DISTRIBUTOR, HEAT EXCHANGER, AND HEAT PUMP APPARATUS

TECHNICAL FIELD

The present disclosure relates to a distributor that distributes refrigerant to a plurality of heat transfer tubes, a heat exchanger including this distributor, and a heat pump apparatus including this distributor.

BACKGROUND ART

A distributor has a double-pipe configuration of an outer pipe and an inner pipe (see, for example, Patent Literature 1). In such a distributor, the inner pipe is provided with a refrigerant outlet also called an orifice. Refrigerant flowing into a flow passage inside the inner pipe in the distributor is ejected into a space between the inner pipe and the outer pipe via a plurality of the refrigerant outlets and flows from this space into a plurality of heat transfer tubes.

CITATION LIST
Patent Literature

- Patent Literature 1: Japanese Patent No. 6523858

SUMMARY OF INVENTION
Technical Problem

In Patent Literature 1, the refrigerant is ejected through the orifices provided in the inner pipe, so that the refrigerant is uniformly distributed. However, in a configuration as in the distributor of Patent Literature 1 in which only one inner pipe is provided inside an outer pipe, the whole of the refrigerant that is distributed to the plurality of heat transfer tubes passes through one inner pipe, with the result that a pressure loss of the refrigerant in the distributor undesirably increases.

The present disclosure has been made to solve the above problem and has an object to provide a distributor, a heat exchanger, and a heat pump apparatus each configured to eliminate or reduce an increase in pressure loss while maintaining uniform distribution through orifices.

Solution to Problem

A distributor according to an embodiment of the present disclosure includes an outer wall portion having a cylindrical shape and extending in a transverse direction and a plurality of cylindrical portions extending in the transverse direction, the plurality of cylindrical portions being provided in the outer wall portion or in a hollow portion inside the outer wall portion and each having a flow passage having a circular cross-section inside the cylindrical portion. The plurality of cylindrical portions are provided parallel to each other. The outer wall portion has a plurality of connecting ports formed in an upper or lower part of the outer wall portion and spaced apart from each other in the transverse direction. Each of the plurality of cylindrical portions has a plurality of orifices provided in the cylindrical portion and spaced apart from each other in the transverse direction.

Further, a heat exchanger according to an embodiment of the present disclosure includes a plurality of heat transfer tubes, arrayed in the transverse direction, that extend in an up-down direction and two headers provided at both respective ends of the plurality of heat transfer tubes and that each distribute and merge refrigerant, At least one of the two headers includes the above distributor. Some of the plurality of heat transfer tubes are connected to the plurality of connecting ports of the distributor.

Further, a heat pump apparatus according to an embodiment of the present disclosure includes a refrigerant circuit including the above heat exchanger and a compressor configured to compress the refrigerant.

Advantageous Effects of Invention

Each of the distributor, the heat exchanger, and the heat pump apparatus according to an embodiment of the present disclosure includes the plurality of cylindrical portions each having a flow passage having a circular cross-section inside the cylindrical portion, and the plurality of cylindrical portions are provided parallel to each other in the outer wall portion or the hollow portion. This causes refrigerant to diverge into a plurality of the flow passages. This makes it possible to make the flow passage area per cylindrical portion smaller than that in a case of some configuration in which refrigerant is distributed to the plurality of heat transfer tubes via only one inner pipe.

This results in making it possible to provide a distributor, a heat exchanger, and a heat pump apparatus each configured to eliminate or reduce an increase in pressure loss while maintaining uniform distribution through orifices.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing an example of a heat exchanger including a distributor according to Embodiment 1.

FIG. 2 is a cross-sectional view showing an A-A cross-section of the distributor shown in FIG. 1.

FIG. 3 is a cross-sectional view showing an example of an end divider shown in FIG. 1.

FIG. 4 is a refrigerant circuit diagram of a heat pump apparatus including the heat exchanger shown in FIG. 1.

FIG. 5 is a schematic view showing the position of an orifice in a cylindrical portion of a distributor according to Embodiment 2.

FIG. 6 is a graph showing an effect on the liquid-level angle of refrigerant shown in FIG. 5 by the quality of the refrigerant.

FIG. 7 is a schematic view showing a first modification of cylindrical portions of the distributor according to Embodiment 2.

FIG. 8 is a cross-sectional view showing an example of a distributor according to Embodiment 3.

FIG. 9 is a schematic view showing a second modification of the distributor according to Embodiment 3.

FIG. 10 is a cross-sectional view showing an example of a distributor according to Embodiment 4.

FIG. 11 is a cross-sectional view showing an example of a distributor according to Embodiment 5.

FIG. 12 is a cross-sectional view showing a B-B cross-section of the distributor shown in FIG. 11.

FIG. 13 is a cross-sectional view showing a C-C cross-section of the distributor shown in FIG. 11.

FIG. 14 is a cross-sectional view showing an example of a distributor according to Embodiment 6.

DESCRIPTION OF EMBODIMENTS
Embodiment 1

FIG. 1 is a cross-sectional view showing an example of a heat exchanger 100 including a distributor 20 according to Embodiment 1. FIG. 2 is a cross-sectional view showing an A-A cross-section of the distributor 20 shown in FIG. 1. FIG. 3 is a cross-sectional view showing an example of an end divider 23 shown in FIG. 1. A configuration of the heat exchanger 100 is described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the heat exchanger 100 includes a plurality of heat transfer tubes 1, first and second headers 2a and 2b disposed at both respective ends of the plurality of heat transfer tubes 1, and two pipes 3a and 3b, which serve as an inlet and an outlet through which refrigerant flows into and out of the heat exchanger 100. Further, although not illustrated, the heat exchanger 100 includes a plurality of fins. In the following description, the first header 2a and the second header 2b are sometimes referred to simply as “headers” in a case in which they are not particularly distinguished from each other Each of the headers has a header outer wall having a cylindrical shape. In FIG. 1, the arrow outlines and the solid arrows shown in the headers indicate directions in which refrigerant flows,

Three directions orthogonal to one another are here defined as a first direction D1, a second direction D2, and a third direction D3 (see FIG. 2), and the first direction D1 is defined as a longitudinal direction parallel with long sides of the headers, i.e., an axial direction. In the heat exchanger 100, the plurality of heat transfer tubes 1 are arrayed and regularly spaced apart from each other in the first direction D1, and each of the plurality of heat transfer tubes 1 extends in the second direction D2.

