JP3247087B2 - Piping structure including heat exchanger and air conditioner using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piping structure including a heat exchanger and an air conditioner using the same.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner operated under a wide range of outdoor temperature and indoor temperature conditions, by changing the operating frequency of a compressor in accordance with the heat load in each condition. What has enhanced energy-saving effects is the mainstream. For this reason, in response to a change in the refrigerant circulation amount due to a change in the operating frequency of the compressor (for example, maximum refrigerant circulation amount / minimum refrigerant circulation amount) 10), each device constituting the air conditioner also appropriately operates in a wide operating range. It needs to function. In such an air conditioner, to optimize the performance and ensure the reliability of the compressor,
The degree of opening of the electric expansion valve is controlled so that the state of the refrigerant sucked by the compressor is 0.95 and the degree of superheat is 5 deg.

[0003] FIG. 8 (A) shows a multi-path inlet-side distributor of the cross section of the heat exchanger of the conventional air conditioner, X _B -X _B of FIG. 8 (B) FIG. 8 (A) 2 shows a cross section of the flow divider inlet pipe 101 as viewed from the line. As shown in FIG. 8 (A), one end of a flow divider inlet pipe 101 is connected to the inlet side of the flow divider 102, and one end of the flow divider pipes 104 and 105 are connected to the outlet side.
In the above-described air conditioner, when the heat exchange ratio on the air side of each path is substantially constant irrespective of a change in air flow, the flow splitter 10
The flow state of the two-phase flow before splitting according to FIG. 2 (FIG. 8 (A), FIG.
(Refer to the liquid phase portion 105 shown in (B)), the refrigerant circulating flow rate changes, and the liquid refrigerant flow rate flowing in each path changes, so that refrigerant drift occurs, and the refrigerant-side cooling capacity of each path changes, and the degree of superheat increases. There is a disadvantage that the performance is degraded because a path having a large degree of heat and a path having a small degree of superheat occur. In addition, the air conditioner has a drawback in that non-dehumidified air that has passed through a heat exchanger having a large degree of superheat touches an outlet or the like to cause dew condensation, thereby causing a problem such as water leakage. Also, when the refrigerant flow is high speed, a shear component due to the velocity acts, and liquids and gases having different densities are almost uniformly dispersed in the cross section of the pipe. In, the lower side in the direction of gravity becomes liquid-rich.

Therefore, two flow dividers having a throttle provided on the inlet side have been proposed. As shown in FIG. 9, the first flow divider connects one end of the flow divider inlet pipe 111 to the flow divider 11.
2 is connected to the inlet side of
An aperture 113 having 13a is arranged. And
Dividing pipe 11 is inserted into holes 114b and 114c provided in bottom 114 fixed and fitted on the outlet side in flow dividing device 112.
One end of each of 5,116 is inserted and fixed. In the flow divider 112, even if the flow of the refrigerant is low, the restrictor 11
3 to increase the flow rate of the refrigerant, and
The refrigerant passing through a is caused to collide with the collision wall 114a of 114,
Divide the refrigerant uniformly.

Further, as shown in FIG. 10, a second flow divider provided with a throttle at the other inlet side connects one end of a flow divider inlet pipe 121 to an inlet side of a flow divider 122 and an outlet side. Are connected to one ends of flow dividing tubes 123 and 124, respectively.
A small-diameter throttle portion 122a is provided on the inlet side of the flow divider 122, and the outlet side of the flow divider 122 is bifurcated into an inverted U-shape, and a collision wall 122b is provided at the branch point, so that the refrigerant flow rate can be reduced. Even if the speed is low, the throttle unit 122a
As a result, the mist-like refrigerant that has passed through the throttle portion 122a collides against the collision wall 122b, thereby uniformly dividing the refrigerant.

However, in the air conditioners using the first and second flow dividers 112 and 122 shown in FIGS. 9 and 10, since the refrigerant passing sound is generated due to the pressure fluctuation in the throttle portions 113 and 122, the vibration control is performed. It is necessary to take countermeasures with putty, etc., which increases costs and also requires installation space for anti-vibration putty, etc., so the heat exchanger that can be mounted on products with limited space becomes smaller and the performance decreases. is there.

