage 3 is parallel to the surfaces of the first plate 2a and the second plate 2b that are stacked. The second plate 2b has a first inlet 11 and a second inlet 12, which each serve as an inlet for refrigerant. Placing the second plate 2b on the first plate 2a defines the flow passage 3. The flow passage 3 has two ends 3a and 3b. The end 3a faces the first inlet 11. The end 3b faces the second inlet 12.

FIG. 2 is a plan view of the first plate illustrated in FIG. 1. The flow passage 3 includes a plurality of anisotropic flow passages 5. The first plate 2a illustrated in FIG. 1 has an exemplary configuration with six anisotropic flow passages 5. The first plate 2a may have only one anisotropic flow passage 5. In FIG. 2, the outlines of the first inlet 11 and the second inlet 12 illustrated in FIG. 1 are represented by broken lines. As illustrated in FIGS. 1 and 2, the plurality of anisotropic flow passages 5 are connected in series to form a continuous flow passage, which is referred to as anisotropic-flow-passage row.

In the flow passage 3 illustrated in FIG. 2, the direction from the first inlet 11 to the second inlet 12 is the forward direction, and the direction from the second inlet 12 to the first inlet 11 is the inverse direction. Each anisotropic flow passage 5 is configured to have a forward flow resistance for a forward flow, and a backward flow resistance for an inverse flow. The forward flow resistance is different from the backward flow resistance. The anisotropic flow passage 5 is characterized in that the backward flow resistance is greater than the forward flow resistance.

FIG. 3 is an enlarged view of the anisotropic flow passage illustrated in FIG. 2. The anisotropic flow passage 5 includes a main flow passage 7 and a subsidiary flow passage 8. The main flow passage 7 is configured to receive some of refrigerant flowing from the first inlet 11. The subsidiary flow passage 8 is configured to receive a remaining portion of the refrigerant flowing from the first inlet 11 excluding the some of the refrigerant. The subsidiary flow passage 8 causes the remaining portion of the refrigerant to merge with the some of the refrigerant flowing in the main flow passage 7. The arrows illustrated in FIG. 3 applies to the forward refrigerant flow.

As illustrated in FIG. 3, the main flow passage 7 includes a main first linear part 7a and a main second linear part 7b, which are linear. The main second linear part 7b is aligned with the main first linear part 7a on a single straight line. FIG. 3 illustrates an exemplary configuration in which the main first linear part 7a and the main second linear part 7b are continuous with each other. The subsidiary flow passage 8 has a U shape. The subsidiary flow passage 8 includes a subsidiary first linear part 8a, which is linear; a subsidiary second linear part 8b, which is longer than the subsidiary first linear part 8a; and a curved part 8c, which is curved in a U shape. The subsidiary first linear part 8a and the subsidiary second linear part 8b are parallel to each other.

The main flow passage 7 and the subsidiary flow passage 8 are connected to each other at a first merging point 9a and at a second merging point 9b. One of the two ends of the subsidiary first linear part 8a is connected to the main first linear part 7a at the first merging point 9a, while the other end is connected to the curved part 8c. One of the two ends of the subsidiary second linear part 8b is connected to the main second linear part 7b at the second merging point 9b, while the other end is connected to the curved part 8c.

Letting the angle formed at the first merging point 9a between a straight line parallel to the main first linear part 7a and a straight line parallel to the subsidiary first linear part 8a be ea, the angle θa is an acute angle. Letting the angle formed at the second merging point 9b between a straight line parallel to the main second linear part 7b and a straight line parallel to the subsidiary second linear part 8b be Ob, the angle θb is an acute angle. In the exemplary configuration illustrated in FIG. 3, the angle θa and the angle θb are in a relationship of θa=θb.

In the anisotropic flow passage 5 illustrated in FIG. 3, when refrigerant flows in the inverse direction from the second inlet 12 to the first inlet 11, the refrigerant splits at the second merging point 9b into a refrigerant portion received by the main flow passage 7 and a refrigerant portion received by the subsidiary flow passage 8. Then, the refrigerant portion flowing through the subsidiary flow passage 8 merges with the refrigerant portion flowing through the main flow passage 7 at the first merging point 9a, where the refrigerant portion in the subsidiary flow passage 8 forms the acute angle θa relative to the flow of the refrigerant portion in the main flow passage 7. Therefore, at the first merging point 9a, the flow of the refrigerant portion in the main flow passage 7 is hindered by the flow of the refrigerant portion in the subsidiary flow passage 8. Consequently, in the anisotropic flow passage 5, the backward flow resistance becomes greater than the forward flow resistance. Thus, the anisotropic flow passage 5 has a Tesla-valve structure, in which the flow resistance is anisotropic and the refrigerant has far greater difficulty in flowing in the inverse direction than in the forward direction.

The flow passage 3 illustrated in FIG. 2 includes six anisotropic flow passages 5 connected to one another and each configured as illustrated in FIG. 3. Focusing on two anisotropic flow passages 5 that are adjacent to each other in the direction of the Y-axis arrow provided in FIG. 2, each of the two adjacent anisotropic flow passages 5 is the mirror inversion of the other. For example, in FIG. 3, defining one of the anisotropic flow passages 5 that is closest to the first inlet 11 as the first anisotropic flow passage 5, the second anisotropic flow passage 5 connected to the first anisotropic flow passage 5 is shaped as a mirror inversion of the anisotropic flow passage 5 illustrated in FIG. 3. Specifically, the upper end of the main flow passage 7 of the second anisotropic flow passage 5 is connected to the second merging point 9b of the first anisotropic flow passage 5, so that the main flow passage 7 of the second anisotropic flow passage 5 lies on the extension of the subsidiary second linear part 8b of the first anisotropic flow passage 5.

While FIG. 3 illustrates a case where the angles θa and θb are in a relationship of θa=θb, the angles θa and θb may be in a relationship of θa≠θb. One or both of the angles θa and θb may be set appropriately in such a manner as to meet the design specifications for the backward flow resistance.

While FIG. 1 illustrates a case where the first inlet 11 and the second inlet 12 are provided in the second plate 2b that is placed on the upper surface (the surface facing in the direction of the Z-axis arrow) of the first plate 2a, one of the two inlets may be provided in another plate. For example, an additional plate (not illustrated) may be placed on the lower surface (the surface facing in the opposite direction of the Z-axis arrow) of the first plate 2a, and the second inlet 12 may be provided in the additional plate at a position facing the end 3b. In such a case, the first plate 2a has a through-hole at the end 3b, whereas the second plate 2b has no second inlet 12.

Now, how the flow switching device 1 illustrated in FIG. 1 works will be described with reference to FIGS. 4 and 5. FIG. 4 schematically illustrates how refrigerant flows in the forward direction in the flow switching device illustrated in FIG. 1. FIG. 5 schematically illustrates how refrigerant flows in the inverse direction in the flow switching device illustrated in FIG. 1.

In the forward flow illustrated in FIG. 4, an inertial force exerted by the refrigerant flowing from the first inlet 11 increases the amount of the refrigerant portion to be received by the main flow passage 7. Consequently, the amount of the refrigerant portion to be received by the subsidiary flow passage 8 becomes smaller than the amount of the refrigerant portion to be received by the main flow passage 7. The refrigerant portion in the subsidiary flow passage 8 smoothly merges with the refrigerant portion in the main flow passage 7 by flowing along the refrigerant portion in the main flow passage 7. Therefore, at the merging point between the main flow passage 7 and the subsidiary flow passage 8, the refrigerant portion flowing out of the subsidiary flow passage 8 into the main flow passage 7 does not act as a large flow resistance to the refrigerant portion flowing in the main flow passage 7.

