BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a refrigerant distributor that distributes a refrigerant
to each heat exchanger tube in a heat exchanger including a plurality of heat exchanger
tubes.
Description of the Related Art
[0002] In a large air conditioner such as a commercial use air conditioner, a larger heat
exchanger than that in a home or vehicle air conditioner is used. When a small diameter
tube is used as a heat exchanger tube, such a large heat exchanger generally has a
multi-circuit configuration including multiple sets of heat exchange circuits using
a plurality of heat exchanger tubes to reduce refrigerant pressure loss in the heat
exchanger and increase heat exchange performance.
[0003] When the heat exchanger is an evaporator, a refrigerant expanded at an inlet of the
evaporator is in a gas-liquid two-phase state with a gas phase and a liquid phase
mixed. In a tube, the refrigerant in the gas-liquid two-phase state forms an annular
flow in which a liquid phase is distributed to an outer peripheral side in the tube
and a gas phase is distributed to a center of the tube, which causes nonuniform distribution
of a gas-liquid ratio in a sectional direction of the tube. When such a refrigerant
is distributed to a plurality of heat exchanger tubes in the heat exchanger, a gas-liquid
ratio between the liquid phase and the gas phase differs depending on the heat exchanger
tubes. Then, efficiency of a heat exchange with the refrigerant differs between a
heat exchanger tube with many liquid phases and a heat exchanger tube with many gas
phases, which reduces performance of the entire heat exchanger.
[0004] Thus, various distributors have been proposed improved so as to provide uniform distribution
of a gas-liquid ratio of a refrigerant in a two-phase state between a plurality of
heat exchanger tubes.
[0005] For example, as shown in FIG. 9, between a refrigerant tube 1 on an upstream side
and a heat exchanger 2, a refrigerant distributor 4 is provided that distributes a
refrigerant in a two-phase state conveyed by a refrigerant tube 1 to each branch tube
3 of the heat exchanger 2. As shown in FIG. 10, the refrigerant distributor 4 includes
an increased diameter portion 5 having an inner diameter gradually increasing from
the refrigerant tube 1, a cylindrical portion 6 continuous with a large diameter side
of the increased diameter portion 5, and a closing plate 7 that closes the cylindrical
portion 6. In an outer peripheral portion of the closing plate 7, connection holes
8 for connection of the branch tubes 3 are provided at circumferentially spaced intervals
in a concentric circular position with respect to a center of the closing plate 7.
Thus, in the refrigerant distributor 4, the refrigerant is fed from the concentric
circular position to each branch tube 3 to provide uniform distribution of a gas-liquid
ratio of the refrigerant in the two-phase state between the plurality of branch tubes
3.
[0006] However, from a situation of a flowing path to the heat exchanger (an effect of a
centrifugal force due to a curvature of a bent portion of the refrigerant tube 1,
etc.) or an effect of an operation state change (dryness, flow state change), or the
like, the gas-liquid ratio of the refrigerant in the two-phase state may differ even
in the concentric circular position in the refrigerant distributor 4. Thus, it is
difficult to cause the refrigerant to flow into the heat exchanger tubes in a constantly
uniform two-phase state. In particular, it is difficult to stably distribute the refrigerant
in the two-phase state in a wide flow rate range including a state with a low flow
rate of the refrigerant and a state with a high flow rate.
[0007] Such a problem is noticeable for a heat exchanger including smaller diameter heat
exchanger tubes and a larger number of heat exchanger tubes.
[0008] Thus, a configuration has been also proposed in which a refrigerant is subjected
to gas-liquid separation before being distributed to each heat exchanger tube (for
example, see Japanese Patent No.
3416963 and Japanese
Patent Laid-Open No.
2008-267689).
[0009] For example, in Japanese Patent No.
3416963, a centrifugal force is used to perform gas-liquid separation of a refrigerant, and
only a liquid refrigerant is supplied to each heat exchanger tube in a heat exchanger.
[0010] Japanese Patent Laid-Open No.
2008-267689 discloses a configuration in which a groove is formed in an inner peripheral surface
of a tube to generate a swirl flow of a refrigerant, and a centrifugal force thereof
causes gas-liquid separation of the refrigerant.
[0011] However, the configuration in which the refrigerant is subjected to the gas-liquid
separation by centrifugal separation and separated into a liquid refrigerant and a
gas refrigerant, and then only the liquid refrigerant is distributed to a plurality
of heat exchanger tubes increases a size of the entire apparatus configuration and
increases costs.