Also, in an air conditioner that divides the refrigerant after making the refrigerant into a homogeneous liquid state using a capillary, the refrigerant passing noise is generated by the decompression by the capillary, so that it is necessary to take countermeasures such as an anti-vibration putty and the cost is high. In addition, there is a problem that an installation space for a capillary, a vibration-proof putty, and the like is required. Further, in the air conditioner, since the capillary is used, the amount of pressure reduction that can be controlled by the electric expansion valve is very small, the range in which performance can be optimally controlled becomes narrow, and the operating frequency can be controlled. Even if an inverter is used, its performance cannot be exhibited, and the energy saving effect is reduced.

Further, in an air conditioner using a branch pipe without using a flow divider in consideration of cost, the operating frequency of the compressor is controlled so that the drift does not become less than the circulating amount of the refrigerant, which is a problem. The range of performance that can be operated according to the required heat load is narrowed, and the energy saving effect is reduced.

[0009] Furthermore, in an air conditioner in which the inlet pipe of the flow divider is made vertical to eliminate the influence of gravity, in order to eliminate the influence of bending, a straight line allowance of about 100 times the inner diameter is required. In order to eliminate the influence of the variation in the angle with respect to the vertical, a pipe fixing member for fixing the flow splitter inlet pipe is required, which increases the cost and also requires the installation space for the flow splitter inlet pipe and the pipe fixing member. is there.

Accordingly, an object of the present invention is to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of changes in the refrigerant flow rate and to prevent the refrigerant passage noise with a simple configuration, thereby reducing cost and space. An object of the present invention is to provide a piping structure including a heat exchanger that can be achieved and an air conditioner using the same.

[0011]

In order to achieve the above object, a pipe structure including a heat exchanger according to the first aspect of the present invention comprises a multi-pass heat exchanger having a plurality of refrigerant paths, and an inlet of the heat exchanger. A flow divider connected to the outlet side, and an inlet pipe connected to the inlet side of the flow divider and provided with a swirling flow generating means inside, and the swirling flow generating means is provided inside the inlet pipe. A multi-helical groove provided, wherein the twist angle of the multi-spiral groove with respect to the axis of the inlet pipe is 10 degrees or more and 30 degrees or less, and the depth of the multi-helical groove with respect to the minimum inner diameter of the inlet pipe. It is characterized in that the ratio of the heights is 0.02 or more.

According to the piping structure including the heat exchanger according to the first aspect of the present invention, by providing a swirling flow generating means inside the inlet piping, a swirling flow is generated in the refrigerant flowing through the inlet piping. The influence of gravity is eliminated also in the flow rate, and the liquid gas distribution in the cross section of the inlet pipe is made uniform, and the refrigerant drift in the heat exchanger is reduced in a wide range of the refrigerant flow rate. Further, since a flow divider having a throttle portion is not used, no refrigerant passing sound is generated. Therefore, with a simple configuration, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of changes in the refrigerant flow rate, prevent the passage of the refrigerant, and reduce the cost and space. Further, the refrigerant flowing in the inlet pipe is guided by the surrounding multi-helical groove, so that a swirling flow can be generated effectively. Further, according to an experiment conducted by the present applicant, the twist angle of the multiple spiral groove with respect to the axis of the inlet pipe is 10 degrees or more and 30 degrees or less, and the depth of the multiple spiral groove with respect to the minimum inner diameter of the inlet pipe is If the ratio is 0.02 or more, the drift width (temperature difference between the refrigerant temperature on the outlet side of one path of the heat exchanger and the refrigerant temperature on the outlet side of the other path) becomes 3 deg or less, and there is no practical problem. It has been found that the refrigerant drift is suppressed to a certain extent. In addition,
The torsion angle of the multiple spiral groove with respect to the axis of the inlet pipe is 1
When the temperature is less than 0 degrees or exceeds 30 degrees, the refrigerant drift increases, and the drift width exceeds 3 deg. Further, when the ratio of the depth of the multi-helix groove to the minimum inner diameter of the inlet pipe is less than 0.02, the refrigerant drift increases and the drift width exceeds 3 deg, so that the heat exchange efficiency decreases. . Therefore, the torsion angle of the multiple spiral groove with respect to the axis of the inlet pipe is set to 10 degrees or more and 30 degrees or less, and the ratio of the depth of the multiple spiral groove to the minimum inner diameter of the inlet pipe is set to 0.02 or more. Thereby, the refrigerant drift in the heat exchanger can be surely reduced.