The following description uses directive terms (such as “top”, “bottom”, “right”, “left”, “front”, and “back”) as appropriate for ease of comprehension; however, this is for illustrative purposes, and these terms are not intended to limit the present disclosure. Unless otherwise clearly described, these directive terms mean directions as seen from the front of the heat exchanger 100 as shown in FIG. 1. Further, in the following description, for ease of comprehension, the first direction D1, which is a longitudinal direction of the headers, is defined as a transverse direction across the heat exchanger 100, and the second direction D2, which is a longitudinal direction parallel with long sides of the plurality of heat transfer tubes 1, is defined as an up-down direction from the top of the heat exchanger 100 to the bottom.

The heat transfer tubes 1 are, for example, flat tubes. The plurality of heat transfer tubes 1 have upper ends 1e inserted in the header outer wall of the first header 2a, and the plurality of heat transfer tubes 1 have lower ends 1e inserted in the header outer wall of the second header 2b.

In a lower portion of the header outer wall of the first header 2a, a plurality of connecting ports 21o into which the upper ends 1e of the heat transfer tubes 1 are inserted are formed and spaced apart from each other in the transverse direction. Further, in an upper portion of the header outer wall of the second header 2b, a plurality of connecting ports 210 into which the lower ends 1e of the heat transfer tubes 1 are inserted are formed and spaced apart from each other in the transverse direction. A space through which refrigerant flows is defined inside each of the first and second headers 2a and 2b. The space inside the first header 2a and the space inside the second header 2b communicate with each other via the plurality of heat transfer tubes 1, The first header 2a and the second header 2b each distribute refrigerant to the plurality of heat transfer tubes 1 and each cause flows of refrigerant from the plurality of heat transfer tubes 1 to merge with each other. Further, in the example shown in FIG. 1, a pipe 3a is provided at a left end of the second header 2b, and a pipe 3b is provided at a right end of the second header 2b.

Each of the plurality of fins (not illustrated) is, for example, a corrugated fin formed in the shape of waves. Each fin is disposed between adjacent heat transfer tubes 1 and joined to surfaces of both the heat transfer tubes 1. The fins are intended to transfer heat to the heat transfer tubes 1 to improve efficiency of heat exchange between air and refrigerant.

For example, the plurality of heat transfer tubes 1, the plurality of fins (not illustrated), the first header 2a, and the second header 2b may all be made of aluminum. In this case, they are joined to one another, for example, by brazing.

At least one of the first and second headers 2a and 2b includes a distributor 20. Further, in a case in which a distributor 20 is provided in part of one of the first and second headers 2a and 2b in the longitudinal direction, the header not provided with no distributor 20 is provided with a divider 4 that divides the space inside the header into a plurality of spaces. In the example shown in FIG. 1, the right half of the first header 2a in the longitudinal direction (first direction D1) serves as a distributor 20, and the second header 2b, which includes no distributor 20, has a divider 4 that divides the space inside the second header 2b into a left space and a right space.

A configuration of the distributor 20 is described with reference to FIGS. 1 to 3. The distributor 20 includes an outer wall portion 21 and cylindrical portions 22. The outer wall portion 21 has a cylindrical shape and has a hollow portion 21a. The cylindrical portions 22 are provided in the hollow portion 21a, extend in the transverse direction (first direction D1), and each have, in its inside, a flow passage 22p. The outer wall portion 21 of the distributor 20 is the right half of the header outer wall of the first header 2a. The cylindrical portion 22 has a plurality of orifices 22o provided and regularly spaced apart from each other in a flow passage axial direction, i.e. the first direction D1. In the example shown in FIG. 1, eighteen heat transfer tubes 1 are connected to the outer wall portion 21 of the distributor 20, and the cylindrical portion 22 has seven orifices 22o provided in the transverse direction. The cylindrical portion 22, which extends in the transverse direction in FIG. 1, comprises a plurality of the cylindrical portions 22 as shown in FIG. 2, and the plurality of cylindrical portions 22 are provided parallel to each other in the hollow portion 21a. The orifices 22o have, for example, circular shapes. Alternatively, the shapes of the orifices 22o may be slit-like shapes.

As shown in FIG. 2, in a cross-section perpendicular to an axial direction parallel with the axis of the cylindrical portion 22, the flow passage 22p has a circular cross-section. In the example shown in FIG. 2, the cylindrical portion 22 has a circular cylindrical shape. In the following description, part of the cylindrical portion 22 that is higher than a line passing through the center C1 of the cylindrical portion 22 and parallel to the third direction D3 (i.e. a front-back direction from the front of the heat exchanger 100 to the back) is sometimes referred to as “upper cylindrical portion”, and part of the cylindrical portion 22 that is lower than the line is sometimes referred to as “lower cylindrical portion”.

In the cross-section perpendicular to the axial direction of the cylindrical portion 22, the orifices 22o may be provided in any positions. For example, providing the orifices 22o in one of the upper and lower cylindrical portions, which are upper and lower halves, and that is closer, than is the other, to the connecting ports 210 of the outer wall portion 21 in which the heat transfer tubes 1 are inserted shortens the distance between the ends 1e of the heat transfer tubes 1 and the orifices 22o. In the example shown in FIG. 2, the connecting ports 21o are formed in a lower part of the outer wall portion 21 of the distributor 20, the orifices 22o are provided in the lower cylindrical portion of each cylindrical portion 22,

Further, the distributor 20 includes an end divider 23 provided at one end of the outer wall portion 21 in the first direction D1 such that the end divider 23 closes a space located further inward than the outer wall portion 21 and further outward than a plurality of the flow passages 22p. In the example shown in FIG. 1, the end divider 23 is provided at a left end of the distributor 20 in the transverse direction (first direction D1). As shown in FIG. 3, the end divider 23 may be, for example, a plate-like part disposed such that the plate-like part extends along a plane perpendicular to the first direction D1 and provided with substantially circular openings 23a, which are connected to the flow passages 22p. The number of openings 23a provided in the end divider 23 is equal to the number of flow passages 22p.