In the inverse flow illustrated in FIG. 5, the amount of the refrigerant portion to be received by the main flow passage 7 and the amount of the refrigerant portion to be received by the subsidiary flow passage 8 are about the same. The refrigerant portion in the subsidiary flow passage 8 flows against the refrigerant portion in the main flow passage 7 when merging therewith and therefore generates a vortex, which acts as a large flow resistance. Thus, the flow switching device 1 has a Tesla-valve characteristic in which refrigerant flows smoothly in the forward direction but not smoothly in the inverse direction.

The flow switching device 1 illustrated in FIG. 1 is manufactured as follows. The first plate 2a is processed with a laser, whereby a groove serving as a flow passage 3 is provided in the first plate 2a. The second plate 2b is processed with a press, whereby a first inlet 11 and a second inlet 12 are provided in the second plate 2b. The second plate 2b is placed on the first plate 2a, and the two plates are fixed to each other. The second plate 2b serves as a lid plate that prevents the leakage of refrigerant that is made to flow between the first inlet 11 and the second inlet 12.

A refrigeration cycle apparatus that includes the flow switching device illustrated in FIG. 1 is configured as follows. FIG. 6 is a refrigerant circuit diagram illustrating an exemplary configuration of a refrigeration cycle apparatus including the flow switching device illustrated in FIG. 1.

The refrigeration cycle apparatus, 30, includes a compressor 31, a condenser 32, an expansion valve 33, and a cooler 34. The cooler 34 serves as an evaporator. The compressor 31, the condenser 32, the expansion valve 33, and the cooler 34 are connected to one another by refrigerant pipes, whereby a refrigerant circuit 40 is formed through which refrigerant is made to circulate. On the refrigerant-suction side of the compressor 31 is provided an accumulator 35. On the refrigerant-discharge side of the compressor 31 is provided a four-way valve 36. The four-way valve 36 is connected to the refrigerant discharge port of the compressor 31, to the accumulator 35, to the condenser 32, and to the cooler 34. The condenser 32, the expansion valve 33, and the cooler 34 are connected to one another by a refrigerant pipe 38. The refrigerant pipe 38 is provided with a drier 37 at a position between the condenser 32 and the expansion valve 33. In parallel with the expansion valve 33 and the drier 37 is provided a bypass circuit 39. The bypass circuit 39 includes a capillary tube 41 and a check valve 42. The check valve 42 corresponds to the flow switching device 1 illustrated in FIG. 1.

Referring to FIG. 6, how the refrigeration cycle apparatus 30 operates will now be described. Note that the following description mainly relates to the function of the check valve 42, and detailed description of a basic operation of the refrigeration cycle circuit is omitted. In FIG. 6, a refrigerant flow generated when the refrigeration cycle apparatus 30 is in an air-cooling operation is represented by solid-line arrows, and a refrigerant flow generated when the refrigeration cycle apparatus 30 is in a defrosting operation is represented by broken-line arrows.

The air-cooling operation of the refrigeration cycle apparatus 30 is as follows. Refrigerant is discharged from the compressor 31 and flows through the four-way valve 36 into the condenser 32. The refrigerant having reached the condenser 32 exchanges heat with air and flows into the refrigerant pipe 38 but does not flow into the bypass circuit 39 because this refrigerant flow is inverse for the check valve 42. The refrigerant having flowed into the refrigerant pipe 38 flows through the drier 37, is expanded by the expansion valve 33, and flows into the cooler 34. The refrigerant having reached the cooler 34 exchanges heat with air in an air-conditioning target space, whereby the air in the air-conditioning target space is cooled. The refrigerant discharged from the cooler 34 flows through the four-way valve 36 into the accumulator 35 and returns into the compressor 31.

The defrosting operation of the refrigeration cycle apparatus 30 is as follows. During the defrosting operation of the refrigeration cycle apparatus 30, the expansion valve 33 is kept closed. High-temperature refrigerant is discharged from the compressor 31 and flows through the four-way valve 36 into the cooler 34. The refrigerant having reached the cooler 34 melts the frost generated on the cooler 34 and then flows into the bypass circuit 39 because the expansion valve 33 is closed. The refrigerant flows through the capillary tube 41 and then flows through the check valve 42 because this refrigerant flow is forward for the check valve 42. The refrigerant discharged from the check valve 42 flows into the condenser 32. The refrigerant discharged from the condenser 32 flows through the four-way valve 36 into the accumulator 35 and returns into the compressor 31. Thus, the refrigerant flow is controlled by the check valve 42 in correspondence with the operation mode of the refrigeration cycle apparatus 30 that is switchable between the air-cooling operation and the defrosting operation.

The flow switching device 1 according to Embodiment 1 includes the plurality of plates; and the first inlet, the second inlet and the flow passage 3 connecting between the first inlet 11 and the second inlet 12. The flow passage 3 has the anisotropic flow passage 5. The anisotropic flow passage 5 is configured to have a forward flow resistance for a forward flow and a backward flow resistance for an inverse flow. The forward flow is a refrigerant flow from the first inlet 11 to the second inlet 12. The inverse flow is a refrigerant flow from the second inlet 12 to the first inlet 11. The forward flow resistance is different from the backward flow resistance. The anisotropic flow passage 5 is at a plate, on which neither the first inlet 11 nor the second the inlet 12 is formed, of the plurality of plates.

Embodiment 1 employs an anisotropic flow passage that serves as a check valve. Therefore, the directions of the refrigerant flow are automatically switchable with no movable elements such as valve bodies. The flow switching device 1 including no such movable elements generates no noise that may be generated by any sliding motions. Therefore, noise due to any movable elements is reduced. Furthermore, the flow switching device 1 including no movable elements is free from wear of valve bodies due to chattering. Furthermore, the flow switching device 1 including no movable elements is free from clogging with foreign matter that may occur in movable elements and is also free from malfunctioning of the check valve due to clogging.

In Embodiment 1, a plurality of anisotropic flow passages 5 are provided in a single plate member. Providing a plurality of anisotropic flow passages 5 in a single plate member not only provides the function of a plurality of check valves but also suppresses the increase in the size of the space to be secured for the plurality of check valves.

Embodiment 2

Embodiment 2 relates to a configuration with a plurality of anisotropic-flow-passage rows, each described in Embodiment 1. Embodiment 2 employs a configuration with two anisotropic-flow-passage rows. In Embodiment 2, elements that are the same as those described in Embodiment 1 are denoted by corresponding ones of the reference signs, and detailed description of such elements is omitted.

A flow switching device according to Embodiment 2 is configured as follows. FIG. 7 is an exploded perspective view of a flow switching device according to Embodiment 2, illustrating an exemplary configuration thereof. The flow switching device, 1a, is configured as a stack of a first plate 20a and a second plate 20b.

The first plate 20a has a first anisotropic-flow-passage row 6a and a second anisotropic-flow-passage row 6b, which are each in the form of a groove. The second plate 20b has a first inlet 11, a second inlet 12, a third inlet 13, and a fourth inlet 14, which each serve as an inlet for refrigerant. Placing the second plate 20b on the first plate 20a defines the first anisotropic-flow-passage row 6a and the second anisotropic-flow-passage row 6b.

FIG. 8 is a plan view of the first plate illustrated in FIG. 7. In FIG. 8, the outlines of the first to fourth inlets 11 to 14 illustrated in FIG. 1 are represented by broken lines.