[0012] Also, in the configuration in which the groove is formed in the inner peripheral
surface of the tube for generating the centrifugal force, particularly for a large
heat exchanger with a high refrigerant flow rate, the tube formed with the groove
in the inner peripheral surface has a large diameter. This increases a size of an
apparatus configuration and thus increases costs, and also the swirl flow of the refrigerant
cannot be efficiently generated even if the groove is formed in the large diameter
tube.
[0013] The present invention is achieved based on such technical problems, and has an object
to provide a refrigerant distributor that does not increase a size of an apparatus
configuration and cost even when constituting a large air conditioner, and can stably
distribute a refrigerant in a two-phase state in a wide flow rate range.
SUMMARY OF THE INVENTION
[0014] To achieve the above-described object, the present invention provides a refrigerant
distributor that is provided in a heat exchanger and distributes and feeds a refrigerant
into each of a plurality of heat exchanger tubes that constitute the heat exchanger,
including: a hollow body into which a refrigerant with a liquid phase and a gas phase
mixed is fed from a refrigerant tube to a lower end thereof; a cap provided on an
upper end of the body, and to which the plurality of heat exchanger tubes placed at
circumferentially spaced intervals along an outer peripheral portion of the body are
connected; and a return member that returns at least a part of the refrigerant fed
from the refrigerant tube into the body downward in the body.
[0015] The return member returns the liquid phase that is at least a part of the refrigerant
fed from the refrigerant tube into the body downward in the body, and thus the liquid
phase can be distributed to a lower portion in the body, and the gas phase can be
distributed to an upper portion.
[0016] Such a return member can be constituted by an underside of the cap.
[0017] Also, the return member may be constituted by an annular ring provided to face an
upper portion of a tube wall of the refrigerant tube. In this case, the ring preferably
has a guide portion that is located closer to the inner peripheral side than the tube
wall of the refrigerant tube and extends downward.
[0018] Such a return member is effective when the refrigerant tube has distribution in which
the liquid phase of the refrigerant flows along an inner wall surface of the refrigerant
tube, and the gas phase of the refrigerant flows through a center of the refrigerant
tube. The return member returns a liquid phase portion flowing through an outer peripheral
portion of the refrigerant tube is returned to the lower portion, and a gas phase
portion flowing through the center of the refrigerant tube is passed to the upper
portion and collected in the upper portion in the body, thereby allowing the refrigerant
to be vertically separated into two liquid and gas phases in the body.
[0019] A first suction port is preferably further formed that opens at the lower portion
in the body and sucks and feeds the refrigerant into the heat exchanger tube. Thus,
the liquid phase of the refrigerant can be sucked from the lower portion in the body
and fed into the heat exchanger tube.
[0020] A second suction port may be further formed that opens at the upper portion in the
body and sucks and feeds the refrigerant into the heat exchanger tube. Thus, the gas
phase of the refrigerant can be sucked from the upper portion in the body and fed
into the heat exchanger tube. Then, in the heat exchanger tube, the refrigerant is
in a two-phase state with the liquid phase sucked from the first suction port and
the gas phase sucked from the second suction port, but the liquid phase and the gas
phase are vertically separated in the body, which can provide a uniform mixing ratio
between the liquid phase and the gas phase of the refrigerant between the plurality
of heat exchanger tubes.
[0021] Further, a bypass tube may be provided that sucks the refrigerant from the upper
portion in the body and bypasses the refrigerant to an exit side of the heat exchanger.
Both the second suction port and the bypass tube may be provided, or only one thereof
may be provided. When the second suction port is not provided and only the bypass
tube is provided, uniform gas-liquid two phases with many liquid phases are fed into
the heat exchanger tube, and the same advantage can be obtained.
[0022] An increased diameter portion with a gradually increasing area of a channel through
which the refrigerant flows may be provided between an upper end of the refrigerant
tube and the body. In the increased diameter portion, the flow of the refrigerant
becomes a jet, and thus the refrigerant becomes droplets.
[0023] The present invention may provide a refrigerant distributor that is provided in a
heat exchanger and distributes and feeds a refrigerant to each of a plurality of heat
exchanger tubes that constitute the heat exchanger, including: a hollow body into
which a refrigerant with a liquid phase and a gas phase mixed is fed from a refrigerant
tube to a lower end thereof; a cap provided on an upper end of the body, and to which
a plurality of heat exchanger tubes placed at circumferentially spaced intervals along
an outer peripheral portion of the body are connected; and an increased diameter portion
that is provided between an upper end of the refrigerant tube and the body and has
a gradually increasing area of a channel through which the refrigerant flows.