As shown in FIG. 1, a right end face of each cylindrical portion 22 is connected to an inner surface of a right end of the first header 2a, and a right end of the hollow portion 21a of the distributor 20 is closed by the right end of the first header 2a. Further, a left end face of each cylindrical portion 22 is connected to an end of the corresponding opening 23a at a right side surface of the end divider 23, and a left end of the hollow portion 21a located further outward than the plurality of cylindrical portions 22 is closed by the end divider 23.

The openings 23a of the end divider 23 cause a left space inside the first header 2a to communicate with the plurality of flow passages 22p in the distributor 20. The aforementioned orifices 22o cause the flow passages 22p to communicate with a space in the hollow portion 21a located outside the cylindrical portions 22. The plurality of heat transfer tubes 1 connected to the outer wall portion 21 of the distributor 20 are connected to part of the second header 2b located further rightward than the divider 4 and cause the space in the hollow portion 21a of the distributor 20 located outside the cylindrical portions 22 to communicate with a right space inside the second header 2b. The divider 4 is formed such that the divider 4 prevents refrigerant flowing into the right space in the second header 2b via the plurality of heat transfer tubes 1 from the distributor 20 of the first header 2a from becoming mixed with refrigerant in the left space in the second header 2b, that is, refrigerant yet to flow into the first header 2a.

Next, operation of the heat exchanger 100 is described with reference to FIG. 1. Refrigerant flows from the pipe 3a into the left space in the second header 2b, is distributed to a plurality of heat transfer tubes 1 connected to this left space, exchanges heat with air while going up through these heat transfer tubes 1, and flows into the left space in the first header 2a. The refrigerant flowing into the left space in the first header 2a flows into the plurality of flow passages 22p of the distributor 20 via the openings 23a of the end divider 23. While flowing rightward through the flow passages 22p, the refrigerant flowing into the flow passages 22p via the openings 23a is ejected into the space in the hollow portion 21a located outside the cylindrical portions 22 via the plurality of orifices 22o provided and spaced apart from each other in the cylindrical portions 22 and flows into a plurality of heat transfer tubes 1 connected to the distributor 20. The refrigerant flowing into these heat transfer tubes 1 from the distributor 20 exchanges heat with air while going down through the heat transfer tubes 1, flows into the right space in the second header 2b, and then flows out of the heat exchanger 100 through the pipe 3b. In the heat exchanger 100, the flow of refrigerant is not limited to one direction, and refrigerant may flow in the opposite direction. That is, refrigerant flowing into the heat exchanger 100 via the pipe 3b may flow in a direction in which the refrigerant flows out via the pipe 3a after exchanging heat at the plurality of heat transfer tubes 1.

Although, in the example shown in FIG. 1, the distributor 20 is provided in the right half of the first header 2a in the first direction D1, the distributor 20 may be provided in any location or area in the first header 2a. For example, the distributor 20 may be provided in the whole area of the first header 2a in the first direction D1. Further, although, in the example shown in FIG. 1, the distributor 20 is provided only in the first header 2a, which is the upper one of the first and second headers 2a and 2b, a distributor 20 may be provided in the second header 2b, or distributors 20 may be provided in both the first header 2a and the second header 2b. Further, the location in one header where the divider 4 is provided may be determined according to the location and area in the other header where the distributor 20 is provided. Further, the locations in the heat exchanger 100 where the pipes 3a and 3b are provided are not limited to the locations shown in FIG. 1. Further, the number of orifices 22o in each cylindrical portion 22 and a spacing between orifices 22o are not limited to the above case.

FIG. 4 is a refrigerant circuit diagram of a heat pump apparatus 10 including the heat exchanger 100 shown in FIG. 1. In FIG. 4, the arrow outlines indicate directions in which refrigerant flows. The heat pump apparatus 10 includes a refrigerant circuit 10a configured to transfer heat through the use of latent heat of evaporation and condensation of the refrigerant. Examples of the heat pump apparatus 10 include an air-conditioning apparatus configured to heat the interior of a room with an evaporator installed outdoors and a condenser installed indoors and a hot-water supply system configured to make water warm or hot heated by a condenser.

The following describes a case in which as shown in FIG. 4, the above heat exchanger 100 is provided in the refrigerant circuit 1 Ca such that the heat exchanger 100 serves as an evaporator during heating operation of the heat pump apparatus 10. Alternatively, the heat exchanger 100 may be provided in the refrigerant circuit 10a such that the heat exchanger 100 serves as a condenser during heating operation of the heat pump apparatus 10.

The refrigerant circuit 10a is formed by a compressor 11, a heat exchanger 13, a pressure reducer 14, and the heat exchanger 100 being connected to one another by refrigerant pipes. The compressor 11 sucks in low-pressure gas refrigerant, compresses the low-pressure gas refrigerant into high-pressure gas refrigerant, discharges the high-pressure gas refrigerant, and causes the high-pressure gas refrigerant to circulate through the refrigerant circuit 10a. The heat exchanger 13 and the heat exchanger 100 cause the refrigerant and air to exchange heat with each other. The pressure reducer 14 is, for example, an expansion valve and expands and decompresses the refrigerant.

The compressor 11 may be an inverter compressor or other devices whose capacity, that is, delivery rate per unit time, is controlled by varying the operating frequency. Configuring the compressor 11 in this way makes it possible to adjust the frequency of the compressor 11 to vary the amount of refrigerant that circulates through the refrigerant circuit 10a and vary the amount of heat that moves through a refrigeration cycle according to a load or other conditions. Further, using as the pressure reducer 14, a valve whose opening degree is continuously variable makes it possible to vary the pressure of refrigerant that circulates through the refrigerant circuit 10a.

Further, in the example shown in FIG. 1, the refrigerant circuit 10a further includes a flow switching device 12. The flow switching device 12 is configured to switch the flow passages of refrigerant discharged from the compressor 11 and is, for example, a four-way valve. It should be noted that a configuration of the refrigerant circuit 10a is not limited to the above configuration. For example, the flow switching device 12 may be omitted.