In the first anisotropic-flow-passage row 6a, a refrigerant flow from the first inlet 11 to the second inlet 12 is the forward flow, whereas a refrigerant flow from the second inlet 12 to the first inlet 11 is the inverse flow. In the second anisotropic-flow-passage row 6b, a refrigerant flow from the fourth inlet 14 to the third inlet 13 is the forward flow, whereas a refrigerant flow from the third inlet 13 to the fourth inlet 14 is the inverse flow. The first anisotropic-flow-passage row 6a and the second anisotropic-flow-passage row 6b are arranged in parallel and such that the forward direction for the first anisotropic-flow-passage row 6a and the forward direction for the second anisotropic-flow-passage row 6b are opposite to each other.

Now, how the flow switching device 1a according to Embodiment 2 works will be described with reference to FIG. 9. FIG. 9 illustrates an exemplary configuration in which the flow switching device illustrated in FIG. 7 is provided in a refrigeration cycle apparatus. The following description relates to a case of a refrigeration cycle apparatus including the flow switching device 1a in which, for example, a cooling operation and a heating operation are switchable therebetween by a four-way valve that is capable of switching the directions of the refrigerant flow.

As illustrated in FIG. 9, the flow switching device 1a is connected to a heat-source-side heat exchanger 45. The heat-source-side heat exchanger 45 is connected to a refrigerant pipe 46. The flow switching device 1a is connected to a refrigerant pipe 47. The refrigerant pipe 46 and the refrigerant pipe 47 are connected to a compressor, a load-side heat exchanger, and an expansion valve, which are all not illustrated. The heat-source-side heat exchanger 45 includes a heating heat exchanger 45a and a cooling heat exchanger 45b. The heating heat exchanger 45a is connected to the first anisotropic-flow-passage row 6a. The cooling heat exchanger 45b is connected to the second anisotropic-flow-passage row 6b. The heating heat exchanger 45a is designed to increase in the heating operation the heat-exchanger effectiveness of the refrigeration cycle circuit. The cooling heat exchanger 45b is designed to increase in the cooling operation the heat-exchanger effectiveness of the refrigeration cycle circuit.

In the heating operation of the refrigeration cycle apparatus, refrigerant flows from the refrigerant pipe 46 into the heat-source-side heat exchanger 45. Accordingly, the flow of the refrigerant into the heat-source-side heat exchanger 45 is inverse for the second anisotropic-flow-passage row 6b connected to the cooling heat exchanger 45b. Therefore, the refrigerant flows into the heating heat exchanger 45a. In the cooling operation of the refrigeration cycle apparatus, refrigerant flows from the refrigerant pipe 47 into the flow switching device 1a. Accordingly, the flow of the refrigerant into the flow switching device 1a is inverse for the first anisotropic-flow-passage row 6a. Therefore, the refrigerant flows into the cooling heat exchanger 45b through the second anisotropic-flow-passage row 6b, for which the refrigerant flow is forward. In FIG. 9, the refrigerant flows generated in the heating operation and the cooling operation are represented by respective arrows.

In many refrigeration cycle apparatuses, the specifications of the heat exchangers are different between different operation modes so that an increased heat-exchanger effectiveness is exerted in the individual operation modes of a cooling operation and a heating operation. In view of such circumstances, the flow switching device 1a is provided in the refrigerant circuit of such a refrigeration cycle apparatus, as described above with reference to FIG. 9. Thus, the two different heat exchangers are automatically switchable therebetween for use at the switching of the directions of the refrigerant flow in the refrigerant circuit. That is, providing the flow switching device 1a in a refrigeration cycle apparatus including two different heat exchangers arranged in parallel in a refrigerant circuit enables the switching between the heat exchangers in correspondence with the switching of the operation modes between a cooling operation and a heating operation, whereby the heat-exchanger effectiveness is increased.

Furthermore, since the first anisotropic-flow-passage row 6a and the second anisotropic-flow-passage row 6b are arranged such that the forward directions thereof are opposite to each other, branches for splitting the refrigerant into respective portions for the first anisotropic-flow-passage row 6a and the second anisotropic-flow-passage row 6b can be arranged in parallel. Consequently, an extra space is provided for the refrigerant pipes.

While the above description given with reference to FIG. 9 relates to a case where a refrigerant device to be connected to the flow switching device 1a is the heat-source-side heat exchanger 45, the refrigerant device is not limited to the heat-source-side heat exchanger 45. The refrigerant device to be connected to the flow switching device 1a may alternatively be any other refrigerant device such as a load-side heat exchanger, an expansion valve, or a refrigerant container.

The flow switching device 1a illustrated in FIG. 7 is manufactured as follows. The first plate 20a is processed with a laser, whereby grooves serving as a first anisotropic-flow-passage row 6a and a second anisotropic-flow-passage row 6b are provided in the first plate 20a. The second plate 20b is processed with a press, whereby first to fourth inlets 11 to 14 are provided in the second plate 20b. The second plate 20b is placed on the first plate 20a, and the two plates are fixed to each other. The second plate 20b serves as a lid plate that prevents the leakage of refrigerant that is made to flow through the first anisotropic-flow-passage row 6a and the second anisotropic-flow-passage row 6b.

An advantageous effect of the flow switching device 1a according to Embodiment 2 is as follows. Among refrigeration cycle apparatuses in which a cooling operation and a heating operation are switchable therebetween by a four-way valve that is capable of switching the directions of the refrigerant flow, some employ refrigerant devices each being based on different specifications for different operation modes of the cooling operation and the heating operation. If the refrigerant circuit of such a refrigeration cycle apparatus includes the flow switching device 1a according to Embodiment 2, the refrigerant device to be supplied with refrigerant is automatically determined in correspondence with the operation mode, including the cooling operation and the heating operation, when the direction of the refrigerant flow in the refrigerant circuit is changed.

Embodiment 3

Embodiment 3 employs a configuration with four anisotropic-flow-passage rows. The following description of Embodiment 3 relates to a case where the four anisotropic-flow-passage rows form a bridge circuit. In Embodiment 3, elements that are the same as those described in Embodiment 1 or 2 are denoted by corresponding ones of the reference signs, and detailed description of such elements is omitted.

A flow switching device according to Embodiment 3 is configured as follows. FIG. 10 is an exploded perspective view of a flow switching device according to Embodiment 3, illustrating an exemplary configuration thereof. The flow switching device, 1b, is configured as a stack of a first plate 21a, a third plate 21c, and a second plate 21b. The third plate 21c is held between the first plate 21a and the second plate 21b.

The first plate 21a has a first anisotropic-flow-passage row 16a, a second anisotropic-flow-passage row 16b, a third anisotropic-flow-passage row 16c, and a fourth anisotropic-flow-passage row 16d, which are each in the form of a groove. The second plate 21b has a first inlet 11, a second inlet 12, a third inlet 13, and a fourth inlet 14, which each serve as an inlet for refrigerant. The third plate 21c has a first connecting flow passage 17, a first supplementary flow passage 18a, a second supplementary flow passage 18b, and a second connecting flow passage 19.