Further, the piping structure including the heat exchanger according to the second aspect is a multi-pass type heat exchanger having a plurality of refrigerant paths, and is connected to the inlet side of the heat exchanger and has a swirling flow generating means inside. The spiral flow generating means is a multi-spiral groove provided inside the inlet pipe, and the twist angle of the multi-spiral groove with respect to the axis of the inlet pipe is 10 °. Degrees or more and 30 degrees or less, and the ratio of the depth of the multiple spiral groove to the minimum inner diameter of the inlet pipe is 0.02 or more.

According to the piping structure including the heat exchanger of the second aspect, for example, when a branch pipe is used on the inlet side of the heat exchanger without using a flow splitter, the inlet pipe connected to the branch pipe is used. By providing the swirling flow generating means inside the inside, the swirling flow occurs in the refrigerant flowing in the inlet pipe, so that the influence of gravity is eliminated even at a low refrigerant flow rate, and the liquid gas distribution in the inlet pipe cross section is made uniform, The refrigerant drift in the heat exchanger is reduced in a wide range of the refrigerant flow rate. Further, since a flow divider having a throttle portion is not used, no refrigerant passing sound is generated.
Therefore, with a simple configuration, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of changes in the refrigerant flow rate, prevent the passage of the refrigerant, and reduce the cost and space. Further, the refrigerant flowing in the inlet pipe is guided by the surrounding multi-helical groove, so that a swirling flow can be generated effectively. Further, according to an experiment conducted by the present applicant, the twist angle of the multiple spiral groove with respect to the axis of the inlet pipe is 10 degrees or more and 30 degrees or less, and the depth of the multiple spiral groove with respect to the minimum inner diameter of the inlet pipe is The ratio is 0.0
If it is 2 or more, the drift width (the difference between the temperature of the refrigerant at the outlet of one path of the heat exchanger and the temperature of the refrigerant at the outlet of the other path) is 3 deg or less, and the drift of the refrigerant becomes practically negligible. Was found to be suppressed. Note that when the twist angle of the multi-helical groove with respect to the axis of the inlet pipe is less than 10 degrees or exceeds 30 degrees, the refrigerant drift increases and the drift width exceeds 3 deg, so that the heat exchange efficiency decreases. . Further, when the ratio of the depth of the multi-helix groove to the minimum inner diameter of the inlet pipe is less than 0.02, the refrigerant drift increases and the drift width exceeds 3 deg, so that the heat exchange efficiency decreases. . Therefore, the torsion angle of the multiple spiral groove with respect to the axis of the inlet pipe is set to 10 degrees or more and 30 degrees or less, and the ratio of the depth of the multiple spiral groove to the minimum inner diameter of the inlet pipe is set to 0.02 or more. Thereby, the refrigerant drift in the heat exchanger can be surely reduced.

[0015] The air conditioner of the third aspect is characterized by the first aspect.
Alternatively, a piping structure including the second heat exchanger is used.

According to the air conditioner of the third aspect, with a simple configuration, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of refrigerant flow changes, and to prevent the refrigerant passage noise, thereby reducing the cost. An air conditioner that can save space can be realized.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piping structure including a heat exchanger according to the present invention and an air conditioner using the same will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a schematic configuration diagram of an air conditioner using a piping structure including a heat exchanger according to an embodiment of the present invention, wherein 1 is a compressor and 2 is connected to the discharge side of the compressor 1. The four-way valve 3 is an outdoor heat exchanger having one end connected to the four-way valve 2, 4 is a decompressor having one end connected to the other end of the outdoor heat exchanger 3, 5 is One end is connected to the other end of the decompressor 4, and the other end is an indoor heat exchanger connected to the suction side of the compressor 1 via the four-way valve 2. In the air conditioner, when the four-way valve 2 is switched to the position indicated by the solid line and the compressor 1 is driven during the cooling operation, the refrigerant discharged from the compressor 1 causes the outdoor heat exchanger 3 serving as a condenser to operate. Condensed,
After the pressure is further reduced by the decompressor 4, the refrigerant is evaporated by the indoor heat exchanger 5 as an evaporator and returns to the compressor 1.