The flow switching device 12 enables switching between cooling and heating. In a heating operation, the refrigerant discharged from the compressor 11 flows through the heat exchanger 13, the pressure reducer 14, and the heat exchanger 100 in sequence and returns to the compressor 11. Meanwhile, in a cooling operation, the refrigerant discharged from the compressor 11 flows through the heat exchanger 100, the pressure reducer 14, and the heat exchanger 13 in sequence and returns to the compressor 11. One of the heat exchangers 13 and 100 that serves as a condenser turns high-pressure gas refrigerant into liquid refrigerant by causing the high-pressure gas refrigerant to reject heat to outside air. One of the heat exchangers 13 and 100 that serves as an evaporator evaporates liquid refrigerant contained in low-pressure refrigerant into gas refrigerant by causing the liquid refrigerant to remove heat from outside air.

As noted above, a distributor 20 according to Embodiment 1 includes an outer wall portion 21 having a cylindrical shape, extending in a transverse direction (first direction D1), and having a hollow portion 21a and a plurality of cylindrical portions 22 extending in the transverse direction, being provided in the hollow portion 21a, and each having a flow passage 22p having a circular cross-section inside the cylindrical portion 22. The plurality of cylindrical portions 22 are provided parallel to each other. The outer wall portion 21 has a plurality of connecting ports 210 formed in an upper or lower part of the outer wall portion 21 and spaced apart from each other in the transverse direction. Each of the cylindrical portions 22 has a plurality of orifices 22o provided in the cylindrical portion 22 and spaced apart from each other in the transverse direction.

With this configuration, the distributor 20 includes a plurality of cylindrical portions 22 each having a flow passage 22p having a circular cross-section inside the cylindrical portion 22, and the plurality of cylindrical portions 22 are provided parallel to each other in the outer wall portion 21 or in the hollow portion 21a. This causes refrigerant to diverge into a plurality of the flow passages 22p. The refrigerant flowing into each of the flow passages 22p of the plurality of cylindrical portions 22 is distributed to the plurality of heat transfer tubes 1 via the plurality of orifices 22o. Therefore, the present disclosure makes it possible to make the area of a flow passage 22p per cylindrical portion 22 smaller than that in a case of some configuration in which refrigerant is distributed to the plurality of heat transfer tubes 1 via only one inner pipe. This makes it possible, while keeping an effect of improving refrigerant distribution by including the orifices 22o, to reduce a pressure loss of refrigerant or to both avoid an increase in pressure loss and reduce the size of the distributor 20. Further, achieving a reduction in size of the distributor 20 makes it possible to reduce material costs and reduce the amount of refrigerant of the heat exchanger 100.

Further, the plurality of cylindrical portions 22 are disposed in the hollow portion 21a of the distributor 20. This makes it unnecessary to change the shape of a header outer wall in mounting the distributor 20 in a header, thus making application easy.

Further, each of the plurality of cylindrical portions 22 has a circular cylindrical shape. This makes it possible to easily form a flow passage 22p having a circular cross-section.

Further, the distributor 20 further includes an end divider 23 provided at one end of the outer wall portion 21 in the transverse direction (first direction D1) such that the end divider 23 closes a space located further inward than the outer wall portion 21 and further outward than a plurality of the flow passages 22p. This makes it possible to cause the refrigerant to diverge into only the plurality of flow passages 22p.

Further, a heat exchanger 100 according to Embodiment 1 includes a plurality of heat transfer tubes 1, arrayed in the transverse direction (first direction D1), that extend in an up-down direction (second direction D2) and two headers (namely a first header 2a and a second header 2b) provided at both respective ends of the plurality of heat transfer tubes 1 and that each distribute and merge refrigerant. At least one of the two headers (e.g. the first header 2a) includes the distributor 20, and some of the plurality of heat transfer tubes 1 (in the example shown in FIG. 1, eighteen heat transfer tubes 1 on the right) are connected to the plurality of connecting ports 210 of the distributor 20. This makes it possible to achieve a heat exchanger 100 with high heat exchange efficiency, as the above distributor 20 is included in a header of the heat exchanger 100. Further, including a distributor 20 that makes it possible to both avoid an increase in pressure loss and reduce the size of the distributor 20 makes it possible to reduce the size of the header, thus making it possible to reduce the size of the heat exchanger 100.

Further, a heat pump apparatus 10 according to Embodiment 1 includes a refrigerant circuit 10a including the heat exchanger 100 and a compressor 11 configured to compress the refrigerant. This makes it possible to improve the energy-saving effectiveness of the heat pump apparatus 10 and reduce the size of the heat pump apparatus 10.

Embodiment 2

FIG. 5 is a schematic view showing the position of an orifice 22o in a cylindrical portion 22 of a distributor 20 according to Embodiment 2. FIG. 5 illustrates a cross-section of the cylindrical portion 22 perpendicular to the first direction D1. Further, in the cross-section of the cylindrical portion 22, FIG. 5 shows the liquid level Ra of refrigerant R that flows through the flow passage 22p and a liquid-level angle θ [degrees]. The term “liquid-level angle θ” here means an angle that, in the cross-section of the cylindrical portion 22 shown in FIG. 5, is formed by a reference line L0 drawn vertically downward from the center C1 of the flow passage 22p and a line L1 connecting the center C1 of the flow passage 22p with the position of the liquid level Ra on an inner surface of the cylindrical portion 22.

Embodiment 2 differs from Embodiment 1 in that the position of the orifice 22o is restricted, and is identical to Embodiment 1 in the other configurations. Components of Embodiment 2 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 2 is described with a focus on differences from Embodiment 1.

In the cross-section of the cylindrical portion 22 shown in FIG. 5, each of the plurality of orifices 22o is provided at a position at an angle to or immediately lateral to the center C1 of the flow passage 22p and each of the plurality of orifices 22o is provided at a position other than a position immediately below or immediately above the center C1 of the flow passage 22p. That is, no orifice 22 is provided immediately below or immediately above the center C1 of the flow passage 22p. Restricting the position of the orifice 22o in this way inhibits liquid refrigerant accumulated in a lower part of the flow passage 22p or gas refrigerant accumulated in an upper part of the flow passage 22p from flowing alone out of the orifice 22o with the force of gravity.

When, in a case in which the orifice 22o is provided vertically below, that is, immediately below, the center C1 of the flow passage 22p in the cylindrical portion 22, two-phase gas-liquid refrigerant flows into the flow passage 22p, liquid refrigerant preferentially flows out upstream of the distributor 20 in the longitudinal direction (first direction D1). This tends to cause a lack of refrigerant downstream of the distributor 20 in the longitudinal direction, resulting in non-uniform distribution.