The first connecting flow passage 17 receives refrigerant from the first inlet 11 and discharges the refrigerant into the first anisotropic-flow-passage row 16a or the third anisotropic-flow-passage row 16c. The first supplementary flow passage 18a receives refrigerant from the third inlet 13 and discharges the refrigerant into the second anisotropic-flow-passage row 16b. Furthermore, the first supplementary flow passage 18a receives refrigerant from the first anisotropic-flow-passage row 16a and discharges the refrigerant into the third inlet 13. The second supplementary flow passage 18b receives refrigerant from the fourth inlet 14 and discharges the refrigerant into the fourth anisotropic-flow-passage row 16d. Furthermore, the second supplementary flow passage 18b receives refrigerant from the third anisotropic-flow-passage row 16c and discharges the refrigerant into the fourth inlet 14. The second connecting flow passage 19 receives the refrigerant from the second anisotropic-flow-passage row 16b and the fourth anisotropic-flow-passage row 16d and discharges the refrigerant.

FIG. 11 is a plan view of the first plate illustrated in FIG. 10. One end of the first anisotropic-flow-passage row 16a and one end of the third anisotropic-flow-passage row 16c are connected to the first inlet 11 through the first connecting flow passage 17. One end of the second anisotropic-flow-passage row 16b and one end of the fourth anisotropic-flow-passage row 16d are connected to the second inlet 12 through the second connecting flow passage 19. The other end of the first anisotropic-flow-passage row 16a and the other end of the second anisotropic-flow-passage row 16b are connected to the third inlet 13 through the first supplementary flow passage 18a. The other end of the third anisotropic-flow-passage row 16c and the other end of the fourth anisotropic-flow-passage row 16d are connected to the fourth inlet 14 through the second supplementary flow passage 18b.

In the first anisotropic-flow-passage row 16a, a refrigerant flow from the first inlet 11 to the third inlet 13 is the forward flow. In the second anisotropic-flow-passage row 16b, a refrigerant flow from the third inlet 13 to the second inlet 12 is the forward flow. In the third anisotropic-flow-passage row 16c, a refrigerant flow from the first inlet 11 to the fourth inlet 14 is the forward flow. In the fourth anisotropic-flow-passage row 16d, a refrigerant flow from the fourth inlet 14 to the second inlet 12 is the forward flow. Thus, the four rows of the anisotropic flow passages, namely the first anisotropic-flow-passage row 16a, the second anisotropic-flow-passage row 16b, the third anisotropic-flow-passage row 16c, and the fourth anisotropic-flow-passage row 16d, form a bridge circuit.

Referring to FIG. 11, the first anisotropic-flow-passage row 16a and the third anisotropic-flow-passage row 16c are parallel to each other, and the second anisotropic-flow-passage row 16b and the fourth anisotropic-flow-passage row 16d are parallel to each other. The first anisotropic-flow-passage row 16a and the third anisotropic-flow-passage row 16c are each oblique relative to the opposite direction of the Y-axis arrow. Specifically, the two anisotropic-flow-passage rows are each oblique relative to the opposite direction of the Y-axis arrow by the angle θb, illustrated in FIG. 3, in the opposite direction of the X-axis arrow while extending in the forward direction. Meanwhile, the other two anisotropic-flow-passage rows, namely the second anisotropic-flow-passage row 16b and the fourth anisotropic-flow-passage row 16d, are each oblique relative to the opposite direction of the Y-axis arrow by the angle θb in the direction of the X-axis arrow while extending in the forward direction.

In short, two of the anisotropic-flow-passage rows are oblique relative to the Y axis by the angle θb in the opposite direction of the X-axis arrow, whereas the other two anisotropic-flow-passage rows connected to the former two are oblique relative to the Y axis by the angle θb in the direction of the X-axis arrow. Such an arrangement of the four anisotropic-flow-passage rows with reference to the Y axis reduces the plan-view size of the first plate 21a in the widthwise (X-axis) direction orthogonal to the lengthwise (Y-axis) direction.

The first supplementary flow passage 18a extends parallel to the main flow passage 7, in the first anisotropic-flow-passage row 16a, of one of the anisotropic flow passages that is closest to the first supplementary flow passage 18a. The second supplementary flow passage 18b extends parallel to the main flow passage 7, in the third anisotropic-flow-passage row 16c, of one of the anisotropic flow passages that is closest to the second supplementary flow passage 18b. The first supplementary flow passage 18a and the second supplementary flow passage 18b extend obliquely toward the second inlet 12 located opposite the first inlet 11 (on the side opposite the side indicated by the Y-axis arrow). Therefore, refrigerant received from the third inlet 13 or the fourth inlet 14 is prevented from flowing inversely toward the first inlet 11. In the configuration illustrated in FIG. 11, it is desirable that the first inlet 11 face in the direction opposite to the direction of gravity. That is, it is desirable that the direction of the Z-axis arrow illustrated in FIG. 11 be opposite to the direction of gravity.

While FIG. 10 illustrates a case where the third plate 21c has the first supplementary flow passage 18a and the second supplementary flow passage 18b and the second plate 21b has the third inlet 13 and the fourth inlet 14, one or both of the two inlets may be provided in another plate. For example, two additional plates (not illustrated) may be stacked on the lower surface (the surface facing in the opposite direction of the Z-axis arrow) of the first plate 21a. In such a case, one of the two additional plates has the first supplementary flow passage 18a and the second supplementary flow passage 18b, and the other additional plate has the third inlet 13 and the fourth inlet 14. Furthermore, the first plate 21a has through-holes at positions facing the ends of the first supplementary flow passage 18a and the second supplementary flow passage 18b.

Now, how the flow switching device 1b according to Embodiment 3 works will be described with reference to FIGS. 12 and 13. The following description relates to a case where the flow switching device 1b is provided in a refrigerant circuit (not illustrated). FIG. 12 illustrates how refrigerant flows through the flow switching device illustrated in FIG. 10 when the refrigerant is received at the fourth inlet and is discharged from the third inlet. FIG. 13 illustrates how refrigerant flows through the flow switching device illustrated in FIG. 10 when the refrigerant is received at the third inlet and is discharged from the fourth inlet.

As illustrated in FIGS. 12 and 13, a refrigerant pipe 51 is connected to the fourth inlet 14. Furthermore, a refrigerant pipe 52 is connected to the third inlet 13. The first inlet 11 and the second inlet 12 are connected to each other by a refrigerant pipe 53.

As illustrated in FIG. 12, when refrigerant flows from the refrigerant pipe 51 and is received at the fourth inlet 14, the refrigerant flows through the fourth anisotropic-flow-passage row 16d illustrated in FIG. 11, further flows through the refrigerant pipe 53 illustrated in FIG. 12, and reaches the first inlet 11. The refrigerant having reached the first inlet 11 flows through the first anisotropic-flow-passage row 16a and is discharged from the third inlet 13 into the refrigerant pipe 52. In FIG. 12, the direction of the refrigerant flow in the refrigerant pipe 53 is represented by a solid-line arrow.

As illustrated in FIG. 13, when refrigerant flows from the refrigerant pipe 52 and is received at the third inlet 13, the refrigerant flows through the second anisotropic-flow-passage row 16b illustrated in FIG. 11, further flows through the refrigerant pipe 53 illustrated in FIG. 13, and reaches the first inlet 11. The refrigerant having reached the first inlet 11 flows through the third anisotropic-flow-passage row 16c and is discharged from the fourth inlet 14 into the refrigerant pipe 51. In FIG. 13, the direction of the refrigerant flow in the refrigerant pipe 53 is represented by a solid-line arrow.

In the flow switching device 1b according to Embodiment 3, the direction of the refrigerant flow in the refrigerant pipe 53 is the same between the cases illustrated in FIGS. 12 and 13. In a refrigeration cycle apparatus (not illustrated) including the flow switching device 1b, for example, when the operation mode is switched from one of the cooling operation and the heating operation to the other, the direction of the refrigerant flow in the refrigerant circuit is inverted except the direction of the refrigerant flow in the refrigerant pipe 53.