FIG. 2 is a diagram showing a piping structure including the heat exchanger 5 on the indoor side of the air conditioner. In FIG. 2, the heat exchanger 5 includes a rear heat exchange section 5A and a front heat exchange section 5A.
B is disposed in a casing (not shown) in a state of being bent in a U-shape. The rear-side heat exchange section 5A and the front-side heat exchange section 5B are arranged with a plurality of fin plates 14 bent in a dogleg shape at predetermined intervals in a direction perpendicular to the plane of FIG. The plurality of heat transfer tubes penetrate the plurality of fin plates 14, and the first refrigerant path 11 is provided to the rear heat exchange unit 5 </ b> A.
Is formed, and the second and third refrigerant paths 1 are formed in the front-side heat exchange section 5B.
2, 13 are formed respectively. The first refrigerant path 11
Penetrates the shorter curved portion 14A of the fin plate 14 from the port 11A toward the far side in the vertical direction of the paper surface in FIG. 2, and turns toward the near side in the vertical direction of the paper surface to turn the fin plate 14
And extends from the upper end to the lower end of the rear heat exchange portion 5A of the fin plate 14 in the same manner. In addition, the second coolant flow path 12 penetrates from a position slightly above the middle of the longer curved portion 14B of the fin plate 14 along the outer peripheral side so as to sew in the vertical direction of the paper surface. And extends along the inner peripheral side. Similarly, the third coolant channel 13 is provided in the fin plate 1.
4 along substantially the middle of the longer curved portion 14B of the longer side and along the outer peripheral side in a direction perpendicular to the paper surface.
At the lower end of the curved portion 14B, and extends along the inner peripheral side.

The other end of the flow divider inlet pipe 21 having one end connected to the other end of the pressure reducer 4 (shown in FIG. 1) is connected to the flow divider 2.
2 is connected to the entrance side. The other end of the flow dividing tube 23A, one end of which is connected to the outlet side of the flow divider 22, is connected to one port 11A of the first refrigerant path 11. In addition, the other end of the flow dividing tube 23 </ b> B having one end connected to the other outlet side of the flow divider 22 is connected to one port 12 </ b> A of the second refrigerant path 12. Further, the other end of the flow dividing pipe 23 </ b> C whose one end is connected to the other outlet of the flow divider 22 is connected to one port 13 </ b> A of the third refrigerant path 13. The other end of the branch pipe 31A having one end connected to the other port 11B of the first refrigerant path 11 is connected to the port 32A of the merger 32. Further, the other end of the branch pipe 31B, one end of which is connected to the other port 12B of the second refrigerant path 12, is connected to the port 32B of the merger 32. Further, the other end of the branch pipe 31C having one end connected to the other port 13B of the third refrigerant path 13 is connected to the port 3 of the merger 32.
Connected to 2C.

The heat exchanger 5, the flow distributor 22 and the flow distributor inlet piping 21 constitute a piping structure including a heat exchanger.

FIG. 3 is a sectional view of a main part excluding the heat exchanger 5 having a piping structure including the above heat exchanger. FIG. 3 shows only the branch pipes 23A and 23B, and the branch pipe 23C shown in FIG.
Is not shown. As shown in FIG.
Is a cylindrical small-diameter portion 22a in which one end of the flow divider inlet pipe 21 is internally fitted and fixed, a conical portion 22b connected to the small-diameter portion 22a and having a conical diameter, and a conical portion 22b.
And a large-diameter portion 22c in the shape of a cylinder connected to. A bottom 24 is fitted and fixed inside the end of the large-diameter portion 22c of the flow divider 22, and one end of each of the distribution pipes 23A and 23B is fitted and fixed in holes 24a and 24b provided in the bottom 24, respectively. are doing. Further, a multi-spiral groove 40 is provided inside the distributor inlet pipe 21. FIG. 4A is a cross-sectional view of the flow divider inlet pipe 21, and a multi-spiral groove 40 as a circulating flow generating means is provided inside the flow divider inlet pipe 21.

As shown in FIG. 4B, the present applicant sets the minimum inner diameter D of the flow divider inlet pipe 21 and the depth h of the multi-helix groove 40 as shown in FIG. An experiment was performed under the following conditions, where the torsion angle of the flow divider inlet pipe 21 with respect to the axis was θ.