In the present disclosure, providing the orifice 22o in a position off to the left or the right from a vertical line passing through the center C1 of the flow passage 22p in the cylindrical portion 22 causes the orifice 22o to be in the vicinity of the liquid level Ra of the refrigerant R. This makes it easy for both the liquid refrigerant and the gas refrigerant to flow out of the orifice 22o, bringing about improvement in uniformity of distribution.

FIG. 6 is a graph showing an effect on the liquid-level angle θ of refrigerant shown in FIG. 5 by the quality x of the refrigerant. The horizontal axis of the graph shown in FIG. 6 represents the quality x of refrigerant that flows into the heat exchanger 100, and the vertical axis of the graph shown in FIG. 6 represents the liquid-level angle θ of refrigerant that flows through the flow passage 22p shown in FIG. 5.

In general, the heat pump apparatus 10 (see FIG. 4) is used with the quality of refrigerant that flows into an evaporator being approximately 0.2 to 0.8 as shown in FIG. 6. In this case, the liquid-level angle θ is an angle of approximately 50 degrees to 70 degrees, which is smaller than 90 degrees. To cause both the liquid refrigerant and the gas refrigerant to flow out of the orifice 22o, it is thus only necessary to provide the orifice 22o at the same position as the liquid level Ra in the cross-section of the cylindrical portion 22 shown in FIG. 5. Specifically, the orifice 22o is provided such that an angle that, in FIG. 5, is formed by the reference line L0 and a line connecting the center C1 of the flow passage 22p with the center of the orifice 22o falls within an angular range of 50 degrees to 70 degrees. Further, considering the fact that the liquid level Ra is not necessarily constant in the flow passage 22p, the above angular range may be slightly widened such that the angular position in which to provide the orifice 22o may be adjusted within an angular range of 40 degrees to 80 degrees shown in FIG. 6.

Although, in FIG. 5, an angle is formed at a front in a depth direction (third direction D3) parallel with the depth of the heat exchanger 100, an angle may be formed at a rear in the depth direction (third direction D3) of the heat exchanger 100. That is, the angular position in which to provide the orifice 22o is defined by a positive angle here, and the orifice 22o may be provided at a front or a rear within the angular range from the reference line L0.

Further, the orifices 22o of the cylindrical portions 22 adjacent to each other are provided to face each other as shown in FIG. 2. Such a configuration causes jets of refrigerant out of the orifices 22o of the two cylindrical portions 22 to collide with each other, and even when there are imbalances in the distribution of refrigerant to the plurality of flow passages 22p, the effects of the imbalances are reduced prior to distribution to the plurality of heat transfer tubes 1.

The statement that the orifices 22o of the cylindrical portions 22 adjacent to each other face each other may here mean a configuration in which the directions (indicated by dashed arrows in FIG. 2) of blowout of refrigerant out of the orifices 22o of the cylindrical portions 22 adjacent to each other are close to each other rather than being parallel to each other. In the example shown in FIG. 2, the two cylindrical portions 22 are provided at a front and a rear in the hollow portion 21a in the outer wall portion 21 of the distributor 20. The cylindrical portion 22 at the front has an orifice 22o provided below and further backward than the center C1 of the flow passage 22p of the cylindrical portion 22 (e.g. at a 4 o'clock position), and the cylindrical portion 22 at the rear has an orifice 22o provided below and further forward than the center C1 of the flow passage 22p of the cylindrical portion 22 (e.g. at an 8 o'clock position).

Although in the cross-section shown in FIG. 2, the positions in the two cylindrical portions 22 where the orifices 22o are provided are symmetrical in the direction of array (third direction D3) of the cylindrical portions 22, they do not need to be strictly symmetrical. Even in a case in which the cylindrical portion 22 at the front has an orifice 22o provided at a 4 o'clock position and the cylindrical portion 22 at the rear has an orifice 22o provided at a 7 o'clock position, it is easier for the jets of refrigerant to collide with each other than in a case in which an orifice 22o is provided in the lowermost part of each cylindrical portion 22.

FIG. 7 is a schematic view showing a first modification of cylindrical portions 22 of the distributor 20 according to Embodiment 2. As shown in FIG. 7, the orifices 22o of the cylindrical portions 22 adjacent to each other may be disposed to face away from each other, that is, not to face each other. The statement that the orifices 22o of the cylindrical portions 22 adjacent to each other face away from each other may here mean a configuration in which the directions (indicated by dashed arrows in FIG. 7) of blowout of refrigerant out of the orifices 22o of the cylindrical portions 22 adjacent to each other are away from each other rather than being parallel to each other.

Although the description has so far been given, as an example, on a case in which there are two cylindrical portions 22, there may be three or more cylindrical portions 22. In a case in which there are three or more cylindrical portions 22 too, the positions of the orifices 22o may be determined according to the characteristics of distribution such that there are a portion in which orifices 22o face each other and a portion in which orifices 22o do not face each other or such that all orifices 22o face in an identical direction.

In the example shown in FIG. 7, the cylindrical portion 22 at the front has an orifice 22o provided below and further forward than the center C1 of the flow passage 22p of the cylindrical portion 22, and the cylindrical portion 22 at the rear has an orifice 22o provided below and further backward than the center C1 of the flow passage 22p of the cylindrical portion 22. Such a configuration softens the effects of a collision between jets of refrigerant out of the orifices 22o of the two cylindrical portions 22, making it possible to reduce a pressure loss. It should be noted that the number of flow passages 22p, that is, the number of cylindrical portions 22, is not limited to two.

As noted above, the distributor 20 according to Embodiment 2 too includes a plurality of cylindrical portions 22 provided in the hollow portion 21a as in the case of the distributor 20 of Embodiment 1. Therefore, Embodiment 2 brings about effects that are similar to those of Embodiment 1.

Further, in the distributor 20 according to Embodiment 2, each of the plurality of orifices 22o is provided at a position other than a position immediately below or immediately above a center C1 of the flow passage 22p in a cross-section of the corresponding cylindrical portion 22 perpendicular to the transverse direction (first direction D1).

This allows the orifice 22o to be closer to the liquid level Ra of the refrigerant R even in a state in which liquid refrigerant tends to accumulate in a lower part of the flow passage 22p by the effect of the force of gravity, thus making it possible to achieve better distribution of two-phase gas-liquid refrigerant by preventing a disproportion of liquid refrigerant in a longitudinal direction (first direction D1) of the distributor 20.