A bridge circuit refers to a circuit including a section where the refrigerant is made to flow in a constant direction with the use of a combination of four check valves. As described above with reference to FIGS. 12 and 13, the first anisotropic-flow-passage row 16a, the second anisotropic-flow-passage row 16b, the third anisotropic-flow-passage row 16c, and the fourth anisotropic-flow-passage row 16d form a bridge circuit.

(Modification 1)

A modification of the flow switching device 1b according to Embodiment 3 will now be described. FIG. 14 is a plan view of a first plate according to Modification 1 included in the flow switching device according to Embodiment 3, illustrating an exemplary configuration thereof. The forward direction is represented by arrows. A virtual line VL passes through the first inlet 11 and the second inlet 12. With reference to the virtual line VL, the first anisotropic-flow-passage row 16a and the third anisotropic-flow-passage row 16c are in line symmetry. Furthermore, with reference to the virtual line VL, the second anisotropic-flow-passage row 16b and the fourth anisotropic-flow-passage row 16d are in line symmetry.

One end of the first anisotropic-flow-passage row 16a and one end of the third anisotropic-flow-passage row 16c are connected to the first inlet 11. One end of the second anisotropic-flow-passage row 16b and one end of the fourth anisotropic-flow-passage row 16d are connected to the second inlet 12. The other end of the first anisotropic-flow-passage row 16a and the other end of the second anisotropic-flow-passage row 16b are connected to the third inlet 13. The other end of the third anisotropic-flow-passage row 16c and the other end of the fourth anisotropic-flow-passage row 16d are connected to the fourth inlet 14.

Modification 1 does not require the third plate 21c, illustrated in FIG. 10, having the first connecting flow passage 17, the first supplementary flow passage 18a, the second supplementary flow passage 18b, and the second connecting flow passage 19. The first plate 21a illustrated in FIG. 14 has a better weight balance between the left part and the right part thereof with reference to the virtual line VL and is easier to process with a laser. If the first to fourth anisotropic-flow-passage rows 16a to 16d are to be formed by pressing, the first plate 21a is easier to manufacture. The pressing process will be discussed in Embodiment 4.

Unlike a known check-valve bridge circuit formed of four check valves, the flow switching device 1b according to Embodiment 3 includes no movable elements and therefore generates reduced noise that may be generated by movable elements of check valves. Furthermore, the flow switching device 1b according to Embodiment 3 exerts the functions of four check valves in one plate member and therefore has a compact size.

Embodiment 4

Embodiment 4 relates to a case where the flow passages of the flow switching device described in Embodiment 1 are formed by pressing. While Embodiment 4 is based on the flow switching device described in Embodiment 1, Embodiment 4 may also be applied to the flow switching devices described in Embodiments 2 and 3. In Embodiment 4, elements that are the same as those described in any of Embodiments 1 to 3 are denoted by corresponding ones of the reference signs, and detailed description of such elements is omitted.

A flow switching device according to Embodiment 4 is configured as follows. FIG. 15 is a see-through diagram for describing a configuration of a flow switching device according to Embodiment 4. FIG. 16 is an exploded perspective view of the flow switching device according to Embodiment 4, illustrating an exemplary configuration thereof. FIG. 17 is a plan view of a first flow-passage plate and a second flow-passage plate, illustrated in FIG. 16.

In the flow switching device, 1c, illustrated in FIG. 15, one plate has a first flow passage 15a, which is formed of some parts of the flow passage 3 illustrated in FIG. 2; and another plate has a second flow passage 15b, which is formed of the remaining parts of the flow passage 3. In FIG. 15, the pattern of the first flow passage 15a is hatched with oblique lines, whereas the pattern of the second flow passage 15b is unhatched.

As illustrated in FIG. 16, the flow switching device 1c includes an upper lid plate 22, a first flow-passage plate 23a, a second flow-passage plate 23b, and a lower lid plate 24. The flow switching device 1c is obtained by stacking the lower lid plate 24, the second flow-passage plate 23b, the first flow-passage plate 23a, and the upper lid plate 22 in that order. The first flow-passage plate 23a has the first flow passage 15a, which pierces through the first flow-passage plate 23a. The second flow-passage plate 23b has the second flow passage 15b, which pierces through the second flow-passage plate 23b. The first flow-passage plate 23a further has a first inlet 11a, which serves as an interconnector through which an upper end part of the second flow-passage plate 23b is connected to the first inlet 11. The first flow-passage plate 23a further has a second inlet 12a, which serves as an interconnector through which a lower end part of the second flow-passage plate 23b is connected to the second inlet 12.

Referring to FIG. 17, the first flow passage 15a and the second flow passage 15b are patterned as follows. The first flow passage 15a includes a plurality of main second linear parts 7b. The second flow passage 15b includes a plurality of main first linear parts 7a and a plurality of subsidiary flow passages 8. In the exemplary configuration illustrated in FIG. 17, the second flow passage 15b further includes a connecting part 10, through which one of the subsidiary flow passages 8 that is closest to the second inlet 12a is connected to the second inlet 12a. The first flow passage 15a provided in the first flow-passage plate 23a forms a pattern in which the plurality of main second linear parts 7b are arranged at regular intervals between the first inlet 11a and the second inlet 12a. The second flow passage 15b provided in the second flow-passage plate 23b forms a pattern in which the main first linear parts 7a and the subsidiary flow passages 8 are arrange alternately.

Now, how the flow switching device 1c according to Embodiment 4 works will be described with reference to FIG. 17. First, a case where refrigerant received at the second inlet 12a flows into the second flow passage 15b will be discussed. This refrigerant flow is an inverse flow.

When refrigerant starts to flow from a position of the second flow passage 15b that faces the second inlet 12a toward the first inlet 11a (in the direction of the Y-axis arrow), some of refrigerant flows from the connecting part 10 into the first one of the subsidiary flow passages 8, whereas the remaining portion of the refrigerant flows from the connecting part 10 into the first one of the main second linear parts 7b provided in the first flow-passage plate 23a. The refrigerant portion flowing from the connecting part 10 provided in the second flow-passage plate 23b into the main second linear part 7b provided in the first flow-passage plate 23a needs to move in a stacking direction of the plate members. In contrast, the connecting part 10 and the subsidiary flow passage 8 connected thereto are provided in the same second flow-passage plate 23b. Therefore, refrigerant flows more easily from the connecting part 10 into the subsidiary flow passage 8 than from the connecting part 10 into the main second linear part 7b. Consequently, a greater amount of refrigerant flows from the connecting part 10 into the subsidiary flow passage 8 than from the connecting part 10 into the main second linear part 7b. The refrigerant portion having flowed through the subsidiary flow passage 8 and flowing into the main first linear part 7a next thereto merges with the refrigerant portion having flowed through the main second linear part 7b. At this point, the refrigerant portion of the greater amount hinders the other refrigerant portion, which is flowing out of the main second linear part 7b. Therefore, although the second flow passage 15b is one continuous flow passage as illustrated in FIG. 17, the refrigerant thereinside is prevented from flowing in the inverse direction.