[0024] According to the present invention, a refrigerant with a uniform mixing ratio between
the liquid phase and the gas phase can be fed into each heat exchanger tube. Thus,
the refrigerant in the two-phase state can be stably distributed to the plurality
of heat exchanger tubes, and a heat exchange with the refrigerant can be stably performed
in a wide flow rate range. Heat exchange performance can be stabilized to reduce a
size of the heat exchanger and thus reduce cost of the entire air conditioner. Further,
the refrigerant distributor has a very simple configuration, and thus the above-described
advantage can be provided at low cost without increasing the size of the air conditioner
or cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
FIG. 1 is a sectional view showing a refrigerant distributor according to a first
embodiment;
FIG. 2 is a sectional view showing a refrigerant distributor according to a second
embodiment;
FIG. 3A is a plan view of a gas-liquid separation ring view and FIG. 3B is a sectional
view thereof;
FIG. 4 is a sectional view showing a variant of the refrigerant distributor according
to the second embodiment;
FIG. 5 is a sectional view showing a refrigerant distributor according to a third
embodiment;
FIG. 6 is a sectional view showing a variant of the refrigerant distributor according
to the third embodiment;
FIG. 7 is a sectional view showing another variant of the refrigerant distributor
according to the third embodiment;
FIG. 8 is a sectional view of a configuration shown in the second embodiment being
combined with the refrigerant distributor according to the third embodiment;
FIG. 9 is a perspective view of a conventional refrigerant distributor; and
FIG. 10A is a plan view of a conventional refrigerant distributor and FIG. 10B is
a front sectional view thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Now, embodiments of the present invention will be described in detail with reference
to the accompanying drawings.
[0027] FIG. 1 illustrates a configuration of a refrigerant distributor 10A according to
this embodiment. The refrigerant distributor 10A is provided in a heat exchanger (evaporator)
in an air conditioner.
[0028] As shown in FIG. 1, the refrigerant distributor 10A includes a body 13 having a lower
end connected to a refrigerant tube 11 on an upstream side, and an upper end to which
a plurality of capillary tubes 12 that constitute the heat exchanger are connected.
[0029] The body 13 is hollow, and includes at a lower end thereof a cylindrical refrigerant
tube connecting portion 14 to which the refrigerant tube 11 is connected. The body
13 includes a bowl-shaped increased diameter portion 15 continuous with an upper end
of the refrigerant tube connecting portion 14 and having an inner diameter gradually
increasing upward, and a cylindrical portion 16 continuous with an upper end of the
increased diameter portion 15 and extending upward.
[0030] The refrigerant tube 11 connected to the refrigerant tube connecting portion 14 has
an upper end 11a protruding upward from the refrigerant tube connecting portion 14
and located inside the cylindrical portion 16.
[0031] In an opening at an upper end of the cylindrical portion 16, a disk-shaped cap 17
that closes the opening is fitted. In an outer peripheral portion of the cap 17, a
predetermined number of capillary tubes 12 are inserted at circumferentially spaced
intervals in a concentric circular position from a center of the cap 17 and pass through
the cap 17 to a lower side thereof.
[0032] A cylindrical sleeve 20 is housed in the cylindrical portion 16. The sleeve 20 has
a double structure including an outer cylinder 21, and an inner cylinder 22 having
a smaller diameter than the outer cylinder 21, and an annular gap S is formed between
the outer cylinder 21 and the inner cylinder 22. The outer cylinder 21 and the inner
cylinder 22 are integrally connected at a plurality of circumferential positions by
unshown connecting portions. A lower end 12a of capillary tube 12 passing through
the cap 17 opens in an upper portion of the gap S.
[0033] A lower end 22a of the inner cylinder 22 is located above the lower end 21a of the
outer cylinder 21. Thus, at a lower end of the sleeve 20, an opening 23 opening toward
an inner peripheral side of the sleeve 20 is circumferentially formed.
[0034] A plurality of through holes 24 that pass through opposite surfaces of the inner
cylinder 22 are formed in circumferential positions in an upper portion of the sleeve
20. The through hole 24 is preferably formed in a position corresponding to each capillary
tube 12.