Further, each of the plurality of orifices 22o is provided such that an angle that, in the cross-section of the cylindrical portion 22 perpendicular to the transverse direction (first direction D1), is formed by a reference line L0 connecting the center C1 of the flow passage 22p with a point immediately below the center C1 of the flow passage 22p and a line connecting a point at which the orifice 22o is provided with the center C1 of the flow passage 22p falls within an angular range of larger than or equal to 40 degrees and smaller than or equal to 80 degrees.

This allows the orifice 22o to be provided in a position closer to the liquid level Ra of the refrigerant R in a distributor 20 that is used with an average quality x of refrigerant, thus making it possible to achieve more uniform distribution by making it easy for both liquid refrigerant and gas refrigerant to flow into the orifice 22o.

Embodiment 3

FIG. 8 is a cross-sectional view showing an example of a distributor 20 according to Embodiment 3. Embodiment 3 differs from Embodiment 1 in that a plurality of cylindrical portions 22 are provided in the outer wall portion 21, and is identical to Embodiment 1 in the other configurations, Components of Embodiment 3 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 3 is described with a focus on differences from Embodiment 1.

Each of the plurality of cylindrical portions 22 is provided in the outer wall portion 21 such that at least part of the flow passage 22p is located in the hollow portion 21a in a cross-section of the distributor 20 shown in FIG. 8 perpendicular to the transverse direction (first direction D1). In the example shown in FIG. 8, the two cylindrical portions 22 are coupled to each other by a portion 21b of the outer wall portion 21 located between the two cylindrical portions 22, and a lower portion of each cylindrical portion 22 protrudes from the outer wall portion 21 into the hollow portion 21a. The orifices 22o are provided in portions of the cylindrical portions 22 located in the hollow portion 21a and cause the flow passages 22p inside the cylindrical portions 22 and the hollow portion 21a outside the cylindrical portion 22 to communicate with each other.

As shown in FIG. 8, a distributor 20 in which flow passages 22p each having a substantially circular cross-section are provided in the outer wall portion 21 of the distributor 20 may be integrally molded by extrusion or other processes. It should be noted that the distributor 20 may be composed of a plurality of components. For example, a cylindrical portion 22 having a flow passage 22p that is substantially circular in cross-section may be obtained by combining upper and lower plate-like parts each having a substantially arc-shaped projection and depression.

It should be noted that the shapes of the headers are not limited to the shapes shown in FIG. 1. For example, although, in FIG. 1, each of the first and second headers 2a and 2b is configured to linearly extend in the first direction D1, it may be formed in the shape of letter U in planar view that has two linear portions extending in the first direction D1 and a bent portion connecting the two linear portions with each other. The distributor 20 of the present disclosure includes a plurality of flow passages 22p, and the amount of refrigerant that flows through each flow passage 22p is thus smaller than that in some distributor. Therefore, even in a case in which the distributor 20 is provided in a bent portion of a header having the bent portion, the effect of centrifugal force is reduced, so that the refrigerant is well distributed.

FIG. 9 is a schematic view showing a second modification of the distributor 20 according to Embodiment 3. In the second modification, the outer wall portion 21 of the distributor 20 has such a U-shaped bent portion 20b. FIG. 9 shows a cross-section of the distributor 20 perpendicular to the third direction D3 that passes through a vertex of the bent portion 20b.

Each of the plurality of orifices 22o is provided further inward in the bent portion 20b than a position immediately below the center C1 of the flow passage 22p in the cylindrical portion 22. In the example shown in FIG. 9, two cylindrical portions 22 are provided in the upper part of the outer wall portion 21, and each of the inner and outer cylindrical portions 22 has a plurality of orifices 22o provided below and further inward than the center C1 of the flow passage 22p. Accurately, of the two linear portions extending in the transverse direction in the distributor 20, the linear portion at the rear has an orifice 22o provided below and further forward than the center C1 of the flow passage 22p in each cylindrical portion 22, and the linear portion at the front has an orifice 22o provided below and further backward than the center C1 of the flow passage 22p in each cylindrical portion 22.

As noted above, the distributor 20 according to Embodiment 3 too includes a plurality of cylindrical portions 22 as in the case of the distributor 20 of Embodiment 1. Therefore, Embodiment 3 brings about effects that are similar to those of Embodiment 1.

Further, in the distributor 20 of Embodiment 3, each of the plurality of cylindrical portions 22 is provided in the outer wall portion 21 such that at least part of the flow passage 22p is located in the hollow portion 21a in a cross-section of the outer wall portion 21 perpendicular to the transverse direction (first direction D1).

This gives a configuration in which the plurality of cylindrical portions 22 are not independent from each other but coupled to each other by the outer wall portion 21. Therefore, for example, even in a case in which a process of bending a header including the distributor 20, it is easier to uniformly apply force to each of the cylindrical portions 22 than in a case in which the plurality of cylindrical portions 22 exist independently of each other. A mutual positional relationship between constituent elements of the distributor 20 is thus ensured. This results in making it possible to avoid such a problem in that after processing of a header including the distributor 20, an orifice 22o provided in each cylindrical portion 22 becomes crushed or the cylindrical portions 22 interfere with each other, making processing easy while ensuring the function.

Further, the outer wall portion 21 has a bent portion 20b, and each of the plurality of orifices 22o is provided further inward in the bent portion 20b than a position immediately below the center C1 of the flow passage 22p. This causes the orifice 22o to be provided at a position in the cylindrical portion 22 opposite to the direction of centrifugal force (in a cross-section of the cylindrical portions 22 shown in FIG. 9, the first direction D1), thus making it possible to provide good distribution even in a case in which the liquid level Ra of the refrigerant R is inclined by the centrifugal force.

Embodiment 4

FIG. 10 is a cross-sectional view showing an example of a distributor 20 according to Embodiment 4. Embodiment 4 differs from Embodiment 1 in that a plurality of cylindrical portions 22 are provided in an intermediate divider 24 disposed in the hollow portion 21a, and is identical to Embodiment 1 in the other configurations. Components of Embodiment 4 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 4 is described with a focus on differences from Embodiment 1.