First, as shown in FIG. 5, a flow divider inlet pipe 51 into which the refrigerant flows is connected to the inlet side of the flow divider 52, and the outlet side of the flow divider 52 is connected to the second path heat exchanger 50. 1
The refrigerant path 53 and one end of the second refrigerant path 54 are connected to each other to form a piping structure including a heat exchanger. Then, the other ends of the first refrigerant path 53 and the second refrigerant path 54 are connected to the inlet side of the merger 55. This diverter inlet pipe 5
1. A circuit constituted by the flow divider 52, the heat exchanger 50 and the merger 55 is connected to a refrigerant circuit (not shown) as an evaporator. The heat exchange area, air volume, and the like of the first refrigerant path 53 and the second refrigerant path 54 of the two-pass heat exchanger 50 are made the same. Further, the mass flow rate of the refrigerant flowing into the branch pipe inlet pipe 51 is set to 50 kg / m ² · s, and the superheat degree at the outlet side of the merger 55 is set to 5 deg. Using a plurality of inlet pipes, each having a different depth h / minimum inner diameter D, for the splitter inlet pipe 51, the drift width (first
The temperature difference between the refrigerant temperature at the outlet 53A of the refrigerant path 53 and the refrigerant temperature at the outlet 54A of the second refrigerant path 54 was measured.

FIGS. 6 and 7 show the measurement results of the above experiment. FIG. 6 shows the depth / minimum inner diameter (= h / D) of the multi-spiral groove of the inlet pipe 51 of the flow divider 0.01,0.0. .02,0.0
Curves A, B, and C show changes in the drift width with respect to the torsion angle θ of the multi-helical groove for each of the four spiral grooves. As shown in FIG. 6, in the curve A of the drift width when the depth / minimum inner diameter is 0.01,
The minimum value of the drift width is as large as about 4 deg, which is far out of the range (the drift width of 0 to 3 deg) S1 where there is no practical problem. On the other hand, in the curve B of the drift width when the depth / minimum inner diameter is 0.02, the torsion angle θ is in the range of 10 degrees to 30 degrees and is within the region S1 where there is no practical problem. Further, in the curve C of the drift width when the depth / minimum inner diameter is 0.04, the torsion angle θ is in a range wider than 10 degrees to 30 degrees and is within a region S1 where there is no practical problem.

FIG. 7 shows that the torsion angle θ of the multi-helical groove of the inlet pipe 51 is changed every 5, 10, 20, 30 degrees.
Curves D, E, and F show the change in the drift width with respect to the depth / minimum inner diameter (= h / D) of the multi-helical groove. As shown in FIG. 7, in the curve D of the drift width when the twist angle θ is 5 degrees, the minimum value of the drift width is as large as about 4 deg, which is larger than the practically problem-free region (drift width of 0 to 3 deg) S1. Is off. On the other hand, in the curve E of the drift width when the torsion angle θ is 10 degrees or 30 degrees, the depth / minimum inner diameter is in the range of 0.02 or more and is within the region S2 where there is no practical problem. Furthermore, in the curve F of the drift width when the twist angle θ is 20 degrees, the depth /
When the minimum inner diameter is in the range of 0.02 or more, it is within the region S2 where there is no practical problem. In FIG. 7, the case where the depth / minimum inner diameter of the multi-helical groove is 0.07 is the manufacturing limit of the multi-helical groove processed inside the inlet pipe.

As described above, by using the flow divider inlet pipe 21 provided with the multi-helical groove 40 inside, the refrigerant flowing in the flow divider inlet pipe 21 generates a swirling flow, so that even at a low refrigerant flow rate, The influence of gravity is eliminated, the distribution of liquid gas in the cross section of the inlet pipe is made uniform, the refrigerant drift in the heat exchanger 5 in a wide range of the refrigerant flow rate is eliminated, and the refrigerant passage noise due to the throttle portion of the flow divider is not generated.
Therefore, with a simple configuration without adding new members, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of refrigerant flow rate changes, and also to prevent refrigerant passage noise, thereby achieving cost reduction and space saving. An air conditioner can be realized.

Further, by setting the twist angle θ of the multi-helical groove 40 with respect to the axis of the branch inlet pipe 21 to 10 degrees or more and 30 degrees or less, the refrigerant drift in the heat exchanger 5 can be surely reduced. .

Further, by setting the ratio of the depth of the multi-helical groove 40 to the minimum inner diameter of the flow divider inlet pipe 21 to be 0.02 or more, it is possible to reliably reduce the refrigerant drift in the heat exchanger 5. .

In the above embodiment, an air conditioner using a piping structure including a heat exchanger has been described. However, the piping structure including the heat exchanger of the present invention is not limited to an air conditioner, and is applied to a refrigerator or the like. Of course, it may be possible.