Next, a case where refrigerant received at the first inlet 11a flows into the second flow passage 15b will be discussed. This refrigerant flow is a forward flow. When refrigerant starts to flow from a position of the second flow passage 15b that faces the first inlet 11a toward the second inlet 12a (in the opposite direction of the Y-axis arrow), some of the refrigerant flows from the first one of the main first linear parts 7a into the first one of the subsidiary flow passages 8, whereas the remaining portion of the refrigerant flows from the first one of the main first linear parts 7a into the first one of the main second linear parts 7b provided in the first flow-passage plate 23a. The refrigerant portion having flowed through the subsidiary flow passage 8 and flowing into the next one of the main first linear parts 7a merges with the refrigerant portion having flowed through the main second linear part 7b. At this point, the refrigerant portion flowing out of the subsidiary flow passage 8 flows along the refrigerant portion flowing out of the main second linear part 7b. Therefore, although the plurality of main second linear parts 7b are arranged at regular intervals as illustrated in FIG. 17 and a step is produced between each of the main first linear parts 7a and a corresponding one of the main second linear parts 7b in the stacking direction of the plate members, the refrigerant smoothly flows in the forward direction.

As for the flow switching device 1c, the first flow passage 15a and the second flow passage 15b can be formed by pressing performed on the respective plate members. Therefore, mass production of the flow switching device 1c is possible with a low manufacturing cost. Furthermore, since the second flow passage 15b is one continuous flow passage, the refrigerant flowing in the inverse direction does not move in the stacking direction of the plate members. In such a situation, refrigerant flows more easily into the subsidiary flow passages 8. Accordingly, the backward flow resistance is increased. Therefore, the effect of the check valve is enhanced. Thus, even in a case where the main flow passages 7 and the subsidiary flow passages 8 are provided over two separate plates, an increased backward flow resistance is generated while the forward flow resistance is kept small.

When viewed in the stacking direction in which the first flow-passage plate 23a and the second flow-passage plate 23b are stacked, a part of the pattern of the main first linear parts 7a may overlap the pattern of the main second linear parts 7b. The forward flow resistance and the backward flow resistance are adjustable by adjusting the area, S, of overlap between the pattern of the main first linear parts 7a and the pattern of the main second linear parts 7b.

While Embodiments 1 to 3 described above relate to a configuration in which the anisotropic flow passages 5 are provide in one plate, the anisotropic flow passages 5 of the flow switching device 1c according to Embodiment 4 are each formed by a combination of a plurality of plates. In Embodiment 4, a part of each anisotropic flow passage 5 is at a plate, on which neither the first inlet 11 nor the second inlet 12 is formed, of the plurality of plates. One part of the anisotropic flow passage 5 is provided in one plate, whereas the other part of the anisotropic flow passage 5 is provided in another plate. The plate having the other part of the anisotropic flow passage 5 may be the plate having one or both of the first inlet 11 and the second inlet 12. According to Embodiment 4, the anisotropic flow passage 5 serving as a check valve is divided into separate parts provided in respective plates, whereby the backward flow resistance is adjusted such that the check-valve function is ensured. Thus, while the check-valve function is ensured, automatic switching of the directions of the refrigerant flow is enabled. Furthermore, since the flow switching device 1c according to Embodiment 4 includes no movable elements such as valve bodies, the occurrence of noise that may be generated by any sliding motions is prevented, as with Embodiment 1.

(Modification 2)

A modification of the flow switching device according to Embodiment 4 will now be described. FIG. 18 is a see-through diagram for describing a configuration of a flow switching device according to Modification 2 of Embodiment 3. FIG. 19 is an exploded perspective view of the flow switching device according to Modification 2, illustrating an exemplary configuration thereof. FIG. 20 is a plan view of a first flow-passage plate and a second flow-passage plate, illustrated in FIG. 19.

In the flow switching device, 1d, illustrated in FIG. 18, one plate has a first flow passage 15a, which is formed of some parts of the flow passage 3 illustrated in FIG. 2; and another plate has a second flow passage 15b, which is formed of the remaining parts of the flow passage 3. In FIG. 18, the pattern of the first flow passage 15a is hatched with oblique lines, whereas the pattern of the second flow passage 15b is unhatched. The flow switching device 1d according to Modification 2 is different from the flow switching device 1c, described with reference to FIGS. 15 to 17, in the patterns of the first flow passage 15a and the second flow passage 15b.

As illustrated in FIG. 19, the flow switching device 1d includes an upper lid plate 22, a first flow-passage plate 23a, a second flow-passage plate 23b, and a lower lid plate 24. The flow switching device 1d is obtained by stacking the lower lid plate 24, the second flow-passage plate 23b, the first flow-passage plate 23a, and the upper lid plate 22 in that order. The first flow-passage plate 23a has the first flow passage 15a, which pierces through the first flow-passage plate 23a. The second flow-passage plate 23b has the second flow passage 15b, which pierces through the second flow-passage plate 23b.

Referring to FIG. 20, the first flow passage 15a and the second flow passage 15b are patterned as follows. The first flow passage 15a is a combination of a plurality of main flow passages 7 with a part thereof removed. The second flow passage 15b is a combination of a plurality of subsidiary flow passages 8 and the part of the plurality of main flow passages 7. In the exemplary configuration illustrated in FIG. 20, the first flow passage 15a forms a pattern in which one main second linear part 7b is connected in series with five main flow passages 7. The part of the plurality of main flow passages 7 in the exemplary configuration illustrated in FIG. 20 is a main first linear part 7a, which connects the first inlet 11a to the main second linear part 7b. The part of the plurality of main flow passages 7 is not limited to the main first linear part 7a that connects the first inlet 11a to the main second linear part 7b. The connecting part 10 is included in the second flow passage 15b, not in the first flow passage 15a. In the first flow-passage plate 23a, the first inlet 11a and the second inlet 12a are not connected to each other by one flow passage, and a part of the first flow passage 15a is provided in the second flow passage 15b. In such a configuration, not only the forward flow resistance is reduced, but also the check-valve function exerted by the backward flow resistance is maintained.

As illustrated in FIG. 20, the second flow passage 15b forms a pattern in which the plurality of subsidiary flow passages 8 are arranged at regular intervals between the first inlet 11a and the second inlet 12a. In the second flow-passage plate 23b, one of the subsidiary flow passages 8 that is closest to the first inlet 11a is connected to the first inlet 11a through the main first linear part 7a. Furthermore, in the second flow-passage plate 23b, one of the subsidiary flow passages 8 that is closest to the second inlet 12a is connected to the second inlet 12a through the connecting part 10.

Now, how the flow switching device 1d according to Modification 2 works will be described with reference to FIG. 20. First, a case where refrigerant received at the second inlet 12a flows into the second flow passage 15b will be discussed. This refrigerant flow is an inverse flow.

When refrigerant starts to flow from a position of the second flow passage 15b that faces the second inlet 12a toward the first inlet 11a (in the direction of the Y-axis arrow), some of the refrigerant flows from the connecting part 10 into the first one of the subsidiary flow passages 8, whereas the remaining portion of the refrigerant flows from the connecting part 10 into the first one of the main flow passages 7 provided in the first flow-passage plate 23a. The refrigerant portion flowing from the connecting part 10 provided in the second flow-passage plate 23b into the main flow passage 7 provided in the first flow-passage plate 23a needs to move in the stacking direction of the plate members. In contrast, the connecting part 10 and the subsidiary flow passage 8 connected thereto are provided in the same second flow-passage plate 23b. Therefore, refrigerant flows more easily from the connecting part 10 into the subsidiary flow passage 8 than from the connecting part 10 into the main flow passage 7. Consequently, a greater amount of refrigerant flows from the connecting part 10 into the subsidiary flow passage 8 than from the connecting part 10 into the main flow passage 7. The refrigerant portion having flowed through the subsidiary flow passage 8 and flowing into the main flow passage 7 merges with the refrigerant portion having flowed through the main flow passage 7. At this point, the refrigerant portion of the greater amount hinders the other refrigerant portion, which is flowing in the main flow passage 7. Therefore, although the first flow passage 15a is one continuous flow passage as illustrated in FIG. 20, the refrigerant thereinside is prevented from flowing in the inverse direction.