The distributor 20 of Embodiment 4 is particularly effective in a case in which the distributor 20 is provided in a lower one of the first and second headers 2a and 2b shown in FIG. 1, that is, in the second header 2b. The following description describes a configuration of the distributor 20 with reference to FIG. 10 in a case in which the distributor 20 is provided in the second header 2b shown in FIG. 1.

The outer wall portion 21 of the distributor 20 has, in an upper part of the outer wall portion 21, a plurality of connecting ports 21o into which ends 1e of the plurality of heat transfer tubes 1 are inserted. The distributor 20 includes an intermediate divider 24 extending in the transverse direction (first direction D1). The intermediate divider 24 is disposed in the hollow portion 21a and divides the hollow portion 21a into upper and lower spaces. As shown in FIG. 10, the intermediate divider 24 has its front and back ends connected to an inner surface of the outer wall portion 21. In a cross-section of the distributor 20 shown in FIG. 10, the hollow portion 21a is divided into two spaces, namely a lower space 21a2 and an upper space 21a1, and the cross-sectional area of the upper space 21a1, in which the ends 1e of the plurality of heat transfer tubes 1 are disposed, is larger than the cross-sectional area of the lower space 21a2.

The plurality of cylindrical portions 22 are provided in the intermediate divider 24. Embodiment 3 is configured such that the plurality of cylindrical portions 22 are provided in the outer wall portion 21 so that the outer wall portion 21 makes it hard for the orifices 22o or other elements to become crushed. Even in a case as in Embodiment 4 in which the plurality of cylindrical portions 22 are provided in the intermediate divider 24 connected to the outer wall portion 21, effects that are similar to those of Embodiment 3 are brought about.

The intermediate divider 24 has a slit 24a that causes the lower space 21a2 and the upper space 21a1 to communicate with each other. A plurality of the slits 24a are provided in the longitudinal direction (first direction D1) of the distributor 20. Although, in the example shown in FIG. 10, only one slit 24a is provided in the depth direction (third direction D3), a plurality of the slits 24a may be provided in the depth direction. The plurality of orifices 22o in each of the plurality of cylindrical portions 22 are formed to cause one of the lower and upper spaces 21a2 and 21a1 that is located further away from the plurality of connecting ports 210 to communicate with the flow passages 22p. In a distributor 20 above which heat transfer tubes 1 are disposed as shown in FIG. 10, the plurality of orifices 22o in each of the plurality of cylindrical portions 22 are provided in a lower cylindrical part of the cylindrical portion 22 that protrudes into the lower space 21a2.

Flows of refrigerant into the plurality of flow passages 22p in the distributor 20 are ejected into the lower space 21a2 of the hollow portion 21a via the plurality of orifices 22o. The refrigerant ejected from the plurality of flow passages 22p into the lower space 21a2 flows via the slit 24a of the intermediate divider 24 into the upper space 21a1, in which the ends 1e of the plurality of heat transfer tubes 1 are disposed, and flows into the plurality of heat transfer tubes 1.

As noted above, the distributor 20 according to Embodiment 4 too includes a plurality of cylindrical portions 22 as in the case of the distributor 20 of Embodiment 1. Therefore, Embodiment 4 brings about effects that are similar to those of Embodiment 1.

Further, the distributor 20 of Embodiment 4 includes an intermediate divider 24 dividing the hollow portion 21a into upper and lower spaces and extending in the transverse direction (first direction D1). Moreover, the plurality of cylindrical portions 22 are provided in the intermediate divider 24 disposed in the hollow portion 21a. The intermediate divider 24 has a slit 24a that causes the two spaces into which the hollow portion 21a is divided, namely a lower space 21a2 and an upper space 21a1, to communicate with each other. The plurality of orifices 22o in each of the plurality of cylindrical portions 22 are formed to cause one of the lower and upper spaces 21a2 and 21a1 that is located further away from the plurality of connecting ports 21o to communicate with the flow passages 22p.

This causes the plurality of cylindrical portions 22 to be coupled to each other through the intermediate divider 24, thus making processing possible while maintaining functioning of the distributor 20 even in a case in which the header is processed. Further, a space (in the example shown in FIG. 10, the lower space 21a2) separated from the plurality of heat transfer tubes 1 by the intermediate divider 24 is thus provided, and even in a case in which the distributor 20 is provided at the lower portion of the heat transfer tubes 1, the direction of refrigerant is smoothly changed via the separated space. Moreover, the refrigerant is jetted upward via the slit 24a of the intermediate divider 24, so that the refrigerant easily flows into the heat transfer tubes 1.

Embodiment 5

FIG. 11 is a cross-sectional view showing an example of a distributor 20 according to Embodiment 5. FIG. 12 is a cross-sectional view showing a B-B cross-section of the distributor 20 shown in FIG. 11. In FIG. 12, the arrow outlines indicate directions in which refrigerant flows. Further, FIG. 12 shows a pitch P1 between heat transfer tubes 1 inserted in the distributor 20. FIG. 13 is a cross-sectional view showing a C-C cross-section of the distributor 20 shown in FIG. 11.

Embodiment 5 differs from Embodiment 1 in that a plurality of cylindrical portions 22 are different in position of an orifice 22o in the first direction D1 from each other, and is identical to Embodiment 1 in the other configurations. Components of Embodiment 5 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 5 is described with a focus on differences from Embodiment 1.

In FIG. 12, the leader lines of orifices 22o provided in the cylindrical portion 22 at the front are indicated by solid lines, and the leader lines of orifices 22o provided in the cylindrical portion 22 at the rear are indicated by dashed lines. The orifices 22o are all placed at the same pitch P2 from each other in both of the plurality of cylindrical portions 22. In a case in which a distributor 20 includes two cylindrical portions 22 as shown in FIG. 11, for example, the pitch P2 between orifices 22o in a cylindrical portion 22 as shown in FIG. 12 may be made twice as large as the pitch P1 between heat transfer tubes 1. Note, however, that the orifices 22o in the cylindrical portion 22 at the front are provided in positions different from positions where the orifices 22o are provided at the rear such that the former positons and the latter positions alternate with each other. As shown in FIGS. 12 and 13, into odd-numbered ones of the plurality of heat transfer tubes 1 connected to the distributor 20 as counted from the left, refrigerant is thus ejected out of the orifices 22o provided in the cylindrical portion 22 at the front. Further, into even-numbered ones of the plurality of heat transfer tubes 1 as counted from the left, refrigerant is ejected out of the orifices 22o provided in the cylindrical portion 22 at the rear.