In the above embodiment, the piping structure including the indoor heat exchanger 5 has been described. However, the present invention may be applied to a piping structure including an outdoor heat exchanger. In this case, in the heating operation in which the outdoor heat exchanger becomes an evaporator, the outlet side of the flow divider is connected to the inlet side of the outdoor heat exchanger, and the multi-spiral groove is provided inside the inlet side of the flow divider. Connect the inlet pipe provided at

Further, in the above embodiment, the multi-pass type heat exchanger 5 having a plurality of refrigerant paths and the heat exchanger 5
A flow distributor 22 having an outlet connected to the inlet side of the flow distributor, and a flow distributor inlet pipe 21 connected to the inlet side of the flow distributor 22 and having a multi-spiral groove 40 as a swirling flow generating means provided inside. Although the piping structure including the heat exchanger has been described, a multi-pass type heat exchanger having a plurality of refrigerant paths, and an inlet piping connected to the inlet side of the heat exchanger and provided with a swirling flow generating means inside. The present invention may be applied to a piping structure including a heat exchanger having the following.

[0033]

As is apparent from the above description, the piping structure including the heat exchanger according to the first aspect of the present invention includes a multi-pass type heat exchanger having a plurality of refrigerant paths and a heat exchanger at the inlet side of the heat exchanger. A flow divider connected to an outlet side, and an inlet pipe connected to the inlet side of the flow divider and provided with a swirling flow generating means inside, the swirling flow generating means is provided inside the inlet pipe. Wherein the torsion angle of the multi-helix groove with respect to the axis of the inlet pipe is 10 degrees or more and 30 degrees or less, and the depth of the multi-helix groove with respect to the minimum inner diameter of the inlet pipe is The ratio is 0.02 or more.

Therefore, according to the piping structure including the heat exchanger of the first aspect of the present invention, since the swirling flow is generated in the refrigerant flowing in the inlet pipe by the swirling flow generating means, the influence of gravity is exerted even at a low refrigerant flow rate. In this case, the liquid gas distribution in the cross section of the inlet pipe is made uniform, the refrigerant drift in the heat exchanger is reduced in a wide range of the refrigerant flow rate, and no refrigerant passing sound is generated because the flow divider having the throttle portion is not used. Therefore, with a simple configuration, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of changes in the refrigerant flow rate, prevent the passage of the refrigerant, and reduce the cost and space. In addition, since the swirling flow generating means is a multi-spiral groove provided inside the inlet pipe, the refrigerant flowing in the inlet pipe is guided by the surrounding multi-spiral groove, thereby effectively generating a swirling flow. Can be caused. The twist angle of the multi-helical groove with respect to the axis of the inlet pipe is 10
Degree or more and 30 degrees or less, and the ratio of the depth of the multi-helical groove to the minimum inner diameter of the inlet pipe is 0.02 or more. The temperature difference between the refrigerant temperature and the temperature of the refrigerant on the outlet side of the other path) is 3 deg or less, and the refrigerant drift in the heat exchanger can be reliably reduced.

The piping structure including the heat exchanger according to the second aspect of the present invention is a multi-pass heat exchanger having a plurality of refrigerant paths, connected to the inlet side of the heat exchanger, and having a swirling flow inward. An inlet pipe provided with a generating means, wherein the swirling flow generating means is a multi-spiral groove provided inside the inlet pipe, and a torsion angle of the multi-spiral groove with respect to an axis of the inlet pipe. Is not less than 10 degrees and not more than 30 degrees, and the ratio of the depth of the multiple spiral groove to the minimum inner diameter of the inlet pipe is 0.02 or more.

Therefore, according to the piping structure including the heat exchanger according to the second aspect of the present invention, since the swirling flow is generated in the refrigerant flowing through the inlet piping by the swirling flow generating means, the influence of gravity is exerted even at a low refrigerant flow rate. In this case, the liquid gas distribution in the cross section of the inlet pipe is made uniform, the refrigerant drift in the heat exchanger is reduced in a wide range of the refrigerant flow rate, and no refrigerant passing sound is generated because the flow divider having the throttle portion is not used. Therefore, with a simple configuration, it is possible to prevent the refrigerant from drifting in the heat exchanger with respect to a wide range of changes in the refrigerant flow rate, prevent the passage of the refrigerant, and reduce the cost and space. In addition, since the swirling flow generating means is a multi-spiral groove provided inside the inlet pipe, the refrigerant flowing in the inlet pipe is guided by the surrounding multi-spiral groove, thereby effectively generating a swirling flow. Can be caused. The twist angle of the multi-helical groove with respect to the axis of the inlet pipe is 10
Degree or more and 30 degrees or less, and the ratio of the depth of the multi-helical groove to the minimum inner diameter of the inlet pipe is 0.02 or more. The temperature difference between the refrigerant temperature and the temperature of the refrigerant on the outlet side of the other path) is 3 deg or less, and the refrigerant drift in the heat exchanger can be reliably reduced.