[0035] In such a refrigerant distributor 10A, when a refrigerant in a gas-liquid two-phase
state flows from the refrigerant tube 11 in a lower position, the refrigerant flows
from the upper end 11a of the refrigerant tube 11 located inside the cylindrical portion
16 into the body 13. In the refrigerant having flown into the cylindrical portion
16, a liquid phase of the refrigerant having mainly flown through an outer peripheral
side in the refrigerant tube 11 collides with an underside of the cap 17 and returns
downward to form a liquid film flow. Then, the liquid film flow reaches a bottom of
the body 13 (an inner peripheral surface of a portion from the lower end of the cylindrical
portion 16 to the increased diameter portion 15 below the upper end 11a of the refrigerant
tube 11), while a gas phase of the refrigerant mainly flowing through a center in
the refrigerant tube 11 remains in the upper portion in the body 13. Thus, in the
body 13, the refrigerant is easily vertically separated into a gas phase and a liquid
phase according to the difference in specific gravity. Thus, in the body 13, many
liquid phases of the refrigerant accumulate in the position below the upper end 11a
of the refrigerant tube 11, and many gas phases accumulate in the position above the
upper end 11a of the refrigerant tube 11.
[0036] Then, from the opening 23 opening on the inner peripheral side of the lower end of
the sleeve 20, the liquid phase of the refrigerant is mainly sucked up and sucked
through the gap S into each capillary tube 12. At this time, the refrigerant sucked
from the opening 23 may partly contain the gas phase.
[0037] From the through hole 24 opening at the upper portion of the sleeve 20, the gas phase
of the refrigerant is mainly sucked into each capillary tube 12. Thus, in the capillary
tube 12, the liquid phase of the refrigerant having flown through the opening 23 and
the gas phase having flown through the through hole 24 are mixed, and a gas-liquid
two-phase refrigerant flows.
[0038] As described above, from the refrigerant tube 11 in which the liquid phase of the
refrigerant is distributed to the outer peripheral side, and the gas phase is distributed
to the center, the refrigerant in the two-phase state is caused to collide with the
cap 17 provided in the upper portion of the body 13 of the refrigerant distributor
10A, and thus the refrigerant can be vertically separated into the gas phase and the
liquid phase in the body 13. Then, the liquid phase of the refrigerant is sucked up
from the opening 23 opening at the lower end of the sleeve 20, and the gas phase of
the refrigerant is sucked from the through hole 24 opening at the upper portion of
the sleeve 20, and thus the refrigerant with a uniform mixing ratio between the liquid
phase and the gas phase can be fed into each capillary tube 12.
[0039] Thus, in the refrigerant distributor 10A, the refrigerant in the two-phase state
can be stably distributed to the plurality of capillary tube 12, and a stable heat
exchange with the refrigerant can be performed in a wide flow rate range. Heat exchange
performance can be stabilized to reduce a size of the heat exchanger and thus reduce
cost of the entire air conditioner. Further, the refrigerant distributor 10A has a
very simple configuration, and thus the above-described advantage can be provided
with minimum cost increase, without increasing the size of the air conditioner or
cost.
[Second embodiment]
[0040] Next, a second embodiment of the present invention will be described. In the description
below, configurations different from those in the first embodiment will be mainly
described, and the same configurations as those in the first embodiment will be denoted
by the same reference numerals and the descriptions thereof will be omitted.
[0041] As shown in FIG. 2, a refrigerant distributor 10B in this embodiment is different
from the refrigerant distributor 10A in the first embodiment in that a gas-liquid
separation ring (return member, ring) 30 is provided.
[0042] The gas-liquid separation ring 30 is provided at a predetermined space below a cap
17. The gas-liquid separation ring 30 has an outer peripheral portion abutting against
a step 27 from below. The step 27 is formed below a through hole 24 in a sleeve 20.
A cylindrical securing member 28 is inserted from below on an inner peripheral side
of an inner cylinder 22 of the sleeve 20. The gas-liquid separation ring 30 is held
between the securing member 28 and the step 27 and fixed.
[0043] As shown in FIGS. 2 and 3A, 3B, the gas-liquid separation ring 30 has a disk shape
with a predetermined thickness, and includes an outer peripheral ring 31 held between
the securing member 28 and the step 27 as described above, an inner peripheral ring
32 concentrically placed inside the outer peripheral ring 31, and a plurality of spokes
33 that connect the outer peripheral ring 31 and the inner peripheral ring 32.