For example, in a case in which the pitch P1 between heat transfer tubes 1 is such a narrow pitch as less than 10 [mm], an attempt to provide a larger number of orifices 22o in each cylindrical portion 22 than the number of heat transfer tubes 1 ends up narrowing the pitch between orifices 22o. This makes it difficult to form the orifices 22o in the cylindrical portion 22 in manufacturing and makes the cylindrical portion 22 weak against pressure.

To address this problem, as noted above, the distributor 20 according to Embodiment 5 is configured such that the orifices 22o of the cylindrical portions 22 adjacent to each other are provided in different positions that alternate with each other in the transverse direction (first direction D1).

This increases the pitch P2 between orifices 22o provided in each cylindrical portion 22, makes it easy to provide one orifice 22o per heat transfer tube 1, and makes it possible to secure good distribution. Furthermore, increasing the pitch P2 between orifices 22o makes it possible to avoid difficulties in manufacturing and improves resistance to pressure.

Embodiment 6

FIG. 14 is a cross-sectional view showing an example of a distributor 20 according to Embodiment 6. Embodiment 6 differs from Embodiment 1 in the number of orifices 22o provided in each cylindrical portion 22 in a cross-section of the distributor 20 perpendicular to the transverse direction (first direction D1), and is identical to Embodiment 1 in the other configurations. Components of Embodiment 6 that are identical to those of Embodiment 1 are given identical reference signs, and Embodiment 6 is described with a focus on differences from Embodiment 1.

As shown in FIG. 14, a plurality of the orifices 22o are provided in the same plane (i.e. a cross-section shown in FIG. 14). In the example shown in FIG. 14, two cylindrical portions 22 are provided at a front and a rear in the hollow portion 21a in the outer wall portion 21 of the distributor 20. The cylindrical portion 22 at the front has an orifice 22o provided below and further forward than the center C1 of its flow passage 22p and an orifice 22o provided below and further backward than the center C1 of the flow passage 22p, and the cylindrical portion 22 at the rear has also an orifice 22o provided below and further forward than the center C1 of its flow passage 22p and an orifice 22o provided below and further backward than the center C1 of the flow passage 22p.

Providing a plurality of orifices 22o in a cross-section of a cylindrical portion 22 makes it possible to provide better distribution even in a case in which there are imbalances in the distribution of liquid refrigerant in the cylindrical portion 22, as the presence of the plurality of orifices 22o uniforms distribution of refrigerant flowing into the heat transfer tubes 1. Further, the presence of a plurality of orifices 22o in a cross-section of a cylindrical portion 22 does not only secure uniformity but also gives a configuration in which an intentionally unequally higher proportion of liquid or gas is distributed. The plurality of orifices 22o do not need to be provided in the same plane across the whole distributor 20. With a configuration in which a plurality of orifices 22o in the same plane are only provided in part of the distributor 20, heat exchange in the whole of a heat exchanger including the distributor 20 is efficiently carried out, for example, by deliberately distributing less refrigerant to a portion in which there is a decrease in heat exchange amount due to pipes or other components provided around when the distributor 20 is mounted in a product or other articles.

Further, the shapes of the orifices 22o in Embodiment 6 may be slit-like shapes, and the number of orifices 22o may be smaller than or equal to the number of heat transfer tubes 1, that is, the number of connecting ports 210 provided in the outer wall portion 21. Furthermore, the orifices 22o do not need to be identical in shape or size across the whole cylindrical portion 22, and the area of each of the orifices 22o only in part of the cylindrical portion 22 may be large. In other words, the size of each of the orifices 22o provided in a part of the cylindrical portion 22 may be different from the size of each of the orifices 22o provided in another part of the cylindrical portion 22. For example, by varying the shape and size of the orifices 22o in the cylindrical portion 22 or providing as many or fewer orifices 22o as or than heat transfer tubes 1, refrigerant is caused to be distributed with an intentionally unequally higher proportion of liquid or gas in a given portion.

As noted above, in the distributor 20 according to Embodiment 6, one of the cylindrical portions 22 has a plurality of the orifices 22o provided in an identical plane perpendicular to the flow passage 22p. This makes it possible to provide better distribution even in a case in which there are imbalances in the distribution of liquid refrigerant in the cylindrical portion 22, as the presence of the plurality of orifices 22o uniforms distribution of refrigerant flowing into the heat transfer tubes 1. Further, appropriately adjusting the number of orifices 22o that are provided in the same cross-section of the cylindrical portion 22 makes it possible to not only secure uniformity but also distribute an intentionally unequally higher proportion of liquid or gas, bringing about increase in degree of freedom of distribution.

It should be noted that it is possible to combine one of the embodiments with another or to modify or omit any of the embodiments as appropriate. For example, in each of the embodiments too, the shapes of the orifices 22o may be slit-like shapes, and the number of orifices 22o may be smaller than or equal to the number of heat transfer tubes 1, that is, the number of connecting ports 210 provided in the outer wall portion 21. Furthermore, the orifices 22o do not need to be identical in shape or size across the whole cylindrical portion 22, and the area of each of the orifices 22o only in part of the cylindrical portion 22 may be large.

REFERENCE SIGNS LIST

1: heat transfer tube, 1e: end, 2a: first header, 2b: second header, 3a: pipe, 3b: pipe, 4: divider, 10: heat pump apparatus, 10a: refrigerant circuit, 11: compressor, 12: flow switching device, 13: heat exchanger, 14: pressure reducer, 20: distributor, 20b: bent portion, 21: outer wall portion, 21a: hollow portion, 21a1: upper space, 21a2: lower space, 21b: portion, 21o: connecting port, 22: cylindrical portion, 22o: orifice, 22p: flow passage, 23: end divider, 23a: opening, 24: intermediate divider, 24a: slit, 100: heat exchanger, C1: center, D1: first direction, D2: second direction, D3: third direction, L0: reference line, L1: line, P1: pitch, P2: pitch, R: refrigerant, Ra: liquid level, x: degree, E: liquid-level angle

DISTRIBUTOR, HEAT EXCHANGER, AND HEAT PUMP APPARATUS

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