Further, the air conditioner according to the third aspect of the present invention uses the piping structure including the heat exchanger according to the first or second aspect. In addition to preventing the refrigerant from drifting, the refrigerant passage noise can be prevented, and an air conditioner that can achieve cost reduction and space saving can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner using a piping structure including a heat exchanger according to an embodiment of the present invention.

FIG. 2 is a diagram showing a piping structure including a heat exchanger of the air conditioner.

FIG. 3 is a sectional view of a main part of a piping structure including the heat exchanger.

4 (A) is a sectional view of an inlet pipe of a pipe structure including the heat exchanger, and FIG. 4 (B) is an enlarged view of a main part of FIG. 4 (A); (C) is a diagram showing a state where the inlet pipe is opened.

FIG. 5 is a view showing experimental conditions of a piping structure including the heat exchanger.

FIG. 6 is a diagram showing a change in a drift width with respect to a torsion angle in a piping structure including the heat exchanger.

FIG. 7 is a view showing a change in a drift width with respect to a groove depth / minimum inner diameter in a piping structure including the heat exchanger.

[8] FIG. 8 (A) is a sectional view of a conventional flow divider, FIG. 8 (B) is a sectional view taken X _B -X _B line in FIG. 8 (A).

FIG. 9 is a cross-sectional view of a conventional flow divider having a restrictor.

FIG. 10 is a cross-sectional view of another conventional flow splitter having a throttle portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Outdoor heat exchanger, 4 ... Pressure reducer, 5 ... Indoor heat exchanger, 11 ... 1st refrigerant path, 12 ... 2nd refrigerant path, 13 ... Third refrigerant path, 14: Fin plate, 21: Divider inlet piping, 22: Divider, 23A, 23B, 23C: Divider pipe, 31A, 31B, 31C: Branch pipe, 32: Merger, 40: Multi-spiral groove.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeharu Hira 1000-2 Oya, Okamoto-cho, Kusatsu-shi, Shiga Daikin Industries, Ltd. Shiga Works (72) Inventor Junichiro Tanaka 1000-Oya, Okamotocho, Kusatsu-shi, Shiga (2) Reference: JP-A-2-97863 (JP, A) JP-A-2-71065 (JP, A) JP-A-58-40467 (JP, A) 1-307595 (JP, A) Full-open sho 57-5683 (JP, U) Full-open sho 61-136272 (JP, U) Full-open sho 59-132058 (JP, U) Full-open sho 64-35369 (JP, U U) Actually open sho 59-178570 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 41/00

Claims (3)

(57) [Claims] 1. A multi-pass type heat exchanger (5) having a plurality of refrigerant paths, and a flow divider having an outlet side connected to an inlet side of the heat exchanger (5).
(22), and an inlet pipe (21) connected to the inlet side of the flow divider (22) and provided with a swirling flow generating means inside, wherein the swirling flow generating means includes the inlet pipe (21). Spiral groove (40) provided on the inside of
The torsion angle of the multi-helical groove (40) with respect to the axis of (21) is 10 degrees or more and 30 degrees or less, and the inlet pipe (2
A piping structure including a heat exchanger, wherein the ratio of the depth of the multi-helical groove (40) to the minimum inner diameter of 1) is 0.02 or more. 2. A multi-pass type heat exchanger having a plurality of refrigerant paths, and an inlet pipe connected to an inlet side of the heat exchanger and having a swirling flow generating means provided on an inner side thereof. The generating means is a multiple spiral groove (40) provided inside the inlet pipe (21),
The torsion angle of the multi-helical groove (40) with respect to the axis of (21) is 10 degrees or more and 30 degrees or less, and the inlet pipe (2
A piping structure including a heat exchanger, wherein the ratio of the depth of the multi-helical groove (40) to the minimum inner diameter of 1) is 0.02 or more. 3. An air conditioner using a piping structure including the heat exchanger according to claim 1.