[0044] The inner peripheral ring 32 is provided vertically above a tube wall 11b of a refrigerant
tube 11 protruding in a body 13. More specifically, the inner peripheral ring 32 has
a smaller inner diameter than an inner diameter of the refrigerant tube 11, and includes
an annular plate portion 32a having a larger outer diameter than an outer diameter
of the refrigerant tube 11, an inner peripheral side cylindrical portion (guide portion)
32b extending downward from an inner peripheral side of the plate portion 32a, and
an outer peripheral side cylindrical portion 32c extending downward from an outer
peripheral side of the plate portion 32a. Thus, the inner peripheral ring 32 has an
inverted U-shaped sectional shape opening downward. Then, above the refrigerant tube
11, in the inner peripheral ring 32, the inner peripheral side cylindrical portion
32b is located closer to the inner peripheral side than the tube wall 11b of the refrigerant
tube 11, and the outer peripheral side cylindrical portion 32c is located closer to
the outer peripheral side than the tube wall 11b of the refrigerant tube 11.
[0045] A central opening 34 formed at a center of the inner peripheral ring 32 is located
vertically above a center of the refrigerant tube 11.
[0046] In the refrigerant distributor 10B with such a configuration, when a refrigerant
in a gas-liquid two-phase state flows from the refrigerant tube 11 in a lower position,
the refrigerant flows from the upper end 11a of the refrigerant tube 11 located inside
the cylindrical portion 16 into the body 13. In the refrigerant having flown into
the cylindrical portion 16, a liquid phase of the refrigerant having flown along an
inner peripheral surface of the refrigerant tube 11 collides with the inner peripheral
ring 32 of the gas-liquid separation ring 30 located above the tube wall 11b to form
a liquid film flow and returns downward. Then, the liquid film flow reaches a bottom
of the body 13, while a gas phase of the refrigerant mainly flowing through the center
in the refrigerant tube 11 flows through the central opening 34 on the inner peripheral
side of the inner peripheral ring 32 to an upper position of the gas-liquid separation
ring 30.
[0047] In the inner peripheral ring 32, the inner peripheral side cylindrical portion 32b
has the inverted-U shape located closer to the inner peripheral side than the tube
wall 11b of the refrigerant tube 11. Thus, the liquid phase of the refrigerant having
flown along the inner peripheral surface of the tube wall 11b of the refrigerant tube
11, that is, the liquid film flow is diverted as if to be torn from a flow closer
to the inner peripheral side than the inner peripheral side cylindrical portion 32b,
and changed in flow direction to a downward direction. Thus, the liquid phase can
be more efficiently pressed into a lower portion of the body 13.
[0048] Also, the gas phase of the refrigerant having passed through the central opening
34 of the inner peripheral ring 32 collides with an underside of the cap 17 and returns,
and again returns from an upper surface of the plate portion 32a of the inner peripheral
ring 32. Thus, the gas phase can be more efficiently accumulated in the upper portion
of the body 13.
[0049] As such, the gas-liquid separation ring 30 can be provided to more efficiently separate
the liquid phase of the refrigerant from the gas phase thereof.
[0050] Then, the liquid phase of the refrigerant is mainly sucked up from the opening 23
opening on the inner peripheral side at the lower end of the sleeve 20, and the gas
phase of the refrigerant is sucked from the through hole 24 opening in the upper portion
of the refrigerant sleeve 20 into each capillary tube 12. Thus, the refrigerant with
a uniform mixing ratio between the liquid phase and the gas phase can be fed into
each capillary tube 12.
[0051] Thus, as in the first embodiment, the refrigerant in the two-phase state can be stably
distributed, and a stable heat exchange with the refrigerant can be performed in a
wide flow rate range to reduce a size of the heat exchanger and thus reduce cost.
Further, the refrigerant distributor 10B has a very simple configuration as in the
first embodiment, and the above-described advantage can be provided at low cost without
increasing the size of the air conditioner or cost.
[0052] In the first and second embodiments, variants described below may be adopted. Specifically,
as shown in FIG. 4, a refrigerant distributor 10C may include a bypass tube 35 that
sucks out the gas phase of the refrigerant accumulated in the upper portion in the
body 13 to the cap 17, and bypasses the gas phase to an exit side of the heat exchanger.