Next, a case where refrigerant received at the first inlet 11a flows into the second flow passage 15b will be discussed. This refrigerant flow is a forward flow. When refrigerant starts to flow from a position of the second flow passage 15b that faces the first inlet 11a toward the second inlet 12a (in the opposite direction of the Y-axis arrow), some of the refrigerant flows from the main first linear part 7a into the first one of the subsidiary flow passages 8, whereas the remaining portion of the refrigerant flows from the main first linear part 7a into the main second linear part 7b provided in the first flow-passage plate 23a. The refrigerant portion having flowed into the main second linear part 7b provided in the first flow-passage plate 23a further flows through the five main flow passages 7 connected in series in the same first flow-passage plate 23a. Therefore, as illustrated in FIG. 17, the refrigerant portion is allowed to flow through the first flow passage 15a with no hinderance. Hence, although a part of the plurality of main flow passages 7 is provided in the second flow-passage plate 23b, the refrigerant smoothly flows in the forward direction.

As for the flow switching device 1d according to Modification 2 as well, the first flow passage 15a and the second flow passage 15b can be formed by pressing performed on the respective plate members. Therefore, mass production of the flow switching device 1d is possible with a low manufacturing cost. Furthermore, the refrigerant flowing in the inverse direction does not move in the stacking direction of the plate members. Therefore, the effect of the check valve is enhanced, as with the flow switching device 1c. Furthermore, the forward flow resistance in the flow switching device 1d according to Modification 2 is smaller than in the flow switching device 1c.

According to Embodiment 4, the main flow passages 7 and the subsidiary flow passages 8 are provided over a plurality of separate plate members. Therefore, the flow passages can be obtained by press forming. Consequently, the productivity of the flow switching device is increased with a low manufacturing cost.

According to Embodiment 4, the flow passage 3 is divided into separate flow-passage parts provided in two respective flow-passage plates. Such a configuration provides a higher degree of design freedom in one or both of the length and the width of the flow-passage parts provided in the flow-passage plates. For example, the flow-passage part provided in one of the two flow-passage plates may have a greater width than the flow-passage part provided in the other flow-passage plate. The balance of flow rate between the forward flow and the inverse flow is adjustable by adjusting the designed lengths and widths of the flow-passage parts provided in the respective flow-passage plates. Furthermore, flow switching devices of various kinds of specifications are manufacturable by providing various options, including specifications for an enhanced check-valve effect and specifications for a reduced check-valve effect. If the flow switching device according to Embodiment 4 is included in a refrigeration cycle apparatus, one of the two flow-passage plates may have a flow-passage part that is common to all types of the refrigeration cycle apparatus, whereas the other flow-passage plate may have a flow-passage part whose width is adjusted in correspondence with the type of the refrigeration cycle apparatus. In such a case, one of the flow-passage plate that is common to all types of the refrigeration cycle apparatus may be put to mass production, whereas the other flow-passage plate may be manufactured for each type of the refrigeration cycle apparatus. Thus, flow switching devices that meet different needs for the refrigeration cycle apparatus can be manufactured in a shorter time.

Embodiment 5

Embodiment 5 relates to a refrigeration cycle apparatus including the flow switching device described in Embodiment 3. While Embodiment 5 takes the case of the flow switching device 1b illustrated in FIG. 10, the first plate 21a may be the one illustrated in FIG. 14. In Embodiment 5, elements that are the same as those described in any of Embodiments 1 to 4 are denoted by corresponding ones of the reference signs, and detailed description of such elements is omitted.

The refrigeration cycle apparatus according to Embodiment 5 is configured as follows. FIG. 21 is a refrigerant circuit diagram illustrating an exemplary configuration of a refrigeration cycle apparatus according to Embodiment 5. The refrigeration cycle apparatus, 100, includes a heat-source-side unit 60 and a load-side unit 70. The heat-source-side unit 60 and the load-side unit 70 are connected to each other by a gas extension pipe 73 and a liquid extension pipe 74. The heat-source-side unit 60 includes a compressor 31, a four-way valve 36, the flow switching device 1b, a heat-source-side heat exchanger 61, and an expansion valve 33. The load-side unit 70 includes a load-side heat exchanger 71. The compressor 31, the heat-source-side heat exchanger 61, the expansion valve 33, and the load-side heat exchanger 71 are connected to one another by refrigerant pipes to form a refrigerant circuit 55, through which refrigerant is made to circulate. The compressor 31, the four-way valve 36, and the expansion valve 33 are connected to a controller (not illustrated) configured to control the refrigeration cycle circuit of the refrigeration cycle apparatus 100.

The heat-source-side heat exchanger 61 includes a main heat exchanger 61a and a supplementary heat exchanger 61b. The four-way valve 36 is connected to the refrigerant suction port and the refrigerant discharge port of the compressor 31, to the gas extension pipe 73, and to a refrigerant pipe 51. In the flow switching device 1b, the fourth inlet 14 is connected to the refrigerant pipe 51, the first inlet 11 and the second inlet 12 are connected to each other by a refrigerant pipe 53, and the third inlet 13 is connected to the expansion valve 33 by a refrigerant pipe 52. The refrigerant pipe 53 is provided with the main heat exchanger 61a. The refrigerant pipe 52 is provided with the supplementary heat exchanger 61b. The refrigerant circuit 55 including the heat-source-side heat exchanger 61 divided into the main heat exchanger 61a and the supplementary heat exchanger 61b includes the flow switching device 1b, which serves as a refrigerant device.

Now, how the refrigeration cycle apparatus 100 according to Embodiment 5 operates will be described with reference to FIGS. 21 to 24. First, a cooling operation of the refrigeration cycle apparatus 100 is as follows. In FIG. 21, the refrigerant flow is represented by broken-line arrows, and the air flow is represented by a white arrow. The heat-source-side heat exchanger 61 serves as a condenser. FIG. 22 illustrates the direction of a refrigerant flow generated in the flow switching device when the refrigeration cycle apparatus illustrated in FIG. 21 is in the cooling operation.

When the refrigeration cycle apparatus 100 starts the cooling operation, the four-way valve 36 sets the refrigerant flow such that the refrigerant discharged from the compressor 31 flows into the heat-source-side heat exchanger 61. The refrigerant discharged from the compressor 31 flows through the refrigerant pipe 51 into the fourth inlet 14 of the flow switching device 1b. The refrigerant received at the fourth inlet 14 flows through the fourth anisotropic-flow-passage row 16d in the forward direction and is discharged from the second inlet 12 into the refrigerant pipe 53. While the refrigerant is flowing through the refrigerant pipe 53, the refrigerant passes through the main heat exchanger 61a. In the main heat exchanger 61a, the refrigerant exchanges heat with outdoor air and then flows into the first inlet 11 of the flow switching device 1b.