With such a configuration, the gas phase of the refrigerant is bypassed to the exit
side, and thus the refrigerant can be fed from the capillary tube 12 into the heat
exchanger as the liquid phase (single phase).
[0053] This can further increase heat exchange efficiency in the heat exchanger. Thus, even
with a light load in the heat exchanger and a low flow rate of the refrigerant flowing
through the heat capillary tube 12, the heat exchange can be reliably performed. Such
a configuration is particularly effective for reducing a size of the heat exchanger,
and adopting such a configuration can reduce a size of the air conditioner and cost.
[Third embodiment]
[0054] Next, a third embodiment of the present invention will be described. In the description
below, configurations different from those in the first embodiment will be mainly
described, and the same configurations as those in the first embodiment will be denoted
by the same reference numerals and the descriptions thereof will be omitted.
[0055] As shown in FIG. 5, a refrigerant distributor 10D in this embodiment includes a body
41 having a lower end to which a refrigerant tube 11 on an upstream side is connected
via a diffusion tube 40, and an upper end to which a plurality of capillary tube 12
that constitute a heat exchanger are connected.
[0056] The body 41 is hollow, and includes a cylindrical refrigerant tube connecting portion
14, a bowl-shaped increased diameter portion 15 continuous with an upper end of the
refrigerant tube connecting portion 14 and having an inner diameter gradually increasing
upward, and a cylindrical portion 16 continuous with an upper end of the increased
diameter portion 15 and extending upward.
[0057] In an opening at an upper end of the cylindrical portion 16, a disk-shaped cap 17
that closes the opening is fitted. In an outer peripheral portion of the cap 17, a
predetermined number of capillary tube 12 are inserted at circumferentially spaced
intervals in a concentric circular position from a center of the cap 17 and pass through
the cap 17 to a lower side thereof.
[0058] The diffusion tube 40 includes a diffusion tube member 45 including a tube holding
portion 42 into which an upper end 11a of the refrigerant tube 11 is inserted, a bowl-shaped
increased diameter portion 43 continuous with an upper end of the tube holding portion
42 and having an inner diameter gradually increasing upward, and a cylindrical straight
tube portion 44 continuous with an upper end of the increased diameter portion 43
and extending upward. In an example in FIG. 5, between the refrigerant tube 11 and
the body 41, diffusion tube members 45 are connected in two steps. The number of steps
of the diffusion tube member 45 is not limited to two, but only one step or three
or more steps may be allowed. A diffusion tube member 45 of the second step or thereafter
is connected by inserting a straight tube portion 44 of a diffusion tube member 45
on the lower step side into a tube holding portion 42.
[0059] Such diffusion tube members 45 are connected so that the refrigerant tube 11 or the
straight tube portion 44 of the diffusion tube member 45 protrudes upward from the
tube holding portion 42 of the diffusion tube member 45 on the upper step side or
the refrigerant tube connecting portion 14.
[0060] Such a diffusion tube 40 is provided, and thus an inner diameter of a channel thereof
is suddenly increased at an upper end of the refrigerant tube 11 or an upper end 45a
of the diffusion tube member 45, a flow of the refrigerant that is an annular flow
in which a liquid phase is distributed to an outer peripheral portion and a gas phase
is distributed to a center becomes a jet, and the liquid phase refrigerant becomes
droplets. Thus, a thickness of a liquid film flow L along an inner peripheral surface
of the diffusion tube 40 becomes smaller than a thickness of a liquid film flow L
along the refrigerant tube 11.
[0061] Conventionally, the gas phase is sometimes separated from the liquid phase in the
body due to an operation state (dryness due to a load change, flow state change) to
prevent uniform distribution in a concentric circular shape. For this case, the liquid
phase of the refrigerant in droplets is sucked by the capillary tube 12 connected
to the upper portion of the body 41, and thus the liquid film of the annular flow
can be made uniform to splash a uniform droplet flow. Thus, the refrigerant with a
uniform mixing ratio between the liquid phase and the gas phase can be fed into the
plurality of capillary tube 12 connected to the body 41.
[0062] Thus, in the refrigerant distributor 10D, the refrigerant in the two-phase state
can be stably distributed to the plurality of capillary tubes 12, and a heat exchange
with the refrigerant can be stably performed in a wide flow rate range. Heat exchange
performance can be stabilized to reduce a size of the heat exchanger and thus reduce
cost of the entire air conditioner. Further, the refrigerant distributor 10D has a
very simple configuration, and thus the above-described advantage can be provided
at low cost without increasing the size of the air conditioner or cost.
[0063] In the third embodiment, a variant as described below may be adopted.
[0064] First, as shown in FIG. 6, the lower end 12a of the capillary tube 12 connected to
the body 41 may have a downward increasing diameter. This can increase an opening
area of the capillary tube 12 facing the inside of the body 41, and allows droplets
of the refrigerant to be collected from a wider range, and thus the above-described
advantage is obtained in a more noticeably manner.
[0065] Also, as shown in FIG. 7, a guide portion 47 that protrudes downward and can guide
a flow of droplets to the capillary tube 12 placed in the outer peripheral portion
of the cap 17 may be formed in an underside of the cap 17. Such a guide portion 47
may have, for example, a conical shape having a sectional area gradually decreasing
downward.
[0066] With such a guide portion 47, the droplets can be guided to the capillary tube 12
on the outer peripheral side, thus can be more efficiently collected in the capillary
tube 12, and thus the above-described advantage is obtained in a more noticeably manner.
[0067] As shown in FIG. 8, a gas-liquid separation ring 30 may be provided above the diffusion
tube 40 in the body 41 as in the configuration in FIG. 2. In this case, the diffusion
tube 40 reduces a thickness of the liquid film flow, and thus as in the second embodiment,
the ring 30 can divert the liquid film of the tube wall downward to suck the liquid
phase from a lower portion of the body 41, and can more reliably supply a uniform
droplet flow.
[0068] In the above-described embodiments, the configuration of the heat exchanger itself
or the configuration of the entire air conditioning apparatus is not limited.
[0069] Further, the configurations described in the embodiments may be chosen or changed
to other configurations without departing from the gist of the present invention.
1. A refrigerant distributor that is provided in a heat exchanger and distributes and
feeds a refrigerant into each of a plurality of heat exchanger tubes that constitute
the heat exchanger, comprising:
a hollow body into which the refrigerant with a liquid phase and a gas phase mixed
is fed from a refrigerant tube to a lower end thereof;
a cap provided on an upper end of the body, and to which the plurality of heat exchanger
tubes placed at circumferentially spaced intervals along an outer peripheral portion
of the body are connected; and
a return member that returns at least a part of the refrigerant fed from the refrigerant
tube into the body downward in the body.
2. The refrigerant distributor according to claim 1, wherein the return member is constituted
by an underside of the cap.
3. The refrigerant distributor according to claim 1, wherein the return member is constituted
by an annular ring provided to face an upper portion of a tube wall of the refrigerant
tube.
4. The refrigerant distributor according to claim 3, wherein the ring has a guide portion
extending downward on an inner peripheral side of the tube wall of the refrigerant
tube.
5. The refrigerant distributor according to any one of claims 1 to 4, wherein the refrigerant
tube has distribution in which the liquid phase of the refrigerant flows along an
inner wall surface of the refrigerant tube, and the gas phase of the refrigerant flows
through a center of the refrigerant tube.
6. The refrigerant distributor according to any one of claims 1 to 5, further comprising
a first suction port that opens at the lower portion in the body and sucks and feeds
the refrigerant into the heat exchanger tube.
7. The refrigerant distributor according to claim 6, further comprising a second suction
port that opens at the upper portion in the body and sucks and feeds the refrigerant
into the heat exchanger tube.
8. The refrigerant distributor according to claim 6 or 7, further comprising a bypass
tube that sucks the refrigerant from the upper portion in the body and bypasses the
refrigerant to an exit side of the heat exchanger.
9. The refrigerant distributor according to any one of claims 1 to 8, wherein an increased
diameter portion with a gradually increasing area of a channel through which the refrigerant
flows is provided between an upper end of the refrigerant tube and the body.
10. A refrigerant distributor that is provided in a heat exchanger and distributes and
feeds a refrigerant to each of a plurality of heat exchanger tubes that constitute
the heat exchanger, comprising:
a hollow body into which the refrigerant with a liquid phase and a gas phase mixed
is fed from a refrigerant tube to a lower end thereof;
a cap provided on an upper end of the body, and to which a plurality of the heat exchanger
tubes placed at circumferentially spaced intervals along an outer peripheral portion
of the body are connected; and
an increased diameter portion that is provided between an upper end of the refrigerant
tube and the body and has a gradually increasing area of a channel through which the
refrigerant flows.