In the flow switching device 1b illustrated in FIG. 22, since the pressure of the refrigerant is higher at the fourth inlet 14 than at the first inlet 11, the refrigerant does not flow into the third anisotropic-flow-passage row 16c but flows into the first anisotropic-flow-passage row 16a in the forward direction and is discharged from the third inlet 13 into the refrigerant pipe 52. While the refrigerant is flowing through the refrigerant pipe 52, the refrigerant passes through the supplementary heat exchanger 61b. In the supplementary heat exchanger 61b, the refrigerant exchanges heat with outdoor air and then flows into the expansion valve 33. In the expansion valve 33, the refrigerant is expanded and then flows through the liquid extension pipe 74 into the load-side unit 70. The refrigerant having flowed into the load-side unit 70 exchanges heat in the load-side heat exchanger 71 with air in the air-conditioning target space, whereby the air in the air-conditioning target space is cooled. The refrigerant having undergone heat exchange flows through the gas extension pipe 73 and returns into the heat-source-side unit 60. The refrigerant returned into the heat-source-side unit 60 further flows through the four-way valve 36 toward the compressor 31 to be sucked into the compressor 31.

Next, a heating operation of the refrigeration cycle apparatus 100 is as follows. FIG. 23 illustrates the direction of a refrigerant flow generated when the refrigeration cycle apparatus illustrated in FIG. 21 is in the heating operation. In FIG. 21, the refrigerant flow is represented by broken-line arrows, and the air flow is represented by a white arrow. The heat-source-side heat exchanger 61 serves as an evaporator. FIG. 24 illustrates the direction of the refrigerant flow generated in the flow switching device when the refrigeration cycle apparatus illustrated in FIG. 21 is in the heating operation.

When the refrigeration cycle apparatus 100 starts the heating operation, the four-way valve 36 sets the refrigerant flow such that the refrigerant discharged from the compressor 31 flows into the load-side heat exchanger 71. The refrigerant discharged from the compressor 31 flows through the four-way valve 36 and the gas extension pipe 73 into the load-side unit 70. The refrigerant having flowed into the load-side unit 70 exchanges heat in the load-side heat exchanger 71 with air in the air-conditioning target space, whereby the air in the air-conditioning target space is heated. The refrigerant having undergone heat exchange flows through the liquid extension pipe 74 and returns into the heat-source-side unit 60. The refrigerant returned into the heat-source-side unit 60 is expanded by the expansion valve 33.

The refrigerant expanded by the expansion valve 33 flows through the refrigerant pipe 52 into the supplementary heat exchanger 61b. In the supplementary heat exchanger 61b, the refrigerant exchanges heat with outdoor air and then flows into the third inlet 13 of the flow switching device 1b. The refrigerant received at the third inlet 13 flows through the second anisotropic-flow-passage row 16b in the forward direction and is discharged from the second inlet 12 into the refrigerant pipe 53. While the refrigerant is flowing through the refrigerant pipe 53, the refrigerant passes through the main heat exchanger 61a. In the main heat exchanger 61a, the refrigerant exchanges heat with outdoor air and then flows into the first inlet 11 of the flow switching device 1b.

In the flow switching device 1b illustrated in FIG. 24, since the pressure of the refrigerant is higher at the third inlet 13 than at the first inlet 11, the refrigerant does not flow into the first anisotropic-flow-passage row 16a but flows into the third anisotropic-flow-passage row 16c in the forward direction and is discharged from the fourth inlet 14 into the refrigerant pipe 51. The refrigerant having flowed through the refrigerant pipe 51 further flows through the four-way valve 36 toward the compressor 31 to be sucked into the compressor 31.

Thus, in the refrigeration cycle apparatus 100, although the direction of the refrigerant flow in the refrigerant circuit 55 is invertible by the four-way valve 36, the direction of the refrigerant flow in the main heat exchanger 61a is constant relative to the air flow. In Embodiment 5, the main heat exchanger 61a is configured to generate counterflow of refrigerant, which is not illustrated.

Here, an exemplary heat-source-side heat exchanger having a counterflow configuration will be described. FIG. 25 is a perspective view of a heat-source-side heat exchanger having an exemplary counterflow configuration. The heat-source-side heat exchanger, 80, includes a first heat exchanger 80a and a second heat exchanger 80b; a first header 81, which is provided at the refrigerant entrance/exit of the first heat exchanger 80a; a second header 82, which is provided at the refrigerant entrance/exit of the second heat exchanger 80b; and an interconnector 83. The interconnector 83 is configured to allow the refrigerant to flow between the first heat exchanger 80a and the second heat exchanger 80b. The air flow is represented by an arrow 85, hatched with oblique lines.

When the heat-source-side heat exchanger 80 illustrated in FIG. 25 serves as an evaporator, the refrigerant received at the first header 81 flows into the first heat exchanger 80a, which is located leeward, and flows through the interconnector 83 into the second heat exchanger 80b, which is located windward. Then, the refrigerant is discharged from the heat-source-side heat exchanger 80 through the second header 82. Thus, the direction of the refrigerant flow in the first heat exchanger 80a relative to the air flow is opposite to the direction of the refrigerant flow in the second heat exchanger 80b relative to the air flow.

FIG. 26 illustrates exemplary air-temperature distributions in the heat-source-side heat exchanger illustrated in FIG. 25 that is operating as an evaporator. FIG. 26 includes conceptual diagrams of refrigerant- and air-temperature distributions for parallel flow and counterflow. In FIG. 26, refrigerant temperature is represented by broken lines, and air temperature is represented by solid lines.

In a case where the air flow to the evaporator is the counterflow, as illustrated in FIG. 26, a more distinct temperature difference between refrigerant and air is produced at the refrigerant exit of the heat-source-side heat exchanger 80 than in a case where the air flow to the evaporator is the parallel-flow. For example, if the refrigerant is a refrigerant mixture whose temperature is gradient, the temperature of the refrigerant also rises while the refrigerant is under evaporation and is therefore in the state of two-phase gas-liquid. In the case of a refrigerant mixture as well, a more distinct temperature difference between refrigerant and air is produced at the refrigerant exit of the heat-source-side heat exchanger 80 than in an evaporator having a parallel-flow configuration. Therefore, improved heat-transfer performance is provided.

The direction of the refrigerant flow described with reference to FIG. 25 also applies to a case where the main heat exchanger 61a illustrated in FIG. 21 is the heat-source-side heat exchanger 80 illustrated in FIG. 25, and to a case where the heat-source-side heat exchanger 80 illustrated in FIG. 25 serves as a condenser. That is, the main heat exchanger 61a generates counterflow both when serving as a condenser and when serving as an evaporator. Accordingly, the main heat exchanger 61a exerts improved heat-transfer performance in both operation modes of the heating operation and the cooling operation.

While Embodiment 5 relates to a case where the flow switching device 1b is applied to the heat-source-side heat exchanger 61, the flow switching device 1b may alternatively be applied to the load-side heat exchanger 71. Furthermore, the heat-source-side heat exchanger 61 does not necessarily need to include the supplementary heat exchanger 61b.

Advantageous effects of Embodiment 5 are as follows. A known check-valve bridge circuit requires spaces for providing movable elements that enable valve bodies to move. In a heat exchanger including a main heat exchanger and a supplementary heat exchanger, providing such a known check-valve bridge circuit between the main heat exchanger and the supplementary heat exchanger reduces the size of the heat exchanger. In contrast, the flow switching device 1b according to Embodiment 5 employs a configuration in which flow passages are provided in a stack of a plurality of plate members. Such a configuration occupies a smaller space for installation than the known check-valve bridge circuit. Consequently, the size of the heat exchanger can be increased.

FLOW SWITCHING DEVICE AND REFRIGERATION CYCLE APPARATUS INCLUDING THE SAME

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